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  • Functionalized carbon nanotube adsorption interfaces for electron transfer studies of galactose oxidase
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-10-19
    Mulugeta B. Wayu, Michael J. Pannell, Najwa Labban, William S. Case, Julie A. Pollock, Michael C. Leopold
  • Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-10-16
    Laura Rago, Sarah Zecchin, Federica Villa, Andrea Goglio, Anna Corsini, Lucia Cavalca, Andrea Schievano

    A new approach to microbial electrosynthesis is proposed, aimed at producing whole biomass from N2 and inorganic carbon, by electrostimulation of complex microbial communities. On a carbon-based conductor under constant polarization (−0.7 V vs SHE), an electroactive biofilm was enriched with autotrophic nitrogen fixing microorganims and led to biomass synthesis at higher amounts (up to 18 fold), as compared to controls kept at open circuit (OC). After 110 days, the electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated with autotrophs (both Archaea and Bacteria) only in polarized biofilms, but not in OC. With this first proof of concept experiment, we propose to call this promising field ‘bioelectrochemical nitrogen fixation’ (e-BNF): a possible way to ‘power’ biological nitrogen fixation, organic carbon storage and soil fertility against desertification, and possibly a new tool to study the development of early prokaryotic life in extreme environments.

  • 更新日期:2018-10-11
  • Label-free independent quantitation of viable and non-viable cells using a multivariable multi-resonant sensor
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-10-10
    Radislav A. Potyrailo, Jon Dieringer, Victoria Cotero, Yongjae Lee, Steve Go, Matthew Schulmerich, Gunnar Malmquist, Andreas Castan, Klaus Gebauer, Vincent Pizzi

    Biological cells are utilized for diverse biotechnological and bioengineering purposes ranging from the production of biopharmaceuticals, to cell therapy, “human-on-a-chip” drug and toxicology assays, and drug-resistance tests. In these and other applications, it is critical to quantify the levels of not only viable but also non-viable cells. While traditional off-line cell-staining methods are available for counting of non-viable cells, many applications cannot periodically remove cells for their off-line analysis because of the risk of contamination or workflow logistics. Here we show in-situ label-free quantitation of viable and non-viable cells with multivariable multi-resonant sensors. We used Chinese hamster ovary (CHO) cells in suspension culture in single-use bioreactors as a representative example. The resonant sensor design strategy permitted enhanced sensor sensitivity versus conventional non-resonant measurements and probed the spectral dispersion of viable and non-viable cells with multiple resonances. These capabilities of label-free in-situ analysis of cell viability can be attractive in diverse cell applications such as cell suspensions, adhered cells, and their 3D assemblages.

  • Molecular and histological study on the effects of electrolytic electroporation on the liver
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-09-30
    Yanpeng Lv, Yanfang Zhang, Boris Rubinsky

    This study examined the temporal physiological and molecular events following the treatment of the liver with a tissue ablation modality that combined electroporation with electrolysis (E2). Rat liver was treated with an E2 waveform and the tissue examined, 1 h, 3 h, 6 h and 24 h with: H&E, Masson Trichrome, TUNEL stains and Western blot. H&E and TUNEL stains have shown that cell death began to be evident 3 h and hepatocyte regeneration was seen 24 h after treatment. H&E and Masson trichrome have shown that the extracellular matrix and the large lumens, appeared intact after E2. Western blot has shown the following molecular events after E2: cleaved caspase 3–downgraded at 1 h, upgraded at 24 h (apoptosis); cleaved Caspase 1 and cleaved GSDMD–upgraded at 6 h (pyroptosis), RIP3–upgraded at 1 h, MLKL–upgraded at 3 h (necroptosis). The mechanism of cell death was possible initiated by necroptosis pathway. Pyroptosis pathway was also activated. The observation that cell death from E2 was by programed necrosis and the details on the temporal molecular pathways, may have value for the recent attempt to combine electroporation mediated ablation with immunological treatment, by demonstrating that the cell death from E2 involves an inflammatory response and by providing data that could be used to design the optimal timing for the injection of immunological adjuvants.

  • The efficiency of heart protection with HTK or HTK-N depending on the type of ischemia
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-09-20
    Michael Schaefer, Martha-Maria Gebhard, Wolfgang Gross

    We investigated isolated guinea pig hearts (n = 121) in an ischemia/ reperfusion model with the aim to compare the efficiency of the cardioplegic solution HTK with its novel replacement HTKN.Following consolidation with Tyrode's solution, ischemia started either immediately or after preceding cardioplegia with HTK, HTKN, or modified HTK enriched with Ca. Ischemia lasted either 80 min at 30 °C, or 360 min at 5 °C, or 81 min at 30 °C with intermittent cardioplegic perfusion. During ischemia we measured intracellular calcium (iCa++) and the time of gap junction uncoupling (t-in). During reperfusion we measured the reestablishment of cell coupling (t-ret), left ventricular developed pressure (LVDP), and heart rhythm (VC-RR).In 5 °C groups, iCa++ at t-in was significantly higher than before ischemia, and longest t-in, shortest t-ret, and best VC-RR were observed after HTK-protection. Of all 30 °C groups, the intermittent group with modified HTK showed shortest t-ret, best VC-RR, and the highest LVDP. At 5 °C, HTK groups had higher LVDP than HTK-N groups, but not at 30 °C.The data suggest that the higher calcium level in the HTK-N solution improves reperfusion after short ischemia at 30 °C but for long lasting ischemia at 5 °C it is beneficial to use the HTK solution.

  • Effect of external resistance on the sensitivity of microbial fuel cell biosensor for detection of different types of pollutants
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-09-17
    Yue Yi, Beizhen Xie, Ting Zhao, Zhaoming Li, Devard Stom, Hong Liu
  • Low-cost nanowired α-MnO2/C as an ORR catalyst in air-cathode microbial fuel cell
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-09-15
    Mir Reza Majidi, Fatemeh Shahbazi Farahani, Mirghasem Hosseini, Iraj Ahadzadeh

    In this work, low cost α-MnO2 nanowires and α-MnO2 nanowires supported on carbon Vulcan (α-MnO2/C) have been synthesized via a simple and facile hydrothermal method for application in microbial fuel cells. The prepared samples have been characterized by X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FE-SEM). Electrocatalytic activities of the samples have been evaluated by means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a neutral phosphate buffer solution. EIS was performed at different potentials to gain further insight into the kinetic properties of α-MnO2/C. Both catalysts were used in air cathode microbial fuel cells to achieve power densities of 180 and 111 mWm−2 for α-MnO2/C and pristine α-MnO2 nanowires, respectively. α-MnO2/C functions as a good and economical alternative for Pt free catalysts in practical MFC applications, as shown by the findings of stability test and voltage generation cycles in long-term operation of MFC.

