Subjects -> CHEMISTRY (Total: 928 journals)
    - ANALYTICAL CHEMISTRY (59 journals)
    - CHEMISTRY (661 journals)
    - CRYSTALLOGRAPHY (23 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (45 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (65 journals)

CHEMISTRY (661 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
Accounts of Materials Research     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 32)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 16)
ACS Catalysis     Hybrid Journal   (Followers: 57)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 26)
ACS Combinatorial Science     Hybrid Journal   (Followers: 13)
ACS Environmental Au     Open Access   (Followers: 10)
ACS Macro Letters     Hybrid Journal   (Followers: 29)
ACS Materials Letters     Open Access   (Followers: 7)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 45)
ACS Nano     Hybrid Journal   (Followers: 224)
ACS Photonics     Hybrid Journal   (Followers: 16)
ACS Symposium Series     Full-text available via subscription   (Followers: 5)
ACS Synthetic Biology     Hybrid Journal   (Followers: 39)
Acta Chemica Malaysia     Open Access   (Followers: 2)
Acta Chimica Slovaca     Open Access   (Followers: 4)
Acta Chimica Slovenica     Open Access   (Followers: 4)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 10)
Acta Scientifica Naturalis     Open Access   (Followers: 4)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 9)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 12)
Adsorption Science & Technology     Open Access   (Followers: 9)
Advanced Electronic Materials     Hybrid Journal   (Followers: 13)
Advanced Functional Materials     Hybrid Journal   (Followers: 76)
Advanced Journal of Chemistry, Section A     Open Access   (Followers: 4)
Advanced Journal of Chemistry, Section B     Open Access   (Followers: 1)
Advanced Science Focus     Free   (Followers: 8)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 131)
Advances in Chemical Science     Open Access   (Followers: 52)
Advances in Chemistry     Open Access   (Followers: 37)
Advances in Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 15)
Advances in Environmental Chemistry     Open Access   (Followers: 13)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 34)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 49)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Sample Preparation     Open Access   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 18)
Aerosol Science and Engineering     Hybrid Journal   (Followers: 2)
African Journal of Chemical Education     Open Access   (Followers: 6)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Aggregate     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 2)
Alchemy : Jurnal Penelitian Kimia     Open Access  
Alfarama Journal of Basic & Applied Sciences     Open Access   (Followers: 8)
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 45)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 21)
American Journal of Chemistry     Open Access   (Followers: 37)
American Journal of Plant Physiology     Open Access   (Followers: 9)
Analyst     Hybrid Journal   (Followers: 35)
Analytical Science Advances     Open Access   (Followers: 2)
Angewandte Chemie     Hybrid Journal   (Followers: 169)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 275)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 6)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 4)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 5)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 14)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 20)
Applied Surface Science     Hybrid Journal   (Followers: 31)
Arabian Journal of Chemistry     Open Access   (Followers: 4)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Asian Journal of Chemical Sciences     Open Access   (Followers: 1)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 8)
Autophagy     Hybrid Journal   (Followers: 8)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Hybrid Journal   (Followers: 248)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 24)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 3)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 85)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 61)
Bioorganic Chemistry     Hybrid Journal   (Followers: 7)
Biopolymers     Hybrid Journal   (Followers: 15)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 25)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 5)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 1)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 11)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Polymer Technologies and Applications     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 11)
Carbohydrate Research     Hybrid Journal   (Followers: 23)
Carbon     Hybrid Journal   (Followers: 64)
Carbon Capture Science & Technology     Open Access   (Followers: 1)
Carbon Trends     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 12)
Cell Reports Physical Science     Open Access   (Followers: 1)
Cellulose     Hybrid Journal   (Followers: 8)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
Chem     Hybrid Journal   (Followers: 7)
Chem Catalysis     Hybrid Journal   (Followers: 1)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 3)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Hybrid Journal   (Followers: 83)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 27)
Chemical Physics Impact     Full-text available via subscription   (Followers: 1)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 4)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 214)
Chemical Science     Open Access   (Followers: 43)
Chemical Science International Journal     Open Access  
Chemical Technology     Open Access   (Followers: 75)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 4)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 39)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 18)
ChemInform     Hybrid Journal   (Followers: 5)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Industry     Full-text available via subscription   (Followers: 6)
Chemistry - A European Journal     Hybrid Journal   (Followers: 145)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 20)
Chemistry Africa : A Journal of the Tunisian Chemical Society     Hybrid Journal  
Chemistry and Materials Research     Open Access   (Followers: 19)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 7)
Chemistry Education Review     Open Access   (Followers: 2)
Chemistry in Education     Open Access   (Followers: 5)
Chemistry Letters     Full-text available via subscription   (Followers: 43)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 5)
Chemistry of Materials     Hybrid Journal   (Followers: 186)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Hybrid Journal   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal  
Chemistry–Methods     Open Access   (Followers: 3)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
Chemosensors     Open Access   (Followers: 1)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPhysMater     Full-text available via subscription  
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access  
ChemSystemsChem     Hybrid Journal   (Followers: 1)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Open Access   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 9)
Chromatographia     Hybrid Journal   (Followers: 21)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 4)
Ciencia     Open Access  
Clay Minerals     Hybrid Journal   (Followers: 9)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 6)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 2)
Combustion Science and Technology     Hybrid Journal   (Followers: 26)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Communications Chemistry     Open Access   (Followers: 2)
Communications Materials     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 6)

        1 2 3 4 | Last

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Number of Followers: 1  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2227-9040
Published by MDPI Homepage  [258 journals]
  • Chemosensors, Vol. 11, Pages 313: Novel Robust Internal Calibration
           Procedure for Precise FT-IR Measurements of Nitrogen Impurities in

    • Authors: Roman Khmelnitsky, Oleg Kovalchuk, Alexey Gorevoy, Pavel Danilov, Daniil Pomazkin, Sergey Kudryashov
      First page: 313
      Abstract: FT-IR spectroscopy is the basic finger-print method for qualitative and quantitative analysis of nitrogen, boron, and hydrogen impurities in natural and synthetic diamonds. In quantitative measurements of impurity concentrations, external standard samples are required for the calibration procedure during the analysis. In this study, the double-phonon mid-IR absorption coefficient of optical phonons of the diamond host matrix, the robust internal mid-IR absorption standard, was accurately measured for tens of diverse diamond samples, thus enabling precise calibrated measurements of ultra-low detectable impurity concentrations.
      Citation: Chemosensors
      PubDate: 2023-05-23
      DOI: 10.3390/chemosensors11060313
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 314: Electrochemical Sensitivity Improvement
           by the Cooperation between Pt and Ru for Total Antioxidant Evaluation in
           Natural Extracts

    • Authors: Gustavo Carvalho Diniz, Vinicius Tribuzi Rodrigues Pinheiro Gomes, Marcelo de Assis, Santiago José Alejandro Figueroa, Igor Ferreira Torquato, Luiz Gustavo de Freitas Borges, Hector Aguilar Vitorino, Roberto Batista de Lima, Marco Aurélio Suller Garcia, Isaíde de Araujo Rodrigues
      First page: 314
      Abstract: Herein, a straightforward electrochemical method was used to evaluate the total phenolic antioxidant capacity in natural extracts prepared from pomegranate, hibiscus, and pitaya. In light of this, the well-known electrochemical index (EI), a screening protocol for natural antioxidant properties evaluation, was determined using differential pulse voltammetry. Initially considering rutin and catechin as standards, we found that the system’s sensitivity greatly increased by using platinum (Pt) and platinum/ruthenium (Pt/Ru) nanoparticles (NPs) immobilized on Vulcan XC-72 to modify screen-printed carbon electrodes (SPCEs). When such modifications were applied to natural fruit/plant extracts, their electrochemical ability proved highly superior to the bare SPCE, even considering a very small amount of materials for electrode preparation. However, with an optimized ratio, the bimetallic counterpart was more sensitive to detection. When the pomegranate extract was used, for example, EI values of 52.51 ± 6.00 and 104.79 ± 6.89 µA/V were obtained using Pt and Pt/Ru (with an optimized ratio) electrocatalysts, showing the remarkable sensitivity increase obtained in our bimetallic protocol. Thus, based on physicochemical and electrochemical characterizations, we found that the ruthenium content was essential for the achievements. In due course, XPS analysis suggested that the Pt2+/Pt0 species ratio could have improved the system’s sensitivity, which significantly changed when ruthenium was used in the material.
      Citation: Chemosensors
      PubDate: 2023-05-23
      DOI: 10.3390/chemosensors11060314
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 315: UIO-66/Ag/TiO2 Nanocomposites as Highly
           Active SERS Substrates for Quantitative Detection of Hexavalent Chromium

    • Authors: Zixiang Ben, Guangran Ma, Fugang Xu
      First page: 315
      Abstract: Sensitive determination of Cr(VI) is of great importance as this is one of the most toxic heavy metal ions in the environment. In this work, a metal–organic framework (MOF) material, UIO-66 (University of Oslo, UIO), was introduced for the first time to develop a composite substrate, UIO-66/Ag/TiO2, for the sensitive SERS detection of Cr(VI) in water. The composition, morphology, crystal structure and optical property of the UIO-66/Ag/TiO2 were characterized by SEM, XRD, EDX, UV-Vis and Raman spectroscopy. The control experiment revealed the introduction of UIO-66 and TiO2 can improve the adsorption to Cr ions and thus greatly enhance the SERS signal of Cr(VI) on this composite substrate. The SERS signal can also be tuned by changing the dosage of TiO2. Under optimized conditions, UIO-66/Ag/TiO2 was used to detect Cr(VI) in water with different concentrations, which showed high sensitivity and good stability. The SERS signals showed a linear increase as the concentration of Cr(VI) increases from 5 × 10−9 M to 5 × 10−6 M. The detection limit was 5 nM, which was lower than the safe drinking water standard of the US Environmental Protection Agency (1 μM). Detection of Cr(VI) in the range of 1 × 10−7 M to 5 × 10−6 M in real lake water was also achieved. These results demonstrate the great potential of UIO-66/Ag/TiO2 composites as SERS substrates for the trace determination of Cr(VI) in the environmental field.
      Citation: Chemosensors
      PubDate: 2023-05-24
      DOI: 10.3390/chemosensors11060315
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 316: Near-Infrared Fluorescence Probe for
           Visualizing Fluctuations of Peroxynitrite in Living Cells and Inflammatory
           Mouse Models

    • Authors: Shuchun Qin, Yiming Ran, Yitian He, Xiaoyan Lu, Jiamin Wang, Weili Zhao, Jian Zhang
      First page: 316
      Abstract: Inflammation is a vital protective response in living systems and closely related to various diseases. As a member of the reactive oxygen species (ROS) family, peroxynitrite (ONOO−) is involved in the organism’s inflammatory process and considered as an important biomarker of inflammation. Therefore, the construction of a simple, rapid, and sensitive tool for detecting ONOO− is of great importance for the diagnosis of inflammation. In this study, we constructed the new near-infrared fluorescence probe BDP-ENE-S-Py+ based on BODIPY dye, which has the advantages of fast response speed (2 min), good selectivity, and a high signal-to-noise ratio. Moreover, the probe had a good linear relationship (LOD = 120 nM) when the ONOO− concentration was 10–35 µM. In addition, BDP-ENE-S-Py+ could detect exogenous ONOO− in liver cancer cells without interference from other reactive oxygen species and visualize the fluctuations in ONOO− concentrations in cells. More importantly, BDP-ENE-S-Py+ was able to track the upregulation of ONOO− content in a mouse model of peritonitis induced by LPS. This work demonstrated that the near-infrared fluorescent probe for visualizing ONOO− level fluctuations could provide a promising tool for inflammation-related studies.
      Citation: Chemosensors
      PubDate: 2023-05-24
      DOI: 10.3390/chemosensors11060316
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 317: The Role of Nano-Sensors in Breath
           Analysis for Early and Non-Invasive Disease Diagnosis

    • Authors: Nefeli Lagopati, Theodoros-Filippos Valamvanos, Vaia Proutsou, Konstantinos Karachalios, Natassa Pippa, Maria-Anna Gatou, Ioanna-Aglaia Vagena, Smaragda Cela, Evangelia A. Pavlatou, Maria Gazouli, Efstathios Efstathopoulos
      First page: 317
      Abstract: Early-stage, precise disease diagnosis and treatment has been a crucial topic of scientific discussion since time immemorial. When these factors are combined with experience and scientific knowledge, they can benefit not only the patient, but also, by extension, the entire health system. The development of rapidly growing novel technologies allows for accurate diagnosis and treatment of disease. Nanomedicine can contribute to exhaled breath analysis (EBA) for disease diagnosis, providing nanomaterials and improving sensing performance and detection sensitivity. Through EBA, gas-based nano-sensors might be applied for the detection of various essential diseases, since some of their metabolic products are detectable and measurable in the exhaled breath. The design and development of innovative nanomaterial-based sensor devices for the detection of specific biomarkers in breath samples has emerged as a promising research field for the non-invasive accurate diagnosis of several diseases. EBA would be an inexpensive and widely available commercial tool that could also be used as a disease self-test kit. Thus, it could guide patients to the proper specialty, bypassing those expensive tests, resulting, hence, in earlier diagnosis, treatment, and thus a better quality of life. In this review, some of the most prevalent types of sensors used in breath-sample analysis are presented in parallel with the common diseases that might be diagnosed through EBA, highlighting the impact of incorporating new technological achievements in the clinical routine.
      Citation: Chemosensors
      PubDate: 2023-05-24
      DOI: 10.3390/chemosensors11060317
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 318: Molecularly Imprinted Plasmonic Sensors
           for the Determination of Environmental Water Contaminants: A Review

    • Authors: Patrícia Rebelo, Isabel Seguro, Henri P. A. Nouws, Cristina Delerue-Matos, João G. Pacheco
      First page: 318
      Abstract: The scarcity of clean water leads to the exploration of the possibility of using treated wastewater. However, monitoring campaigns have proven the presence of emerging contaminants, such as pharmaceuticals, pesticides and personal care products, not only in trace amounts. Various analytical methodologies have been developed over the last years for the quantification of these compounds in environmental waters. Facing the need to achieve a higher sensitivity, fast response and practical use via miniaturization, the potential of plasmonic sensors has been explored. Through the introduction of molecularly imprinted polymers (MIPs) as recognition elements, MIP-based plasmonic sensors seem to be a good alternative for monitoring a wide range of analytes in water samples. This work attempts to provide a general overview of this form of sensor, which has been reported as being able to sense different contaminants in waters using surface plasmon resonance (SPR) and surface-enhanced Raman-scattering (SERS) techniques. Particular emphasis is given to the fabrication/recognition procedure, including the preparation of MIPs and the use of metals and nanomaterials to increase the performance characteristics of the sensors.
      Citation: Chemosensors
      PubDate: 2023-05-24
      DOI: 10.3390/chemosensors11060318
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 319: Transparent and High-Performance
           Extended Gate Ion-Sensitive Field-Effect Transistors Using Electrospun
           Indium Tin Oxide Nanofibers

    • Authors: Yeong-Ung Kim, Won-Ju Cho
      First page: 319
      Abstract: Herein, we propose a transparent high-performance extended-gate ion-sensitive field-effect transistor (EG-ISFET) using an electrospun indium-tin-oxide (ITO) nanofiber sensing membrane with a high specific surface area. Electrospinning is a simple and effective technique for forming nanofibers. Nevertheless, one-step calcination, such as conventional thermal annealing or microwave annealing, cannot sufficiently eliminate the inherent defects of nanofibers. In this study, we efficiently removed residual polymers and internal impurities from nanofibers via a two-step calcination process involving combustion and microwave annealing. Moreover, Ar plasma treatment was performed to improve the electrical characteristics of ITO nanofibers. Conformally coated thin-film sensing membranes were prepared as a comparative group and subjected to the same calcination conditions to verify the effect of the nanofiber sensing membrane. The characteristics of the ITO nanofiber and ITO thin-film sensing membranes were evaluated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), optical transmittance, and conductivity. Moreover, the sensor operation of the EG-ISFETs is evaluated in terms of sensitivity and non-ideal behaviors. The optimized process improves the sensor characteristics and sensing membrane quality. Therefore, the ITO nanofiber sensing membrane improves the sensitivity and stability of the EG-ISFET, suggesting its applicability as a high-performance biochemical sensor.
      Citation: Chemosensors
      PubDate: 2023-05-25
      DOI: 10.3390/chemosensors11060319
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 320: Effect of Nanoparticle Interaction on
           Structural, Conducting and Sensing Properties of Mixed Metal Oxides

    • Authors: Leonid I. Trakhtenberg, Maria I. Ikim, Olusegun J. Ilegbusi, Vladimir F. Gromov, Genrikh N. Gerasimov
      First page: 320
      Abstract: This review analyzes the studies published, mainly in the last 10–15 years, on the synthesis, structure, and sensor properties of semiconductor nanocomposites. Particular attention is paid to the interaction between nanoparticles of the sensitive layer, and its effect on the structure, sensitivity, and selectivity of semiconductor sensor systems. Various mechanisms of interaction between nanoparticles in metal oxide composites are considered, including the incorporation of metal ions of one component into the structure of another, heterocontacts between different nanoparticles, and core–shell systems, as well as their influence on the characteristics of gas sensors. The experimental data and studies on the modeling of charge distribution in semiconductor nanoparticles, which determine the conductivity and sensor effect in one- and two-component systems, are also discussed. It is shown that the model which considers the interactions of nanoparticles best describes the experimental results. Some mechanisms of detection selectivity are considered in the conclusion.
      Citation: Chemosensors
      PubDate: 2023-05-26
      DOI: 10.3390/chemosensors11060320
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 321: Additional Enhancement of
           Surface-Enhanced Raman Scattering Spectra of Myoglobin Precipitated under
           Action of Laser Irradiation on Self-Assembled Nanostructured Surface of Ag

    • Authors: Irina A. Boginskaya, Ekaterina A. Slipchenko, Marina V. Sedova, Julia Yu. Zvyagina, Alexander D. Maximov, Aleksandr S. Baburin, Ilya A. Rodionov, Alexander M. Merzlikin, Ilya A. Ryzhikov, Andrey N. Lagarkov
      First page: 321
      Abstract: The modifications of the microstructure of myoglobin deposited onto SERS-active Ag-based substrates by drying a drop of aqueous solution with and without laser irradiation and the corresponding surface-enhanced Raman scattering (SERS) spectra are studied. It is shown that drying with laser irradiation leads to the formation of protein aggregates of various types, including crystal-like aggregates. It is also shown that after such drying, the aggregates generally have SERS spectra characterized by a change in the position of the vibration bands and the ratios of their amplitudes compared to the spectra of proteins dried without additional treatment. In particular, parts of the SERS spectra of aggregates formed under laser irradiation are characterized by an additional enhancement (up to 100×) compared to the SERS spectra of myoglobin dried in air at room temperature. The crystallization processes were modeled using the results of atomic force microscopy morphology studies of dried myoglobin on the SERS-active substrates to determine the conditions under which crystal-like aggregates start to grow at surface irregularities, specifically those with a volume close to that of the critical-size nucleus, and where the lowest energy of formation occurs. A correlation is established between surface irregularities, the amplitude, and the change in the SERS spectra during the drying of a myoglobin solution sample on a nanostructured Ag-based surface.
      Citation: Chemosensors
      PubDate: 2023-06-01
      DOI: 10.3390/chemosensors11060321
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 322: Synthesis of Flower-like ZnO and Its
           Enhanced Sensitivity towards NO2 Gas Detection at Room Temperature

