Mehdi Tahernia, M. Mohammadifar, S. Feng et al.

2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS) • 2020

Electroactive bacteria with in-situ biogenic palladium nanoparticles increased power density of a microbial fuel cell (MFC) by 75%. The palladium nanoparticles were biosynthesized through bioelectrochemical reduction by the bacteria and remained bound to the cell membrane, facilitating bacterial extracellular electron transfer at the cell-electrode interface. This work revolutionizes knowledge of how bacteria biosynthesize metallic nanoparticles during microbial metabolism and introduces a novel bottom-up approach to fabricate a microbial electrochemical device for renewable energy production in a more eco-friendly and cost-effective way.

Yucui Shi, G. Tang, Yan-Ying Ye et al.

IOP Conference Series: Earth and Environmental Science • 2021

Constructed wetland-microbial fuel cell coupling system is a new type of bioelectrochemical system that couples constructed wetland and microbial fuel cell. The system plays an important role in biological power generation and sewage purification. The principle is that the bottom of the constructed wetland bed (low ORP) serves as the anode of the microbial fuel cell. The organic matter in the water is degraded under the action of the electricity-producing microorganisms and released during the degradation process. The electrons are transferred along the external circuit to the biocathode on the surface of the bed (higher ORP) to complete the redox reaction. This article summarizes the research progress of the microbial fuel cell-constructed wetland coupling system from two aspects: system structure and factors affecting system operation. The system structure includes electrode materials, substrates, wetland plants and microorganisms. The influencing factors include HRT, DO, organic matter concentration and wastewater composition, electrode structure. Finally, the problems and research directions of the microbial fuel cell-constructed wetland coupling system are summarized, and the research potential of the system is prospected.

R. Apak, S. D. Çekiç, A. Üzer et al.

Sensors • 2018

Since an unbalanced excess of reactive oxygen/nitrogen species (ROS/RNS) causes various diseases, determination of antioxidants that can counter oxidative stress is important in food and biological analyses. Optical/electrochemical nanosensors have attracted attention in antioxidant activity (AOA) assessment because of their increased sensitivity and selectivity. Optical sensors offer advantages such as low cost, flexibility, remote control, speed, miniaturization and on-site/in situ analysis. Electrochemical sensors using noble metal nanoparticles on modified electrodes better catalyze bioelectrochemical reactions. We summarize the design principles of colorimetric sensors and nanoprobes for food antioxidants (including electron-transfer based and ROS/RNS scavenging assays) and important milestones contributed by our laboratory. We present novel sensors and nanoprobes together with their mechanisms and analytical performances. Our colorimetric sensors for AOA measurement made use of cupric-neocuproine and ferric-phenanthroline complexes immobilized on a Nafion membrane. We recently designed an optical oxidant/antioxidant sensor using N,N-dimethyl-p-phenylene diamine (DMPD) as probe, from which ROS produced colored DMPD-quinone cationic radicals electrostatically retained on a Nafion membrane. The attenuation of initial color by antioxidants enabled indirect AOA estimation. The surface plasmon resonance absorption of silver nanoparticles as a result of enlargement of citrate-reduced seed particles by antioxidant addition enabled a linear response of AOA. We determined biothiols with Ellman reagent−derivatized gold nanoparticles.

Siham Elmazouzi, Youssef Naimi, I. Zerdani

2022 11th International Conference on Renewable Energy Research and Application (ICRERA) • 2022

A microbial fuel cell (MFC) is a bioelectrochemical system that spontaneously converts biomass into electricity thanks to the metabolism of bacteria present in the environment. it transforms the chemical energy contained in organic matter into electricity. The objective of this study is to develop a bio-anode by enhancing the environment for electroactive biofilm development and using a 1 cm2 carbon fiber electrode. Le biofilm electro-active was developed using nutrient broth infused with bacteria, with a potential (-0,150 V/ESH). Beginning on day nine, electrochemical activity is noted, reaching a peak of 90 mA on day thirty. Even after applying a potential for several days, control experiments in sealed environments show no current.