  • A novel bioelectrochemical method for real-time nitrate monitoring
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-09-15
    Shi-gang Su, Hao-yi Cheng, Ting-ting Zhu, Hong-cheng Wang, Ai-jie Wang

    Nitrate is one of the most common pollutants in the water environment. A key factor for the effective control and removal of nitrate is the ability to accurately determine the nitrate concentration in groundwater and the secondary effluent of wastewater treatment plants. Here, a bioelectrochemical method for real-time detection of the nitrate was developed. In this work, a kinetic model was developed to describe the correlation between the nitrate concentration and the current. Standard addition experiments showed the relative error between indicator predictions and ion chromatographic values ranged from 3.14% to 9.74%. The monitoring results of secondary effluent showed that the system could give a good response at different nitrate concentrations. The average error of not >10.85% between the indicator predictions and ion chromatographic values was demonstrated. This study offers a new method for the development of sustainable bioelectrochemical system (BES)-based technology for the real-time detection of nitrate in groundwater and the secondary effluent.

  • 更新日期:2018-09-07
  • Cell-seeded 3D scaffolds as in vitro models for electroporation
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-30
    Paola Brun, Monica Dettin, Luca Giovanni Campana, Fabrizio Dughiero, Paolo Sgarbossa, Clara Bernardello, Anna Lisa Tosi, Annj Zamuner, Elisabetta Sieni

    Electroporation of cells is usually studied using cell suspensions or monolayer cultures. 3D scaffolds for cell culture have been recently designed in order to reproduce in vitro the complex and multifactorial environment experimented in vivo by cells. In fact, it is well known that 2D cell cultures are not able to simulate the complex interactions between the cells and their extracellular matrix (ECM). Recently, some examples of 3D models, like spheroids, have been investigated also in the electroporation field. Spheroids have been proposed in electrochemotherapy (ECT) studies to mimic tumor in vivo conditions: they are easy-to-handle 3D models but their sensitivity to electric field pulses depends from their diameter and, more interestingly, despite being relevant for intercellular junctions, they are not so much so for cell-ECM interactions.In this work, we propose a 3D macroscopic myxoid matrix for cell culture that would mimic the in vivo environment of myxoid stroma tumors. The myxoid stroma consists of abundant basic substances with large amounts of glycosaminoglycans (hyaluronic acid) and proteoglycans, poor collagen fibers and no elastin content. In the proposed approach, tumor cells seeded on 3D scaffolds mimic of myxoid stroma can establish both cell-cell and cell-ECM 3D interactions.The MCF7 cells (human breast adenocarcinoma cell line) were seeded in complete culture medium. Cell cultures were incubated at 37 °C for either 24 h, 3 days or 7 day. Some samples were used to assess cell vitality using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) test and others for electroporation tests and for histopathological analysis. The electroporation has been verified by the fluorescent dye Propidium cellular uptake.The proposed myxoid stroma scaffold induces cell proliferation and shows fibrous structures produced by cells, the concentration of which increases with culture time. The proposed matrix will be used for further investigations as a new scaffold for cell culture. Tumor cells grown into these new scaffolds will be used to evaluate electroporation including the stroma effect.

  • Effect of isoelectric point on cheese whey wastewater treatment using a microbial electrochemical system
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-28
    Batoul Mohebrad, Abbas Rezaee, Beheshteh Sohrabi

    In 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.

  • 更新日期:2018-08-23
  • Electroanalytical characterization of the direct Marinobacter hydrocarbonoclasticus nitric oxide reductase-catalysed nitric oxide and dioxygen reduction
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-21
    Filipa O. Gomes, Luísa B. Maia, Cristina Cordas, Isabel Moura, Cristina Delerue-Matos, José J.G. Moura, Simone Morais

    Understanding the direct electron transfer processes between redox proteins and electrode surface is fundamental to understand the proteins mechanistic properties and for development of novel biosensors. In this study, nitric oxide reductase (NOR) extracted from Marinobacter hydrocarbonoclasticus bacteria was adsorbed onto a pyrolytic graphite electrode (PGE) to develop an unmediated enzymatic biosensor (PGE/NOR)) for characterization of NOR direct electrochemical behaviour and NOR electroanalytical features towards NO and O2. Square-wave voltammetry showed the reduction potential of all the four NOR redox centers: 0.095 ± 0.002, −0.108 ± 0.008, −0.328 ± 0.001 and −0.635 ± 0.004 V vs. SCE for heme c, heme b, heme b3 and non-heme FeB, respectively. The determined sensitivity (−4.00 × 10−8 ± 1.84 × 10−9 A/μM and - 2.71 × 10−8 ± 1.44 × 10−9 A/μM for NO and O2, respectively), limit of detection (0.5 μM for NO and 1.0 μM for O2) and the Michaelis Menten constant (2.1 and 7.0 μM for NO and O2, respectively) corroborated the higher affinity of NOR for its natural substrate (NO). No significant interference on sensitivity towards NO was perceived in the presence of O2, while the O2 reduction was markedly and negatively impacted (3.6 times lower sensitivity) by the presence of NO. These results clearly demonstrate the high potential of NOR for the design of innovative NO biosensors.

  • Metabolic shift of Klebsiella pneumoniae L17 by electrode-based electron transfer using glycerol in a microbial fuel cell
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-13
    Mi Yeon Kim, Changman Kim, Satish Kumar Ainala, Hyokwan Bae, Byong-Hun Jeon, Sunghoon Park, Jung Rae Kim
  • Electrical signal propagation within and between tomato plants
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-07
    Alexander G. Volkov, Yuri B. Shtessel
  • The contribution of lipid peroxidation to membrane permeability in electropermeabilization: A molecular dynamics study
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-04
    Lea Rems, Marilyne Viano, Marina A. Kasimova, Damijan Miklavčič, Mounir Tarek

    Electroporation or electropermeabilization is a technique that enables transient increase in the cell membrane permeability by exposing cells to pulsed electric field. However, the molecular mechanisms of the long-lived cell membrane permeability, which persists on the minutes time scale after the pulse treatment, remain elusive. Experimental studies have suggested that lipid peroxidation could present a mechanism of this prolonged membrane permeabilization. In this study we make the first important step in quantifying the possible contribution of lipid peroxidation to electropermeabilization. We use free energy calculations to quantify the permeability and conductance of bilayers, containing an increasing percentage of hydroperoxide lipid derivatives, to sodium and chloride ions. We then compare our calculations to experimental measurements on electropermeabilized cells. Our results show that the permeability and conductance increase dramatically by several orders of magnitude in peroxidized bilayers. Yet this increase is not sufficient to reasonably account for the entire range of experimental measurements. Nevertheless, lipid peroxidation might be considered an important mechanism of prolonged membrane permeabilization, if exposure of cells to high voltage electric pulses leads to secondary lipid peroxidation products. Our analysis calls for experimental studies, which will determine the type and amount of lipid peroxidation products in electropermeabilized cell membranes.