    • Authors: Zhicheng Cai, Jiho Park, Sunghoon Park
      First page: 322
      Abstract: A flower-like ZnO was successfully synthesized via a simple chemical precipitation method at room temperature (RT) in distilled water, without the use of any catalysts or substrates. The sample’s structure was analyzed using various techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (FETEM), and X-ray photoelectron spectroscopy (XPS), which confirmed its hexagonal structure. UV–visible optical absorption measurements also revealed the presence of UV absorption at 365 nm. A reasonable growth mechanism for the formation of flower-like ZnO was proposed based on these analyses. The response of the sample to low concentrations of NO2 (1 ppm) was evaluated at different calcination temperatures, and the results showed that the best response was achieved when the sample was calcined at 600 °C. The flower-like ZnO sample labeled as 6ZnO showed the highest response of 54.18 when exposed to 1 ppm of NO2 gas at RT. Additionally, 6ZnO exhibited good response and recovery properties of 11 s and 93 s, respectively, at low concentrations of NO2 at 1 ppm. The gas sensing mechanism and the mechanism of the enhanced gas response of the flower-like ZnO are discussed.
      Citation: Chemosensors
      PubDate: 2023-06-01
      DOI: 10.3390/chemosensors11060322
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 323: Polymeric Composite including Magnetite
           Nanoparticles for Hydrogen Peroxide Detection

    • Authors: Maria Roniele Felix Oliveira, Pilar Herrasti, Roselayne Ferro Furtado, Airis Maria Araújo Melo, Carlucio Roberto Alves
      First page: 323
      Abstract: The combination of a biopolymer and a conductive polymer can produce new materials with improved physico-chemical and morphological properties that enhance their use as sensors. Magnetite nanoparticles (MN) can be further introduced to these new matrices to improve the analytical performance. This study aimed to evaluate the electrocatalytic response of nanocomposites formed by the introduction of MN to polypyrrole (PPy) doped in the presence of cashew gum polysaccharide (CGP) and in the presence of carboxymethylated cashew gum polysaccharide (CCGP). Characterization of the nanocomposites was carried out via transmission electron microscopy (TEM) and infrared spectroscopy (FTIR) and showed that the absorption band of the blend was shifted to a higher frequency in the nanocomposites, indicating the intermolecular interaction between the blend and nanoparticles. The electrocatalytic performance of the nanocomposites was evaluated by applying a constant potential of −0.7 V with successive additions of H2O2 (1 mmol L−1) in 10 mmol L−1 phosphate buffer under agitation at pH 7.5. The nanocomposite formed by the introduction of MN to polypyrrole doped with cashew gum polysaccharide (PPy(cgp)–MN) displayed excellent electrocatalytic surface properties, with high H2O2 specificity, a linear response (R2 = 0.99), high sensitivity (0.28 µmol L−1), and a low H2O2 detection limit (0.072 mmol L−1).
      Citation: Chemosensors
      PubDate: 2023-06-01
      DOI: 10.3390/chemosensors11060323
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 324: Dilute-and-Shoot-Liquid
           Chromatography-Quadrupole Time of Flight-Mass Spectrometry for Pteridine
           Profiling in Human Urine and Its Association with Different Pathologies

    • Authors: Claudia Giménez-Campillo, Marta Pastor-Belda, Natalia Arroyo-Manzanares, Natalia Campillo, Blanca del Val Oliver, José Zarauz-García, Luis Sáenz, Pilar Viñas
      First page: 324
      Abstract: Pteridines are a group of compounds synthesised by many living organisms that are involved in the metabolism of many cofactors and vitamins. Their concentration in biological fluids may be altered by various pathologies such as cancer or inflammatory bowel disease, urine being the main route of excretion. In this study, three lumazines and ten pterins were analysed in their native oxidation state using high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Their high concentration in urine samples and their good ionisation behaviour allow the use of the dilute-and-shoot method by simple filtration of the urine prior to chromatographic analysis. The final method offers excellent linearity, sensitivity and precision parameters, and a total of 135 urine samples were analysed from patients with some relevant information such as faecal calprotectin (FCP) levels, common diseases such as diabetes, hypertension and dyslipidaemia and immunological diseases such as inflammatory bowel disease (IBD). The pteridine profile was related to FCP levels without showing any correlation. In addition, pteridine levels were compared between healthy subjects and IBD, diabetic, hypertensive and dyslipidaemic patients, and significant differences were found between the two groups for some of the pteridines.
      Citation: Chemosensors
      PubDate: 2023-06-01
      DOI: 10.3390/chemosensors11060324
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 325: High Sensitivity Low-Temperature
           Hydrogen Sensors Based on SnO2/κ(ε)-Ga2O3:Sn Heterostructure

    • Authors: Aleksei Almaev, Nikita Yakovlev, Viktor Kopyev, Vladimir Nikolaev, Pavel Butenko, Jinxiang Deng, Aleksei Pechnikov, Petr Korusenko, Aleksandra Koroleva, Evgeniy Zhizhin
      First page: 325
      Abstract: The structural and gas-sensitive properties of n-N SnO2/κ(ε)-Ga2O3:Sn heterostructures were investigated in detail for the first time. The κ(ε)-Ga2O3:Sn and SnO2 films were grown by the halide vapor phase epitaxy and the high-frequency magnetron sputtering, respectively. The gas sensor response and speed of operation of the structures under H2 exposure exceeded the corresponding values of single κ(ε)-Ga2O3:Sn and SnO2 films within the temperature range of 25–175 °C. Meanwhile, the investigated heterostructures demonstrated a low response to CO, NH3, and CH4 gases and a high response to NO2, even at low concentrations of 100 ppm. The current responses of the SnO2/κ(ε)-Ga2O3:Sn structure to 104 ppm of H2 and 100 ppm of NO2 were 30–47 arb. un. and 3.7 arb. un., correspondingly, at a temperature of 125 °C. The increase in the sensitivity of heterostructures at low temperatures is explained by a rise of the electron concentration and a change of a microrelief of the SnO2 film surface when depositing on κ(ε)-Ga2O3:Sn. The SnO2/κ(ε)-Ga2O3:Sn heterostructures, having high gas sensitivity over a wide operating temperature range, can find application in various fields.
      Citation: Chemosensors
      PubDate: 2023-06-01
      DOI: 10.3390/chemosensors11060325
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 326: Au Nanoparticles on
           4-Thiophenol-Electrodeposited Carbon Surfaces for the Simultaneous
           Detection of 8-Hydroxyguanine and Guanine

    • Authors: Niloufar Soltani, Qusai Hassan, Meissam Noroozifar, Kagan Kerman
      First page: 326
      Abstract: In this proof-of-concept study, gold nanoparticles (AuNPs) were immobilized on glassy carbon electrode (GCE) surfaces using a surface-anchored diazonium salt of 4-aminothiophenol (GCE-Ph-S-AuNPs). X-ray photoelectron spectroscopy (XPS) studies confirmed the attachment of the AuNPs via 4-thiophenol onto the surface of the modified electrode. Differential pulse voltammetry (DPV) was performed for the simultaneous determination of guanine (G) and 8-hydroxyguanine (8-OH-G). The calibration curves were linear up to 140 µM and 60 µM with a limit of detection of 0.02 µM and 0.021 µM for G and 8-OH-G, respectively. Moreover, chronoamperometric studies were carried out for the determination of diffusion coefficients of 8-OH-G and G. The GCE-Ph-S-AuNPs were also applied in genomic DNA-spiked samples for the determination of G and 8-OH-G with recovery rates between 98.5% and 103.3%. The novel electrochemical surface provided a potential platform for the sensitive detection of 8-OH-G related to oxidative stress-induced DNA damage in clinical studies.
      Citation: Chemosensors
      PubDate: 2023-06-02
      DOI: 10.3390/chemosensors11060326
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 327: Spray-On Colorimetric Sensors for
           Distinguishing the Presence of Lead Ions

    • Authors: Priyanka Shiveshwarkar, Justyn Jaworski
      First page: 327
      Abstract: Sprayable stimuli-responsive material coatings represent a new class of detection system which can be quickly implemented to transform a surface into a color-responsive sensor. In this work, we describe a dipicolylamine-terminated diacetylene-containing amphiphile formulation for spray coating on to a simple paper substrate to yield disposable test strips that can be used to detect the presence of lead ions in solution. We find the response to be very selective to only lead ions and that the sensitivity can be modulated by altering the UV curing time after spraying. Sensitive detection to at least 0.1 mM revealed a clear color change from a blue to red phase. This represents the first demonstration of a spray-on sensor system capable of detection of lead ions in solution.
      Citation: Chemosensors
      PubDate: 2023-06-02
      DOI: 10.3390/chemosensors11060327
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 328: Plasma-Sputtered Growth of Ni-Pd
           Bimetallic Nanoparticles on Carbon Nanotubes for Toluene Sensing

    • Authors: Selene Acosta, Juan Casanova-Chafer, Eduard Llobet, Axel Hemberg, Mildred Quintana, Carla Bittencourt
      First page: 328
      Abstract: The properties of carbon nanotubes (CNTs) can be effectively tailored by decorating their surface with metal nanoparticles. For the decoration, first plasma functionalization is used to add oxygen chemical groups to the CNTs surface. Afterwards, the Ox-CNTs are decorated with Ni-Pd bimetallic nanoparticles using plasma sputtering deposition, a clean, fast, and environmentally friendly functionalization method. The grafted oxygen groups serve as nucleation sites for the growth of the bimetallic nanoparticles. Finally, the Ni-Pd nanoparticle-decorated CNTs are assessed as a sensing layer for the detection of toluene.
      Citation: Chemosensors
      PubDate: 2023-06-02
      DOI: 10.3390/chemosensors11060328
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 329: A Sensor for Electrochemical pH
           Monitoring Based on Laser-Induced Graphene Modified with Polyfolate

    • Authors: Vytautas Žutautas, Romualdas Trusovas, Aivaras Sartanavičius, Karolis Ratautas, Algirdas Selskis, Rasa Pauliukaite
      First page: 329
      Abstract: A laser-induced graphene (LIG) modified with chitosan (Chit) and conducting polymer polyfolate (PFA) was used as a base to develop a flat and flexible pH sensor. LIGs were formed using two different irradiation wavelengths of 355 nm and 532 nm. Depending on the wavelengths, the obtained electrodes were named LIG355 and LIG532. Microscopic imaging revealed that the bare LIG electrode surface had rough structures after laser treatment giving hydrophilic properties, and that PFA forms fibre-like structures on Chit coated LIG. Electrochemical investigation with the redox probe demonstrated that diffusion is a limiting process at the bare and modified LIG electrodes. A capacitive behaviour was observed from electrochemical impedance spectra at bare electrodes, showing a rather rough interface at LIG355 but a microporous one at LIG532. The developed flat and flexible electrode was sensitive to pH in the region from 6.0 to 9.0. In the studied pH range, the sensitivity was 27.86 ± 0.81 for PFA/Chit/LIG355 and 30.32 ± 0.50 mV/pH for PFA/Chit/LIG532 with moderate stability for a period of more than two months.
      Citation: Chemosensors
      PubDate: 2023-06-02
      DOI: 10.3390/chemosensors11060329
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 330: Gold Nanocluster-Based Fluorescent
           Sensor Array for Antibiotic Sensing and Identification

    • Authors: Mengjiao Mo, Haoyi Yuan, Jingyu Zhang, Jian Wang, Ying Liu, Juanjuan Peng, Lingzhi Zhao
      First page: 330
      Abstract: Antibiotic contamination has become a serious global problem due to abuse and misuse. Therefore, it is important to develop an efficient detection method to monitor the rational use of antibiotics. In this study, fluorescent gold nanoclusters with 11-mercaptoundecanoic acid as ligands (MUA-AuNCs) were synthesized by a one-step method firstly. Rare earth ions (Re3+) can enhance the fluorescence of MUA-AuNCs through inducing the aggregation of MUA-AuNCs, but antibiotics decrease the fluorescence of the Re3+-MUA-AuNCs to different degrees through coordination with Re3+ and competitive absorption with AuNCs. Therefore, a sensor array was obtained on the basis of the above mechanism, which can detect and discriminate six different antibiotics with a detection range from 40 to 300 μM. A 100% correct classification was achieved. The fluorescent sensor array showed high selectivity for tetracycline antibiotics and good anti-interference performance was demonstrated. Combined with pattern recognition methods, the proposed sensor array can be used for the discrimination of different antibiotics and binary antibiotic mixtures. Furthermore, the excellent performance of this sensor array in quantitation and blind sample recognition further validates its potential for practical applications.
      Citation: Chemosensors
      PubDate: 2023-06-03
      DOI: 10.3390/chemosensors11060330
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 331: Development of Sensitive Electrochemical
           Sensor Based on Chitosan/MWCNTs-AuPtPd Nanocomposites for Detection of
           Bisphenol A

    • Authors: En Han, Yingying Pan, Lei Li, Yuan Liu, Yuan Gu, Jianrong Cai
      First page: 331
      Abstract: An electrochemical sensor based on AuPtPd trimetallic nanoparticles functionalized multi-walled carbon nanotubes coupled with chitosan modified glassy carbon electrode (GCE/CS/MWCNTs-AuPtPd) was proposed for the rapid detection of bisphenol A (BPA). AuPtPd trimetallic nanoparticles were first assembled on MWCNTs to obtain MWCNTs-AuPtPd nanocomposite. Then, the MWCNTs-AuPtPd was further dispersed on the chitosan-modified electrode surface to fabricate the GCE/CS/MWCNTs-AuPtPd sensor. Due to the superior catalytic properties of MWCNTs-AuPtPd and the good film formation of chitosan, the constructed sensor displayed good performances for BPA detection. The structural morphology of CS/MWCNTs-AuPtPd was characterized in many ways, such as SEM, TEM and UV-vis. The designed sensor showed a linear relationship in concentration range from 0.05 to 100 µM for BPA detecting, and the detection limit was 1.4 nM. The GCE/CS/MWCNTs-AuPtPd was further used to realize the detection of BPA in food samples, and the recovery was between 94.4% and 103.6%. Those results reflected that the electrochemical sensor designed by CS/MWCNTs-AuPtPd nanocomposites was available, which could be used for the monitoring of food safety.
      Citation: Chemosensors
      PubDate: 2023-06-03
      DOI: 10.3390/chemosensors11060331
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 332: A ‘Turn-On’ Carbamazepine
           Sensing Using a Luminescent SiO2/-(CH2)3NH2/-C6H5 + Rh6G System

    • Authors: Halyna Yankovych, Erika Dutková, Viktoriia Kyshkarova, Miroslava Vaclavikova, Inna Melnyk
      First page: 332
      Abstract: Carbamazepine is a crucial medication used to treat nervous system disorders, and its low level of absorption in the human body suggests that a significant amount of it may be present in sewage water. Consequently, this pioneering research deals with the synthesis and application of a luminescent sensor based on rhodamine 6 G-modified bifunctional silica particles for the determination of carbamazepine. The sensing material was fabricated in one step by the sol–gel technique and the dye was adsorbed onto the surface from an alcohol solution. The composition, morphology and size of functionalized silica particles were determined by physico-chemical methods. The material’s features provide the possibility of its application as a sensing material for carbamazepine determination at a variety of concentrations. The sensor possesses a linear response towards carbamazepine in the concentration range of 0.8–200.0 μM with a limit of detection (LOD) of 17.9 μM and a limit of quantification (LOQ) of 59.7 μM and has demonstrated reliable quantification over a wide range of concentrations, from therapeutic to high fatal concentrations. Additionally, the sensing mechanism has been proposed, which involves the formation of hydrogen bonding between carbamazepine and Rhodamine 6G immobilized bifunctional silica particles.
      Citation: Chemosensors
      PubDate: 2023-06-04
      DOI: 10.3390/chemosensors11060332
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 333: Recent Progress in Fluorescent Probes
           for the Detection and Research of Hydrogen Sulfide in Cells

    • Authors: Weier Liang, Yong Zhang, Shaoqing Xiong, Dongdong Su
      First page: 333
      Abstract: Hydrogen sulfide (H2S) is a gaseous signaling molecule that plays an important role in regulating various physiological activities in biological systems. As the fundamental structural and functional unit of organisms, cells are closely related to the homeostasis of their internal environment. The levels of H2S in different organelles maintain a certain balance, and any disruption of this balance will lead to various functional abnormalities that affect the health of organisms. Fluorescent imaging technology provides unique merits, such as simplicity, non-invasiveness, and real-time monitoring, and has become a powerful approach for the detection of molecules in biological systems. Based on the special physicochemical properties of H2S, numerous H2S-specific fluorogenic probes have been designed with different recognition mechanisms that enable rapid and accurate detection of H2S in cells. Therefore, this review briefly illustrates the design strategies, response principles, and biological applications of H2S-specific fluorescent probes and aims to provide relevant researchers with insight for future research.
      Citation: Chemosensors
      PubDate: 2023-06-04
      DOI: 10.3390/chemosensors11060333
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 334: N-Doped Graphene and Its Derivatives as
           Resistive Gas Sensors: An Overview

    • Authors: Ali Mirzaei, Somalapura Prakasha Bharath, Jin-Young Kim, Krishna K. Pawar, Hyoun Woo Kim, Sang Sub Kim
      First page: 334
      Abstract: Today, resistance gas sensors which are mainly realized from metal oxides are among the most used sensing devices. However, generally, their sensing temperature is high and other materials with a lower operating temperature can be an alternative to them. Graphene and its derivatives with a 2D structure are among the most encouraging materials for gas-sensing purposes, because a 2D lattice with high surface area can maximize the interaction between the surface and gas, and a small variation in the carrier concentration of graphene can cause a notable modulation of electrical conductivity in graphene. However, they show weak sensing performance in pristine form. Hence, doping, and in particular N doping, can be one of the most promising strategies to enhance the gas-sensing features of graphene-based sensors. Herein, we discuss the gas-sensing properties of N-doped graphene and its derivatives. N doping can induce a band gap inside of graphene, generate defects, and enhance the conductivity of graphene, all factors which are beneficial for sensing studies. Additionally, not only is experimental research reviewed in this review paper, but theoretical works about N-doped graphene are also discussed.
      Citation: Chemosensors
      PubDate: 2023-06-05
      DOI: 10.3390/chemosensors11060334
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 335: Micro-Magnetofluidic System for Rare
           Cell Analysis: From Principle to Translation

    • Authors: Kangfu Chen, Zongjie Wang
      First page: 335
      Abstract: Rare cells play essential roles in the initiation and progression of diseases and therefore their analysis is of great interest. The micro-magnetofluidic system is one of the emerging platforms that have been proposed for the rapid, sensitive, and cost-effective analysis of rare cells. Given its unprecedented throughput, micro-magnetofluidic systems have attracted substantial research interest in the last decade—multiple designs have been proposed, validated, and even advanced to the stage of clinical trials. This mini review aims to provide a timely summary of the relevant progress in the field thus far. We reviewed the concepts and realizations of micro-magnetofluidic devices based on the interaction between nanoparticles and on-chip micro-magnets. Their real-world applications in rare cell analysis were also highlighted and explained. In addition, we discussed the major challenges in the development and translation of micro-magnetofluidic into the clinic, including multi-marker capability and large-scale manufacturability.
      Citation: Chemosensors
      PubDate: 2023-06-06
      DOI: 10.3390/chemosensors11060335
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 336: Ammonia Sensor Based on Co2+/SCN−
           Modified Core-Shell MCM-41 for Rapid Naked-Eye Colorimetric Detection

