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BIOLOGY (1586 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 29)
Achievements in the Life Sciences     Open Access   (Followers: 7)
ACS Pharmacology & Translational Science     Hybrid Journal   (Followers: 2)
ACS Synthetic Biology     Hybrid Journal   (Followers: 28)
Acta Biologica Colombiana     Open Access   (Followers: 7)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 5)
Acta Biologica Sibirica     Open Access   (Followers: 2)
Acta Biologica Turcica     Open Access  
Acta Biologica Venezuelica     Open Access  
Acta Biomaterialia     Hybrid Journal   (Followers: 30)
Acta Biotheoretica     Hybrid Journal   (Followers: 3)
Acta Chiropterologica     Full-text available via subscription   (Followers: 7)
acta ethologica     Hybrid Journal   (Followers: 4)
Acta Fytotechnica et Zootechnica     Open Access   (Followers: 1)
Acta Limnologica Brasiliensia     Open Access   (Followers: 4)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Musei Silesiae, Scientiae Naturales     Open Access   (Followers: 1)
Acta Neurobiologiae Experimentalis     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 12)
Acta Scientiarum. Biological Sciences     Open Access   (Followers: 2)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis     Open Access   (Followers: 1)
Actualidades Biológicas     Open Access   (Followers: 1)
Advanced Biosystems     Hybrid Journal  
Advanced Health Care Technologies     Open Access   (Followers: 8)
Advanced Journal of Graduate Research     Open Access  
Advanced Nonlinear Studies     Hybrid Journal  
Advanced Quantum Technologies     Hybrid Journal  
Advanced Studies in Biology     Open Access  
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Bioinformatics     Open Access   (Followers: 20)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4)
Advances in Biology     Open Access   (Followers: 12)
Advances in Cell Biology/ Medical Journal of Cell Biology     Open Access   (Followers: 30)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 14)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 13)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 7)
Advances in Ecological Research     Full-text available via subscription   (Followers: 44)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 17)
Advances in Enzyme Research     Open Access   (Followers: 11)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 8)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in High Energy Physics     Open Access   (Followers: 22)
Advances in Human Biology     Open Access   (Followers: 4)
Advances in Life Science and Technology     Open Access   (Followers: 19)
Advances in Life Sciences     Open Access   (Followers: 6)
Advances in Marine Biology     Full-text available via subscription   (Followers: 21)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 25)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 6)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Tropical Biodiversity and Environmental Sciences     Open Access   (Followers: 1)
Advances in Virus Research     Full-text available via subscription   (Followers: 6)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 8)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 2)
Ageing Research Reviews     Hybrid Journal   (Followers: 12)
Aging Cell     Open Access   (Followers: 25)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
AJP Cell Physiology     Hybrid Journal   (Followers: 18)
AJP Endocrinology and Metabolism     Hybrid Journal   (Followers: 24)
AJP Lung Cellular and Molecular Physiology     Hybrid Journal   (Followers: 3)
Al-Kauniyah : Jurnal Biologi     Open Access  
Alasbimn Journal     Open Access   (Followers: 2)
Alces : A Journal Devoted to the Biology and Management of Moose     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 9)
American Journal of Bioethics     Hybrid Journal   (Followers: 14)
American Journal of Human Biology     Hybrid Journal   (Followers: 17)
American Journal of Medical and Biological Research     Open Access   (Followers: 10)
American Journal of Plant Sciences     Open Access   (Followers: 20)
American Journal of Primatology     Hybrid Journal   (Followers: 17)
American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 80)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anadol University Journal of Science and Technology B : Theoritical Sciences     Open Access  
Anadolu University Journal of Science and Technology : C Life Sciences and Biotechnology     Open Access   (Followers: 2)
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 12)
Anatomical Science International     Hybrid Journal   (Followers: 3)
Animal Cells and Systems     Hybrid Journal   (Followers: 5)
Animal Models and Experimental Medicine     Open Access  
Annales de Limnologie - International Journal of Limnology     Hybrid Journal   (Followers: 1)
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia     Open Access   (Followers: 1)
Annals of Applied Biology     Hybrid Journal   (Followers: 7)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 19)
Annals of Human Biology     Hybrid Journal   (Followers: 5)
Annals of Science and Technology     Open Access  
Annual Research & Review in Biology     Open Access  
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 14)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 25)
Annual Review of Cancer Biology     Full-text available via subscription   (Followers: 3)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 39)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 26)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 13)
Anthropological Review     Open Access   (Followers: 24)
Antibiotics     Open Access   (Followers: 9)
Antioxidants     Open Access   (Followers: 5)
Antioxidants & Redox Signaling     Hybrid Journal   (Followers: 9)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apidologie     Hybrid Journal   (Followers: 4)
Apmis     Hybrid Journal   (Followers: 1)
APOPTOSIS     Hybrid Journal   (Followers: 9)
Applied Biology     Open Access   (Followers: 1)
Applied Bionics and Biomechanics     Open Access   (Followers: 7)
Applied Vegetation Science     Full-text available via subscription   (Followers: 10)
Aquaculture Environment Interactions     Open Access   (Followers: 4)
Aquaculture International     Hybrid Journal   (Followers: 26)
Aquaculture Reports     Open Access   (Followers: 3)
Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society     Open Access   (Followers: 7)
Aquatic Biology     Open Access   (Followers: 6)
Aquatic Ecology     Hybrid Journal   (Followers: 37)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 15)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 23)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biological Sciences     Open Access  
Archives of Microbiology     Hybrid Journal   (Followers: 10)
Archives of Natural History     Hybrid Journal   (Followers: 8)
Archives of Oral Biology     Hybrid Journal   (Followers: 3)
Archives of Virology     Hybrid Journal   (Followers: 5)
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arquivos do Museu Dinâmico Interdisciplinar     Open Access  
Arthropod Structure & Development     Hybrid Journal   (Followers: 2)
Arthropods     Open Access   (Followers: 1)
Artificial DNA: PNA & XNA     Hybrid Journal   (Followers: 3)
Asian Bioethics Review     Full-text available via subscription   (Followers: 3)
Asian Journal of Biodiversity     Open Access   (Followers: 5)
Asian Journal of Biological Sciences     Open Access   (Followers: 3)
Asian Journal of Biology     Open Access  
Asian Journal of Biotechnology and Bioresource Technology     Open Access  
Asian Journal of Cell Biology     Open Access   (Followers: 5)
Asian Journal of Developmental Biology     Open Access   (Followers: 2)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 4)
Asian Journal of Nematology     Open Access   (Followers: 4)
Asian Journal of Poultry Science     Open Access   (Followers: 4)
Atti della Accademia Peloritana dei Pericolanti - Classe di Scienze Medico-Biologiche     Open Access  
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 4)
Avian Biology Research     Full-text available via subscription   (Followers: 5)
Avian Conservation and Ecology     Open Access   (Followers: 14)
Bacteriology Journal     Open Access   (Followers: 1)
Bacteriophage     Full-text available via subscription   (Followers: 3)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Plant Taxonomy     Open Access  
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Batman Üniversitesi Yaşam Bilimleri Dergisi     Open Access  
Berita Biologi     Open Access   (Followers: 1)
Between the Species     Open Access   (Followers: 1)
Bio Tribune Magazine     Hybrid Journal  
BIO Web of Conferences     Open Access  
BIO-Complexity     Open Access  
Bio-Grafía. Escritos sobre la Biología y su enseñanza     Open Access  
Bio-Lectura     Open Access  
Bioanalytical Reviews     Hybrid Journal   (Followers: 2)
Biocatalysis and Biotransformation     Hybrid Journal   (Followers: 6)
BioCentury Innovations     Full-text available via subscription   (Followers: 1)
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 16)
Biochimie     Hybrid Journal   (Followers: 6)
BioControl     Hybrid Journal   (Followers: 6)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 8)
Biodemography and Social Biology     Hybrid Journal  
BioDiscovery     Open Access   (Followers: 2)
Biodiversidade e Conservação Marinha : Revista CEPSUL     Open Access  
Biodiversitas : Journal of Biological Diversity     Open Access  
Biodiversity Data Journal     Open Access   (Followers: 4)
Biodiversity Informatics     Open Access   (Followers: 1)
Biodiversity Information Science and Standards     Open Access   (Followers: 2)
Biodiversity: Research and Conservation     Open Access   (Followers: 26)
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Bioelectromagnetics     Hybrid Journal   (Followers: 2)
Bioenergy Research     Hybrid Journal   (Followers: 3)
Bioengineering and Bioscience     Open Access   (Followers: 3)
BioEssays     Hybrid Journal   (Followers: 11)
Bioethics     Hybrid Journal   (Followers: 17)
BioéthiqueOnline     Open Access  
Biofabrication     Hybrid Journal   (Followers: 5)
Biofilms     Full-text available via subscription   (Followers: 2)
Biogeosciences (BG)     Open Access   (Followers: 11)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 3)
Bioinformatics     Hybrid Journal   (Followers: 391)
Bioinformatics and Biology Insights     Open Access   (Followers: 12)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 7)
Biointerphases     Open Access   (Followers: 1)
Biojournal of Science and Technology     Open Access  
BioLink : Jurnal Biologi Lingkungan, Industri, Kesehatan     Open Access   (Followers: 1)
Biologia     Hybrid Journal  

        1 2 3 4 5 6 7 8 | Last

Similar Journals
Journal Cover
Journal Prestige (SJR): 0.85
Citation Impact (citeScore): 4
Number of Followers: 2  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1567-5394
Published by Elsevier Homepage  [3168 journals]
  • Highly uniform in-situ cell electrotransfection of adherent cultures using
           grouped interdigitated electrodes
    • Abstract: Publication date: Available online 30 November 2019Source: BioelectrochemistryAuthor(s): Yicen Zhou, Ying Lu, Jing Cheng, Youchun XuAbstractCell electrotransfection is an effective approach for transferring exogenous molecules into living cells by electric stimulation. The existing in-situ electrotransfection micro-devices for adherent cells exhibit the drawbacks of low transfection efficiency and low cell viability. An important reason for these drawbacks is the unequal exposure of cells to the electric field. It was found that cells growing directly below the energized electrodes experience a much lower electric field intensity when compared to the cells growing below the spacing area of the electrodes, resulting in low transfection with a strip-like pattern. Therefore, a new strategy for the in-situ electrotransfection of adherent cells growing in a standard 12-well plate is proposed in this study. By sequentially energizing electrodes arranged in a nested and non-contact manner, the cells were exposed to an overall equal intensity of the electric field, and thus a higher efficiency of transfection was achieved. The seven cell lines transfected using this method exhibited high transfection efficiency and high cell viability, demonstrating the potential for studying gene function.
