for Journals by Title or ISSN
for Articles by Keywords
  Subjects -> CHEMISTRY (Total: 904 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (638 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (48 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (638 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 29)
ACS Catalysis     Hybrid Journal   (Followers: 49)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 27)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 322)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 6)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 62)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 77)
Advances in Chemical Science     Open Access   (Followers: 20)
Advances in Chemistry     Open Access   (Followers: 25)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20)
Advances in Drug Research     Full-text available via subscription   (Followers: 25)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 27)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 4)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
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: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 32)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 15)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 185)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 268)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 34)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 3)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 378)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
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: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 137)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 19)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     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: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 11)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 25)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 13)
Cellulose     Hybrid Journal   (Followers: 12)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 75)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 27)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 216)
Chemical Science     Open Access   (Followers: 28)
Chemical Technology     Open Access   (Followers: 35)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 58)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 22)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 33)
Chemistry & Industry     Hybrid Journal   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 176)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 46)
Chemistry of Materials     Hybrid Journal   (Followers: 282)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 11)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Cogent Chemistry     Open Access   (Followers: 2)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 23)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 1)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 7)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 8)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal   (Followers: 1)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 9)
Current Science     Open Access   (Followers: 75)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 2)
Dalton Transactions     Full-text available via subscription   (Followers: 26)
Detection     Open Access   (Followers: 4)

        1 2 3 4 | Last

Journal Cover
Journal Prestige (SJR): 0.829
Citation Impact (citeScore): 4
Number of Followers: 2  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2079-6374
Published by MDPI Homepage  [216 journals]
  • Biosensors, Vol. 9, Pages 7: Characterization and Inkjet Printing of an
           RNA Aptamer for Paper-Based Biosensing of Ciprofloxacin

    • Authors: Jeannine Jaeger, Florian Groher, Jacqueline Stamm, Dieter Spiehl, Johannes Braun, Edgar Dörsam, Beatrix Suess
      First page: 7
      Abstract: The excessive use of antibiotics in food-producing animals causes a steady rise of multiple antibiotic resistance in foodborne bacteria. Next to sulfonamides, the most common antibiotics groups are fluoroquinolones, aminoglycosides, and ß-lactams. Therefore, there is a need for a quick, efficient, and low-cost detection procedure for antibiotics. In this study, we propose an inkjet-printed aptamer-based biosensor developed for the detection of the fluoroquinolone ciprofloxacin. Due to their extraordinary high affinity and specificity, aptamers are already widely used in various applications. Here we present a ciprofloxacin-binding RNA aptamer developed by systematic evolution of ligands by exponential enrichment (SELEX). We characterized the secondary structure of the aptamer and determined the KD to 36 nM that allow detection of antibiotic contamination in a relevant range. We demonstrate that RNA aptamers can be inkjet-printed, dried, and resolved while keeping their functionality consistently intact. With this proof of concept, we are paving the way for a potential range of additional aptamer-based, printable biosensors.
      Citation: Biosensors
      PubDate: 2019-01-02
      DOI: 10.3390/bios9010007
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 8: Innovative Sensor Approach to Follow
           Campylobacter jejuni Development

    • Authors: Estefanía Núñez-Carmona, Marco Abbatangelo, Veronica Sberveglieri
      First page: 8
      Abstract: Campylobacter spp infection affects more than 200,000 people every year in Europe and in the last four years a trend shows an increase in campylobacteriosis. The main vehicle for transmission of the bacterium is contaminated food like meat, milk, fruit and vegetables. In this study, the aim was to find characteristic volatile organic compounds (VOCs) of C. jejuni in order to detect its presence with an array of metal oxide (MOX) gas sensors. Using a starting concentration of 103 CFU/mL, VOCs were analyzed using Gas-Chromatography Mass-Spectrometry (GC-MS) with a Solid-Phase Micro Extraction (SPME) technique at the initial time (T0) and after 20 h (T20). It has been found that a Campylobacter sample at T20 is characterized by a higher number of alcohol compounds that the one at T0 and this is due to sugar fermentation. Sensor results showed the ability of the system to follow bacteria curve growth from T0 to T20 using Principal Component Analysis (PCA). In particular, this results in a decrease of ΔR/R0 value over time. For this reason, MOX sensors are a promising technology for the development of a rapid and sensitive system for C. jejuni.
      Citation: Biosensors
      PubDate: 2019-01-07
      DOI: 10.3390/bios9010008
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 9: Energy Transfer between Tm-Doped Upconverting
           Nanoparticles and a Small Organic Dye with Large Stokes Shift

    • Authors: Anna López de Guereñu, Philipp Bastian, Pablo Wessig, Leonard John, Michael U. Kumke
      First page: 9
      Abstract: Lanthanide-doped upconverting nanoparticles (UCNP) are being extensively studied for bioapplications due to their unique photoluminescence properties and low toxicity. Interest in RET applications involving UCNP is also increasing, but due to factors such as large sizes, ion emission distributions within the particles, and complicated energy transfer processes within the UCNP, there are still many questions to be answered. In this study, four types of core and core-shell NaYF4-based UCNP co-doped with Yb3+ and Tm3+ as sensitizer and activator, respectively, were investigated as donors for the Methyl 5-(8-decanoylbenzo[1,2-d:4,5-d′]bis([1,3]dioxole)-4-yl)-5-oxopentanoate (DBD-6) dye. The possibility of resonance energy transfer (RET) between UCNP and the DBD-6 attached to their surface was demonstrated based on the comparison of luminescence intensities, band ratios, and decay kinetics. The architecture of UCNP influenced both the luminescence properties and the energy transfer to the dye: UCNP with an inert shell were the brightest, but their RET efficiency was the lowest (17%). Nanoparticles with Tm3+ only in the shell have revealed the highest RET efficiencies (up to 51%) despite the compromised luminescence due to surface quenching.
      Citation: Biosensors
      PubDate: 2019-01-08
      DOI: 10.3390/bios9010009
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 10: A Bioelectronic System to Measure the
           Glycolytic Metabolism of Activated CD4+ T Cells

    • Authors: Suzanne M. Crowe, Spyridon Kintzios, Grigoris Kaltsas, Clovis S. Palmer
      First page: 10
      Abstract: The evaluation of glucose metabolic activity in immune cells is becoming an increasingly standard task in immunological research. In this study, we described a sensitive, inexpensive, and non-radioactive assay for the direct and rapid measurement of the metabolic activity of CD4+ T cells in culture. A portable, custom-built Cell Culture Metabolite Biosensor device was designed to measure the levels of acidification (a proxy for glycolysis) in cell-free CD4+ T cell culture media. In this assay, ex vivo activated CD4+ T cells were incubated in culture medium and mini electrodes were placed inside the cell free culture filtrates in 96-well plates. Using this technique, the inhibitors of glycolysis were shown to suppress acidification of the cell culture media, a response similar to that observed using a gold standard lactate assay kit. Our findings show that this innovative biosensor technology has potential for applications in metabolic research, where acquisition of sufficient cellular material for ex vivo analyses presents a substantial challenge.
      Citation: Biosensors
      PubDate: 2019-01-09
      DOI: 10.3390/bios9010010
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 11: Acknowledgement to Reviewers of Biosensors
           in 2018

    • Authors: Biosensors Editorial Office
      First page: 11
      Abstract: Rigorous peer-review is the corner-stone of high-quality academic publishing [...]
      Citation: Biosensors
      PubDate: 2019-01-10
      DOI: 10.3390/bios9010011
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 12: Biochemical Changes in Irradiated Oral
           Mucosa: A FTIR Spectroscopic Study

    • Authors: Helena Ukkonen, Simo Vuokila, Jopi J. W. Mikkonen, Hannah Dekker, Engelbert A. J. M. Schulten, Elisabeth Bloemena, Arto Koistinen, Tulio A. Valdez, Arja M. Kullaa, Surya Pratap Singh
      First page: 12
      Abstract: Radiation exposure during the course of treatment in head and neck cancer (HNC) patients can induce both structural and biochemical anomalies. The present study is focused on utilizing infrared imaging for the identification of the minor biochemical alterations in the oral mucosa. Chemical maps generated using glycoprotein band indicates its differential distribution along the superficial layer. Spectra extracted from this layer suggests changes in overall nucleic acid and protein content in response to the therapeutic irradiation. Discrimination among control and irradiated groups have been achieved using principal component analysis. Findings of this preliminary study further support prospective utilization of Fourier Transform InfraRed (FTIR) imaging as a non-destructive, label-free tool for objective assessment of the oral mucosa in patient groups with or without radiation therapy.
      Citation: Biosensors
      PubDate: 2019-01-13
      DOI: 10.3390/bios9010012
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 13: Enzymatic Low Volume Passive Sweat Based
           Assays for Multi-Biomarker Detection

    • Authors: Ashlesha Bhide, Sarah Cheeran, Sriram Muthukumar, Shalini Prasad
      First page: 13
      Abstract: Simultaneous detection of correlated multi-biomarkers on a single low-cost platform in ultra-low fluid volumes with robustness is in growing demand for the development of wearable diagnostics. A non-faradaic biosensor for the simultaneous detection of alcohol, glucose, and lactate utilizing low volumes (1–5 μL) of sweat is demonstrated. Biosensing is implemented using nanotextured ZnO films integrated on a flexible porous membrane to achieve enhanced sensor performance. The ZnO sensing region is functionalized with enzymes specific for the detection of alcohol, glucose, and lactate in the ranges encompassing their physiologically relevant levels. A non-faradaic chronoamperometry technique is used to measure the current changes associated with interactions of the target biomarkers with their specific enzyme. The specificity performance of the biosensing platform was established in the presence of cortisol as the non-specific molecule. Biosensing performance of the platform in a continuous mode performed over a 1.5-h duration showed a stable current response to cumulative lifestyle biomarker concentrations with capability to distinguish reliably between low, mid, and high concentration ranges of alcohol (0.1, 25, 100 mg/dL), glucose (0.1, 10, 50 mg/dL), and lactate (1, 50, 100 mM). The low detection limits and a broader dynamic range for the lifestyle biomarker detection are quantified in this research demonstrating its suitability for translation into a wearable device.
      Citation: Biosensors
      PubDate: 2019-01-16
      DOI: 10.3390/bios9010013
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 14: Textile-Based Potentiometric Electrochemical
           pH Sensor for Wearable Applications

    • Authors: Libu Manjakkal, Wenting Dang, Nivasan Yogeswaran, Ravinder Dahiya
      First page: 14
      Abstract: In this work, we present a potentiometric pH sensor on textile substrate for wearable applications. The sensitive (thick film graphite composite) and reference electrodes (Ag/AgCl) are printed on cellulose-polyester blend cloth. An excellent adhesion between printed electrodes allow the textile-based sensor to be washed with a reliable pH response. The developed textile-based pH sensor works on the basis of electrochemical reaction, as observed through the potentiometric, cyclic voltammetry (100 mV/s) and electrochemical impedance spectroscopic (10 mHz to 1 MHz) analysis. The electrochemical double layer formation and the ionic exchanges of the sensitive electrode-pH solution interaction are observed through the electrochemical impedance spectroscopic analysis. Potentiometric analysis reveals that the fabricated textile-based sensor exhibits a sensitivity (slope factor) of 4 mV/pH with a response time of 5 s in the pH range 6–9. The presented sensor shows stable response with a potential of 47 ± 2 mV for long time (2000 s) even after it was washed in tap water. These results indicate that the sensor can be used for wearable applications.
      Citation: Biosensors
      PubDate: 2019-01-16
      DOI: 10.3390/bios9010014
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 15: Suppressing Non-Specific Binding of Proteins
           onto Electrode Surfaces in the Development of Electrochemical

    • Authors: Jesús E. Contreras-Naranjo, Oscar Aguilar
      First page: 15
      Abstract: Electrochemical immunosensors, EIs, are systems that combine the analytical power of electrochemical techniques and the high selectivity and specificity of antibodies in a solid phase immunoassay for target analyte. In EIs, the most used transducer platforms are screen printed electrodes, SPEs. Some characteristics of EIs are their low cost, portability for point of care testing (POCT) applications, high specificity and selectivity to the target molecule, low sample and reagent consumption and easy to use. Despite all these attractive features, still exist one to cover and it is the enhancement of the sensitivity of the EIs. In this review, an approach to understand how this can be achieved is presented. First, it is necessary to comprise thoroughly all the complex phenomena that happen simultaneously in the protein-surface interface when adsorption of the protein occurs. Physicochemical properties of the protein and the surface as well as the adsorption phenomena influence the sensitivity of the EIs. From this point, some strategies to suppress non-specific binding, NSB, of proteins onto electrode surfaces in order to improve the sensitivity of EIs are mentioned.
      Citation: Biosensors
      PubDate: 2019-01-18
      DOI: 10.3390/bios9010015
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 16: Ultrathin Functional Polymer Modified
           Graphene for Enhanced Enzymatic Electrochemical Sensing

    • Authors: Anitha Devadoss, Rhiannan Forsyth, Ryan Bigham, Hina Abbasi, Muhammad Ali, Zari Tehrani, Yufei Liu, Owen. J. Guy
      First page: 16
      Abstract: Grafting thin polymer layers on graphene enables coupling target biomolecules to graphene surfaces, especially through amide and aldehyde linkages with carboxylic acid and primary amine derivatives, respectively. However, functionalizing monolayer graphene with thin polymer layers without affecting their exceptional electrical properties remains challenging. Herein, we demonstrate the controlled modification of chemical vapor deposition (CVD) grown single layer graphene with ultrathin polymer 1,5-diaminonaphthalene (DAN) layers using the electropolymerization technique. It is observed that the controlled electropolymerization of DAN monomer offers continuous polymer layers with thickness ranging between 5–25 nm. The surface characteristics of pure and polymer modified graphene was examined. As anticipated, the number of surface amine groups increases with increases in the layer thickness. The effects of polymer thickness on the electron transfer rates were studied in detail and a simple route for the estimation of surface coverage of amine groups was demonstrated using the electrochemical analysis. The implications of grafting ultrathin polymer layers on graphene towards horseradish peroxidase (HRP) enzyme immobilization and enzymatic electrochemical sensing of H2O2 were discussed elaborately.
      Citation: Biosensors
      PubDate: 2019-01-18
      DOI: 10.3390/bios9010016
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 17: A Novel Wearable Device for Continuous
           Ambulatory ECG Recording: Proof of Concept and Assessment of Signal

    • Authors: Christian Steinberg, François Philippon, Marina Sanchez, Pascal Fortier-Poisson, Gilles O’Hara, Franck Molin, Jean-François Sarrazin, Isabelle Nault, Louis Blier, Karine Roy, Benoit Plourde, Jean Champagne
      First page: 17
      Abstract: Diagnosis of arrhythmic disorders is challenging because of their short-lasting, intermittent character. Conventional technologies of noninvasive ambulatory rhythm monitoring are limited by modest sensitivity. We present a novel form of wearable electrocardiogram (ECG) sensors providing an alternative tool for long-term rhythm monitoring with the potential of increased sensitivity to detect intermittent or subclinical arrhythmia. The objective was to assess the signal quality and R-R coverage of a wearable ECG sensor system compared to a standard 3-lead Holter. In this phase-1 trial, healthy individuals underwent 24-h simultaneous rhythm monitoring using the OMsignal system together with a 3-lead Holter recording. The OMsignal system consists of a garment (bra or shirt) with integrated sensors recording a single-lead ECG and an acquisition module for data storage and processing. Head-to-head signal quality was assessed regarding adequate P-QRS-T distinction and was performed by three electrophysiologists blinded to the recording technology. The accuracy of signal coverage was assessed using Bland-Altman analysis. Fifteen individuals underwent simultaneous 24-h recording. Signal quality and accuracy of the OMgaments was equivalent to Holter-monitoring (84% vs 93% electrophysiologists rating, p = 0.06). Signal coverage of R-R intervals showed a very close overlay between the OMsignal system and Holter signals, mean difference in heart rate of 2 5 bpm. The noise level of OMgarments was comparable to Holter recording. OMgarments provide high signal quality for adequate rhythm analysis, representing a promising novel technology for long-term non-invasive ECG monitoring.
      Citation: Biosensors
      PubDate: 2019-01-21
      DOI: 10.3390/bios9010017
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 18: A Molecular Interaction Analysis Reveals the
           Possible Roles of Graphene Oxide in a Glucose Biosensor

    • Authors: Tony Sumaryada, Muhammad Sandy Gunawan, Salahuddin Perdana, Sugianto Arjo, Akhiruddin Maddu
      First page: 18
      Abstract: In this paper, we report the molecular docking study of graphene oxide and glucose oxidase (GOx) enzyme for a potential glucose biosensing application. The large surface area and good electrical properties have made graphene oxide as one of the best candidates for an enzyme immobilizer and transducer in the biosensing system. Our molecular docking results revealed that graphene oxide plays a role as a GOx enzyme immobilizer in the glucose biosensor system since it can spontaneously bind with GOx at specific regions separated from the active sites of glucose and not interfering or blocking the glucose sensing by GOx in an enzyme-assisted biosensor system. The strongest binding affinity of GOx-graphene oxide interaction is −11.6 kCal/mol and dominated by hydrophobic interaction. Other modes of interactions with a lower binding affinity have shown the existence of some hydrogen bonds (H-bonds). A possibility of direct sensing (interaction) model of glucose by graphene oxide (non-enzymatic sensing mechanism) was also studied in this paper, and showed a possible direct glucose sensing by graphene oxide through the H-bond interaction, even though with a much lower binding affinity of −4.2 kCal/mol. It was also found that in a direct glucose sensing mechanism, the sensing interaction can take place anywhere on the graphene oxide surface with almost similar binding affinity.
      Citation: Biosensors
      PubDate: 2019-01-28
      DOI: 10.3390/bios9010018
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 19: Integrated Microfluidic Devices Fabricated
           in Poly (Methyl Methacrylate) (PMMA) for On-site Therapeutic Drug
           Monitoring of Aminoglycosides in Whole Blood