P. Bollella, L. Gorton, R. Antiochia

Sensors • 2018

Dehydrogenase based bioelectrocatalysis has been increasingly exploited in recent years in order to develop new bioelectrochemical devices, such as biosensors and biofuel cells, with improved performances. In some cases, dehydrogeases are able to directly exchange electrons with an appropriately designed electrode surface, without the need for an added redox mediator, allowing bioelectrocatalysis based on a direct electron transfer process. In this review we briefly describe the electron transfer mechanism of dehydrogenase enzymes and some of the characteristics required for bioelectrocatalysis reactions via a direct electron transfer mechanism. Special attention is given to cellobiose dehydrogenase and fructose dehydrogenase, which showed efficient direct electron transfer reactions. An overview of the most recent biosensors and biofuel cells based on the two dehydrogenases will be presented. The various strategies to prepare modified electrodes in order to improve the electron transfer properties of the device will be carefully investigated and all analytical parameters will be presented, discussed and compared.

Hanie Soleimani, M. Rahimnejad, M. Mashkour

2023 8th International Conference on Technology and Energy Management (ICTEM) • 2023

Sediment microbial fuel cells (SMFCs) are Bioelectrochemical systems that have the ability to produce bioelectricity. However, the amount of low organic matter sediment limits their output power. Furthermore, another factor, which causes low Power generation capacity in Sediment microbial fuel cells, is the low conductivity of the catholyte. In the current paper, we employed spirulina algae powder to increase the organic load of the sediment. We also investigated the effect of catholyte conductivity on SMFC performance by using three different periods, including river water with a conductivity of 2mS, tap water with a conductivity of 243mS, and synthetic water with a conductivity of 2mS. The results of the power curves showed that the highest power density was produced by SMFC-1 (117.78 mW/m2), which improved by 77% compared to SMFC-01. In addition, according to the polarization curves of SMFC-1 and SMFC-01, the maximum current density also increased with increasing conductivity, so the highest current density was produced by SMFC-1 in the third phase. Also, CV and EIS analyses showed an increase in the current density rate and a fall in internal resistance. These findings showed that the use of spirulina algae powder as an additional substrate and increasing the conductivity of the catholyte can be considered as an effective approach to increase the power of SMFCs.

Eivydas Andriukonis, Marius Butkevicius, Povilas Šimonis et al.

Sensors • 2023

Currently, Ag/AgCl-based reference electrodes are used in most electrochemical biosensors and other bioelectrochemical devices. However, standard reference electrodes are rather large and do not always fit within electrochemical cells designed for the determination of analytes in low-volume aliquots. Therefore, various designs and improvements in reference electrodes are critical for the future development of electrochemical biosensors and other bioelectrochemical devices. In this study, we explain a procedure to apply common laboratory polyacrylamide hydrogel in a semipermeable junction membrane between the Ag/AgCl reference electrode and the electrochemical cell. During this research, we have created disposable, easily scalable, and reproducible membranes suitable for the design of reference electrodes. Thus, we came up with castable semipermeable membranes for reference electrodes. Performed experiments highlighted the most suitable gel formation conditions to achieve optimal porosity. Here, Cl− ion diffusion through the designed polymeric junctions was evaluated. The designed reference electrode was also tested in a three-electrode flow system. The results show that home-built electrodes can compete with commercial products due to low reference electrode potential deviation (~3 mV), long shelf-life (up to six months), good stability, low cost, and disposability. The results show a high response rate, which makes in-house formed polyacrylamide gel junctions good membrane alternatives in the design of reference electrodes, especially for these applications where high-intensity dyes or toxic compounds are used and therefore disposable electrodes are required.

Vafa Ahmadi, Aryan Bhusal, G. S. Arachchige et al.