  • Electrochemical characterization and estimation of DNA-binding capacity of
           a series of novel ferrocene derivatives
    • Abstract: Publication date: Available online 30 November 2019Source: BioelectrochemistryAuthor(s): Marko Pešić, Jovana Bugarinović, Aleksandra Minić, Slađana Novaković, Goran Bogdanović, Anka Todosijević, Dragana Stevanović, Ivan DamljanovićThe synthesis of a series of methyl 2-alkyl-5-aryl-4-ferrocenoylpyrrolidine-2-carboxylates has been achieved by [3+2] dipolar cycloaddition of azomethine ylides to acryloylferrocene. The electrochemical properties of novel products were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These techniques revealed the quasi-reversible one-electron oxidation process. The DNA-binding capacity of all the products was also studied using CV and DPV, and significant interactions between synthesized compounds and nucleic acid, mostly of the electrostatic type, were disclosed. DFT calculations and molecular docking tests were carried out to gain a more exhaustive insight into the interactions of the obtained products with nucleic acid. A detailed characterization of the new compounds was performed by IR, NMR and elemental analyses, followed by single-crystal X-ray diffraction experiments for two representatives.Graphical abstractGraphical abstract for this article
  • Microwave-assisted preparation of ZnFe2O4-Ag/rGO nanocomposites for
           amplification signal detection of alpha-fetoprotein
    • Abstract: Publication date: Available online 30 November 2019Source: BioelectrochemistryAuthor(s): Mei Wu, Yuxiao Yang, Kaihang Cao, Chulei Zhao, Xiuwen Qiao, Chenglin HongIn this study, a novel signal-amplified immunosensor was designed by using a microwave-assisted self-assembly method to synthesize ZnFe2O4-Ag/rGO nanocomposites. The conductivity of ZnFe2O4-rGO nanocomposites was significantly improved due to the effective inhibition of rGO accumulation by the insertion of ZnFe2O4 and Ag nanoparticles (NPs) into graphene sheets. Excellent sensitivity and reproducibility were achieved through the microwave-assisted preparation of ZnFe2O4-Ag/rGO nanocomposites as a substrate, with the Ag NPs enhancing the signal because of the effective conductive matrix. The layer assembly process of the immunosensor was verified by cyclic voltammetry and electrochemical impedance spectroscopy. Under optimal conditions, the fabricated immunosensor showed good linearity over a wide concentration range from 1 pg mL-1 to 200 ng mL-1 with a low detection limit of 0.98 pg mL-1, and exhibited excellent specificity, good stability, and reproducibility. These qualities can contribute to the successful application of a label-free immunosensor in the detection of AFP in human serum.Graphical abstractGraphical abstract for this article
  • Employment of electrostriction phenomenon for label-free electrochemical
           immunosensing of tetracycline
    • Abstract: Publication date: Available online 29 November 2019Source: BioelectrochemistryAuthor(s): Karolina Starzec, Cecilia Cristea, Mihaela Tertis, Bogdan Feier, Marcin Wieczorek, Paweł Kościelniak, Jolanta KochanaThe presented work describes a simple label-free electrochemical immunosensor for the determination of tetracycline (TC). The functioning of the sensor was based on the electrostriction of a antibody-terminated thiol layer self-assembled on a gold electrode surface, serving as a dielectric membrane. The intensity of electrostriction was correlated with the amount of TC captured through an affinity reaction with its specific antibody, and was followed in the form of capacitance-potential curves. The process of the immunosensor construction was optimized using electrochemical impedance spectroscopy (EIS). The chemisorption time of the thiol, the duration of the TCAb immobilization and its concentration were optimized. The developed immunosensor exhibited a linear response in two concentration ranges: from 0.95 to 10 μmol L–1 and from 10 to 140 μmol L–1, with the mean sensitivity of 6.27 nF μmol-1 L (88.67 nF μmol–1 L cm-2) and 0.56 nF μmol-1 L (7.84 nF μmol–1 L cm–2), respectively. The limit of detection was evaluated as 28 nmol L−1. The specificity of the proposed sensor toward other antibiotics, amoxicillin and ciprofloxacin, was examined. The immunosensor was successfully employed to quantify TC in a tablet form and in a matrix of river water.Graphical abstractGraphical abstract for this article
  • Development of a molecularly imprinted polymer electrochemical sensor and
           its application for sensitive detection and determination of malathion in
           olive fruits and oils
    • Abstract: Publication date: Available online 29 November 2019Source: BioelectrochemistryAuthor(s): Youssra Aghoutane, Alassane Diouf, Lars Österlund, Benachir Bouchikhi, Nezha El BariAbstractMalathion (MAL) is an organophosphorus (OP) insecticide. It is a cholinesterase inhibitor, which can pose serious health and environmental problems. In this study, a sensitive and selective molecular imprinted polymer (MIP) based on screen-printed gold electrodes (Au-SPE) for MAL detection in olive oils and fruits, was devised. The MIP sensor was prepared using acrylamide as the functional monomer and MAL as the template. Subsequently, the morphology of the electrode surface was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical characterization of the developed MIP sensor was performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) techniques. The operational repeatability and stability of the sensor were studied. It was found to have a dynamic concentration range of (0.1 pg mL-1-1000 pg mL-1) and a low limit of detection (LOD) of 0.06 pg mL-1. Furthermore, the sensor was employed to determine MAL content in olive oil with a recovery rate of 87.9% and a relative standard deviation of 8%. It was successfully applied for MAL determination in real samples and promise to open new opportunities for the detection of OP pesticides residues in various food products, as well as in environmental applications.
  • Bioelectrical model of head-tail patterning based on cell ion channels and
           intercellular gap junctions
    • Abstract: Publication date: Available online 29 November 2019Source: BioelectrochemistryAuthor(s): Javier Cervera, Salvador Meseguer, Michel Levin, Salvador MafeRobust control of anterior-posterior axial patterning during regeneration is mediated by bioelectric signaling. However, a number of systems-level properties of bioelectrochemical circuits, including stochastic outcomes such as seen in permanently de-stabilized “cryptic” flatworms, are not completely understood. We present a bioelectrical model for head-tail patterning that combines single-cell characteristics such as membrane ion channels with multicellular community effects via voltage-gated gap junctions. It complements the biochemically-focused models by describing the effects of intercellular electrochemical coupling, cutting plane, and gap junction blocking of the multicellular ensemble. We provide qualitative insights into recent experiments concerning planarian anterior/posterior polarity by showing that: (i) bioelectrical signals can help separated cell domains to know their relative position after injury and contribute to the transitions between the abnormal double-head state and the normal head–tail state; (ii) the bioelectrical phase-space of the system shows a bi-stability region that can be interpreted as the cryptic system state; and (iii) context-dependent responses are obtained depending on the cutting plane position, the initial bioelectrical state of the multicellular system, and the intercellular connectivity. The model reveals how simple bioelectric circuits can exhibit complex tissue-level patterning and suggests strategies for regenerative control in vivo and in synthetic biology contexts.Graphical abstractBioelectrical phase space of head-tail axial patterning for planaria.Graphical abstract for this article
  • Pyranose Oxidase: A Versatile Sugar Oxidoreductase for Bioelectrochemical
    • Abstract: Publication date: Available online 29 November 2019Source: BioelectrochemistryAuthor(s): Annabelle T. Abrera, Leander Sützl, Dietmar HaltrichAbstractPyranose oxidase (POx) is an FAD-dependent oxidoreductase, and like glucose oxidase (GOx) it is a member of the glucose-methanol-choline (GMC) superfamily of oxidoreductases. POx oxidizes several monosaccharides including D-glucose, D-galactose, and D-xylose, while concurrently oxygen is reduced to hydrogen peroxide. In addition to this oxidase activity, POx shows pronounced activity with alternative electron acceptors that include various quinones or (complexed) metal ions. Even though POx in general shows properties that are more favourable than those of GOx (e.g., a considerably higher catalytic efficiency (kcat/Km) for D-glucose, significantly lower Michaelis constants Km for D-glucose, reactivity with both anomeric forms of D-glucose) it is much less frequently used for both biosensor and biofuel cell applications than GOx. POx has been applied in biosensing of D-glucose, D-galactose, and D-xylose, and in combination with α-glucosidase also maltose. An attractive application is in biosensors constructed for the measurement of 1,5-anhydro-D-glucitol, a recognised biomarker in diabetes. Bioelectrochemical applications of POx had been restricted to enzymes of fungal origin. The recent discovery and characterisation of POx from bacterial sources, which show properties that are very distinct from the fungal enzymes, might open new possibilities for further applications in bioelectrochemistry.
  • The protection mechanism offered by Heterophragma adenophyllum extract
           against Fe-C steel dissolution at low pH: Computational, statistical and
           electrochemical investigations
    • Abstract: Publication date: Available online 27 November 2019Source: BioelectrochemistryAuthor(s): Priti Pahuja, Nisha Saini, Bhaskaran, Abdelkarim Chaouiki, Rachid Salghi, Sumit Kumar, Suman LataAbstractAn ethanolic extract of Heterophragma adenophyllum (HA) was investigated as corrosion inhibitor for Fe-C steel in hydrochloric acid. The inhibition effect of HA extract was examined using the weight deterioration, electrochemical impedance spectroscopy (EIS) and polarization techniques. EIS showed enhanced charge transfer resistance with maximum protection value of ∼96% at 600 ppm concentration. Tafel extrapolation results revealed that corrosion was restricted by mixed inhibition. The icorr values reduced considerably from 53.63 μA cm-2 at 100 ppm to 20.11 μA cm-2 at 600 ppm of HA extract. Interaction intensity was further examined through Langmuir, Freundlich, D-R, Frumkin, and Flory-Huggins adsorption isotherms. The computational study, statistical modelling and surface morphology by XPS, AFM, and SEM-EDX, indicated an excellent adsorption capability of HA on Fe-C steel.
  • Electron donor availability controls scale up of anodic biofilms
    • Abstract: Publication date: Available online 27 November 2019Source: BioelectrochemistryAuthor(s): Secil Tutar, Abdelrhman Mohamed, Phuc T. Ha, Haluk BeyenalAbstractThe scale-up of bioelectrochemical systems (BESs) is a challenging problem that limits the advancement and practical implementation of the coupled technology. The goal of this work is to acquire an understanding of the limitations on scaling up anodic biofilms in BESs. We hypothesized that scaling up is dependent on the availability of electron donors. We tested this hypothesis by enriching anodic biofilms on electrodes of multiple sizes (15 cm2 to 466 cm2) and quantified the anodic current densities while varying the electron donor concentrations. The anodic biofilms were enriched on electrodes under two conditions: 1) in raw wastewater and 2) in wastewater supplemented with 20 mM acetate. Following anodic biofilm enrichment, the current density for each electrode was quantified in artificial wastewater medium with variable COD loadings using acetate as an electron donor. Current generated using anodic biofilms scaled up at a high COD loading (1500 mg/L), while current density decreased with increasing electrode size at lower COD loadings. Further, microbial community analysis revealed that the microbial community was independent of the electrode size but dependent on the medium composition during the enrichment phase. These results provide a practical framework for the design of large-scale BESs based on laboratory-scale measurements.
  • The effect of start-up on energy recovery and compositional changes in
           brewery wastewater in bioelectrochemical systems
    • Abstract: Publication date: Available online 26 November 2019Source: BioelectrochemistryAuthor(s): Johanna M. Haavisto, Marika E. Kokko, Aino-Maija Lakaniemi, Mira L.K. Sulonen, Jaakko A. PuhakkaStart-up of bioelectrochemical systems (BESs) fed with brewery wastewater was compared at different adjusted anode potentials (-200 and 0 mV vs. Ag/AgCl) and external resistances (50 and 1000 Ω). Current generation stabilized faster with the external resistances (9±3 and 1.70±0.04 A/m3 with 50 and 1000 Ω, respectively), whilst significantly higher current densities of 76±39 and 44±9 A/m3 were obtained with the adjusted anode potentials of -200 and 0 mV vs. Ag/AgCl, respectively. After start-up, when operated using 47 Ω external resistance, the current densities and Coulombic efficiencies of all BESs stabilized to 9.5±2.9 A/m3 and 12±2%, respectively, demonstrating that the start-up protocols were not critical for long-term BES operation in MFC mode. With adjusted anode potentials, two times more biofilm biomass (measured as protein) was formed by the end of the experiment as compared to start-up with the fixed external resistances. After start-up, the organics in the brewery wastewater, mainly sugars and alcohols, were transformed to acetate (1360±250 mg/L) and propionate (610±190 mg/L). Optimized start-up is required for prompt BES recovery, for example, after process disturbances. Based on the results of this study, adjustment of anode potential to -200 mV vs. Ag/AgCl is recommended for fast BES start-up.Graphical abstractGraphical abstract for this article
  • Microbiologically influenced corrosion mechanism of 304L stainless steel
           in treated urban wastewater and protective effect of silane-TiO2 coating
    • Abstract: Publication date: Available online 21 November 2019Source: BioelectrochemistryAuthor(s): I. Ziadi, M.M. Alves, M. Taryba, L. El-Bassi, H. Hassairi, L. Bousselmi, M.F. Montemor, H. AkroutMicrobiologically influenced corrosion (MIC) of bare and silane-TiO2 sol-gel coated stainless steel (SS) was studied in treated urban wastewater (TUWW). Combining the electrochemical impedance spectroscopy (EIS) and the scanning vibrating electrode technique (SVET) showed that SS surface colonization occurs, at earlier stages, by iron-oxidizing bacteria (IOB), and later by sulphate-reducing bacteria (SRB). The SVET results showed that chemical corrosion process and bacterial respiration led to the depletion of dissolved oxygen, creating a differential aeration cell and thus a localized corrosion phenomenon. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that the growth of a bacterial biofilm on 304L SS was a dynamic process, stimulating the localized oxidation of SS. To improve corrosion protection, a silane-TiO2 sol-gel coating for SS is proposed. SEM showed that the coating reduced bacterial adhesion and EIS study demonstrated that the coating improved the barrier properties and corrosion resistance of 304L SS in TUWW over a short period of immersion.Graphical abstractGraphical abstract for this article
  • FAD dependent glucose dehydrogenases – discovery and engineering of
           representative glucose sensing enzymes -
    • Abstract: Publication date: Available online 20 November 2019Source: BioelectrochemistryAuthor(s): Junko Okuda-Shimazaki, Hiromi Yoshida, Koji SodeAbstractThe history of the development of glucose sensors goes hand-in-hand with the history of discovery and engineering of glucose-sensing enzymes. Glucose oxidase (GOx) has been used for glucose sensing since the development of the first electrochemical glucose sensor. The principle utilizing oxygen as the electron acceptor is designated as the first-generation electrochemical enzyme sensors. With increasing demand for hand-held and cost-effective devices for the “self-monitoring of blood glucose (SMBG)”, second-generation electrochemical sensor strips employing electron mediators have become the most popular platform. To overcome the inherent drawback of GOx, namely, the use of oxygen as the electron acceptor, various glucose dehydrogenases (GDHs) have been utilized in second-generation principle-based sensors. Among the various enzymes employed in glucose sensors, GDHs harboring FAD as the redox cofactor, FADGDHs, especially those derived from fungi, fFADGDHs, are currently the most popular enzymes in the sensor strips of second-generation SMBG sensors. In addition, the third-generation principle, employing direct electron transfer (DET), is considered the most elegant approach and is ideal for use in electrochemical enzyme sensors. However, glucose oxidoreductases capable of DET are limited. One of the most prominent GDHs capable of DET is a bacteria-derived FADGDH complex (bFADGDH). bFADGDH has three distinct subunits; the FAD harboring the catalytic subunit, the small subunit, and the electron-transfer subunit, which makes bFADGDH capable of DET. In this review, we focused on the two representative glucose sensing enzymes, fFADGDHs and bFADGDHs, by presenting their discovery, sources, and protein and enzyme properties, and the current engineering strategies to improve their potential in sensor applications. (254 words)
  • Surface Modification of Cerasomes with AuNPs@Poly(Ionic Liquid)s for an
           Enhanced Stereo Biomimetic Membrane Electrochemical Platform
    • Abstract: Publication date: Available online 20 November 2019Source: BioelectrochemistryAuthor(s): Daliang Liu, Qiong Wu, Shun Zou, Feiyun Bao, Jun-ichi Kikuchi, Xi-Ming SongA novel liposomal nanocomposite, Au@PIL-cerasome, with biocompatibility and conductivity was fabricated via the self-assembly of cerasomes and gold nanoparticles (AuNPs) stabilized by poly(ionic liquid)s (PILs). The surface charge, morphology and chemical composition of the nanocomposites were characterized by the zeta potential, UV-vis, TEM, SEM and EDS. The nanocomposites exhibited structural stability directly on the surface of solid electrodes, without fusion. Electrochemical impedance experiments demonstrated that the nanocomposites had an enhanced conductivity compared with unmodified cerasomes. Horseradish peroxidase (HRP), as a reporter, was immobilized on the nanocomposites without denaturation or inactivation. The direct electron transfer of HRP was achieved, and the HRP/Au@PIL-cerasome/GCE exhibited an amplified current and improved electrocatalytic activity. Activity towards H2O2 displayed a linear range over 10-70 μM and a detection limit of 3.3 μM. Activity towards NO2- displayed linear ranges over 1-5 mM and 5-1280 mM, and the limit of detection was 0.11 mM. In addition, the electrode was stable and reproducible, with 6% RSD. Such multi-component liposomal nanocomposites with an enhanced electrical performance pave a better way for building novel and straightforward 3D stereo biomimetic electrochemical platforms and even molecular communication systems to investigate information transduction between cells.Graphical abstractGraphical abstract for this article
  • Reduced nonspecific protein adsorption by application of
           diethyldithiocarbamate in receptor layer of diphtheria toxoid
           electrochemical immunosensor
    • Abstract: Publication date: Available online 20 November 2019Source: BioelectrochemistryAuthor(s): Robert Ziółkowski, Adrianna Kaczmarek, Ilona Kośnik, Elżbieta MalinowskaAbstractThe immunoassay technology is of particular importance for both the environmental industry and clinical analysis. Biosensors, with the sensing layer based on antibodies or their fragments, offer high selectivity and short detection times. However, analytical devices where the electrochemical signal corresponds to changes in the interfacial region (sensing layer/electrode surface) are very susceptible to any nonspecific adsorption. Unfortunately, proteins (including antibodies) belong to the molecules showing high non-specific interactions with solid substrates. Herein, we propose diethyldithiocarbamate as a new antifouling and highly conductive agent. The investigations were conducted to evaluate its interaction with chosen proteins and the mechanism of its co-adsorption with biotinylated thiol (an anchor point for immune-sensing elements). The developed receptor layer is characterised by reduced nonspecific protein adsorption and high conductivity with the same preserved specificity of the antibodies (immobilised by the streptavidin/biotin bioaffinity technique). This allowed for selective detection of the diphtheria toxoid, an inactive toxin secreted by virulent strains of Corynebacterium diphtheria, at the level of 5⋅10-6 μg⋅ml-1 (1⋅10-6 Lf⋅ml-1) and in the real-life sample.