  • 更新日期:2018-07-30
  • Influence of cytochrome charge and potential on the cathodic current of electroactive artificial biofilms
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-22
    Stéphane Pinck, Mengjie Xu, Romain Clement, Elisabeth Lojou, Frédéric Jorand, Mathieu Etienne

    An electroactive artificial biofilm has been optimized for the cathodic reduction of fumarate by Shewanella oneidensis. The system is based on the self-assembly of multi-walled carbon nanotubes with bacterial cells in the presence of a c-type cytochrome. The aggregates are then deposited on an electrode to form the electroactive artificial biofilm. Six c-type cytochromes have been studied, from bovine heart or Desulfuromonas and Desulfuvibrio strains. The isoelectric point of the cytochrome controls the self-assembly process that occurs only with positively-charged cytochromes. The redox potential of the cytochrome is critical for electron transfer reactions with membrane cytochromes of the Mtr pathway. Optimal results have been obtained with c3 from Desulfovibrio vulgaris Hildenborough having an isoelectric point of 10.2 and redox potentials of the four hemes ranging between −290 and −375 mV vs. SHE. A current density of 170 μA cm−2 could be achieved in the presence of 50 mM fumarate. The stability of the electrochemical response was evaluated, showing a regular decrease of the current within 13 h, possibly due to the inactivation or leaching of loosely-bound cytochromes from the biofilm.

  • Direct electron transfer of lytic polysaccharide monooxygenases (LPMOs) and determination of their formal potentials by large amplitude Fourier transform alternating current cyclic voltammetry
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-20
    D. Zouraris, M. Dimarogona, A. Karnaouri, E. Topakas, A. Karantonis

    MtLPMO9 and FoLPMO9 are two lytic polysaccharide monooxygenases (LPMOs), from the filamentous fungi Thermothelomyces thermophila and Fusarium oxysporum, respectively. In the present study an attempt has been made to achieve direct electron transfer between these enzymes and a glassy carbon electrode by immobilization in Nafion polyelectrolyte. The method used to ascertain the feasibility of direct electron transfer was large amplitude Fourier transform alternating current voltammetry (FTacV) and the formal potentials of these enzymes were determined at different temperatures. The findings of this paper indicate that LPMOs can be studied by direct electron transfer, which could be exploited in the near future for their biochemical characterization.

  • The effect of quercetin on the electrical properties of model lipid membranes and human glioblastoma cells
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-20
    Marcin Kruszewski, Magdalena Kusaczuk, Joanna Kotyńska, Miroslav Gál, Rafał Krętowski, Marzanna Cechowska-Pasko, Monika Naumowicz

    Quercetin is a naturally-occurring flavonoid claimed to exert many beneficial health effects. In this report, the influence of quercetin on the surface charge of phosphatidylcholine liposomes and human glioblastoma LN-229 and LN-18 cells was studied using microelectrophoretic mobility measurements. The effect of quercetin on the electrical resistance and capacitance of bilayer lipid membranes was analyzed via electrochemical impedance spectroscopy. The results showed that after flavonoid treatment, the cell lines demonstrated changes in surface charge only in alkaline pH solutions, whereas there were no significant alterations in quercetin-treated vs. control cells in acidic pH solutions. The same tendency was found for liposomal membranes proving that quercetin insertion into membranes is strongly pH-dependent. Capacitance and resistance measurements conducted in acidic electrolyte solutions demonstrated an increase in both electrical parameters, indicating an increased amount of quercetin inserted into the bilayers. Moreover, the cytotoxic effect of quercetin confirms that the flavonoid enters the cells and perturbs the proliferation of LN-229 and LN-18 glioblastoma cell lines. As such, our results indicate that the specific localization of quercetin, membrane-bound or cell-entering, might be crucial for its pharmacological activity. However, further studies are necessary prior to applying these physicochemical measurements as standard methods of evaluating drug activity.

  • Protein crosslinking improves the thermal resistance of plastocyanin immobilized on a modified gold electrode
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-20
    José Luis Olloqui-Sariego, Antonio Díaz-Quintana, Miguel Ángel De la Rosa, Juan José Calvente, Inmaculada Márquez, Irene Díaz-Moreno, Rafael Andreu

    Increasing the thermal stability of immobilized proteins is a motivating goal for improving the performance of electrochemical biodevices. In this work, we propose the immobilization of crosslinked plastocyanin from the thermophilic cyanobacterium Phormidium laminosum by simultaneous incubation of a mixture of plastocyanin and the coupling reagents. The thermal stability of the so built covalently immobilized protein films has been assessed by cyclic voltammetry in the 0–90 °C temperature range and has been compared to that of physisorbed films. It is shown that the protein loss along a thermal cycle is significantly reduced in the case of the crosslinked films, whose redox properties remain unaltered along a cyclic heating-cooling thermal scan, and can withstand the contact with 70 °C solutions for four hours. Comparison of thermal unfolding curves obtained by circular dichroism spectroscopy of both free and crosslinked protein confirms the improved thermic resistance of the crosslinked plastocyanin. Notably, the electron transfer thermodynamics of physisorbed and crosslinked plastocyanin films are quite similar, suggesting that the formation of intra- and inter-protein amide bonds do not affect the integrity and functionality of the copper redox centers. UV–Vis absorption and circular dichroism measurements corroborate that protein crosslinking does not alter the coordination geometry of the metal center.

  • Double strand DNA-based determination of menadione using a Fe3O4 nanoparticle decorated reduced graphene oxide modified carbon paste electrode
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-19
    Maryam Hosseini Ghalehno, Mohammad Mirzaei, Masoud Torkzadeh-Mahani

    In this work an electrochemical label free DNA biosensor (ds-DNA) for the determination of menadione (MD) was developed. The biosensor was constructed using a modified nanocomposite consisting of Fe3O4 nanoparticles decorated reduced graphene oxide (Gr) on a carbon paste electrode (CPE). Scanning electron microscope (SEM), energy dispersive X-ray (EDAX) and Fourier transform infrared (FT-IR) spectroscopy confirmed the structure of the synthesized nanocomposites (electrode composition). The Gr-Fe3O4 nanocomposites formed a sensitive layer with large surface area. Electrochemical studies revealed that modification of the electrode surface with ds-DNA and Gr- Fe3O4 nanocomposite significantly increases the oxidation peak currents and reduces the peak potentials of MD. Under the optimum conditions, calibration curve was linear in the range of 0.3–100.0 nM with a detection limit of 0.13 nM. The relative standard deviation for 50.0 nM was 3.90% (n = 5). The proposed biosensor was successfully applied to the determination of MD.

  • Enhancing extracellular electron transfer efficiency and bioelectricity production by vapor polymerization Poly (3,4-ethylenedioxythiophene)/MnO2 hybrid anode
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-17
    Panpan Liu, Changyong Zhang, Peng Liang, Yong Jiang, Xiaoyuan Zhang, Xia Huang

    Electron transfer efficiency in electroactive biofilm is the limiting factor for bioelectricity output of bioelectrochemical system. Here, carbon felt (CF) is coated with manganese dioxide (MnO2) which acts as electron mediator in electroactive biofilm. A wrapping layer of conducting Poly 3,4-ethylenedioxythiophene is developed to protect the MnO2 and enhance electron transfer efficiency of MnO2 mediator. The hybrid bioanode (PEDOT/MnO2/CF bioanode) delivered the highest electron transfer efficiency (6.3 × 10−9 mol cm−2 s−1/2) and the highest capacitance of 4.78 F, much higher than bare CF bioanode (1.50 ± 0.04 × 10−9 mol cm−2 s−1/2 and 0.42 F). As a result, microbial fuel cells could produce a maximum power density of 1534 ± 13 mW m−2, approximately 57.7% higher than that with the bare carbon felt anode (972 ± 21 mW m−2). Possible mechanisms are proposed to help understanding the different function of the PEDOT and MnO2 on the anodic layer. This study introduces an effective method for the fabrication of high performance anode.