    • Authors: Zaidon T. Al-aqbi, Yiing C. Yap, Feng Li, Michael C. Breadmore
      First page: 19
      Abstract: On-site therapeutic drug monitoring (TDM) is important for providing a quick and accurate dosing to patients in order to improve efficacy and minimize toxicity. Aminoglycosides such as amikacin, gentamicin, and tobramycin are important antibiotics that have been commonly used to treat infections of chronic bacterial infections in the urinary tract, lung, and heart. However, these aminoglycosides can lead to vestibular and auditory dysfunction. Therefore, TDM of aminoglycosides is important due to their ototoxicity and nephrotoxicity. Here, we have developed a hot embossed poly (methyl methacrylate) (PMMA) microfluidic device featuring an electrokinetic size and mobility trap (SMT) to purify, concentrate, and separate the aminoglycoside antibiotic drugs amikacin, gentamicin, and tobramycin. These drugs were separated successfully from whole blood within 3 min, with 30-fold lower detection limits compared to a standard pinched injection. The limit of detections (LOD) were 3.75 µg/mL for gentamicin, 8.53 µg/mL for amikacin, and 6.00 µg/mL for tobramycin. These are sufficient to cover the therapeutic range for treating sepsis of 6–10 μg/mL gentamicin and tobramycin and 12–20 μg/mL of amikacin. The device is simple and could be mass produced via embossing or injection molding approaches.
      Citation: Biosensors
      PubDate: 2019-01-30
      DOI: 10.3390/bios9010019
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 20: Trends and Perspectives in Immunosensors for
           Determination of Currently-Used Pesticides: The Case of Glyphosate,
           Organophosphates, and Neonicotinoids

    • Authors: Eduardo C. Reynoso, Eduardo Torres, Francesca Bettazzi, Ilaria Palchetti
      First page: 20
      Abstract: Pesticides, due to their intensive use and their peculiar chemical features, can persist in the environment and enter the trophic chain, thus representing an environmental risk for the ecosystems and human health. Although there are several robust and reliable standard analytical techniques for their monitoring, the high frequency of contamination caused by pesticides requires methods for massive monitoring campaigns that are capable of rapidly detecting these compounds in many samples of different origin. Immunosensors represent a potential tool for simple, rapid, and sensitive monitoring of pesticides. Antibodies coupled to electrochemical or optical transducers have resulted in effective detection devices. In this review, the new trends in immunosensor development and the application of immunosensors for the detection of pesticides of environmental concern—such as glyphosate, organophosphates, and neonicotinoids—are described.
      Citation: Biosensors
      PubDate: 2019-02-04
      DOI: 10.3390/bios9010020
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 21: Development of Tin Oxide-Based Nanosensors
           for Electronic Nose Environmental Applications

    • Authors: Sayago, Aleixandre, Santos
      First page: 21
      Abstract: Tin oxide nanofibres (NFs) are used as nanosensors in electronic noses. Their performance is compared to that of oxide commercial chemical sensors for pollutant detection. NFs were grown by electrospinning and deposited onto silicon substrates with integrated micro-hotplates. NF morphology was characterized by scanning electron microscopy (SEM). The NFs presented high sensitivity to NO2 at low temperature.
      Citation: Biosensors
      PubDate: 2019-02-05
      DOI: 10.3390/bios9010021
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 22: SAM Composition and Electrode Roughness
           Affect Performance of a DNA Biosensor for Antibiotic Resistance

    • Authors: Butterworth, Blues, Williamson, Cardona, Gray, Corrigan
      First page: 22
      Abstract: Antibiotic resistance is a growing concern in the treatment of infectious disease worldwide. Point-of-care (PoC) assays which rapidly identify antibiotic resistance in a sample will allow for immediate targeted therapy which improves patient outcomes and helps maintain the effectiveness of current antibiotic stockpiles. Electrochemical assays offer many benefits, but translation from a benchtop measurement system to low-cost portable electrodes can be challenging. Using electrochemical and physical techniques, this study examines how different electrode surfaces and bio-recognition elements, i.e. the self-assembled monolayer (SAM), affect the performance of a biosensor measuring the hybridisation of a probe for antibiotic resistance to a target gene sequence in solution. We evaluate several commercially available electrodes which could be suitable for PoC testing with different SAM layers and show that electrode selection also plays an important role in overall biosensor performance.
      Citation: Biosensors
      PubDate: 2019-02-07
      DOI: 10.3390/bios9010022
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 23: Fast identification of Bacteria for Quality
           Control of Drinking Water through A Static Headspace Sampler Coupled to a
           Sensory Perception System

    • Authors: Carrillo, Durán
      First page: 23
      Abstract: The aim of this study was to develop and implement a methodology composed by a Static Head-Space-Sampler (SHS) coupled to a Sensory Perception System (SPS) for the extraction of Volatile Organic Compounds (VOC’s) emitted by bacterial species in the water. The SPS was performed by means of a chamber of 16 Metal-Oxide-Semiconductor (MOS) gas sensors and a software with pattern recognition methods for the detection and identification of bacteria. At first, the tests were conducted from the sterile and polluted water with the Escherichia coli bacteria and modifying the incubation temperatures (50 °C, 70 °C and 90 °C), with the objective to obtain an optimal temperature for the distinguishing of species. Furthermore, the capacity of the methodology to distinguish the important compounds was assessed, in this case, E. coli and other bacteria like Pseudomonas aeruginosa and Klebsiella oxytoca, which formed similar analytes. The validation of the proposed methodology was done by acquiring water samples from different unitary operations of an aqueduct of the municipality of Toledo (North of Santander, Colombia), which were analyzed by the membrane filter technique in the laboratories of the University of Pamplona, along with the SHS-SPS system. The results showed that it was possible to distinguish polluted water samples in a fast way through the sensory measurement equipment using pattern recognition techniques such as Principal Component Analysis (PCA), Discriminant Function Analysis (DFA) and a probabilistic neural network (PNN), where a 95% of differentiation was obtained through PCA and 100% of the classification with DFA. The PNN network achieved the 86.6% of success rate with the cross-validation technique “leave one out”.
      Citation: Biosensors
      PubDate: 2019-02-08
      DOI: 10.3390/bios9010023
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 24: Rapid Drop-Test for Lectin Binding with
           Glycopolymer-Coated Optical Ring Resonators

    • Authors: Schulte-Osseili, Kleinert, Keil, Rosencrantz
      First page: 24
      Abstract: We fabricated a simple sensor system for qualitative analysis of glycan-mediated interactions. Our main aim was to establish a ronbbust system that allowes drop-tests without complex fluidics. The test system should be usable in routine analytics in the future and bear sufficient sensitivity to detect binding events in the nanomolar range. For this, we employed optical ring resonators and coated them with high avidity glycopolymers based on N-acetylglucosamine (GlcNAc). These hydrophilic polymers are also very feasible in preventing unspecific protein adsorption. Drop-on binding studies with suitable lectins showed that glycopolymers were specifically recognized by a lectin with GlcNAc-specificity and prevented unspecific protein interactions very well. The system could be elaborated in the future for detection of glycan-mediated interactions in the biomedical field and is promising in means of multiplexed analysis and usage in routine analysis.
      Citation: Biosensors
      PubDate: 2019-02-12
      DOI: 10.3390/bios9010024
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 25: The Recent Advances in Raman Microscopy and
           Imaging Techniques for Biosensors

    • Authors: Rzhevskii
      First page: 25
      Abstract: Raman microspectroscopy is now well established as one of the most powerful analytical techniques for a diverse range of applications in physical (material) and biological sciences. Consequently, the technique provides exceptional analytical opportunities to the science and technology of biosensing due to its capability to analyze both parts of a biosensor system—biologically sensitive components, and a variety of materials and systems used in physicochemical transducers. Recent technological developments in Raman spectral imaging have brought additional possibilities in two- and three-dimensional (2D and 3D) characterization of the biosensor’s constituents and their changes on a submicrometer scale in a label-free, real-time nondestructive method of detection. In this report, the essential components and features of a modern confocal Raman microscope are reviewed using the instance of Thermo Scientific DXRxi Raman imaging microscope, and examples of the potential applications of Raman microscopy and imaging for constituents of biosensors are presented.
      Citation: Biosensors
      PubDate: 2019-02-12
      DOI: 10.3390/bios9010025
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 26: Response Surface Methodology for the
           Optimisation of Electrochemical Biosensors for Heavy Metals Detection

    • Authors: Giuseppe Egidio De Benedetto, Sabrina Di Masi, Antonio Pennetta, Cosimino Malitesta
      First page: 26
      Abstract: Herein, we report the application of a chemometric tool for the optimisation of electrochemical biosensor performances. The experimental design was performed based on the responses of an amperometric biosensor developed for metal ions detection using the flow injection analysis. The electrode preparation and the working conditions were selected as experimental parameters, and thus, were modelled by a response surface methodology (RSM). In particular, enzyme concentration, flow rates, and number of cycles were reported as continuous factors, while the sensitivities of the biosensor (S, µA·mM−1) towards metals, such as Bi3+ and Al3+ were collected as responses and optimised by a central composite design (CCD). Bi3+ and Al3+ inhibition on the Pt/PPD/GOx biosensor response is for the first time reported. The optimal enzyme concentration, scan cycles and flow rate were found to be 50 U·mL−1, 30 and, 0.3 mL·min−1, respectively. Descriptive/predictive performances are discussed: the sensitivities of the optimised biosensor agreed with the experimental design prediction. The responses under the optimised conditions were also tested towards Ni2+ and Ag+ ions. The multivariate approach used in this work allowed us to obtain a wide working range for the biosensor, coupled with a high reproducibility of the response (RSD = 0.72%).
      Citation: Biosensors
      PubDate: 2019-02-13
      DOI: 10.3390/bios9010026
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 27: Saliva, a Magic Biofluid Available for
           Multilevel Assessment and a Mirror of General Health—A Systematic Review

    • Authors: Aranka Ilea, Vlad Andrei, Claudia Nicoleta Feurdean, Anida-Maria Băbțan, Nausica Bianca Petrescu, Radu Septimiu Câmpian, Adina Bianca Boșca, Bianca Ciui, Mihaela Tertiș, Robert Săndulescu, Cecilia Cristea
      First page: 27
      Abstract: Background: Saliva has been recently proposed as an alternative to classic biofluid analyses due to both availability and reliability regarding the evaluation of various biomarkers. Biosensors have been designed for the assessment of a wide spectrum of compounds, aiding in the screening, diagnosis, and monitoring of pathologies and treatment efficiency. This literature review aims to present the development in the biosensors research and their utility using salivary assessment. Methods: a comprehensive literature search has been conducted in the PubMed database, using the keywords “saliva” and “sensor”. A two-step paper selection algorithm was devised and applied. Results: The 49 papers selected for the present review focused on assessing the salivary biomarkers used in general diseases, oral pathologies, and pharmacology. The biosensors proved to be reliable tools for measuring the salivary levels of biochemical metabolic compounds such as glucose, proteinases and proteins, heavy metals and various chemical compounds, microorganisms, oncology markers, drugs, and neurotransmitters. Conclusions: Saliva is a biofluid with a significant clinical applicability for the evaluation and monitoring of a patient’s general health. Biosensors designed for assessing a wide range of salivary biomarkers are emerging as promising diagnostic or screening tools for improving the patients’ quality of life.
      Citation: Biosensors
      PubDate: 2019-02-14
      DOI: 10.3390/bios9010027
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 28: Toward Highly Efficient Cancer Imaging and
           Therapy Using the Environment-Friendly Chitosan Nanoparticles and NIR

    • Authors: Hala S. Abuelmakarem, Mahmoud A. Sliem, Jala El-Azab, Moustafa M. A. Farghaly, Wafaa A. Ahmed
      First page: 28
      Abstract: Chitosan-tripolyphosphate nanoparticles (C-TPP NPs) were synthesized to investigate their cytotoxicity against colon cancer cells (Caco2 cells) in the absence and the presence of a near-infrared (NIR) laser to evaluate their influence in cancer detection using the NIR laser and to evaluate the NIR laser on cancer treatment. The synthesized NPs were characterized by Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), zeta potential (ZP), and transmission electronic microscope (TEM). The cytotoxicity was analyzed by the MTT test and the cell viability was assessed using the Trypan blue method. C-TPP NPs showed increased cytotoxicity and decreased cell viability against Caco2 cells. Upon laser exposure only, the cell viability decreased. The C-TPP NPs appeared to have a shining light on the cancerous cells which were photographed under the inverted microscope.
      Citation: Biosensors
      PubDate: 2019-02-18
      DOI: 10.3390/bios9010028
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 29: Differentiation of Patients with Balance
           Insufficiency (Vestibular Hypofunction) versus Normal Subjects Using a
           Low-Cost Small Wireless Wearable Gait Sensor

    • Authors: Tam Q. Nguyen, Jonathan H. Young, Amanda Rodriguez, Steven Zupancic, Donald Y.C. Lie
      First page: 29
      Abstract: Balance disorders present a significant healthcare burden due to the potential for hospitalization or complications for the patient, especially among the elderly population when considering intangible losses such as quality of life, morbidities, and mortalities. This work is a continuation of our earlier works where we now examine feature extraction methodology on Dynamic Gait Index (DGI) tests and machine learning classifiers to differentiate patients with balance problems versus normal subjects on an expanded cohort of 60 patients. All data was obtained using our custom designed low-cost wireless gait analysis sensor (WGAS) containing a basic inertial measurement unit (IMU) worn by each subject during the DGI tests. The raw gait data is wirelessly transmitted from the WGAS for real-time gait data collection and analysis. Here we demonstrate predictive classifiers that achieve high accuracy, sensitivity, and specificity in distinguishing abnormal from normal gaits. These results show that gait data collected from our very low-cost wearable wireless gait sensor can effectively differentiate patients with balance disorders from normal subjects in real-time using various classifiers. Our ultimate goal is to be able to use a remote sensor such as the WGAS to accurately stratify an individual’s risk for falls.
      Citation: Biosensors
      PubDate: 2019-02-26
      DOI: 10.3390/bios9010029
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 30: Dielectrophoresis Manipulation: Versatile
           Lateral and Vertical Mechanisms

    • Authors: Muhamad Ramdzan Buyong, Aminuddin Ahmad Kayani, Azrul Azlan Hamzah, Burhanuddin Yeop Majlis
      First page: 30
      Abstract: Discussing the topic of the capability of dielectrophoresis (DEP) devices in terms of the selective detection and rapid manipulation of particles based on the DEP force (FDEP) via contactless methods is challenging in medical research, drug discovery and delivery. Nonetheless, the process of the selective detection and rapid manipulation of particles via contactless DEP based on dielectric particles and the surrounding medium can reduce the effects of major issues, including physical contact with the particles and medium contamination to overcome operational difficulties. In this review, DEP microelectromechanical system (MEMS) microelectrodes with a tapered profile for the selective detection and rapid manipulation of particles were studied and compared with those of conventional designs with a straight-cut profile. The main objective of this manuscript is to review the versatile mechanism of tapered DEP MEMS microelectrodes for the purpose of selective detection and rapid manipulation. Thus, this review provides a versatile filtration mechanism with the potential for a glomerular-based membrane in an artificial kidneys’ development solution for implementing engineered particles and cells by lateral attraction as well as vertical repulsion in the development of lab-on-a-chip applications. For tapered DEP MEMS microelectrodes, the scope of this study methodology involved the characterisation of DEP, modelling of the polarisation factor and the dynamic dielectric changes between the particles and medium. Comprehensive discussions are presented on the capability of tapered DEP microelectrodes to drive the selected particles and the simulation, fabrication and testing of the tapered profile. This study revealed an outstanding performance with the capability of producing two regions of high electric field intensity at the bottom and top edges of the side wall of tapered microelectrodes. Observations on particle separation mainly by the lateral attraction force of particles with positive DEP on the y-axis and vertical repulsion force of particles with negative DEP on the z-axis proved an efficient and uniform FDEP produced by tapered electrodes. In conclusion, this study confirmed the reliability and efficiency of the tapered DEP microelectrodes in the process of selective detection and rapid manipulation at a higher efficiency rate than straight-cut microelectrodes, which is significant in DEP technology applications.
      Citation: Biosensors
      PubDate: 2019-02-26
      DOI: 10.3390/bios9010030
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 31: Electrochemical Sensor Based on Molecularly
           Imprinted Polymer for the Detection of Cefalexin

    • Authors: Bogdan Feier, Adrian Blidar, Alexandra Pusta, Paula Carciuc, Cecilia Cristea
      First page: 31
      Abstract: In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.
      Citation: Biosensors
      PubDate: 2019-02-27
      DOI: 10.3390/bios9010031
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 32: Plasma from Patients with Rheumatoid
           Arthritis Reduces Nitric Oxide Synthesis and Induces Reactive Oxygen
           Species in A Cell-Based Biosensor

