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  Subjects -> CHEMISTRY (Total: 895 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (629 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (48 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (629 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: 28)
ACS Catalysis     Hybrid Journal   (Followers: 44)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 26)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 305)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 24)
Acta Chemica Iasi     Open Access   (Followers: 5)
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: 6)
Advanced Functional Materials     Hybrid Journal   (Followers: 60)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 73)
Advances in Chemical Science     Open Access   (Followers: 18)
Advances in Chemistry     Open Access   (Followers: 23)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
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: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 26)
Advances in Nanoparticles     Open Access   (Followers: 15)
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: 18)
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: 3)
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: 69)
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: 11)
American Mineralogist     Hybrid Journal   (Followers: 16)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 180)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 258)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
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: 13)
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: 24)
Applied Surface Science     Hybrid Journal   (Followers: 32)
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: 379)
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: 22)
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: 140)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 88)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
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: 24)
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: 26)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 11)
Cellulose     Hybrid Journal   (Followers: 9)
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: 206)
Chemical Science     Open Access   (Followers: 27)
Chemical Technology     Open Access   (Followers: 32)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
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: 166)
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: 45)
Chemistry of Materials     Hybrid Journal   (Followers: 268)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 20)
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: 23)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 6)
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: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access  
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: 12)
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: 73)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 4)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)

        1 2 3 4 | Last

Journal Cover
Biosensors
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  [205 journals]
  • 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
           Imaging

    • 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
           Immunosensing

    • 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
           Screening

    • 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
           Nose

    • 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
           Subcutaneously

    • 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
           Prototypes

    • 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 57: Electrochemical (Bio) Sensors for
           Environmental and Food Analyses

    • Authors: Kevin C. Honeychurch, Martina Piano
      First page: 57
      Abstract: In recent years, great progress has been made in the development of sensors and biosensors to meet the demands of environmental and food analysis. In this Special Issue, the state of art and the future trends in the field of environmental and food analyses have been explored. A total of seven papers (three research and four review papers) are included. These are focused on the fabrication and detection of contaminates such as heavy metals, pesticides and food components, including uric acid and 3-hydroxybutyrate. Included in this Issue is a paper dedicated to the experimental determination of the electroactive area of screen-printed electrodes, an important parameter in the development of such sensors.
      Citation: Biosensors
      PubDate: 2018-06-22
      DOI: 10.3390/bios8030057
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 58: Erratum: Khan, N.I.; Maddaus, A.G.; Song, E.
           A Low-Cost Inkjet-Printed Aptamer-Based Electrochemical Biosensor for the
           Selective Detection of Lysozyme. Biosensors 2018, 8, 7

    • Authors: Biosensors Editorial Office Biosensors Editorial Office
      First page: 58
      Abstract: The Biosensors Editorial Office wishes to correct the following errors in this paper [...]
      Citation: Biosensors
      PubDate: 2018-06-22
      DOI: 10.3390/bios8030058
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 59: Nanoscale Biosensors Based on Self-Propelled
           Objects

    • Authors: Beatriz Jurado-Sánchez
      First page: 59
      Abstract: This review provides a comprehensive overview of the latest developments (2016–2018 period) in the nano and micromotors field for biosensing applications. Nano and micromotor designs, functionalization, propulsion modes and transduction mechanism are described. A second important part of the review is devoted to novel in vitro and in vivo biosensing schemes. The potential and future prospect of such moving nanoscale biosensors are given in the conclusions.
      Citation: Biosensors
      PubDate: 2018-06-25
      DOI: 10.3390/bios8030059
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 60: Transfer Learning for Improved Audio-Based
           Human Activity Recognition

    • Authors: Stavros Ntalampiras, Ilyas Potamitis
      First page: 60
      Abstract: Human activities are accompanied by characteristic sound events, the processing of which might provide valuable information for automated human activity recognition. This paper presents a novel approach addressing the case where one or more human activities are associated with limited audio data, resulting in a potentially highly imbalanced dataset. Data augmentation is based on transfer learning; more specifically, the proposed method: (a) identifies the classes which are statistically close to the ones associated with limited data; (b) learns a multiple input, multiple output transformation; and (c) transforms the data of the closest classes so that it can be used for modeling the ones associated with limited data. Furthermore, the proposed framework includes a feature set extracted out of signal representations of diverse domains, i.e., temporal, spectral, and wavelet. Extensive experiments demonstrate the relevance of the proposed data augmentation approach under a variety of generative recognition schemes.
      Citation: Biosensors
      PubDate: 2018-06-25
      DOI: 10.3390/bios8030060
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 61: Application of Biosensors Based on Lipid
           Membranes for the Rapid Detection of Toxins

    • Authors: Georgia-Paraskevi Nikoleli, Dimitrios P. Nikolelis, Christina G. Siontorou, Stephanos Karapetis, Marianna-Thalia Nikolelis
      First page: 61
      Abstract: Lipid assemblies in the form of two dimensional films have been used extensively as biosensing platforms. These films exhibit certain similarities with cell membranes, thus providing a suitable means for the immobilization of proteinaceous moieties and, further, a number of intrinsic signal amplification mechanisms. Their implementation in the detection of toxins yielded reliable and fast detectors for in field analyses of environmental and clinical samples. Some examples are presented herein, including aflatoxin and cholera toxin detection. The conditions and parameters that determine the analytical specifications of the lipid membrane sensors are discussed, advantages and technology bottlenecks are reviewed, and possible further developments are highlighted.
      Citation: Biosensors
      PubDate: 2018-06-26
      DOI: 10.3390/bios8030061
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 62: Surface-Enhanced Raman Scattering
           

    • Authors: Krishna Kant, Sara Abalde-Cela
      First page: 62
      Abstract: Raman scattering and surface-enhanced Raman scattering (SERS) spectroscopy have demonstrated their potential as ultrasensitive detection techniques in the past decades. Specifically, and as a result of the flourishing of nanotechnology, SERS is nowadays one of the most powerful sensing techniques, not only because of the low detection limits that it can achieve, but also for the structural information that it offers and its capability of multiplexing. Similarly, microfluidics technology is having an increased presence not only in fundamental research, but also in the industry. The latter is because of the intrinsic characteristics of microfluidics, being automation, high-throughput, and miniaturization. However, despite miniaturization being an advantage, it comes together with the need to use ultrasensitive techniques for the interrogation of events happening in extremely small volumes. The combination of SERS with microfluidics can overcome bottlenecks present in both technologies. As a consequence, the integration of Raman and SERS in microfluidics is being investigated for the label-free biosensing of relevant research challenges.
      Citation: Biosensors
      PubDate: 2018-06-29
      DOI: 10.3390/bios8030062
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 63: Lectin- and Saccharide-Functionalized
           Nano-Chemiresistor Arrays for Detection and Identification of Pathogenic
           Bacteria Infection

    • Authors: Nuvia M. Saucedo, Yingning Gao, Tung Pham, Ashok Mulchandani
      First page: 63
      Abstract: Improvement upon, and expansion of, diagnostic tools for clinical infections have been increasing in recent years. The simplicity and rapidity of techniques are imperative for their adoption and widespread usage at point-of-care. The fabrication and evaluation of such a device is reported in this work. The use of a small bioreceptor array (based on lectin-carbohydrate binding) resulted in a unique response profile, which has the potential to be used for pathogen identification, as demonstrated by Principal Component Analysis (PCA). The performance of the chemiresistive device was tested with Escherichia coli K12, Enterococcus faecalis, Streptococcus mutans, and Salmonella typhi. The limits of detection, based on concanavalin A (conA) lectin as the bioreceptor, are 4.7 × 103 cfu/mL, 25 cfu/mL, 7.4 × 104 cfu/mL, and 6.3 × 102 cfu/mL. This shows that the detection of pathogenic bacteria is achieved with clinically relevant concentrations. Importantly, responses measured in spiked artificial saliva showed minimal matrix interference. Furthermore, the exploitation of the distinctive outer composition of the bacteria and selectivity of lectin-carbohydrate interactions allowed for the discrimination of bacterial infections from viral infections, which is a current and urgent need for diagnosing common clinical infections.
      Citation: Biosensors
      PubDate: 2018-06-29
      DOI: 10.3390/bios8030063
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 64: The Importance of Multifrequency Impedance
           Sensing of Endothelial Barrier Formation Using ECIS Technology for the
           Generation of a Strong and Durable Paracellular Barrier

