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  • Corrosion effect of Bacillus cereus on X80 pipeline steel in a Beijing soil environment
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-24
    Hongxia Wan, Dongdong Song, Dawei Zhang, Cuiwei Du, Dake Xu, Zhiyong Liu, De Ding, Xiaogang Li

    The corrosion of X80 pipeline steel in the presence of Bacillus cereus (B. cereus) was studied through electrochemical and surface analyses and live/dead staining. Scanning electron microscopy and live/dead straining results showed that a number of B. cereus adhered to the X80 steel. Electrochemical impedance spectroscopy showed that B. cereus could accelerate the corrosion of X80 steel. In addition, surface morphology observations indicated that B. cereus could accelerate pitting corrosion in X80 steel. The depth of the largest pits due to B. cereus was approximately 11.23 μm. Many pits were found on the U-shaped bents and cracks formed under stress after 60 days of immersion in the presence of B. cereus. These indicate that pitting corrosion can be accelerated by B. cereus. X-ray photoelectron spectroscopy results revealed that NH4+ existed on the surface of X80 steel. B. cereus is a type of nitrate-reducing bacteria and hence the corrosion mechanism of B. cereus may involve nitrate reduction on the X80 steel.

  • Impact of the start-up process on the microbial communities in biocathodes for electrosynthesis
    Bioelectrochemistry (IF 3.346) Pub Date : 2018-01-07
    Raúl Mateos, Ana Sotres, Raúl M. Alonso, Adrián Escapa, Antonio Morán

    This study seeks to understand how the bacterial communities that develop on biocathodes are influenced by inocula diversity and electrode potential during start-up. Two different inocula are used: one from a highly diverse environment (river mud) and the other from a low diverse milieu (anaerobic digestion). In addition, both inocula were subjected to two different polarising voltages: oxidative (+0.2 V vs. Ag/AgCl) and reductive (−0.8 V vs. Ag/AgCl).Bacterial communities were analysed by means of high throughput sequencing. Possible syntrophic interactions and competitions between archaea and eubacteria were described together with a discussion of their potential role in product formation and current production. The results confirmed that reductive potentials lead to an inconsistent start-up procedure regardless of the inoculum used. However, imposing oxidative potentials help to quickly develop an electroactive biofilm ready to withstand reductive potentials (i.e. biocathodic operation). The microbial structure that finally developed on them was highly dependent on the raw community present in the inoculum. Using a non-specialised inoculum resulted in a highly specialised biofilm, which was accompanied by an improved performance in terms of consumed current and product generation. Interestingly, a much more specialised inoculum promoted a rediversification in the biofilm, with a lower general cell performance.

  • The role of sulfides in stress-induced changes of Eh in Escherichia coli cultures
    Bioelectrochemistry (IF 3.346) Pub Date : 2018-01-03
    Alexey Tyulenev, Galina Smirnova, Nadezda Muzyka, Vadim Ushakov, Oleg Oktyabrsky
  • Electrochemical antioxidant screening based on a chitosan hydrogel
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-27
    Li Fu, Aiwu Wang, Fucong Lyv, Guosong Lai, Huaiwei Zhang, Jinhong Yu, Cheng-Te Lin, Aimin Yu, Weitao Su
  • The electrochemical behavior of a FAD dependent glucose dehydrogenase with direct electron transfer subunit by immobilization on self-assembled monolayers
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-20
    Inyoung Lee, Noya Loew, Wakako Tsugawa, Chi-En Lin, David Probst, Jeffrey T. La Belle, Koji Sode

    Continuous glucose monitoring (CGM) is a vital technology for diabetes patients by providing tight glycemic control. Currently, many commercially available CGM sensors use glucose oxidase (GOD) as sensor element, but this enzyme is not able to transfer electrons directly to the electrode without oxygen or an electronic mediator. We previously reported a mutated FAD dependent glucose dehydrogenase complex (FADGDH) capable of direct electron transfer (DET) via an electron transfer subunit without involving oxygen or a mediator. In this study, we investigated the electrochemical response of DET by controlling the immobilization of DET-FADGDH using 3 types of self-assembled monolayers (SAMs) with varying lengths. With the employment of DET-FADGDH and SAM, high current densities were achieved without being affected by interfering substances such as acetaminophen and ascorbic acid. Additionally, the current generated from DET-FADGDH electrodes decreased with increasing length of SAM, suggesting that the DET ability can be affected by the distance between the enzyme and the electrode. These results indicate the feasibility of controlling the immobilization state of the enzymes on the electrode surface.

  • A sandwich-type electrochemical immunoassay for ultrasensitive detection of non-small cell lung cancer biomarker CYFRA21-1
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-13
    Yan Zeng, Jing Bao, Yanan Zhao, Danqun Huo, Mei Chen, Yanli Qi, Mei Yang, Huanbao Fa, Changjun Hou

    Many studies confirm that the aberrant expression of Cytokeratin 19 fragment 21-1 (CYFRA21-1) is highly correlated with non-small cell lung cancer (NSCLC), especially for squamous cell carcinoma. Herein, we report a sandwich-type electrochemical immunosensor based on signal amplification strategy of multiple nanocomposites to test CYFRA21-1 selectively and sensitively. The proposed immunosensor fabricated by three-dimensional graphene (3D–G), chitosan (CS) and glutaraldehyde (GA) composite on the glass carbon electrode (GCE) with a large surface area is prepared to immobilize primary antibodies (Ab1) and provide excellent conductivity. To further amplify the electrochemical signal, the trace tag on the foundation of gold nanoparticles (AuNPs) is coated with amino-functionalized carbon nanotube (MWCNT-NH2) nanocomposite through thionine linking, which provides more amino groups to capture more horseradish peroxidase-labeled antibodies (HPR-Ab2) and enhances the conductivity. Under optimal conditions, the developed immunosensor exhibits excellent analytical performance for the determination of CYFRA21-1 with a wide linear range from 0.1 to 150 ng·mL− 1 and a low detection limit (LOD) of 43 pg·mL− 1. Furthermore, satisfactory results are obtained for the determination of CYFRA21-1 in real clinical serum samples, indicating the potential of the immunoassay to be applied in clinical analysis.