    • Authors: Songtao Liu, Kaixin Wei, Fuqiang Cheng, Yongsheng Li, Min Xue
      First page: 336
      Abstract: Mesoporous silica materials have been widely used as gas adsorbents due to their excellent adsorption ability, large specific surface area, simple preparation process, and convenient functionalization. In this study, a core–shell mesoporous material MCM-41@SiO2 was synthesized and functionalized by CoCl2, and subsequently KSCN, to prepare an ammonia adsorbent. The adsorbent was proved to possess high surface area, good sphericity, uniform size, good dispersibility, and high adsorption capability following DLS, SEM, TEM, and a static adsorption study. Moreover, the successful functionalization and thermal stability were confirmed by FT-IR, XPS, and TGA. The material was then used to fabricate a glass tube sensor for the rapid naked-eye detection of ammonia gas. The sensor showed good performance in terms of sensing speed, selectivity, accuracy, and reusability. Within 5 s, NH3 could be detected by the discoloration, and a wide NH3 concentration from 20 to 1000 ppm could be detected. It also showed a good linear relationship between discoloration length and ammonia concentration. A reversible color change from blue to yellow indicated the presence of NH3, which was attributed to the formation and disassembly of ammonia-containing complex [Co(NH3)6(NCS)2]. With fast adsorption, naked-eye sensing properties, and good selectivity, the sensor holds good promise for indoor NH3 sensing and other more complicated situations.
      Citation: Chemosensors
      PubDate: 2023-06-06
      DOI: 10.3390/chemosensors11060336
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 337: Graphene-Based Electrodes for Monitoring
           of Estradiol

    • Authors: Auwal M. Musa, Janice Kiely, Richard Luxton, Kevin C. Honeychurch
      First page: 337
      Abstract: This study explores the potential use of graphene-based electrodes in the electrochemical determination of estradiol using amperometric techniques as a simple, enzyme-free approach. Graphene, a carbon-based nanomaterial, has been extensively investigated in materials science as a sensing material. Its remarkable properties, such as its high electron mobility and conductivity, robust mechanical characteristics, and good surface-to-volume ratio, have led to its adoption in numerous applications, including electrochemical sensing. Estradiol is a crucial sex hormone that affects metabolism and reproduction. However, excessive amounts may disrupt endocrine functions. Electrochemical sensors suffer from electrode fouling, leading to passivation that ultimately affects performance. We exploit the inherent properties of various types of graphene-based electrodes, including graphene screen-printed electrodes (GHSPE), electrochemically exfoliated graphene-modified electrodes (EEFGHSPE), and 3D graphene foam screen-printed electrodes (3D-GFSPE), for the amperometric studies. The electrochemical properties and structural characteristics of these sensors are evaluated using cyclic voltammetry and scanning electron microscopy. The analytical performance of these sensors is at an applied potential of +0.65 V (vs. Ag/AgCl) over the concentration range 0.83 to 4.98 μM estradiol. Sensitivities of 0.151 µAµM−1 cm−2, 0.429 µAµM−1 cm−2, and 0.273 µA µM−1 cm−2, with detection limits of 0.0041 µM, 0.097 µM, and 0.018 µM (S/N = 3), are found for GHPSPE, 3D-GFSPE and EEFGHSPE, respectively. The possibility of amperometrically determining the estradiol levels in a potable tap water sample are then investigated over the concentration range 0.83–4.98 µM.
      Citation: Chemosensors
      PubDate: 2023-06-06
      DOI: 10.3390/chemosensors11060337
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 338: Laser-Induced Graphene on Optical Fibre:
           Towards Simple and Cost-Effective Electrochemical/Optical Lab-on-Fibre

    • Authors: Laura L. Ferreira, Rafael A. Ribeiro, António J. S. Fernandes, Florinda M. Costa, Carlos Marques, Nuno F. Santos
      First page: 338
      Abstract: A 3D graphene foam made of interconnected multilayer graphene flakes was produced on optical fibres (OF) by laser-induced transformation of a polyimide (PI) film coated on the OF cladding. This material, known as laser-induced graphene (LIG), was explored in the electrochemical detection and quantification of dopamine (DA) at physiologically relevant concentrations in the presence of the most relevant interfering molecules in biological fluids, ascorbic acid (AA) and uric acid (UA). The measured limit of detection is 100 nM, the linear range is 0.1 to 5.0 μM and a maximum sensitivity of 5.0 µA µM−1 cm−2 was obtained for LIG decorated with Pt nanoparticles (NPs). Moreover, immunity to AA and UA interference and to fouling was attained by decorating the LIG electrode with Pt NPs and coating it with Nafion. These figures of merit underline the potential of these sensors for the quantification of physiologically relevant concentrations of DA in biological fluids, paving the way for the development of hybrid electrochemical/optical sensing actuating platforms in a lab-on-fibre configuration, with relevant applications in biomedical engineering. The advantages of this hybrid arrangement include the possibility of in situ counterproofing, extended measuring ranges, photoelectrochemical detection and the probing of inaccessible places. This elegant approach can also provide a simple and cost-effective way to fabricate biomedical devices with extended functionality, such as medical optical probes with added electrochemical capabilities and optogenetics combined with local electrochemical detection, among others.
      Citation: Chemosensors
      PubDate: 2023-06-07
      DOI: 10.3390/chemosensors11060338
      Issue No: Vol. 11, No. 6 (2023)
  • Chemosensors, Vol. 11, Pages 259: Enantioanalysis of Leucine in Whole
           Blood Samples Using Enantioselective, Stochastic Sensors

    • Authors: Raluca-Ioana Stefan-van Staden, Oana-Raluca Musat
      First page: 259
      Abstract: Enantioanalysis of amino acids became a key factor in the metabolomics of cancer. As a screening method, it can provide information about the state of health of patients. The main purpose of the study is to develop a highly reliable enantioanalysis method for the determination of D-, and L-leucine in biological samples in order to establish their role as biomarkers in the diagnosis of breast cancer. Two enantioselective stochastic sensors based on N-methyl-fullero-pyrrolidine in graphite and graphene nanopowder pastes were designed, characterized, and validated for the enantioanalysis of leucine in whole blood. Different signatures were recorded for the biomarkers when the stochastic sensors were used, proving their enantioselectivity. In addition, limits for detection on the order of ag L−1 were recorded for each of the enantiomers of leucine when the proposed enantioselective stochastic sensors were used. The wide linear concentration ranges facilitated the assay of the L-leucine in healthy volunteers, and also in patients confirmed with breast cancer. Recoveries of one enantiomer in the presence of the other enantiomer in whole blood samples, higher than 96.50%, proved that the enantioanalysis of enantiomers can be performed reliably from whole blood samples.
      Citation: Chemosensors
      PubDate: 2023-04-22
      DOI: 10.3390/chemosensors11050259
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 260: Porous Copper Oxide Thin Film Electrodes
           for Non-Enzymatic Glucose Detection

    • Authors: Soledad Carinelli, Pedro A. Salazar-Carballo, Julio Ernesto De la Rosa Melián, Francisco García-García
      First page: 260
      Abstract: The present work describes novel copper oxide thin film-modified indium tin oxide electrodes prepared by magnetron sputtering and their application for glucose sensing. Copper oxide-modified sensors were characterized by electrochemical techniques, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The deposited thin film (of about 400 nm of thickness) consisted of Cu2O/CuO nanocolumns of ca. 80 nm in diameter. After optimizing the main experimental parameters, the electrodes showed noteworthy electrocatalytic properties for glucose detection (sensitivity ca. 2.89 A M−1 cm−2 and limit of detection ca. 0.29 μM (S/N = 3)). The sensor showed negligible response against common electroactive species and other sugars. Finally, recovery experiments in commercial soda drinks and the determination of glucose content in different commercial drinks, such as soda, tea, fruit juices, and sports drinks, are described.
      Citation: Chemosensors
      PubDate: 2023-04-25
      DOI: 10.3390/chemosensors11050260
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 261: Electrocatalytic and
           Photoelectrocatalytic Sensors Based on Organic, Inorganic, and Hybrid
           Materials: A Review

    • Authors: Isabela Jasper, Tatiana Lima Valério, Vanessa Klobukoski, Camila Melo Pesqueira, Jonas Massaneiro, Luan Pereira Camargo, Luiz Henrique Dall’ Antonia, Marcio Vidotti
      First page: 261
      Abstract: Electrochemical sensors present a wide range of interesting applications in the areas of environmental, industrial, and chemical analysis. This review presents an overview of two types of sensors: electrocatalytic ones, which involve oxidation and reduction reactions through electron transfer, and photoelectrocatalytic ones, which involve a current response due to the incidence of light and redox reactions. Another point discussed was how these sensors’ detection capacity and behavior can be affected by several factors related to the material used to make the electrode. In this way, inorganic, organic, and hybrid materials were compared in electrocatalytic and photoelectrocatalytic sensors. The use of inorganic materials is interesting due to the fact of their abundance, low cost, and good electroactivity. Among organics, conductive polymers and carbonaceous materials are often cited due to the fact of their conductivity and their different possibilities for synthesis, being possible to mold their shape. Finally, hybrid materials unite these two classes, presenting different properties not found in a single substance.
      Citation: Chemosensors
      PubDate: 2023-04-27
      DOI: 10.3390/chemosensors11050261
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 262: Application of Molecularly Imprinted
           Microelectrode as a Promising Point-of-Care Biosensor for Alanine
           Aminotransferase Enzyme

    • Authors: Mostafa Ahmed Samy, Muhammed Abdel-Hamied Abdel-Tawab, Nour. T. Abdel-Ghani, Rasha M. El Nashar
      First page: 262
      Abstract: Alanine amino transaminase (ALT) is an enzyme that can be used as a biomarker for liver injury and other diseases. In this work, we report the development of the first microelectrode based on a molecularly imprinted pyruvate oxidase enzyme to be applied as an electrochemical biosensor for ALT detection. The biosensor is based on pyruvate oxidase enzyme (POx), imprinted using 4-aminophenol (functional monomer-on-platinum microelectrode modified (PME)) with platinum nanoparticles and 4-aminoantypirine (4-AAP)/sodium pyruvate as an electrochemical indicator. The operational conditions of the biosensor were optimized and characterized morphologically using scanning electron microscopy (SEM) and electrochemically using electrochemical impedance spectroscopy (EIS). The biosensor was found to have a fast response towards ALT within a linear range of 25–700 U/L and a limit of detection of 2.97 U/L. The biosensor did not exhibit cross-reactivity towards other tested enzymes, including nicotinamide adenine dinucleotide (Beta-NAD), catalase (CAT), glutathione peroxidase (GPx), and L-glutathione reduced (GSH) enzymes. The biosensor was efficiently applied for the assay of ALT in plasma samples; with recovery values ranging from 99.80–103.82% and RSD of values 0.27–2.01% and these results were found to be comparable to those of the reference diagnostic kits, without any need for complicated procedures or protein extraction. In addition to being highly sensitive, low cost, and portable, the use of microelectrodes allows the application of the proposed sensor for point-of-care diagnostics of liver function and online monitoring of ALT levels in hospitalized patients without the need for withdrawing samples, which indicates the promising applicability of the presented ALT sensor for point-of-care diagnostics.
      Citation: Chemosensors
      PubDate: 2023-04-27
      DOI: 10.3390/chemosensors11050262
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 263: Phosphorescent O2-Probes Based on
           Ir(III) Complexes for Bioimaging Applications

    • Authors: Mozhgan Samandarsangari, Ilya S. Kritchenkov, Daria O. Kozina, Anastasia D. Komarova, Marina V. Shirmanova, Sergey P. Tunik
      First page: 263
      Abstract: The design, synthesis, and investigation of new molecular oxygen probes for bioimaging, based on phosphorescent transition metal complexes are among the topical problems of modern chemistry and advanced bioimaging. Three new iridium [Ir(N^C)2(N^N)]+ complexes with cyclometallating 4-(pyridin-2-yl)-benzoic acid derivatives and different di-imine chelate ligands have been synthesized and characterized by mass spectrometry and NMR spectroscopy. The periphery of these complexes is decorated with three relatively small “double-tail” oligo(ethylene glycol) fragments. All these complexes exhibit phosphorescence; their photophysical properties have been thoroughly studied, and quantum chemical calculations of their photophysical properties were also performed. It turned out that the changes in the nature of the di-imine ligand greatly affected the character of the electronic transitions responsible for their emission. Two complexes in this series show the desired photophysical characteristics; they demonstrate appreciable quantum yield (14–15% in degassed aqueous solutions) and a strong response to the changes in oxygen concentration, ca. three-fold increase in emission intensity, and an excited state lifetime upon deaeration of the aqueous solution. The study of their photophysical properties in model biological systems (buffer solutions containing fetal bovine serum—FBS) and cytotoxicity assays (MTT) showed that these complexes satisfy the requirements for application in bioimaging experiments. It was found that these molecular probes are internalized into cultured cancer cells and localized mainly in mitochondria and lysosomes. Phosphorescent lifetime imaging (PLIM) experiments showed that under hypoxic conditions in cells, a 1.5-fold increase in the excitation state lifetime was observed compared to aerated cells, suggesting the applicability of these complexes for the analysis of hypoxia in biological objects.
      Citation: Chemosensors
      PubDate: 2023-04-28
      DOI: 10.3390/chemosensors11050263
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 264: Perovskite-Structured NiTiO3 Modified
           NiO Gas Sensor for Xylene Detection

    • Authors: Liyun Qin, Hongliang Gao, Fanli Meng
      First page: 264
      Abstract: Xylene gas is highly toxic, can irritate the skin, and is also very harmful to the body. Therefore, it is necessary to prepare sensors that can accurately detect xylene. In this paper, NiTiO3 nanoparticles were synthesized by the hydrothermal method and used to modify NiO, and a NiTiO3-modified NiO (NiTiO3-NiO) nanosheet material was successfully prepared. Its microstructure and internal composition were observed and analyzed by various characterization methods. When detecting 100 ppm xylene gas at the optimum temperature, comparing the response level of the NiTiO3-NiO sensor with that of a pure nickel oxide sensor, the former was 20 times that of the latter, and the sensitivity was greatly improved. In a 100 ppm xylene gas environment, the response level of the sensor reached 21, the minimum detection limit was 1 ppm, and the recovery time was 135.75 s. NiTiO3 is a perovskite-structured material, with many active sites and good catalytic properties that promote redox reactions.
      Citation: Chemosensors
      PubDate: 2023-04-29
      DOI: 10.3390/chemosensors11050264
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 265: Distinctive Labeling of Live Monocytes
           and Neutrophils with a Single Fluorescent Molecule

    • Authors: Songhui Kim, Masahiro Fukuda, Jung Yeol Lee, Young-Tae Chang, H. Shawn Je, Beomsue Kim
      First page: 265
      Abstract: (1) Background: a small-molecule fluorescent chemosensor, CDr20, tracks the resident macrophages based on the UGT1A7C activity in the brain, raising the possibility that additional immune cells expressing the UGT1A7C can be labeled with CDr20. (2) Methods: we applied CDr20 to various types of blood cells derived from hematopoietic organs (spleen and bone marrow) as well as peripheral blood to test the degree and selectivity of labeling of CDr20 in these cell types; (3) Results: CDr20 fluorescently labels monocytes/macrophages and neutrophils as a result of glucuronidation reaction (CDr20-Gluc), which is mediated with UGT1A7C. The selectivity of CDr20 labeling highly correlates with the Ugt1a7c expression level in immune cells. Moreover, CDr20-Gluc is exported from cells by a mechanism of how glucuronides within cells are excreted into extracellular space. Interestingly, the exportation of CDr20-Gluc is mainly observed in monocytes, potentially due to the monocyte-specific expression of ABCC transporters and this resulted in large differences in the degree of fluorescence retention in neutrophils (CDr20bright), compared to monocytes (CDr20dim) upon one hour of CDr20 incubation; (4) Conclusions: CDr20 can differentially label monocytes and neutrophils due to the variance in two different cellular enzymatic activities of UGT1A7C and ABCC. By using this property, CDr20 can be used to distinguish specific cell types within blood.
      Citation: Chemosensors
      PubDate: 2023-04-29
      DOI: 10.3390/chemosensors11050265
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 266: Simulating the Detection of Dioxin-like
           Pollutants with 2D Surface-Enhanced Raman Spectroscopy Using h-BNC

    • Authors: Raúl Alvarado, Nicolás Otero, Marcos Mandado, Nicolás Ramos-Berdullas
      First page: 266
      Abstract: The ability of 2D hybrid structures formed by boron, nitrogen and carbon atoms (h-BNCs) to act as potential substrates for the surface-enhanced Raman spectroscopy (SERS) detection of dioxin-like pollutants is theoretically analyzed. The strong confinement and high tunability of the electromagnetic response of the carbon nanostructures embedded within the h-BNC sheets point out that these hybrid structures could be promising for applications in optical spectroscopies, such as SERS. In this work, two model dioxin-like pollutants, TCDD and TCDF, and a model h-BNC surface composed of a carbon nanodisk of ninety-six atoms surrounded by a string of borazine rings, BNC96, are used to simulate the adsorption complexes and the static and pre-resonance Raman spectra of the adsorbed molecules. A high affinity of BNC96 for these pollutants is reflected by the large interaction energies obtained for the most stable stacking complexes, with dispersion being the most important contribution to their stability. The strong vibrational coupling of some active modes of TCDF and, specially, of TCDD causes the static Raman spectra to show a ”pure” chemical enhancement of one order of magnitude. On the other hand, due to the strong electromagnetic response of BNC96, confined within the carbon nanodisk, the pre-resonance Raman spectra obtained for TCDD and TCDF display large enhancement factors of 108 and 107, respectively. Promisingly, laser excitation wavelengths commonly used in SERS experiments also induce significant Raman enhancements of around 104 for the TCDD and TCDF signals. Both the strong confinement of the electromagnetic response within the carbon domains and the high modulation of the resonance wavelengths in the visible and/or UV region in h-BNCs should lead to a higher sensitivity than that of graphene and white graphene parent structures, thus overcoming one of the main disadvantages of using 2D substrates for SERS applications.
      Citation: Chemosensors
      PubDate: 2023-04-29
      DOI: 10.3390/chemosensors11050266
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 267: Printable and Flexible Iridium
           Oxide-Based pH Sensor by a Roll-to-Roll Process