    • Authors: Herbert Herlitz-Cifuentes, Camila Vejar, Alejandra Flores, Paola Jara, Paulina Bustos, Irene Castro, Evelyn Poblete, Katia Saez, Marina Opazo, Jorge Gajardo, Claudio Aguayo, Estefania Nova-Lamperti, Liliana Lamperti
      First page: 32
      Abstract: Rheumatoid arthritis (RA) has been associated with a higher risk of developing cardiovascular (CV) diseases. It has been proposed that systemic inflammation plays a key role in premature atherosclerosis development, and is therefore crucial to determine whether systemic components from RA patients promotes endothelial cell-oxidative stress by affecting reactive oxygen species (ROS) and nitric-oxide (NO) production. The aim of this study was to evaluate whether plasma from RA patients impair NO synthesis and ROS production by using the cell-line ECV-304 as a biosensor. NO synthesis and ROS production were measured in cells incubated with plasma from 73 RA patients and 52 healthy volunteers by fluorimetry. In addition, traditional CV risk factors, inflammatory molecules and disease activity parameters were measured. Cells incubated with plasma from RA patients exhibited reduced NO synthesis and increased ROS production compared to healthy volunteers. Furthermore, the imbalance between NO synthesis and ROS generation in RA patients was not associated with traditional CV risk factors. Our data suggest that ECV-304 cells can be used as a biosensor of systemic inflammation-induced endothelial cell-oxidative stress. We propose that both NO and ROS production are potential biomarkers aimed at improving the current assessment of CV risk in RA.
      Citation: Biosensors
      PubDate: 2019-02-27
      DOI: 10.3390/bios9010032
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 33: In-Vitro Characterization of
           mCerulean3_mRuby3 as a Novel FRET Pair with Favorable Bleed-Through

    • Authors: Kira Erismann-Ebner, Anne Marowsky, Michael Arand
      First page: 33
      Abstract: In previous studies, we encountered substantial problems using the CFP_YFP Förster resonance energy transfer (FRET) pair to analyze protein proximity in the endoplasmic reticulum of live cells. Bleed-through of the donor emission into the FRET channel and overlap of the FRET emission wavelength with highly variable cellular autofluorescence significantly compromised the sensitivity of our analyses. Here, we propose mCerulean3 and mRuby3 as a new FRET pair to potentially overcome these problems. Fusion of the two partners with a trypsin-cleavable linker allowed the direct comparison of the FRET signal characteristics of the associated partners with those of the completely dissociated partners. We compared our new FRET pair with the canonical CFP_YFP and the more recent mClover3_mRuby3 pairs and found that, despite a lower total FRET signal intensity, the novel pair had a significantly better signal to noise ratio due to lower donor emission bleed-through. This and the fact that the mRuby3 emission spectrum did not overlap with that of common cellular autofluorescence renders the mCerulean3_mRuby3 FRET pair a promising alternative to the common CFP_YFP FRET pair for the interaction analysis of membrane proteins in living cells.
      Citation: Biosensors
      PubDate: 2019-02-28
      DOI: 10.3390/bios9010033
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 34: Surface Enhanced Raman Spectroscopy of
           Lactoferrin Adsorbed on Silvered Porous Silicon Covered with Graphene

    • Authors: Sergey Zavatski, Nadia Khinevich, Kseniya Girel, Sergey Redko, Nikolai Kovalchuk, Ivan Komissarov, Vladimir Lukashevich, Igor Semak, Kahramon Mamatkulov, Maria Vorobyeva, Grigory Arzumanyan, Hanna Bandarenka
      First page: 34
      Abstract: We registered surface enhanced Raman scattering (SERS) spectra of the human lactoferrin molecules adsorbed on a silvered porous silicon (por-Si) from 10−6–10−18 M solutions. It was found that the por-Si template causes a negative surface potential of silver particles and their chemical resistivity to oxidation. These properties provided to attract positively charged lactoferrin molecules and prevent their interaction with metallic particles upon 473 nm laser excitation. The SERS spectra of lactoferrin adsorbed from 10−6 M solution were rather weak but a decrease of the concentration to 10−10 M led to an enormous growth of the SERS signal. This effect took place as oligomers of lactoferrin were broken down to monomeric units while its concentration was reduced. Oligomers are too large for a uniform overlap with electromagnetic field from silver particles. They cannot provide an intensive SERS signal from the top part of the molecules in contrast to monomers that can be completely covered by the electromagnetic field. The SERS spectra of lactoferrin at the 10−14 and 10−16 M concentrations were less intensive and started to change due to increasing contribution from the laser burned molecules. To prevent overheating the analyte molecules on the silvered por-Si were protected with graphene, which allowed the detection of lactoferrin adsorbed from the 10−18 M solution.
      Citation: Biosensors
      PubDate: 2019-02-28
      DOI: 10.3390/bios9010034
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 35: Use of Electronic Noses for Diagnosis of
           Digestive and Respiratory Diseases through the Breath

    • Authors: Carlos Sánchez, J. Pedro Santos, Jesús Lozano
      First page: 35
      Abstract: The increased occurrence of chronic diseases related to lifestyle or environmental conditions may have a detrimental effect on long-term health if not diagnosed and controlled in time. For this reason, it is important to develop new noninvasive early diagnosis equipment that allows improvement of the current diagnostic methods. This, in turn, has led to an exponential development of technology applied to the medical sector, such as the electronic nose. In addition, the appearance of this type of technology has allowed the possibility of studying diseases from another point of view, such as through breath analysis. This paper presents a bibliographic review of past and recent studies, selecting those investigations in which a patient population was studied with electronic nose technology, in order to identify potential applications of this technology in the detection of respiratory and digestive diseases through the analysis of volatile organic compounds present in the breath.
      Citation: Biosensors
      PubDate: 2019-02-28
      DOI: 10.3390/bios9010035
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 36: Solid-State rGO-PEDOT:PSS Transducing
           Material for Cost-Effective Enzymatic Sensing

    • Authors: Firdaus Abd-Wahab, Habibah Farhana Abdul Guthoos, Wan Wardatul Amani Wan Salim
      First page: 36
      Abstract: Performance of a sensing device is dependent on its construction material, especially for components that are directly involved in transporting and translating signals across the device. Understanding the morphology and characteristics of the material components is therefore crucial in the development of any sensing device. This work examines the morphological and electrochemical characteristics of reduced graphene oxide interspersed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (rGO-PEDOT:PSS) used as a transducer material deposited on a commercially available screen-printed carbon electrode (SPCE). Electron microscopy shows that PEDOT:PSS is interspersed between rGO layers. Raman and XRD analyses suggest that the graphene crystallinity in GO-PEDOT:PSS and rGO-PEDOT:PSS remains intact. Instead, PEDOT:PSS undergoes a change in structure to allow PEDOT to blend into the graphene structure and partake in the π-π interaction with the surface of the rGO layers. Incorporation of PEDOT:PSS also appears to improve the electrochemical behavior of the composite, leading to a higher peak current of 1.184 mA, as measured by cyclic voltammetry, compared to 0.522 mA when rGO is used alone. The rGO-PEDOT:PSS transducing material blended with glucose oxidase was tested for glucose detection. The sensitivity of glucose detection was shown to be 57.3 µA/(mM·cm2) with a detection limit of 86.8 µM.
      Citation: Biosensors
      PubDate: 2019-03-01
      DOI: 10.3390/bios9010036
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 37: Waveguiding and SERS Simplified Raman
           Spectroscopy on Biological Samples

    • Authors: Immanuel Valpapuram, Patrizio Candeloro, Maria Laura Coluccio, Elvira Immacolata Parrotta, Andrea Giugni, Gobind Das, Gianni Cuda, Enzo Di Fabrizio, Gerardo Perozziello
      First page: 37
      Abstract: Biomarkers detection at an ultra-low concentration in biofluids (blood, serum, saliva, etc.) is a key point for the early diagnosis success and the development of personalized therapies. However, it remains a challenge due to limiting factors like (i) the complexity of analyzed media, and (ii) the aspecificity detection and the poor sensitivity of the conventional methods. In addition, several applications require the integration of the primary sensors with other devices (microfluidic devices, capillaries, flasks, vials, etc.) where transducing the signal might be difficult, reducing performances and applicability. In the present work, we demonstrate a new class of optical biosensor we have developed integrating an optical waveguide (OWG) with specific plasmonic surfaces. Exploiting the plasmonic resonance, the devices give consistent results in surface enhanced Raman spectroscopy (SERS) for continuous and label-free detection of biological compounds. The OWG allows driving optical signals in the proximity of SERS surfaces (detection area) overcoming spatial constraints, in order to reach places previously optically inaccessible. A rutile prism couples the remote laser source to the OWG, while a Raman spectrometer collects the SERS far field scattering. The present biosensors were implemented by a simple fabrication process, which includes photolithography and nanofabrication. By using such devices, it was possible to detect cell metabolites like Phenylalanine (Phe), Adenosine 5-triphosphate sodium hydrate (ATP), Sodium Lactate, Human Interleukin 6 (IL6), and relate them to possible metabolic pathway variation.
      Citation: Biosensors
      PubDate: 2019-03-03
      DOI: 10.3390/bios9010037
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 38: Electrochemical Biosensors as Potential
           Diagnostic Devices for Autoimmune Diseases

    • Authors: Anca Florea, Gheorghe Melinte, Ioan Simon, Cecilia Cristea
      First page: 38
      Abstract: An important class of biosensors is immunosensors, affinity biosensors that are based on the specific interaction between antibodies and antigens. They are classified in four classes based on the type of employed transducer: electrochemical, optical, microgravimetric, and thermometric and depending on the type of recognition elements, antibodies, aptamers, microRNAs and recently peptides are integrating parts. Those analytical devices are able to detect peptides, antibodies and proteins in various sample matrices, without many steps of sample pretreatment. Their high sensitivity, low cost and the easy integration in point of care devices assuring portability are attracting features that justify the increasing interest in their development. The use of nanomaterials, simultaneous multianalyte detection and integration on platforms to form point-of-care devices are promising tools that can be used in clinical analysis for early diagnosis and therapy monitoring in several pathologies. Taking into account the growing incidence of autoimmune disease and the importance of early diagnosis, electrochemical biosensors could represent a viable alternative to currently used diagnosis methods. Some relevant examples of electrochemical assays for autoimmune disease diagnosis developed in the last several years based on antigens, antibodies and peptides as receptors were gathered and will be discussed further.
      Citation: Biosensors
      PubDate: 2019-03-04
      DOI: 10.3390/bios9010038
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 39: An Exfoliated Graphite-Based Electrochemical
           Immunosensor on a Dendrimer/Carbon Nanodot Platform for the Detection of
           Carcinoembryonic Antigen Cancer Biomarker

    • Authors: Azeez O. Idris, Nonhlangabezo Mabuba, Omotayo A. Arotiba
      First page: 39
      Abstract: An electrochemical immunosensor for the quantification of carcinoembryonic antigen (CEA) using a nanocomposite of polypropylene imine dendrimer (PPI) and carbon nanodots (CNDTs) on an exfoliated graphite electrode (EG) is reported. The carbon nanodots were prepared by pyrolysis of oats. The nanocomposites (PPI and CNDTs) were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The proposed immunosensor was prepared on an exfoliated graphite electrode sequentially by drop coating CNDTs, the electrodeposition of G2-PPI (generation 2 poly (propylene imine) dendrimer), the immobilization of anti-CEA on the modified electrode for 80 min at 35 °C, and dropping of bovine serum albumin (BSA) to minimize non-specific binding sites. Cyclic voltammetry was used to characterize each stage of the fabrication of the immunosensor. The proposed immunosensor detected CEA within a concentration range of 0.005 to 300 ng/mL with a detection limit of 0.00145 ng/mL by using differential pulse voltammetry (DPV). The immunosensor displayed good stability and was also selective in the presence of some interference species such as ascorbic acid, glucose, alpha-fetoprotein, prostate-specific antigen and human immunoglobulin. Furthermore, the fabricated immunosensor was applied in the quantification of CEA in a human serum sample, indicating its potential for real sample analysis.
      Citation: Biosensors
      PubDate: 2019-03-08
      DOI: 10.3390/bios9010039
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 40: Separation and Detection of Escherichia coli
           and Saccharomyces cerevisiae Using a Microfluidic Device Integrated with
           an Optical Fibre

    • Authors: Mohd Firdaus Kamuri, Zurina Zainal Abidin, Mohd Hanif Yaacob, Mohd Nizar Hamidon, Nurul Amziah Md Yunus, Suryani Kamarudin
      First page: 40
      Abstract: This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.
      Citation: Biosensors
      PubDate: 2019-03-14
      DOI: 10.3390/bios9010040
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 41: Enzyme-Based Electrochemical Biosensors for
           Microfluidic Platforms to Detect Pharmaceutical Residues in Wastewater

    • Authors: Ana Lucia Campaña, Sergio Leonardo Florez, Mabel Juliana Noguera, Olga P. Fuentes, Paola Ruiz Puentes, Juan C. Cruz, Johann F. Osma
      First page: 41
      Abstract: Emerging water pollutants such as pharmaceutical contaminants are suspected to induce adverse effects to human health. These molecules became worrisome due to their increasingly high concentrations in surface waters. Despite this alarming situation, available data about actual concentrations in the environment is rather scarce, as it is not commonly monitored or regulated. This is aggravated even further by the absence of portable and reliable methods for their determination in the field. A promising way to tackle these issues is the use of enzyme-based and miniaturized biosensors for their electrochemical detection. Here, we present an overview of the latest developments in amperometric microfluidic biosensors that include, modeling and multiphysics simulation, design, manufacture, testing, and operation methods. Different types of biosensors are described, highlighting those based on oxidases/peroxidases and the integration with microfluidic platforms. Finally, issues regarding the stability of the biosensors and the enzyme molecules are discussed, as well as the most relevant approaches to address these obstacles.
      Citation: Biosensors
      PubDate: 2019-03-15
      DOI: 10.3390/bios9010041
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 42: Integration of Nanomaterials and
           Bioluminescence Resonance Energy Transfer Techniques for Sensing

    • Authors: Hwang, Song, Zhang
      First page: 42
      Abstract: Bioluminescence resonance energy transfer (BRET) techniques offer a high degree of sensitivity, reliability and ease of use for their application to sensing biomolecules. BRET is a distance dependent, non-radiative energy transfer, which uses a bioluminescent protein to excite an acceptor through the resonance energy transfer. A BRET sensor can quickly detect the change of a target biomolecule quantitatively without an external electromagnetic field, e.g., UV light, which normally can damage tissue. Having been developed quite recently, this technique has evolved rapidly. Here, different bioluminescent proteins have been reviewed. In addition to a multitude of bioluminescent proteins, this manuscript focuses on the recent development of BRET sensors by utilizing quantum dots. The special size-dependent properties of quantum dots have made the BRET sensing technique attractive for the real-time monitoring of the changes of target molecules and bioimaging in vivo. This review offers a look into the basis of the technique, donor/acceptor pairs, experimental applications and prospects.
      Citation: Biosensors
      PubDate: 2019-03-16
      DOI: 10.3390/bios9010042
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 43: Nanostructured Gas Sensors for Medical and
           Health Applications: Low to High Dimensional Materials

    • Authors: Nasiri, Clarke
      First page: 43
      Abstract: Human breath has long been known as a system that can be used to diagnose diseases. With advancements in modern nanotechnology, gas sensors can now diagnose, predict, and monitor a wide range of diseases from human breath. From cancer to diabetes, the need to treat at the earliest stages of a disease to both increase patient outcomes and decrease treatment costs is vital. Therefore, it is the promising candidate of rapid and non-invasive human breath gas sensors over traditional methods that will fulfill this need. In this review, we focus on the nano-dimensional design of current state-of-the-art gas sensors, which have achieved records in selectivity, specificity, and sensitivity. We highlight the methods of fabrication for these devices and relate their nano-dimensional materials to their record performance to provide a pathway for the gas sensors that will supersede.
      Citation: Biosensors
      PubDate: 2019-03-17
      DOI: 10.3390/bios9010043
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 44: Continuous Monitoring of pH and Blood Gases
           Using Ion-Sensitive and Gas-Sensitive Field Effect Transistors Operating
           in the Amperometric Mode in Presence of Drift

    • Authors: Shahriar Jamasb
      First page: 44
      Abstract: Accurate and cost-effective integrated sensor systems for continuous monitoring of pH and blood gases continue to be in high demand. The capacity of ion-selective and Gas-sensitive field effect transistors (FETs) to serve as low-power sensors for accurate continuous monitoring of pH and blood gases is evaluated in the amperometric or current mode of operation. A stand-alone current-mode topology is employed in which a constant bias is applied to the gate with the drain current serving as the measuring signal. Compared with voltage-mode operation (e.g., in the feedback mode in ion-selective FETs), current-mode topologies offer the advantages of small size and low power consumption. However, the ion-selective FET (ISFET) and the Gas-sensitive FET (GasFET) exhibit a similar drift behavior, imposing a serious limitation on the accuracy of these sensors for continuous monitoring applications irrespective of the mode of operation. Given the slow temporal variation associated with the drift characteristics in both devices, a common post-processing technique that involves monitoring the variation of the drain current over short intervals of time can potentially allow extraction of the measuring signal in presence of drift in both sensor types. Furthermore, in the amperometric mode the static sensitivity of a FET-based sensor, given by the product of the FET transconductance and the sensitivity of the device threshold voltage to the measurand concentration, can be increased by adjusting the device design parameters. Increasing the sensitivity, while of interest in its own right, also enhances the accuracy of the proposed method. Rigorous analytical validation of the method is presented for GasFET operation in the amperometric mode. Moreover, the correction algorithm is verified experimentally using a Si3N4-gate ISFET operating in the amperometric mode to monitor pH variations ranging from 3.5 to 10.
      Citation: Biosensors
      PubDate: 2019-03-18
      DOI: 10.3390/bios9010044
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 45: Electrochemical Response of Saccharomyces
           cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa
           Seed Extracts and Antifungal Drugs