    • Authors: Laverne D. Robilliard, Dan T. Kho, Rebecca H. Johnson, Akshata Anchan, Simon J. O’Carroll, Euan Scott Graham
      First page: 64
      Abstract: In this paper, we demonstrate the application of electrical cell-substrate impedance sensing (ECIS) technology for measuring differences in the formation of a strong and durable endothelial barrier model. In addition, we highlight the capacity of ECIS technology to model the parameters of the physical barrier associated with (I) the paracellular space (referred to as Rb) and (II) the basal adhesion of the endothelial cells (α, alpha). Physiologically, both parameters are very important for the correct formation of endothelial barriers. ECIS technology is the only commercially available technology that can measure and model these parameters independently of each other, which is important in the context of ascertaining whether a change in overall barrier resistance (R) occurs because of molecular changes in the paracellular junctional molecules or changes in the basal adhesion molecules. Finally, we show that the temporal changes observed in the paracellular Rb can be associated with changes in specific junctional proteins (CD144, ZO-1, and catenins), which have major roles in governing the overall strength of the junctional communication between neighbouring endothelial cells.
      Citation: Biosensors
      PubDate: 2018-07-04
      DOI: 10.3390/bios8030064
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 65: Transistors for Chemical Monitoring of
           Living Cells

    • Authors: Benoît Piro, Giorgio Mattana, Steeve Reisberg
      First page: 65
      Abstract: We review here the chemical sensors for pH, glucose, lactate, and neurotransmitters, such as acetylcholine or glutamate, made of organic thin-film transistors (OTFTs), including organic electrochemical transistors (OECTs) and electrolyte-gated OFETs (EGOFETs), for the monitoring of cell activity. First, the various chemicals that are produced by living cells and are susceptible to be sensed in-situ in a cell culture medium are reviewed. Then, we discuss the various materials used to make the substrate onto which cells can be grown, as well as the materials used for making the transistors. The main part of this review discusses the up-to-date transistor architectures that have been described for cell monitoring to date.
      Citation: Biosensors
      PubDate: 2018-07-04
      DOI: 10.3390/bios8030065
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 66: Microscale and Nanoscale Biosensors

    • Authors: Beatriz Jurado-Sánchez
      First page: 66
      Abstract: The emerge of nanotechnology along with the success of the microelectronics industry has motivated the miniaturization of biosensors into the nano/microscale. This Special Issue highlights recent advances in microscale and nanoscale biosensors, including self-propelled micromotors: their materials, fabrication, and applications. A total of seven papers (five research and two review papers) are included. Different but related topics are covered, from biosensor design (paper strips and digital microfluidic chips) to integrated configurations that monitor metabolites in cellular environments. The reviews are devoted to protein-based biosensors and moving biosensors based on self-propelled micromotors.
      Citation: Biosensors
      PubDate: 2018-07-06
      DOI: 10.3390/bios8030066
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 67: Autoantibodies as Potential Biomarkers in
           Breast Cancer

    • Authors: Jingyi Qiu, Bailey Keyser, Zuan-Tao Lin, Tianfu Wu
      First page: 67
      Abstract: Breast cancer is a major cause of mortality in women; however, technologies for early stage screening and diagnosis (e.g., mammography and other imaging technologies) are not optimal for the accurate detection of cancer. This creates demand for a more effective diagnostic means to replace or be complementary to existing technologies for early discovery of breast cancer. Cancer neoantigens could reflect tumorigenesis, but they are hardly detectable at the early stage. Autoantibodies, however, are biologically amplified and hence may be measurable early on, making them promising biomarkers to discriminate breast cancer from healthy tissue accurately. In this review, we summarized the recent findings of breast cancer specific antigens and autoantibodies, which may be useful in early detection, disease stratification, and monitoring of treatment responses of breast cancer.
      Citation: Biosensors
      PubDate: 2018-07-13
      DOI: 10.3390/bios8030067
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 68: Clinical Assessment of Dental Implant
           Stability During Follow-Up: What Is Actually Measured, and Perspectives

    • Authors: Elisabetta M. Zanetti, Giulia Pascoletti, Michele Calì, Cristina Bignardi, Giordano Franceschini
      First page: 68
      Abstract: The optimization of loading protocols following dental implant insertion requires setting up patient-specific protocols, customized according to the actual implant osseointegration, measured through quantitative, objective methods. Various devices for the assessment of implant stability as an indirect measure of implant osseointegration have been developed. They are analyzed here, introducing the respective physical models, outlining major advantages and critical aspects, and reporting their clinical performance. A careful discussion of underlying hypotheses is finally reported, as is a suggestion for further development of instrumentation and signal analysis.
      Citation: Biosensors
      PubDate: 2018-07-13
      DOI: 10.3390/bios8030068
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 69: Conjugation of Nanomaterials and Nematic
           Liquid Crystals for Futuristic Applications and Biosensors

    • Authors: Amit Choudhary, Thomas F. George, Guoqiang Li
      First page: 69
      Abstract: The established role of nematic liquid crystals (NLCs) in the recent rapid development of displays has motivated researchers to modulate the electro-optical properties of LCs. Furthermore, adding nanomaterials into NLCs has led to enhancements of the properties of NLCs, like reduced threshold of the operating voltage, variation in pretilt angle, reduced switching time, etc. These enhanced properties, due to interfacial dynamics, are enabling wider applications of NLCs and nanomaterials. The recent literature of nanomaterial-doped NLCs is rich with various kinds of nanomaterials in a variety of NLCs. The light has been focused on the most widely used and studied gold nanoparticles in NLCs. The intrinsic inherent property of easy excitation of surface plasmons polaritons (SPP) is the mediating interaction of NLC electric dipoles and the polarization of charges in the GNP surface. The concepts and methods for the application of metal nanomaterials as dopants in NLCs are discussed for future applications, especially biosensors. The biosensing application of NLCs alone has already been proven in the literature. However, it is always desirable to further enhance the detection efficiency and selectivity, which have been achieved by the conjugation of GNPs and nickel nanoparticles with NLCs and their compatibility with biological materials. This aspect of future application of nanoparticles and NLC makes the point more selective to be included in the present manuscript.
      Citation: Biosensors
      PubDate: 2018-07-14
      DOI: 10.3390/bios8030069
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 70: 3D Carbon Microelectrodes with
           Bio-Functionalized Graphene for Electrochemical Biosensing