    • Authors: Khengdauliu Chawang, Sen Bing, Jung-Chih Chiao
      First page: 267
      Abstract: A flexible pH sensor based on using iridium oxide (IrOx) as the sensing film was developed by the roll-to-roll (R2R) process. The inert and biocompatible properties of IrOx make it a desired metal oxide for pH-sensing applications. The flexible substrates being continuously processed by the R2R technique provides the advantages of scalability, reconfigurability, resiliency, on-demand manufacturing, and high throughput, without the need for vacuum systems. Potential sweeps by cyclic voltammetry across the IrOx film against commercial and planar Ag/AgCl electrodes validated the reversible electrochemical mechanisms. Multiple IrOx electrodes showed similar output potentials when continuously tested in the pH range of 2–13, indicating good fabrication uniformity. For practical applications, planar IrOx/Ag-AgCl pairs developed on polyimide substrates were tested, with a good linear fit within pH 2–13, achieving Nernstian responses of around −60.6 mV/pH. The pH sensors showed good repeatability when analyzed with hysteresis, drift, fluctuation, and deviation as the stability factors. The selectivity of the interference ions and the effect of temperature were studied and compared with the reported values. The electrodes were further laminated in a process compatible with the R2R technique for packaging. The flexible sensors were tested under flat and curved surface conditions. Tests in artificial sweat and viscous solutions were analyzed in the Clarke error grid, showing reliable pH-sensing performance. The materials used during the manufacturing processes were sustainable, as the active materials were in small amounts and there was no waste during processing. No toxic chemicals were needed in the fabrication processes. The cost-effective and efficient materials and the fabrication process allow for rapid production that is necessary for disposable and point-of-care devices. Flexible electronics provide a platform for device and sensor integration and packaging, which enables Internet-of-things (IoT) network applications.
      Citation: Chemosensors
      PubDate: 2023-04-30
      DOI: 10.3390/chemosensors11050267
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 268: Highly Selective Uricase-Based
           Quantification of Uric Acid Using Hydrogen Peroxide Sensitive
           Poly-(vinylpyrrolidone) Templated Copper Nanoclusters as a Fluorescence

    • Authors: Ramar Rajamanikandan, Malaichamy Ilanchelian, Heongkyu Ju
      First page: 268
      Abstract: We reported on uric acid (UA) detection using a new fluorescence-based assay: poly-(vinylpyrrolidone) templated copper nanoclusters (PVP-CuNCs) with uricase in an aqueous medium, such as human urine with uricase. These nanoclusters were synthesized in a simple wet chemical method and their morphological and optical properties were examined with the aid of high-resolution transmission electron microscopy and optical absorbance/emission spectroscopy. The PVP-CuNCs acted as the fluorescence indicators that used the enzyme-catalyzed oxidation of UA with uricase. Adding UA into the hybrid PVP-CuNCs/uricase solution caused enzyme-catalyzed oxidation to occur, producing hydrogen peroxide (H2O2), allantoin, and carbon dioxide. The fluorescence intensity of PVP-CuNCs is decreased by this biocatalytically generated H2O2, and this decrease is proportional to the UA level. A calibration plot showed the linear relationship with the negative slope between fluorescence intensity and UA in the range of 5–100 × 10−7 mol/L. The limit of detection (LOD) of UA was estimated as 113 × 10−9 mol/L. This fluorescent probe turned out to be highly specific for UA over other biologically relevant molecules. The demonstrated capability of the PVP-CuNCs as the nanoprobes for quantification of the UA levels in human urine samples could potentially pave the way toward medical applications where a super-sensitive, cost-effective, and UA-specific diagnosis was required.
      Citation: Chemosensors
      PubDate: 2023-05-01
      DOI: 10.3390/chemosensors11050268
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 269: Research Progress on Chiral
           Supramolecular Sensors for Enantiomer Detection

    • Authors: Xiao-Fan Wu, Qing-Mei Ge, Nan Jiang, Wen-Feng Zhao, Mao Liu, Hang Cong, Jiang-Lin Zhao
      First page: 269
      Abstract: Chiral substances occur naturally in abiotic and living systems. The recognition and detection of chiral substances in the natural environment or their analysis and detection in biological systems are crucial. Chiral recognition is a research hotspot in clinical medicine, pharmacology, biochemistry, and other fields. Indeed, many researchers have developed various sensors with different functionalized materials for detecting and analyzing enantiomers. Supramolecular systems have important applications in the development of molecular recognition technologies, and the development of supramolecular chemistry is closely related to research on molecular devices. Therefore, this review summarizes the principle of chiral supramolecular sensors for the detection of enantiomers from the perspective of various sensor types, including optical, electrochemical, electrochemical luminescence, photoelectric, and supramolecular chemical sensors. This review also summarizes the relevant reports on chiral supramolecular sensors in the last five years. Finally, we highlight the prospects of supramolecular chiral sensors in future research.
      Citation: Chemosensors
      PubDate: 2023-05-01
      DOI: 10.3390/chemosensors11050269
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 270: Dual-Mode Stretchable Sensor Array with
           Integrated Capacitive and Mechanoluminescent Sensor Unit for Static and
           Dynamic Strain Mapping

    • Authors: Song Wang, Xiaohui Yi, Ye Zhang, Zhiyi Gao, Ziyin Xiang, Yuwei Wang, Yuanzhao Wu, Yiwei Liu, Jie Shang, Run-Wei Li
      First page: 270
      Abstract: Electronic skin (e-skin) has the potential to detect large-scale strain, which is typically achieved by integrating multiple strain sensors into an array. However, the latency and limited resolution of sensing have hindered its large-scale sensing applications. Here, we have developed a high-resolution detection sensing system capable of detecting static and dynamic strain with a simple fabrication process by combining capacitive and mechanoluminescent (ML) sensor units. An elastic polydimethylsiloxane (PDMS) composite film doped with ZnS:Cu and BaTiO3(BT) particles are fabricated as the functional film of the capacitive sensor. In contrast, the transparent electrode was fabricated on the surface of the as-prepared film. By incorporating BT nanoparticles into the elastic substrate, the ML intensity of the ZnS:Cu was improved up to 2.89 times that without BT addition, and the sensitivity of the capacitive sensor was increased as well. The capacitive part of the sensor presented a GF of 0.9 and good stability, while the ML part exhibited excellent performance, making it suitable for both static and dynamic sensing. Furthermore, the strain sensor integrated by 10 × 10 sensing units is demonstrated to detect large-scale strain with high resolution. Moreover, finger joint strain distribution tracking is achieved by attaching the strain sensor unit to the finger joint. With these characteristics, the e-skin may have great potential for bio-motion monitoring and human-computer interaction applications.
      Citation: Chemosensors
      PubDate: 2023-05-02
      DOI: 10.3390/chemosensors11050270
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 271: Accelerated Deactivation of Mesoporous
           Co3O4-Supported Au–Pd Catalyst through Gas Sensor Operation

    • Authors: Xuemeng Lyu, Olena Yurchenko, Patrick Diehle, Frank Altmann, Jürgen Wöllenstein, Katrin Schmitt
      First page: 271
      Abstract: High activity of a catalyst and its thermal stability over a lifetime are essential for catalytic applications, including catalytic gas sensors. Highly porous materials are attractive to support metal catalysts because they can carry a large quantity of well-dispersed metal nanoparticles, which are well-accessible for reactants. The present work investigates the long-term stability of mesoporous Co3O4-supported Au–Pd catalyst (Au–Pd@meso-Co3O4), with a metal loading of 7.5 wt% and catalytically active mesoporous Co3O4 (meso-Co3O4) for use in catalytic gas sensors. Both catalysts were characterized concerning their sensor response towards different concentrations of methane and propane (0.05–1%) at operating temperatures ranging from 200 °C to 400 °C for a duration of 400 h. The initially high sensor response of Au–Pd@meso-Co3O4 to methane and propane decreased significantly after a long-term operation, while the sensor response of meso-Co3O4 without metallic catalyst was less affected. Electron microscopy studies revealed that the hollow mesoporous structure of the Co3O4 support is lost in the presence of Au–Pd particles. Additionally, Ostwald ripening of Au–Pd nanoparticles was observed. The morphology of pure meso-Co3O4 was less altered. The low thermodynamical stability of mesoporous structure and low phase transformation temperature of Co3O4, as well as high metal loading, are parameters influencing the accelerated sintering and deactivation of Au–Pd@meso-Co3O4 catalyst. Despite its high catalytic activity, Au–Pd@meso-Co3O4 is not long-term stable at increased operating temperatures and is thus not well-suited for gas sensors.
      Citation: Chemosensors
      PubDate: 2023-05-02
      DOI: 10.3390/chemosensors11050271
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 272: Handheld Near-Infrared Spectroscopy:
           State-of-the-Art Instrumentation and Applications in Material
           Identification, Food Authentication, and Environmental Investigations

    • Authors: Hui Yan, Marina De Gea Neves, Isao Noda, Gonçalo M. Guedes, António C. Silva Ferreira, Frank Pfeifer, Xinyu Chen, Heinz W. Siesler
      First page: 272
      Abstract: This present review article considers the rapid development of miniaturized handheld near-infrared spectrometers over the last decade and provides an overview of current instrumental developments and exemplary applications in the fields of material and food control as well as environmentally relevant investigations. Care is taken, however, not to fall into the exaggerated and sometimes unrealistic narrative of some direct-to-consumer companies, which has raised unrealistic expectations with full-bodied promises but has harmed the very valuable technology of NIR spectroscopy, rather than promoting its further development. Special attention will also be paid to possible applications that will allow a clientele that is not necessarily scientifically trained to solve quality control and authentication problems with this technology in everyday life.
      Citation: Chemosensors
      PubDate: 2023-05-02
      DOI: 10.3390/chemosensors11050272
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 273: Volatile Compound Profile Analysis of
           Seasonal Flower, Fruit, Leaf, and Stem of Zanthoxylum armatum DC. from
           Manipur Using HS-SPME-GC-MS

    • Authors: Moirangthem Lakshmipriyari Devi, Nameirakpam Bunindro Singh, Kongbrailatpam Chandradev Sharma, Yallappa Rajashekar, Amrita Mishra, Sudripta Das
      First page: 273
      Abstract: In the present study, GC-MS analyses were performed with powder samples of flower, fruit, leaf, and stem of Zanthoxylum armatum DC. collected from Thambalkhong, Imphal-East district of Manipur, a north-eastern region of India, based on the season and growth stage of the plant using the extraction method headspace solid-phase microextraction (HS-SPME) to study the total profile of volatile compounds. Variations were discovered in the volatile compound profiles. HS-SPME-GC-MS analyses of the plant parts detected and identified 16 to 36 compounds and found a total area percentage composition of 96.81 to 98.63%. The analysis showed that nine common compounds were detected in the studied plant parts and seasons, namely, α-thujene, α-pinene, sabinene, β-pinene, terpinolene, o-cymene, sylvestrene, eucalyptol, and caryophyllene. The monoterpenoid eucalyptol (1,8-cineole) was revealed to be the principal component with an area percentage composition of 31.02% in spring leaf to 73.16% in monsoon stem. The extraction method used in this investigation was very fast and feasible for the analysis, and the findings of the present study will help understand the mechanism behind the changes in the plant’s volatile organic compound profile and future research work for selecting aroma-rich accessions for targeted improvement of this plant.
      Citation: Chemosensors
      PubDate: 2023-05-02
      DOI: 10.3390/chemosensors11050273
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 274: Hierarchical Modeling to Enhance
           Spectrophotometry Measurements—Overcoming Dynamic Range Limitations
           for Remote Monitoring of Neptunium

    • Authors: Hunter B. Andrews, Luke R. Sadergaski
      First page: 274
      Abstract: A robust hierarchical model has been demonstrated for monitoring a wide range of neptunium concentrations (0.75–890 mM) and varying temperatures (10–80 ∘C) using chemometrics and feature selection. The visible–near infrared electronic absorption spectrum (400–1700 nm) of monocharged neptunyl dioxocation (Np(V) = NpO2+) includes many bands, which have molar absorption coefficients that differ by nearly 2 orders of magnitude. The shape, position, and intensity of these bands differ with chemical interactions and changing temperature. These challenges make traditional quantification by univariate methods unfeasible. Measuring Np(V) concentration over several orders of magnitude would typically necessitate cells with varying path length, optical switches, and/or multiple spectrophotometers. Alternatively, the differences in the molar extinction coefficients for multiple absorption bands can be used to quantify Np(V) concentration over 3 orders of magnitude with a single optical path length (1 mm) and a hierarchical multivariate model. In this work, principal component analysis was used to distinguish the concentration regime of the sample, directing it to the relevant partial least squares regression submodels. Each submodel was optimized with unique feature selection filters that were selected by a genetic algorithm to enhance predictions. Through this approach, the percent root mean square error of prediction values were ≤1.05% for Np(V) concentrations and ≤4% for temperatures. This approach may be applied to other nuclear fuel cycle and environmental applications requiring real-time spectroscopic measurements over a wide range of conditions.
      Citation: Chemosensors
      PubDate: 2023-05-02
      DOI: 10.3390/chemosensors11050274
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 275: Ziziphus spina-christi Leaf-Derived
           Carbon Dots as a Fluorescence Nanosensor to Evaluate Rifaximin
           Antibacterial via Inner Filter Effect: Greenness and Whiteness Studies

    • Authors: Mohamed A. El Hamd, Marzough Aziz Albalawi, Hassanien Gomaa, Bassam Shaaban Mohammad, Rady F. Abdul-Kareem, Reem H. Obaydo, Wejdan T. Alsaggaf, Safaa F. Saleh, Manal A. Alossaimi, Mohamed A. Abdel-Lateef
      First page: 275
      Abstract: Rifaximin (RFX) is a non-absorbable antibiotic with broad-spectrum efficacy. It treats travelers’ diarrhea, irritable bowel syndrome, non-systematic bacterial diarrhea, bowel infections, overgrowth syndrome, and enteric infections. In this work, carbon dots prepared from Ziziphus spina-christi leaves’ powders are utilized as a green fluorometric biosensor for the assessment of RFX. The morphological lineaments of the prepared carbon dots were recognized by using TEM and SEM techniques. The prepared carbon dots manifest a fluorescence emission peak at 432 nm after an excitation fluorescence peak at 366 nm. The absorbance band of RFX (absorbance peaks at 370 nm and 443 nm) could be thoroughly overlapped with fluorescence excitation/emission bands of the produced carbon dots. A fluorometric tool has been designed and validated for the evaluation of RFX reliant on the inner filter effect methodology, in which the produced carbon dots act as an inner filter effect fluorophore and RFX as an inner filter effect absorber. The quenching degree in the fluorescence activity of the prepared carbon dots depended on the concentration of RFX. The analytical parameters were checked and directed for successfully applied assessment of RFX concentration in different pharmaceutical formulations. The proposed tool’s greenness and eco-friendliness profile was evaluated using the most recent greenness assessment tool, which is the complementary green analytical procedure index (Complex-GAPI) and the Analytical GREEnness metric (AGREE). Additionally, using the recently released White Analytical Chemistry (WAC) tool, the whiteness characteristic—which indicated the method’s sustainability—was investigated.
      Citation: Chemosensors
      PubDate: 2023-05-03
      DOI: 10.3390/chemosensors11050275
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 276: Preparation of Reduced Graphene Oxide
           Sheets with Large Surface Area and Porous Structure for High-Sensitivity
           Humidity Sensor

    • Authors: Seo Jin Kim, Hong Jun Park, Eun Seop Yoon, Bong Gill Choi
      First page: 276
      Abstract: Humidity sensors provide environmental conditions suitable for several applications. However, they suffer from a limited reliable range originating from the low electrical conductivity and low water-sensitive sites of humidity-sensing materials. In this study, we developed high-sensitivity humidity sensors based on holey-reduced graphene oxide (HRGO) with a large surface area (274.5 m2/g) and an abundant pore structure. HRGO was prepared via the H2O2-etching-reaction-assisted hydrothermal processing of graphene oxide sheets. The resulting humidity sensor exhibited high sensitivity (−0.04317 log Z/%RH, R2 = 0.9717), a fast response time (<3 s), and long-term stability over 28 days. The impedance responses of the humidity sensor were almost similar between the mechanically standard and bent states. Furthermore, electrochemical impedance spectroscopy was performed to understand the humidity-sensing mechanism of the HRGO materials.
      Citation: Chemosensors
      PubDate: 2023-05-04
      DOI: 10.3390/chemosensors11050276
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 277: A Novel Rare Earth and Covalent Organic
           Framework Composite for Rapid and Highly Sensitive Electrochemical
           Analysis of Sulfadiazine in Fish Muscle

    • Authors: Jiajia Han, Zicong Liao, Guosheng Chen, Junlang Qiu, Fang Zhu
      First page: 277
      Abstract: The misuse of sulfadiazine (SFZ) has led to great hazard to the environment and human safety; therefore, a simple, rapid, and sensitive method to detect sulfadiazine is urgently needed. Herein, we report a simple fabrication method for rare earth vanadate samarium (SmV)-doped covalent organic framework COFTDBA-TTL nanocomposites (SmV/COFTDBA-TTL), which were used to construct a sulfadiazine (SFZ) electrochemical sensor. The synergistic effect arising from the combination of SmV and COFTDBA-TTL accelerates the charge transfer kinetics, along with the creation of more surface-active sites that benefit effective detection. Compared with other electrochemical sensors, this electrochemical sensor exhibits low detection limit (2.40 nM), wide linear range (7.32–12.0 μM), good reproducibility (RSD = 0.823%), and stability (RSD = 3.60%). It provides a novel method and theoretical basis for the application of rare earth COF-based electrochemical sensors to detect environmentally destructive pollutants.
      Citation: Chemosensors
      PubDate: 2023-05-05
      DOI: 10.3390/chemosensors11050277
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 278: Development of ANN Models for Prediction
           of Physical and Chemical Characteristics of Oil-in-Aqueous Plant Extract
           Emulsions Using Near-Infrared Spectroscopy

    • Authors: Sara Sirovec, Maja Benković, Davor Valinger, Tea Sokač Cvetnić, Jasenka Gajdoš Kljusurić, Ana Jurinjak Tušek, Tamara Jurina
      First page: 278
      Abstract: The potential of applying Artificial Neural Network (ANN) models based on near-infrared (NIR) spectra for the characterization of physical and chemical features of oil-in-aqueous oregano/rosemary extract emulsions was explored in this work. Emulsions were prepared using a batch emulsification process, with pea protein as the emulsifier. NIR spectral data were connected to the results of the analysis of physical and chemical properties of the emulsions (zeta potential, Feret droplet diameter, total polyphenolic content, and antioxidant capacity) with the final aim of quantitative prediction of the physical and chemical features. For that purpose, robust non-linear multivariate analysis (Artificial Neural Network modeling) was applied. The spectra themselves were preprocessed using several approaches (raw spectra, Savitzky–Golay smoothing, standard normal variate, and multiplicative scatter corrections) after which the impact of NIR spectral preprocessing on the ANN model’s efficiency was evaluated. The results show that NIR spectroscopy integrated with ANN computation can be employed to quantitatively predict the physical and chemical properties of oil-in-plant extract emulsions (R2 > 0.9).
      Citation: Chemosensors
      PubDate: 2023-05-05
      DOI: 10.3390/chemosensors11050278
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 279: Fluorescence Evolution of Gold
           Nanoclusters in the Presence of Shapely Silver Nanoparticles and UV-Vis