  • Pyranose dehydrogenases: Rare Enzymes for electrochemistry and
    • Abstract: Publication date: Available online 20 November 2019Source: BioelectrochemistryAuthor(s): Clemens K. PeterbauerPyranose dehydrogenase is a flavin-dependent carbohydrate oxidoreductase classified among Auxiliary Activities Family 3, along with structurally and catalytically related enzymes like pyranose oxidase and cellobiose dehydrogenase, and probably fulfils biological functions in lignocellulose breakdown. It is limited to a rather small group of litter-decomposing basidiomycetes adapted to humic-rich habitats, and shows an equally rare combination of structural and biochemical properties. It displays broader substrate specificity and regioselectivity compared to similar enzymes, catalyzing monooxidations at C1, C2, C3 or dioxidations at C2,3 or C3,4, depending on the pyranose sugar form (mono-/di-/oligo-saccharide or glycoside) and the enzyme source. It is unable to utilize oxygen as electron acceptor, using substituted benzoquinones and (organo)metallic ions instead, which suggests a role in redox cycling of (hydro)quinones and complexed metal ions. Pyranose dehydrogenase is a promising candidate for enzymatic sensors of various sugars, for the anodic reaction in enzymatic biofuel cells powered by carbohydrate mixtures, and as a versatile biocatalyst for the production of di- and tri-carbonyl sugar derivatives as chiral intermediates for the synthesis of rare sugars, novel drugs and fine chemicals.Graphical abstractGraphical abstract for this article
  • Corrosion behavior and mechanism of carbon steel influenced by interior
           deposit microflora of an in-service pipeline
    • Abstract: Publication date: Available online 19 November 2019Source: BioelectrochemistryAuthor(s): Hong Su, Ruohao Tang, Xiaowei Peng, Aiguo Gao, Yejun HanAbstractInvestigation of carbon steel corrosion influenced by in-situ microbial communities can provide reliable information about microbiologically influenced corrosion (MIC) in the oil and gas field. Here, we investigated the 90-day corrosion behavior of Q235 carbon steel influenced by interior deposit microflora of an in-service pipeline using open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Linear sweep voltammetry (LSV), 16S rRNA gene sequencing, and surface analysis were used to comprehensively analyze the corrosion mechanisms. The results indicated that OCP was decreased while the charge transfer resistance (Rct) was increased, and that steel corrosion was inhibited during the first 45 days. Subsequently, OCP was significantly increased while Rct was rapidly decreased, and steel corrosion was enhanced. After 90-day immersion, severe pitting corrosion with a maximum pit depth of 89.6 μm occurred on the steel surface. Viable microbes in the final biofilm significantly increased the cathodic current. Iron carbonate, chukanovite and cementite were identified as the main corrosion products on the steel surface. Methanobacterium dominated the final biofilm community. These observations indicate that the corrosion mechanism of the final biofilm can be explained by extracellular electron transfer MIC in which microbes corrode steel by direct electron uptake.
  • The Effect of Anode Hydrodynamics on the Sensitivity of Microbial Fuel
           Cell Based Biosensors and the Biological Mechanism
    • Abstract: Publication date: Available online 18 November 2019Source: BioelectrochemistryAuthor(s): Yue Yi, Beizhen Xie, Ting Zhao, Ziniu Qian, Hong LiuFluid dynamics in the anodic chamber of a microbial fuel cell (MFC) is a key factor affecting the distribution of substrates and the efficiency of mass transport. However, the effect of hydrodynamics on MFC based biosensor (MFC-Biosensor) sensitivity has not been established. In this study, the three-dimension anode flow field of a two chamber MFC was visualized, and anodic configuration optimized by a reasonable serpentine flow field and inlet/outlet settings. Through optimization, the proportion of the dead zone in the anodic configuration decreased by 14.1%, and the velocity at the anode surface increased by 334.6% with better homogeneity of distribution. Moreover, electricity production and sensitivity for the detection biotoxicity at MFC-Biosensors improved by 23.1% and 46.1-52.3%, respectively. Biofilm viability analysis further proved that the enhanced surface velocity was of benefit for the permeation of toxicants into anodic biofilms, thus improving the sensor performance.Graphical abstractGraphical abstract for this article
  • Molecularly imprinted electrochemical sensor based on
           polypyrrole/dopamine@graphene incorporated with surface molecularly
           imprinted polymers thin film for recognition of olaquindox
    • Abstract: Publication date: Available online 15 November 2019Source: BioelectrochemistryAuthor(s): Xiaoyun Bai, Bo Zhang, Miao Liu, Xuelian Hu, Guozhen Fang, Shuo WangAbstractIn this paper, an advanced molecularly imprinted electrochemical sensor (MIECS) based on electropolymerized olaquindox (OLA) surface molecularly imprinted polymer thin film on a modified glassy carbon electrode (GCE) was developed for the detection of OLA. It was fabricated by coating dopamine@graphene (DGr) on GCE, then electropolymerizing pyrrole (Py) and molecularly imprinted polymers (MIPs). Graphene (Gr) was introduced for improving conductivity and sensitivity. Dopamine (DA) was used for dispersion and adhesion of Gr. Polypyrrole (PPy) could fix DGr and enhance the current response evidently. The established sensor could selectively recognize OLA but not the analogs of OLA. Some essential parameters controlling the performance of the developed sensor were investigated and optimized. Under optimal conditions, the linear relationship between the current intensity and OLA concentration was obtained from 50 nmol L-1 to 500 nmol L-1 with a limit of detection (LOD) of 7.5 nmol L-1. Analytical results of OLA based on the developed MIECS for fish and feedstuffs showed a good agreement with the results based on high performance liquid chromatography (HPLC).
  • Study of pitting corrosion inhibition effect on aluminum alloy in seawater
           by biomineralized film
    • Abstract: Publication date: Available online 15 November 2019Source: BioelectrochemistryAuthor(s): Yuanyuan Shen, Yaohua Dong, Tao Liu, Zhangwei Guo, Qinghong Li, Lihua Dong, Yansheng Yin, Xiaoxue WangMetallic materials can be easily corroded in marine environments, in which pitting corrosion is very common. In this study, we investigated the effect of Pseudoalteromonas lipolytica, isolated from the South China Sea on the corrosion behavior of 2A14 aluminum alloy in seawater. Surface analysis of the alloy in the presence of the bacteria was used to observe corrosion morphology and the corrosion products studied. Electrochemical method was used to analyze the corrosion susceptibility of the alloy in seawater in the presence of the bacteria. Surface analysis suggested that a protective film with CaMg(CO3)2 was gradually formed on the surface of the alloy in the presence of the bacteria. The electrochemical results showed that the radius of the impedance arc of the alloy immersed in seawater with bacteria increased gradually with time. The bacteria promoted the formation of the CaMg(CO3)2 film, which blocked seawater from the alloy and consequently, inhibited pitting corrosion.Graphical abstractGraphical abstract for this article
  • A journey in the complex interactions between electrochemistry and
           bacteriology: from electroactivity to electromodulation of bacterial
    • Abstract: Publication date: Available online 14 October 2019Source: BioelectrochemistryAuthor(s): Dominika Czerwińska-Główka, Katarzyna KrukiewiczAlthough the term bioelectrochemistry tends to be associated with animal and human tissues, bioelectric currents exist also in plants and bacteria. Especially the latter, when agglomerated in the form of biofilms, can exhibit electroactivity and susceptibility to electrical stimulation. Therefore, electrochemical methods appear to become powerful techniques to expand the conventional strategies of biofilm characterization and modification. In this review, we aim to provide the insight into the electrochemical behaviour of bacteria and present the variety of electrochemical techniques that can be used either for the non-destructive monitoring of bacterial communities or modulation of their growth. The most common applications of electrical stimulation on biofilms are presented, including the prevention of bacterial growth by charging the surface of the materials, changing the direction of bacterial movement under the influence of the electric field and increasing of the potency of antibiotics when bactericides are coupled with the electric field. Also, the industrial applications of microbial electro-technologies are described, such as bioremediation, wastewater treatment, and microbial fuel cells. Consequently, we are showing the complexity of interactions that exist between electrochemistry and bacteriology that can be used for the benefit of these two disciplines.Graphical abstractGraphical abstract for this article
  • Polyclonal Antibody Production Anti Pc_312-324 peptide. Its Potential Use
           in Electrochemical Immunosensors for Transgenic Soybean Detection
    • Abstract: Publication date: Available online 4 October 2019Source: BioelectrochemistryAuthor(s): Marcos E. Farías, Mariela M. Marani, Darío Ramírez, Ana M. Niebylski, N. Mariano Correa, Patricia G. MolinaAbstractA new polyclonal antibody that recognizes the CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS), which provides resistance to glyphosate in soybean (Roundup Ready®, RR soybean), was produced. New Zealand rabbits were injected with a synthetic peptide (Pc_312-324, (PEP)) present in the soybean CP4-EPSPS protein. The anti-PEP antibodies production was evaluated by electrophoresis (SDS-PAGE) and an enzyme-linked immunosorbent assay (ELISA) was developed in order to study their specificity. The ELISA showed that the polyclonal antibody was specific to PEP. In addition, the anti- PEP was immobilized onto a gold disk electrode and the antigen-antibody interaction was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Moreover, the EIS showed that the electron transfer resistance of the modified electrode increased after incubation with solutions containing CP4-EPSPS protein from RR transgenic soybean, while no changes were detected after incubation with no-RR soybean proteins. These results suggest that the CP4-EPSPS was immobilized onto the electrode, due to the specific interaction with the anti-PEP. These results show that this antigen-antibody interaction can be detected by electrochemical techniques, suggesting that the anti-PEP produced can be used in electrochemical immunosensors development to quantify transgenic soybean.