Linköping Electronic Conference Proceedings • 2025

: Microbial biofilm matrices offer numerous benefits in bioprocessing and are crucial in various industrial and remediation processes. They facilitate electron exchange from solid surfaces when they interact with the environment. Emerging technologies such as biofilm-containing trickle bed reactors (TBR) and bioelectrochemical systems (BESs) for carbon dioxide (CO 2 ) utilization, mostly rely on microbial biofilm matrices. Metabolic modeling of biofilm-based reactors enables detailed analysis of CO 2 reduction within microorganisms, enhancing reactor efficiency. This study employed simulation models to analyze biomethane synthesis within TBR and BES systems. AQUASIM simulation tool was used for conducting the simulation. Parameters such as non-stoichiometric and stoichiometric ratios of substrates, hydraulic retention time (HRT), biofilm surface area, and applied voltage in BES were varied to evaluate methane (CH 4 ) production and microbial biomass growth in TBR and BES. Results demonstrated that 1 day HRT resulted in methanation process failure due to biomass development problem in both TBR and BES. The substrate ratio 1:4 of CO 2 to H 2 increased CH 4 production in the investigated reactors. In BES, in-situ CO 2 and proton (H + ) generation from oxidation reactions can increase CH 4 production. Whereas in TBR, external H 2 (hydrogen) should be supplied to consume higher amount of CO 2 . The lag phase in TBR was shorter than that in BES because of the greater surface area in TBR. In BES, higher voltage increased the current generation because of development of more biomass on the cathode. The simulation underlines the influence of different variables on biofilm-based reactors, offering critical insights for experimental process design.

Michael Holzinger

2023 IEEE Nanotechnology Materials and Devices Conference (NMDC) • 2023

Due to the increasing need to monitor health and environment in real time and to energize small electronic devices, new materials are under extensive investigations. Between others, carbon nanotubes (CNTs) are promising alternatives as building blocks in bioelectrochemical devices due to their unique electrical, mechanical properties, and their high specific surface. Furthermore, their ease and well-established organic functionalization brings new properties to nanostructured electrodes such as specific docking sites for biomolecules. Moreover, CNT films exhibit a high electroactive surface area due to the natural formation of highly porous three-dimensional networks, suitable for the anchoring of a high amount of bioreceptor units, thus leading to improved sensitivities. With some simple functionalization techniques, CNTs can acts as almost perfect support for enzyme wiring and is still the privileged material in the field of enzymatic biofuel cells. The most appropriate functionalization techniques for CNTs are summarized leading to enhance the performances of biosensors and biofuel cells.

Michael Krumpelt, Theodore R. Krause, John P. Kopasz

1st International Fuel Cell Science, Engineering and Technology Conference • 2003

Fuel cells may in the future compete with heat engines in automobiles and motor generators and with batteries in portable electronics. Hydrogen, either in compressed, cryogenic, or chemically stored form is a good fuel if the storage density can be improved. Alternatively, the hydrogen could be obtained by converting gasoline, alcohols or other liquid hydrocarbons into a hydrogen-rich gas in a fuel processor that is a component of the fuel cell system. Such processors will have to be small, light, and inexpensive, and will have to have rapid ramp-up and ramp-down capabilities to follow the power demands of the applications. Traditional steam reforming technology does not meet these requirements, but newly developed catalytic auto-thermal reformers do. The principles of operation and the status of the technology are discussed.

I. Samanta, R. K. Shah, A. Wagner

2nd International Conference on Fuel Cell Science, Engineering and Technology • 2004

At its essence, a fuel cell combines hydrogen and oxygen to form electricity, heat, and water. The source of this hydrogen may be from natural gas, coal, gasoline, diesel, alcohols, or natural decomposition products. Pure hydrogen is the ideal fuel, but it needs to be obtained by processing fossil fuels (natural gas, gasoline, diesel, oil, coal, etc.), biofuels (e.g., landfill gas, anaerobic digester gas, etc.), or chemical intermediates, or must be produced via renewable energy sources through electrolysis of water. Currently pure hydrogen is produced cryogenically at both a great energy and fiscal expense. In this paper, we cover all important fuel reforming processes for generating hydrogen for fuel cells and then discuss the associated reformers. The common techniques utilized for external fuel reforming processes are steam reforming, partial oxidation and autothermal reforming. For high temperature fuel cells, direct and indirect internal reforming techniques are used and will be discussed. The methods for reforming of chemical intermediates (alcohol and ammonia), reforming of bio-fuels and aviation fuels are also discussed in this paper. For low temperature fuel cells such as PEM, carbon monoxide is a poison that adversely affects fuel cell performance. The CO content must be reduced to below 100 ppm. This is accomplished by use of the water-gas shift reaction, preferential oxidation, methanation, or may be accomplished by membrane separation techniques. Special emphasis in this paper will be the challenges and opportunities in fuel processing for fuel cells.