  • Cell membrane electroporation modeling: A multiphysics approach
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-03
    Ezequiel Goldberg, Cecilia Suárez, Mauricio Alfonso, Juan Marchese, Alejandro Soba, Guillermo Marshall

    Electroporation-based techniques, i.e. techniques based on the perturbation of the cell membrane through the application of electric pulses, are widely used at present in medicine and biotechnology. However, the electric pulse - cell membrane interaction is not yet completely understood neither explicitly formalized. Here we introduce a Multiphysics (MP) model describing electric pulse - cell membrane interaction consisting on the Poisson equation for the electric field, the Nernst-Planck equations for ion transport (protons, hydroxides, sodium or calcium, and chloride), the Maxwell tensor and mechanical equilibrium equation for membrane deformations (with an explicit discretization of the cell membrane), and the Smoluchowski equation for membrane permeabilization. The MP model predicts that during the application of an electric pulse to a spherical cell an elastic deformation of its membrane takes place affecting the induced transmembrane potential, the pore creation dynamics and the ionic transport. Moreover, the coincidence among maximum membrane deformation, maximum pore aperture, and maximum ion uptake is predicted. Such behavior has been corroborated experimentally by previously published results in red blood and CHO cells as well as in supramolecular lipid vesicles.

  • Effects of solidification cooling rate on the corrosion resistance of a biodegradable β-TCP/Mg-Zn-Ca composite
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-07
    Qiang Yuan, Y. Huang, Debao Liu, Minfang Chen

    Biodegradable beta-tricalcium phosphate (β-TCP) particle reinforced magnesium metal matrix composites (Mg-MMC) have attracted increasing interest for application as implant materials. This investigation was conducted to study the effect of cooling rate on the microstructure and corrosion behavior of a biodegradable β-TCP/Mg-Zn-Ca composite. The composite was fabricated under a series of cooling rates using a wedge-shaped casting mold. The microstructure of the composite was examined by optical and scanning electron microscopy, and the corrosion behavior was investigated using an electrochemical workstation and immersion tests in a simulated body fluid (SBF). Faster cooling rates were shown to refine the secondary phase and grain size, and produce a more homogenous microstructure. The refined microstructure resulted in a more uniform distribution of β-TCP particles, which is believed to be beneficial in the formation of a stable and compact corrosion product layer, leading to improved corrosion resistance for the composite.

  • Single cell dielectrophoresis study of apoptosis progression induced by controlled starvation
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-05
    Elham Salimi, Katrin Braasch, Azita Fazelkhah, Samaneh Afshar, Bahareh Saboktakin Rizi, Kaveh Mohammad, Michael Butler, Greg E. Bridges, Douglas J. Thomson

    Nutrient depletion in fed-batch cultures and at the end of batch cultures is among the main causes of stress on cells and a trigger of apoptosis. In this study, we investigated changes in the cytoplasm conductivity of Chinese hamster ovary (CHO) cells under controlled starvation. Employing a single-cell dielectrophoresis (DEP) cytometer, we measured the DEP response of CHO cells incubated in a medium without glucose and glutamine over a 48-h period. Using the measured data in conjunction with numerical simulations, we determined the cytoplasm conductivity of viable and apoptotic cell subpopulations. The results show that a small subpopulation of apoptotic cells emerges after 24 to 36 h of starvation and increases rapidly over a short period of time, <12 h. The apoptotic cells have a dramatically lower cytoplasm conductivity, ∼0.05 S/m, than viable cells, ∼0.45 S/m. Viability of starvation cultures was measured by fluorescent cytometry, DEP cytometry, and trypan blue exclusion assays. DEP, Annexin V, caspase-8, and 7-AAD assays show a similar decline in viability after 36 h of starvation and indicate a very low viability after 48 h. Trypan blue exclusion assay fails to detect early-stage viability decline and estimates a much higher viability after 48 h.

  • A novel approach for the selective analysis of l-lysine in untreated human serum by a co-crosslinked l-lysine–α-oxidase/overoxidized polypyrrole bilayer based amperometric biosensor
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-06
    Rosanna Ciriello, Francesca De Gennaro, Silvio Frascaro, Antonio Guerrieri

    An amperometric biosensor based on an l-lysine-α-oxidase (LO) layer immobilized by co-crosslinking onto the surface of an overoxidized polypyrrole modified Pt electrode (Pt/oPPy) and able to analyse l-lysine (Lys) in untreated human serum is described. The sensing electrode has been characterised and a proper enzyme kinetics optimisation permits to use a low specific enzyme as LO from Trichoderma viride for the selective biorecognition of Lys in the presence of other interferent amino acids; a kinetics study of LO evidenced also the allosteric behaviour of this enzyme, a kinetic feature which was never reported before for this enzyme. The biosensor showed a sensitivity of 0.11 μA/mM mm2, linear responses up to 4 mM and a limit of detection of 2 μM; the within-a-day coefficients of variation for replicate (n = 5) were 0.92% and 1.35% at 4 mM and 0.2 mM Lys levels, respectively. The permselective behaviour of Pt/oPPy modified electrode assured an interference- and fouling-free determination of Lys even in untreated serum samples. The determination of Lys in human serum from healthy donors gave Lys levels in good agreement with the expected values so that the use of the proposed biosensor appears promising in the relevant clinical fields.

  • Conductometric biosensor for arginine determination in pharmaceutics
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-05
    O.V. Soldatkina, O.O. Soldatkin, T.P. Velychko, V.O. Prilipko, M.A. Kuibida, S.V. Dzyadevych

    A new conductometric biosensor based on coimmobilized urease and arginase has been developed for arginine determination in pharmaceutics. First, the main parameters of the selected method of immobilization (concentrations of arginase, urease, and glutaraldehyde, time of incubation) were optimized. An influence of the solution parameters (buffer ionic strength, capacity, pH, Mn2+ concentration) on the biosensor operation was studied, working conditions were optimized. After biosensor optimization, the main analytical characteristics were as follows. The limit of detection - 2.5 μM, the linear range - 2.5–500 μM, the sensitivity to arginine 13.4 ± 2.4 μS/mM, the response time - 20 s. The signals repeatability and operational stability in continuous exploitation were studied over one working day and during one week. Additionally, the selectivity of the developed biosensor towards arginine was essayed relative to other amino acids. The developed biosensor has been used to measure arginine concentrations in some drugs. The results obtained were in high correlation with the characteristics declared by producers.