    • Authors: Suhith Hemanth, Arnab Halder, Claudia Caviglia, Qijin Chi, Stephan Sylvest Keller
      First page: 70
      Abstract: An enzyme-based electrochemical biosensor has been developed with 3D pyrolytic carbon microelectrodes that have been coated with bio-functionalized reduced graphene oxide (RGO). The 3D carbon working electrode was microfabricated using the pyrolysis of photoresist precursor structures, which were subsequently functionalized with graphene oxide and enzymes. Glucose detection was used to compare the sensor performance achieved with the 3D carbon microelectrodes (3DCMEs) to the 2D electrode configuration. The 3DCMEs provided an approximately two-fold higher sensitivity of 23.56 µA·mM−1·cm−2 compared to 10.19 µA mM−1·cm−2 for 2D carbon in glucose detection using cyclic voltammetry (CV). In amperometric measurements, the sensitivity was more than 4 times higher with 0.39 µA·mM−1·cm−2 for 3D electrodes and 0.09 µA·mM−1·cm−2 for the 2D configuration. The stability analysis of the enzymes on the 3D carbon showed reproducible results over 7 days. The selectivity of the electrode was evaluated with solutions of glucose, uric acid, cholesterol and ascorbic acid, which showed a significantly higher response for glucose.
      Citation: Biosensors
      PubDate: 2018-07-19
      DOI: 10.3390/bios8030070
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 71: Label-Free Monitoring of Human IgG/Anti-IgG
           Recognition Using Bloch Surface Waves on 1D Photonic Crystals

    • Authors: Alberto Sinibaldi, Agostino Occhicone, Peter Munzert, Norbert Danz, Frank Sonntag, Francesco Michelotti
      First page: 71
      Abstract: Optical biosensors based on one-dimensional photonic crystals sustaining Bloch surface waves are proposed to study antibody interactions and perform affinity studies. The presented approach utilizes two types of different antibodies anchored at the sensitive area of a photonic crystal-based biosensor. Such a strategy allows for creating two or more on-chip regions with different biochemical features as well as studying the binding kinetics of biomolecules in real time. In particular, the proposed detection system shows an estimated limit of detection for the target antibody (anti-human IgG) smaller than 0.19 nM (28 ng/mL), corresponding to a minimum surface mass coverage of 10.3 ng/cm2. Moreover, from the binding curves we successfully derived the equilibrium association and dissociation constants (KA = 7.5 × 107 M−1; KD = 13.26 nM) of the human IgG–anti-human IgG interaction.
      Citation: Biosensors
      PubDate: 2018-07-25
      DOI: 10.3390/bios8030071
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 72: Micro-Raman Spectroscopy for Monitoring of
           Deposition Quality of High-k Stack Protective Layer onto Nanowire FET
           Chips for Highly Sensitive miRNA Detection

    • Authors: Kristina A. Malsagova, Tatyana O. Pleshakova, Andrey F. Kozlov, Ivan D. Shumov, Mikhail A. Ilnitskii, Andrew V. Miakonkikh, Vladimir P. Popov, Konstantin V. Rudenko, Alexander V. Glukhov, Igor N. Kupriyanov, Nina D. Ivanova, Alexander E. Rogozhin, Alexander I. Archakov, Yuri D. Ivanov
      First page: 72
      Abstract: Application of micro-Raman spectroscopy for the monitoring of quality of high-k (h-k) dielectric protective layer deposition onto the surface of a nanowire (NW) chip has been demonstrated. A NW chip based on silicon-on-insulator (SOI) structures, protected with a layer of high-k dielectric ((h-k)-SOI-NW chip), has been employed for highly sensitive detection of microRNA (miRNA) associated with oncological diseases. The protective dielectric included a 2-nm-thick Al2O3 surface layer and a 8-nm-thick HfO2 layer, deposited onto a silicon SOI-NW chip. Such a chip had increased time stability upon operation in solution, as compared with an unprotected SOI-NW chip with native oxide. The (h-k)-SOI-NW biosensor has been employed for the detection of DNA oligonucleotide (oDNA), which is a synthetic analogue of miRNA-21 associated with oncological diseases. To provide biospecificity of the detection, the surface of (h-k)-SOI-NW chip was modified with oligonucleotide probe molecules (oDVA probes) complementary to the sequence of the target biomolecule. Concentration sensitivity of the (h-k)-SOI-NW biosensor at the level of DL~10−16 M has been demonstrated.
      Citation: Biosensors
      PubDate: 2018-07-27
      DOI: 10.3390/bios8030072
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 73: Continuous Glucose Monitoring and Exercise
           in Type 1 Diabetes: Past, Present and Future

    • Authors: Shaelyn K. Houlder, Jane E. Yardley
      First page: 73
      Abstract: Prior to the widespread use of continuous glucose monitoring (CGM), knowledge of the effects of exercise in type 1 diabetes (T1D) was limited to the exercise period, with few studies having the budget or capacity to monitor participants overnight. Recently, CGM has become a staple of many exercise studies, allowing researchers to observe the otherwise elusive late post-exercise period. We performed a strategic search using PubMed and Academic Search Complete. Studies were included if they involved adults with T1D performing exercise or physical activity, had a sample size greater than 5, and involved the use of CGM. Upon completion of the search protocol, 26 articles were reviewed for inclusion. While outcomes have been variable, CGM use in exercise studies has allowed the assessment of post-exercise (especially nocturnal) trends for different exercise modalities in individuals with T1D. Sensor accuracy is currently considered adequate for exercise, which has been crucial to developing closed-loop and artificial pancreas systems. Until these systems are perfected, CGM continues to provide information about late post-exercise responses, to assist T1D patients in managing their glucose, and to be useful as a tool for teaching individuals with T1D about exercise.
      Citation: Biosensors
      PubDate: 2018-08-03
      DOI: 10.3390/bios8030073
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 74: Cytokeratins Biosensing Using Tilted Fiber
           Gratings

    • Authors: Médéric Loyez, Jacques Albert, Christophe Caucheteur, Ruddy Wattiez
      First page: 74
      Abstract: Optical fiber gratings have widely proven their applicability in biosensing, especially when they are coupled with antibodies for specific antigen recognition. While this is customarily done with fibers coated by a thin metal film to benefit from plasmonic enhancement, in this paper, we propose to study their intrinsic properties, developing a label-free sensor for the detection of biomarkers in real-time without metal coatings for surface plasmon resonances. We focus on the inner properties of our modal sensor by immobilizing receptors directly on the silica surface, and reporting the sensitivity of bare tilted fiber Bragg gratings (TFBGs) used at near infrared wavelengths. We test different strategies to build our sensing surface against cytokeratins and show that the most reliable functionalization method is the electrostatic adsorption of antibodies on the fiber, allowing a limit of detection reaching 14 pM by following the guided cladding modes near the cut-off area. These results present the biodetection performance that TFBGs bring through their modal properties for different functionalizations and data processing strategies.
      Citation: Biosensors
      PubDate: 2018-08-03
      DOI: 10.3390/bios8030074
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 75: Computational Study of Sensitivity
           Enhancement in Surface Plasmon Resonance (SPR) Biosensors by Using the
           Inclusion of the Core-Shell for Biomaterial Sample Detection