  • Effect of electrode spacing on electron transfer and conductivity of
           Geobacter sulfurreducens biofilms
    • Abstract: Publication date: Available online 4 October 2019Source: BioelectrochemistryAuthor(s): Panpan Liu, Abdelrhman Mohamed, Peng Liang, Haluk BeyenalTo understand electron transport in electrochemically active biofilms, it is necessary to elucidate the heterogeneous electron transport across the biofilm/electrode interface and in the interior of G. sulfurreducens biofilm by bridging gaps of varying widths. The conductivity of Geobacter sulfurreducens biofilm bridging nonconductive gaps with widths of 5 µm, 10 µm, 20 µm and 50 µm is investigated. Results of electrochemical gating measurement show that biofilm conductivity peaks at the potential of -0.35 V vs. Ag/AgCl, revealing redox-driven electron transport in the biofilm. The biofilm conductivity increases with gap width (10.4 ± 0.2 µS cm-1 in 5 µm gap, 13.3 ± 0.2 µS cm-1 in 10 µm gap, 16.7 ± 1.4 µS cm-1 in 20 µm gap and 41.8 ± 2.02 µS cm-1 in 50 µm gap). These results revealed that electron transfer in G. sulfurreducens biofilm is a redox-driven. In addition, higher biofilm conductivities and lower charge transfer resistances are observed in all gaps under a turnover condition than in those under a non-turnover condition. Our results offer insights into the spatial heterogeneity of biofilm structure and extracellular electron transfer in electrochemically active biofilms.Graphic abstractGraphical abstract for this article
  • Fabrication of an electrochemical chiral sensor via an integrated
           polysaccharides/3D nitrogen-doped graphene-CNT frame
    • Abstract: Publication date: Available online 4 October 2019Source: BioelectrochemistryAuthor(s): Xiaohui Niu, Xing Yang, Zunli Mo, Jia Wang, Zhao Pan, Zhenyu Liu, ChaoShuai, Guigui Liu, Nijuan Liu, Ruibin GuoAbstractWe report a novel chiral interface based on polysaccharides that was integrated via an amidation reaction between the -COOH of sodium alginate and the -NH2 of chitosan to form a chiral selector (SA-CS) with three dimensional N-doped graphene-CNT (NGC) as the substrate material. This interface was used for chiral discrimination of tryptophan (Trp) enantiomers via electrochemical measurements. The FT-IR, SEM, TEM and XPS characterization showed that the chiral selector and substrate materials were prepared successfully. Compared with individual SA-CS and NGC, the integrated polysaccharides/3D NGC showed higher enantioselectivity for L-Trp than D-Trp due to the smaller steric hindrance for D-Trp during the formation of three-point interactions between the two diastereoisomeric enantiomer-selector complexes, which allowed L-Trp to more easily detach from the electrode modification layer and approach the electrode surface, facilitating its approach and confirming that SA-CS had a higher constant for L-Trp when applied to real samples.
  • Contents of Volume
    • Abstract: Publication date: December 2019Source: Bioelectrochemistry, Volume 130Author(s):
    • Abstract: Publication date: December 2019Source: Bioelectrochemistry, Volume 130Author(s):
  • TOC
    • Abstract: Publication date: December 2019Source: Bioelectrochemistry, Volume 130Author(s):
  • Discovery of a novel quinohemoprotein from a eukaryote and its application
           in electrochemical devices
    • Abstract: Publication date: Available online 15 September 2019Source: BioelectrochemistryAuthor(s): Kouta Takeda, Kiyohiko Igarashi, Makoto Yoshida, Nobuhumi NakamuraPyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase is one of the extensively studied sugar-oxidizing enzymes used as a biocatalyst for biosensors and biofuel cells. A novel pyranose dehydrogenase (CcPDH) derived from the basidiomycete Coprinopsis cinerea is the first discovered eukaryotic PQQ-dependent enzyme. This enzyme carries a b-type cytochrome domain that is homologous to the cytochrome domain of cellobiose dehydrogenase (CDH); thus, CcPDH is a quinohemoprotein. CcPDH catalyzes the oxidation of various aldose sugars and shows significant activity toward the reverse-chair conformation of pyranoses. Interdomain electron transfer occurs in CcPDH similar to CDH, from the PQQ cofactor in the catalytic domain to the heme b in the cytochrome domain. This enzyme is able to direct electrical communication with electrodes, without artificial electron mediators, thus allowing direct electron transfer (DET)-type bioelectrocatalysis. In this review, we briefly describe recent progress in research on the biochemical discovery of CcPDH and the development of (bio)electrochemical applications (an amperometric biosensor) based on DET reactions.Graphical abstractUnlabelled Image
  • Evaluation of the biocompatibility of a PVA/SA scaffold with a human
    • Abstract: Publication date: Available online 15 September 2019Source: BioelectrochemistryAuthor(s): M. Hernández, M.A. Álvarez-Pérez, J. Genesca, K.K. Gómez, A. CoveloAbstractThe biocompatibility of human gingival fibroblasts (HGF) was evaluated in different concentrations of poly(vinyl alcohol) and sodium alginate (PVA/SA) nanofibres (3.5 wt% 4 wt% and 5 wt%). The PVA/SA nanofibres were deposited on the surface of an electrode microchip by using the electrospinning technique. Electrochemical impedance spectroscopy (EIS) was applied to measure the dielectric properties of each system. In order to provide a detailed analysis as well as a right physical interpretation of the EIS results, the data was fitted with an electric equivalent circuit based on the EIS and the microscopic assessments. The results registered three different time constants (TCs) of the PVA/SA scaffold which indicated different layers at different depths of the scaffold. The TCs changed their dielectric properties depending on the PVA/SA concentration. The 4 wt% system showed the highest biocompatibility properties, given that its resistance and electrochemical capacitance show the formation of a mature-stage cell interaction of HGF. The EIS data offers an exhaustive analysis of the biological activity of the cell response in real time to determine its biocompatibility features. Fluorescence analysis demonstrated a heterogeneous growth of the HGF on the PVA/SA scaffold surface.
  • Effect of static magnetic field on mold corrosion of printed circuit
    • Abstract: Publication date: Available online 13 September 2019Source: BioelectrochemistryAuthor(s): Jirui Wang, Ziheng Bai, Kui Xiao, Xueming Li, Qianqian Liu, Xuan Liu, Junsheng Wu, Lin Lu, Chaofang DongMold has a strong impact on the corrosion behavior of metals, especially under environmental conditions conducive to mold growth. However, the magnetic fields generated by electronic devices have effects on the metal corrosion and mold growth. In this study, a 10 mT static magnetic field (SMF) perpendicular to the surface of samples was applied to study the corrosion of a copper-clad printed circuit board (PCB-Cu) by mold under the SMF. Based on the analysis of the corrosion morphology of the PCB-Cu after a test in the atmosphere and the composition of the corrosion products, the corrosion behavior of mold on the PCB-Cu in the presence or absence of the SMF was revealed. In the absence of a magnetic field, mold formed a spore-centered corrosion pit group on the surface of the PCB-Cu, which was macroscopically characterized by regional uniform corrosion. When a 10 mT SMF was applied, the magnetic field exhibited an inhibitory effect on the growth of mold, which was hindered, and the corrosion of the PCB-Cu surface slowed down.Graphical abstractUnlabelled Image
  • Rapid recognition and determination of tryptophan by carbon nanotubes and
           molecularly imprinted polymer-modified glassy carbon electrode
    • Abstract: Publication date: Available online 12 September 2019Source: BioelectrochemistryAuthor(s): Yiyong Wu, Peihong Deng, Yaling Tian, Ziyu Ding, Guangli Li, Jun Liu, Zavuga Zuberi, Quanguo HeA tryptophan (Trp) molecularly imprinted electrochemical sensor was fabricated by drop-coating an imprinted chitosan film on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (MIP-MWCNTs/GCE). The surface morphology and electrochemical properties of the MIP-MWCNTs/GCE were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy. The electrochemical performance of the MIP-MWCNTs/GCE with Trp showed that the signal of the oxidation current of Trp obtained with MIP-MWCNTs/GCE was significantly enhanced relative to that of the uncovered GCE, indicating that the modified electrode can accelerate electron transfer and has strong selectivity for Trp. The experimental conditions were optimized in parallel, and under the optimal conditions, the MIP-MWCNTs/GCE showed a good linear relationship between the Trp oxidation peak current and Trp concentrations in the ranges of 2.0 nM–0.2 μM, 0.2 μM–10 μM and 10 μM–100 μM The limit of detection (LOD) was 1.0 nM (S/N = 3), and the modified electrode had good reproducibility and stability. Finally, the MIP-MWCNTs/GCE was successfully applied to the determination of Trp in the human serum samples.Graphical abstractUnlabelled Image
  • Acetylcholinesterase modified AuNPs-MoS2-rGO/PI flexible film biosensor:
           Towards efficient fabrication and application in paraoxon detection
    • Abstract: Publication date: Available online 11 September 2019Source: BioelectrochemistryAuthor(s): Lingpu Jia, Yaxin Zhou, Kaipeng Wu, Qingling Feng, Chunming Wang, Ping HeA flexible acetylcholinesterase (AChE) film biosensor, based on a AuNPs-MoS2-reduced graphene oxide/polyimide flexible film (rGO/PI) electrode, has been synthesized for paraoxon detection. In this study, the rGO/PI film acts as the flexible substrate and AuNPs are reduced by monolayer MoS2 under illumination. Transmission electron microscopy revealed that AuNPs are uniformly dispersed on the MoS2-rGO/PI electrode surface with a diameter ~10 nm. X-ray photoelectron spectroscopy indicated that a strong binding force exists between reduced AuNPs and monolayer MoS2. The AChE modified AuNPs-MoS2-rGO/PI flexible film biosensor is used to hydrolyze acetylcholine chloride and obtain a large current response at 0.49 V by differential pulse voltammetry, demonstrating successful immobilization of AChE. In view of the inhibition of paraoxon on the AChE, under optimal conditions, the AChE/AuNPs-MoS2-rGO/PI film biosensor shows a linear response over a concentration range 0.005–0.150 μg/mL, a sensitivity of 4.44 uA/μg/ mL, a detection limit of 0.0014 μg/mL, acceptable reproducibility and stability to paraoxon. The flexible film biosensor has also proved used for detection of paraoxon in real samples.Graphical abstractWe constructed a paraoxon sensor based on AChE/AuNPs-MoS2-rGO/PI flexible film. In this work, the rGO/PI film acts as the flexible substrate and AuNPs are reduced by monolayer MoS2 under illumination. The AChE modified AuNPs-MoS2-rGO/PI flexible film biosensor was used to hydrolyze acetylcholine chloride and obtained a large current response at 0.49 V by differential pulse voltammetry. For paraoxon detection, the obtained AChE/AuNPs-MoS2-rGO/PI flexible film also shows good sensing property.Unlabelled Image
  • Effect of anaerobic sludge on the bioelectricity generation enhancement of
           bufferless single-chamber microbial fuel cells
    • Abstract: Publication date: Available online 11 September 2019Source: BioelectrochemistryAuthor(s): Ying Lv, Yue Wang, Yueping Ren, Xiufen Li, Xinhua Wang, Jian LiEnhancing the self-buffering capacity is critical in the operation of bufferless microbial fuel cells (BLMFCs). Inorganic carbon (IC) is an ideal endogenous buffers, but its spontaneously accumulated concentrations are insufficient to adjust anolyte pH. In this study, BLMFCs were operated with anaerobic sludge to enhance IC accumulation and increase anolyte pH. The accumulated IC concentration during a single running cycle was elevated from 8.3 mM to 12.5 mM, and anolyte pH remained above 7.5. The electric power output was significantly promoted from 332.2 mW·m−2 to 628.1 mW·m−2, and the coulombic efficiency (CE) slightly increased from 16.4% to 19.5%. Geobacter was the electro-active genus in the anode biofilms of the MFCs, and its relative abundance in the KCl-S anode biofilm increased from 0.2% to 5.75%. After continuous operation, the predominant genus of the anaerobic sludge had changed from Flavobacterium to Fusibacter.Graphical abstractUnlabelled Image
  • Gold nanocubes embedded biocompatible hybrid hydrogels for electrochemical
           detection of H2O2
    • Abstract: Publication date: Available online 7 September 2019Source: BioelectrochemistryAuthor(s): Pandiaraj Manickam, Arti Vashist, Sekar Madhu, Mohanraj Sadasivam, Arunkumar Sakthivel, Ajeet Kaushik, Madhavan NairAbstractSmart electrochemical biosensors have emerged as a promising alternative analytical diagnostic tool in recent clinical practice. However, improvement in the biocompatibility and electrical conductivity of the biosensor matrix and the immobilization of various bioactive molecules such as enzymes still remain challenging. The present research reports the synthesis of a biocompatible hydrogel network and its integration with gold nanocubes (AuNCs) for developing a novel biosensor with improved functionality. The interpenetrating hydrogel network consist of biopolymers developed using graft co-polymerization of β-cyclodextrin (β-CD) and chitosan (CS). The novelty of this work is in integrating the CS-g-β-CD hydrogel network with conductive AuNCs for improving hydrogel conductivity, biosensor sensitivity and use of the material for a biocompatible sensor. The present protocol advances the state of the art for the utilization of biopolymeric hydrogels system in synergy with an enzymatic biosensing protocol for exclusively detecting hydrogen peroxide (H2O2). Immobilization of the mitochondrial protein, cytochrome c (cyt c) into the hydrogel nanocomposite matrix was performed via thiol cross-linking. This organic-inorganic hybrid nanocomposite hydrogel matrix exhibited high biocompatibility (RAW 264.7 and N2a cell lines), improved electrical conductivity to attain high sensitivity (1.2 mA mM−1 cm−2) and a low detection limit (15 × 10−9 M) for H2O2.