  • Evaluating the efficiency of a photoelectrochemical electrode constructed with photosystem II-enriched thylakoid membrane fragments
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-23
    Yang Liu, John Daye, David Jenson, Stephen Fong

    The photoelectrochemical electrode has been intensively studied in recent years as a means of generating electricity from light through the use of intact thylakoid membranes or highly purified photosystem II. PSII-enriched thylakoid membrane fragments (PSII-BBY), also have the potential to construct the photoelectrochemical anode. In this study, we examined the feasibility of utilizing PSII-BBY preparations to construct a relatively inexpensive photoelectrochemical anode with a comparable current density and a reasonable stability. Intact thylakoid membrane based photoelectrochemical electrode was also constructed to compare with the PSII-BBY based photoelectrochemical electrode with respect to the protein activity and current density. In addition, the practicability of replacing the popular gold nanoparticle modified gold slide with multi-walled carbon nanotube modified indium tin oxide coated slides was tested. In order to understand the surface change during slide surface modification, an atomic force microscope (AFM) was used to image the topography of the slide. Above all, we observed a current density of 20.44 ± 1.58 μA/cm2 when PSII-BBY was used to construct the photoelectrochemical anode. Moreover, the PSII-BBY based photoelectrochemical anode showed high stability over time with the current decreasing at a rate of 0.78%/h.

  • 更新日期:2018-07-12
  • Electrode plate-culture methods for colony isolation of exoelectrogens from anode microbiomes
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-22
    N. Ueoka, A. Kouzuma, K. Watanabe

    Exoelectrogens play central roles in microbial fuel cells and other bioelectrochemical systems (BESs), yet their physiological diversity remains largely elusive due to the lack of efficient methods for the isolation from naturally occurring microbiomes. The present study developed an electrode plate-culture (EPC) method that facilitates selective colony formation by exoelectrogens and used it for isolating them from an exoelectrogenic microbiome enriched from paddy-field soil. In an EPC device, the surface of solidified agarose medium was spread with a suspension of a microbiome and covered with a transparent fluorine doped tin oxide (FTO) electrode (poised at 0 V vs. the standard hydrogen electrode) that served as the sole electron acceptor. The medium contained acetate as the major growth substrate and Coomassie Brilliant Blue as a dye for visualizing colonies under FTO. It was shown that colonies successfully appeared under FTO in association with current generation. Analyses of 16S rRNA gene sequences of colonies indicated that they were affiliated with genera Citrobacter, Geobacter and others. Among them, Citrobacter and Geobacter isolates were found to be exoelectrogenic in pure-culture BESs. These results demonstrate the utility of the EPC method for colony isolation of exoelectrogens.

  • Challenges for successful implantation of biofuel cells
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-18
    Abdelkader Zebda, Jean-Pierre Alcaraz, Pankaj Vadgama, Sergey Shleev, Shelley D. Minteer, François Boucher, Philippe Cinquin, Donald K. Martin

    There is a growing interest in the design and engineering of operational biofuel cells that can be implanted. This review highlights the recent progress in the electrochemistry of biofuel cell technologies, but with a particular emphasis on the medical and physiological aspects that impact the biocompatibility of biofuel cells operating inside a living body. We discuss the challenge of supplying power to implantable medical devices, with regard to the limitations of lithium battery technology and why implantable biofuel cells can be a promising alternative to provide the levels of power required for medical devices. In addition to the challenge of designing a biofuel cell that provides a stable level of sufficient power, the review highlights the biocompatibility and biofouling problems of implanting a biofuel cell that have a major impact on the availability of the substrates inside body that provide fuel for the biofuel cell. These physiological challenges and associated ethical considerations are essential to consider for biofuel cells that are designed to be implanted for long-term operation inside a living animal and eventually to human clinical applications.

  • Nanosecond pulsed electric field induces calcium mobilization in osteoblasts
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-23
    Ping Zhou, Fei He, Yu Han, Bin Liu, Shicheng Wei

    Nanosecond pulsed electric field (nsPEF) has the ability to induce a host of intracellular biochemical processes in living cells as a function of parameter setting. In vitro experiments proved that nsPEF stimulation could remarkably promote biomineralization processes and new bone formation. However, the impact of nsPEF parameter settings on the calcium flux of osteoblasts, as well as the intracellular mechanisms underlying those observations have yet to be elucidated. In this study, live osteoblast-like MG63 cells were loaded with fluorescence indicator dye fluo-4 AM. nsPEF stimulation could induce intracellular calcium mobilization in MG63 cells with no refractory period. We confirmed that moderate output voltage (4–8 KV) and large pulse number (25) were required for efficient nsPEF irritation of MG63 cells. Additionally, nsPEF stimulation-induced calcium flux in MG63 cells was dramatically reduced with the treatment by ethylene glycol tetraacetic acid (EGTA), proving that the intake of extracellular calcium ions is crucial for increasing intracellular calcium concentration of nsPEF-treated MG63 cells. Our preliminary study investigated the mechanisms underlying nsPEF stimulation-induced calcium mobilization in osteoblast-like cells, and it has the potential to accelerate the application of nsPEF stimulation in new bone formation.

  • Mechanisms of antimelanoma effect of oat β-glucan supported by electroporation
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-06
    Anna Choromanska, Sandra Lubinska, Anna Szewczyk, Jolanta Saczko, Julita Kulbacka
  • Electrochemotherapy with cisplatin or bleomycin in head and neck squamous cell carcinoma: Improved effectiveness of cisplatin in HPV-positive tumors
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-06
    Ajda Prevc, Martina Niksic Zakelj, Simona Kranjc, Maja Cemazar, Janez Scancar, Tina Kosjek, Primoz Strojan, Gregor Sersa

    Human papillomavirus (HPV) is an important etiological factor in head and neck squamous cell carcinomas (SCCs). Standard treatment of HPV-positive tumors with platinum-based radio(chemo)therapy results in a better outcome than in HPV-negative tumors. Electrochemotherapy is becoming an increasingly recognized mode of treatment in different cancers; thus, its use in the management of head and neck SCC is of considerable interest. However, response to electrochemotherapy according to HPV status of the tumors has not been evaluated yet. Thus, our aim was to compare the effect of electrochemotherapy with cisplatin or bleomycin between HPV-negative and HPV-positive human pharyngeal SCC derived cell lines and tumor models. HPV-positive cells and tumors were found to be more sensitive to electrochemotherapy with cisplatin than HPV-negative ones, whereas sensitivity to electrochemotherapy with bleomycin was similar irrespective of the HPV status. The higher sensitivity of HPV-positive cells and tumors to electrochemotherapy with cisplatin is likely due to the higher level and slower repair of DNA damage. In HPV-negative tumors, a higher number of complete responses was recorded after bleomycin-based rather than cisplatin-based electrochemotherapy, while in HPV-positive tumors electrochemotherapy with cisplatin was more effective.

  • 更新日期:2018-07-12
  • Nanosecond bipolar pulse generators for bioelectrics
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-26
    Shu Xiao, Chunrong Zhou, Enbo Yang, Sambasiva R. Rajulapati

    Biological effects caused by a nanosecond pulse, such as cell membrane permeabilization, peripheral nerve excitation and cell blebbing, can be reduced or cancelled by applying another pulse of reversed polarity. Depending on the degree of cancellation, the pulse interval of these two pulses can be as long as dozens of microseconds. The cancellation effect diminishes as the pulse duration increases. To study the cancellation effect and potentially utilize it in electrotherapy, nanosecond bipolar pulse generators must be made available. An overview of the generators is given in this paper. A pulse forming line (PFL) that is matched at one end and shorted at the other end allows a bipolar pulse to be produced, but no delay can be inserted between the phases. Another generator employs a combination of a resistor, an inductor and a capacitor to form an RLC resonant circuit so that a bipolar pulse with a decaying magnitude can be generated. A third generator is a converter, which converts an existing unipolar pulse to a bipolar pulse. This is done by inserting an inductor in a transmission line. The first phase of the bipolar pulse is provided by the unipolar pulse's rising phase. The second phase is formed during the fall time of the unipolar pulse, when the inductor, which was previously charged during the flat part of the unipolar pulse, discharges its current to the load. The fourth type of generator uses multiple MOSFET switches stacked to turn on a pre-charged, bipolar RC network. This approach is the most flexible in that it can generate multiphasic pulses that have different amplitudes, delays, and durations. However, it may not be suitable for producing short nanosecond pulses (<100 ns), whereas the PFL approach and the RLC approach with gas switches are used for this range. Thus, each generator has its own advantages and applicable range.