    • Authors: Patrick Kobina Arthur, Anthony Boadi Yeboah, Ibrahim Issah, Srinivasan Balapangu, Samuel K. Kwofie, Bernard O. Asimeng, E. Johan Foster, Elvis K. Tiburu
      First page: 45
      Abstract: Dioclea reflexa bioactive compounds have been shown to contain antioxidant properties. The extracts from the same plant are used in traditional medical practices to treat various diseases with impressive outcomes. In this study, ionic mobility in Saccharomyces cerevisiae cells in the presence of D. reflexa seed extracts was monitored using electrochemical detection methods to link cell death to ionic imbalance. Cells treated with ethanol, methanol, and water extracts were studied using cyclic voltammetry and cell counting to correlate electrochemical behavior and cell viability, respectively. The results were compared with cells treated with pore-forming Amphotericin b (Amp b), as well as Fluconazole (Flu) and the antimicrobial drug Rifampicin (Rif). The D. reflexa seed water extract (SWE) revealed higher anodic peak current with 58% cell death. Seed methanol extract (SME) and seed ethanol extract (SEE) recorded 31% and 22% cell death, respectively. Among the three control drugs, Flu revealed the highest cell death of about 64%, whereas Amp b and Rif exhibited cell deaths of 35% and 16%, respectively, after 8 h of cell growth. It was observed that similar to SWE, there was an increase in the anodic peak current in the presence of different concentrations of Amp b, which also correlated with enhanced cell death. It was concluded from this observation that Amp b and SWE might follow similar mechanisms to inhibit cell growth. Thus, the individual bioactive compounds from the water extracts of D. reflexa seeds could further be purified and tested to validate their potential therapeutic application. The strategy to link electrochemical behavior to biochemical responses could be a simple, fast, and robust screening technique for new drug targets and to understand the mechanism of action of such drugs against disease models.
      Citation: Biosensors
      PubDate: 2019-03-20
      DOI: 10.3390/bios9010045
      Issue No: Vol. 9, No. 1 (2019)
  • Biosensors, Vol. 9, Pages 1: Nanoparticle-Based Biosensing of
           Tuberculosis, an Affordable and Practical Alternative to Current Methods

    • Authors: Nirajan Bhusal, Sunaina Shrestha, Nisha Pote, Evangelyn C. Alocilja
      First page: 1
      Abstract: Access to community-based point-of-care, low-cost, and sensitive tuberculosis (TB) diagnostics remains an unmet need. Objective: The objective of this study was to combine principles in nanotechnology, TB biology, glycochemistry, and engineering, for the development of a nanoparticle-based colorimetric biosensing assay (NCBA) to quickly and inexpensively detect acid-fast bacilli (AFB) in sputum samples. Methods: In NCBA, the isolation of AFB from sputum samples was accomplished through glycan-coated magnetic nanoparticles (GMNP) interacting with AFB and then using a simple magnet to separate the GMNP-AFB complex. Acid-fastness and cording properties of mycobacteria were utilized to provide visually observable red-stained clumps of bacteria that were surrounded by brown nanoparticles under a light microscope on prepared smears. The NCBA technique was compared against sputum smear microscopy (SSM) and Xpert MTB/RIF in 500 samples from patients that were suspected to have TB. Results: Statistical analysis showed that NCBA had sensitivity and specificity performances in perfect agreement with Xpert MTB/RIF as gold standard for all 500 samples. SSM had a sensitivity of 40% for the same samples. Conclusion: NCBA technique yielded full agreement in terms of sensitivity and specificity with the Xpert MTB/RIF in 500 samples. The method is completed in 10–20 min through a simple process at an estimated cost of $0.10 per test. Implementation of NCBA in rural communities would help to increase case finding and case notification, and would support programs against drug-resistance. Its use at the first point-of-contact by patients in the healthcare system would facilitate quick treatment in a single clinical encounter, thus supporting the global “End TB Strategy” by 2035.
      Citation: Biosensors
      PubDate: 2018-12-24
      DOI: 10.3390/bios9010001
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 9, Pages 2: Multiplex Lateral Flow Immunoassay: An
           Overview of Strategies towards High-throughput Point-of-Need Testing

    • Authors: Laura Anfossi, Fabio Di Nardo, Simone Cavalera, Cristina Giovannoli, Claudio Baggiani
      First page: 2
      Abstract: Simultaneous measurement of different substances from a single sample is an emerging issue for achieving efficient and high-throughput detection in several fields of application. Although immunoanalytical techniques have well-established and prevailing advantages over alternative screening analytical platforms, one of the incoming challenges for immunoassay is exact multiplexing. Lateral flow immunoassay (LFIA) is a leading immunoanalytical technique for onsite analysis, thanks to its simplicity, rapidity, and cost-effectiveness. Moreover, LFIA architecture is adaptable to multiplexing, and is therefore a possible answer to the pressing demand of multiplexing point-of-need analysis. This review presents an overview of diverse approaches for multiplex LFIA, with a special focus on strategies based on new types of magnetic, fluorescent, and colored labels.
      Citation: Biosensors
      PubDate: 2018-12-26
      DOI: 10.3390/bios9010002
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 9, Pages 3: Simultaneous Detection of Dopamine and
           Serotonin—A Comparative Experimental and Theoretical Study of
           Neurotransmitter Interactions

    • Authors: Felicia S. Manciu, Marian Manciu, John D. Ciubuc, Emma M. Sundin, Katia Ochoa, Michael Eastman, William G. Durrer, Jose Guerrero, Brayant Lopez, Mahendra Subedi, Kevin E. Bennet
      First page: 3
      Abstract: With the goal of accurately detecting and quantifying the amounts of dopamine (DA) and serotonin (5-HT) in mixtures of these neurotransmitters without using any labelling, we present a detailed, comparative computational and Raman experimental study. Although discrimination between these two analytes is achievable in such mixtures for concentrations in the millimolar range, their accurate quantification remains unattainable. As shown for the first time in this work, the formation of a new composite resulting from their interactions with each other is the main reason for this lack of quantification. While this new hydrogen-bonded complex further complicates potential analyte discrimination and quantification at concentrations characteristic of physiological levels (i.e., nanomolar concentrations), it can also open new avenues for its use in drug delivery and pharmaceutical research. This remark is based not only on chemical interactions analyzed here from both theoretical and experimental approaches, but also on biological relationship, with consideration of both functional and neural proximity perspectives. Thus, this research constitutes an important contribution toward better understanding of neural processes, as well as toward possible future development of label-free biosensors.
      Citation: Biosensors
      PubDate: 2018-12-26
      DOI: 10.3390/bios9010003
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 9, Pages 4: ZIF Nanocrystal-Based Surface Acoustic Wave
           (SAW) Electronic Nose to Detect Diabetes in Human Breath

    • Authors: Fabio A. Bahos, Arianee Sainz-Vidal, Celia Sánchez-Pérez, José M. Saniger, Isabel Gràcia, María M. Saniger-Alba, Daniel Matatagui
      First page: 4
      Abstract: In the present work, a novel, portable and innovative eNose composed of a surface acoustic wave (SAW) sensor array based on zeolitic imidazolate frameworks, ZIF-8 and ZIF-67 nanocrystals (pure and combined with gold nanoparticles), as sensitive layers has been tested as a non-invasive system to detect different disease markers, such as acetone, ethanol and ammonia, related to the diagnosis and control of diabetes mellitus through exhaled breath. The sensors have been prepared by spin coating, achieving continuous sensitive layers at the surface of the SAW device. Low concentrations (5 ppm, 10 ppm and 25 ppm) of the marker analytes were measured, obtaining high sensitivities, good reproducibility, short time response and fast signal recovery.
      Citation: Biosensors
      PubDate: 2018-12-26
      DOI: 10.3390/bios9010004
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 9, Pages 5: Detection of Metabolic Changes Induced via
           Drug Treatments in Live Cancer Cells and Tissue Using Raman Imaging

    • Authors: Mioara Larion, Tyrone Dowdy, Victor Ruiz-Rodado, Matthew W. Meyer, Hua Song, Wei Zhang, Dionne Davis, Mark R. Gilbert, Adrian Lita
      First page: 5
      Abstract: Isocitrate dehydrogenase 1 (IDH1) mutations in gliomas, fibrosarcoma, and other cancers leads to a novel metabolite, D-2-hydroxyglutarate, which is proposed to cause tumorigenesis. The production of this metabolite also causes vulnerabilities in cellular metabolism, such as lowering NADPH levels. To exploit this vulnerability, we treated glioma and fibrosarcoma cells that harbor an IDH1 mutation with an inhibitor of nicotinamide adenine dinucleotide (NAD+) salvage pathway, FK866, and observed decreased viability in these cells. To understand the mechanism of action by which the inhibitor FK866 works, we used Raman imaging microscopy and identified that proteins and lipids are decreased upon treatment with the drug. Raman imaging showed a different distribution of lipids throughout the cell in the presence of the drug compared with the untreated cells. We employed nuclear magnetic resonance NMR spectroscopy and mass spectrometry to identify the classes of lipids altered. Our combined analyses point to a decrease in cell division due to loss of lipid content that contributes to membrane formation in the in vitro setting. However, the FK866 drug did not have the same potency in vivo. The use of Raman imaging microscopy indicated an opposite trend of lipid distribution in the tissue collected from treated versus untreated mice when compared with the cells. These results demonstrate the role of Raman imaging microscopy to identify and quantify metabolic changes in cancer cells and tissue.
      Citation: Biosensors
      PubDate: 2018-12-28
      DOI: 10.3390/bios9010005
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 9, Pages 6: Real Time Monitoring of a UV Light-Assisted
           Biofunctionalization Protocol Using a Nanophotonic Biosensor

    • Authors: Jad Sabek, Luis Torrijos-Morán, Amadeu Griol, Zeneida Díaz Betancor, María-José Bañuls Polo, Ángel Maquieira, Jaime García-Rupérez
      First page: 6
      Abstract: A protocol for the covalent biofunctionalization of silicon-based biosensors using a UV light-induced thiol–ene coupling (TEC) reaction has been developed. This biofunctionalization approach has been used to immobilize half antibodies (hIgG), which have been obtained by means of a tris(2-carboxyethyl)phosphine (TCEP) reduction at the hinge region, to the surface of a vinyl-activated silicon-on-insulator (SOI) nanophotonic sensing chip. The response of the sensing structures within the nanophotonic chip was monitored in real time during the biofunctionalization process, which has allowed us to confirm that the bioconjugation of the thiol-terminated bioreceptors onto the vinyl-activated sensing surface is only initiated upon UV light photocatalysis.
      Citation: Biosensors
      PubDate: 2018-12-30
      DOI: 10.3390/bios9010006
      Issue No: Vol. 9, No. 1 (2018)
  • Biosensors, Vol. 8, Pages 87: Functionalized Gold Nanoparticles as
           Biosensors for Monitoring Cellular Uptake and Localization in Normal and
           Tumor Prostatic Cells

    • Authors: Marianna Pannico, Anna Calarco, Gianfranco Peluso, Pellegrino Musto
      First page: 87
      Abstract: In the present contribution the fabrication and characterization of functionalized gold nanospheres of uniform shape and controlled size is reported. These nano-objects are intended to be used as Surface Enhanced Raman Spectroscopy (SERS) sensors for in-vitro cellular uptake and localization. Thiophenol was used as molecular reporter and was bound to the Au surface by a chemisorption process in aqueous solution. The obtained colloidal solution was highly stable and no aggregation of the single nanospheres into larger clusters was observed. The nanoparticles were incubated in human prostatic cells with the aim of developing a robust, SERS-based method to differentiate normal and tumor cell lines. SERS imaging experiments showed that tumor cells uptake considerably larger amounts of nanoparticles in comparison to normal cells (up to 950% more); significant differences were also observed in the uptake kinetics. This largely different behaviour might be exploited in diagnostic and therapeutic applications.
      Citation: Biosensors
      PubDate: 2018-10-04
      DOI: 10.3390/bios8040087
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 88: Rapid Nanofabrication of Nanostructured
           Interdigitated Electrodes (nIDEs) for Long-Term In Vitro Analysis of Human
           Induced Pluripotent Stem Cell Differentiated Cardiomyocytes

    • Authors: Cacie Hart, Avra Kundu, Kowsik Kumar, Sreekanth J. Varma, Jayan Thomas, Swaminathan Rajaraman
      First page: 88
      Abstract: Adverse cardiac events are a major cause of late-stage drug development withdrawals. Improved in vitro systems for predicting cardiotoxicity are of great interest to prevent these events and to reduce the expenses involved in the introduction of cardiac drugs into the marketplace. Interdigitated electrodes (IDEs) affixed with a culture well provide a simple, suitable solution for in vitro analysis of cells because of their high sensitivity, ease of fabrication, and label-free, nondestructive analysis. Culturing human pluripotent stem cell differentiated cardiomyocytes onto these IDEs allows for the use of the IDE–cell combination in predictive toxicity assays. IDEs with smaller interdigitated distances allow for greater sensitivity, but typically require cleanroom fabrication. In this communication, we report the definition of a simple IDE geometry on a printed nanostructured substrate, demonstrate a Cellular Index (CI) increase from 0 to 7.7 for human cardiomyocytes, and a decrease in CI from 2.3 to 1 with increased concentration of the model drug, norepinephrine. The nanostructuring results in an increased sensitivity of our 1 mm pitch IDEs when compared to traditionally fabricated IDEs with a pitch of 10 μm (100 times larger electrode gap). The entire nanostructured IDE (nIDE) is fabricated and assembled in a rapid nanofabrication environment, thus allowing for iterative design changes and robust fabrication of devices.
      Citation: Biosensors
      PubDate: 2018-10-11
      DOI: 10.3390/bios8040088
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 89: Homotransfer of FRET Reporters for Live Cell

    • Authors: Nicole E. Snell, Vishnu P. Rao, Kendra M. Seckinger, Junyi Liang, Jenna Leser, Allison E. Mancini, M. A. Rizzo
      First page: 89
      Abstract: Förster resonance energy transfer (FRET) between fluorophores of the same species was recognized in the early to mid-1900s, well before modern heterotransfer applications. Recently, homotransfer FRET principles have re-emerged in biosensors that incorporate genetically encoded fluorescent proteins. Homotransfer offers distinct advantages over the standard heterotransfer FRET method, some of which are related to the use of fluorescence polarization microscopy to quantify FRET between two fluorophores of identical color. These include enhanced signal-to-noise, greater compatibility with other optical sensors and modulators, and new design strategies based upon the clustering or dimerization of singly-labeled sensors. Here, we discuss the theoretical basis for measuring homotransfer using polarization microscopy, procedures for data collection and processing, and we review the existing genetically-encoded homotransfer biosensors.
      Citation: Biosensors
      PubDate: 2018-10-11
      DOI: 10.3390/bios8040089
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 90: In Vitro Wounding Models Using the Electric
           Cell-Substrate Impedance Sensing (ECIS)-Zθ Technology

    • Authors: Andrea Y. Gu, Dan T. Kho, Rebecca H. Johnson, E. Scott Graham, Simon J. O’Carroll
      First page: 90
      Abstract: Electric Cell-Substrate Impedance Sensing (ECIS) can produce reproducible wounding models by mechanically disrupting a cell monolayer. This study compared in vitro wound-healing using human cerebral microvascular endothelial cells (hCMVEC) with both single electrode (8W1E) and multiple electrodes (8W10E+) arrays. Measurements of hCMVEC migration and barrier functions were conducted, revealing variable levels of barrier disruption could be achieved by altering the duration and magnitude of the applied current. In all scenarios, the barrier (Rb) did not recover the strength observed prior to injury. Localization of junctional proteins following wounding were analyzed by immunocytochemistry. Following wounding, cell migration was generally faster on the 8W10E+ than the 8W1E array. Immunohistochemical analysis revealed non-viable cells remained on the 8W1E electrodes but not the 8W10E+ electrodes. However, viable cells partially remained on the 8W10E+ electrodes following wounding. In addition, the 8W10E+ electrodes demonstrated variation in cell loss across electrodes within the same well. This suggests the type of wounding is different on the two array types. However, our data show both arrays can be used to model incomplete barrier recovery and therefore both have potential for testing of drugs to improve endothelial barrier function. This is the first time that the possibility of using the 8W10E+ array as a wounding model is addressed. We highlight the differences in wounding produced between the two arrays, and can be used to study the underlying causes for impaired barrier function following CNS injuries.
      Citation: Biosensors
      PubDate: 2018-10-11
      DOI: 10.3390/bios8040090
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 91: Phosphate Modified Screen Printed Electrodes
           by LIFT Treatment for Glucose Detection

    • Authors: Francesco Milano, Livia Giotta, Daniela Chirizzi, Simos Papazoglou, Christina Kryou, Annarita De Bartolomeo, Vincenzo De Leo, Maria Rachele Guascito, Ioanna Zergioti
      First page: 91
      Abstract: The design of new materials as active layers is important for electrochemical sensor and biosensor development. Among the techniques for the modification and functionalization of electrodes, the laser induced forward transfer (LIFT) has emerged as a powerful physisorption method for the deposition of various materials (even labile materials like enzymes) that results in intimate and stable contact with target surface. In this work, Pt, Au, and glassy carbon screen printed electrodes (SPEs) treated by LIFT with phosphate buffer have been characterized by scanning electron microscopy and atomic force microscopy to reveal a flattening effect of all surfaces. The electrochemical characterization by cyclic voltammetry shows significant differences depending on the electrode material. The electroactivity of Au is reduced while that of glassy carbon and Pt is greatly enhanced. In particular, the electrochemical behavior of a phosphate LIFT treated Pt showed a marked enrichment of hydrogen adsorbed layer, suggesting an elevated electrocatalytic activity towards glucose oxidation. When Pt electrodes modified in this way were used as an effective glucose sensor, a 1–10 mM linear response and a 10 µM detection limit were obtained. A possible role of phosphate that was securely immobilized on a Pt surface, as evidenced by XPS analysis, enhancing the glucose electrooxidation is discussed.
      Citation: Biosensors
      PubDate: 2018-10-16
      DOI: 10.3390/bios8040091
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 92: Metal-Organic Frameworks for the Development
           of Biosensors: A Current Overview