  • Understanding the role of calcium-mediated cell death in high-frequency
           irreversible electroporation
    • Abstract: Publication date: Available online 6 September 2019Source: BioelectrochemistryAuthor(s): Elisa M. Wasson, Nastaran Alinezhadbalalami, Rebecca M. Brock, Irving C. Allen, Scott S. Verbridge, Rafael V. DavalosAbstractHigh-frequency irreversible electroporation (H-FIRE) is an emerging electroporation-based therapy used to ablate cancerous tissue. Treatment consists of delivering short, bipolar pulses (1–10 μs) in a series of 80–100 bursts (1 burst/s, 100 μs on-time). Reducing pulse duration leads to reduced treatment volumes compared to traditional IRE, therefore larger voltages must be applied to generate ablations comparable in size. We show that adjuvant calcium enhances ablation area in vitro for H-FIRE treatments of several pulse durations (1, 2, 5, 10 μs). Furthermore, H-FIRE treatment using 10 μs pulses delivered with 1 mM CaCl2 results in cell death thresholds (771 ± 129 V/cm) comparable to IRE thresholds without calcium (698 ± 103 V/cm). Quantifying the reversible electroporation threshold revealed that CaCl2 enhances the permeabilization of cells compared to a NaCl control. Gene expression analysis determined that CaCl2 upregulates expression of eIFB5 and 60S ribosomal subunit genes while downregulating NOX1/4, leading to increased signaling in pathways that may cause necroptosis. The opposite was found for control treatment without CaCl2 suggesting cells experience an increase in pro survival signaling. Our study is the first to identify key genes and signaling pathways responsible for differences in cell response to H-FIRE treatment with and without calcium.
  • A pyridine-Fe gel with an ultralow-loading Pt derivative as ORR catalyst
           in microbial fuel cells with long-term stability and high output voltage
    • Abstract: Publication date: Available online 4 September 2019Source: BioelectrochemistryAuthor(s): Huiqiang Wang, Liling Wei, Chaojie Yang, Jianting Liu, Jianquan ShenA low-cost and high-efficiency oxygen reduction reaction (ORR) catalyst was fabricated using a pyridine-Fe gel with ultralow-loading of Pt nanoparticles and subsequently applied to air-cathode microbial fuel cells (MFCs). This novel catalyst (N3/Fe/C-Pt) exhibited excellent electrocatalytic activity with a positive onset potential of 0.19 V (vs Ag/AgCl) and half-wave potential of 0.03 V (vs Ag/AgCl), which is comparable to commercial PtC catalysts. More importantly, N3/Fe/C-Pt shows remarkable oxygen reduction activity in MFCs with a distinct output voltage (568 mV) and power density (504 mW m−2) for 400 h when it is fed with a culture medium containing 5 g L−1 sucrose in the phosphate buffer solution. This strategy, incorporating Pt nanoparticles uniformly into a conductive gel demonstrates significance for broadening the development and research of gel-based catalysts for applications in batteries.Graphical abstractA low-cost and high-efficient oxygen reduction reaction catalyst (N3/Fe/C-Pt) is applied in an air-cathode microbial fuel cell, which is compared with the commercial Pt/C catalysts.Unlabelled Image
  • Access resistance in protein nanopores. A structure-based computational
    • Abstract: Publication date: Available online 3 September 2019Source: BioelectrochemistryAuthor(s): Marcel Aguilella-Arzo, Vicente M. AguilellaAbstractSingle-channel conductance measurements in biological pores have demonstrated the importance of interfacial effects in nanopores, particularly in protein channels with low aspect ratio (length over aperture radius). Access resistance (AR), the contribution to the total measured resistance arising from the electrodiffusive limitation that ions experience in passing from bulk solution to confinement within the pore, becomes essential in the description of ionic transport across these biological channels. Common analytical estimates of AR are based on idealized nanopore models, cylindrical in shape, electrically neutral and embedded in a neutral substrate. Here we calculate the AR of five protein channels by using their atomic structure and a mean-field approach based on solving 3D Poisson and Nernst-Planck equations. Our approach accounts for the influence of the protein charged ionizable residues, the geometry of the pore mouth and the ion concentration gradients near the pore. We compare numerical calculations with the few available AR measurements and show for several protein channels that analytical predictions tend to overestimate AR for physiological concentrations and below. We also discuss the relationship between AR and the size of the channel aperture in single-pore channels and three-pore channels and demonstrate that in the latter case, there is an enhancement of AR.
  • The preparation of hollow AgPt@Pt core-shell nanoparticles loaded on
           polypyrrole nanosheet modified electrode and its application in
    • Abstract: Publication date: Available online 29 August 2019Source: BioelectrochemistryAuthor(s): Ping Wang, Fubin Pei, Enhui Ma, Qingshan Yang, Haoxuan Yu, Jiao Liu, Yueyun Li, Qing Liu, Yunhui Dong, Hongjun ZhuThe designed synthesis of efficient materials can significantly enhance the performance of electrochemical immunoassay in the detection of diseases, pesticide residues and environmental pollutants. The hollow AgPt@Pt core-shell nanoparticles (AgPt@Pt HNs) have exhibited high catalytic efficiency to the hydrogen peroxide (H2O2) reduction for its high mass activity from their hollow structure. Their limitation of instability can be overcome by loading on polypyrrole nanosheet (PPy NS). Besides, PPy NS exhibits good conductivity, and there exists environmentally-friendly method for its synthetic. Thus, AgPt@Pt HNs loaded on PPy NS (AgPt@Pt HNs/PPy NS) exhibits high catalytic efficiency to the reduction of H2O2 and good stability. Furthermore, the quick electron transfer of AgPt@Pt HNs/PPy NS modified glassy carbon electrode has been evidenced by the finding that the large constant of apparent electron transfer rate has also enlarged the current signal when the amount of electron is invariant. The modified electrode has fabricated a label-free amperometric immunosensor to detect sensitively prostate-specific antigen (PSA) with H2O2 as the electroactive material. The immunosensor in hollow core-shell nanosheet structure exhibiting good detection performance of PSA shows its promising applications in the clinical diagnosis.Graphical abstractUnlabelled Image
  • Effective electrochemotherapy with curcumin in MDA-MB-231-human, triple
           negative breast cancer cells: A global proteomics study
    • Abstract: Publication date: Available online 22 August 2019Source: BioelectrochemistryAuthor(s): Lakshya Mittal, Uma K. Aryal, Ignacio G. Camarillo, Vishak Raman, Raji SundararajanAbstractCurcumin (Cur), the yellow pigment of well-known turmeric (Curcuma longa L.) is effective in multiple cancers including triple negative breast cancer (TNBC). In combination with electrical pulses (EP), enhanced effects of curcumin (Cur + EP) are observed in TNBC cells. To gain insights into the mechanisms of enhanced anticancer effects of Cur + EP, we studied the proteins involved in the anticancer activity of Cur + EP in MDA-MB-231, human TNBC cells using high-throughput global proteomics. A curcumin dose of 50 μM was applied with eight, 1200 V/cm, 100 μs pulses, the most commonly used electrochemotherapy (ECT) parameter in clinics. Results show that the Cur + EP treatment caused a complete inhibition of clonogenic ability in MDA-MB-231 cells, while inducing apoptosis. Proteomic analysis identified a total of 1456 proteins, of which 453 proteins were differentially regulated, including kinases, heat shock proteins, transcription factors, structural proteins, and metabolic enzymes. Eight key glycolysis proteins (ALDOA, ENO2, LDHA, LDHB, PFKP, PGM1, PGAM1 and PGK1), were downregulated in Cur + EP from Cur. There was a switch in the metabolism with upregulation of 10 oxidative phosphorylation pathway proteins and 8 tricarboxylic acid (TCA) cycle proteins in the Cur + EP sample, compared to curcumin. These results provide novel systematic insights into the mechanisms of ECT with curcumin.
  • Sulfide-mediated azo dye degradation and microbial community analysis in a
           single-chamber air cathode microbial fuel cell
    • Abstract: Publication date: Available online 22 August 2019Source: BioelectrochemistryAuthor(s): Qin Dai, Sai Zhang, Hao Liu, Jun Huang, Li LiAbstractSeveral textile industry processes produce complex organics, azo dyes and sulfide streams that pose a severe challenge to environmental protection. In this work, single-chamber air cathode microbial fuel cells were used to investigate the interaction mechanisms among Congo red decolorization, sulfide oxidation and bioelectricity generation. The results showed that effective removal of sulfide (>98%) and azo dyes (>88%) was achieved at an initial sulfide/dye ratio of 0.9 under neutral conditions, accompanied by a maximum power output of approximately 23.50 mW m−2. In this study, biogenic sulfide played a major role in azo dye decolorization and power generation compared with the chemical sulfide. The results indicated that bulk reduction of sulfide and cell lysis products during biogenic sulfide production by sulfate-reduction bacteria could accelerate the chemical reduction of azo dyes. Moreover, S0, SO42− and S2O32− were identified as degradation products, and the intermediates primarily included 3,4-diaminonaphthalene-1-sulfonic acid, sodium 4-aminonaphthalene-1-sulfonate and 4, 4′-diamine biphenyl. Microbial community analysis showed that Proteobacteria (80.7%), Gammaproteobacteria (48.1%), and Dokdonella (29.5%) dominated at the phylum, class, and genus levels, respectively, of the anodic biofilm. This study offers a feasible option for the treatment of recalcitrant organics, azo dyes and sulfide pollutants using single-chamber air cathode MFCs.
  • Multi-walled carbon nanotubes accelerate interspecies electron transfer
           between Geobacter cocultures
    • Abstract: Publication date: Available online 12 August 2019Source: BioelectrochemistryAuthor(s): Shiling Zheng, Zeng Li, Peng Zhang, Bingchen Wang, Pengyu Zhang, Yujie FengAbstractCarbon nanotubes (CNTs) have been reported to promote symbiotic metabolism in bacteria by accelerating interspecies electron transfer. However, this phenomenon has not been investigated or proven in a cocultures system. In this study, multi-walled CNTs (MWCNTs) were added into Geobacter cocultures systems with the ability of direct interspecies electron transfer (DIET). Results showed that addition of MWCNTs accelerated the metabolic rate of the cocultures. Succinate production rate in a test with 1.0 g L−1 MWCNTs was 1.12 mM d−1, 1.67 times higher than without MWCNTs. However, the biotoxicity effect became evident with the addition of much higher levels of MWCNTs addition. This study supports the possibility that carbon nanotubes accelerate interspecies electron transfer and provides a theoretical basis for the MWCNTs application in the process of anaerobic wastewater treatment.
  • High-performance electrochemical enzyme sensor for organophosphate
           pesticide detection using modified metal-organic framework sensing
    • Abstract: Publication date: Available online 9 August 2019Source: BioelectrochemistryAuthor(s): Ehsan Mahmoudi, Hanieh Fakhri, Ali Hajian, Abbas Afkhami, Hasan BagheriA practical electrochemical biosensor with high sensitivity was developed for detecting organophosphorus (OP). Initially, Ce metal was introduced into an UiO-66-template to form Ce/UiO-66. Later, graphene oxide (GO), carbon black (CB) and multi-walled carbon nanotubes (MWCNTs) were separately added to Ce/UiO-66 to compare the effect of different carbon-based material types on the performance of the biosensor. Exclusively, Ce/UiO-66/MWCNTs with a Ce (7%) and MWCNT (30%) matrix was found to not only load more acetylcholinesterase (AChE) onto vacant sites but also increase electron transfer and decrease the number of diffusion pathways between the thiocholine and electrode surface. Moreover, the appropriate oxophilicity of Ce coupled with the high surface area and good conductivity of MWCNTs in the UiO-66 structure revealed a high affinity to acetylthiocholine chloride (ATCl) and possible catalysis of the hydrolysis of ATCl with a Michaelis-Menten constant of 0.258 mM. This biosensor, under optimal conditions, demonstrated a rapid and sensitive detection of paraoxon over a wide linear range of 0.01–150 nM, with a low detection limit of 0.004 nM. As a result, the AChE/Ce/UiO-66/MWCNTs/GCE biosensor can be employed in laboratory and field experiments to determine paraoxon levels.Graphical abstractUnlabelled Image
  • A theranostic system based on nanocomposites of manganese oxide
           nanoparticles and a pH sensitive polymer: Preparation, and physicochemical
    • Abstract: Publication date: Available online 9 August 2019Source: BioelectrochemistryAuthor(s): Marzieh Samiei Foroushani, Nazanin Niroumand, Reza Karimi Shervedani, Fatemeh Yaghoobi, Amirhosein Kefayat, Mostafa TorabiAbstractA multifunctional nanocomposite theranostic system is constructed of manganese oxide (Mn3O4) nanoparticles (NPs), as a tumor diagnostic agent, in conjunction with polyacrylic acid (PAA), as a pH-sensitive drug delivery agent, and methotrexate (MTX), as a model of targeting agent and anticancer drug. Physicochemical characteristics of the Mn3O4@PAA/MTX system is studied in detail by several techniques, including X-ray and Auger photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and electrochemical methods. The system performance is studied based on (i) in-vitro MRI measurements to support efficiency of the Mn3O4@PAA NPs as a diagnostic agent, (ii) drug release performance of the Mn3O4@PAA/MTX NPs at pHs of 5.4 and 7.4 through in-vitro method to evaluate application of the NPs as pH-sensitive nanocarriers for MTX, and (iii) impedance spectroscopy measurements to show Mn3O4@PAA/MTX NPs affinity for capturing of cancer cells. The results show that (i) Mn3O4@PAA NPs can be used as a contrast agent in MRI measurements (r1 ≅ 6.5 mM−1 s−1), (ii) the MTX, loaded on Mn3O4@PAA NPs, is released faster and more efficient at pH 5.4 than 7.4, and (iii) the GC-Mn3O4@PAA/MTX electrode system captures the 4T1 cells 3.32 times larger than L929 cells.