  • Reductive electrografting of in situ produced diazopyridinium cations: Tailoring the interface between carbon electrodes and electroactive bacterial films
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-16
    Hassiba Smida, Estelle Lebègue, Jean-François Bergamini, Frédéric Barrière, Corinne Lagrost
  • Rose petal and P123 dual-templated macro-mesoporous TiO2 for a hydrogen peroxide biosensor
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-19
    Xu Wu, Huanhuan Zhang, Kejing Huang, Yan Zeng, Zhihong Zhu
  • 更新日期:2017-12-18
  • In vitro electroporation detection methods – An overview
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-16
    Tina Batista Napotnik, Damijan Miklavčič

    Exposing cells to an electric field leads to electroporation of the cell membrane which has already been explored and used in a number of applications in medicine and food biotechnology (e.g. electrochemotherapy, gene electrotransfer, extraction of biomolecules). The extent of electroporation depends on several conditions, including pulse parameters, types of cells and tissues, surrounding media, temperature etc. Each application requires a specific level of electroporation, so it must be explored in advance by employing methods for detecting electroporation. Electroporation detection is most often done by measuring increased transport of molecules across the membrane, into or out of the cell. We review here various methods of electroporation detection, together with their advantages and disadvantages. Electroporation detection can be carried out by using dyes (fluorophores or colour stains) or functional molecules, by measuring the efflux of biomolecules, by impedance measurements and voltage clamp techniques as well as by monitoring cell swelling. This review describes methods of detecting cell membrane electroporation in order to help researchers choose the most suitable ones for their specific experiments, considering available equipment and experimental conditions.

  • Effect of anode polarization on biofilm formation and electron transfer in Shewanella oneidensis/graphite felt microbial fuel cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-31
    David Pinto, Thibaud Coradin, Christel Laberty-Robert

    In microbial fuel cells, electricity generation is assumed by bacterial degradation of low-grade organics generating electrons that are transferred to an electrode. The nature and efficiency of the electron transfer from the bacteria to the electrodes are determined by several chemical, physical and biological parameters. Specifically, the application of a specific potential at the bioanode has been shown to stimulate the formation of an electro-active biofilm, but the underlying mechanisms remain poorly understood. In this study, we have investigated the effect of an applied potential on the formation and electroactivity of biofilms established by Shewanella oneidensis bacteria on graphite felt electrodes in single- and double-chamber reactor configurations in oxic conditions. Using amperometry, cyclic voltammetry, and OCP/Power/Polarization curves techniques, we showed that a potential ranging between − 0.3 V and + 0.5 V (vs. Ag/AgCl/KCl sat.) and its converse application to a couple of electrodes leads to different electrochemical behaviors, anodic currents and biofilm architectures. For example, when the bacteria were confined in the anodic compartment of a double-chamber cell, a negative applied potential (− 0.3 V) at the bioanode favors a mediated electron transfer correlated with the progressive formation of a biofilm that fills the felt porosity and bridges the graphite fibers. In contrast, a positive applied potential (+ 0.3 V) at the bioanode stimulates a direct electron transfer resulting in the fast-bacterial colonization of the fibers only. These results provide significant insight for the understanding of the complex bacteria-electrode interactions in microbial fuel cells.

  • Peptide-based biosensors: From self-assembled interfaces to molecular probes in electrochemical assays
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-23
    Mihaela Puiu, Camelia Bala

    Redox-tagged peptides have emerged as functional materials with multiple applications in the area of sensing and biosensing applications due to their high stability, excellent redox properties and versatility of biomolecular interactions. They allow direct observation of molecular interactions in a wide range of affinity and enzymatic assays and act as electron mediators. Short helical peptides possess the ability to self-assemble in specific configurations with the possibility to develop in highly-ordered, stable 1D, 2D and 3D architectures in a hierarchical controlled manner. We provide here a brief overview of the electrochemical techniques available to study the electron transfer in peptide films with particular interest in developing biosensors with immobilized peptide motifs, for biological and clinical applications.

  • Copper-phospholipid interaction at cell membrane model hydrophobic surfaces
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-11
    Marina Mlakar, Vlado Cuculić, Sanja Frka, Blaženka Gašparović
  • Electrode-based AC electrokinetics of proteins: A mini-review
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-23
    Eva-Maria Laux, Frank F. Bier, Ralph Hölzel

    Employing electric phenomena for the spatial manipulation of bioparticles from whole cells down to dissolved molecules has become a useful tool in biotechnology and analytics. AC electrokinetic effects like dielectrophoresis and AC electroosmosis are increasingly used to concentrate, separate and immobilize DNA and proteins. With the advance of photolithographical micro- and nanofabrication methods, novel or improved bioanalytical applications benefit from concentrating analytes, signal enhancement and locally controlled immobilization by AC electrokinetic effects. In this review of AC electrokinetics of proteins, the respective studies are classified according to their different electrode geometries: individual electrode pairs, interdigitated electrodes, quadrupole electrodes, and 3D configurations of electrode arrays. Known advantages and disadvantages of each layout are discussed.

