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  • 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
    更新日期:2018-08-14
  • Electrical signal propagation within and between tomato plants
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-08-07
    Alexander G. Volkov, Yuri B. Shtessel
    更新日期:2018-08-08
  • 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:2018-08-05
  • 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.

    更新日期:2018-07-23
  • 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.

    更新日期:2018-07-21
  • 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.

    更新日期:2018-07-21
  • 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.

    更新日期:2018-07-21
  • 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.

    更新日期:2018-07-21
  • 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.

    更新日期:2018-07-18
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • 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.

    更新日期:2018-07-12
  • Investigation of ceramic MFC stacks for urine energy extraction
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-03-21
    Asimina Tremouli, John Greenman, Ioannis Ieropoulos

    Two ceramic stacks, terracotta (t-stack) and mullite (m-stack), were developed to produce energy when fed with neat undiluted urine. Each stack consisted of twelve identical microbial fuel cells (MFCs) which were arranged in cascades and tested under different electrical configurations. Despite voltage reversal, the m-stack produced a maximum power of 800 μW whereas the t-stack produced a maximum of 520 μW after 62.6 h of operation. Moreover, during the operation, both systems were subject to blockage possibly due to struvite. To the Authors' best knowledge, this is the first time that such a phenomenon in ceramic MFC membranes is shown to be the direct result of sub-optimal performance, which confirms the hypothesis that ceramic membranes can continue operating long-term, if the MFCs produce maximum power (high rate of e− transfer). Furthermore, it is shown that once the ceramic membrane is blocked, it may prove difficult to recover in-situ.

    更新日期:2018-07-12
  • Biological effects in photodynamic treatment combined with electropermeabilization in wild and drug resistant breast cancer cells
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-19
    Joanna Weżgowiec, Julita Kulbacka, Jolanta Saczko, Joanna Rossowska, Grzegorz Chodaczek, Małgorzata Kotulska

    Electrochemotherapy became one of the therapeutic protocols successfully used in oncology. However, biological effects occurring in cells, especially those which are drug resistant, have not been studied thoroughly. This study presents response of wild and drug resistant breast cancer cells to classical photodynamic therapy with Photofrin or experimental photodynamic therapy with cyanine IR-775, combined with electroporation. Photodynamic reaction or electroporation alone had no cytotoxic effect, but their combination significantly disturbed cellular functions. Applying electroporation allowed the drugs to increase its accumulation, especially for a poorly permeant cyanine in drug resistant cells. FACS analysis showed that even at relatively mild electric field, ca. 90% of cells were permeabilized. High intracellular concentration of drugs triggered the cellular defense system through increased expression of glutathione S-transferase and multidrug resistance proteins (MDR1 and MRP7), particularly in drug resistant cells. Finally, expressively decreased cell metabolism and proliferation, as well as formation of apoptotic bodies and fragmentation of cells were observed after the combined treatment. The results show that electroporation can be used for effective delivery of photosensitizers, even to drug resistant breast cancer cells, which was not tested before. This shows that electro-photodynamic treatment could be a promising approach to overcome a problem of drug resistance in cancer cells.

    更新日期:2018-07-12
  • On the interaction of the highly charged peptides casocidins with biomimetic membranes
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-19
    Lucia Becucci, Giovanni Aloisi, Andrea Scaloni, Simonetta Caira, Rolando Guidelli

    Casocidin I and II (CI and CII) are structurally related antimicrobial peptides made of 39 and 31 amino acids, respectively, which derive from natural proteolytic processing of αs2-casein and adopt an ordered α-helical structure in biomimetic membranes. Their putative membrane-permeabilizing activity was investigated at Hg-supported self-assembled monolayers (SAMs) and at tethered bilayer lipid membranes (tBLMs); the latter consisted of a monolayer of 2,3,di-O-phytanyl-sn-glycerol-1-tetraethylene-glycol-d,l-α lipoic acid ester thiolipid (DPTL), with a dioleoylphosphatidylcholine (DOPC) or dioleoylphosphatidylserine (DOPS) monolayer on top of it. Interaction of CI and CII with these biomimetic membranes was studied by four electrochemical techniques at pH 3, 5.4 and 6.8. Peptide incorporation in tBLMs was attempted via scans of electrochemical impedance spectra. Experiments demonstrated that CI and CII penetrate SAMs as well as the distal DOPC monolayer of DPTL/DOPC tBLMs, but not the proximal phytanyl monolayer, with the only exception of CII at pH 5.4. Conversely, CII permeabilized DPTL/DOPS tBLMs to a moderate extent at all investigated pH values by forming holes across the membrane, but not ion channels. Structural distribution of charged residues seemed to prevent CII from having a hydrophobic side of the α-helix capable of stabilizing a regular ion channel in the lipid matrix.