    • Authors: Sergio Carrasco
      First page: 92
      Abstract: This review focuses on the fabrication of biosensors using metal-organic frameworks (MOFs) as recognition and/or transducer elements. A brief introduction discussing the importance of the development of new biosensor schemes is presented, describing these coordination polymers, their properties, applications, and the main advantages and drawbacks for the final goal. The increasing number of publications regarding the characteristics of these materials and the new micro- and nanofabrication techniques allowing the preparation of more accurate, robust, and sensitive biosensors are also discussed. This work aims to offer a new perspective from the point of view of materials science compared to other reviews focusing on the transduction mechanism or the nature of the analyte. A few examples are discussed depending on the starting materials, the integration of the MOF as a part of the biosensor and, in a deep detail, the fabrication procedure.
      Citation: Biosensors
      PubDate: 2018-10-16
      DOI: 10.3390/bios8040092
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 93: Differences Between Flash Glucose Monitor
           and Fingerprick Measurements

    • Authors: Odd Martin Staal, Heidi Marie Umbach Hansen, Sverre Christian Christiansen, Anders Lyngvi Fougner, Sven Magnus Carlsen, Øyvind Stavdahl
      First page: 93
      Abstract: Freestyle Libre (FL) is a factory calibrated Flash Glucose Monitor (FGM). We investigated Mean Absolute Relative Difference (MARD) between Self Monitoring of Blood Glucose (SMBG) and FL measurements in the first day of sensor wear in 39 subjects with Type 1 diabetes. The overall MARD was 12.3%, while the individual MARDs ranged from 4% to 25%. Five participants had a MARD ≥ 20%. We estimated bias and lag between the FL and SMBG measurements. The estimated biases range from −1.8 mmol / L to 1.4 mmol / L , and lags range from 2 min to 24 min . Bias is identified as a main cause of poor individual MARDs. The biases seem to persist in days 2–7 of sensor usage. All cases of MARD ≥ 20% in the first day are eliminated by bias correction, and overall MARD is reduced from 12.3% to 9.2%, indicating that adding support for voluntary user-supplied bias correction in the FL could improve its performance.
      Citation: Biosensors
      PubDate: 2018-10-17
      DOI: 10.3390/bios8040093
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 94: Detection Methods of Human and Animal
           Influenza Virus—Current Trends

    • Authors: Karolina Dziąbowska, Elżbieta Czaczyk, Dawid Nidzworski
      First page: 94
      Abstract: The basic affairs connected to the influenza virus were reviewed in the article, highlighting the newest trends in its diagnostic methods. Awareness of the threat of influenza arises from its ability to spread and cause a pandemic. The undiagnosed and untreated viral infection can have a fatal effect on humans. Thus, the early detection seems pivotal for an accurate treatment, when vaccines and other contemporary prevention methods are not faultless. Public health is being attacked with influenza containing new genes from a genetic assortment between animals and humankind. Unfortunately, the population does not have immunity for mutant genes and is attacked in every viral outbreak season. For these reasons, fast and accurate devices are in high demand. As currently used methods like Rapid Influenza Diagnostic Tests lack specificity, time and cost-savings, new methods are being developed. In the article, various novel detection methods, such as electrical and optical were compared. Different viral elements used as detection targets and analysis parameters, such as sensitivity and specificity, were presented and discussed.
      Citation: Biosensors
      PubDate: 2018-10-18
      DOI: 10.3390/bios8040094
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 95: Emerging Applications of Porphyrins and
           Metalloporphyrins in Biomedicine and Diagnostic Magnetic Resonance Imaging

    • Authors: Muhammad Imran, Muhammad Ramzan, Ahmad Kaleem Qureshi, Muhammad Azhar Khan, Muhammad Tariq
      First page: 95
      Abstract: In recent years, scientific advancements have constantly increased at a significant rate in the field of biomedical science. Keeping this in view, the application of porphyrins and metalloporphyrins in the field of biomedical science is gaining substantial importance. Porphyrins are the most widely studied tetrapyrrole-based compounds because of their important roles in vital biological processes. The cavity of porphyrins containing four pyrrolic nitrogens is well suited for the binding majority of metal ions to form metalloporphyrins. Porphyrins and metalloporphyrins possess peculiar photochemical, photophysical, and photoredox properties which are tunable through structural modifications. Their beneficial photophysical properties, such as the long wavelength of emission and absorption, high singlet oxygen quantum yield, and low in vivo toxicity, have drawn scientists’ interest to discover new dimensions in the biomedical field. Applications of porphyrins and metalloporphyrins have been pursued in the perspective of contrast agents for magnetic resonance imaging (MRI), photodynamic therapy (PDT) of cancer, bio-imaging, and other biomedical applications. This review discusses photophysics and the photochemistry of porphyrins and their metal complexes. Secondly, it explains the current developments and mode of action for contrast agents for MRI. Moreover, the application of porphyrin and metalloporphyrin-based molecules as a photosensitizer in PDT of cancer, the mechanism of the generation of reactive oxygen species (ROS), factors that determine the efficiency of PDT, and the developments to improve this technology are delineated. The last part explores the most recent research and developments on metalloporphyrin-based materials in bio-imaging, drug delivery, and the determination of ferrochelatase in bone marrow indicating their prospective clinical applications.
      Citation: Biosensors
      PubDate: 2018-10-19
      DOI: 10.3390/bios8040095
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 96: “The Smartphone’s Guide to the
           Galaxy”: In Situ Analysis in Space

    • Authors: Joost Nelis, Christopher Elliott, Katrina Campbell
      First page: 96
      Abstract: A human mission to Mars can be viewed as the apex of human technological achievement. However, to make this dream a reality several obstacles need to be overcome. One is devising practical ways to safeguard the crew health during the mission through the development of easy operable and compact sensors. Lately, several smartphone-based sensing devices (SBDs) with the purpose to enable the immediate sensitive detection of chemicals, proteins or pathogens in remote settings have emerged. In this critical review, the potential to piggyback these systems for in situ analysis in space has been investigated on application of a systematic keyword search whereby the most relevant articles were examined comprehensively and existing SBDs were divided into 4 relevant groups for the monitoring of crew health during space missions. Recently developed recognition elements (REs), which could offer the enhanced ability to tolerate those harsh conditions in space, have been reviewed with recommendations offered. In addition, the potential use of cell free synthetic biology to obtain long-term shelf-stable reagents was reviewed. Finally, a synopsis of the possibilities of combining novel SBD, RE and nanomaterials to create a compact sensor-platform ensuring adequate crew health monitoring has been provided.
      Citation: Biosensors
      PubDate: 2018-10-19
      DOI: 10.3390/bios8040096
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 97: Rapid Multiplexed Detection on Lateral-Flow
           Devices Using a Laser Direct-Write Technique

    • Authors: Peijun J. W. He, Ioannis N. Katis, Robert W. Eason, Collin L. Sones
      First page: 97
      Abstract: Paper-based lateral flow devices (LFDs) are regarded as ideal low-cost diagnostic solutions for point-of-care (POC) scenarios that allow rapid detection of a single analyte within a fluidic sample, and have been in common use for a decade. In recent years, there has been an increasing need for rapid and simultaneous detection of multiple analytes present within a single sample and to facilitate this, we report here a novel solution—detection using a multi-path LFD created via the precise partitioning of the single flow-path of a standard LFD using our previously reported laser direct-write (LDW) technique. The multiple flow-paths allow the simultaneous detection of the different analytes individually within each of the parallel channels without any cross-reactivity. The appearance of coloured test lines in individual channels indicates the presence of the different analytes within a sample. We successfully present the use of a LDW-patterned multi-path LFD for multiplexed detection of a biomarker panel comprising C-reactive protein (CRP) and Serum amyloid A-1 (SAA1), used for the diagnosis of bacterial infections. Overall, we demonstrate the use of our LDW technique in the creation of a novel LFD that enables multiplexed detection of two inflammation markers within a single LFD providing a detection protocol that is comparatively more efficient than the standard sequential multiplexing procedure.
      Citation: Biosensors
      PubDate: 2018-10-20
      DOI: 10.3390/bios8040097
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 98: An Aptamer-Based Capacitive Sensing Platform
           for Specific Detection of Lung Carcinoma Cells in the Microfluidic Chip

    • Authors: Ngoc-Viet Nguyen, Chun-Hao Yang, Chung-Jung Liu, Chao-Hung Kuo, Deng-Chyang Wu, Chun-Ping Jen
      First page: 98
      Abstract: Improvement of methods for reliable and early diagnosis of the cellular diseases is necessary. A biological selectivity probe, such as an aptamer, is one of the candidate recognition layers that can be used to detect important biomolecules. Lung cancer is currently a typical cause of cancer-related deaths. In this work, an electrical sensing platform is built based on amine-terminated aptamer modified-gold electrodes for the specific, label-free detection of a human lung carcinoma cell line (A549). The microdevice, that includes a coplanar electrodes configuration and a simple microfluidic channel on a glass substrate, is fabricated using standard photolithography and cast molding techniques. A procedure of self-assembly onto the gold surface is proposed. Optical microscope observations and electrical impedance spectroscopy measurements confirm that the fabricated microchip can specifically and effectively identify A549 cells. In the experiments, the capacitance element that is dominant in the change of the impedance is calculated at the appropriate frequency for evaluation of the sensitivity of the biosensor. Therefore, a simple, inexpensive, biocompatible, and selective biosensor that has the potential to detect early-stage lung cancer would be developed.
      Citation: Biosensors
      PubDate: 2018-10-20
      DOI: 10.3390/bios8040098
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 99: Red-Shifted FRET Biosensors for
           High-Throughput Fluorescence Lifetime Screening

    • Authors: Tory M. Schaaf, Ang Li, Benjamin D. Grant, Kurt Peterson, Samantha Yuen, Prachi Bawaskar, Evan Kleinboehl, Ji Li, David D. Thomas, Gregory D. Gillispie
      First page: 99
      Abstract: We have developed fluorescence resonance energy transfer (FRET) biosensors with red-shifted fluorescent proteins (FP), yielding improved characteristics for time-resolved (lifetime) fluorescence measurements. In comparison to biosensors with green and red FRET pairs (GFP/RFP), FPs that emit at longer wavelengths (orange and maroon, OFP/MFP) increased the FRET efficiency, dynamic range, and signal-to-background of high-throughput screening (HTS). OFP and MFP were fused to specific sites on the human cardiac calcium pump (SERCA2a) for detection of structural changes due to small-molecule effectors. When coupled with a recently improved HTS fluorescence lifetime microplate reader, this red-shifted FRET biosensor enabled high-precision nanosecond-resolved fluorescence decay measurements from microliter sample volumes at three minute read times per 1536-well-plate. Pilot screens with a library of small-molecules demonstrate that the OFP/MFP FRET sensor substantially improves HTS assay quality. These high-content FRET methods detect minute FRET changes with high precision, as needed to elucidate novel structural mechanisms from small-molecule or peptide regulators discovered through our ongoing HTS efforts. FRET sensors that emit at longer wavelengths are highly attractive to the FRET biosensor community for drug discovery and structural interrogation of new therapeutic targets.
      Citation: Biosensors
      PubDate: 2018-10-24
      DOI: 10.3390/bios8040099
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 100: Advanced Nanoscale Approaches to
           Single-(Bio)entity Sensing and Imaging

    • Authors: Marta Maria Pereira da Silva Neves, Daniel Martín-Yerga
      First page: 100
      Abstract: Individual (bio)chemical entities could show a very heterogeneous behaviour under the same conditions that could be relevant in many biological processes of significance in the life sciences. Conventional detection approaches are only able to detect the average response of an ensemble of entities and assume that all entities are identical. From this perspective, important information about the heterogeneities or rare (stochastic) events happening in individual entities would remain unseen. Some nanoscale tools present interesting physicochemical properties that enable the possibility to detect systems at the single-entity level, acquiring richer information than conventional methods. In this review, we introduce the foundations and the latest advances of several nanoscale approaches to sensing and imaging individual (bio)entities using nanoprobes, nanopores, nanoimpacts, nanoplasmonics and nanomachines. Several (bio)entities such as cells, proteins, nucleic acids, vesicles and viruses are specifically considered. These nanoscale approaches provide a wide and complete toolbox for the study of many biological systems at the single-entity level.
      Citation: Biosensors
      PubDate: 2018-10-26
      DOI: 10.3390/bios8040100
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 101: Photoplethysmography and Deep Learning:
           Enhancing Hypertension Risk Stratification

    • Authors: Yongbo Liang, Zhencheng Chen, Rabab Ward, Mohamed Elgendi
      First page: 101
      Abstract: Blood pressure is a basic physiological parameter in the cardiovascular circulatory system. Long-term abnormal blood pressure will lead to various cardiovascular diseases, making the early detection and assessment of hypertension profoundly significant for the prevention and treatment of cardiovascular diseases. In this paper, we investigate whether or not deep learning can provide better results for hypertension risk stratification when compared to the classical signal processing and feature extraction methods. We tested a deep learning method for the classification and evaluation of hypertension using photoplethysmography (PPG) signals based on the continuous wavelet transform (using Morse) and pretrained convolutional neural network (using GoogLeNet). We collected 121 data recordings from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC) Database, each containing arterial blood pressure (ABP) and photoplethysmography (PPG) signals. The ABP signals were utilized to extract blood pressure category labels, and the PPG signals were used to train and test the model. According to the seventh report of the Joint National Committee, blood pressure levels are categorized as normotension (NT), prehypertension (PHT), and hypertension (HT). For the early diagnosis and assessment of HT, the timely detection of PHT and the accurate diagnosis of HT are significant. Therefore, three HT classification trials were set: NT vs. PHT, NT vs. HT, and (NT + PHT) vs. HT. The F-scores of these three classification trials were 80.52%, 92.55%, and 82.95%, respectively. The tested deep method achieved higher accuracy for hypertension risk stratification when compared to the classical signal processing and feature extraction method. Additionally, the method achieved comparable results to another approach that requires electrocardiogram and PPG signals.
      Citation: Biosensors
      PubDate: 2018-10-26
      DOI: 10.3390/bios8040101
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 102: Trends in SPR Cytometry: Advances in
           Label-Free Detection of Cell Parameters

    • Authors: Richard B. M. Schasfoort, Fikri Abali, Ivan Stojanovic, Gestur Vidarsson, Leon W. M. M. Terstappen
      First page: 102
      Abstract: SPR cytometry entails the measurement of parameters from intact cells using the surface plasmon resonance (SPR) phenomenon. Specific real-time and label-free binding of living cells to sensor surfaces has been made possible through the availability of SPR imaging (SPRi) instruments and researchers have started to explore its potential in the last decade. Here we will discuss the mechanisms of detection and additionally describe the problems and issues of mammalian cells in SPR biosensing, both from our own experience and with information from the literature. Finally, we build on the knowledge and applications that has already materialized in this field to give a forecast of some exciting applications for SPRi cytometry.
      Citation: Biosensors
      PubDate: 2018-10-30
      DOI: 10.3390/bios8040102
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 103: Numerical Modeling of an Organic
           Electrochemical Transistor

    • Authors: Anna Shirinskaya, Gilles Horowitz, Jonathan Rivnay, George G. Malliaras, Yvan Bonnassieux
      First page: 103
      Abstract: We develop a numerical model for the current-voltage characteristics of organic electrochemical transistors (OECTs) based on steady-state Poisson’s, Nernst’s and Nernst–Planck’s equations. The model starts with the doping–dedoping process depicted as a moving front, when the process at the electrolyte–polymer interface and gradually moves across the film. When the polymer reaches its final state, the electrical potential and charge density profiles largely depend on the way the cations behave during the process. One case is when cations are trapped at the polymer site where dedoping occurs. In this case, the moving front stops at a point that depends on the applied voltage; the higher the voltage, the closer the stopping point to the source electrode. Alternatively, when the cations are assumed to move freely in the polymer, the moving front eventually reaches the source electrode in all cases. In this second case, cations tend to accumulate near the source electrode, and most of the polymer is uniformly doped. The variation of the conductivity of the polymer film is then calculated by integrating the density of holes all over the film. Output and transfer curves of the OECT are obtained by integrating the gate voltage-dependent conductivity from source to drain.
      Citation: Biosensors
      PubDate: 2018-10-31
      DOI: 10.3390/bios8040103
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 104: Applications of Nanomaterials for

    • Authors: Sandra Lara, André Perez-Potti
      First page: 104
      Abstract: In biomedical science among several other growing fields, the detection of specific biological agents or biomolecular markers, from biological samples is crucial for early diagnosis and decision-making in terms of appropriate treatment, influencing survival rates. In this regard, immunosensors are based on specific antibody-antigen interactions, forming a stable immune complex. The antigen-specific detection antibodies (i.e., biomolecular recognition element) are generally immobilized on the nanomaterial surfaces and their interaction with the biomolecular markers or antigens produces a physico-chemical response that modulates the signal readout. Lowering the detection limits for particular biomolecules is one of the key parameters when designing immunosensors. Thus, their design by combining the specificity and versatility of antibodies with the intrinsic properties of nanomaterials offers a plethora of opportunities for clinical diagnosis. In this review, we show a comprehensive set of recent developments in the field of nanoimmunosensors and how they are progressing the detection and validation for a wide range of different biomarkers in multiple diseases and what are some drawbacks and considerations of the uses of such devices and their expansion.
      Citation: Biosensors
      PubDate: 2018-11-01
      DOI: 10.3390/bios8040104
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 105: PEDOT Coated Thick Film Electrodes for In
           Situ Detection of Cell Adhesion in Cell Cultures