    • Authors: Jui-Chang Chen, Wen-Chuan Hsiao, Chen-Yu Hsu, Bo-Hao Huang, Cheng-Liang Huang
      First page: 279
      Abstract: Gold nanoclusters (Au NCs) belong to a class of materials that is highly fluorescent and biocompatible. Bovine serum albumin (BSA) protected gold nanoclusters (BSA-Au NCs) have been extensively used in biological applications due to their easy synthesis and relatively high quantum yield. Therefore, understanding the behavior of BSA-Au NCs in different chemical and physical environments is essential to enhance their application in biological systems. In this study, we investigated the effect of plasmonic nanostructures with different localized surface plasmon resonance (LSPR) wavelengths on the behavior of BSA-Au NCs by recording time-dependent fluorescence spectra in the presence of silver nanoparticles (AgNPs) with various shapes. However, we did not observe any conclusive LSPR-wavelength-dependent fluorescent behavior. Additionally, the fluorescence intensity of BSA-Au NCs exhibited gradual decay under light excitation, even at several hundred μW/cm2 in a fluorescence spectrometer, indicating that they are not as photostable as previously assumed. We found further that the photostability of BSA-Au NCs is affected by the wavelength of the incident light (370, 420, 480, and 550 nm), which can be accurately described using bi-exponential decay functions. Our study provides an easy in situ method to evaluate the photostability of Au NCs under different-wavelength light irradiation using a commercial fluorescence spectrometer.
      Citation: Chemosensors
      PubDate: 2023-05-06
      DOI: 10.3390/chemosensors11050279
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 280: Fluorescent Probes for Biomacromolecules
           Based on Monomethine Cyanine Dyes

    • Authors: Pavel G. Pronkin, Alexander S. Tatikolov
      First page: 280
      Abstract: Monomethine cyanine dyes (MCDs) are widely applied as biomolecular probes and stains in biochemical and biomedical research. This is based on the ability of MCDs to associate with biomolecules (mostly nucleic acids) with significant fluorescent growth. The present review considers the works devoted to the properties of MCDs and the influence of noncovalent interactions with biomacromolecules on their properties, as well as their use as noncovalent probes and stains for various biomacromolecules. The synthesis and photonics (photophysics and photochemistry; in particular, the generation of the triplet state) of MCDs are also considered. Areas and prospects of the practical applications of MCDs in biochemistry and biomedicine are discussed.
      Citation: Chemosensors
      PubDate: 2023-05-07
      DOI: 10.3390/chemosensors11050280
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 281: Recent Advances in
           Electrochemiluminescence-Based Single-Cell Analysis

    • Authors: Qian-Nan He, Zheng-Yuan Ma, Yu-Xin Yang, Cong-Hui Xu, Wei Zhao
      First page: 281
      Abstract: In recent years, the increasing demand for highly sensitive tracking of life processes has promoted scientists to explore advanced analytical techniques. Developing universal analytical methods to detect individual differences and temporal changes among cells is crucial for fundamental study and clinical applications. Among existing technologies, the electrochemiluminescence (ECL) approach has attracted attention for various purposes, such as detecting biomolecules, monitoring cellular activities, imaging subcellular structures, and evaluating cell viability. ECL analysis and imaging provide high sensitivity, low background noise, and spatiotemporal resolution for single-cell analysis. In this review, we explore the evolution of ECL technology in cell analysis and emphasize single-cell assays, including detecting released cellular molecules and surface biomarkers, analysing intracellular components, imaging cell membranes, and cell adhesion. We first briefly introduce the mechanism and apparatus for ECL-based single-cell analysis and, subsequently, focus on four aspects of research related to single-cell analysis and imaging. Furthermore, the latest advances in ECL-driven photodynamic therapy and super-resolution ECL microscopy are also discussed. Finally, we discuss the current obstacles and prospects for ECL single-cell analysis.
      Citation: Chemosensors
      PubDate: 2023-05-07
      DOI: 10.3390/chemosensors11050281
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 282: Chemists Focus on Probes, Biologists on
           Cells—But Who Talks about Probe-Cell Interactions' A Critical
           Account of the Suboptimal Reporting of Novel Fluorescent Imaging Probes,
           Using Lipid Droplet Stains as a Case Study

    • Authors: Richard W. Horobin
      First page: 282
      Abstract: Many current reports in the scientific literature describe novel fluorescent probes intended to provide information on various structures or properties of live cells by using microscopic imaging. Unfortunately, many such reports fail to provide key information regarding the staining process. It is often the case that neither the necessary minimum technical detail (probe concentration, solvent and cosolute, temperature and time of staining, and details of post-staining washes) nor a discussion of the proposed staining mechanism are provided. Such omissions make it unnecessarily difficult for biomedical end-users to try out reported novel probes in their own laboratories. The validity of these criticisms is explored and demonstrated by a detailed analysis of 75 non-cherry-picked articles describing novel fluorescent probes for the detection of lipid droplets in live cells. This dataset also suggests that papers from journals with high journal impact factors or from better-known research groups are no more likely to provide better protocol information or discussion of the mechanism than papers from less prestigious sources. Comments on possible reasons for this suboptimal reporting are offered. The use of a suitable information/feature checklist, following best practice in many leading chemical and biological journals, is suggested as a mechanism for ameliorating this situation, with a draft checklist being provided.
      Citation: Chemosensors
      PubDate: 2023-05-08
      DOI: 10.3390/chemosensors11050282
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 283: 3D-Printed Hydrodynamic Focusing
           Lab-on-a-Chip Device for Impedance Flow Particle Analysis

    • Authors: Dayananda Desagani, Shani Kleiman, Teddy Zagardan, Hadar Ben-Yoav
      First page: 283
      Abstract: Particles analysis, such as cell counting and differentiation, are widely used for the diagnosis and monitoring of several medical conditions, such as during inflammation. Three-dimensional-printed lab-on-a-chip (LOC) devices, which can utilize one of the cell counting methods, can bring this technology to remote locations through its cost-efficient advantages and easy handling. We present a three-dimensional-printed LOC device with integrated electrodes. To overcome the limited resolution of a 3D printer, we utilized a flow-focusing design. We modeled and simulated the mass transfer and flow dynamics in the LOC by incorporating a flow-focusing design and reached an optimal channel diameter of 0.5 mm, resulting in a flow-focusing distance of <60 µm. We also used electrochemical impedance spectroscopy to enable the dependence of the electrode–solution interface on the flow-focusing properties. Finally, we highlighted the proof-of-concept detection of microspheres (6 µm diameter), which model biological cells that flow in the channel, by recording the electrochemical impedance at 10 kHz, thus showing the potential of a future point-of-care (POC) device.
      Citation: Chemosensors
      PubDate: 2023-05-08
      DOI: 10.3390/chemosensors11050283
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 284: Detection of Water Vapor by

    • Authors: Toshihiro Shimada, Honami Nishimoto, Hikaru Hayakawa, Hisashi Ichikawa, Yoshifumi Nakacho
      First page: 284
      Abstract: We examined the possibility of detecting water vapor by chemiluminescence using the reaction of popular “chemical light” (bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl)oxalate with H2O2). H2O2 is released from sodium percarbonate exposed to water molecules as in the oxygen bleach. The release of H2O2 by water vapor was confirmed by mass spectrometry in a vacuum. The chemiluminescence from the mixed reagents was observed when exposed to water vapor. This method opens the way to locally detect the faulty points of water barrier films and observe the real-time failure of the barrier films during bending tests of flexible packing materials. A molecular dynamics simulation was performed to study the diffusion of H2O2 molecules in polymers.
      Citation: Chemosensors
      PubDate: 2023-05-09
      DOI: 10.3390/chemosensors11050284
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 285: Effects of Oxygen Partial Pressure and
           Thermal Annealing on the Electrical Properties and High-Temperature
           Stability of Pt Thin-Film Resistors

    • Authors: Yawen Pang, Nan Zhao, Yong Ruan, Limin Sun, Congchun Zhang
      First page: 285
      Abstract: The effects of oxygen partial pressure and annealing temperature on the microstructure, electrical properties, and film adhesion of Pt thin-film resistors with PtxOy as the adhesion layer were investigated. Pt/PtxOy films were deposited on alumina substrates by radio frequency sputtering and annealed in a muffle furnace at temperatures in the range of 800–1000 °C. The microstructure and chemical composition of Pt thin-film resistors were examined by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The experimental results show that annealing will lead to the formation of bubbles on the surface of the film, and the film prepared at 20% oxygen partial pressure has the least bubbles. The Pt thin-film resistors with a PtxOy adhesion layer sputtered with 10% oxygen partial pressure had the highest TCR (temperature coefficient of resistance) of 3434 ppm/°C, and the TCR increased with increasing annealing temperature. Repeated experiments show that Pt thin-film resistors have better stability at annealing temperatures of 800 °C and 900 °C. Comprehensively considering the TCR and stability, the optimal adhesion layer of Pt thin-film resistors was prepared at an oxygen partial pressure of 10% and an annealing temperature of 900 °C.
      Citation: Chemosensors
      PubDate: 2023-05-10
      DOI: 10.3390/chemosensors11050285
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 286: A Highly Sensitive and Selective
           Near-Infrared Fluorescent Probe for Detecting Peroxynitrite in Living
           Cells and Drosophila Brains

    • Authors: Wei Wang, Jian-Bin Deng, Long Jin, Bai-Ou Guan
      First page: 286
      Abstract: Peroxynitrite (ONOO−) is a highly reactive nitrogen species (RNS) that is closely associated with many physiological and pathological processes. In this study, we construct a near-infrared (NIR) fluorescent probe, NAF-BN, that utilizes benzyl boronic acid ester for fluorescence quenching of naphthofluorescein cores. NAF-BN has been thoroughly evaluated for reliable imaging of exogenous ONOO− in living cells. Further, NAF-BN can be applied effectively to visualize ONOO− in Drosophila brains, confirming the hypothesis that neonicotinoid pesticides increase neurological damage and oxidative stress. The probe NAF-BN offers exciting potential to reveal the role of ONOO− in various biological and medical fields.
      Citation: Chemosensors
      PubDate: 2023-05-11
      DOI: 10.3390/chemosensors11050286
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 287: Application of an Electronic Nose
           Technology for the Prediction of Chemical Process Contaminants in Roasted

    • Authors: Marta Mesías, Juan Diego Barea-Ramos, Jesús Lozano, Francisco J. Morales, Daniel Martín-Vertedor
      First page: 287
      Abstract: The purpose of this study was to investigate the use of an experimental electronic nose (E-nose) as a predictive tool for detecting the formation of chemical process contaminants in roasted almonds. Whole and ground almonds were subjected to different thermal treatments, and the levels of acrylamide, hydroxymethylfurfural (HMF) and furfural were analysed. Subsequently, the aromas were detected by using the electronic device. Roasted almonds were classified as positive or negative sensory attributes by a tasting panel. Positive aromas were related to the intensity of the almond odour and the roasted aroma, whereas negative ones were linked to a burnt smell resulting from high-intensity thermal treatments. The electronic signals obtained by the E-nose were correlated with the content of acrylamide, HMF, and furfural (RCV2 > 0.83; RP2 > 0.76 in whole roasted almonds; RCV2  > 0.88; RP 2 > 0.95 in ground roasted almonds). This suggest that the E-nose can predict the presence of these contaminants in roasted almonds. In conclusion, the E-nose may be a useful device to evaluate the quality of roasted foods based on their sensory characteristics but also their safety in terms of the content of harmful compounds, making it a useful predictive chemometric tool for assessing the formation of contaminants during almond processing.
      Citation: Chemosensors
      PubDate: 2023-05-11
      DOI: 10.3390/chemosensors11050287
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 288: Preparation of 2-Butanone Gas Sensor
           Based on Ag-Decorated In2O3 Nanocube with High Response and Low Detection

    • Authors: Hua Zhang, Yinghao Guo, Hongliang Gao, Fanli Meng
      First page: 288
      Abstract: In this work, 2-butanone-sensitive Ag-decorated In2O3 nanocomposites were successfully prepared using a facile one-step hydrothermal method to enhance the sensing performance of In2O3 nanocubes. The methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) analysis, and X-ray photoelectron spectroscopy (XPS) were used to observe the morphology, microstructure, crystalline phase, and the existing state of the elements in the produced nanomaterials, respectively. The gas sensing test results show that the prepared compounds could respond to 100 ppm of 2-butanone with a high response (242), fourfold that of the pure In2O3 material, at the optimum working temperature of 240 °C. Moreover, the Ag@In2O3-based sensor also showed excellent selectivity, good repeatability, and even long-term stability. In addition, noble metal surface modification not only decreased the optimum operating temperature (from 270 °C to 240 °C) but also decreased the lowest detection limit (from 5 ppm to 0.25 ppm). In the final section, the gas sensing mechanism of the Ag@In2O3-based sensor and the probable reason for 2-butanone’s enhanced sensing properties are both discussed.
      Citation: Chemosensors
      PubDate: 2023-05-11
      DOI: 10.3390/chemosensors11050288
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 289: Ppb-Level NO2 Sensor with High
           Selectivity Fabricated by Flower-like Au-Loaded In2O3

    • Authors: Ji Zhang, Fangfang Zhang, Xu Li, Qingji Wang
      First page: 289
      Abstract: With increasingly serious environmental problems caused by the improvement in people’s living standards, the number of cars has increased sharply in recent years, which directly leads to the continuous increase in the concentration of NO2 in the air. NO2 is a common toxic and irritant gas, which is harmful to both the human body and the environment. Therefore, this research focuses on NO2 detection and is committed to developing high-performance, low detection limit NO2 sensors. In this study, flower-like Au-loaded In2O3 was successfully fabricated using the hydrothermal method and the wet impregnation method. The morphological features and chemical compositions of the as-prepared samples were characterized using SEM, TEM, XRD and XPS. A variety of sensors were fabricated and the gas-sensing properties of sensors were investigated. The results indicate that the sensor based on 0.5 mol% Au/In2O3 shows a response value of 1624 to 1 ppm NO2 at 100 °C, which is 14 times that based on pure In2O3. Meanwhile, the detection limit of the sensor based on 0.5 mol% Au/In2O3 for NO2 is 10 ppb, and the response value is 10.4. In addition, the sensor based on 0.5 mol% Au/In2O3 also has high selectivity to NO2 among CO, CO2, H2, CH4, NH3, SO2 and H2S. Finally, the sensitization mechanism of Au/In2O3 was discussed, and the reasons for improving the performance of the sensor were analyzed. The above results and analysis demonstrate that the gas-sensing attributes of the sensor based on 0.5 mol% Au/In2O3 to NO2 improved remarkably; at the same time, it has been proved that the composite material has extensive potential in practical applications.
      Citation: Chemosensors
      PubDate: 2023-05-12
      DOI: 10.3390/chemosensors11050289
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 290: Enzymeless Electrochemical Glucose
           Sensors Based on Metal–Organic Framework Materials: Current
           Developments and Progresses

    • Authors: Chang Liu, Jian Zhou, Rongqiu Yan, Lina Wei, Chenghong Lei
      First page: 290
      Abstract: Electrochemical glucose sensors play a crucial role in medicine, bioscience, food science, and agricultural science. Metal–organic frameworks possess exceptional properties, such as large specific surface area, high porosity, tunable pore structure, high catalytic activity, open metal active sites, and structural diversity. The catalytic activity of metal–organic frameworks enables electrocatalytic oxidation of glucose without the need for enzymes. Consequently, enzymeless electrochemical glucose sensors based on metal–organic framework materials have gained much attention and have been extensively studied for glucose detection. This mini-review provides an overview of the development and progress of enzymeless electrochemical glucose detection based on metal–organic framework material–modified electrodes, including doping materials, sensitivity, detection limit, and fast response capability. With the advancement of this technology, enzymeless electrochemical glucose sensors can continuously and stably detect glucose and can be utilized in various fields, such as wearable devices.
      Citation: Chemosensors
      PubDate: 2023-05-12
      DOI: 10.3390/chemosensors11050290
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 291: Flexible Humidity Sensor Based on Au
           Nanoparticles/Organosilica-Containing Polyelectrolyte Composite

    • Authors: Pi-Guey Su, Chih-Chang Hsu
      First page: 291
      Abstract: A novel flexible humidity sensor incorporating gold nanoparticles (Au NPs) and a trifunctional organosilica compound has been developed through the integration of sol–gel processing, free radical polymerization, and self-assembly techniques. The trifunctional organosilica was initially synthesized by modifying (3-mercaptopropyl)trimethoxysilane (thiol-MPTMS) with 3-(trimethoxysilyl)propyl methacrylate (vinyl-TMSPMA). Subsequently, a hydrophilic polyelectrolyte, [3(methacryloylamino)propyl]trimethyl ammonium chloride (MAPTAC), was grafted onto the MPTMS-TMSPMA gel. The Au NPs were assembled onto the thiol groups present in the MPTMS-TMSPMA-MAPTAC gel network. The compositional and microstructural properties of the Au NPs/MPTMS-TMSPMA-MAPTAC composite film were investigated utilizing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The presence of thiol groups and mesoporous silica skeletons ensured the stability of the humidity-sensing film on the substrate under highly humid conditions, while the hydrophilic groups functioned as humidity-sensitive sites. This innovative humidity sensor demonstrated high sensitivity, acceptable linearity, minimal hysteresis, and rapid response time across a broad range of working humidity levels. Based on the complex impedance spectra analysis, hydronium ions (H3O+) were determined to govern the conductance process of the flexible humidity sensor.
      Citation: Chemosensors
      PubDate: 2023-05-13
      DOI: 10.3390/chemosensors11050291
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 292: Screening the Specific Surface Area for
           Metal-Organic Frameworks by Cataluminescence

    • Authors: Zenghe Li, Danning Pei, Rui Tian, Chao Lu
      First page: 292
      Abstract: Metal-organic frameworks (MOFs) are famous for their large surface area, which is responsible for the dispersed active sites and decent behaviors in gas adsorption, storage, and catalytic reactions. However, it remains a great challenge to acquire a cost-effective and accurate evaluation on the surface area for the MOFs. In this work, we have proposed cataluminescence (CTL) to evaluate the specific surface area for the MOFs, based on the adsorption–desorption and the catalytic reaction of ethanol. Aluminum-based MOFs with large-pore (lp), narrow-pore (np), and medium-pore (mp-130, mp-140, and mp-150 synthesized under 130, 140, and 150 °C) have been prepared. Distinguished CTL signals were acquired from ethanol in the presence of these MOFs: lp > mp-150 > mp-130 > mp-140 > np. Note that the CTL intensities were positively correlated with the specific surface areas of these MOFs acquired by the Brunauer–Emmett–Teller (BET) method. The distinct specific surface area of MOFs determined the capacity to accommodate and activate ethanol, leading to the varied CTL intensity signals. Therefore, the proposed CTL could be utilized for the rapid and accurate evaluation of the specific surface area for MOFs. It is believed that this CTL strategy showed great possibilities in the structural evaluation for various porous materials.
      Citation: Chemosensors
      PubDate: 2023-05-14
      DOI: 10.3390/chemosensors11050292
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 293: Architectures and Mechanisms of Perylene
           Diimide-Based Optical Chemosensors for pH Probing