  • Electrodeposited styrylquinolinium dye as molecular electrocatalyst for coupled redox reactions
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-10
    Yolina Hubenova, Rumyana Bakalska, Mario Mitov
  • Engineered fungus derived FAD-dependent glucose dehydrogenase with acquired ability to utilize hexaammineruthenium(III) as an electron acceptor
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-10
    Madoka Okurita, Nanami Suzuki, Noya Loew, Hiromi Yoshida, Wakako Tsugawa, Kazushige Mori, Katsuhiro Kojima, David C. Klonoff, Koji Sode

    Fungal FAD-dependent glucose dehydrogenases (FADGDHs) are considered to be superior enzymes for glucose sensor strips because of their insensitivity to oxygen and maltose. One highly desirable mediator for enzyme sensor strips is hexaammineruthenium(III) chloride because of its low redox potential and high storage stability. However, in contrast to glucose oxidase (GOx), fungal FADGDH cannot utilize hexaammineruthenium(III) as electron acceptor. Based on strategic structure comparison between FADGDH and GOx, we constructed a mutant of Aspergillus flavus-derived FADGDH, capable of utilizing hexaammineruthenium(III) as electron acceptor: AfGDH-H403D. In AfGDH-H403D, a negative charge introduced at the pathway-entrance leading to the FAD attracts the positively charged hexaammineruthenium(III) and guides it into the pathway. The corresponding amino acid in wild-type GOx is negatively charged, which explains the ability of GOx to utilize hexaammineruthenium(III) as electron acceptor. Electrochemical measurements showed a response current of 46.0 μA for 10 mM glucose with AfGDH-H403D and hexaammineruthenium(III), similar to that with wild-type AfGDH and ferricyanide (47.8 μA). Therefore, AfGDH-H403D is suitable for constructing enzyme electrode strips with hexaammineruthenium(III) chloride as sole mediator. Utilization of this new, improved fungal FADGDH should lead to the development of sensor strips for blood glucose monitoring with increased accuracy and less stringent packing requirements.

  • Kinetic competition between microbial anode respiration and nitrate respiration in a bioelectrochemical system
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-02
    Shi-gang Su, Hao-yi Cheng, Ting-ting Zhu, Hong-cheng Wang, Ai-jie Wang

    The Nernst-Monod model is used to describe bio-anode performance with respect to the effect of the electron donor and anode potential. However, electron competition is not considered in the model, limiting its application in wastewater treatment systems. In this work, nitrate was employed to describe the influence of a competitive electron acceptor on bio-anode performance. A new dynamic model of microbial anode respiration and nitrate respiration was developed for the removal of nitrogen oxides. The competitive relationship between microbial anode respiration and nitrate respiration was investigated based on electron transfer as described by the kinetics of Nernst-Monod electron transfer and nitrate reduction. The experimental results showed that nitrate had a significant influence on microbial anode respiration. The model parameters were estimated with the experimental results obtained in a continuous-flow bioelectrochemical system (BES) fed with acetate. The simulated results revealed that nitrate respiration could indirectly affect the microbial anode respiration by altering the available substrate concentration. In addition, bacterial community analysis indicated that there were two dominant functional microorganisms coexisting in the anode chamber. The first microorganism was represented by Geobacter, which has extracellular electron-transfer abilities. The second was denitrifying bacteria, which can use the carbon sources in the anodic chamber and electrons from the electrode for nitrate reduction. This is the first time that mathematical modelling of nitrate reduction has been applied to BESs.

  • Enhancing extracellular electron transfer between Pseudomonas aeruginosa PAO1 and light driven semiconducting birnessite
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-02
    Guiping Ren, Yuan Sun, Yang Ding, Anhuai Lu, Yan Li, Changqiu Wang, Hongrui Ding
  • Electrochemical and spectroscopic studies of the interaction of antiviral drug Tenofovir with single and double stranded DNA
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-06-02
    Kamila Morawska, Tomasz Popławski, Witold Ciesielski, Sylwia Smarzewska
  • Microbial anodic consortia fed with fermentable substrates in microbial electrolysis cells: Significance of microbial structures
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-28
    Clément Flayac, Eric Trably, Nicolas Bernet

    Microbial community structure of anodic biofilms plays a key role in bioelectrochemical systems (BESs). When ecosystems are used as inocula, many bacterial species having interconnected ecological interactions are present. The aim of the present study was to identify these interactions for the conversion of single substrates into electrical current. Dual-chamber reactors were inoculated with activated sludge and fed in batch mode with acetate, lactate, butyrate and propionate at 80 mMe− equivalents in quadruplicate. Analyses of biofilms and planktonic microbial communities showed that the anodic biofilms were mainly dominated by the Geobacter genus (62.4% of the total sequences). At the species level, Geobacter sulfurreducens was dominant in presence of lactate and acetate, while Geobacter toluenoxydans and Geobacter pelophilus were dominant with butyrate and propionate as substrates. These results indicate for the first time a specificity within the Geobacter genus towards the electron donor, suggesting a competitive process for electrode colonization and the implementations of syntrophic interactions for complete oxidation of substrates such as propionate and butyrate. All together, these results provide a new insight into the ecological relationships within electroactive biofilms and suggest eco-engineering perspectives to improve the performances of BESs.

  • A sensitive electrochemiluminescent biosensor based on AuNP-functionalized ITO for a label-free immunoassay of C-peptide
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-23
    Xiang Liu, Chen Fang, Jilin Yan, Huiling Li, Yifeng Tu

    The C-peptide is a co-product of pancreatic β-cells during insulin secretion; its content in body fluid is closely related to diabetes. This paper reports an immune-sensing strategy for a simple and effective assay of C-peptide based on label-free electrochemiluminescent (ECL) signaling, with high sensitivity and specificity. The basal electrode was constructed of an indium tin oxide (ITO) glass as a conductive substrate, which was decorated by Au nanoparticles (AuNPs) with hydrolysed (3-aminopropyl)trimethoxysilane as the linker. The characteristics of the fabricated electrode were investigated by electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. After immobilizing the C-peptide antibody, which takes great advantage of AuNPs' binding capacity, this immunosensor can quantify C-peptide using luminol as the ECL probe. By measuring ECL inhibition, calibration can be established to report the C-peptide concentration between 0.05 ng mL−1 and 100 ng mL−1 with a detection limit of 0.0142 ng mL−1. As a proof of concept, the proposed strategy is a promising and versatile platform for the clinical diagnosis, classification, and research of diabetes.