    更新日期:2018-07-12
  • Nanomaterials for facilitating microbial extracellular electron transfer: Recent progress and challenges
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-05-05
    Peng Zhang, Jia Liu, Youpeng Qu, Da Li, Weihua He, Yujie Feng
    更新日期:2018-07-12
  • Bioelectrical coupling in multicellular domains regulated by gap junctions: A conceptual approach
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-04-21
    Javier Cervera, Alexis Pietak, Michael Levin, Salvador Mafe
    更新日期:2018-07-12
  • VEGF-B electrotransfer mediated gene therapy induces cardiomyogenesis in a rat model of cardiac ischemia
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-10
    Anna A. Bulysheva, Nina Burcus, Cathryn G. Lundberg, Michael P. Francis, Richard Heller

    Atherosclerosis induced myocardial infarction (MI) continues to be a major public health concern. Regenerative therapies that restore cardiac muscle cells are largely absent. The rate of cardiomyogenesis in adults is insufficient to compensate for MI damage. In this study, we explored the capacity of a gene therapy approach to promote cardiomyogenesis. We hypothesized that VEGF-B, critical during fetal heart development, could promote cardiomyogenesis in adult ischemic hearts. Gene electrotransfer (GET), a physical method of in vivo gene delivery, was adapted to the rat model of MI. Favorable pulsing parameters were then used for delivery of pVEGF-B and compared to a sham control in terms of infarct size, cardiomyocyte proliferation and presence of new cardiomyocytes. Ki67 immunoreactivity was used for proliferation analysis. Newly synthetized DNA was labeled with BrdU to identify new cells post-infarction. Cardiac troponin co-localization indicated proliferating and new cardiomyocytes histologically. Eight weeks post-treatment, GET pVEGF-B treated hearts had significantly smaller infarcts than the sham control group (p < 0.04). Proliferating and new cardiomyocytes were only present in the GET of pVEGF-B group, and absent in the controls. In summary, GET pVEGF-B promoted cardiomyogenesis post-MI, demonstrating for the first time direct evidence of myocardial regeneration post-infarction.

    更新日期:2018-07-12
  • Improved decolorization of dye wastewater in an electrochemical system powered by microbial fuel cells and intensified by micro-electrolysis
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-10
    Shuai Liang, Baogang Zhang, Jiaxin Shi, Ting Wang, Lifeng Zhang, Zhijun Wang, Cuibai Chen

    Electrochemical decolorization is of particular importance for the efficient treatment of dye wastewater. A promising electrochemical system powered by microbial fuel cells (MFCs) and intensified by Fe-C micro-electrolysis is proposed and enhanced decolorization of methyl orange (MO) is realized in this study. The decolorization efficiency reached as high as 97.1 ± 1.8% after 180 min of operation with initial MO concentration of 50 mg/L and applied voltage of 700 mV. Decolorization efficiency initially increased and then decreased with rising Fe-to-C ratio. In addition, efficiency was enhanced with the increase of aeration rate up to 6.0 L/min. Lower initial MO concentration and pH were also shown to facilitate MO decolorization. A study of mechanisms, with results from control tests and scavenger experiments indicated that MO decolorization was contributed by the indirect oxidation by various oxidizing substances, especially O2−, that were generated during the process. MO molecule was decomposed and low molecular weight compounds such as indolizine, hydrazide and thione were generated. This study advances the performance of MFC in dye wastewater treatment by combining with a standard technique.

    更新日期:2018-07-12
  • Investigation of corrosion inhibition effect and adsorption activities of Cuscuta reflexa extract for mild steel in 0.5 M H2SO4
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-07
    Akhil Saxena, Dwarika Prasad, Rajesh Haldhar

    The corrosion inhibition nature of Cuscuta reflexa fruit extract, belonging to the family of Piperaceae, has been analyzed on mild steel in 0.5 M H2SO4 with the help of weight loss studies, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques. The C. reflexa extract contains 3‑methoxy‑3,4,5,7‑tetrahydroxy flavone, which decreases the corrosion rate of mild steel in acidic medium. The maximum corrosion inhibition efficiency was observed at 500 mg/L inhibitor concentration. The adsorption study of C. reflexa extract on mild steel surface has been conducted using UV, FTIR, AFM, SEM, and DFT.