    • Authors: Widayanti, Kamsul Abraha, Agung Bambang Setio Utomo
      First page: 75
      Abstract: A theoretical analysis and computational study of biomaterial sample detection with surface plasmon resonance (SPR) phenomenon spectroscopy are presented in this work with the objective of achieving more sensitive detection. In this paper, a Fe3O4@Au core-shell, a nanocomposite spherical nanoparticle consisting of a spherical Fe3O4 core covered by an Au shell, was used as an active material for biomaterial sample detection, such as for blood plasma, haemoglobin (Hb) cytoplasm and lecithin, with a wavelength of 632.8 nm. We present the detection amplification technique through an attenuated total reflection (ATR) spectrum in the Kretschmann configuration. The system consists of a four-layer material, i.e., prism/Ag/Fe3O4@Au + biomaterial sample/air. The effective permittivity determination of the core-shell nanoparticle (Fe3O4@Au) and the composite (Fe3O4@Au + biomaterial sample) was done by applying the effective medium theory approximation, and the calculation of the reflectivity was carried out by varying the size of the core-shell, volume fraction and biomaterial sample. In this model, the refractive index (RI) of the BK7 prism is 1.51; the RI of the Ag thin film is 0.13455 + 3.98651i with a thickness of 40 nm; and the RI of the composite is varied depending on the size of the nanoparticle core-shell and the RI of the biomaterial samples. Our results show that by varying the sizes of the core-shell, volume fraction and the RIs of the biomaterial samples, the dip in the reflectivity (ATR) spectrum is shifted to the larger angle of incident light, and the addition of a core-shell in the conventional SPR-based biosensor leads to the enhancement of the SPR biosensor sensitivity. For a core-shell with a radius a = 2.5 nm, the sensitivity increased by 10% for blood plasma detection, 47.72% for Hb cytoplasm detection and by 22.08% for lecithin detection compared to the sensitivity of the conventional SPR-based biosensor without core-shell addition.
      Citation: Biosensors
      PubDate: 2018-08-07
      DOI: 10.3390/bios8030075
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 76: Synergistic Integration of Laboratory and
           Numerical Approaches in Studies of the Biomechanics of Diseased Red Blood
           Cells

    • Authors: He Li, Dimitrios P. Papageorgiou, Hung-Yu Chang, Lu Lu, Jun Yang, Yixiang Deng
      First page: 76
      Abstract: In red blood cell (RBC) disorders, such as sickle cell disease, hereditary spherocytosis, and diabetes, alterations to the size and shape of RBCs due to either mutations of RBC proteins or changes to the extracellular environment, lead to compromised cell deformability, impaired cell stability, and increased propensity to aggregate. Numerous laboratory approaches have been implemented to elucidate the pathogenesis of RBC disorders. Concurrently, computational RBC models have been developed to simulate the dynamics of RBCs under physiological and pathological conditions. In this work, we review recent laboratory and computational studies of disordered RBCs. Distinguished from previous reviews, we emphasize how experimental techniques and computational modeling can be synergically integrated to improve the understanding of the pathophysiology of hematological disorders.
      Citation: Biosensors
      PubDate: 2018-08-10
      DOI: 10.3390/bios8030076
      Issue No: Vol. 8, No. 3 (2018)
       
  • Biosensors, Vol. 8, Pages 77: Development of MoSe2 Nano-Urchins as a
           Sensing Platform for a Selective Bio-Capturing of Escherichia. coli Shiga
           Toxin DNA

    • Authors: Jagriti Narang, Annu Mishra, Roberto Pilloton, Alekhya VV, Shikha Wadhwa, Chandra Shekhar Pundir, Manika Khanuja
      First page: 77
      Abstract: The present study was aimed to develop “fluorine doped” tin oxide glass electrode with a MoSe2 nano-urchin based electrochemical biosensor for detection of Escherichia. coli Shiga toxin DNA. The study comprises two conductive electrodes, and the working electrodes were drop deposited using MoSe2 nano-urchin, and DNA sequences specific to Shiga toxin Escherichia. coli. Morphological characterizations were performed using Fourier transforms infrared spectrophotometer; X-ray diffraction technique and scanning electron microscopy. All measurements were done using methylene blue as an electrochemical indicator. The proposed electrochemical geno-sensor showed good linear detection range of 1 fM–100 μM with a low detection limit of 1 fM where the current response increased linearly with Escherichia. coli Shiga toxin dsDNA concentration with R2 = 0.99. Additionally, the real sample was spiked with the dsDNA that shows insignificant interference. The results revealed that the developed sensing platform significantly improved the sensitivity and can provide a promising platform for effective detection of biomolecules using minute samples due to its stability and sensitivity.
      Citation: Biosensors
      PubDate: 2018-08-14
      DOI: 10.3390/bios8030077
      Issue No: Vol. 8, No. 3 (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
           Antibiotics

    • 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
           Vitro

    • 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)
       
  • Biosensors, Vol. 8, Pages 32: Development of a β-Lactoglobulin Sensor
           Based on SPR for Milk Allergens Detection

    • Authors: Jon Ashley, Roberta D’Aurelio, Monika Piekarska, Jeff Temblay, Mike Pleasants, Linda Trinh, Thomas Rodgers, Ibtisam Tothill
      First page: 32
      Abstract: A sensitive and label-free surface plasmon resonance (SPR) based sensor was developed in this work for the detection of milk allergens. β-lactoglobulin (BLG) protein was used as the biomarker for cow milk detection. This is to be used directly in final rinse samples of cleaning in-place (CIP) systems of food manufacturers. The affinity assay was optimised and characterised before a standard curve was performed in pure buffer conditions, giving a detection limit of 0.164 µg mL−1 as a direct binding assay. The detection limit can be further enhanced through the use of a sandwich assay and amplification with nanomaterials. However, this was not required here, as the detection limit achieved exceeded the required allergen detection levels of 2 µg mL−1 for β-lactoglobulin. The binding affinities of the polyclonal antibody for BLG, expressed by the dissociation constant (KD), were equal to 2.59 × 10−9 M. The developed SPR-based sensor offers several advantages in terms of label-free detection, real-time measurements, potential on-line system and superior sensitivity when compared to ELISA-based techniques. The method is novel for this application and could be applied to wider food allergen risk management decision(s) in food manufacturing.
      Citation: Biosensors
      PubDate: 2018-03-27
      DOI: 10.3390/bios8020032
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 33: Smart Garment Fabrics to Enable Non-Contact
           Opto-Physiological Monitoring

    • Authors: Dmitry Iakovlev, Sijung Hu, Harnani Hassan, Vincent Dwyer, Roya Ashayer-Soltani, Chris Hunt, Jinsong Shen
      First page: 33
      Abstract: Imaging photoplethysmography (iPPG) is an emerging technology used to assess microcirculation and cardiovascular signs by collecting backscattered light from illuminated tissue using optical imaging sensors. The aim of this study was to study how effective smart garment fabrics could be capturing physiological signs in a non-contact mode. The present work demonstrates a feasible approach of, instead of using conventional high-power illumination sources, integrating a grid of surface-mounted light emitting diodes (LEDs) into cotton fabric to spotlight the region of interest (ROI). The green and the red LEDs (525 and 660 nm) placed on a small cotton substrate were used to locally illuminate palm skin in a dual-wavelength iPPG setup, where the backscattered light is transmitted to a remote image sensor through the garment fabric. The results show that the illuminations from both wavelength LEDs can be used to extract heart rate (HR) reaching an accuracy of 90% compared to a contact PPG probe. Stretching the fabric over the skin surface alters the morphology of iPPG signals, demonstrating a significantly higher pulsatile amplitude in both channels of green and red illuminations. The skin compression by the fabric could be potentially utilised to enhance the penetration of illumination into cutaneous microvascular beds. The outcome could lead a new avenue of non-contact opto-physiological monitoring and assessment with functional garment fabrics.
      Citation: Biosensors
      PubDate: 2018-03-29
      DOI: 10.3390/bios8020033
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 34: Label-Free Electrochemical Immunoassay for
           C-Reactive Protein