    • Authors: Shuai Chen, Meng Zhou, Ling Zhu, Xiaomei Yang, Ling Zang
      First page: 293
      Abstract: The precise control and monitoring of pH values remain critical for many chemical, physiological and biological processes. Perylene diimide (PDI)-based molecules and materials exhibit excellent thermal, chemical and photochemical stability, unique UV-vis absorption and fluorescent emission properties, low cytotoxicity, as well as intrinsic electron-withdrawing (n-type semiconductor) nature and impressive molecular assembly capability. These features combined enable promising applications of PDIs in chemosensors via optical signal modulations (e.g., fluorescent or colorimetric). One of the typical applications lies in the probing of pH under various conditions, which in turn helps monitor the extracellular (environmental) and intracellular pH change and pH-relying molecular recognition of inorganic or organic ions, as well as biological species, and so on. In this review, we give a special overview of the recent progress in PDI-based optical chemosensors for pH probing in various aqueous and binary water–organic media. Specific emphasis will be given to the key design roles of sensing materials regarding the architectures and the corresponding sensing mechanisms for a sensitive and selective pH response. The molecular design of PDIs and structural optimization of their assemblies in order to be suitable for sensing various pH ranges as applied in diverse scenarios will be discussed in detail. Moreover, the future perspective will be discussed, focusing on the current key challenges of PDI-based chemosensors in pH monitoring and the potential approach of new research, which may help address the challenges.
      Citation: Chemosensors
      PubDate: 2023-05-14
      DOI: 10.3390/chemosensors11050293
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 294: Identification of Degradation Products
           of the New Anticancer Drug Substance ONC201 by Liquid
           Chromatography–High-Resolution Multistage Mass Spectrometry

    • Authors: Maxime Annereau, Marina Vignes, Tahar Sif Eddine Bouchema, Lucas Denis, Audrey Solgadi, Victoire Vieillard, Muriel Paul, André Rieutord, Jacques Grill, Philippe-Henri Secretan, Bernard Do
      First page: 294
      Abstract: ONC201 (dordaviprone) is a new drug substance used in a compassionate manner to treat patients with glioblastoma. Given the clinical context and the particularly promising preclinical results, we have been asked by the medical authorities to make a first treatment available throughout France as a hospital preparation to allow access to treatment and to conduct clinical trials. However, to control the quality and safety conditions inherent in this academic manufacturing process, while there is virtually no data available to date to understand the stability of ONC201, we had to determine the stability profile of ONC201, i.e., its sensitivity to different stressors and the types of impurities that could form during its degradation. We found that ONC201 was sensitive to oxidation in the presence of hydrogen peroxide or under light irradiation. Both conditions resulted in the formation of 20 degradation products detected and identified by liquid chromatography–high-resolution mass spectrometry. Their structural elucidation required an in-depth study of the fragmentation pattern of protonated ONC201, described for the first time. The product ions of the degradation products were compared to those of ONC201 protonated ion to assign the most plausible structures for all the detected degradation products. Of these degradation products, those that were rapidly produced, of high intensity and/or identified as potentially having a different toxicity profile to ONC201 by in silico studies, were selected to be monitored during batch release testing and stability studies.
      Citation: Chemosensors
      PubDate: 2023-05-15
      DOI: 10.3390/chemosensors11050294
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 295: From 1D to 2D to 3D: Electrospun
           Microstructures towards Wearable Sensing

    • Authors: Jia-Han Zhang, Xidi Sun, Haitao Wang, Jiean Li, Xin Guo, Sheng Li, Yaqun Wang, Wen Cheng, Hao Qiu, Yi Shi, Lijia Pan
      First page: 295
      Abstract: Wearable sensors open unprecedented opportunities for long-term health monitoring and human–machine interaction. Electrospinning is considered to be an ideal technology to produce functional structures for wearable sensors because of its unique merits to endow devices with highly designable functional microstructures, outstanding breathability, biocompatibility, and comfort, as well as its low cost, simple process flow, and high productivity. Recent advances in wearable sensors with one-, two-, or three-dimensional (1D, 2D, or 3D) electrospun microstructures have promoted various applications in healthcare, action monitoring, and physiological information recognition. Particularly, the development of various novel electrospun microstructures different from conventional micro/nanofibrous structures further enhances the electrical, mechanical, thermal, and optical performances of wearable sensors and provides them with multiple detection functions and superior practicality. In this review, we discuss (i) the principle and typical apparatus of electrospinning, (ii) 1D, 2D, and 3D electrospun microstructures for wearable sensing and their construction strategies and physical properties, (iii) applications of microstructured electrospun wearable devices in sensing pressure, temperature, humidity, gas, biochemical molecules, and light, and (iv) challenges of future electrospun wearable sensors for physiological signal recognition, behavior monitoring, personal protection, and health diagnosis.
      Citation: Chemosensors
      PubDate: 2023-05-16
      DOI: 10.3390/chemosensors11050295
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 296: Engineering Band Structure of SnO2
           Nanoparticles via Coupling with g-C3N4 Nanosheet for the Detection of

    • Authors: Jiuyu Li, Kerui Xie, Yating Wang, Ruihua Zhao, Yangyang Shang, Jianping Du
      First page: 296
      Abstract: Volatile organoamines are important industrial raw materials and chemicals. Long-term exposure to amines could be harmful to human health and even cause serious pollution. In this study, SnO2 decorated g-C3N4 material was fabricated and used as a sensor material for the detection of ethanolamine (EA). The structures, morphology, surface chemical states, and band structure were characterized, and gas sensing was studied. The results showed that SnO2 nanoparticles were dispersed on g-C3N4, and band structure was dependent on g-C3N4 doping. Notably, the interface heterojunction was conducive to electron transferring and O2 molecule adsorption; the formed reactive oxygen species enhanced the reaction between oxygen and EA, thus leading to high sensitivity to EA. This composite exhibited a high response that was 2.6 times higher than that of pure SnO2, and the detection limit reached 294 ppb. A g-C3N4/SnO2-based sensor displayed a high selectivity to EA with a fast response time (1 s) and recovery time (20 s) at low operating temperatures. In particular, this sensor exhibited a linear relationship between the response and concentration, which is required for quantitative analysis.
      Citation: Chemosensors
      PubDate: 2023-05-16
      DOI: 10.3390/chemosensors11050296
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 297: Direct Electrochemical Analysis in
           Seawater: Evaluation of Chloride and Bromide Detection

    • Authors: Yuqi Chen, Richard Compton
      First page: 297
      Abstract: Chloride and bromide are two of the most abundant anions found in seawater, and knowledge of their concentrations is essential for environmental monitoring. However, the analysis of chloride and bromide in seawater is challenging due to the complex nature of the seawater matrix. From an electrochemical perspective, we investigate the suitability of three types of electrode (Au, glassy carbon and Pt) for the analysis of Cl− and/or Br− in seawater. With the understanding of their electrochemical behaviours in artificial seawater (ASW), optimal voltammetric procedures for their detection are developed. The results show that the Au electrode is unsuitable for use as a Cl− and/or Br− sensor due to its dissolution and passivation in ASW. The use of glassy carbon resulted in poorly defined chloride and bromide signals. Finally, platinum was found to be a good candidate for chloride detection in artificial seawater using square wave voltammetry, and the results obtained in natural seawater via electrochemical measurement were in good agreement with those obtained via ion chromatography. Platinum electrodes are also recommended for bromide analysis.
      Citation: Chemosensors
      PubDate: 2023-05-18
      DOI: 10.3390/chemosensors11050297
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 298: Methods and Analysis of Biological
           Contaminants in the Biomanufacturing Industry

    • Authors: Mohammad Janghorban, Sara Kazemi, Rigel Tormon, Philippa Ngaju, Richa Pandey
      First page: 298
      Abstract: The advent of bioprocessing has revolutionized the biomanufacturing industry, leading to the rise of biotherapeutics derived from biologic products such as chimeric antigen receptor (CAR) T-cells used for targeted cancer treatment and the Vero cell line for the production of viral vectors and vaccines. Despite these promising developments, most biologic products are characterized by fragile macromolecular structures that are heterogenous with a purity profile that varies with each batch making them susceptible to microorganism contamination. Regulatory oversight of biologic products is imperative to ensure adherence to good manufacturing practices and compliance with quality management systems. Current quality assurance protocols during production include monoclonality during cell line development, real-time monitoring of process parameters, flow cytometry for microbial monitoring, polymerase chain reaction, and immunoassay techniques to amplify DNA sequences related to bacterial or biological contaminants. FDA guidance recommends the implementation of process analytical technology within biomanufacturing production to measure critical quality parameters, which includes screening for potential biological contamination. Future advancements in bioprocess monitoring and control should capitalize on providing cheap, real-time, and sensitive detection. Biosensors, mass spectrometry, and polymerase chain reaction present robust, rapid, and real-time capabilities for multiplexed detection of contaminant analytes and have shown promise in meeting these needs. This review discusses the main biological contaminants of bioprocesses, European Union and FDA regulatory guidelines for monitoring and control within biologics production, existing methods and their limitations, and future advancements for biological contamination detection.
      Citation: Chemosensors
      PubDate: 2023-05-18
      DOI: 10.3390/chemosensors11050298
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 299: Conductive Molecularly Imprinted
           Polymers (cMIPs): Rising and Versatile Key Elements in Chemical Sensing

    • Authors: Adriana Feldner, Julia Völkle, Peter Lieberzeit, Philipp Fruhmann
      First page: 299
      Abstract: Molecularly imprinted polymers (MIPs) have proven useful as receptor materials in chemical sensing and have been reported for a wide range of applications. Based on their simplicity and stability compared to other receptor types, they bear huge application potential related to ongoing digitalization. This is the case especially for conductive molecularly imprinted polymers (cMIPs), which allow easy connection to commercially available sensing platforms; thus, they do not require complex measuring setups. This review provides an overview of the different synthetic approaches toward cMIPs and the obtained limit of detections (LODs) with different transducing systems. In addition, it presents and discusses their use in different application areas to provide a detailed overview of the challenges and possibilities related to cMIP-based sensing systems.
      Citation: Chemosensors
      PubDate: 2023-05-18
      DOI: 10.3390/chemosensors11050299
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 300: Recent Advances for Imidacloprid
           Detection Based on Functional Nanomaterials

    • Authors: Shu Chen, Yawen Wang, Xiuli Liu, Longhua Ding
      First page: 300
      Abstract: Imidacloprid (IMI) has been applied in agricultural production to prevent pests. It is vital to detect IMI residues with high sensitivity for food safety. In general, nanomaterials have driven the development of highly sensitive sensing platforms owing to their unique physical and chemical properties. Nanomaterials play important roles in the construction of high-performance sensors, mainly through sample pretreatment and purification, recognition molecules immobilization, signal amplification, and providing catalytic active sites. This review addresses the advances in IMI sensors based on the combination of nanomaterials and various analytical techniques. The design principles and performance of different chromatographic, electrochemical, and fabricated optical sensors coupled with nanomaterials are discussed. Finally, the challenges and prospects of sensors based on nanomaterials for IMI analysis have also been incorporated.
      Citation: Chemosensors
      PubDate: 2023-05-18
      DOI: 10.3390/chemosensors11050300
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 301: LIBS-MLIF Method: Stromatolite
           Phosphorite Determination

    • Authors: Hongpeng Wang, Yingjian Xin, Peipei Fang, Jianjun Jia, Liang Zhang, Sicong Liu, Xiong Wan
      First page: 301
      Abstract: The search for biominerals is one of the core targets in the deep space exploration mission. Stromatolite phosphorite is a typical biomineral that preserves early life on Earth. The enrichment of phosphate is closely related to microorganisms and their secretions. Laser-induced breakdown spectroscopy (LIBS) has become an essential payload in deep space exploration with the ability to analyze chemical elements remotely, rapidly, and in situ. This paper aims to evaluate the rapid identification of biological and non-biological minerals through a remote LIBS payload. LIBS is used for element analysis and mineral classification determination, and molecular laser-induced fluorescence (MLIF) is used to detect halogenated element F to support the existence of fluorapatite. This paper analyzes the LIBS-MLIF spectral characteristics of stromatolites and preliminarily evaluates the feasibility of P element quantification. The results show that LIBS technology can recognize biological and non-biological signals. This discovery is significant because it is not limited to detecting and analyzing element composition. It can also realize the detection of molecular spectrum based on selective extraction of CaF molecule. Therefore, the LIBS payload still has the potential to search for biomineral under the condition of adjusting the detection strategy.
      Citation: Chemosensors
      PubDate: 2023-05-19
      DOI: 10.3390/chemosensors11050301
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 302: Highly Selective Arsenite Sensor Based
           on Gold Nanoparticles and Ionic Liquids

    • Authors: Xuan Hao Lin, Mann Joe Wong, Sam Fong Yau Li
      First page: 302
      Abstract: Here, we report a highly selective arsenite (As(III)) sensor based on gold nanoparticles (AuNPs) and ionic liquids (ILs). AuNPs were citrate-capped with negative charges on their surfaces, and could aggregate and precipitate once electrolytes were introduced to neutralize the negative charges. In this study, we discovered that organic ILs, behaving similarly to inorganic electrolytes such as NaCl, could induce the aggregation and precipitation of AuNPs much more efficiently than inorganic electrolytes. Since As(III) inhibited while ILs promoted the aggregation of AuNPs, we examined the interactions between AuNPs, As(III), and ILs and the possibility of using ILs and AuNPs as a sensing probe to detect arsenite and determine its concentration. Six different ILs were evaluated for this purpose in this study. Repeatability, interference, stability, selectivity, and sensitivity were investigated to evaluate the As(III) sensing probe. The limit of detection (LOD) of the sensor sBMP was as low as 0.18 ppb, ranked as the second lowest among the reported arsenite sensors. The sensing of arsenite was also demonstrated with real water samples and was cross-validated with ICP-OES.
      Citation: Chemosensors
      PubDate: 2023-05-19
      DOI: 10.3390/chemosensors11050302
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 303: Recent Progresses in Plasmonic
           Biosensors for Point-of-Care (POC) Devices: A Critical Review

    • Authors: Caterina Serafinelli, Alessandro Fantoni, Elisabete C. B. A. Alegria, Manuela Vieira
      First page: 303
      Abstract: The recent progresses in the research of plasmonic phenomena and materials paved the route toward the development of optical sensing platforms based on metal nanostructures with a great potential to be integrated into point-of-care (POC) devices for the next generation of sensing platforms, thus enabling real-time, highly sensitive and accurate diagnostics. In this review, firstly, the optical properties of plasmonic metal nanoparticles will be illustrated, whereafter the engineering of POC platforms, such as microfluidics and readout systems, will be considered with another critical point which is surface functionalization. Attention will also be given to their potential in multiplexed analysis. Finally, the limitations for effective implementation in real diagnostics will be illustrated with a special emphasis on the latest trend in developing cutting-edge sensing systems.
      Citation: Chemosensors
      PubDate: 2023-05-19
      DOI: 10.3390/chemosensors11050303
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 304: Chemical Sensor Based on
           Piezoelectric/Triboelectric Nanogenerators: A Review of the Modular Design

    • Authors: Zequan Zhao, Qiliang Zhu, Yin Lu, Yajun Mi, Xia Cao, Ning Wang
      First page: 304
      Abstract: Piezoelectric and triboelectric nanogenerators (P-TENGs) have emerged as promising technologies for converting mechanical energy into electrical energy, with potential applications in self-powered wearable and environmental monitoring devices. Modular design in P-TENGs, characterized by the flexible assembly and customization of device components, enables the development of sustainable and versatile chemical sensors. In this review, we focus on the role of modularity in P-TENG-based chemical sensing, discussing how it enhances design flexibility, sensing versatility, scalability, and integration with other technologies. We explore the various strategies for functionalizing P-TENGs with specific recognition elements, facilitating selective and sensitive detection of target chemicals such as gases, biochemicals, or biomolecules. Furthermore, we examine the integration of modular P-TENGs with energy storage devices, signal conditioning circuits, and wireless communication modules, highlighting the potential for creating advanced, self-powered sensing systems. Finally, we address the challenges and future directions in the development of modular P-TENG-based chemical sensors (PCS and TCS), emphasizing the importance of improving selectivity, stability, and reproducibility for practical applications.
      Citation: Chemosensors
      PubDate: 2023-05-19
      DOI: 10.3390/chemosensors11050304
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 305: Rhodamine Derivative-Linked
           Silica-Coated Upconverting Nanophosphor (NaYF4: Yb3+/Er3+@SiO2-RBDA) for
           Ratiometric, Ultrasensitive Chemosensing of Pb2+ Ions

    • Authors: Jitender Kumar, Indrajit Roy
      First page: 305
      Abstract: Lead (Pb2+) ions are considered as one of the primary environmental pollutants and have a profound effect on human health. In this work, we have developed a hybrid organic–inorganic optical nanochemosensor for selective and ultrasensitive detection of Pb2+ ions based on energy transfer (ET), involving a Pb2+ sensitive rhodamine-derived named (E)-4-(((3′,6′-bis(diethylamino)-3-oxospiro[isoindoline-1,9′-xanthen]-2-yl)imino)methyl)benzaldehyde represented as RBDA, covalently linked with silica coated upconverting nanophosphors (UCNPs). The UCNPs emit visible light after being excited by NIR light, activating the Pb2+ coordinated RBDA (fluorescent probe). When Pb2+ ions were added, a yellow emission band at about 588 nm formed in upconverting photoluminescence spectra, whereas the strength of green emission at about 542 nm reduced upon excitation of 980 nm laser, indicating the energy transfer from UCNP to RBDA-Pb2+ complex. The concentration of Pb2+ ions directly affects how well the probe reabsorbs the green emission of the nanophosphor, thus enabling the ratiometric chemosensing. With a detection limit of 20 nM in aqueous, the resulting ET-based nochemosensor can also preferentially detect Pb2+ despite the presence of other ions. Owing to the minimal autofluorescence and the great penetration depth of NIR light and special optical features of UCNPs, this is a promising approach for sensitive and in-depth detection of Pb2+ ions in a complex ecological and biological specimen.
      Citation: Chemosensors
      PubDate: 2023-05-19
      DOI: 10.3390/chemosensors11050305
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 306: Additive Manufacturing Sensor for Stress
           Biomarker Detection

    • Authors: Vinicius A. O. P. da Silva, Jéssica S. Stefano, Cristiane Kalinke, Juliano A. Bonacin, Bruno C. Janegitz
      First page: 306
      Abstract: This work presents a new additive manufacturing electrochemical device with conductive graphene and polylactic acid (PLA) filament and its application for epinephrine sensing. A three-electrode configuration based on a screen-printed electrode architecture and an easy-to-connect connector was designed. The sensor surface was chemically treated with dimethylformamide (DMF) to remove the insulating thermoplastic and expose the graphene binding groups. The scanning electron microscopy (SEM) results showed that the surface PLA was removed and the graphene nanofibers exposed, which corroborated the X-ray diffraction spectra (XRD). As a proof of concept, the G-PLA electrode was applied for the determination of epinephrine in human blood samples by square wave voltammetry with a linear range from 4.0 to 100 µmol L−1 and a limit of detection of 0.2 µmol L−1. Based on the results obtained and sensor application, 3D-printed G-PLA proved an excellent choice for epinephrine sensing purposes.
      Citation: Chemosensors
      PubDate: 2023-05-20
      DOI: 10.3390/chemosensors11050306
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 307: A Laser-Printed Surface-Enhanced
           Photoluminescence Sensor for the Sub-Nanomolar Optical Detection of
           Mercury in Water