  • A study of microbial communities on terracotta separator and on biocathode of air breathing microbial fuel cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-11
    Laura Rago, Sarah Zecchin, Stefania Marzorati, Andrea Goglio, Lucia Cavalca, Pierangela Cristiani, Andrea Schievano
  • Ennoblement, corrosion, and biofouling in brackish seawater: Comparison between six stainless steel grades
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-05
    E. Huttunen-Saarivirta, P. Rajala, M. Marja-aho, J. Maukonen, E. Sohlberg, L. Carpén

    In this work, six common stainless steel grades were compared with respect to ennoblement characteristics, corrosion performance and tendency to biofouling in brackish sea water in a pilot-scale cooling water circuit. Two tests were performed, each employing three test materials, until differences between the materials were detected. Open circuit potential (OCP) was measured continuously in situ. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were conducted before and after the tests. Exposed specimens were further subjected to examinations by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), and the biofouling was studied using epifluorescence microscopy, quantitative polymerase chain reaction (qPCR) and high-throughput sequencing (HTP sequencing). The results revealed dissimilarities between the stainless steel grades in corrosion behaviour and biofouling tendency. The test material that differed from the most of the other studied alloys was grade EN 1.4162. It experienced fastest and most efficient ennoblement of OCP, its passive area shrank to the greatest extent and the cathodic reaction was accelerated to a significant degree by the development of biofilm. Furthermore, microbiological analyses revealed that bacterial community on EN 1.4162 was dominated by Actinobacteria, whereas on the other five test materials Proteobacteria was the main bacterial phylum.

  • A novel electrochemical aptasensor for highly sensitive and quantitative detection of the streptomycin antibiotic
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-15
    Kazhal Ghanbari, Mahmoud Roushani

    In the present study, we report a facile approach to employ gold nanoparticle (AuNPs) and thiol graphene quantum dots (GQD-SH) as the nanomaterial for ultrasensitive detection of streptomycin (STR). Based on this strategy, a GQD-SH was immobilized onto the surface of a glassy carbon electrode (GCE). AuNPs have been immobilized on SH groups of GQDs through bonding formation of AuS and Apt have been loaded on the electrode surface through the interaction between thiol group of aptamer. By incubating STR as a target onto the surface of the prepared Apt/AuNPs/GQD-SH/GCE as a proposed nanoaptasensor, the Apt/STR complex was formed and the changes of the electrochemical signal were evaluated with the EIS technique. The proposed nanoaptasensor showed wide linear range from 0.1 to 700 pg ml− 1. Finally, the proposed nanoaptasensor was successfully applied for the determination of STR in real samples and satisfactory results were obtained.

  • Nitrate removal from pharmaceutical wastewater using microbial electrochemical system supplied through low frequency-low voltage alternating electric current
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-21
    Edris Hoseinzadeh, Abbas Rezaee, Mahdi Farzadkia

    In this study, a microbial electrochemical system (MES) was designed to evaluate the effects of a low frequency-low voltage alternating electrical current on denitrification efficacy in the presence of ibuprofen as a low biodegradable organic carbon source. Cylindrical carbon cloth and stainless steel mesh electrodes containing a consortium of heterotrophic and autotrophic bacteria were mounted in the wall of the designed laboratory-scale bioreactor. The effects of inlet nitrate concentration (50–800 mg L− 1), retention time (2.5–24 h), waveform magnitude (0.1–9.6 Vp − p), adjustable direct current voltage added to offset voltage (0.1–4.9 V), alternating current frequency (10–60 Hz), and waveforms (sinusoidal, square, and ramp) were studied in this work. The results showed that the proposed system removes 800 mg L− 1 nitrate up to 95% during 6.5 h. Optimum conditions were obtained in the 8 Vp − p using a frequency of 10 Hz of a sinusoidal waveform. The morphology studies confirmed bacterial morphology change when applying the alternating current. Dehydrogenase activity of biofilms formed on surface of stainless steel electrodes increased to 15.24 μgTF mgbiomass cm− 2 d. The maximum bacterial activity was obtained at a voltage of 8 Vp − p. The experimental results revealed that the MES using a low frequency-low voltage alternating electrical current is a promising technique for nitrate removal from pharmaceutical wastewaters in the presence of low biodegradability of carbon sources such as ibuprofen.

  • Interpreting microbiologically assisted cracking with Ee-pH diagrams
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-16
    Tangqing Wu, Cheng Sun, Wei Ke

    Although many mechanisms have been proposed to explain the microbiologically assisted cracking (MAC) of steel and copper, a theoretical interpretation is necessary. In this paper, we attempt to give a theoretical interpretation of sulfate/nitrate reducing bacteria (SRB/NRB)-assisted cracking using Ee-pH diagrams. Under the combined actions of SRB/NRB and external stress, the cell potential (Ecell) and the corrosion current density of the corrosion reaction increase, such that the corrosion reactions become more thermodynamically favorable. This is the nature of MAC. Nitrate is a far more potent oxidant than sulfate, and thus, the NRB-assisted cracking of iron is a more thermodynamically favorable process than the SRB-assisted cracking. Furthermore, the thermodynamic interpretation is attempted to implicate into the classical stress corrosion cracking mechanisms of pipeline steel.

  • Adsorption/desorption of biomacromolecules involved in catalytic hydrogen evolution
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-29
    Slađana Strmečki, Emil Paleček
  • Determination of the formal redox potentials of the cyanhaemoglobin/cyanmethaemoglobin and the myoglobin/metmyoglobin couples at neutral pH
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-11-27
    Leila Mahmoudi, Felix Zelder, Reinhard Kissner

    Determination of a representative formal redox potential of the Fe(II)/Fe(III) redox couple in cyanhaemoglobin, at pH = 7 and related to the state in solution, was the objective of this work. It was achieved at low concentrations of the protein (5 μM) to circumvent undesired adsorption. Square-wave voltammetry instead of classical cyclic voltammetry was applied because this method is more sensitive and provides information on the formal redox potential and reversibility, even for rapid processes. We obtained E°′ = − 0.12 ± 0.01 V for cyanhaemoglobin and E°′ = − 0.10 ± 0.01 V, vs. SHE, for myoglobin in comparison. These values differ by only 20 mV because the two Fe(II)/Fe(III) redox centres are embedded in closely resembling chemical environments. The small difference is probably owed to the additional axially coordinating cyanide ligand in cyanmethaemoglobin which slightly favours the Fe(III) state in the haem macrocycle.