    • Authors: Heike Bartsch, Ralf Peipmann, Maren Klett, Dana Brauer, Andreas Schober, Jens Müller
      First page: 105
      Abstract: Low temperature cofired ceramics (LTCC) provide a technology for the 3-dimensional integration of sensor arrays into bioreactors covering dimensions of several hundred micrometers. Since optical control in such assemblies is not possible, the in situ detection of cell adhesion on impedance electrodes with high spatial resolution would deliver crucial information. A current limitation is the increasing impedance of microelectrodes with decreasing diameter. This study evaluates the suitability of thick film gold electrodes, pristine and coated with electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT), for the detection of cell adhesion on the electrode surface. The impedance as criterion for cell attachment is measured with a recording system for electroactive cells with the aim of improving usability. Two cell cultures with different adhesion characteristic are used for adhesion assessment on planar test chips. The impedance increase measured on individual PEDOT coated electrodes due to tight contact of cells reaches a factor of 6.8 in cultures of well-adherent HepG2 cells. Less adhered NG108-15 cells produce a maximum impedance increase by a factor of 2.6. Since the electrode impedance is significantly reduced by PEDOT coating, a reduction of the electrode diameter to values below 100 µm and spatially resolved detection is possible. The results encourage further studies using PEDOT coated thick film electrodes as bio-electronic-interfaces. We presume that such miniaturized electrodes are suitable for 3-dimensional recordings in electroactive cell cultures, providing information of local cell adhesion at the same time.
      Citation: Biosensors
      PubDate: 2018-11-02
      DOI: 10.3390/bios8040105
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 106: BCAbox Algorithm Expands Capabilities of
           Raman Microscope for Single Organelles Assessment

    • Authors: Kuzmin, Pliss, Rzhevskii, Lita, Larion
      First page: 106
      Abstract: Raman microspectroscopy is a rapidly developing technique, which has an unparalleled potential for in situ proteomics, lipidomics, and metabolomics, due to its remarkable capability to analyze the molecular composition of live cells and single cellular organelles. However, the scope of Raman spectroscopy for bio-applications is limited by a lack of software tools for express-analysis of biomolecular composition based on Raman spectra. In this study, we have developed the first software toolbox for immediate analysis of intracellular Raman spectra using a powerful biomolecular component analysis (BCA) algorithm. Our software could be easily integrated with commercial Raman spectroscopy instrumentation, and serve for precise analysis of molecular content in major cellular organelles, including nucleoli, endoplasmic reticulum, Golgi apparatus, and mitochondria of either live or fixed cells. The proposed software may be applied in broad directions of cell science, and serve for further advancement and standardization of Raman spectroscopy.
      Citation: Biosensors
      PubDate: 2018-11-10
      DOI: 10.3390/bios8040106
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 107: Raman Spectroscopy and Microscopy
           Applications in Cardiovascular Diseases: From Molecules to Organs

    • Authors: Ardalan Chaichi, Alisha Prasad, Manas Ranjan Gartia
      First page: 107
      Abstract: Noninvasive and label-free vibrational spectroscopy and microscopy methods have shown great potential for clinical diagnosis applications. Raman spectroscopy is based on inelastic light scattering due to rotational and vibrational modes of molecular bonds. It has been shown that Raman spectra provide chemical signatures of changes in biological tissues in different diseases, and this technique can be employed in label-free monitoring and clinical diagnosis of several diseases, including cardiovascular studies. However, there are very few literature reviews available to summarize the state of art and future applications of Raman spectroscopy in cardiovascular diseases, particularly cardiac hypertrophy. In addition to conventional clinical approaches such as electrocardiography (ECG), echocardiogram (cardiac ultrasound), positron emission tomography (PET), cardiac computed tomography (CT), and single photon emission computed tomography (SPECT), applications of vibrational spectroscopy and microscopy will provide invaluable information useful for the prevention, diagnosis, and treatment of cardiovascular diseases. Various in vivo and ex vivo investigations can potentially be performed using Raman imaging to study and distinguish pathological and physiological cardiac hypertrophies and understand the mechanisms of other cardiac diseases. Here, we have reviewed the recent literature on Raman spectroscopy to study cardiovascular diseases covering investigations on the molecular, cellular, tissue, and organ level.
      Citation: Biosensors
      PubDate: 2018-11-12
      DOI: 10.3390/bios8040107
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 108: Metal Oxide Nanoparticle Based
           Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in
           Wine Samples

    • Authors: Cristina Tortolini, Paolo Bollella, Rosaceleste Zumpano, Gabriele Favero, Franco Mazzei, Riccarda Antiochia
      First page: 108
      Abstract: A single-use electrochemical screen-printed electrode is reported based on biomimetic properties of nanoceria particles (CeNPs). The developed tool showed an easy approach compared to the classical spectrophotometric methods reported in literature in terms of ease of use, cost, portability, and unnecessary secondary reagents. The sensor allowed the detection of the total antioxidant capacity (TAC) in wine samples. The sensor has been optimized and characterized electrochemically and then tested with antioxidant compounds occurred in wine samples. The electrochemical CeNPs modified sensor has been used for detection of TAC in white and red commercial wines and the data compared to the 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS)-based spectrophotometric method. Finally, the obtained results have demonstrated that the proposed sensor was suitable for the simple and quick evaluation of TAC in beverage samples.
      Citation: Biosensors
      PubDate: 2018-11-14
      DOI: 10.3390/bios8040108
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 109: Electrochemical Determination of
           β-Lactoglobulin Employing a Polystyrene Bead-Modified Carbon Nanotube Ink

    • Authors: Judith Molinari, Laura Florez, Anahí Medrano, Leandro Monsalve, Gabriel Ybarra
      First page: 109
      Abstract: In this article, we introduce the use of a carboxy-functionalized waterborne carbon nanotube ink for the fabrication of an amperometric biosensor aimed at the quantification of β-lactoglobulin. Detection of this protein from cow’s milk was performed by a sandwich immunoassay onto printed carbon nanotube electrodes. The electrodes were printed using a carbon nanotube ink modified with polystyrene beads containing a high amount of carboxylic groups for protein immobilization. This strategy showed enhanced sensing performance compared to the use of oxidative treatments for the functionalization of electrodes. These electrodes showed an excellent electrochemical behavior, and proteins could be immobilized on their surface via the carbodiimide reaction. These antibody-immobilized carbon nanotube electrodes allowed for the detection of β-lactoglobulin in sub-ppm concentrations.
      Citation: Biosensors
      PubDate: 2018-11-15
      DOI: 10.3390/bios8040109
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 110: Sensors Based on Metal Nanoclusters
           Stabilized on Designed Proteins

    • Authors: Antonio Aires, Elena Lopez-Martinez, Aitziber L. Cortajarena
      First page: 110
      Abstract: Among all new nanomaterials, metal nanoclusters (NCs) have attracted special attention due to their interesting optical properties, among others. Metal NCs have been recently studied and used as sensors for different analytes. However, there is a need to explore the potential of these new sensors in a systematic manner and to develop new systems to broaden the possibilities that sensing offers to the industry. In this work, we show the potential use of repeat protein scaffolds as versatile templates for the synthesis and stabilization of various metal NCs, specifically Au, Ag, and CuNCs. The resulting protein-metal NCs hybrids are evaluated as sensors for different stimuli such as temperature, ions, or reactive oxygen species (ROS). Among the three protein-metal NCs, all performed nicely as temperature sensors, AuNCs responded to metal ions, and AgNCs were able to detect ROS.
      Citation: Biosensors
      PubDate: 2018-11-15
      DOI: 10.3390/bios8040110
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 111: Lateral Flow Immunoassay for Rapid
           Detection of Grapevine Leafroll-Associated Virus

    • Authors: Nadezhda A. Byzova, Svetlana V. Vinogradova, Elena V. Porotikova, Uliana D. Terekhova, Anatoly V. Zherdev, Boris B. Dzantiev
      First page: 111
      Abstract: Grapevine leafroll-associated virus 3 (GLRaV-3) is one of the main pathogens of grapes, causing a significant loss in yield and decrease in quality for this agricultural plant. For efficient widespread control of this infection, rapid and simple analytical techniques of on-site testing are requested as a complementary addition for the currently applied hybridization (PCR) and immunoenzyme (ELISA) approaches. The given paper presents development and approbation of the immunochromatographic assay (ICA) for rapid detection of GLRaV-3. The ICA realizes a sandwich immunoassay format with the obtaining complexes ((antibody immobilized on immunochromatographic membrane)–(virus in the sample)–(antibody immobilized on gold nanoparticles (GNP)) during sample flow along the membrane compounds of the test strip. Three preparations of GNPs were compared for detection of GLRaV-3 at different dilutions of virus-containing sample. The GNPs with maximal average diameters of 51.0 ± 7.9 nm provide GLRaV-3 detection for its maximal dilutions, being 4 times more than when using GNPs with a diameter of 28.3 ± 3.3 nm, and 8 times more than when using GNPs with a diameter of 18.5 ± 3.3 nm. Test strips have been manufactured using the largest GNPs conjugated with anti-GLRaV-3 antibodies at a ratio of 1070:1. When testing samples containing other grape wine viruses, the test strips have not demonstrated staining in the test zone, which confirms the ICA specificity. The approbation of the manufactured test strips indicated that when using ELISA as a reference method, the developed ICA is characterized by a sensitivity of 100% and a specificity of 92%. If PCR is considered as a reference method, then the sensitivity of ICA is 93% and the specificity is 92%. The proposed ICA can be implemented in one stage without the use of any additional reactants or devices. The testing results can be obtained in 10 min and detected visually. It provides significant improvement in GLRaV-3 detection, and the presented approach can be transferred for the development of test systems for other grape wine pathogens.
      Citation: Biosensors
      PubDate: 2018-11-15
      DOI: 10.3390/bios8040111
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 112: Towards Simazine Monitoring in
           Agro-Zootechnical Productions: A Yeast Cell Bioprobe for Real Samples

    • Authors: Gerardo Grasso, Ludovico Caracciolo, Giulia Cocco, Chiara Frazzoli, Roberto Dragone
      First page: 112
      Abstract: Simazine is an herbicide that is able to contaminate surface waters, ground waters, and milk/dairy products, thus posing concerns in both environmental health and food safety. A yeast-based bioprobe was utilized to detect simazine in spiked real samples of livestock drinking water and raw cow’s milk. Yeast aerobic respiration was taken as short-term toxicological endpoint. We carried out comparative measures of yeast oxygen consumption between simazine-spiked samples and blank samples. Percentage interference (%ρ) on yeast aerobic respiration was calculated through the comparison of aerobic respiration of simazine-exposed and non-exposed yeast cells. The method was optimized for raw cow’s milk samples by using boric acid as fungistatic agent in order to avoid cellular proliferation. Overall, the results have shown that simazine can be detected up to concentrations five times below the EU legal concentration limits for drinking water (0.02 ppb) and cow’s milk (2 ppb) (%ρ values of 18.53% and 20.43% respectively; %RSD ≤ 15%). Dose-effect relationships of simazine were assessed. The findings of the bioassays match reasonably well with known mechanisms of toxicity and intracellular detoxification in yeast. A correlation between fat content in milk samples and analytical performance of the bioprobe was established. Results suggest the involvement of a matrix effect, presumably due to lipid sequestration of simazine. The yeast-based bioprobe has proved to be sensitive and suitable for the detection of simazine in real samples in concentrations of interest.
      Citation: Biosensors
      PubDate: 2018-11-15
      DOI: 10.3390/bios8040112
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 113: One-Pot Synthesis of Multi-Branch Gold
           Nanoparticles and Investigation of Their SERS Performance

    • Authors: Weifeng Lv, Chenjie Gu, Shuwen Zeng, Jiaguang Han, Tao Jiang, Jun Zhou
      First page: 113
      Abstract: Gold nanoparticles with multiple branches have attracted intensive studies for their application in sensing of low trace molecules. A large number of the merits found on the gold nanoparticles for the above applications are attributed to the strong localized surface plasmon resonance excited by the incident radiation. However, a facile and flexible way of synthesizing the multi-branch gold nanoparticles with tunable localized surface plasmon resonance frequency is still a challenge for the plasmonic research field. Herein, we report an efficient one-pot synthesis of multi-branch gold nanoparticles method that resembles a seed-medicated approach while using no further chemicals except chloroauric acid, ascorbic acid and 4-(2-Hydroxyethyl)-1-piperazinyl]-ethanesulfonic acid. By controlling the amounts of ascorbic acid volumes in the reaction mixture, the morphology and the localized surface plasmon resonance frequency of the synthesized multi-branch gold nanoparticles can be manipulated conveniently. Moreover, using the 4-Mercaptobenzoic acid as the Raman reporter, the multi-branch gold nanoparticles show superior surface-enhanced Raman spectroscopy characteristics that can be potentially used in chemical and biological sensing.
      Citation: Biosensors
      PubDate: 2018-11-20
      DOI: 10.3390/bios8040113
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 114: Point-of-Care Compatibility of
           Ultra-Sensitive Detection Techniques for the Cardiac Biomarker Troponin
           I—Challenges and Potential Value

    • Authors: Brian Regan, Richard O’Kennedy, David Collins
      First page: 114
      Abstract: Cardiac biomarkers are frequently measured to provide guidance on the well-being of a patient in relation to cardiac health with many assays having been developed and widely utilised in clinical assessment. Effectively treating and managing cardiovascular disease (CVD) relies on swiftly responding to signs of cardiac symptoms, thus providing a basis for enhanced patient management and an overall better health outcome. Ultra-sensitive cardiac biomarker detection techniques play a pivotal role in improving the diagnostic capacity of an assay and thus enabling a better-informed decision. However, currently, the typical approach taken within healthcare depends on centralised laboratories performing analysis of cardiac biomarkers, thus restricting the roll-out of rapid diagnostics. Point-of-care testing (POCT) involves conducting the diagnostic test in the presence of the patient, with a short turnaround time, requiring small sample volumes without compromising the sensitivity of the assay. This technology is ideal for combatting CVD, thus the formulation of ultra-sensitive assays and the design of biosensors will be critically evaluated, focusing on the feasibility of these techniques for point-of-care (POC) integration. Moreover, there are several key factors, which in combination, contribute to the development of ultra-sensitive techniques, namely the incorporation of nanomaterials for sensitivity enhancement and manipulation of labelling methods. This review will explore the latest developments in cardiac biomarker detection, primarily focusing on the detection of cardiac troponin I (cTnI). Highly sensitive detection of cTnI is of paramount importance regarding the rapid rule-in/rule-out of acute myocardial infarction (AMI). Thus the challenges encountered during cTnI measurements are outlined in detail to assist in demonstrating the drawbacks of current commercial assays and the obstructions to standardisation. Furthermore, the added benefits of introducing multi-biomarker panels are reviewed, several key biomarkers are evaluated and the analytical benefits provided by multimarkers-based methods are highlighted.
      Citation: Biosensors
      PubDate: 2018-11-21
      DOI: 10.3390/bios8040114
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 115: Use of Electronic Noses in Seawater Quality
           Monitoring: A Systematic Review

    • Authors: Alessandro Tonacci, Francesco Sansone, Raffaele Conte, Claudio Domenici
      First page: 115
      Abstract: Electronic nose (eNose) systems are particularly appreciated for their portability, usability, relative low cost, and real-time or near real-time response. Their application finds space in several domains, including environmental monitoring. Within this field, marine monitoring is of particular scientific relevance due to the fragility of this specific environment, daily threatened by human activities that can potentially bring to catastrophic and irreversible consequences on marine wildlife. Under such considerations, a systematic review, complying with the PRISMA guidelines, was conducted covering the period up to 15 October 2018, in PubMed, ScienceDirect, and Google Scholar. Despite the relatively low number of articles published on this specific topic and the heterogeneity of the technological approaches employed, the results obtained by the various groups highlight the positive contribution eNose has given and can provide in near future for the monitoring and safeguarding of this delicate environment.
      Citation: Biosensors
      PubDate: 2018-11-23
      DOI: 10.3390/bios8040115
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 116: Cerium Oxide-Tungsten Oxide Core-Shell
           Nanowire-Based Microsensors Sensitive to Acetone

    • Authors: Milena Tomić, Milena Šetka, Ondřej Chmela, Isabel Gràcia, Eduard Figueras, Carles Cané , Stella Vallejos
      First page: 116
      Abstract: Gas sensitive cerium oxide-tungsten oxide core-shell nanowires are synthesized and integrated directly into micromachined platforms via aerosol assisted chemical vapor deposition. Tests to various volatile organic compounds (acetone, ethanol, and toluene) involved in early disease diagnosis demonstrate enhanced sensitivity to acetone for the core-shell structures in contrast to the non-modified materials (i.e., only tungsten oxide or cerium oxide). This is attributed to the high density of oxygen vacancy defects at the shell, as well as the formation of heterojunctions at the core-shell interface, which provide the modified nanowires with ‘extra’ chemical and electronic sensitization as compared to the non-modified materials.
      Citation: Biosensors
      PubDate: 2018-11-23
      DOI: 10.3390/bios8040116
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 117: A Liposomal Platform for Sensing of
           Extracellular Analytes Near Cells

    • Authors: Xiaozhou Zhang, Sabrina Heng, Jinxin Pei, Jacqueline R. Morey, Christopher A. McDevitt, Andrew D. Abell
      First page: 117
      Abstract: Cell-permeable fluorescent chemosensors (calcein, monochlorobimane, and a recently reported spiropyran-based sensor SP2) have been incorporated into yeast total lipid extract-based liposomes to suppress inherent cell permeability to allow the detection of extracellular Ca2+, GSH, and Zn2+, respectively. The repurposed sensors have enhanced aqueous solubility and the ability to quantitatively measure biologically relevant concentrations of Ca2+ (0.25 mM–1 mM), Zn2+ (6.25 µM–50 µM), and GSH (0.25 mM–1 mM) by fluorescence in aqueous media. In addition, the liposomal sensors are nontoxic to HEK293 cells and have the ability to detect exogenously added Zn2+ (1 mM), Ca2+ (1 mM), or GSH (1 mM) near cells without internalisation. This new sensing platform provides a means to repurpose a range of intracellular fluorescent sensors to specifically detect extracellular analytes, while also improving biocompatibility for overall enhanced use in a wide range of biomedical applications.
      Citation: Biosensors
      PubDate: 2018-11-26
      DOI: 10.3390/bios8040117
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 118: Microwave Spectroscopic Detection of Human
           Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