  • Exfoliated molybdenum di-sulfide (MoS2) electrode for hydrogen production in microbial electrolysis cell
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-19
    Shmuel Rozenfeld, Hanan Teller, Michal Schechter, Ravit Farber, Olga Krichevski, Alex Schechter, Rivka Cahan

    The most widely reported catalyst in microbial electrochemical cells (MEC) cathodes is platinum (Pt). The disadvantages of Pt include its high cost and sensitivity to various molecules. In this research an exfoliated molybdenum di-sulfide (MoS2-EF) catalyst was synthesized. The size of the obtained particles was 200 ± 50 nm, 50-fold smaller than the pristine MoS2 catalyst. The MoS2-EF Raman spectrum displays the E12g and A1g peaks at 373 cm−1 and 399 cm−1. Electrochemical characterization by linear sweep voltammetry (LSV) of a rotating disc electrode RDE showed that the current density of Pt in 0.5 M H2SO4 was 3.3 times higher than MoS2-EF. However, in phosphate buffer (pH-7) electrolyte this ratio diminished to 1.9. The polarization curve of Pt, MoS2-EF and the pristine MoS2 electrodes, at −1.3 V in MEC configuration in abiotic conditions exhibit current densities of 17.46, 12.67 and 3.09 mA cm−2, respectively. Hydrogen evolution rates in the same MEC with a Geobacter sulfurreducens anode and Pt, MoS2-EF and the pristine MoS2 cathodes were 0.106, 0.133 and 0.083 m3 d−1 m−3, respectively. The results in this study show that MoS2-EF led to highly purified hydrogen and that this catalyst can serve as an electrochemical active and cost-effective alternative to Pt.

  • Interaction of DNA and mononucleotides with theophylline investigated using electrochemical biosensors and biosensing
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-03
    Katarína Nemčeková, Ján Labuda, Viktor Milata, Jana Blaškovičová, Jozef Sochr
  • Investigation of interactions of Comtan with human serum albumin by mathematically modeled voltammetric data: A study from bio-interaction to biosensing
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-10
    Ali R. Jalalvand, Sirous Ghobadi, Hector C. Goicoechea, Hui-Wen Gu, Esmael Sanchooli

    In this work, voltammetric data recorded at a glassy carbon electrode (GCE) were separately used to investigate the interactions of entacapone (Comtan, CAT) with human serum albumin (HSA). Then, an augmented data matrix was constructed by the combination of voltammetric and spectroscopic data and simultaneously analysed by multivariate curve resolution-alternating least squares (MCR-ALS) to obtain more information about CAT-HSA interactions. The absence of rotational ambiguities in results obtained by MCR-ALS was verified with the help of MCR-BANDS and we confirmed that the results were unambiguous and reliable. Binding of CAT to HSA was also modeled by molecular docking and the results were compatible with those of obtained by recording experimental data. Hard-modeling of combined voltammetric and spectroscopic data by EQUISPEC as an efficient chemometric algorithm helped us to compute binding constant of CAT-HSA complex specie which was in a good agreement with the binding constant value obtained by direct analysis of experimental data. For electrochemical sensing of serum albumin two amperometric measurements were performed to determine HSA in 2–27 nM and 27–70 nM with a limit of detection of 0.51 nM and a sensitivity of 1.84 μA nM−1.

  • Reactivation of standard [NiFe]-hydrogenase and bioelectrochemical catalysis of proton reduction and hydrogen oxidation in a mediated-electron-transfer system
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-05
    Saeko Shiraiwa, Keisei So, Yu Sugimoto, Yuki Kitazumi, Osamu Shirai, Koji Nishikawa, Yoshiki Higuchi, Kenji Kano
  • Electrotrophic activity and electrosynthetic acetate production by Desulfobacterium autotrophicum HRM2
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-04
    Zehra Zaybak, Bruce E. Logan, John M. Pisciotta

    Electroautotrophic microorganisms accept electrons from a cathode as source of reducing equivalents to drive CO2 fixation by poorly understood mechanisms. Acetogenic bacteria were the first group found to possess the capability for electroautotrophic metabolism in pure culture with associated electrosynthesis of acetate as primary metabolite. Identification of additional electrotrophic species can contribute to our understanding of this unusual form of metabolism. Here, bioelectrochemical techniques, chemical analysis and microscopy were used to determine electrotrophic metabolism of Desulfobacterium autotrophicum HRM2. Chronoamperometry showed increasing current uptake over 21 days of incubation in duplicate bioelectrochemical system sets. Linear sweep voltammetry indicated peak current uptake at −243 mV. High performance liquid chromatography (HPLC) analysis quantified acetate accumulation in anaerobic minimal media containing inorganic carbon as sole carbon source, consistent with electrosynthesis. Scanning electron microscopy and live/dead staining by epifluorescence microscopy analysis indicated viable 1–2 μm cells after 76 days of cultivation under electroautotrophic conditions. The genome of Db. autotrophicum HRM2 is fully sequenced and, thus, could provide insight into the biochemical and physiological mechanisms by which electrotrophic cells utilize cathode-derived electrons. This research expands the diversity of facultative autotrophs capable of electrotrophic metabolism to include the sulfate-reducing marine bacterium Db. autotrophicum HRM2.

  • Electricity generation and microbial communities in microbial fuel cell powered by macroalgal biomass
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-05
    Nannan Zhao, Yinan Jiang, Merlin Alvarado-Morales, Laura Treu, Irini Angelidaki, Yifeng Zhang
  • The anti-biofouling behavior of high voltage pulse electric field (HPEF) mediated by carbon fiber composite coating in seawater
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-25
    Tiantian Feng, Jinyi Wu, Ke Chai, Pengpeng Yang

    One of the most important research areas in the marine industry is to investigate new and effective anti-biofouling technologies. In this study, high voltage pulse electric field (HPEF) mediated by carbon fiber (CF) composite coating was utilized to prevent the fouling of bacteria, microalgae and barnacle larvae in seawater. The plate count, 2, 3, 5-triphenyl-tetrazolium chloride (TTC) reduction assay and neutral red (NR) staining and larval motility detection showed that the inactivation rates were at the highest levels, which reached 99.1%, 99.9%, 99.7%, 98.7% and 85% respectively for Pseudomonas sp., Vibrio sp., iron bacteria, Navicula sp. and the second stage nauplii of Balanus reticulatus, under the HPEF with 19 kV pulse amplitude, 23.15 kHz frequency and 0.5 duty cycle. The field-emission scanning electron microscopy (FE-SEM) of Navicula sp. revealed that the HPEF brought about the cell lysis and the cell organic matter release on the coating, which could be the mechanism of the inactivation by the HPEF. Additionally, the FE-SEM and Raman spectroscopy indicated that the HPEF hardly damaged the coating.