  • Continuous autotrophic denitrification process for treating ammonium-rich
           leachate wastewater in bioelectrochemical denitrification system (BEDS)
    • Abstract: Publication date: Available online 7 August 2019Source: BioelectrochemistryAuthor(s): Sanath Kondaveeti, Eunha Kang, Hong Liu, Booki MinAbstractThe reduction of nitrogen compounds in aqueous solution is extremely important for sustainable management of ecosystem and human health. An autotrophic bioelectrochemical denitrification (BED) process was evaluated at various conditions for enhanced treatment of synthetic wastewater (SW) and ammonium-rich leachate. With SW, a decrease in hydraulic retention time (HRT: 41.6 to 8.3 h) resulted in a 370% increase in denitrification rate from 0.026 to 0.096 kg NO3−N/m3. D. An increase in applied voltage (0.7 to 2 V) enhanced nitrate removal (81 to 97% removal), but coulombic efficiency decreased from 74% to 19%. With doubled cathode electrodes, the nitrate removal rate was doubled from 0.056 to 0.114 kg NO3−N/m3. D. Moreover, leachate wastewater was successfully denitrified with the maximum removal rate of 0.121 kg NO3−N/m3. D. These results point towards the practical potential for the combination of nitrification systems with BEDS for reduction of nitrogen for discharge purposes.
  • Cellobiose dehydrogenase: Bioelectrochemical insights and applications
    • Abstract: Publication date: Available online 3 August 2019Source: BioelectrochemistryAuthor(s): Stefan Scheiblbrandner, Roland LudwigCellobiose dehydrogenase (CDH) is a flavocytochrome with a history of bioelectrochemical research dating back to 1992. During the years, it has been shown to be capable of mediated electron transfer (MET) and direct electron transfer (DET) to a variety of electrodes. This versatility of CDH originates from the separation of the catalytic flavodehydrogenase domain and the electron transferring cytochrome domain. This uncoupling of the catalytic reaction from the electron transfer process allows the application of CDH on many different electrode materials and surfaces, where it shows robust DET. Recent X-ray diffraction and small angle scattering studies provided insights into the structure of CDH and its domain mobility, which can change between a closed-state and an open-state conformation. This structural information verifies the electron transfer mechanism of CDH that was initially established by bioelectrochemical methods. A combination of DET and MET experiments has been used to investigate the catalytic mechanism and the electron transfer process of CDH and to deduce a protein structure comprising of mobile domains. Even more, electrochemical methods have been used to study the redox potentials of the FAD and the haem b cofactors of CDH or the electron transfer rates. These electrochemical experiments, their results and the application of the characterised CDHs in biosensors, biofuel cells and biosupercapacitors are combined with biochemical and structural data to provide a thorough overview on CDH as versatile bioelectrocatalyst.Graphical abstractUnlabelled Image
  • Effect of isoelectric point on cheese whey wastewater treatment using a
           microbial electrochemical system
    • Abstract: Publication date: December 2019Source: Bioelectrochemistry, Volume 130Author(s): Batoul Mohebrad, Abbas Rezaee, Beheshteh SohrabiAbstractIn this study, a microbial electrochemical system (MES) was employed to investigate the effect of isoelectric point (IEP) on cheese whey wastewater treatment. The experiments were carried out in a bioreactor equipped with a semicircular carbon cloth and stainless steel electrodes as anode and cathode, respectively. The effects of IEP, whey protein concentration, electrical current, and time were studied. The IEP of the whey protein was determined at pH 5.9. The optimum electrical current was obtained at 6 mA for synthetic cheese whey wastewater. The results of rotary exponential doping showed that the third structure of proteins chenges to the second structure at the IEP. The highest protein removal (98%) was obtained at pH 6. The results showed that 76%, 83%, and 98% protein removal were achieved at 2, 4, and 8 h, respectively.
  • A boronic acid carbon nanodots/poly(thionine) sensing platform for the
           accurate and reliable detection of NADH
    • Abstract: Publication date: Available online 2 August 2019Source: BioelectrochemistryAuthor(s): Xueyan Li, Xianwen KanIn this work, a novel electrochemical sensing platform was designed and fabricated by the modification of boronic acid functionalized carbon nanodots (B-CNDs) and poly(thionine) (pTHI) on an electrode surface. B-CNDs can not only accelerate electron transfer but also covalently interact with cis-diol groups of dihydronicotinamide adenine dinucleotide (NADH) through functionalized boronic acid groups. Meanwhile, pTHI served as an inner reference element to provide a built-in correction, which enabled the sensor to detect NADH with high accuracy and reliability based on a ratiometric signal (∆INADH/∆ITHI). The electrochemical experimental results demonstrated that the ratiometric strategy-based sensor possessed good selectivity and high sensitivity. A linear range of 5.0 × 10−7 - 2.0 × 10−4 mol/L for NADH detection was obtained with a limit of detection of 1.5 × 10−7 mol/L. The sensor has been applied to analyze NADH in human serum samples with satisfactory results. The simple and effective ratiometric strategy reported here can be further used to prepare electrochemical sensors for selective, sensitive, and reliable detection of other cis-diol compounds.Graphical abstractUnlabelled Image
  • Electrotransfer of CpG free plasmids enhances gene expression in skin
    • Abstract: Publication date: Available online 1 August 2019Source: BioelectrochemistryAuthor(s): S. Chabot, E. Bellard, J.P. Reynes, G. Tiraby, J. Teissie, M. GolzioAbstractSkin is a very suitable target for gene therapy and DNA vaccination due to its accessibility, its surface and its ability to produce transgenes. Gene electrotransfer (GET) to the skin is under development for clinical applications for DNA vaccine or local treatment such as wound healing. Local treatments are effective if the expression of the plasmid affects only the local environment (skin) by inducing an efficient concentration over a prolonged period. In this study, we evaluate the control of expression in the skin of a plasmid coding a fluorescent protein by its CpG (cytosine–phosphate–guanine motif) content. Two fluorescent reporter genes are evaluated: tdTomato and GFP. The expression is followed on the long term by in vivo fluorescence imaging. Our results show that GET mediated expression in the skin can be controlled by the CpG content of the plasmid. Long term expression (>120 days) can be obtained at high level with CpG-free constructs associated with a proper design of the electrodes where the field distribution mediating the gene electrotransfer is present deep in the skin.
  • Effect of electroporation and recovery medium pH on cell membrane
           permeabilization, cell survival and gene transfer efficiency in vitro
    • Abstract: Publication date: Available online 1 August 2019Source: BioelectrochemistryAuthor(s): Tjaša Potočnik, Damijan Miklavčič, Alenka Maček LebarAbstractElectroporation is a method which uses an adequate number of electric pulses of enough amplitude, duration and number applied to cells, thus inducing transient permeabilization of the cell membrane. Due to possibility that microenvironment in applications of in vivo electroporation is slightly acidic, we studied the effects of slightly acidic electroporation and recovery medium. We observed no difference in the permeabilization threshold, detected by propidium iodide, of cells which were electroporated and allowed to recover in growth (pH 7.8) or acidic (pH 6.5) medium. In contrast, statistically significant difference was observed in survival of cells that were exposed to pulse amplitudes greater than permeabilization threshold. Survival of cells was greater if acidic electroporation and recovery medium were used, but acidic extracellular pH decreased gene electrotransfer efficiency. We also observed differences in morphology between cells that were electroporated and left to recover in growth medium and cells that were electroporated and left to recover in acidic medium. Our results imply that slightly acidic extracellular pH allows more efficient repair of damage that is induced on cell membrane during electroporation with high pulse amplitudes.
  • Highly sensitive electrochemical analysis of telomerase activity based on
           magnetic bead separation and exonuclease III-aided target recycling
    • Abstract: Publication date: Available online 31 July 2019Source: BioelectrochemistryAuthor(s): Jinlong Li, Jiehua Ma, Yongchen Zhang, Zhaoli Zhang, Kai HuTelomerase is considered a pivotal biomarker for early cancer diagnosis and a valuable therapeutic target. However, the current methods to detect telomerase activity have some limitations. Herein, we propose a homogeneous electrochemical strategy to develop a simple, rapid, and highly sensitive assay to detect human telomerase activity from crude cancer cell extracts. Our strategy is based on magnetic bead separation and exonuclease III-aided target recycling amplification. The complementary probes can hybridize with the extended telomeric repeats, which allows exonuclease III to recognize and digest the latter once the hybrid product is separated with magnetic beads. The released complementary probes can hybridize with and open multiple methylene blue (MB)-labeled hairpin (HP) DNA probes, allowing exonuclease III to digest the duplex. Then, the opened hairpin couples with the captured mononucleotides on the surface of the gold electrode. By taking advantage of the exonuclease III-aided target recycling strategy, the present assay enables the detection of telomerase activity at a single-cell level. Furthermore, the assay is carried out in a homogeneous solution achieved by magnetic purification, which removes the interferents present in crude lysates and avoids false negatives, thus, providing a powerful platform to detect telomerase activity in samples of early-stage cancer.Graphical abstractUnlabelled Image
  • Green Eucalyptus leaf extract: A potent source of bio-active corrosion
           inhibitors for mild steel
    • Abstract: Publication date: Available online 27 July 2019Source: BioelectrochemistryAuthor(s): Ali Dehghani, Ghasem Bahlakeh, Bahram RamezanzadehEucalyptus leaves extract (ELE) inhibition impact toward mild steel (MS) corrosion in the HCl solution was examined by combined experimental and computational studies. The degree of inhibition was investigated by EIS and polarization test. The EIS analysis results showed that the increase of ELE concentration led to the significant increment of charge transfer resistance. An inhibition efficiency of ~88% was obtained using 800 ppm ELE after 5 h exposure. Polarization test results indicated the mixed inhibition effects of ELE with slight cathodic prevalence. The icorr values for the uninhibited and inhibited (800 ppm ELE) samples were 0.93 μA/cm2 and 0.25 μA/cm2, respectively. The ELE molecules adsorption on the surface of MS followed a Langmuir isotherm. Furthermore, the molecular simulation results evidenced the adsorption of ELE compounds on the iron surface.Graphical abstractUnlabelled Image
  • Mechanisms of enhanced bacterial endospore inactivation during
           sterilization by ohmic heating
    • Abstract: Publication date: Available online 26 July 2019Source: BioelectrochemistryAuthor(s): Felix Schottroff, Taras Pyatkovskyy, Kai Reineke, Peter Setlow, Sudhir K. Sastry, Henry JaegerAbstractDuring ohmic heating, the electric field may additionally inactivate bacterial endospores. However, the exact mechanism of action is unclear. Thus, a mechanistic study was carried out, investigating the possible target of electric fields inside the spore. Bacillus subtilis spores were heated by conventional and ohmic heating in a capillary system under almost identical thermal conditions. Wild-type (PS533) spores were used, as well as isogenic mutants lacking certain components known for their contribution to spores' heat resistance: small-acid soluble proteins (SASP) protecting DNA (PS578); the coat covering the spore (PS3328); and the spore germination enzyme SleB (FB122(+)). Treatment-dependent release of the spore core's depot of dipicolinic acid (DPA) was further evaluated. Up to 2.4 log10 additional inactivation of PS533 could be achieved by ohmic heating, compared to conventional heating. The difference varied for the mutants, with a decreasing difference indicating a decreased effect of the electric field and vice versa. In particular, mutant spores lacking SASPs showed a behavior more similar to thermal inactivation alone. The combination of heat and electric field was shown to be necessary for enhanced spore inactivation. Thus, it is hypothesized that either the heat treatment makes the spore susceptible to the electric field, or vice versa.
  • Direct electrochemistry of bacterial surface displayed cytokinin oxidase
           and its application in the sensitive electrochemical detection of
    • Abstract: Publication date: Available online 25 July 2019Source: BioelectrochemistryAuthor(s): Yong Li, Bin Gong, Xiaosheng Liang, Yunhua WuAbstractCytokinin oxidase from Nipponbare (OsCKX4) was successfully displayed on the surface of E. coli cells by an ice nucleation protein from Pseudomonas borealis DL7 as an anchoring motif and a maltodextrin-binding protein(MBP) from E. coli as a solubility enhancer. The OsCKX4-displayed bacteria can be directly immobilized onto an electrode to selectively detect cytokinins, thus eliminating the need for enzyme extraction and purification. Direct electrochemistry of the cofactor FADH2 in OsCKX4 has been achieved on an edge-plane pyrolytic graphite electrode (PGE) with a formal potential (E0’) of −0.45 V at pH 7.0 in phosphate buffer. With the addition of isopentenyladenine, the reduction peak current for FADH2 decreased, and the oxidative peak current increased gradually. Therefore, a bacteria-OsCKX4-modified PGE has been developed for the detection of isopentenyladenine with a linear range of 1.0–11.0 μM and a lower limit of detection of 0.7 μM (S/N = 3). Slight interference was observed in the presence of other phytohormones, including brassinosteroid, abscisic acid, methylene jasminate and gibberellin. The proposed bacterial biosensor is stable, specific and simple and has great potential for applications that require the detection of cytokinins.