    • Authors: Rodica Elena Ionescu, Raphael Selon, Nicolas Pocholle, Lan Zhou, Anna Rumyantseva, Eric Bourillot, Eric Lesniewska
      First page: 118
      Abstract: Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.
      Citation: Biosensors
      PubDate: 2018-11-27
      DOI: 10.3390/bios8040118
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 119: Assessing the Potential Deployment of
           Biosensors for Point-of-Care Diagnostics in Developing Countries:
           Technological, Economic and Regulatory Aspects

    • Authors: Daniel Migliozzi, Thomas Guibentif
      First page: 119
      Abstract: Infectious diseases and antimicrobial resistance are major burdens in developing countries, where very specific conditions impede the deployment of established medical infrastructures. Since biosensing devices are nowadays very common in developed countries, particularly in the field of diagnostics, they are at a stage of maturity at which other potential outcomes can be explored, especially on their possibilities for multiplexing and automation to reduce the time-to-results. However, the translation is far from being trivial. In order to understand the factors and barriers that can facilitate or hinder the application of biosensors in resource-limited settings, we analyze the context from several angles. First, the technology of the devices themselves has to be rethought to take into account the specific needs and the available means of these countries. For this, we describe the partition of a biosensor into its functional shells, which define the information flow from the analyte to the end-user, and by following this partition we assess the strengths and weaknesses of biosensing devices in view of their specific technological development and challenging deployment in low-resource environments. Then, we discuss the problem of cost reduction by pointing out transversal factors, such as throughput and cost of mistreatment, that need to be re-considered when analyzing the cost-effectiveness of biosensing devices. Beyond the technical landscape, the compliance with regulations is also a major aspect that is described with its link to the validation of the devices and to the acceptance from the local medical personnel. Finally, to learn from a successful case, we analyze a breakthrough inexpensive biosensor that is showing high potential with respect to many of the described aspects. We conclude by mentioning both some transversal benefits of deploying biosensors in developing countries, and the key factors that can drive such applications.
      Citation: Biosensors
      PubDate: 2018-11-29
      DOI: 10.3390/bios8040119
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 120: Chiral Plasmonic Biosensors

    • Authors: Vladimir E. Bochenkov, Tatyana I. Shabatina
      First page: 120
      Abstract: Biosensing requires fast, selective, and highly sensitive real-time detection of biomolecules using efficient simple-to-use techniques. Due to a unique capability to focus light at nanoscale, plasmonic nanostructures provide an excellent platform for label-free detection of molecular adsorption by sensing tiny changes in the local refractive index or by enhancing the light-induced processes in adjacent biomolecules. This review discusses the opportunities provided by surface plasmon resonance in probing the chirality of biomolecules as well as their conformations and orientations. Various types of chiral plasmonic nanostructures and the most recent developments in the field of chiral plasmonics related to biosensing are considered.
      Citation: Biosensors
      PubDate: 2018-12-01
      DOI: 10.3390/bios8040120
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 121: Non-Invasive Diagnosis of Diabetes by
           Volatile Organic Compounds in Urine Using FAIMS and Fox4000 Electronic

    • Authors: Siavash Esfahani, Alfian Wicaksono, Ella Mozdiak, Ramesh P. Arasaradnam, James A. Covington
      First page: 121
      Abstract: The electronic nose (eNose) is an instrument designed to mimic the human olfactory system. Usage of eNose in medical applications is more popular than ever, due to its low costs and non-invasive nature. The eNose sniffs the gases and vapours that emanate from human waste (urine, breath, and stool) for the diagnosis of variety of diseases. Diabetes mellitus type 2 (DM2) affects 8.3% of adults in the world, with 43% being underdiagnosed, resulting in 4.9 million deaths per year. In this study, we investigated the potential of urinary volatile organic compounds (VOCs) as novel non-invasive diagnostic biomarker for diabetes. In addition, we investigated the influence of sample age on the diagnostic accuracy of urinary VOCs. We analysed 140 urine samples (73 DM2, 67 healthy) with Field-Asymmetric Ion Mobility Spectrometry (FAIMS); a type of eNose; and FOX 4000 (AlphaM.O.S, Toulouse, France). Urine samples were collected at UHCW NHS Trust clinics over 4 years and stored at −80 °C within two hours of collection. Four different classifiers were used for classification, specifically Sparse Logistic Regression, Random Forest, Gaussian Process, and Support Vector on both FAIMS and FOX4000. Both eNoses showed their capability of diagnosing DM2 from controls and the effect of sample age on the discrimination. FAIMS samples were analysed for all samples aged 0–4 years (AUC: 88%, sensitivity: 87%, specificity: 82%) and then sub group samples aged less than a year (AUC (Area Under the Curve): 94%, Sensitivity: 92%, specificity: 100%). FOX4000 samples were analysed for all samples aged 0–4 years (AUC: 85%, sensitivity: 77%, specificity: 85%) and a sub group samples aged less than 18 months: (AUC: 94%, sensitivity: 90%, specificity: 89%). We demonstrated that FAIMS and FOX 4000 eNoses can discriminate DM2 from controls using urinary VOCs. In addition, we showed that urine sample age affects discriminative accuracy.
      Citation: Biosensors
      PubDate: 2018-12-01
      DOI: 10.3390/bios8040121
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 122: Evaluation of Continuous Lactate Monitoring
           Systems within a Heparinized In Vivo Porcine Model Intravenously and

    • Authors: Alexander Wolf, Kevin Renehan, Kenneth K. Y. Ho, Benjamin D. Carr, Chieh V. Chen, Marie S. Cornell, Minyi Ye, Alvaro Rojas-Peña, Hao Chen
      First page: 122
      Abstract: We present an animal model used to evaluate the in vivo performance of electrochemical amperometric continuous lactate sensors compared to blood gas instruments. Electrochemical lactate sensors were fabricated, placed into 5 Fr central venous catheters (CVCs), and paired with wireless potentiostat devices. Following in vivo evaluation and calibration, sensors were placed within the jugular and femoral veins of a porcine subject as a preliminary assessment of in vivo measurement accuracy. The mobile electronic circuit potentiostat devices supplied the operational voltage for the sensors, measured the resultant steady-state current, and recorded the sensor response values in internal memory storages. An in vivo time trace of implanted intravenous (IV) sensors demonstrated lactate values that correlated well with the discrete measurements of blood samples on a benchtop point-of-care sensor-based instrument. Currents measured continuously from the implanted lactate sensors over 10 h were converted into lactate concentration values through use of a two-point in vivo calibration. Study shows that intravenously implanted sensors had more accurate readings, faster peak-reaching rates, and shorter peak-detection times compared to subcutaneously placed sensors. IV implanted and subcutaneously placed sensors closer to the upper body (in this case neck) showed faster response rates and more accurate measurements compared to those implanted in the lower portion of the porcine model. This study represents an important milestone not only towards continuous lactate monitoring for early diagnosis and intervention in neonatal patients with congenital heart disease undergoing cardiopulmonary bypass surgeries, but also in the intervention of critical ill patients in the Intensive Care Units or during complex surgical procedures.
      Citation: Biosensors
      PubDate: 2018-12-04
      DOI: 10.3390/bios8040122
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 123: Biomolecular Component Analysis of
           Phospholipids Composition in Live HeLa Cells

    • Authors: Svitlana M. Levchenko, Junle Qu
      First page: 123
      Abstract: The alteration of the phospholipid composition within the cell, in particular the ratio between saturated and unsaturated fatty acids, can serve as an important biomarker to prognosis of the disease progression (e.g., fatty-liver disease, prostate cancer, or neurodegenerative disorders). Major techniques for lipid analysis in biological samples require a lipid extraction procedure that is not compatible with live cell studies. To address this challenge, we apply microRaman-Biomolecular Component Analysis (BCA) for comparative analysis of phospholipid composition and sensing the saturation degree of fatty acid lipid chain in live HeLa cells and lipids extracted from HeLa cells. After processing raw Raman data, acquired in lipid droplets (LDs) free cytoplasmic area, LDs and extracted lipids with BCA, the lipid component was isolated. Despite the similarity in general profiles of processed Raman spectra acquired in live cells and extracted lipids, some clear differences that reflect diversity in their phospholipids composition were revealed. Furthermore, using the direct relation between the number of double bonds in the fatty acid chain and the intensity ratio of the corresponding Raman bands, the saturation degree of fatty acids was estimated.
      Citation: Biosensors
      PubDate: 2018-12-05
      DOI: 10.3390/bios8040123
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 124: A Theoretical Study of Surface Mode
           Propagation with a Guiding Layer of GaN/Sapphire Hetero-Structure in
           Liquid Medium

    • Authors: M. Wee, Muhammad Jaafar, Mohd Faiz, Chang Dee, Burhanuddin Majlis
      First page: 124
      Abstract: Gallium Nitride (GaN) is considered as the second most popular semiconductor material in industry after silicon. This is due to its wide applications encompassing Light Emitting Diode (LED) and power electronics. In addition, its piezoelectric properties are fascinating to be explored as electromechanical material for the development of diverse microelectromechanical systems (MEMS) application. In this article, we conducted a theoretical study concerning surface mode propagation, especially Rayleigh and Sezawa mode in the layered GaN/sapphire structure with the presence of various guiding layers. It is demonstrated that the increase in thickness of guiding layer will decrease the phase velocities of surface mode depending on the material properties of the layer. In addition, the Q-factor value indicating the resonance properties of surface mode appeared to be affected with the presence of fluid domain, particularly in the Rayleigh mode. Meanwhile, the peak for Sezawa mode shows the highest Q factor and is not altered by the presence of fluid. Based on these theoretical results using the finite element method, it could contribute to the development of a GaN-based device to generate surface acoustic wave, especially in Sezawa mode which could be useful in acoustophoresis, lab on-chip and microfluidics applications.
      Citation: Biosensors
      PubDate: 2018-12-05
      DOI: 10.3390/bios8040124
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 125: A Passive Microfluidic Device Based on
           Crossflow Filtration for Cell Separation Measurements: A
           Spectrophotometric Characterization

    • Authors: Vera Faustino, Susana Catarino, Diana Pinho, Rui Lima, Graça Minas
      First page: 125
      Abstract: Microfluidic devices have been widely used as a valuable research tool for diagnostic applications. Particularly, they have been related to the successful detection of different diseases and conditions by assessing the mechanical properties of red blood cells (RBCs). Detecting deformability changes in the cells and being able to separate those cells may be a key factor in assuring the success of detection of some blood diseases with diagnostic devices. To detect and separate the chemically modified RBCs (mimicking disease-infected RBCs) from healthy RBCs, the present work proposes a microfluidic device comprising a sequence of pillars with different gaps and nine different outlets used to evaluate the efficiency of the device by measuring the optical absorption of the collected samples. This latter measurement technique was tested to distinguish between healthy RBCs and RBCs chemically modified with glutaraldehyde. The present study indicates that it was possible to detect a slight differences between the samples using an optical absorption spectrophotometric setup. Hence, the proposed microfluidic device has the potential to perform in one single step a partial passive separation of RBCs based on their deformability.
      Citation: Biosensors
      PubDate: 2018-12-09
      DOI: 10.3390/bios8040125
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 126: Development of DNA Pair Biosensor for
           Quantization of Nuclear Factor Kappa B

    • Authors: Zhaohui Wang, Pak Kin Wong
      First page: 126
      Abstract: Nuclear factor kappa B (NF-κB), regulating the expression of several genes that mediate the inflammatory responses and cell proliferation, is one of the therapeutic targets for chronic inflammatory disease and cancer. A novel molecular binding scheme for the detection of NF-κB was investigated for its affinity to Ig-κB DNA composed by dye and quencher fluorophores, and this specificity is confirmed by competing with the DNA sequence that is complementary to the Ig-κB DNA. We create a normalization equation to remove the negative effects from the various initial fluorophore concentrations and the background noise. We also found that a periodic shaking at a frequency could help to stabilize the DNA–protein binding. The calibration experiment, using purified p50 (NF-κB), shows that this molecular probe biosensor has a detection limit on the order of nanomolar. The limit of detection is determined by the binding performance of dye and quencher oligonucleotides, and only a small portion of probes are stabilized by DNA-binding protein NF-κB. The specificity experiment also shows that p50/p65 heterodimer has the highest affinity for Ig-κB DNA; p65 homodimer binds with intermediate affinity, whereas p50 shows the lowest binding affinity, and Ig-κB DNA is not sensitive to BSA (bovine albumin serum). The experiment of HeLa nuclear extract shows that TNF-α stimulated HeLa nuclear extract has higher affinity to Ig-κB DNA than non-TNF-stimulated HeLa nuclear extract (4-h serum response). Therefore, the molecular binding scheme provides a rapid, quantitative, high throughput, and automated measurement of the DNA-binding protein NF-κB at low cost, which is beneficial for automated drug screening systems.
      Citation: Biosensors
      PubDate: 2018-12-10
      DOI: 10.3390/bios8040126
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 127: MRI Study of the Influence of Surface
           Coating Aging on the In Vivo Biodistribution of Iron Oxide Nanoparticles

    • Authors: Susana Carregal-Romero, Sandra Plaza-García, Rafael Piñol, José L. Murillo, Jesús Ruiz-Cabello, Daniel Padro, Angel Millán, Pedro Ramos-Cabrer
      First page: 127
      Abstract: Medical imaging is an active field of research that fosters the necessity for novel multimodal imaging probes. In this line, nanoparticle-based contrast agents are of special interest, since those can host functional entities either within their interior, reducing potential toxic effects of the imaging tracers, or on their surface, providing high payloads of probes, due to their large surface-to-volume ratio. The long-term stability of the particles in solution is an aspect usually under-tackled during probe design in research laboratories, since their performance is generally tested briefly after synthesis. This may jeopardize a later translation into practical medical devices, due to stability reasons. To dig into the effects of nanoparticle aging in solution, with respect to their behavior in vivo, iron oxide stealth nanoparticles were used at two stages (3 weeks vs. 9 months in solution), analyzing their biodistribution in mice. Both sets of nanoprobes showed similar sizes, zeta potentials, and morphology, as observed by dynamic light scattering (DLS) and transmission electronic microscopy (TEM), but fresh nanoparticles accumulated in the kidneys after systemic administration, while aged ones accumulated in liver and spleen, confirming an enormous effect of particle aging on their in vivo behavior, despite barely noticeable changes perceived on a simple inspection of their structural integrity.
      Citation: Biosensors
      PubDate: 2018-12-12
      DOI: 10.3390/bios8040127
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 128: Magnetic Nanoparticle-Based Biosensing
           Assay Quantitatively Enhances Acid-Fast Bacilli Count in Paucibacillary
           Pulmonary Tuberculosis

    • Authors: Cristina Gordillo-Marroquín, Anaximandro Gómez-Velasco, Héctor J. Sánchez-Pérez, Kasey Pryg, John Shinners, Nathan Murray, Sergio G. Muñoz-Jiménez, Allied Bencomo-Alerm, Adriana Gómez-Bustamante, Letisia Jonapá-Gómez, Natán Enríquez-Ríos, Miguel Martín, Natalia Romero-Sandoval, Evangelyn C. Alocilja
      First page: 128
      Abstract: A new method using a magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was compared with sputum smear microscopy (SSM) for the detection of pulmonary tuberculosis (PTB) in sputum samples. Studies were made to compare the NCBA against SSM using sputum samples collected from PTB patients prior to receiving treatment. Experiments were also conducted to determine the appropriate concentration of glycan-functionalized magnetic nanoparticles (GMNP) used in the NCBA and to evaluate the optimal digestion/decontamination solution to increase the extraction, concentration and detection of acid-fast bacilli (AFB). The optimized NCBA consisted of a 1:1 mixture of 0.4% NaOH and 4% N-acetyl-L-cysteine (NALC) to homogenize the sputum sample. Additionally, 10 mg/mL of GMNP was added to isolate and concentrate the AFB. All TB positive sputum samples were identified with an increased AFB count of 47% compared to SSM, demonstrating GMNP’s ability to extract and concentrate AFB. Results showed that NCBA increased AFB count compared to SSM, improving the grade from “1+” (in SSM) to “2+”. Extending the finding to paucibacillary cases, there is the likelihood of a “scant” grade to become “1+”. The assay uses a simple magnet and only costs $0.10/test. NCBA has great potential application in TB control programs.
      Citation: Biosensors
      PubDate: 2018-12-12
      DOI: 10.3390/bios8040128
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 129: Preserved Microarrays for Simultaneous
           Detection and Identification of Six Fungal Potato Pathogens with the Use
           of Real-Time PCR in Matrix Format

    • Authors: Maksim Nikitin, Ksenia Deych, Inessa Grevtseva, Natalya Girsova, Maria Kuznetsova, Mikhail Pridannikov, Vitaly Dzhavakhiya, Natalia Statsyuk, Alexander Golikov
      First page: 129
      Abstract: Fungal diseases of plants are of great economic importance causing 70–80% of crop losses associated with microbial plant pathogens. Advanced on-site disease diagnostics is very important to maximize crop productivity. In this study, diagnostic systems have been developed for simultaneous detection and identification of six fungal pathogens using 48-well microarrays (micromatrices) for qPCR. All oligonucleotide sets were tested for their specificity using 59 strains of target and non-target species. Detection limit of the developed test systems varied from 0.6 to 43.5 pg of DNA depending on target species with reproducibility within 0.3−0.7% (standard deviation). Diagnostic efficiency of test systems with stabilized and freeze-dried PCR master-mixes did not significantly differ from that of freshly prepared microarrays, though detection limit increased. Validation of test systems on 30 field samples of potato plants showed perfect correspondence with the results of morphological identification of pathogens. Due to the simplicity of the analysis and the automated data interpretation, the developed microarrays have good potential for on-site use by technician-level personnel, as well as for high-throughput monitoring of fungal potato pathogens.
      Citation: Biosensors
      PubDate: 2018-12-13
      DOI: 10.3390/bios8040129
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 130: Rapid Antibody Selection Using Surface
           Plasmon Resonance for High-Speed and Sensitive Hazelnut Lateral Flow