    更新日期:2018-07-12
  • Using metabolic charge production in the tricarboxylic acid cycle (QTCA) to evaluate the extracellular-electron-transfer performances of Shewanella spp.
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-07-06
    Shiue-Lin Li, Jui-Hong Yen, Kenji Kano, Shiu-Mei Liu, Chien-Liang Liu, Sheng-Shung Cheng, Hsun-Yi Chen

    Using an electrochemical cell equipped with carbon felt electrodes (poised at +0.63 V vs. SHE), the current production capabilities of two Shewanella strains—NTOU1 and KR-12—were examined under various conditions with lactate as an electron donor. The metabolic charge produced in the tricarboxylic acid cycle (QTCA) was calculated by mass-balance. The data showed a linear relation between the electric coulomb production (QEL) and QTCA with an R2 of 0.65. In addition, a large amount of pyruvate accumulation was observed at pH = 6, rendering QTCA negative. The results indicate an occurrence of an undesired cataplerotic reaction. It was also found that QTCA provides important information showing the oxygen-boosting TCA cycle and anodic-current generation of Shewanella spp. Linear dependence of the change in charge for biomass growth (4.52FΔnCell) on QTCA was also found as expressed by 4.52FΔnCell = 1.0428 QTCA + 0.0442, indicating that these two charge quantities are inherently identical under most of the experimental conditions. In the mediator-spiked experiments, the external addition of the mediators (ferricyanide, anthraquinone-2, 6-disulfonate, and riboflavin) beyond certain concentrations inhibited the activity of the TCA cycle, indicating that the oxidative phosphorylation is deactivated by excessive amounts of mediators, yet Shewanella spp. are constrained with regard to carrying out the substrate-level phosphorylation.

    更新日期:2018-07-12
  • Electrotaxis of tumor-initiating cells of H1975 lung adenocarcinoma cells is associated with both activation of stretch-activated cation channels (SACCs) and internal calcium release
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-03-27
    Yaping Li, Wai-Kin Yu, Likun Chen, Yuen-san Chan, Dandan Liu, Chi-Chun Fong, Tao Xu, Guangyu Zhu, Dong Sun, Mengsu Yang

    The metastatic potential of cancer cells is related to their migratory ability, which is influenced by in vivo microenvironment possessing specific physiochemical factors including electric properties. In the present study, we isolated two different subsets of lung adenocarcinoma H1975 cells, as side population (SP) and main population (MP). SP cells were demonstrated to have cancer stem cell characteristics. Using a microscale device to provide physiological direct-current electric field (dcEF), we investigated the electrotactic responses of the SP and MP cells. The results showed that both SP and MP cells exhibited enhanced cathodal migration ability with actin reorganization and transient intracellular calcium ions ([Ca2+]i) increase under dcEF stimulation. For SP cells, the treatment of either stretch-activated cation channels (SACCs) inhibitor or the blockage of intracellular Ca2+ release could partially inhibited dcEF-activated [Ca2+]i increase, and the concomitant treatment led to a complete inhibition. For MP cells, SACCs activation was entirely responsible for EF-activated increase of [Ca2+]i. All these results suggested that that intracellular Ca2+ activation may be associated with cancer cell tumorigenicity and metastasis.

    更新日期:2018-07-12
  • Designing strategies for operating Microbial Electrochemical Systems to clean up polluted soils under non-flooded conditions
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-03-17
    Ainara Domínguez-Garay, Abraham Esteve-Núñez

    Microbial Electrochemical Systems can be setup in soil either for the harvesting of energy from microbial metabolism (sediment microbial fuel cell, SMFC) or for the bioremediation of polluted environments (Microbial Electroremediating Cell, MERC). However, the previously thought need for this technology to be located in flooded environments, to assure the ionic contact between anode and cathode, has limited its implementation in standard soils. This work describes a new configuration that overcomes this limitation by integrating an out-of-soil cathodic chamber with a ceramic barrier so a closed circuit system can be achieved without flooding the soil. On top of harvesting energy under this new configuration we have outperformed natural bioremediation by restoring an atrazine polluted soil as proof of concept. Our results showed that >98% of the initially available atrazine was efficiency removed after 2 weeks with this new MERC configuration, in contrast with a mere 58% removal obtained under natural attenuation. Moreover, a set of toxicological tests using green algae, Salmonella typhimurium and Sorghum saccharatum strongly confirmed a marked lack of toxicity in the soil after the bioelectrochemical treatment in contrast with the natural attenuation that was unable to fulfill the non-toxic level.