    • Authors: Madasamy Thangamuthu, Christian Santschi, Olivier J. F. Martin
      First page: 34
      Abstract: C-reactive protein (CRP) is one of the most expressed proteins in blood during acute phase inflammation, and its minute level increase has also been recognized for the clinical diagnosis of cardio vascular diseases. Unfortunately, the available commercial immunoassays are labour intensive, require large sample volumes, and have practical limitations, such as low stability and high production costs. Hence, we have developed a simple, cost effective, and label-free electrochemical immunoassay for the measurement of CRP in a drop of serum sample using an immunosensor strip made up of a screen printed carbon electrode (SPE) modified with anti-CRP functionalized gold nanoparticles (AuNPs). The measurement relies on the decrease of the oxidation current of the redox indicator Fe3+/Fe2+, resulting from the immunoreaction between CRP and anti-CRP. Under optimal conditions, the present immunoassay measures CRP in a linear range from 0.4–200 nM (0.047–23.6 µg mL−1), with a detection limit of 0.15 nM (17 ng mL−1, S/N = 3) and sensitivity of 90.7 nA nM−1, in addition to a good reproducibility and storage stability. The analytical applicability of the presented immunoassay is verified by CRP measurements in human blood serum samples. This work provides the basis for a low-priced, safe, and easy-to-use point-of-care immunosensor assay to measure CRP at clinically relevant concentrations.
      Citation: Biosensors
      PubDate: 2018-03-30
      DOI: 10.3390/bios8020034
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 35: Sensors Based on Bio and Biomimetic
           Receptors in Medical Diagnostic, Environment, and Food Analysis

    • Authors: Alisa Kozitsina, Tatiana Svalova, Natalia Malysheva, Andrei Okhokhonin, Marina Vidrevich, Khiena Brainina
      First page: 35
      Abstract: Analytical chemistry is now developing mainly in two areas: automation and the creation of complexes that allow, on the one hand, for simultaneously analyzing a large number of samples without the participation of an operator, and on the other, the development of portable miniature devices for personalized medicine and the monitoring of a human habitat. The sensor devices, the great majority of which are biosensors and chemical sensors, perform the role of the latter. That last line is considered in the proposed review. Attention is paid to transducers, receptors, techniques of immobilization of the receptor layer on the transducer surface, processes of signal generation and detection, and methods for increasing sensitivity and accuracy. The features of sensors based on synthetic receptors and additional components (aptamers, molecular imprinted polymers, biomimetics) are discussed. Examples of bio- and chemical sensors’ application are given. Miniaturization paths, new power supply means, and wearable and printed sensors are described. Progress in this area opens a revolutionary era in the development of methods of on-site and in-situ monitoring, that is, paving the way from the “test-tube to the smartphone”.
      Citation: Biosensors
      PubDate: 2018-04-01
      DOI: 10.3390/bios8020035
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 36: The Use of a Polyphenoloxidase Biosensor
           Obtained from the Fruit of Jurubeba (Solanum paniculatum L.) in the
           Determination of Paracetamol and Other Phenolic Drugs

    • Authors: Rafael Antunes, Luane Garcia, Vernon Somerset, Eric Gil, Flavio Lopes
      First page: 36
      Abstract: The vegetable kingdom is a wide source of a diverse variety of enzymes with broad biotechnological applications. Among the main classes of plant enzymes, the polyphenol oxidases, which convert phenolic compounds to the related quinones, have been successfully used for biosensor development. The oxidation products from such enzymes can be electrochemically reduced, and the sensing is easily achieved by amperometric transducers. In this work, the polyphenoloxidases were extracted from jurubeba (Solanum paniculatum L.) fruits, and the extract was used to construct a carbon paste-based biosensor for pharmaceutical analysis and applications. The assay optimization was performed using a 0.1 mM catechol probe, taking into account the amount of enzymatic extract (50 or 200 μL) and the optimum pH (3.0 to 9.0) as well as some electrochemical differential pulse voltammetric (DPV) parameters (e.g., pulse amplitude, pulse range, pulse width, scan rate). Under optimized conditions, the biosensor was evaluated for the quantitative determination of acetaminophen, acetylsalicylic acid, methyldopa, and ascorbic acid. The best performance was obtained for acetaminophen, which responded linearly in the range between 5 and 245 μM (R = 0.9994), presenting a limit of detection of 3 μM and suitable repeatability ranging between 1.52% and 1.74% relative standard deviation (RSD).
      Citation: Biosensors
      PubDate: 2018-04-02
      DOI: 10.3390/bios8020036
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 37: Functionalized Thick Film Impedance Sensors
           for Use in In Vitro Cell Culture

    • Authors: Heike Bartsch, Martin Baca, Uta Fernekorn, Jens Müller, Andreas Schober, Hartmut Witte
      First page: 37
      Abstract: Multi-electrode arrays find application in electrophysiological recordings. The quality of the captured signals depends on the interfacial contact between electrogenic cells and the electronic system. Therefore, it requires reliable low-impedance electrodes. Low-temperature cofired ceramic technology offers a suitable platform for rapid prototyping of biological reactors and can provide both stable fluid supply and integrated bio-hardware interfaces for recordings in electrogenic cell cultures. The 3D assembly of thick film gold electrodes in in vitro bio-reactors has been demonstrated for neuronal recordings. However, especially when dimensions become small, their performance varies strongly. This work investigates the influence of different coatings on thick film gold electrodes with regard to their influence on impedance behavior. PEDOT:PSS layer, titanium oxynitride and laminin coatings are deposited on LTCC gold electrodes using different 2D and 3D MEA chip designs. Their impedance characteristics are compared and discussed. Titanium oxynitride layers emerged as suitable functionalization. Small 86-µm-electrodes have a serial resistance Rs of 32 kOhm and serial capacitance Cs of 4.1 pF at 1 kHz. Thick film gold electrodes with such coatings are thus qualified for signal recording in 3-dimensional in vitro cell cultures.
      Citation: Biosensors
      PubDate: 2018-04-05
      DOI: 10.3390/bios8020037
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 38: Raman Spectroscopic and Microscopic Analysis
           for Monitoring Renal Osteodystrophy Signatures

    • Authors: John Ciubuc, Marian Manciu, Avudaiappan Maran, Michael Yaszemski, Emma Sundin, Kevin Bennet, Felicia Manciu
      First page: 38
      Abstract: Defining the pathogenesis of renal osteodystrophy (ROD) and its treatment efficacy are difficult, since many factors potentially affect bone quality. In this study, confocal Raman microscopy and parallel statistical analysis were used to identify differences in bone composition between healthy and ROD bone tissues through direct visualization of three main compositional parametric ratios, namely, calcium content, mineral-to-matrix, and carbonate-to-matrix. Besides the substantially lower values found in ROD specimens for these representative ratios, an obvious accumulation of phenylalanine is Raman spectroscopically observed for the first time in ROD samples and reported here. Thus, elevated phenylalanine could also be considered as an indicator of the disease. Since the image results are based on tens of thousands of spectra per sample, not only are the average ratios statistically significantly different for normal and ROD bone, but the method is clearly powerful in distinguishing between the two types of samples. Furthermore, the statistical outcomes demonstrate that only a relatively small number of spectra need to be recorded in order to classify the samples. This work thus opens the possibility of future development of in vivo Raman sensors for assessment of bone structure, remodeling, and mineralization, where different biomarkers are simultaneously detected with unprecedented accuracy.
      Citation: Biosensors
      PubDate: 2018-04-08
      DOI: 10.3390/bios8020038
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 39: Metabolism-Driven High-Throughput Cancer
           Identification with GLUT5-Specific Molecular Probes

    • Authors: Srinivas Kannan, Vagarshak Begoyan, Joseph Fedie, Shuai Xia, Łukasz Weseliński, Marina Tanasova, Smitha Rao
      First page: 39
      Abstract: Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and premalignant cells leading to a novel detection approach. The vastly different uptake kinetics of the analogs yields two unique signatures for each cell type. We used normal breast cells MCF10A, adenocarcinoma cells MCF7, and premalignant cells MCF10AneoT, with hepatocellular carcinoma cells HepG2 as the negative control. Our data indicated that MCF10AneoT and MCF7 cells had an observable difference in response to only one of the analogs. The response, observed as fluorescence intensity, leads to a two-point assessment of the cells in any sample. Since the treatment time is 10 min, there is potential for use in rapid on-site high-throughput diagnostics.
      Citation: Biosensors
      PubDate: 2018-04-10
      DOI: 10.3390/bios8020039
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 40: S-Layer Protein-Based Biosensors