  • Sensitive detection of pyoverdine with an electrochemical sensor based on electrochemically generated graphene functionalized with gold nanoparticles
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-05
    Islem Gandouzi, Mihaela Tertis, Andreea Cernat, Amina Bakhrouf, Maria Coros, Stela Pruneanu, Cecilia Cristea
  • Electrocatalytic CO2 reduction catalyzed by nitrogenase MoFe and FeFe proteins
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-05
    Bo Hu, Derek F. Harris, Dennis R. Dean, T. Leo Liu, Zhi-Yong Yang, Lance C. Seefeldt

    Nitrogenases catalyze biological dinitrogen (N2) reduction to ammonia (NH3), and also reduce a number of non-physiological substrates, including carbon dioxide (CO2) to formate (HCOO−) and methane (CH4). Three versions of nitrogenase are known (Mo-, V-, and Fe-nitrogenase), each showing different reactivities towards various substrates. Normally, electrons for substrate reduction are delivered by the Fe protein component of nitrogenase, with energy coming from the hydrolysis of 2 ATP to 2 ADP + 2 Pi for each electron transferred. Recently, it has been demonstrated that energy and electrons can be delivered from an electrode to the catalytic nitrogenase MoFe-protein without the need for Fe protein or ATP hydrolysis. Here, it is demonstrated that both the MoFe- and FeFe-protein can be immobilized as a polymer layer on an electrode and that electron transfer mediated by cobaltocene can drive CO2 reduction to formate in this system. It was also found that the FeFe-protein diverts a greater percentage of electrons to CO2 reduction versus proton reduction compared to the MoFe-protein. Quantification of electron flow to products exhibited Faradaic efficiencies of CO2 conversion to formate of 9% for MoFe protein and 32% for FeFe-protein, with the remaining electrons going to proton reduction to make H2.

  • Effects of shock waves, ultraviolet light, and electric fields from pulsed discharges in water on inactivation of Escherichia coli
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-02
    Bing Sun, Yanbin Xin, Xiaomei Zhu, Zhiying Gao, Zhiyu Yan, Takayuki Ohshima

    In this work, the bacterial inactivation effects of shock waves, ultraviolet (UV) light, and electric field produced by high-voltage pulsed discharge in liquid with needle-plate configurations were studied. The contributions of each effect on the bacterial killing ratio in the discharge process were obtained individually by modifying reactor type and usage of glass, quartz, and black balloons. The results showed that the location from the discharge center axis significantly influenced the effects of shock waves and electric fields, although the effect of UV light was not affected by the location in the reactor. The effects of shock waves and electric fields were improved by decreasing the distance from the discharge center axis. Under this experimental condition, the effects of shock waves, UV light, and electric fields produced by discharges on bacterial inactivation were approximately 36.1%, 30.8%, 12.7%, respectively. Other contributions seemed to be due to activated species.

  • Study of lipid peroxidation and ascorbic acid protective role in large unilamellar vesicles from a new electrochemical performance
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-06
    M. Fátima Barroso, M. Alejandra Luna, Fernando Moyano, Cristina Delerue-Matos, N. Mariano Correa, Patricia G. Molina
  • Biofuel cells – Activation of micro- and macro-electronic devices
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-07
    Maria Gamella, Ashkan Koushanpour, Evgeny Katz
  • Surpassing the current limitations of high purity H2 production in microbial electrolysis cell (MECs): Strategies for inhibiting growth of methanogens
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-14
    Abudukeremu Kadier, Mohd Sahaid Kalil, Kuppam Chandrasekhar, Gunda Mohanakrishna, Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Gopalakrishnan Kumar, Arivalagan Pugazhendhi, Periyasamy Sivagurunathan
  • Immobilization of methotrexate anticancer drug onto the graphene surface and interaction with calf thymus DNA and 4T1 cancer cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-08-18
    Reza Karimi Shervedani, Hadiseh Mirhosseini, Marzieh Samiei Foroushani, Mostafa Torabi, Fatemeh Rahnemaye Rahsepar, Leila Norouzi-Barough
  • Electropermeabilization by uni- or bipolar nanosecond electric pulses: The impact of extracellular conductivity
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-08-25
    Elena C. Gianulis, Maura Casciola, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

    Cellular effects caused by nanosecond electric pulses (nsEP) can be reduced by an electric field reversal, a phenomenon known as bipolar cancellation. The reason for this cancellation effect remains unknown. We hypothesized that assisted membrane discharge is the mechanism for bipolar cancellation. CHO-K1 cells bathed in high (16.1 mS/cm; HCS) or low (1.8 mS/cm; LCS) conductivity solutions were exposed to either one unipolar (300-ns) or two opposite polarity (300 + 300-ns; bipolar) nsEP (4–40 kV/cm) with increasing interpulse intervals (0.1–50 μs). Time-lapse YO-PRO-1 (YP) uptake revealed enhanced membrane permeabilization in LCS compared to HCS at all tested voltages. The time-dependence of bipolar cancellation was similar in both solutions, using either identical (22 kV/cm) or isoeffective nsEP treatments (12 and 32 kV/cm for LCS and HCS, respectively). However, cancellation was significantly stronger in LCS when the bipolar nsEP had no, or very short (< 1 μs), interpulse intervals. Finally, bipolar cancellation was still present with interpulse intervals as long as 50 μs, beyond the time expected for membrane discharge. Our findings do not support assisted membrane discharge as the mechanism for bipolar cancellation. Instead they exemplify the sustained action of nsEP that can be reversed long after the initial stimulus.