  • Effect of electrode geometry on the electrolyte resistance measurement
           over the surface of a skin phantom in a noninvasive manner
    • Abstract: Publication date: Available online 24 July 2019Source: BioelectrochemistryAuthor(s): Humberto F. Delgado-Arenas, Aarón Rodríguez-López, Fernando Rivera, Karen J. Ramos, Rubí Reséndiz-Ramírez, Rene Antano-LopezAbstractWe analyzed the electrode geometry to obtain the potential (E) and current density (J) distributions at the surface of a skin phantom (SP), in this case a planar surface. Two electrode geometries were tested: a circular electrode (CiE) and a rectangular electrode (ReE). First, by a finite element simulation, we calculated the E and J distributions at the surface of the SP. Second, we determined the resistivity properties as a function of the electrochemical impedance. Three- and four-electrode configurations were used to measure the E versus distance between the reference electrodes (d). For the ReE, the electrolyte resistance (Re) measurements show a linear behavior with respect to “d” if the zone of the linear distribution of E and the homogeneous current density (JH) is considered. In contrast, the CiE shows nonlinear behavior due to the absence of that zone of the linear distribution of E and JH in the entire range. For ReE, we deduced that the behavior of Re versus “d” is related to the material resistivity. Consequently, the ReE geometry improves the Re measurements on the surface and shows us a way to control the behavior of this element in planar samples such as skin.
  • Improved performance of microbial fuel cells using a gradient porous air
           cathode: An experiment and simulation study
    • Abstract: Publication date: Available online 23 July 2019Source: BioelectrochemistryAuthor(s): Jun Li, Wei Yang, Yingying Dong, Qiang Liao, Qian Fu, Biao Zhang, Xun Zhu, Zhongliang Liu, Hang GuoAbstractHigh carbon catalyst loadings are commonly used for the catalyst layer (CL) in air-cathodes to obtain a performance comparable with that using platinum. This results in a much thicker CL, which severely limits mass transfer. In this study, we developed a porosity-gradient CL to passively enhance mass transfer in the air-cathode of microbial fuel cells (MFCs) for the first time. Computational results demonstrated that a cathode CL with increasing porosity (CL-IP) and decreasing porosity (CL-DP) from the water to the air-facing side exhibited improved transport of oxygen and OH−, respectively, alleviating concentration overpotentials in the CL. Experimental results also showed that an MFC that included a cathode with CL-IP achieved a maximum power density of 1781 ± 92 mW m−2, which was higher than that achieved with CL-DP and a homogeneous CL (1614 ± 72 and 1183 ± 205 mW m−2).
  • Identification of Clostridium cochlearium as an electroactive
           microorganism from the mouse gut microbiome
    • Abstract: Publication date: Available online 20 July 2019Source: BioelectrochemistryAuthor(s): Laura Schwab, Laura Rago, Christin Koch, Falk HarnischMicrobial electroactivity, the metabolically relevant transfer of electrons between microorganisms and solid conductors, was first discovered for now well characterized model organisms from hypoxic or anaerobic water or sediment samples. Recent findings indicate that the metabolic trait of electroactivity might as well be important within the microbiome of the mammalian gut. Based on a pre-selection from the mouse intestinal bacterial collection five microorganisms originating from diverse parts of the gut were screened for electroactivity. As there is no marker gene for electroactivity, the ability to synthesize cytochromes and metabolize redox-mediators was studied in-silico. Clostridium cochlearium showed highest electroactivity and Lactobacillus reuteri as well as Staphylococcus xylosus show putative electroactivity, as well. The maximum current density of C. cochlearium of 0.53 ± 0.02 mA cm−2 after only 5.2 h of incubation was clearly linked to growth and glucose consumption. Cyclic voltammetric analysis on C. cochlearium revealed a formal potential of the extracellular electron transfer (EET) of +0.22 ± 0.05 V versus Ag/AgCl sat. KCl (and + 0.419 V versus SHE) and indicates that EET is not based on biofilm formation, but the involvement of either redox-active molecules or planktonic cells. The potential of the gut as habitat for electroactives and their physiological role are discussed.Graphical abstractUnlabelled Image
  • Microbial electrochemical system for the phenol degradation using
           alternating current: Metabolic pathway study
    • Abstract: Publication date: December 2019Source: Bioelectrochemistry, Volume 130Author(s): Zohreh Moghiseh, Abbas Rezaee, Somayyeh Dehghani, Ali EsrafiliThe present study was conducted to investigate the effect of alternating current (AC) on phenol removal in a microbial electrochemical system (MES) and determine its by-products. The bioreactor used for this purpose operates in the batch mode supplied with an AC power supply. The factors stimulating this process including frequency, applied voltage, duty cycle, carbon to nitrogen ratio, and the initial phenol concentration were investigated. The optimum operating conditions of the bioreactor were obtained at 5 Hz frequency, 0.4 peak-to-peak voltage (Vpp), C0 = 100 mg.L−1 phenol, pH = 7, C/N = 1, and the sine wave. Phenol was completely degraded under the optimum operating conditions for 2 h. The GC–MS analysis showed the presence of carboxylic acid, oxalic acid, and propionic acid. It was observed that the generated by-products are non-toxic and phenol is completely removed to nontoxic compounds. The results show that under optimum conditions, using an alternating current, the proposed system generated low-hazard byproducts with a low energy consumption.Graphical abstractUnlabelled Image
  • Bioinspired architecture of a hybrid bifunctional enzymatic/organic
           electrocatalyst for complete ethanol oxidation
    • Abstract: Publication date: Available online 19 July 2019Source: BioelectrochemistryAuthor(s): Jefferson Honorio Franco, Paula Zaghetto de Almeida, Sofiene Abdellaoui, David P. Hickey, Pietro Ciancaglini, Maria de Lourdes T. M. Polizeli, Shelley D. Minteer, Adalgisa R. de AndradeElectrochemical ethanol oxidation was performed at an innovative hybrid architecture electrode containing TEMPO-modified linear poly(ethylenimine) (LPEI) and oxalate oxidase (OxOx) immobilized on carboxylated multi-walled carbon nanotubes (MWCNT-COOH). On the basis of chromatographic results, the catalytic hybrid electrode system completely oxidized ethanol to CO2 after 12 h of electrolysis. The fact that the developed system can catalyze ethanol electrooxidation at a carbon electrode confirms that organic oxidation catalysts combined with enzymatic catalysts allow up to 12 electrons to be collected per fuel molecule. The Faradaic efficiency of the hybrid system investigated herein lies above 87%. The combination of OxOx with TEMPO-LPEI to obtain a novel hybrid anode to oxidize ethanol to carbon dioxide constitutes a simple methodology with useful application in the development of enzymatic biofuel cells.Graphical abstractUnlabelled Image
  • Electro-fermentation and redox mediators enhance glucose conversion into
           butyric acid with mixed microbial cultures
    • Abstract: Publication date: Available online 18 July 2019Source: BioelectrochemistryAuthor(s): Paola Paiano, Miriam Menini, Marco Zeppilli, Mauro Majone, Marianna VillanoAbstractElectro-fermentation (EF) is an emerging and promising technology consisting in the use of a polarized electrode to control the spectrum of products deriving from anaerobic bioprocesses. Here, the effect of electrode polarization on the fermentation of glucose has been studied with two mixed microbial cultures, both in the absence and in the presence of exogenous redox mediators, to verify the viability of the proposed approach under a broader and previously unexplored range of operating conditions. In unmediated experiments, EF (with the cathode polarized at −700 mV vs. SHE, Standard Hydrogen Electrode) caused an increase in the yield of butyric acid production provided that glucose was consumed along with its own fermentation products (i.e. acetic acid and ethanol). The maximum obtained yield accounted for 0.60 mol mol−1.Mediated experiments were performed with Neutral Red or AQDS at a concentration of 500 μM both in the absence and in the presence of the electrode polarized at −700 mV or − 300 mV vs. SHE, respectively. Mediators showed a high selectivity towards the generation of n-butyric acid isomer from the condensation of acetate and ethanol, hence suggesting that they provided microbial cells with the required reducing power otherwise deriving from glucose in unmediated experiments.
  • Detailed characterization of Phellodendron chinense Schneid and its
           application in the corrosion inhibition of carbon steel in acidic media
    • Abstract: Publication date: Available online 15 July 2019Source: BioelectrochemistryAuthor(s): Tao He, Wilfred Emori, Run-Hua Zhang, Peter C. Okafor, Min Yang, Chun-Ru ChengWe present a combined experimental and theoretical study of the effective corrosion protection of carbon steel in 1 M HCl solution by Phellodendron chinense Schneid (PCS) bark extract. Fourier-transform infrared spectroscopy (FTIR) and liquid chromatography tandem multi-stage mass spectrometry (LC-MSn) were employed for the extract characterization. The properties of PCS as a corrosion inhibitor were evaluated by electrochemical and gravimetric experiments. Quantum chemical calculation was used to describe the electronic and adsorption properties of the identified and characterized compounds found in the extract while molecular dynamics simulation was employed to predict the equilibrium configurations and binding energies of the compounds on the steel surface. The electrochemical results revealed that PCS acted as a mixed-type corrosion inhibitor whose efficiency increased with the extract concentration but slightly decreased with increasing temperature. Quantum chemical parameters, such as the energy difference (ΔE) and the number of transferred electrons (ΔN), were used to predict the contribution of each characterized compound to the inhibition process while molecular dynamics simulation predicted parallel orientations for the configuration of the compounds and high binding energies on the metal substrate.Graphical abstractUnlabelled Image
  • Chitin biomass powered microbial fuel cell for electricity production
           using halophilic Bacillus circulans BBL03 isolated from sea salt
           harvesting area
    • Abstract: Publication date: Available online 11 July 2019Source: BioelectrochemistryAuthor(s): Ranjit Gurav, Shashi Kant Bhatia, Tae-Rim Choi, Hye-Rim Jung, Soo-Yeon Yang, Hun-Suk Song, Ye-Lim Park, Yeong-Hoon Han, Jun-Young Park, Yun-Gon Kim, Kwon-Young Choi, Yung-Hun YangIncessant depletion of non-renewable energy sources has gained attention to search for new biological systems to transform organic biomass into electricity using microbial fuel cell (MFC). The main approach of the existing study was to develop a single step process to produce electrical energy from underutilized chitin biomass. Halophilic bacterium Bacillus circulans BBL03 isolated from anodic biofilm showed higher electricity production (26.508 μAcm2) in a natural seawater medium fed with 1.0% chitin. Maximum chitinase activity (94.24 ± 4.2 U mL−1) and N-acetylglucosamine (GlcNAc) production (136.30 ± 2.8 mg g−1 chitin) were achieved at 48 h. Prominent metabolites detected in chitin hydrolysis were lactate, formate, acetate, propionate, and butyrate. Furthermore, cyclic voltammetry (CV) studies revealed the possibility of direct electron transfer by anodic biofilm to anode without any external redox mediators. Polarization and coulombic efficiency (CE) analysis showed maximum power density (PD) 1.742 mWcm2 and 47% CE using 1% chitin as a substrate. Alteration in crystallinity and functional group on chitin were analysed using FTIR and XRD. Therefore, natural seawater-chitin powered MFCs could be a cheap asset for longer electricity production.Graphical abstractUnlabelled Image
  • Electrochemical xanthine detection by enzymatic method based on Ag doped
           ZnO nanoparticles by using polypyrrole
    • Abstract: Publication date: Available online 9 July 2019Source: BioelectrochemistryAuthor(s): Buket Yalcin Sahyar, Merve Kaplan, Mehmet Ozsoz, Erdal Celik, Semih OtlesA sensitive electrochemical detection of xanthine (X), which is an early biomarker of fish meat spoilage, was achieved by a novel biosensor developed via three main steps. The first step is the electropolymerization of a conducting polymer (pyrrole) onto the pencil graphite electrode (PGE). The second step is the entrapment of silver-doped zinc oxide nanoparticles (nano Ag–ZnO) onto PGE, which has already been doped with polypyrrole (PPy). The third step is the immobilization of the enzyme (xanthine oxidase) onto the modified electrode (nano Ag–ZnO/PPy/PGE) surface. The biosensor was characterized by scanning electron microscopy (SEM). The addition of Ag-doped ZnO nanoparticles into the conducting polymer structure played an important role in the performance of the biosensor by increasing the porous structure of the conducting polymer surface. The electrochemical behaviour of the biosensor was studied by electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). This enzyme biosensor showed the maximum response at pH 7.40 when +0.7 V was applied to reach 95% of steady-state current at ~3.2 s. The designed biosensor showed high selectivity with a sensitivity of 0.03 μA/mM and a low detection limit of 0.07 μM.Graphical abstractUnlabelled Image
  • Spectro-electrochemistry of ciprofloxacin and probing its interaction with
           bovine serum albumin