    • Authors: Bernhard Schuster
      First page: 40
      Abstract: The present paper highlights the application of bacterial surface (S-) layer proteins as versatile components for the fabrication of biosensors. One technologically relevant feature of S-layer proteins is their ability to self-assemble on many surfaces and interfaces to form a crystalline two-dimensional (2D) protein lattice. The S-layer lattice on the surface of a biosensor becomes part of the interface architecture linking the bioreceptor to the transducer interface, which may cause signal amplification. The S-layer lattice as ultrathin, highly porous structure with functional groups in a well-defined special distribution and orientation and an overall anti-fouling characteristics can significantly raise the limit in terms of variety and the ease of bioreceptor immobilization, compactness of bioreceptor molecule arrangement, sensitivity, specificity, and detection limit for many types of biosensors. The present paper discusses and summarizes examples for the successful implementation of S-layer lattices on biosensor surfaces in order to give a comprehensive overview on the application potential of these bioinspired S-layer protein-based biosensors.
      Citation: Biosensors
      PubDate: 2018-04-11
      DOI: 10.3390/bios8020040
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 41: Olfactory Dysfunction as a Global Biomarker
           for Sniffing out Alzheimer’s Disease: A Meta-Analysis

    • Authors: Alisha Kotecha, Angelo Corrêa, Kim Fisher, Jo Rushworth
      First page: 41
      Abstract: Cases of Alzheimer’s disease (AD) are rising exponentially due to increasing global life expectancy. There are approximately 50 million sufferers worldwide, with prevalence rising most rapidly in low-income countries such as Africa and Asia. There is currently no definite diagnosis of AD until after death, thus an early biomarker for AD is urgently required in order to administer timelier and more effective interventions. Olfactory dysfunction (problems with the sense of smell) is one of the earliest, preclinical symptoms observed in AD. Olfaction is a promising early biomarker for use worldwide as it is easy, cheap to measure, and not reliant on specialist clinicians or laboratory analysis. We carried out a meta-analysis to determine the credibility of olfaction in diagnosing AD in the preclinical stages, by comparing olfaction in healthy controls against AD patients and patients with mild cognitive impairment (MCI). Data from 10 articles were subjected to two comparative meta-analyses. In the case of AD, the results illustrated that the overall magnitude of effect size was more apparent, d = −1.63, 95% CI [−1.95, −1.31], in comparison to that of MCI, d = −0.81, 95% CI [−1.08, −0.55]. This shows that olfaction worsens progressively as patients progress from MCI to AD, highlighting the potential for olfactory dysfunction to identify AD in the preclinical stages prior to MCI.
      Citation: Biosensors
      PubDate: 2018-04-13
      DOI: 10.3390/bios8020041
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 42: Laser Scribed Graphene Biosensor for
           Detection of Biogenic Amines in Food Samples Using Locally Sourced
           Materials

    • Authors: Diana C. Vanegas, Laksmi Patiño, Connie Mendez, Daniela Alves de Oliveira, Alba M. Torres, Carmen L. Gomes, Eric S. McLamore
      First page: 42
      Abstract: In foods, high levels of biogenic amines (BA) are the result of microbial metabolism that could be affected by temperatures and storage conditions. Thus, the level of BA is commonly used as an indicator of food safety and quality. This manuscript outlines the development of laser scribed graphene electrodes, with locally sourced materials, for reagent-free food safety biosensing. To fabricate the biosensors, the graphene surface was functionalized with copper microparticles and diamine oxidase, purchased from a local supermarket; and then compared to biosensors fabricated with analytical grade materials. The amperometric biosensor exhibits good electrochemical performance, with an average histamine sensitivity of 23.3 µA/mM, a lower detection limit of 11.6 µM, and a response time of 7.3 s, showing similar performance to biosensors constructed from analytical grade materials. We demonstrated the application of the biosensor by testing total BA concentration in fish paste samples subjected to fermentation with lactic acid bacteria. Biogenic amines concentrations prior to lactic acid fermentation were below the detection limit of the biosensor, while concentration after fermentation was 19.24 ± 8.21 mg histamine/kg, confirming that the sensor was selective in a complex food matrix. The low-cost, rapid, and accurate device is a promising tool for biogenic amine estimation in food samples, particularly in situations where standard laboratory techniques are unavailable, or are cost prohibitive. This biosensor can be used for screening food samples, potentially limiting food waste, while reducing chances of foodborne outbreaks.
      Citation: Biosensors
      PubDate: 2018-04-24
      DOI: 10.3390/bios8020042
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 43: Continuous Glucose Monitoring in
           Resource-Constrained Settings for Hypoglycaemia Detection: Looking at the
           Problem from the Other Side of the Coin

    • Authors: Rubao Bila, Rosauro Varo, Lola Madrid, Antonio Sitoe, Quique Bassat
      First page: 43
      Abstract: The appearance, over a decade ago, of continuous glucose monitoring (CGM) devices has triggered a patient-centred revolution in the control and management of diabetes mellitus and other metabolic conditions, improving the patient’s glycaemic control and quality of life. Such devices, the use of which remains typically restricted to high-income countries on account of their elevated costs, at present show very limited implantation in resource-constrained settings, where many other urgent health priorities beyond diabetes prevention and management still need to be resolved. In this commentary, we argue that such devices could have an additional utility in low-income settings, whereby they could be selectively used among severely ill children admitted to hospital for closer monitoring of paediatric hypoglycaemia, a life-threatening condition often complicating severe cases of malaria, malnutrition, and other common paediatric conditions.
      Citation: Biosensors
      PubDate: 2018-04-25
      DOI: 10.3390/bios8020043
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 44: Sensor Access to the Cellular
           Microenvironment Using the Sensing Cell Culture Flask

    • Authors: Jochen Kieninger, Yaara Tamari, Barbara Enderle, Gerhard Jobst, Joe Sandvik, Erik Pettersen, Gerald Urban
      First page: 44
      Abstract: The Sensing Cell Culture Flask (SCCF) is a cell culture monitoring system accessing the cellular microenvironment in 2D cell culture using electrochemical microsensors. The system is based on microfabricated sensor chips embedded in standard cell culture flasks. Ideally, the sensor chips could be equipped with any electrochemical sensor. Its transparency allows optical inspection of the cells during measurement. The surface of the sensor chip is in-plane with the flask surface allowing undisturbed cell growth on the sensor chip. A custom developed rack system allows easy usage of multiple flasks in parallel within an incubator. The presented data demonstrates the application of the SCCF with brain tumor (T98G) and breast cancer (T-47D) cells. Amperometric oxygen sensors were used to monitor cellular respiration with different incubation conditions. Cellular acidification was accessed with potentiometric pH sensors using electrodeposited iridium oxide films. The system itself provides the foundation for electrochemical monitoring systems in 3D cell culture.
      Citation: Biosensors
      PubDate: 2018-04-26
      DOI: 10.3390/bios8020044
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 45: Droplet Velocity Measurement Based on
           Dielectric Layer Thickness Variation Using Digital Microfluidic Devices