  • Bioelectrochemical sulphate reduction on batch reactors: Effect of inoculum-type and applied potential on sulphate consumption and pH
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-08-25
    Manuel A. Gacitúa, Enyelbert Muñoz, Bernardo González

    Microbial electrolysis batch reactor systems were studied employing different conditions, paying attention on the effect that biocathode potential has on pH and system performance, with the overall aim to distinguish sulphate reduction from H2 evolution. Inocula from pure strains (Desulfovibrio paquesii and Desulfobacter halotolerans) were compared to a natural source conditioned inoculum. The natural inoculum possess the potential for sulphate reduction on serum bottles experiments due to the activity of mutualistic bacteria (Sedimentibacter sp. and Bacteroides sp.) that assist sulphate-reducing bacterial cells (Desulfovibrio sp.) present in the consortium. Electrochemical batch reactors were monitored at two different potentials (graphite-bar cathodes poised at − 900 and − 400 mV versus standard hydrogen electrode) in an attempt to isolate bioelectrochemical sulphate reduction from hydrogen evolution. At − 900 mV all inocula were able to reduce sulphate with the consortium demonstrating superior performance (SO42 − consumption: 25.71 g m− 2 day− 1), despite the high alkalinisation of the media. At − 400 mV only the pure Desulfobacter halotolerans inoculated system was able to reduce sulphate (SO42 − consumption: 17.47 g m− 2 day− 1) and, in this potential condition, pH elevation was less for all systems, confirming direct (or at least preferential) bioelectrochemical reduction of sulphate over H2 production.

  • Temperature, inocula and substrate: Contrasting electroactive consortia, diversity and performance in microbial fuel cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-07-22
    E.S. Heidrich, J. Dolfing, M.J. Wade, W.T. Sloan, C. Quince, T.P. Curtis
  • Study on the oxygen reduction reaction catalyzed by a cold-tolerant marine strain phylogenetically related to Erythrobacter citreus
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-08
    Lianqiang Li, Fei Ding, Lin Sang, Jiaquan Liu, Duolu Mao, Xingjiang Liu, Qiang Xu

    As the development of marine economy, the submarine battery with the seawater electrolyte has obtained more and more attentions. Owing to the conventional electrochemical catalysts of the cathodes in seawater battery are expensive, it is to seek the new biological catalysts to improve the electrochemical performance of the cathode and reduce the cost of seawater battery. A novel marine bacterial strain (Strain SQ-32) phylogenetically related to the Erythrobacter citreus strain has been isolated from the sea-bed sludge in the Yellow Sea of China successfully. The electrochemical measurements, which include the cyclic voltammetry, potentiostatic polarization, and electrochemical impedance spectroscopy, have been conducted in synthetic seawater. The electrochemical testing results show that the Strain SQ-32 is a cold-tolerant bacterium, which may exhibit a catalytic activity for the ORR in synthetic seawater at a freezing temperature. The SEM photo demonstrates that the Strain SQ-32 displays a rod-shaped characteristic, which has a diameter of 0.4 μm and a length of about 1–2.5 μm. By the testing of Gram staining, the Strain SQ-32 has been identified as a Gram-negative bacterium. The chemical analytical result reveals that the bacterium cell of Strain SQ-32 contains 1.92 mg g− 1 (DCW) of coenzyme Q10, which is a possible impact factor on the electro-catalytic effect on the Strain SQ-32. The exploitation of Strain SQ-32 may boost the development of the biocathode of seawater battery at a low temperature.

  • 更新日期:2017-12-14
  • Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-08
    Lynn Carr, Sylvia M. Bardet, Delia Arnaud-Cormos, Philippe Leveque, Rodney P. O'Connor

    Cytosolic, synthetic chemical calcium indicators are typically used to visualise the rapid increase in intracellular calcium ion concentration that follows nanosecond pulsed electric field (nsPEF) application. This study looks at the application of genetically encoded calcium indicators (GECIs) to investigate the spatiotemporal nature of nsPEF-induced calcium signals using fluorescent live cell imaging. Calcium responses to 44 kV/cm, 10 ns pulses were observed in U87-MG cells expressing either a plasma membrane targeted GECI (GCaMP5-G), or one cytosolically expressed (GCaMP6-S), and compared to the response of cells loaded with cytosolic or plasma membrane targeted chemical calcium indicators. Application of 100 pulses, to cells containing plasma membrane targeted indicators, revealed a wave of calcium across the cell initiating at the cathode side. A similar spatial wave was not observed with cytosolic indicators with mobile calcium buffering properties. The speed of the wave was related to pulse application frequency and it was not propagated by calcium induced calcium release.

  • 更新日期:2017-12-14
  • Dielectric properties of isolated adrenal chromaffin cells determined by microfluidic impedance spectroscopy
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-05
    A.C. Sabuncu, M. Stacey, G.L. Craviso, N. Semenova, P.T. Vernier, N. Leblanc, I. Chatterjee, J. Zaklit

    Knowledge of the dielectric properties of biological cells plays an important role in numerical models aimed at understanding how high intensity ultrashort nanosecond electric pulses affect the plasma membrane and the membranes of intracellular organelles. To this end, using electrical impedance spectroscopy, the dielectric properties of isolated, neuroendocrine adrenal chromaffin cells were obtained. Measured impedance data of the cell suspension, acquired between 1 kHz and 20 MHz, were fit into a combination of constant phase element and Cole-Cole models from which the effect of electrode polarization was extracted. The dielectric spectrum of each cell suspension was fit into a Maxwell-Wagner mixture model and the Clausius-Mossotti factor was obtained. Lastly, to extract the cellular dielectric parameters, the cell dielectric data were fit into a granular cell model representative of a chromaffin cell, which was based on the inclusion of secretory granules in the cytoplasm. Chromaffin cell parameters determined from this study were the cell and secretory granule membrane specific capacitance (1.22 and 7.10 μF/cm2, respectively), the cytoplasmic conductivity, which excludes and includes the effect of intracellular membranous structures (1.14 and 0.49 S/m, respectively), and the secretory granule milieu conductivity (0.35 S/m). These measurements will be crucial for incorporating into numerical models aimed at understanding the differential poration effect of nanosecond electric pulses on chromaffin cell membranes.