  • An electrochemical sensing approach for scouting microbial chemolithotrophic metabolisms
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-01
    Albert Saavedra, Federico Figueredo, Eduardo Cortón, Ximena C. Abrevaya
  • Binder materials for the cathodes applied to self-stratifying membraneless microbial fuel cell
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-19
    Xavier Alexis Walter, John Greenman, Ioannis Ieropoulos

    The recently developed self-stratifying membraneless microbial fuel cell (SSM-MFC) has been shown as a promising concept for urine treatment. The first prototypes employed cathodes made of activated carbon (AC) and polytetrafluoroethylene (PTFE) mixture. Here, we explored the possibility to substitute PTFE with either polyvinyl-alcohol (PVA) or PlastiDip (CPD; i.e. synthetic rubber) as binder for AC-based cathode in SSM-MFC. Sintered activated carbon (SAC) was also tested due to its ease of manufacturing and the fact that no stainless steel collector is needed. Results indicate that the SSM-MFC having PTFE cathodes were the most powerful measuring 1617 μW (11 W·m−3 or 101 mW·m−2). SSM-MFC with PVA and CPD as binders were producing on average the same level of power (1226 ± 90 μW), which was 24% less than the SSM-MFC having PTFE-based cathodes. When balancing the power by the cost and environmental impact, results clearly show that PVA was the best alternative. Power wise, the SAC cathodes were shown being the less performing (≈1070 μW). Nonetheless, the lower power of SAC was balanced by its inexpensiveness. Overall results indicate that (i) PTFE is yet the best binder to employ, and (ii) SAC and PVA-based cathodes are promising alternatives that would benefit from further improvements.

  • Electrochemical behavior of pyrite in sulfuric acid in presence of amino acids belonging to the amino acid sequence of rusticyanin
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-01
    Biljana S. Maluckov, Miodrag N. Mitrić

    The impact of different concentrations of three amino acids (cysteine, histidine and methionine) which are part of the amino acid sequence of rusticyanin on dissolution of pyrite is investigated by the application of electrochemical techniques. Cyclic voltammetric studies conducted in the anodic direction from corrosion potential have shown that in the vicinity of corrosion potential, histidine and methionine do not influence dissolution of pyrite independently on their concentrations. On the other hand, cysteine and solutions of these amino acids in the molar ratios Cys:His:Met/1:1:1 and Cys:His:Met/1:2:1 accelerate dissolution at concentrations 10−2 mol L−1 and 10−3 mol L−1. Potentiodynamic polarization measurements showed that methionine does not affect the anodic and cathodic dissolution at all concentrations, while histidine does not affect significantly on the anodic dissolution at all concentrations. Cysteine and solutions of three amino acids in the molar ratio Cys:His:Met/1:1:1 and Cys:His:Met/1:2:1 cause intensive cathodic inhibition and anodic activation at concentrations 10−2 mol L−1 and 10−3 mol L−1 respectively.

  • 更新日期:2018-07-12
  • Hydrogen peroxide biosensor based on chitosan/2D layered double hydroxide composite for the determination of H2O2
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-23
    Jian Yuan, Sheng Xu, Hong-Yan Zeng, Xi Cao, A. Dan Pan, Gao-Fei Xiao, Peng-Xuan Ding

    The composites (LDH-CMC) composed of carboxymethyl chitosan (CMC) and 2D ZnAl layered double hydroxide (LDH) were successfully prepared using the one-step urea method; these composites were characterized by XRD, FT-IR, UV–vis DRS, SEM, BJH/BET, TG-DTG and pHzpc analyses, cyclic voltammetry, and electrochemical impedance spectroscopy. The use of CMC could impact the textural and surface chemical properties of the LDH-CMC composites, where the composites still maintained the 2D layered structure. Incorporating a moderate amount of CMC could increase both the surface area and the permanent charge density of the composites, leading to improved electrochemical performances. The LDH-CMC composite was used as a support matrix for the immobilization of horseradish peroxidase (HRP) on the glass carbon (GC) electrode to construct a biosensor that provides a biocompatible microenvironment for HRP and a pathway for H2O2 diffusion via the high surface area. The HRP biosensor displayed a satisfactory sensitivity and fast response (<3 s) toward H2O2 over a wide linear range of 0.02–6.0 mmol·L−1 with a low detection limit of 12.4 μmol·L−1, good anti-interference ability and long-term storage stability. The proposed HRP biosensor was found to be a sensitive, rapid, and disposable sensor with low cost, easy preparation and high selectivity; thus, the proposed biosensor can be used for the real-time detection of trace H2O2 in the biological, clinical and environmental fields.

  • Design and fabrication of an electrochemical aptasensor using Au nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite for rapid and sensitive detection of Staphylococcus aureus
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-27
    Saba Ranjbar, Saeed Shahrokhian

    Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S. aureus aptamer as a sensing element. The surface morphology of AuNPs/CNPs/CNFs nanocomposite was characterized with field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), dynamic light scattering (DLS) and ultraviolet-visible (UV–Vis) spectrophotometric methods. Each aptasensor modification step was monitored with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The fabricated aptasensor exhibited a wide linear dynamic range (1.2 × 101 to 1.2 × 108) CFU mL−1 with a LOD of 1 CFU mL−1 and was be capable to accurate detection and determination of Staphylococcus aureus in human blood serum as a clinical sample with a complex matrix.

  • Severe microbiologically influenced corrosion of S32654 super austenitic stainless steel by acid producing bacterium Acidithiobacillus caldus SM-1
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-23
    Yuqiao Dong, Baota Jiang, Dake Xu, Chengying Jiang, Qi Li, Tingyue Gu

    Microbiologically influenced corrosion (MIC) of S32654 (654SMO) super austenitic stainless steel (SASS) by acid producing bacterium (APB), Acidithiobacillus caldus SM-1, a strain of sulfur-oxidizing bacteria (SOB) used in biohydrometallurgy field, was investigated using electrochemical measurements and surface characterizations during a 14-day immersion test. The results indicated that S32654 SASS was susceptible to MIC by APB, and A. caldus SM-1 was capable of producing an aggressive acidic environment underneath the biofilm, resulting in the dissolution of the passive film and severe pitting attacks against S32654 SASS, which is commonly regarded as a corrosion resistant material.

  • A novel drug-free strategy of nano-pulse stimulation sequence (NPSS) in oral cancer therapy: In vitro and in vivo study
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-19
    Jinsong Guo, Feihong Dong, Lian Ding, Kaile Wang, Jue Zhang, Jing Fang

    Nano-pulse stimulation (NPS) is a novel technology to induce cancer apoptosis. In this study, based on the energy-dose effect of NPS, we designed a special NPS sequence (NPSS) with low field intensity. The effectiveness and mechanisms of NPSS on oral cancer therapy were evaluated by cell proliferation assays, microscopic investigation, JC-1 mitochondrial membrane potential assay, tumor inhibition assays, immunohistochemistry (IHC) assay, Ca2+, NOS and ROS detection assays, respectively. The results demonstrated that NPSS treatment significantly inhibited oral cancer growth in vitro and in vivo. Furthermore, we found that NPSS treatment induced an obviously apoptosis and mitochondrial membrane potential (ΔΨm) reduction in Cal-27 cells. Notably, further experiments revealed that the mechanisms of crosstalk signaling between NO, ROS and Ca2+ involvement in NPSS treatment. In conclusion, this is a proof-of-concept study that provides a potential alternative strategy for developing and applying NPSS in oral cancer therapy.

Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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