    • Authors: Siti Noor Idora Syafinaz Zulkepli, Nor Hisham Hamid, Vineeta Shukla
      First page: 45
      Abstract: In recent years, the number of interdisciplinary research works related to the development of miniaturized systems with integrated chemical and biological analyses is increasing. Digital microfluidic biochips (DMFBs) are one kind of miniaturized systems designed for conducting inexpensive, fast, convenient and reliable biochemical assay procedures focusing on basic scientific research and medical diagnostics. The role of a dielectric layer in the digital microfluidic biochips is prominent as it helps in actuating microliter droplets based on the electrowetting-on-dielectric (EWOD) technique. The advantages of using three different material layers of dielectric such as parafilm, polytetrafluoroethylene (PTFE) and ethylene tetrafluoroethylene (ETFE) were reported in the current work. A simple fabrication process of a digital microfluidic device was performed and good results were obtained. The threshold of the actuation voltage was determined for all dielectric materials of varying thicknesses. Additionally, the OpenDrop device was tested by utilizing a single-plate system to transport microliter droplets for a bioassay operation. With the newly proposed fabrication methods, these dielectric materials showed changes in contact angle and droplet velocity when the actuation voltage was applied. The threshold actuation voltage for the dielectric layers of 10–13 μm was 190 V for the open plate DMFBs.
      Citation: Biosensors
      PubDate: 2018-05-08
      DOI: 10.3390/bios8020045
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 46: In Vitro and In Vivo SERS Biosensing for
           Disease Diagnosis

    • Authors: T. Joshua Moore, Amber S. Moody, Taylor D. Payne, Grace M. Sarabia, Alyssa R. Daniel, Bhavya Sharma
      First page: 46
      Abstract: For many disease states, positive outcomes are directly linked to early diagnosis, where therapeutic intervention would be most effective. Recently, trends in disease diagnosis have focused on the development of label-free sensing techniques that are sensitive to low analyte concentrations found in the physiological environment. Surface-enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy that allows for label-free, highly sensitive, and selective detection of analytes through the amplification of localized electric fields on the surface of a plasmonic material when excited with monochromatic light. This results in enhancement of the Raman scattering signal, which allows for the detection of low concentration analytes, giving rise to the use of SERS as a diagnostic tool for disease. Here, we present a review of recent developments in the field of in vivo and in vitro SERS biosensing for a range of disease states including neurological disease, diabetes, cardiovascular disease, cancer, and viral disease.
      Citation: Biosensors
      PubDate: 2018-05-11
      DOI: 10.3390/bios8020046
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 47: Development of a Polyphenol Oxidase
           Biosensor from Jenipapo Fruit Extract (Genipa americana L.) and
           Determination of Phenolic Compounds in Textile Industrial Effluents

    • Authors: Rafael Antunes, Denes Ferraz, Luane Garcia, Douglas Thomaz, Rafael Luque, Germán Lobón, Eric Gil, Flávio Lopes
      First page: 47
      Abstract: In this work, an innovative polyphenol oxidase biosensor was developed from Jenipapo (Genipa americana L.) fruit and used to assess phenolic compounds in industrial effluent samples obtained from a textile industry located in Jaraguá-GO, Brasil. The biosensor was prepared and optimized according to: the proportion of crude vegetal extract, pH and overall voltammetric parameters for differential pulse voltammetry. The calibration curve presented a linear interval from 10 to 310 µM (r2 = 0.9982) and a limit of detection of 7 µM. Biosensor stability was evaluated throughout 15 days, and it exhibited 88.22% of the initial response. The amount of catechol standard recovered post analysis varied between 87.50% and 96.00%. Moreover, the biosensor was able to detect phenolic compounds in a real sample, and the results were in accordance with standard spectrophotometric assays. Therefore, the innovatively-designed biosensor hereby proposed is a promising tool for phenolic compound detection and quantification when environmental contaminants are concerned.
      Citation: Biosensors
      PubDate: 2018-05-15
      DOI: 10.3390/bios8020047
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 48: Breathing Pattern Interpretation as an
           Alternative and Effective Voice Communication Solution

    • Authors: Yasmin Elsahar, Kaddour Bouazza-Marouf, David Kerr, Atul Gaur, Vipul Kaushik, Sijung Hu
      First page: 48
      Abstract: Augmentative and alternative communication (AAC) systems tend to rely on the interpretation of purposeful gestures for interaction. Existing AAC methods could be cumbersome and limit the solutions in terms of versatility. The study aims to interpret breathing patterns (BPs) to converse with the outside world by means of a unidirectional microphone and researches breathing-pattern interpretation (BPI) to encode messages in an interactive manner with minimal training. We present BP processing work with (1) output synthesized machine-spoken words (SMSW) along with single-channel Weiner filtering (WF) for signal de-noising, and (2) k-nearest neighbor (k-NN) classification of BPs associated with embedded dynamic time warping (DTW). An approved protocol to collect analogue modulated BP sets belonging to 4 distinct classes with 10 training BPs per class and 5 live BPs per class was implemented with 23 healthy subjects. An 86% accuracy of k-NN classification was obtained with decreasing error rates of 17%, 14%, and 11% for the live classifications of classes 2, 3, and 4, respectively. The results express a systematic reliability of 89% with increased familiarity. The outcomes from the current AAC setup recommend a durable engineering solution directly beneficial to the sufferers.
      Citation: Biosensors
      PubDate: 2018-05-15
      DOI: 10.3390/bios8020048
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 49: Consistency of Continuous Ambulatory
           Interstitial Glucose Monitoring Sensors

    • Authors: Pei T. Wu, David E. Segovia, Cathy C. Lee, Kim-Lien Nguyen
      First page: 49
      Abstract: Aims: The abdominal region is the most common location for continuous glucose monitor (CGM) sensor insertion. However, a paucity of post-marketing data is available to demonstrate intra-individual consistency of CGM readings at different abdominal insertion sites. Methods: Healthy adults (fasting glucose (FG) < 5.5 mmol/L; BMI < 30 kg/m2) were recruited and a CGM sensor was placed on each side of the abdomen. Postprandial and continuous 48-h interstitial glucose levels were analyzed. Results: There was no significant difference in the 3-h postprandial glucose (PPG) level derived from the left versus right CGM, which remained non-significant after adjusting for waist circumference or FG. Among the glucose levels recorded over 48-h, values on the left site were greater in 3.6% of the data points (p < 0.05). After adjusting for waist circumference, only 0.5% of the glucose values remained significantly greater on the left (p < 0.05). When adjusted for FG, similar results were observed. For both PPG and 48-h readings, the mean absolute relative difference was not significant between the two abdominal sites. Conclusions: CGM-derived glucose measures were highly consistent between the left and right abdomen during both the postprandial and post-absorptive periods.
      Citation: Biosensors
      PubDate: 2018-05-16
      DOI: 10.3390/bios8020049
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 50: Limits to the Evaluation of the Accuracy of
           Continuous Glucose Monitoring Systems by Clinical Trials

    • Authors: Patrick Schrangl, Florian Reiterer, Lutz Heinemann, Guido Freckmann, Luigi del Re
      First page: 50
      Abstract: Systems for continuous glucose monitoring (CGM) are evolving quickly, and the data obtained are expected to become the basis for clinical decisions for many patients with diabetes in the near future. However, this requires that their analytical accuracy is sufficient. This accuracy is usually determined with clinical studies by comparing the data obtained by the given CGM system with blood glucose (BG) point measurements made with a so-called reference method. The latter is assumed to indicate the correct value of the target quantity. Unfortunately, due to the nature of the clinical trials and the approach used, such a comparison is subject to several effects which may lead to misleading results. While some reasons for the differences between the values obtained with CGM and BG point measurements are relatively well-known (e.g., measurement in different body compartments), others related to the clinical study protocols are less visible, but also quite important. In this review, we present a general picture of the topic as well as tools which allow to correct or at least to estimate the uncertainty of measures of CGM system performance.
      Citation: Biosensors
      PubDate: 2018-05-18
      DOI: 10.3390/bios8020050
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 51: New Carrier Made from Glass Nanofibres for
           the Colorimetric Biosensor of Cholinesterase Inhibitors