    • Authors: Yulia Borodaenko, Stanislav Gurbatov, Evgeny Modin, Aleksandr Chepak, Mikhail Tutov, Aleksandr Mironenko, Aleksandr Kuchmizhak
      First page: 307
      Abstract: Here, we report a novel, easy-to-implement scalable single-step procedure for the fabrication of a solid-state surface-enhanced photoluminescence (SEPL) sensor via the direct femtosecond (fs) laser patterning of monocrystalline Si wafers placed under the layer of functionalizing solution simultaneously containing a metal salt precursor (AgNO3) and a photoluminescent probe (d114). Such laser processing creates periodically modulated micro- and nanostructures decorated with Ag nanoparticles on the Si surface, which effectively adsorbs and retains the photoluminescent sensor layer. The SEPL effect stimulated by the micro- and nanostructures formed on the Si surface localizing pump radiation within the near-surface layer and surface plasmons supported by the decorating Ag nanoparticles is responsible for the intense optical sensory response modulated by a small amount of analyte species. The produced SEPL sensor operating within a fluidic device was found to detect sub-nanomolar concentrations of Hg2+ in water which is two orders of magnitude lower compared to this molecular probe sensitivity in solution. The fabrication technique is upscalable, inexpensive, and flexible regarding the ability to the control surface nano-morphology, the amount and type of loading noble-metal nanoparticles, as well as the type of molecular probe. This opens up pathways for the on-demand development of various multi-functional chemosensing platforms with expanded functionality.
      Citation: Chemosensors
      PubDate: 2023-05-20
      DOI: 10.3390/chemosensors11050307
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 308: Organic Luminescent Sensor for
           Mercury(II) and Iron(III) Ions in Aqueous Solutions

    • Authors: Sofian Kanan, Aysha Shabnam, Ahmed A. Mohamed, Imad A. Abu-Yousef
      First page: 308
      Abstract: The substrate N1, N3, N5-tris(2-hydroxyphenyl)benzene-1,3,5-tricarboxamide (Sensor A) was prepared in the reaction of 1,3,5-benzenetricarboxylic acid (trimesic acid) and o-aminophenol in ethanol. The prepared organic sensor fulfills the chemiluminescent requirements including a luminophore, spacer, and suitable binding receptor that distress the probe’s luminescent features, providing selective and sensitive detection of mercury and iron ions in aqueous solutions. The sensor selectively detects mercury and iron ions in a water matrix containing various metal ions, including sodium, calcium, magnesium, zinc, and nickel. Strong and immediate binding was observed between mercury ions and the substrate at pH 7.0 with a binding affinity toward Hg2+ 9-fold higher than that observed for iron sensor binding affinity, which makes the substrate a distinctive luminescence sensor for mercury detection at ambient conditions. The sensor shows a linear response toward Hg2+ in the concentration range from 50 ppb to 100 ppm (2.0 × 10−8 to 4.2 × 10−5 M) with a limit of detection of 2 ppb (1.0 × 10−8 M). Further, Sensor A provides linear detection for iron ions in the range from 10 ppb to 1000 ppm (1.5 × 10−8 to 1.5 × 10−3 M). The measured adsorption capacity of Sensor A toward mercury ions ranged from 1.25 to 1.97 mg/g, and the removal efficiency from water samples reached 98.8% at pH 7.0. The data demonstrate that Sensor A is an excellent probe for detecting and removing mercury ions from water bodies.
      Citation: Chemosensors
      PubDate: 2023-05-20
      DOI: 10.3390/chemosensors11050308
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 309: A Novel Nanoplatform Based on
           Biofunctionalized MNPs@UCNPs for Sensitive and Rapid Detection of Shigella

    • Authors: Yaqi Song, Min Chen, Zhongyu Yan, Lu Han, Leiqing Pan, Kang Tu
      First page: 309
      Abstract: Shigella, a typical and fatal foodborne pathogen with strong infectivity and survivability in foodstuff, demands a simple and sensitive detecting method. In this study, we reported a novel nanoplatform based on biofunctionalized magnetic nanoparticles (MNPs) modified upconversion nanoparticles (UCNPs) for rapid and specific determination of Shigella. Due to base pairing, Shigella aptamer-functionalized horseradish peroxidase (HRP) combined with complementary strand-modified MNPs@UCNPs. In the absence of Shigella, HRP associated with MNPs@UCNPs were magnetically separated, and colorless 3,3′,5,5′-tetramethylbenzidine (TMB) was oxidized into blue oxTMB. The overlap between oxTMB’s absorption peak and MNPs@UCNPs’ emission peak caused the fluorescence quenching at 545 nm. The MNPs@UCNPs fluorescence biosensor was achieved to detect Shigella in 1 h, with a limit of detection of 32 CFU/mL. This work showed a rapid and specific sensing platform and produced satisfactory chicken sample results.
      Citation: Chemosensors
      PubDate: 2023-05-20
      DOI: 10.3390/chemosensors11050309
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 310: Quantitative Structure-Activity
           Relationship of Fluorescent Probes and Their Intracellular Localizations

    • Authors: Seong-Hyeon Park, Hong-Guen Lee, Xiao Liu, Sung Kwang Lee, Young-Tae Chang
      First page: 310
      Abstract: The development of organelle-specific fluorescent probes has been impeded by the absence of a comprehensive understanding of the relationship between the physicochemical properties of fluorescent probes and their selectivity towards specific organelles. Although a few machine learning models have suggested several physicochemical parameters that control the target organelle of the probes and have attempted to predict the target organelles, they have been challenged by low accuracy and a limited range of applicable organelles. Herein, we report a multi-organelle prediction QSAR model that is capable of predicting the destination of probes among nine categories, including cytosol, endoplasmic reticulum, Golgi body, lipid droplet, lysosome, mitochondria, nucleus, plasma membrane, and no entry. The model is trained using the Random Forest algorithm with a dataset of 350 organelle-specific fluorescent probes and 786 descriptors, and it is able to predict the target organelles of fluorescent probes with an accuracy of 75%. The MDI analysis of the model identifies 38 key parameters that have a significant impact on the organelle selectivity of the probes, including LogD, pKa, hydrophilic-lipophilic balance (HLB), and topological polar surface area (TPSA). This prediction model may be useful in developing new organelle-specific fluorescent probes by providing crucial variables that determine the destination of the probes.
      Citation: Chemosensors
      PubDate: 2023-05-22
      DOI: 10.3390/chemosensors11050310
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 311: Electrochemical Mercury Biosensor Based
           on Electrocatalytic Properties of Prussian Blue and Inhibition of Catalase

    • Authors: Povilas Virbickas, Narvydas Dėnas, Aušra Valiūnienė
      First page: 311
      Abstract: This paper presents a detailed study of a novel type of electrochemical mercury ion (Hg2+) biosensor developed by combining Prussian blue (PB) and catalase (Cat). The simultaneous PB-catalyzed reduction of hydrogen peroxide and the inhibition of catalase by Hg2+ ions were used as the working principle of the biosensor. The biosensor described in this research was capable of detecting Hg2+ ions at relatively low potentials (+0.2 V vs. Ag AgCl, KClsat) using chronoamperometry and a fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS). Linear ranges of 0.07 mM–3 mM and 0.13 mM–0.80 mM of Hg2+ ions were obtained using amperometric and impedimetric techniques, respectively. In the course of this work, an amperometric study of the Hg2+ ion biosensor was also carried out on a real sample (tap water containing Hg2+ ions).
      Citation: Chemosensors
      PubDate: 2023-05-22
      DOI: 10.3390/chemosensors11050311
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 312: Modeling and Simulation of a TFET-Based
           Label-Free Biosensor with Enhanced Sensitivity

    • Authors: Sagarika Choudhury, Krishna Lal Baishnab, Koushik Guha, Zoran Jakšić, Olga Jakšić, Jacopo Iannacci
      First page: 312
      Abstract: This study discusses the use of a triple material gate (TMG) junctionless tunnel field-effect transistor (JLTFET) as a biosensor to identify different protein molecules. Among the plethora of existing types of biosensors, FET/TFET-based devices are fully compatible with conventional integrated circuits. JLTFETs are preferred over TFETs and JLFETs because of their ease of fabrication and superior biosensing performance. Biomolecules are trapped by cavities etched across the gates. An analytical mathematical model of a TMG asymmetrical hetero-dielectric JLTFET biosensor is derived here for the first time. The TCAD simulator is used to examine the performance of a dielectrically modulated label-free biosensor. The voltage and current sensitivity of the device and the effects of the cavity size, bioanalyte electric charge, fill factor, and location on the performance of the biosensor are also investigated. The relative current sensitivity of the biosensor is found to be about 1013. Besides showing an enhanced sensitivity compared with other FET- and TFET-based biosensors, the device proves itself convenient for low-power applications, thus opening up numerous directions for future research and applications.
      Citation: Chemosensors
      PubDate: 2023-05-22
      DOI: 10.3390/chemosensors11050312
      Issue No: Vol. 11, No. 5 (2023)
  • Chemosensors, Vol. 11, Pages 239: Combinatorial Material Strategy:
           Parallel Synthesis and High-Throughput Screening of WO3 Nanoplates
           Decorated with Noble Metals for VOCs Sensor

    • Authors: Yanjia Ma, Ming Hou, Li Yang, Jiyun Gao, Guozhu Zhang, Ronghui Guo, Shenghui Guo
      First page: 239
      Abstract: In this study, we report on the rapid preparation of WO3 nanoplates decorated with noble metals and evaluate their gas-sensing performance using a high-throughput screening technique. The incorporation of Pd significantly enhanced the gas-sensing properties, and, among all of the samples tested, the WO3 nanoplate containing 0.3 mol% Pd exhibited the highest response to 100 ppm xylene at 250 °C (Ra/Rg = 131.2), which was almost 56 times greater than that of the pure WO3 sample. Additionally, this sample demonstrated rapid response and recovery times (τresponse = 3.9 s and τrecovery = 189.2 s, respectively). The nanoplate samples were also classified and screened using cluster analysis, and the selected samples were optimized for use in a sensor array. By applying principal component analysis and Fisher discriminant analysis, four typical gases were identified and a potential sensitization mechanism was elucidated.
      Citation: Chemosensors
      PubDate: 2023-04-11
      DOI: 10.3390/chemosensors11040239
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 240: Ag-ZnS Embedded Polymeric Receptors for
           the Recognition of Human Serum Albumin

    • Authors: Amara Nasrullah, Muhammad Zahid, Asghar Ali, Mirza Nadeem Ahmad, Adnan Mujahid, Tajamal Hussain, Usman Latif, Muhammad Imran Din, Adeel Afzal
      First page: 240
      Abstract: The detection of human serum albumin (HSA) is of significant clinical importance in disease diagnoses. In this work, polymer-based synthetic receptors are designed by incorporating Ag-ZnS microspheres in molecularly imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIPs) for the gravimetric detection of HSA. Among different compositions of Ag-ZnS@MIPs, MIPs having methacrylic acid and ethylene glycol dimethacrylate volume ratio of 3:2 exhibit enhanced HSA sensitivity in the concentration range of 5–200 ng/mL. A remarkably low threshold limit of detection (LOD = 0.364 ng/mL) is achieved with quartz crystal microbalance (QCM) based gravimetric sensors. Furthermore, the Ag-ZnS@MIPs/QCM sensors show high selectivity for HSA compared to other proteins, e.g., bovine serum albumin (BSA), glycoprotein, ribonuclease, and lysozyme. Hence, the gravimetric quantification of HSA realizes a highly sensitive, selective, and label-free detection mechanism with a limit of quantification down to 1.1 ng/mL.
      Citation: Chemosensors
      PubDate: 2023-04-12
      DOI: 10.3390/chemosensors11040240
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 241: Recent Advances in Small Molecular
           Fluorescence Probes for Fatty Liver Diseases

    • Authors: Bo Liu, Honghui Yin, Yaxiong Li, Guojiang Mao, Sheng Yang, Kai Zhang
      First page: 241
      Abstract: Fatty liver diseases are a spectrum of liver disorders consisting of the benign fatty liver, which could eventually lead to cirrhosis or even hepatocellular cancer (HCC) without timely treatment. Therefore, early diagnosis is crucial for fatty liver diseases. Liver biopsy is regarded as the gold standard in the diagnosis of fatty liver diseases. However, it is not recommended for routine use due to its invasiveness and complicated operation. Thus, it is urgent to diagnose fatty liver diseases with non-invasive and precise methods. In this regard, fluorescence imaging technology has attracted intensive attention and become a robust non-invasive method for fatty liver visualization, and a series of fluorescent probes are being intensively designed to track the biomarkers in fatty liver. In this brief review, the small molecular fluorescent probes employed in fatty liver are summarized, mainly focusing on the last four years. Moreover, current opportunities and challenges in the development of fluorescent probes for fatty liver will be highlighted.
      Citation: Chemosensors
      PubDate: 2023-04-12
      DOI: 10.3390/chemosensors11040241
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 242: In-Situ Formation of NiFe-MOF on Nickel
           Foam as a Self-Supporting Electrode for Flexible Electrochemical Sensing
           and Energy Conversion

    • Authors: Shuting Weng, Qi An, Yanchao Xu, Yang Jiao, Jianrong Chen
      First page: 242
      Abstract: Ni- and Fe-based metal-organic frameworks (NiFe-MOFs) have abundant valence states and have the potential to be used as bifunctional electrode materials. However, unannealed NiFe-MOFs are still not widely used in electrode materials, including electrochemical sensing, supercapacitors, and overall water splitting. In addition, the direct growth of active material on a conductive carrier has been developed as a binder-free strategy for electrode preparation. This strategy avoids the use of insulating binders and additional electrode treatments, simplifies the preparation process of the NiFe-MOFs, and improves the conductivity and mechanical stability of the electrode. Therefore, in this study, we employed a simple solvothermal method combined with an in situ growth technique to directly grow NiFe-MOF-X (X = 4, 8, 12) nanomaterials of different sizes and morphologies on nickel foam at low reaction temperatures and different reaction times. The NiFe-MOF-8 electrode exhibited high capacitive properties, with an area-specific capacitance of 5964 mF cm−2 at 2 mA cm−2 and excellent durability. On the other hand, NiFe-MOF-12 exhibited strong catalytic activity in electrocatalytic tests performed in a 1 M KOH aqueous solution, demonstrating hydrogen evolution reaction (η10 = 150 mV) and oxygen evolution reaction (η50 = 362 mV) activities. The electrochemical sensing tests demonstrated a good response to BPA. Overall, our results suggest that the direct growth of NiFe-MOFs on nickel foam using a simple solvothermal method combined with an in situ growth technique is a promising strategy.
      Citation: Chemosensors
      PubDate: 2023-04-13
      DOI: 10.3390/chemosensors11040242
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 243: Functionalized Three−Dimensional
           Graphene Containing Chitosan and Bovine Serum Albumin for Recognizing
           Chiral Drug Intermediates

    • Authors: Sha Li, Wenyan Yao, Licheng Xie, Yan Jiang
      First page: 243
      Abstract: Chiral enantiomer recognition has important research significance in the field of analytical chemistry research. At present, most prepared chiral sensors are used for recognizing amino acids, while they are rarely used in the identification of drug intermediates. This work found that combining CS and reduced graphene oxide can enhance conductivity, increasing the recognition effect by connecting CS with BSA. Based on the above preparation, a new type of chiral sensor (3D−rGO−CS−BSA) was synthesized for the identification of drug intermediates, including the 1−Boc−3−hydroxypyrrolidine enantiomer. An obvious difference was achieved (IR/IS = 2.82) in the oxidation peak currents between the two enantiomers. The detection limits of the R−enantiomer and S−enantiomer were 4.85 nM and 11.76 nM, respectively. The proposed electrochemical sensing platform also has better potential for detecting the percentage content of mixed chiral enantiomer drugs.
      Citation: Chemosensors
      PubDate: 2023-04-14
      DOI: 10.3390/chemosensors11040243
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 244: Electrochemical Sweat Sensors

    • Authors: Emanuel Bilbao, Octavio Garate, Theo Rodríguez Campos, Mariano Roberti, Mijal Mass, Alex Lozano, Gloria Longinotti, Leandro Monsalve, Gabriel Ybarra
      First page: 244
      Abstract: Sweat analysis by means of minimally invasive wearable sensors is considered a potentially disruptive method for assessing clinical parameters, with exciting applications in early medical diagnostics and high-performance sports. Electrochemical sensors and biosensors are especially attractive because of the possibility of the electronic integration of wearable devices. In this article, we review several aspects regarding the potentialities and present limitations of electrochemical sweat (bio)sensors, including: the main target analytes and their relationships with clinical conditions; most usual electrochemical techniques of transduction used according to the nature of the target analytes; issues connected to the collection of representative sweat samples; aspects regarding the associated, miniaturized electronic instrumentation used for signal processing and communication; and signal processing by machine learning.
      Citation: Chemosensors
      PubDate: 2023-04-14
      DOI: 10.3390/chemosensors11040244
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 245: A Novel Highly Sensitive
           Chemiluminescence Enzyme Immunoassay with Signal Enhancement Using
           Horseradish Peroxidase-Luminol-Hydrogen Peroxide Reaction for the
           Quantitation of Monoclonal Antibodies Used for Cancer Immunotherapy

    • Authors: Ibrahim A. Darwish, Nourah Z. Alzoman, Nehal N. Khalil
      First page: 245
      Abstract: The development and validation of a novel enhanced chemiluminescence enzyme immunoassay (CLEIA) with excellent sensitivity for the quantification of monoclonal antibodies (mAbs) used for immunotherapy of cancer are described in this paper for the first time. The 96-microwell plates were used for the assay procedures, which involved the non-competitive binding reaction to a specific antigen. The immune complex of the antigen-mAb formed on the internal surface of the plate wells was quantified by a novel chemiluminescence (CL)-producing horseradish peroxidase (HRP) reaction. The reaction employed 4-(imidazol-1-yl)phenol (IMP) as a highly potent signal enhancer for the HRP-luminol–hydrogen peroxide (H2O2) CL reaction. The proposed CLEIA was developed for bevacizumab (BEV), as a representative example for mAbs. The CLEIA was validated in accordance with the immunoassay validation for bioanalysis standards, and all of the validation criteria were met. The assay’s limit of detection (LOD) and limit of quantitation (LOQ) were 9.3 and 28.2 pg mL−1, respectively, with a working dynamic range of 10–400 pg mL−1. The assay enables the accurate and precise quantitation of mAbs in human plasma samples without any interference from endogenous substances and/or plasma matrix. The novel CLEIA was compared in terms of dynamic range and sensitivity with other pre-validated enzyme-linked immunosorbent assay (ELISA) using HRP/colorimetric substrate as a detection system and the observed differences were explained. The CLEIA protocol’s ease of use, high throughput, and simplicity allows to analyze numerous samples in clinical settings. The proposed CLEIA has a significant benefit in the assessment of mAbs in clinical settings for the evaluation of their pharmacokinetics, pharmacodynamics, therapeutic drug monitoring, and refining their safety profiles, opening a new era for a better understanding of pharmacodynamics at the cellular level.
      Citation: Chemosensors
      PubDate: 2023-04-14
      DOI: 10.3390/chemosensors11040245
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 246: Sensitive Evanescence-Field Waveguide
           Interferometer for Aqueous Nitro-Explosive Sensing