  • High frequency electroporation efficiency is under control of membrane capacitive charging and voltage potential relaxation
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-14
    Vitalij Novickij, Paulius Ruzgys, Audrius Grainys, Saulius Šatkauskas

    The study presents the proof of concept for a possibility to achieve a better electroporation in the MHz pulse repetition frequency (PRF) region compared to the conventional low frequency protocols. The 200 ns × 10 pulses bursts of 10–14 kV/cm have been used to permeabilize Chinese hamster ovary (CHO) cells in a wide range (1 Hz–1 MHz) of PRF. The permeabilization efficiency was evaluated using fluorescent dye assay (propidium iodide) and flow cytometry. It was determined that a threshold PRF exists when the relaxation of the cell transmembrane potential is longer than the delay between the consequent pulses, which results in accumulation of the charge on the membrane. For the CHO cells and 0.1 S/m electroporation medium, this phenomenon is detectable in the 0.5–1 MHz range. It was shown that the PRF is an important parameter that could be used for flexible control of electroporation efficiency in the high frequency range.

  • Dynamical modeling of tissue electroporation
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-05
    Damien Voyer, Aude Silve, Lluis M. Mir, Riccardo Scorretti, Clair Poignard

    In this paper, we propose a new dynamical model of tissue electroporation. The model is based on equivalent circuit approach at the tissue. Considering two current densities from cells and extracellular matrix, we identify the macroscopic homogenised contribution of the cell membranes. Our approach makes it possible to define a macroscopic homogenised electric field and a macroscopic homogenised transmembrane potential. This provides a direct link between the cell scale electroporation models and the tissue models. Finite element method adapted to the new non-linear model of tissue electroporation is used to compare experiments with simulations. Adapting the phenomenological electroporation model of Leguèbe et al. to the tissue scale, we calibrate the tissue model with experimental data. This makes two steps appear in the tissue electroporation process, as for cells. The new insight of the model lies in the well-established equivalent circuit approach to provide a homogenised version of cell scale models. Our approach is tightly linked to numerical homogenisation strategies adapted to bioelectrical tissue modeling.

  • On the relationship between long-distance and heterogeneous electron transfer in electrode-grown Geobacter sulfurreducens biofilms
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-18
    Matthew D. Yates, Brian J. Eddie, Nikolai Lebedev, Nicholas J. Kotloski, Sarah M. Strycharz-Glaven, Leonard M. Tender

    The ability of certain microorganisms to live in a multi-cell thick, electrode-grown biofilm by utilizing the electrode as a metabolic electron acceptor or donor requires electron transfer across cell membranes, through the biofilm, and across the biofilm/electrode interface. Even for the most studied system, anode-grown Geobacter sulfurreducens, the mechanisms underpinning each process and how they connect is largely unresolved. Here we report on G. sulfurreducens biofilms grown across the gap separating two electrodes by maintaining one electrode at 0.300 V vs. Ag/AgCl (0.510 V vs. SHE) to act as a sustained metabolic electron acceptor while the second electrode was at open circuit. The poised electrode exhibited the characteristic current-time profile for electrode-dependent G. sulfurreducens biofilm growth. The open circuit potential (OCP) of the second electrode however increased after initially decreasing for 1.5–2 days. The increase in OCP is taken to indicate the point at which the growing biofilm bridged the gap between the electrodes, enabling cells in contact with the open circuit electrode to utilize the poised electrode as an electron acceptor. After but not prior to reaching this point, the second electrode was able to act as a sustainable electron acceptor immediately after being placed under potential control without requiring further time to develop. These results indicate that heterogeneous ET (H-ET) across the biofilm/electrode interface and long-distance ET (LD-ET) through the biofilm are highly correlated, if not inseparable, and may share many common components.

  • In vitro development and in vivo application of a platinum-based electrochemical device for continuous measurements of peripheral tissue oxygen
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-22
    Niall J. Finnerty, Fiachra B. Bolger

    Acute limb ischaemia is caused by compromised tissue perfusion and requires immediate attention to reduce the occurrence of secondary complications that could lead to amputation or death. To address this, we have developed a novel platinum (Pt)-based electrochemical oxygen (O2) device for future applications in clinical monitoring of peripheral tissue ischaemia. The effect of integrating a Pt pseudo-reference electrode into the O2 device was investigated in vitro with an optimum reduction potential of − 0.80 V. A non-significant (p = 0.11) decrease in sensitivity was recorded when compared against an established Pt-based O2 sensor operating at − 0.65 V. Furthermore, a biocompatible clinical sensor (ClinOX) was designed, demonstrating excellent linearity (R2 = 0.99) and sensitivity (1.41 ± 0.02 nA μM− 1) for O2 detection. Significant rapid decreases in the O2 current during in vivo ischaemic insults in rodent limbs were reported for Pt-Pt (p < 0.001) and ClinOX (p < 0.01) and for ClinOX (p < 0.001) in porcine limbs. Ex vivo sensocompatibility investigations identified no significant difference (p = 0.08) in sensitivity values over 14 days of exposure to tissue homogenate. The Pt-Pt based O2 design demonstrated high sensitivity for tissue ischaemia detection and thus warrants future clinical investigation.

  • Electrical current generation in microbial electrolysis cells by hyperthermophilic archaea Ferroglobus placidus and Geoglobus ahangari
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-02
    Yasemin D. Yilmazel, Xiuping Zhu, Kyoung-Yeol Kim, Dawn E. Holmes, Bruce E. Logan
  • Comparable effectiveness and immunomodulatory actions of oxaliplatin and cisplatin in electrochemotherapy of murine melanoma
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-03
    Katja Ursic, Spela Kos, Urska Kamensek, Maja Cemazar, Janez Scancar, Simon Bucek, Simona Kranjc, Barbara Staresinic, Gregor Sersa
  • Effect of the anode potential on the physiology and proteome of Shewanella oneidensis MR-1
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-03
    Christy Grobbler, Bernardino Virdis, Amanda Nouwens, Falk Harnisch, Korneel Rabaey, Philip L. Bond