    更新日期:2018-07-12
  • Cellobiose dehydrogenase hosted in lipidic cubic phase to improve catalytic activity and stability
    Bioelectrochemistry (IF 3.789) Pub Date : 2017-10-13
    Valentina Grippo, Su Ma, Roland Ludwig, Lo Gorton, Renata Bilewicz

    Lipidic cubic phase systems (LCPs) are excellent carriers for immobilized enzymes due to their biocompatibility and well-defined nanoporous structure. Lipidic cubic phases act as a convenient matrix to incorporate enzymes and hold them in the vicinity of electrode surfaces in their fully active forms. Corynascus thermophilus cellobiose dehydrogenase (CtCDH) was trapped in a monoolein cubic phase, which increased not only its stability, but also its catalytic performance with both enhanced mediated and direct electron transfer with electrodes. For studies of mediated electron transfer, three mediators with different formal potentials (E°′) were employed: horse-heart cytochrome c (cyt c), electron acceptor active with the cytochrome domain of CtCDH, and 2,6-dichlorophenolindophenol (DCPIP) as well as hexaammineruthenium(II) chloride [Ru(NH3)Cl2] both electron acceptors with the dehydrogenase domain. Ru(NH3)Cl2, having the most negative E°′ of − 0.138 V vs. Ag | AgCl at pH 7.5, gave a catalytic current for lactose oxidation of 32.10 μA cm− 2 in MOPS buffer at pH 7.5. The process carried out in the same solution but under direct electron conditions transfer resulted in a catalytic current of 9.22 μA cm− 2. Electrodes covered with CtCDH in a LCP film retained their catalytic activity after 28 days showing a slightly increased current density after 6 days.

    更新日期:2018-07-12
  • Numerical study of the effect of soft layer properties on bacterial electroporation
    Bioelectrochemistry (IF 3.789) Pub Date : 2017-09-18
    Jeffrey L. Moran, Naga Neehar Dingari, Paulo A. Garcia, Cullen R. Buie

    We present a numerical model of electroporation in a gram-positive bacterium, which accounts for the presence of a negatively charged soft polyelectrolyte layer (which may include a periplasmic space, peptidoglycan layer, cilia, flagella, and other surface appendages) surrounding its plasma membrane. We model the ion transport within and outside the soft layer using the soft layer electrokinetics-based Poisson-Nernst-Planck formalism. Additionally, we model the electroporation dynamics on the plasma membrane using the pore nucleation-based electroporation formalism developed by Krassowska and Filev. We find that ion transport within the soft layer (surface conduction), which depends on the relative importance of the soft layer charged group concentration compared to the buffer concentration, significantly alters the transmembrane voltage across the plasma membrane and hence the pore characteristics. Our numerical simulations suggest that surface conduction significantly lowers the pore number in the plasma membrane. This observation is consistent with experimental studies that show that gram-positive bacteria, in general, have lower transformation efficiencies compared to gram-negative bacteria. Our studies highlight a strong dependence of bacterial electroporation on cell envelope properties and buffer conditions, which need to be taken into consideration when designing electroporation protocols.

    更新日期:2018-07-12
  • Bacterial electroactivity and viability depends on the carbon nanotube-coated sponge anode used in a microbial fuel cell
    Bioelectrochemistry (IF 3.789) Pub Date : 2018-02-27
    Hanyue Ma, Tian Xia, Congcong Bian, Huihui Sun, Zhuang Liu, Chao Wu, Xia Wang, Ping Xu

    The anode material is vital to improve the power generation of a microbial fuel cell (MFC). In this study, a carbon nanotube (CNT)-coated sponge with macro-porous structure, high surface area, and high conductivity was constructed as an anode to encapsulate Escherichia coli K12 (E. coli K12) cells. To achieve high power generation of the MFC, the optimal concentration of the CNT coating the sponge was found to be 30 mg mL−1. At this concentration, a maximum power density of 787 W m−3 and a chemical oxygen demand (COD) removal of 80.9% were obtained with a long stable electricity generation process in batch mode. This indicates that the biofilm on the CNT (30 mg mL−1)-coated sponge possessed excellent electroactivity and stability. Scanning electron microscope (SEM) images confirmed that the CNT-coated sponge provided a suitable microenvironment for E. coli K12 cells to maintain their attachment and colonization. Additionally, a CNT-dependent viability phenomenon of the E. coli K12 cells was discovered after electricity generation. This CNT-dependent viability of the E. coli K12 cells was stable and sustainable after storage at −20 °C in a milk tube for one year.

    更新日期:2018-06-03
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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