    • Authors: Lukáš Matějovský, Vladimír Pitschmann
      First page: 51
      Abstract: Cholinesterase inhibitors are widely used as pesticides in agriculture, but also form a group of organophosphates known as nerve chemical warfare agents. This calls for close attention regarding their detection, including the use of various biosensors. One such biosensor made in the Czech Republic is the Detehit, which is based on a cholinesterase reaction that is assessed using a colour indicator—the Ellman’s reagent—which is anchored on cellulose filter paper together with the substrate. With the use of this biosensor, detection is simple, quick, and sensitive. However, its disadvantage is that a less pronounced yellow discoloration occurs, especially under difficult light conditions. As a possible solution, a new indicator/substrate carrier has been designed. It is made of glass nanofibres, so the physical characteristics of the carrier positively influence reaction conditions, and as a result improve the colour response of the biosensor. The authors present and discuss some of the results of the study of this carrier under various experimental conditions. These findings have been used for the development of a modified Detehit biosensor.
      Citation: Biosensors
      PubDate: 2018-05-30
      DOI: 10.3390/bios8020051
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 52: Label-Free Bioanalyte Detection from
           Nanometer to Micrometer Dimensions—Molecular Imprinting and QCMs †

    • Authors: Adnan Mujahid, Ghulam Mustafa, Franz L. Dickert
      First page: 52
      Abstract: Modern diagnostic tools and immunoassay protocols urges direct analyte recognition based on its intrinsic behavior without using any labeling indicator. This not only improves the detection reliability, but also reduces sample preparation time and complexity involved during labeling step. Label-free biosensor devices are capable of monitoring analyte physiochemical properties such as binding sensitivity and selectivity, affinity constants and other dynamics of molecular recognition. The interface of a typical biosensor could range from natural antibodies to synthetic receptors for example molecular imprinted polymers (MIPs). The foremost advantages of using MIPs are their high binding selectivity comparable to natural antibodies, straightforward synthesis in short time, high thermal/chemical stability and compatibility with different transducers. Quartz crystal microbalance (QCM) resonators are leading acoustic devices that are extensively used for mass-sensitive measurements. Highlight features of QCM devices include low cost fabrication, room temperature operation, and most importantly ability to monitor extremely low mass shifts, thus potentially a universal transducer. The combination of MIPs with quartz QCM has turned out as a prominent sensing system for label-free recognition of diverse bioanalytes. In this article, we shall encompass the potential applications of MIP-QCM sensors exclusively label-free recognition of bacteria and virus species as representative micro and nanosized bioanalytes.
      Citation: Biosensors
      PubDate: 2018-06-01
      DOI: 10.3390/bios8020052
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 53: Determination of the Electrochemical Area of
           Screen-Printed Electrochemical Sensing Platforms

    • Authors: Alejandro García-Miranda Ferrari, Christopher W. Foster, Peter J. Kelly, Dale A. C. Brownson, Craig E. Banks
      First page: 53
      Abstract: Screen-printed electrochemical sensing platforms, due to their scales of economy and high reproducibility, can provide a useful approach to translate laboratory-based electrochemistry into the field. An important factor when utilising screen-printed electrodes (SPEs) is the determination of their real electrochemical surface area, which allows for the benchmarking of these SPEs and is an important parameter in quality control. In this paper, we consider the use of cyclic voltammetry and chronocoulometry to allow for the determination of the real electrochemical area of screen-printed electrochemical sensing platforms, highlighting to experimentalists the various parameters that need to be diligently considered and controlled in order to obtain useful measurements of the real electroactive area.
      Citation: Biosensors
      PubDate: 2018-06-08
      DOI: 10.3390/bios8020053
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 54: Aptamer-Based Biosensors for Antibiotic
           Detection: A Review

    • Authors: Asol Mehlhorn, Parvaneh Rahimi, Yvonne Joseph
      First page: 54
      Abstract: Antibiotic resistance and, accordingly, their pollution because of uncontrolled usage has emerged as a serious problem in recent years. Hence, there is an increased demand to develop robust, easy, and sensitive methods for rapid evaluation of antibiotics and their residues. Among different analytical methods, the aptamer-based biosensors (aptasensors) have attracted considerable attention because of good selectivity, specificity, and sensitivity. This review gives an overview about recently-developed aptasensors for antibiotic detection. The use of various aptamer assays to determine different groups of antibiotics, like β-lactams, aminoglycosides, anthracyclines, chloramphenicol, (fluoro)quinolones, lincosamide, tetracyclines, and sulfonamides are presented in this paper.
      Citation: Biosensors
      PubDate: 2018-06-11
      DOI: 10.3390/bios8020054
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 55: Biosensors for Non-Invasive Detection of
           Celiac Disease Biomarkers in Body Fluids

    • Authors: Tibor Pasinszki, Melinda Krebsz
      First page: 55
      Abstract: Celiac disease is a chronic gluten-initiated autoimmune disorder that predominantly damages the mucosa of the small intestine in genetically-susceptible individuals. It affects a large and increasing number of the world’s population. The diagnosis of this disease and monitoring the response of patients to the therapy, which is currently a life-long gluten-free diet, require the application of reliable, rapid, sensitive, selective, simple, and cost-effective analytical tools. Celiac disease biomarker detection in full blood, serum, or plasma offers a non-invasive way to do this and is well-suited to being the first step of diagnosis. Biosensors provide a novel and alternative way to perform conventional techniques in biomarker sensing, in which electrode material and architecture play important roles in achieving sensitive, selective, and stable detection. There are many opportunities to build and modify biosensor platforms using various materials and detection methods, and the aim of the present review is to summarize developments in this field.
      Citation: Biosensors
      PubDate: 2018-06-16
      DOI: 10.3390/bios8020055
      Issue No: Vol. 8, No. 2 (2018)
       
  • Biosensors, Vol. 8, Pages 56: Design and Parameter Study of Integrated
           

    • Authors: Amir Shamloo, Saba Ahmad, Maede Momeni
      First page: 56
      Abstract: Being the second cause of mortality across the globe, there is now a persistent effort to establish new cancer medication and therapies. Any accomplishment in treating cancers entails the existence of accurate identification systems empowering the early diagnosis. Recent studies indicate CTCs’ potential in cancer prognosis as well as therapy monitoring. The chief shortcoming with CTCs is that they are exceedingly rare cells in their clinically relevant concentration. Here, we simulated a microfluidic construct devised for immunomagnetic separation of the particles of interest from the background cells. This separation unit is integrated with a mixer subunit. The mixer is envisioned for mixing the CTC enriched stream with lysis buffer to extract the biological material of the cell. Some modification was proposed on mixing geometry improving the efficacy of the functional unit. A valuation of engaged forces was made and some forces were neglected due to their order of magnitude. The position of the magnet was also optimized by doing parametric study. For the mixer unit, the effect of applied voltage and frequency on mixing index was studied to find the optimal voltage and frequency which provides better mixing. Above-mentioned studies were done on isolated units and the effect of each functional unit on the other is not studied. As the final step, an integrated microfluidic platform composed of both functional subunits was simulated simultaneously. To ensure the independence of results from the grid, grid studies were also performed. The studies carried out on the construct reveal its potential for diagnostic application.
      Citation: Biosensors
      PubDate: 2018-06-18
      DOI: 10.3390/bios8020056
      Issue No: Vol. 8, No. 2 (2018)
       
 
 
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