    • Abstract: Publication date: Available online 9 July 2019Source: BioelectrochemistryAuthor(s): Priyanka R. Ipte, Srikant Sahoo, A.K. SatpatiIn the present investigation the electrochemical behaviour of the drug, Ciprofloxacin (Cf) and its interaction with the Bovine Serum Albumin (BSA) is reported. UV-Visible Spectroscopy (UV-Vis) and Spectro-electrochemical measurements were carried out to quantify the charge transfer process in Cf. Analysis of the results obtained from cyclic voltammetry (CV) measurements indicated the electrochemical oxidation of Cf followed mixed adsorption and diffusion control process. The spectro-electrochemical investigations were carried out and the modification of the spectral peaks were monitored to obtain the mechanism of the electrochemical oxidation process of Cf. Interaction of Cf with Bovine Serum Albumin (BSA) were investigated using electrochemical, spectroscopic and spectro-electrochemical experiments. Important electro-kinetic parameters like; the electron transfer property, binding constant and diffusivity of the Cf/BSA complex were investigated. Electrochemistry with an ultra-microelectrode was utilised to investigate the diffusivity of the drug and its complex with BSA, which supports the strong binding of Cf with BSA.Graphical abstractUnlabelled Image
  • Electroporation-induced changes in tumor vasculature and microenvironment
           can promote the delivery and increase the efficacy of sorafenib
    • Abstract: Publication date: Available online 6 July 2019Source: BioelectrochemistryAuthor(s): Hiroshi Kodama, Yosef Shamay, Yasushi Kimura, Janki Shah, Stephen B. Solomon, Daniel Heller, Govindarajan SrimathveeravalliAbstractBlood vessels, the extracellular space, and the cell membrane represent physiologic barriers to nanoparticle-based drug delivery for cancer therapy. We demonstrate that electroporation (EP) can assist in the delivery of dye stabilized sorafenib nanoparticles (SFB-IR783) by increasing the permeability of endothelial monolayers, improving diffusion through the extracellular space in tumorspheres, and by disrupting plasma membrane function in cancer cells. These changes occur in a dose-dependent fashion, increasing proportionally with electric field strength. Cell death from irreversible electroporation (IRE) was observed to contribute to the persistent transport of SFB-IR783 through these physiologic barriers. In a model of mice bearing bilateral xenograft HCT116 colorectal tumors, treatment with EP resulted in the immediate and increased uptake of SFB-IR783 when compared with the untreated contralateral tumor. The uptake of SFB-IR783 was independent of direct transfection of cells through EP and was mediated by changes in vascular permeability and extracellular diffusion. The combination of EP and SFB-IR783 was observed to result in 40% reduction in mean tumor diameter when compared with sham treatment (p 
  • Influence of a polymer membrane on the electrochemical determination of
           insulin in nanomodified screen printed carbon electrodes
    • Abstract: Publication date: Available online 29 June 2019Source: BioelectrochemistryAuthor(s): Ivana Šišoláková, Jana Hovancová, Renáta Oriňaková, Andrej Oriňak, Libuše Trnková, Daniel Rueda Garcia, Jozef RadoňákAbstractDiabetes mellitus can be considered one of the most widespread diseases globally. Hence, the diabetes research is currently focused on developing an effective, low-cost sensor having high stability and suitable analytical characteristics. Screen printed carbon electrodes (SPCEs) embody ideal candidates for insulin determination due to the small area of the working electrode eliminating the solution volume required for the given purpose. Modification of SPCEs by using nanoparticles resulted in an increase of the working electrode surface area and formation of a higher number of active species. The aim of this paper is to examine the impact of a chitosan membrane on the electrochemical determination of insulin on NiO nanoparticles (NiONPs) and multi-walled nanotube (MWCNTs) modified SPCE (NiONPs/MWCNTs/SPCE). This study is primarily conceived to compare the analytical characteristics and stability of NiONPs/chitosan-MWCNTs/SPCE and NiONPs/MWCNTs/SPCE. An electrode modified with chitosan displays a wider linear range, one of 0.25 μM - 5 μM (R2 0.997); a lower limit of detection, 94 nM; a high sensitivity (0.021 μA/μM) and better stability than that of an electrode without chitosan. According to these characteristics, the polymer is considered a necessary compound of the electrochemical insulin sensor, improving the sensor's analytical characteristics.
  • Platinized carbon fiber-based glucose microbiosensor designed for
           metabolic studies in brain slices
    • Abstract: Publication date: Available online 28 June 2019Source: BioelectrochemistryAuthor(s): Cátia F. Lourenço, Miguel Caetano, Ana Ledo, Rui M. BarbosaAbstractIn order to understand how energy metabolism adapts to changes in neuronal activity it is imperative to perform direct measurements of the flux of glucose (and other metabolites) in brain tissue. Metabolic studies using brain slice preparations are attractive due to the controllability of recording conditions, absence of anesthetic interference and refined animal experimental protocols. In this work, taking advantage of the small size and versatility of carbon fiber microelectrodes (CFMs), we aimed to develop an amperometric glucose microbiosensor suitable for glucose measurement in brain slices. Potentiostatic- or galvanostatic-driven platinum electrodeposition was used to improve the analytical properties of CFMs towards detection of hydrogen peroxide. The platinized CFMs served as platform for the development of glucose microbiosensors through the immobilization of glucose-oxidase (GOx) by cross-linking with glutaraldehyde in the presence of BSA. Selective glucose measurements were attained by modifying the electrode with a permselective layer of meta-phenylenediamine and by integrating a null sensor. The in vitro characterization studies support the good analytical features of the CFM/Pt-based microbiosensors to reliably measure glucose in brain tissue. The ex vivo experiments in rodent hippocampal slices validated their suitability to measure evoked changes in extracellular glucose. This approach, encompassing the use of null sensor to cross-check the selectivity on a moment-to-moment basis, allowed us to provide the temporal and quantitative profile of extracellular glucose changes in hippocampal slices following a spreading depolarization event.Overall, these results support the potential of these microbiosensors to be used as a valuable tool to investigate the complex nature of glucose utilization in brain tissue linked to neuronal activation both in physiological and pathological conditions.
  • Electroanalytical properties of chlorophenol red at disposable carbon
           electrodes: Implications for Escherichia coli detection
    • Abstract: Publication date: Available online 28 June 2019Source: BioelectrochemistryAuthor(s): Charnete Casimero, Teri Bigham, Ruairi J. McGlynn, James S.G. Dooley, Nigel G. Ternan, William J. Snelling, Megan E. Critchley, Cameron L. Zinkel, Robert B. Smith, Lyda P. Sabogal-Paz, James DavisThe use of coliforms and Escherichia coli as indicator species for assessing the quality of water is well established and a large variety of methods based on β-galactosidase (B-GAL) activity, inherent to the microbes within this classification, have arisen to enable their detection and enumeration. Chlorophenol red (CPR) is widely used as a chromogenic label, but its capacity for translation to electroanalytical devices has yet to be fully explored. The CPR moiety is capable of undergoing oxidation at carbon substrates (+0.7 V) giving rise to a variety of phenolic intermediates. Electrochemical, XPS and enzymatic techniques were employed to characterise the underpinning chemistry and the intermediate identified as a 1,2-quinone derivative in which the chlorine substituent is retained. The latter was found to accumulate at the electrode and, in contrast to the parent CPR, was found to be detected at a significantly less positive potential (+0.3 V). Bacterial hydrolysis of a CPR labelled substrate was demonstrated with the 1,2-quinone oxidation product found to accumulate at the electrode and detected using square wave voltammetry. Proof of concept for the efficacy of the alternative electrode pathway was established through the detection of E.coli after an incubation time of 2.5 h with no interference from the labelled substrates.Graphical abstractUnlabelled Image
  • A novel impedance enhancer for amperometric biosensor based ultrasensitive
           detection of matrix metalloproteinase-2
    • Abstract: Publication date: Available online 27 June 2019Source: BioelectrochemistryAuthor(s): Huiqiang Wang, Zhanfang Ma, Hongliang HanThe detection range and sensitivity is crucial to the determination of tumor markers. For amperometric biosensors, the detection range relies on the initial current signals (I0) and the sensitivity is tightly related to the current signals difference (ΔI) caused by per unit concentration target. Herein, an amperometric biosensor was fabricated using polyaniline gel as substrate and CS-AuNPs-Pb2+ as impedance enhancer. The sensing substrate exhibited strong current signal in [Fe(CN)6]3−/4- due to the excellent conductivity and large specific surface area of polyaniline gel. CS-AuNPs-Pb2+ with large hindrance effect can significantly increase interfacial resistance, resulting in the enhancement of ΔI. In addition, Pb2+ can react with sodium tartrate to produce non-conducting sodium tartrate gel on sensing interface, leading to further amplification of ΔI. Matrix metalloproteinase-2 (MMP-2) was analysed to prove the feasibility of this strategy. The proposed amperometric biosensor reveal both wide linear detection range from 1 pg mL−1 to 1 μg mL−1 and high sensitivity of 28.4 μA·(LgCMMP-2)−1. Therefore, this strategy will be of great significance to design other ultrasensitive amperometric biosensors.Graphical abstractUnlabelled Image
  • A hydrophobin-based-biosensor layered by an immobilized lactate
           dehydrogenase enzyme for electrochemical determination of pyruvate
    • Abstract: Publication date: Available online 26 June 2019Source: BioelectrochemistryAuthor(s): Fatemeh Mirzaei, Mohammad Mirzaei, Masoud Torkzadeh-MahaniAppropriate enzyme immobilization on the electrode surface in order to access its active site has always been an important strategy for electrode modification. In this report, lactate dehydrogenase enzyme was appropriately immobilized on the glassy carbon electrode via hydrophobin (HFB1) and graphene oxide nanocomposite. The step-by-step modification was successfully confirmed by water contact analysis, cyclic voltammetry, and electrochemical impedance spectroscopy. Under optimum conditions, this biosensor demonstrated a detection limit of 8.69 nM and RSD of 4.3% and 3.6% (n = 5) for reproducibility and repeatability. The effect of scan rate on the oxidation behavior of NADH was investigated by cyclic voltammetry; and diffusion coefficient for NADH was estimated at 6.27 × 10−8 cm2.s−1. The apparent Michaelis–Menten constant (Kmapp) was amperometrically determined and it was lower than Kmapp for the free enzyme. Also, the modified electrode represented good stability after nine days with 6% decrease in current. The proposed assay was successfully used in real sample-serum-analysis and the obtained recoveries were between 93% and 104.0%.Graphical abstractUnlabelled Image
  • Electrochemical aptasensor for activated protein C using a gold
           nanoparticle – Chitosan/graphene paste modified carbon paste electrode
    • Abstract: Publication date: Available online 25 June 2019Source: BioelectrochemistryAuthor(s): Maryam Hosseini Ghalehno, Mohammad Mirzaei, Masoud Torkzadeh-MahaniAbstractIn this work, a selective and simple electrochemical aptasensor was developed for the detection of activated protein C by employing methylene blue (MB) as a redox indicator. An activated protein C aptamer (APC-apt) was covalently immobilized on the surface of a carbon paste electrode modified with gold nanoparticle – chitosan /graphene paste (AuNPs-Chi/Gr). The AuNPs-Chi/Gr paste increased electrochemical peak current and immobilized the aptamer on the electrode surface. The process of aptasensor construction and successful immobilization of the aptamer on the electrode surface was confirmed by electrochemical cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was used to determine the methylene blue peak current. By replacing APC instead of MB at the electrode surface, the cathodic current of the MB decreases, and this decrease corresponds to the APC concentration. Under optimum conditions, the APC concentration was detected in the range from of 0.1 ng·mL−1 to 40 μg·mL−1 with a relatively low detection limit of 0.073 ng·mL−1. This method was then applied to the determination of APC in human serum samples. The results revealed that this strategy can be used to measure other proteins in biological samples.
  • An impedimetric molecularly-imprinted biosensor for Interleukin-1β
           determination, prepared by in-situ electropolymerization on carbon
           screen-printed electrodes
    • Abstract: Publication date: Available online 24 April 2019Source: BioelectrochemistryAuthor(s): Ana R. Cardoso, M.H. de Sá, M. Goreti F. SalesAbstractThis work reports the first electrochemical molecularly imprinted polymer (MIP) sensor for Interleukin-1beta (IL-1β) detection, based on modified commercial screen-printed carbon electrode (SPCE) was successfully demonstrated. For this purpose, the carbon support was modified with a PEDOT/4-aminothiophenol layer prior to the MIP film to enhance sensitivity and signal stability. The MIP layer was constructed on top of this by electropolymerization of Eriochrome black T (EBT) in the presence of IL-1β. The several steps of the biosensor assembly was followed by Raman spectroscopy and electroanalytical techniques.Using electrochemical impedance spectroscopy (EIS), a linear response in the range of 60 pM to 600 nM, with a LOD of 1.5 pM with (S/N = 3) was obtained in neutral PBS. Selectivity tests of the MIP biosensor made in spiked synthetic serum samples as well as against other structurally related (Myoglobin, of similar shape and size) or competing compounds (Immunoglobulin G, also present in the human serum) confirmed the good selectivity of the biosensor.Overall, the biosensor described herein has the potential to provide a simple and quick way for on-site screening of IL-1β, with low sample/reagent consumption and enabling direct serum analysis, which constitutes a valuable alternative to other conventional methods.
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