    Shewanella species respire using iron and manganese oxides as well as electrodes as solid terminal electron acceptors. Shewanella oneidenis MR-1 exploits mediated as well as direct extracellular electron transfer (EET) modes to transfer electrons at different formal potentials. These different EET modes at different potentials may utilise alternate electron transfer pathways. Therefore, we investigated how different anode potentials, providing different maximum microbial energy gains impacted S. oneidensis microbial physiology. Using quantitative proteomics, comparative analysis of the cellular variations to different anode potentials was performed. A label-free proteomic mass spectrometric analysis method, SWATH-MS, was used to gather quantitative information to determine physiological changes of Shewanella oneidensis MR-1 grown at different anodic potentials. S. oneidensis was cultured and grown in electrochemical cells at the set anode potentials of + 0.71 V, + 0.21 V & − 0.19 V versus SHE reference electrode, while the current production was monitored. At maximum current, electrodes were removed and whole-cell proteins extracted. Subsequent SWATH-MS analysis revealed information on 740 identified proteins across the three electrode potentials. For the first time, we show the abundance of S. oneidensis electron transfer proteins differs with electrode potential.

  • Temperature dependence of bioelectrochemical CO2 conversion and methane production with a mixed-culture biocathode
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-02
    Hou-Yun Yang, Bai-Ling Bao, Jing Liu, Yuan Qin, Yi-Ran Wang, Kui-Zu Su, Jun-Cheng Han, Yang Mu

    This study evaluated the effect of temperature on methane production by CO2 reduction during microbial electrosynthesis (MES) with a mixed-culture biocathode. Reactor performance, in terms of the amount and rate of methane production, current density, and coulombic efficiency, was compared at different temperatures. The microbial properties of the biocathode at each temperature were also analyzed by 16S rRNA gene sequencing. The results showed that the optimum temperature for methane production from CO2 reduction in MES with a mixed-culture cathode was 50 °C, with the highest amount and rate of methane production of 2.06 ± 0.13 mmol and 0.094 ± 0.01 mmol h− 1, respectively. In the mixed-culture biocathode MES, the coulombic efficiency of methane formation was within a range of 19.15 ± 2.31% to 73.94 ± 2.18% due to by-product formation at the cathode, including volatile fatty acids and hydrogen. Microbial analysis demonstrated that temperature had an impact on the diversity of microbial communities in the biofilm that formed on the MES cathode. Specifically, the hydrogenotrophic methanogen Methanobacterium became the predominant archaea for methane production from CO2 reduction, while the abundance of the aceticlastic methanogen Methanosaeta decreased with increased temperature.

  • Peptide nucleic acid as a selective recognition element for electrochemical determination of Hg2 +
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-12
    Agnieszka Bala, Łukasz Górski

    A novel electrochemical PNA-based biosensor for the determination of Hg2 + is described. The receptor layer, containing single strands of polythymine PNA (peptide nucleic acid), was formed at the surface of gold electrode. Due to the presence of thymine bases and peptide bonds, an interaction between Hg2 + ion and receptor layer occurs. The influence of chain modification – PNA vs. DNA – and type of redox marker – anionic AQMS-Na (sodium salt of anthraquinone-2-sulfonic acid) and FeII/III (potassium ferri/ferrocyanide) or cationic MB (methylene blue) and RuHex (hexaammineruthenium(III) chloride) – were studied. Proposed PNA-based biosensor with anionic AQMS-Na as a redox marker demonstrated significantly better analytical parameters, as compared to results obtained for other tested redox markers (for measurements at pH 6.0). The linear response towards Hg2 + was in the range from 5 to 500 nmol·L− 1 with the detection limit of 4.5 nmol·L− 1. The developed sensor distinguishes itself with high selectivity towards Hg2 +, even for solutions containing several interfering cations. Interactions between Hg2 + and PNA receptor layer were studied using square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS).

  • Effects of mould on electrochemical migration behaviour of immersion silver finished printed circuit board
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-14
    Pan Yi, Kui Xiao, Chaofang Dong, Shiwen Zou, Xiaogang Li

    The role played by mould in the electrochemical migration (ECM) behaviour of an immersion silver finished printed circuit board (PCB-ImAg) under a direct current (DC) bias was investigated. An interesting phenomenon is found whereby mould, especially Aspergillus niger, can preferentially grow well on PCB-ImAg under electrical bias and then bridge integrated circuits and form a migration path. The cooperation of the mould and DC bias aggravates the ECM process occurring on PCB-ImAg. When the bias voltage is below 15 V, ECM almost does not occur for Ag coating. Mechanisms that explain the ECM processes of PCB-ImAg in the presence of mould and DC bias are proposed.

  • Conductive properties of methanogenic biofilms
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-19
    Cheng Li, Keaton Larson Lesnik, Hong Liu

    Extracellular electron transfer between syntrophic partners needs to be efficiently maintained in methanogenic environments. Direct extracellular electron transfer via electrical current is an alternative to indirect hydrogen transfer but requires construction of conductive extracellular structures. Conductive mechanisms and relationship between conductivity and the community composition in mixed-species methanogenic biofilms are not well understood. The present study investigated conductive behaviors of methanogenic biofilms and examined the correlation between biofilm conductivity and community composition between different anaerobic biofilms enriched from the same inoculum. Highest conductivity observed in methanogenic biofilms was 71.8 ± 4.0 μS/cm. Peak-manner response of conductivity upon changes over a range of electrochemical potentials suggests that electron transfer in methanogenic biofilms occurs through redox driven super-exchange. The strong correlation observed between biofilm conductivity and Geobacter spp. in the metabolically diverse anaerobic communities suggests that the efficiency of DEET may provide pressure for microbial communities to select for species that can produce electrical conduits.