    • Authors: Wen Wang, Guowei Deng, Zhanwei Hu, Kaixin Chen, Jieyun Wu
      First page: 246
      Abstract: The development of novel chemical nitro-explosive sensors with high sensitivity, low cost and a compact size is essential for homeland security, environmental protection and addressing military challenges. Polymeric optical waveguides based on refractive index sensing are widely used in biochemical detection due to their advantages of large-scale integration, low cost, high sensitivity and anti-electromagnetic interference. In this study, we designed and fabricated a polymer waveguide Mach–Zehnder interferometer (MZI) sensor to detect 2,4-dinitrotoluene (DNT) in water. One phase shifter of the MZI waveguide was functionalized by coating a thin cladding layer of polycarbonate with dipolar chromophores and used as the sensing arm; the other arm was coated with passive epoxy resin cladding and used as the reference arm. The phase difference between the two arms of the MZI was modulated using the refractive index (RI) change in the polycarbonate cladding when dipolar chromophores interacted with electro-deficient DNT. The theoretical sensitivity of the designed MZI can reach up to 24,696 nm/RIU. When used for explosive detection, our fabricated sensor had a maximum wavelength shift of 4.465 nm and good linear relation, with an R2 of 0.96 between the wavelength shift and a concentration ranging from 3.5 × 10−5 to 6.3 × 10−4 mol/L. The sensitivity of our device was 6821.6 nm/(mol/L). The design of an unbalanced MZI sensor, together with the sensing material, provides a new approach to using low-cost, compact and highly sensitive devices for in-field explosive detection.
      Citation: Chemosensors
      PubDate: 2023-04-15
      DOI: 10.3390/chemosensors11040246
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 247: Sensitive and Reversible Ammonia Gas
           Sensor Based on Single-Walled Carbon Nanotubes

    • Authors: Abniel Machín, María Cotto, José Duconge, Carmen Morant, Florian I. Petrescu, Francisco Márquez
      First page: 247
      Abstract: The present study reports on the fabrication and performance of ammonia sensors based on single-walled carbon nanotubes (SWCNTs) coated with gold nanoparticles (AuNPs). The AuNPs were incorporated onto the SWCNTs using two different methods: sputtering and chemical deposition. The sensors were exposed to controlled concentrations of ammonia at two temperatures, namely, 25 °C and 140 °C, and their response was monitored through successive cycles of ammonia exposure (0.5 ppm and 1.0 ppm) and nitrogen purging. The results demonstrate that the sputtering-based deposition of the AuNPs on SWCNTs led to the best sensor performance, characterized by a rapid increase in resistance values (tresp = 12 s) upon exposure to ammonia and an efficient recovery at 140 °C (trec = 52 s). By contrast, the sensor with chemically impregnated AuNPs exhibited a slower response time (tresp = 25 s) and the same recovery time (trec = 52 s). Additionally, a novel device was developed that combined MoS2-AuNPs (sputtering)-SWCNTs. This sensor was obtained by impregnating nanosheets of MoS2 onto AuNPs (sputtering)-SWCNTs showing improved sensor performance compared to the devices with only AuNPs. In this case, the sensor exhibited a better behavior with a faster recovery of resistance values, even at room temperature. Overall, the study provides valuable insights into the fabrication and optimization of SWCNT-based ammonia sensors for various applications, particularly in detecting and quantifying small amounts of ammonia (concentrations below 1 ppm).
      Citation: Chemosensors
      PubDate: 2023-04-16
      DOI: 10.3390/chemosensors11040247
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 248: The Human Nose as a Chemical Sensor in
           the Perception of Coffee Aroma: Individual Variability

    • Authors: Roberto Crnjar, Paolo Solari, Giorgia Sollai
      First page: 248
      Abstract: The flavor of foods and beverages is generally composed of a mixture of volatile compounds, however not all the molecules that form an aroma are sensorially relevant. The odor-active compounds present in a mixture are different for each subject, both in quantitative and qualitative terms. This means that the ability of the human nose to act as a chemical sensor varies among individuals. In this study, we used the headspace of roasted coffee beans as a complex olfactory stimulus and, by means of the coupled Gas Chromatography-Olfactometry (GC-O) technique, the single components of coffee flavor were separated. Each subject, previously classified for his/her olfactory status (normosmic, hyposmic or anosmic) by means of the Sniffin’ Sticks battery (composed of Threshold, Discrimination and Identification subtests), had to identify and evaluate each smelled molecule. The results show that the individual ability to detect individual compounds during the GC-O experiments and the odor intensity reported during the sniffing of pen #10 (the pen of the identification test) containing coffee aroma were related to TDI olfactory status (based on the score obtained from the sum composed of Threshold, Discrimination and Identification scores). We also found that the number of total molecules and of molecules smelling of coffee is linearly related to the TDI olfactory score. Finally, the odor intensity reported when sniffing pen #10 containing coffee aroma is positively correlated with the number of molecules detected and the average intensity reported. In conclusion, our findings show that the human perception of both individual compounds and complex odors is strongly conditioned by the olfactory function of subjects.
      Citation: Chemosensors
      PubDate: 2023-04-17
      DOI: 10.3390/chemosensors11040248
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 249: Pyranine Immobilized on
           Aminopropyl-Modified Mesoporous Silica Film for Paraquat Detection

    • Authors: Sudarat Sombatsri, Krittanun Deekamwong, Pongtanawat Khemthong, Sanchai Prayoonpokarach
      First page: 249
      Abstract: An optical sensor based on pyranine immobilized on aminopropyl-modified mesoporous silica films was developed for paraquat detection in aqueous solutions. An electrochemically assisted self-assembly method was used to deposit mesoporous silica film on fluorine-doped tin oxide glass. The obtained films were modified with various concentrations of 3-aminopropyl triethoxysilane (APTES) before the immobilization of pyranine. Cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and fluorescence spectroscopy were used to characterize the films. Pyranine-immobilized films gave an emission at 506 nm with an excitation at 450 nm. The fluorescence signal was quenched in the presence of paraquat. The films modified with 3% APTES provided the optimum response to paraquat. The developed films had a linear response to paraquat in the concentration range of 1 to 10 ppm at the optimum conditions, with a detection limit of 0.80 ppm. The developed method was used to quantify paraquat in sugarcane peel and tap water samples with satisfactory results.
      Citation: Chemosensors
      PubDate: 2023-04-17
      DOI: 10.3390/chemosensors11040249
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 250: Enhancing the Potentiometric H2 Sensing
           of Pr0.1Ce0.9O2−δ Using Fe2O3 Surface Modification

    • Authors: Liang Wang, Jianxin Yi
      First page: 250
      Abstract: Monitoring the concentration of hydrogen is very important as it is a flammable and explosive gas. Non-Nernstian potentiometric hydrogen sensors hold promising potentials for the sensitive detection of hydrogen. This paper reports the improved H2-sensing performance of a mixed oxide ion-electron conducting (MIEC) Pr0.1Ce0.9O2−δ (PCO) electrode using Fe2O3 surface modification. The Fe2O3-modified PCO exhibited a high response of −184.29 mV to 1000 ppm H2 at 450 °C. The response values exhibited a linear or logarithmic dependence on the H2 concentration for below or above 20 ppm, respectively. A sensitivity of −74.9 mV/decade in the concentration range of 20–1000 ppm was achieved, and the theoretical limit of detection was calculated to be 343 ppb. Moreover, a power-law relationship between the response time and the concentration value was also found. Electrochemical impedance analyses revealed that the excellent H2-sensing performance may be attributed to the large ratio of the electrochemical activity of the hydrogen oxidation reaction (HOR) over the oxygen exchange reaction (OER). In addition, the distribution of relaxation time (DRT) results reveal that the enhanced electrochemical kinetics caused by H2 presence in air is mainly related to acceleration of the electrode surface processes.
      Citation: Chemosensors
      PubDate: 2023-04-17
      DOI: 10.3390/chemosensors11040250
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 251: Metal Oxide Semiconductor Gas Sensors
           for Lung Cancer Diagnosis

    • Authors: Guangyao Li, Xitong Zhu, Junlong Liu, Shuyang Li, Xiaolong Liu
      First page: 251
      Abstract: Lung cancer is the most prevalent severe illness in both sexes and all ages and the leading cause of cancer-related deaths globally. Late-stage diagnosis is the primary cause of its high mortality rate. Therefore, the management of lung cancer needs early-stage screening. Breath analysis is a non-invasive, low-cost, and user-friendly approach to diagnosing lung cancer. Among the various types of breath sensors, MOS gas sensors are preferred due to their high gas responses, fast response times, robustness, and lower price. This review focuses on the critical role of MOS gas sensors in detecting VOCs in lung cancer patients’ exhaled breath. It introduces the basic working mechanism of MOS gas-sensitive materials, summarizes some high-performance MOS materials suitable for detecting potential lung cancer biomarkers and provides performance enhancement strategies. The review also briefly introduces the sensor array and its pattern recognition algorithm. Finally, we discuss the challenges in developing MOS gas sensors for lung cancer screening and present the prospect of using the e-nose for large-scale early lung cancer screening.
      Citation: Chemosensors
      PubDate: 2023-04-17
      DOI: 10.3390/chemosensors11040251
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 252: Quantum Dots-Sensitized High Electron
           Mobility Transistor (HEMT) for Sensitive NO2 Detection

    • Authors: Zhixiang Hu, Licheng Zhou, Long Li, Binzhou Ying, Yunong Zhao, Peng Wang, Huayao Li, Yang Zhang, Huan Liu
      First page: 252
      Abstract: Colloidal quantum dots (CQDs) are gaining increasing attention for gas sensing applications due to their large surface area and abundant active sites. However, traditional resistor-type gas sensors using CQDs to realize molecule recognition and signal transduction at the same time are associated with the trade-off between sensitivity and conductivity. This limitation has restricted their range of practical applications. In this study, we propose and demonstrate a monolithically integrated field-effect transistor (FET) gas sensor. This novel FET-type gas sensor utilizes the capacitance coupling effect of the CQD sensing film based on a floating gate, and the quantum capacitance plays a role in the capacitance response of the CQD sensing film. By effectively separating the gate sensing film from the two-dimensional electron gas (2DEG) conduction channel, the lead sulfide (PbS) CQD gate-sensitized FET gas sensor offers high sensitivity, a high signal-to-noise ratio, and a wide range, with a real-time response of sub-ppb NO2. This work highlights the potential of quantum dot-sensitized FET gas sensors as a practical solution for integrated gas sensor chip applications using CQDs.
      Citation: Chemosensors
      PubDate: 2023-04-18
      DOI: 10.3390/chemosensors11040252
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 253: Precise Integration of Polymeric Sensing
           Functional Materials within 3D Printed Microfluidic Devices

    • Authors: Jaione Etxebarria-Elezgarai, Maite Garcia-Hernando, Lourdes Basabe-Desmonts, Fernando Benito-Lopez
      First page: 253
      Abstract: This work presents a new architecture concept for microfluidic devices, which combines the conventional 3D printing fabrication process with the stable and precise integration of polymeric functional materials in small footprints within the microchannels in well-defined locations. The approach solves the assembly errors that normally occur during the integration of functional and/or sensing materials in hybrid microfluidic devices. The method was demonstrated by embedding four pH-sensitive ionogel microstructures along the main microfluidic channel of a complex 3D printed microfluidic device. The results showed that this microfluidic architecture, comprising the internal integration of sensing microstructures of diverse chemical compositions, highly enhanced the adhesion force between the microstructures and the 3D printed microfluidic device that contains them. In addition, the performance of this novel 3D printed pH sensor device was investigated using image analysis of the pH colour variations obtained from photos taken with a conventional camera. The device presented accurate and repetitive pH responses in the 2 to 12 pH range without showing any type of device deterioration or lack of performance over time.
      Citation: Chemosensors
      PubDate: 2023-04-19
      DOI: 10.3390/chemosensors11040253
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 254: Disposable Sensor with Copper-Loaded
           Carbon Nanospheres for the Simultaneous Determination of Dopamine and

    • Authors: Sivaguru Jayaraman, Thenmozhi Rajarathinam, Seung-Cheol Chang
      First page: 254
      Abstract: A novel electrochemical sensor based on Cu-loaded carbon nanospheres (Cu–CNSs) was designed and fabricated. Initially, the CNSs were synthesized using a natural or inexpensive carbon source (dark brown sugar), and Cu was loaded to enhance the electrocatalytic properties of the material. Subsequently, the synthesized Cu–CNSs were modified onto a screen-printed carbon electrode (SPCE), termed Cu–CNS/SPCE, to simultaneously detect the biomarkers dopamine (DA) and melatonin (MT) through differential pulse voltammetry. The surface characterization of the Cu–CNSs confirmed the formation of carbon spheres and Cu nanoparticles covering the spheres. Electrochemical studies showed that the Cu–CNS/SPCE had a high selectivity and sensitivity toward DA and MT, with a significant peak separation of 0.502 V. The two linear ranges of DA were 0.125–20 μM and 20–100 μM and the linear range of MT was 1.0–100 μM, with corresponding detection limits of 0.34 μM and 0.33 μM (S/N = 3), respectively. The quantification limits for DA and MT were 2.19 and 1.09 μM (S/N = 10), respectively. The sensor performance is attributed to the high conductivity and large, electrochemically active surface area of the Cu–CNS. In human serum samples, the Cu–CNS/SPCE exhibited good selectivity and satisfactory reproducibility for the simultaneous determination of DA and MT.
      Citation: Chemosensors
      PubDate: 2023-04-19
      DOI: 10.3390/chemosensors11040254
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 255: LFA: The Mysterious Paper-Based
           Biosensor: A Futuristic Overview

    • Authors: Saumitra Singh, Mohd. Rahil Hasan, Akshay Jain, Roberto Pilloton, Jagriti Narang
      First page: 255
      Abstract: Lateral flow assay (LFA) is emerging as one of the most popular paper-based biosensors in the field of the diagnostic industry. LFA fills all the gaps between diagnosis and treatment as it provides beneficial qualities to users such as quick response, Point-of-care appeal, early detection, low cost, and effective and sensitive detections of various infectious diseases. These benefits increase LFA’s dependability for disease management because rapid and accurate disease diagnosis is a prerequisite for effective medication. Only 2% of overall healthcare expenditures, according to Roche Molecular Diagnostics, are spent on in vitro diagnostics, even though 60% of treatment choices are based on this data. To make LFA more innovative, futuristic plans have been outlined in many reports. Thus, this review reports on very knowledgeable literature discussing LFA and its development along with recent futuristic plans for LFA-based biosensors that cover all the novel features of the improvement of LFA. LFA might therefore pose a very significant economic success and have a significant influence on medical diagnosis.
      Citation: Chemosensors
      PubDate: 2023-04-19
      DOI: 10.3390/chemosensors11040255
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 256: Tesla Valve Microfluidics: The Rise of
           Forgotten Technology

    • Authors: Agnes Purwidyantri, Briliant Adhi Prabowo
      First page: 256
      Abstract: The Tesla valve (TV), a valvular conduit invented by Nicola Tesla over a century ago, has recently acquired significant attention and application in various fields because of the growing interest in microfluidics and nanofluidics. The unique architecture of TV characterized by an asymmetrical design and an arc-shaped channel has long been an intriguing yet underrated design for building a passive component in a microfluidic system. While previously regarded as a technology without significant use, TV structures have been implemented in thermal manipulation fluidics, micromixers and micropumps, benefitting the advancement of urgently demanding technology in various areas, such as in biomedical diagnostics through wearable electronics and medical instruments, lab on a chip, chemosensors and in application toward sustainable technology manifested in fuel cell devices. This article presents the first comprehensive review of TV structures in the literature, which has seen significant growth in the last two years. The review discusses typical TV structures, including single-stage TV (STV), multistage TV (MSTV), and TV derivatives (TVD), along with their characteristics and potential applications. The designs of these structures vary based on their intended applications, but all are constructed based on the fundamental principle of the TV structure. Finally, future trends and potential applications of TV structures are summarized and discussed. This topical review provides a valuable reference for students, early-career scientists, and practitioners in fluidic devices, particularly those interested in using TV structures as passive components.
      Citation: Chemosensors
      PubDate: 2023-04-20
      DOI: 10.3390/chemosensors11040256
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 257: Advances in a Microwave Sensor-Type
           Interdigital Capacitor with a Hexagonal Complementary Split-Ring Resonator
           for Glucose Level Measurement

    • Authors: Supakorn Harnsoongnoen, Benjaporn Buranrat
      First page: 257
      Abstract: This study involved the creation and assessment of a microwave sensor to measure glucose levels in aqueous solutions without invasiveness. The sensor design utilized a planar interdigital capacitor (IDC) loaded with a hexagonal complementary split-ring resonator (HCSRR). The HCSRR was chosen for its ability to generate a highly intense electric field that is capable of detecting variations in the dielectric characteristics of the specimen. A chamber tube was used to fill glucose solutions at the sensor’s sensitive area, and changes in the device’s resonance frequency (Fr) and reflection coefficient (S11) were used to measure glucose levels. Fitting formulas were developed to analyze the data, and laboratory tests showed that the sensor could accurately measure glucose levels within a range of 0–150 mg/dL. At a concentration of 37.5 mg/dL, the sensitivity based on S11 and Fr reached maximum values of 10.023 dB per mg/dL and 1.73 MHz per mg/dL, respectively. This implies that the sensor put forward has the possibility of being utilized in medical settings for the monitoring of glucose levels.
      Citation: Chemosensors
      PubDate: 2023-04-20
      DOI: 10.3390/chemosensors11040257
      Issue No: Vol. 11, No. 4 (2023)
  • Chemosensors, Vol. 11, Pages 258: MXene/NiO Composites for
           Chemiresistive-Type Room Temperature Formaldehyde Sensor

    • Authors: Baoyu Huang, Xinwei Tong, Xiangpeng Zhang, Qiuxia Feng, Marina N. Rumyantseva, Jai Prakash, Xiaogan Li
      First page: 258
      Abstract: In this work, MXene/NiO-composite-based formaldehyde (HCHO) sensing materials were successfully synthesized by an in situ precipitation method. The heterostructures between the MXene and NiO nanoparticles were verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The HCHO sensing performance of the MXene/NiO-based chemiresistive-type sensors was investigated. Compared to pure MXene and NiO materials, the sensing performance of the MXene/NiO-P2-based sensor to HCHO gas at room temperature was significantly enhanced by the formation of MXene/NiO heterojunctions. The response of the MXene/NiO-P2 sensor to 50 ppm HCHO gas was 8.8, which was much higher than that of the pure MXene and NiO. At room temperature, the detectable HCHO concentration of the MXene/NiO-P2-based sensor was 1 ppm, and the response and recovery time to 2 ppm HCHO was 279 s and 346 s, respectively. The MXene/NiO-P2 sensor also exhibited a good selectivity and a long-term stability to HCHO gas for 56 days. The in situ Fourier transform infrared (FTIR) spectra of the MXene/NiO-P2 sensor, when exposed to HCHO gas at different times, were investigated to verify the adsorption reaction products of HCHO molecules.
      Citation: Chemosensors
      PubDate: 2023-04-21
      DOI: 10.3390/chemosensors11040258
      Issue No: Vol. 11, No. 4 (2023)
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