    • Authors: Georgina M.S. Ross, Maria G.E.G. Bremer, Jan H. Wichers, Aart van Amerongen, Michel W.F. Nielen
      First page: 130
      Abstract: Lateral Flow Immunoassays (LFIAs) allow for rapid, low-cost, screening of many biomolecules such as food allergens. Despite being classified as rapid tests, many LFIAs take 10–20 min to complete. For a really high-speed LFIA, it is necessary to assess antibody association kinetics. By using a label-free optical technique such as Surface Plasmon Resonance (SPR), it is possible to screen crude monoclonal antibody (mAb) preparations for their association rates against a target. Herein, we describe an SPR-based method for screening and selecting crude anti-hazelnut antibodies based on their relative association rates, cross reactivity and sandwich pairing capabilities, for subsequent application in a rapid ligand binding assay. Thanks to the SPR selection process, only the fast mAb (F-50-6B12) and the slow (S-50-5H9) mAb needed purification for labelling with carbon nanoparticles to exploit high-speed LFIA prototypes. The kinetics observed in SPR were reflected in LFIA, with the test line appearing within 30 s, almost two times faster when F-50-6B12 was used, compared with S-50-5H9. Additionally, the LFIAs have demonstrated their future applicability to real life samples by detecting hazelnut in the sub-ppm range in a cookie matrix. Finally, these LFIAs not only provide a qualitative result when read visually, but also generate semi-quantitative data when exploiting freely downloadable smartphone apps.
      Citation: Biosensors
      PubDate: 2018-12-14
      DOI: 10.3390/bios8040130
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 131: Label-Free SERS Discrimination and In Situ

    • Authors: Niccolò Paccotti, Francesco Boschetto, Satoshi Horiguchi, Elia Marin, Alessandro Chiadò, Chiara Novara, Francesco Geobaldo, Fabrizio Giorgis, Giuseppe Pezzotti
      First page: 131
      Abstract: Surface enhanced Raman spectroscopy (SERS) has been proven suitable for identifying and characterizing different bacterial species, and to fully understand the chemically driven metabolic variations that occur during their evolution. In this study, SERS was exploited to identify the cellular composition of Gram-positive and Gram-negative bacteria by using mesoporous silicon-based substrates decorated with silver nanoparticles. The main differences between the investigated bacterial strains reside in the structure of the cell walls and plasmatic membranes, as well as their biofilm matrix, as clearly noticed in the corresponding SERS spectrum. A complete characterization of the spectra was provided in order to understand the contribution of each vibrational signal collected from the bacterial culture at different times, allowing the analysis of the bacterial populations after 12, 24, and 48 h. The results show clear features in terms of vibrational bands in line with the bacterial growth curve, including an increasing intensity of the signals during the first 24 h and their subsequent decrease in the late stationary phase after 48 h of culture. The evolution of the bacterial culture was also confirmed by fluorescence microscope images.
      Citation: Biosensors
      PubDate: 2018-12-15
      DOI: 10.3390/bios8040131
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 132: Recent Progress in Surface Plasmon
           Resonance Biosensors (2016 to Mid-2018)

    • Authors: Gorodkiewicz, Lukaszewski
      First page: 132
      Abstract: : More than 50 papers on surface plasmon resonance biosensors, published between 2016 and mid-2018, are reviewed. Papers concerning the determination of large particles such as vesicles, exosomes, cancer cells, living cells, stem cells, and microRNA are excluded, as these are covered by a very recent review. The reviewed papers are categorized into five groups, depending on the degree of maturity of the reported solution; ranging from simple marker detection to clinical application of a previously developed biosensor. Instrumental solutions and details of biosensor construction are analyzed, including the chips, receptors, and linkers used, as well as calibration strategies. Biosensors with a sandwich structure containing different nanoparticles are considered separately, as are SPR (Surface Plasmon Resonance) applications for investigating the interactions of biomolecules. An analysis is also made of the markers determined using the biosensors. In conclusion, there is shown to be a growing number of SPR applications in the solution of real clinical problems.
      Citation: Biosensors
      PubDate: 2018-12-16
      DOI: 10.3390/bios8040132
      Issue No: Vol. 8, No. 4 (2018)
  • Biosensors, Vol. 8, Pages 78: Design and Fabrication of a BiCMOS
           Dielectric Sensor for Viscosity Measurements: A Possible Solution for
           Early Detection of COPD

    • Authors: Pouya Soltani Zarrin, Farabi Ibne Jamal, Subhajit Guha, Jan Wessel, Dietmar Kissinger, Christian Wenger
      First page: 78
      Abstract: The viscosity variation of sputum is a common symptom of the progression of Chronic Obstructive Pulmonary Disease (COPD). Since the hydration of the sputum defines its viscosity level, dielectric sensors could be used for the characterization of sputum samples collected from patients for early diagnosis of COPD. In this work, a CMOS-based dielectric sensor for the real-time monitoring of sputum viscosity was designed and fabricated. A proper packaging for the ESD-protection and short-circuit prevention of the sensor was developed. The performance evaluation results show that the radio frequency sensor is capable of measuring dielectric constant of biofluids with an accuracy of 4.17%. Integration of this sensor into a portable system will result in a hand-held device capable of measuring viscosity of sputum samples of COPD-patients for diagnostic purposes.
      Citation: Biosensors
      PubDate: 2018-08-21
      DOI: 10.3390/bios8030078
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 79: Breathable Dry Silver/Silver Chloride
           Electronic Textile Electrodes for Electrodermal Activity Monitoring

    • Authors: Peter A. Haddad, Amir Servati, Saeid Soltanian, Frank Ko, Peyman Servati
      First page: 79
      Abstract: The focus of this study is to design and integrate silver/silver chloride (Ag/AgCl) electronic textile (e-textile) electrodes into different textile substrates to evaluate their ability to monitor electrodermal activity (EDA). Ag/AgCl e-textiles were stitched into woven textiles of cotton, nylon, and polyester to function as EDA monitoring electrodes. EDA stimulus responses detected by dry e-textile electrodes at various locations on the hand were compared to the EDA signals collected by dry solid Ag/AgCl electrodes. 4-h EDA data with e-textile and clinically conventional rigid electrodes were compared in relation to skin surface temperature. The woven cotton textile substrate with e-textile electrodes (0.12 cm2 surface area, 0.40 cm distance) was the optimal material to detect the EDA stimulus responses with the highest average Pearson correlation coefficient of 0.913 ± 0.041 when placed on the distal phalanx of the middle finger. In addition, differences with EDA waveforms recorded on various fingers were observed. Trends of long-term measurements showed that skin surface temperature affected EDA signals recorded by non-breathable electrodes more than when e-textile electrodes were used. The effective design criteria outlined for e-textile electrodes can promote the development of comfortable and unobtrusive EDA monitoring systems, which can help improve our knowledge of the human neurological system.
      Citation: Biosensors
      PubDate: 2018-08-24
      DOI: 10.3390/bios8030079
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 80: Surface Plasmon Resonance Optical Sensor: A
           Review on Light Source Technology

    • Authors: Briliant Adhi Prabowo, Agnes Purwidyantri, Kou-Chen Liu
      First page: 80
      Abstract: The notion of surface plasmon resonance (SPR) sensor research emerged more than eight decades ago from the first observed phenomena in 1902 until the first introduced principles for gas sensing and biosensing in 1983. The sensing platform has been hand-in-hand with the plethora of sensing technology advancement including nanostructuring, optical technology, fluidic technology, and light source technology, which contribute to substantial progress in SPR sensor evolution. Nevertheless, the commercial products of SPR sensors in the market still require high-cost investment, component, and operation, leading to unaffordability for their implementation in a low-cost point of care (PoC) or laboratories. In this article, we present a comprehensive review of SPR sensor development including the state of the art from a perspective of light source technology trends. Based on our review, the trend of SPR sensor configurations, as well as its methodology and optical designs are strongly influenced by the development of light source technology as a critical component. These simultaneously offer new underlying principles of SPR sensor towards miniaturization, portability, and disposability features. The low-cost solid-state light source technology, such as laser diode, light-emitting diode (LED), organic light emitting diode (OLED) and smartphone display have been reported as proof of concept for the future of low-cost SPR sensor platforms. Finally, this review provides a comprehensive overview, particularly for SPR sensor designers, including emerging engineers or experts in this field.
      Citation: Biosensors
      PubDate: 2018-08-26
      DOI: 10.3390/bios8030080
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 81: Modified Biosensor for Cholinesterase
           Inhibitors with Guinea Green B as the Color Indicator

    • Authors: Vladimír Pitschmann, Lukáš Matějovský, Martin Lobotka, Jan Dědič, Martin Urban, Michal Dymák
      First page: 81
      Abstract: Colorimetric biosensors of cholinesterase inhibitors are ideal for fast, reliable, and very simple detection of agents in air, in water, and on surfaces. This paper describes an innovation of the Czech Detehit biosensor, which is based on a biochemical enzymatic reaction visualized by using Ellman’s reagent as a chromogenic indicator. The modification basically consists of a much more distinct color response of the biosensor, attained through optimization of the reaction system by using Guinea Green B as the indicator. The performance of the modified biosensor was verified on the chemical warfare agents (sarin, soman, cyclosarin, and VX) in water. The detection limits ascertained visually (with the naked eye) were about 0.001 µg/mL in water (exposure time 60 s, inhibition efficiency 25%).
      Citation: Biosensors
      PubDate: 2018-09-04
      DOI: 10.3390/bios8030081
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 82: Fluorescent Nanosensor Based on Molecularly
           Imprinted Polymers Coated on Graphene Quantum Dots for Fast Detection of

    • Authors: Tongchang Zhou, Arnab Halder, Yi Sun
      First page: 82
      Abstract: In this work, we developed a novel fluorescent sensor by combining molecularly imprinted polymers (MIPs) with graphene quantum dots (GQDs) for the determination of tetracycline (TC) in aqueous samples. Firstly, we developed a one-pot green method to synthesize GQDs as the fluorescent probes. GQDs with carboxyl groups or amino groups were fabricated. It was found that carboxyl groups played an important role in the fluorescence quenching. Based on these findings, the GQDs-MIPs microspheres were prepared using a sol-gel process. GQDs-MIPs showed strong fluorescent emission at 410 nm when excited at 360 nm, and the fluorescence was quenched in the presence of TC. Under optimum conditions, the fluorescence intensity of GQDs-MIPs decreased in response to the increase of TC concentration. The linear rage was from 1.0 to 104 µg·L−1, and the limit of detection was determined to be 1 µg·L−1. The GQDs-MIPs also demonstrated high selectivity towards TC. The fluorescent sensor was successfully applied for the detection of TC in real spiked milk samples.
      Citation: Biosensors
      PubDate: 2018-09-05
      DOI: 10.3390/bios8030082
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 83: Chemical Sensing Employing Plant Electrical
           Signal Response-Classification of Stimuli Using Curve Fitting Coefficients
           as Features

    • Authors: Shre Kumar Chatterjee, Obaid Malik, Siddharth Gupta
      First page: 83
      Abstract: In order to exploit plants as environmental biosensors, previous researches have been focused on the electrical signal response of the plants to different environmental stimuli. One of the important outcomes of those researches has been the extraction of meaningful features from the electrical signals and the use of such features for the classification of the stimuli which affected the plants. The classification results are dependent on the classifier algorithm used, features extracted and the quality of data. This paper presents an innovative way of extracting features from raw plant electrical signal response to classify the external stimuli which caused the plant to produce such a signal. A curve fitting approach in extracting features from the raw signal for classification of the applied stimuli has been adopted in this work, thereby evaluating whether the shape of the raw signal is dependent on the stimuli applied. Four types of curve fitting models—Polynomial, Gaussian, Fourier and Exponential, have been explored. The fitting accuracy (i.e., fitting of curve to the actual raw signal) depicted through R-squared values has allowed exploration of which curve fitting model performs best. The coefficients of the curve fit models were then used as features. Thereafter, using simple classification algorithms such as Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA) etc. within the curve fit coefficient space, we have verified that within the available data, above 90% classification accuracy can be achieved. The successful hypothesis taken in this work will allow further research in implementing plants as environmental biosensors.
      Citation: Biosensors
      PubDate: 2018-09-10
      DOI: 10.3390/bios8030083
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 84: Optimization and Application of
           Electrochemical Transducer for Detection of Specific Oligonucleotide
           Sequence for Mycobacterium tuberculosis

    • Authors: Ricardo A. M. S. Corrêa, Filipe S. da Cruz, Cátia C. Santos, Thiago C. Pimenta, Diego L. Franco, Lucas F. Ferreira
      First page: 84
      Abstract: In this study, the electropolymerization of 4-hydroxyphenylacetic acid (4-HPA) over graphite electrodes (GE) was optimized, aiming its application as a functionalized electrochemical platform for oligonucleotides immobilization. It was investigated for the number of potential cycles and the scan rate influence on the monomer electropolymerization by using cyclic voltammetry technique. It was observed that the polymeric film showed a redox response in the region of +0.53/+0.38 V and the increase in the number of cycles produces more electroactive platforms because of the better electrode coverage. On the other hand, the decrease of scan rate produces more electroactive platforms because of the occurrence of more organized coupling. Scanning electron microscopy (SEM) images showed that the number of potential cycles influences the coverage and morphology of the electrodeposited polymeric film. However, the images also showed that at different scan rates a more organized material was produced. The influence of these optimized polymerization parameters was evaluated both in the immobilization of specific oligonucleotides and in the detection of hybridization with complementary target. Poly(4-HPA)/GE platform has shown efficient and sensitive for oligonucleotides immobilization, as well as for a hybridization event with the complementary oligonucleotide in all investigated cases. The electrode was modified with 100 cycles at 75 mV/s presented the best responses in function of the amplitude at the monitored peak current values for the Methylene Blue and Ethidium Bromide intercalators. The construction of the genosensor to detect a specific oligonucleotide sequence for the Mycobacterium tuberculosis bacillus confirmed the results regarding the poly(4-HPA)/GE platform efficiency since it showed excellent sensitivity. The limit of detection and the limit of quantification was found to be 0.56 (±0.05) μM and 8.6 (±0.7) μM, respectively operating with very low solution volumes (15 µL of probe and 10 µL target). The biosensor development was possible with optimization of the probe adsorption parameters and target hybridization, which led to an improvement in the decrease of the Methylene Blue (MB) reduction signal from 14% to 34%. In addition, interference studies showed that the genosensor has satisfactory selectivity since the hybridization with a non-specific probe resulted in a signal decrease (46% lower) when compared to the specific target.
      Citation: Biosensors
      PubDate: 2018-09-11
      DOI: 10.3390/bios8030084
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 85: Automatic Spot Identification Method for
           High Throughput Surface Plasmon Resonance Imaging Analysis

    • Authors: Zhiyou Wang, Xiaoqing Huang, Zhiqiang Cheng
      First page: 85
      Abstract: An automatic spot identification method is developed for high throughput surface plasmon resonance imaging (SPRi) analysis. As a combination of video accessing, image enhancement, image processing and parallel processing techniques, the method can identify the spots in SPRi images of the microarray from SPRi video data. In demonstrations of the method, SPRi video data of different protein microarrays were processed by the method. Results show that our method can locate spots in the microarray accurately regardless of the microarray pattern, spot-background contrast, light nonuniformity and spotting defects, but also can provide address information of the spots.
      Citation: Biosensors
      PubDate: 2018-09-13
      DOI: 10.3390/bios8030085
      Issue No: Vol. 8, No. 3 (2018)
  • Biosensors, Vol. 8, Pages 86: C-Type Natriuretic Peptide (CNP) Inhibition
           of Interferon-γ-Mediated Gene Expression in Human Endothelial Cells In

    • Authors: Amy Day, Zoe Jameson, Carolyn Hyde, Bigboy Simbi, Robert Fowkes, Charlotte Lawson
      First page: 86
      Abstract: Cardiovascular diseases, including atherosclerosis, now account for more deaths in the Western world than from any other cause. Atherosclerosis has a chronic inflammatory component involving Th1 pro-inflammatory cytokines such as IFN-γ, which is known to induce endothelial cell inflammatory responses. On the other hand CNP, which acts via its receptors to elevate intracellular cGMP, is produced by endothelium and endocardium and is upregulated in atherosclerosis. It is believed to be protective, however its role in vascular inflammation is not well understood. The aim of this study was to investigate the effects of CNP on human endothelial cell inflammatory responses following IFN-γ stimulation. Human umbilical vein endothelial cells were treated with either IFN-γ (10 ng/mL) or CNP (100 nm), or both in combination, followed by analysis by flow cytometry for expression of MHC class I and ICAM-1. IFN-γ significantly increased expression of both molecules, which was significantly inhibited by CNP or the cGMP donor 8-Bromoguanosine 3’,5’-cyclic monophosphate (1 µm). CNP also reduced IFN-γ mediated kynurenine generation by the IFN-γ regulated enzyme indoleamine-2,3-deoxygenase (IDO). We conclude that CNP downmodulates IFN-γ induced pro-inflammatory gene expression in human endothelial cells via a cGMP-mediated pathway. Thus, CNP may have a protective role in vascular inflammation and novel therapeutic strategies for CVD based on upregulation of endothelial CNP expression could reduce chronic EC inflammation.
      Citation: Biosensors
      PubDate: 2018-09-14
      DOI: 10.3390/bios8030086
      Issue No: Vol. 8, No. 3 (2018)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
Home (Search)
Subjects A-Z
Publishers A-Z
Your IP address:
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-