  • Voltammetric behavior of Mammeisin (MA) at a glassy carbon electrode and its interaction with Bovine Serum Albumin (BSA)
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-07
    Jules-Blaise Mabou Leuna, Sergeot Kungo Sop, Suzanne Makota, Evangeline Njanja, Thiery Christophe Ebelle, Anatole Guy Azebaze, Emmanuel Ngameni, Achille Nassi

    The electrochemical oxidation of Mammeisin (MA) was studied in a solution containing acetone and 0.1 M phosphate buffer + 0.1 M KCl (pH = 5.3) at a glassy carbon electrode (GCE), using cyclic (CV) and square wave voltammetry (SWV). MA showed a quasi-reversible process, which is pH dependent and that involves the exchange of two electrons and two protons. The oxidation product was adsorbed by the electrode surface to form a film that blocks active sites over repetitive cyclic. Moreover, the interaction of MA and bovine serum albumin (BSA) was studied by CV and SWV at different pHs (5.4, 7.2, 9.5). As a result of the affinity binding with BSA, electrochemically inactive complex was formed. In addition, the oxidation potential of MA in the presence of BSA depends on the pH. The diffusion coefficients of both free and bound MA were estimated from the cyclic voltammetry data using the method developed by Randles-Sevich (Df = 9.85 × 10− 5 cm2 s− 1 and Db = 1.27 × 10− 9 cm2 s− 1) and the binding constant of MA-BSA complex, K = 3.47 × 102 L mol− 1, was obtained.

  • Modulating proposed electron transfer pathways in P450BM3 led to improved activity and coupling efficiency
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-18
    Dominique Darimont, Martin J. Weissenborn, Bernd A. Nebel, Bernhard Hauer
  • Electrochemistry and electron paramagnetic resonance spectroscopy of cytochrome c and its heme-disrupted analogs
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-09-21
    David Novak, Milos Mojovic, Aleksandra Pavicevic, Martina Zatloukalova, Lenka Hernychova, Martin Bartosik, Jan Vacek
  • Pyroelectricity as a possible mechanism for cell membrane permeabilization
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-19
    Tomás García-Sánchez, Adeline Muscat, Isabelle Leray, Lluis M. Mir

    The effects of pyroelectricity on cell membrane permeability had never been explored. Pyroelectricity consists in the generation of an electric field in the surface of some materials when a change in temperature is produced. In the present study, tourmaline microparticles, which are known to display pyroelectrical properties, were subjected to different changes in temperature upon exposure to cells in order to induce an electric field at their surface. Then, the changes in the permeability of the cell membrane to a cytotoxic agent (bleomycin) were assessed by a cloning efficacy test. An increase in the permeability of the cell membrane was only detected when tourmaline was subjected to a change in temperature. This suggests that the apparition of an induced pyroelectrical electric field on the material could actually be involved in the observed enhancement of the cell membrane permeability as a result of cell electropermeabilization.

  • Deciphering the electric code of Geobacter sulfurreducens in cocultures with Pseudomonas aeruginosa via SWATH-MS proteomics
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-03
    Lucie Semenec, Andrew E. Laloo, Benjamin L. Schulz, Ismael A. Vergara, Philip L. Bond, Ashley E. Franks

    Interspecies electron transfer (IET) occurs in many microbial communities, enabling extracellular electron exchange for syntrophic utilization of mixed resources. Various mechanisms of IET have been characterized including direct IET (DIET) and hydrogen IET (HIT) but their evolution throughout syntrophic adaptation has not been investigated through an omics approach. A syntrophic coculture of Geobacter sulfurreducens and Pseudomonas aeruginosa was established and evolved in restricted medium. The medium required cooperative metabolism due to preferential utilization of formate and fumarate by P. aeruginosa and G. sulfurreducens respectively. Pure cultures did not yield significant growth while substantial growth was observed in cocultures. The syntrophy was not reliant on phenazine, since Δphz mutant strain cocultures grew, however appeared to rely on cytochromes as evidenced from the stunted growth G. sulfurreducens ΔomcZ and ΔomcS mutant cocultures. SWATH (sequential window acquisition of all theoretical spectra) MS (mass spectrometry) proteomic analysis of initial cocultures revealed upregulation in DIET-associated cytochromes, whereas adapted cocultures revealed upregulation in HybA, a G. sulfurreducens uptake hydrogenase critical to HIT. This suggests DIET plays a critical role in the establishment of syntrophy between G. sulfurreducens and P. aeruginosa but is later consolidated with HIT as the cocultures adapt. This is the first instance to show a temporal distribution of DIET and HIT within the same coculture.

  • Flavins mediate extracellular electron transfer in Gram-positive Bacillus megaterium strain LLD-1
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-10-16
    Le-Xing You, Li-Dan Liu, Yong Xiao, You-Fen Dai, Bi-Lian Chen, Yan-Xia Jiang, Feng Zhao
  • Polyvinylidene fluoride effects on the electrocatalytic properties of air cathodes in microbial fuel cells
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-12-13
    Guowen Wang, Xiaoning Duan, Dong Wang, Xiaoli Dong, Xiufang Zhang
  • 更新日期:2017-12-14
  • 更新日期:2017-12-08
  • Aspects on mediated glucose oxidation at a supported cubic phase
    Bioelectrochemistry (IF 3.346) Pub Date : 2017-06-22
    Mahdi Shahmohammadi Aghbolagh, Mohammad Yaser Khani Meynaq, Kenichi Shimizu, Britta Lindholm-Sethson

    A supported liquid crystalline cubic phase housing glucose oxidase on an electrode surface has been suggested as bio-anode in a biofuel. The purpose of this investigation is to clarify some aspect on the mediated enzymatic oxidation of glucose in such a bio-anode where the mediator ferrocene-carboxylic acid and glucose were dissolved in the solution. The enzyme glucose oxidase was housed in the water channels of the mono-olein cubic phase. The system was investigated with cyclic voltammetry at different scan rates and the temperature was varied between 15 °C and 30 °C. The diffusion coefficient of the mediator and also the film resistance was estimated showing a large decrease in the mass-transport properties as the temperature was decreased. The current from mediated oxidation of glucose at the electrode surface increased with decreasing film thickness. The transport of the mediator in the cubic phase was the rate-limiting step in the overall reaction, where the oxidation of glucose took place at the outer surface of the cubic phase.

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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