Kas Hemmes

2nd International Conference on Fuel Cell Science, Engineering and Technology • 2004

In spite of the fact that the development of fuel cells is a scientific and technological process, the process, itself seems to be largely determined by the human factor. By a number of examples it will be shown that this development and the creative process necessary for its progress is sometimes hindered by strong beliefs and frequently repeated statements that within themselves hold some truth but do not represent the whole truth. They can be regarded as ‘fuel cell dogmas’. Often implicit assumptions or particular boundary conditions lie behind the dogma. These assumptions or conditions may be altered in the course of the developments or for specific applications. Sometimes the dogma is essentially a rumor that is conveniently accepted by newcomers in the field. An example of the latter is the ban on the use of LiNa carbonate electrolyte in a MCFC instead of LiK because of its supposed higher corrosiveness. Nowadays LiNa is accepted as the new standard electrolyte in a MCFC. The most famous dogma is that fuel cells are more efficient than heat engines because they are not limited by the Carnot efficiency. Yet it is not always true, not even in the reversible limit. For a long time polymer fuel cells were considered to be inherently too expensive because of the membrane and the Pt catalyst. They were considered only suitable for niche markets such as space applications. As we know now General Motors believes differently. Other dogmas are: - Fuel cells have a higher efficiency than heat engines. - A fuel cell converts Hydrogen into power and heat. - Nernst loss is always proportional to utilization and inevitable. - To be economically feasible the fuel gas utilization should be as high as possible. - To be economically feasible the fuel cell should be operated at the highest possible power density. - A fuel cell always has two inlets and two outlets. - In order to use solid fuels in a fuel cell they must be gasified first. - Only low temperature fuel cells are suitable for automotive applications. These and other dogmas will be critically analyzed in terms of the underlying assumptions and boundary conditions. New options that are revealed by breaking through the dogmas are briefly sketched.

Arka Chatterjee, Avijit Das, Kundan Saha et al.

Advanced Sensor Research • 2023

Abstract Piezoelectric self‐powered sensors are promising platforms for wearable portable devices. Poly(vinylidene fluoride) (PVDF) and its copolymer derivatives are extensively explored as a soft piezoelectric material owing to their high piezoelectric coefficient, chemical thermal stability, biocompatibility, lightweight, and excellent flexibility. It is proved that the dominance of the electroactive (EA) β‐phase crystals versus the non‐electroactive α‐phase crystals is one of the key parameters to obtaining high piezoelectric performance of PVDF. Conventional methods, such as mechanical stretching, electrical poling, and high‐temperature annealing, are investigated to enhance the fraction of the β‐phase. Recently, embedding nanoscale fillers in the PVDF matrix has been investigated to further increase the β‐phase fraction and achieved considerable advances. The introduction of nanofillers is also advantageous in terms of improving the electrical conductivity and dielectric properties of PVDF, which are not readily obtained through conventional methods. This review introduces the principles of EA phase transformation in the presence of nanofillers and summarizes recent advances achieved by introducing various fillers, such as perovskites, oxide semiconductors, and 2D chalcogenides. The potential sensor applications of the PVDF nanocomposites responding to temperature, light, acoustic, and mechanical stimuli are reviewed. This review ends with the outlook of this new approach.

Ananta Ghimire, Omkar Zore, Vindya Thilakarathne et al.

Sensors • 2015

In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, MW 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17–20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at −0.279 and −0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications.

Mathias Fessler, Qingxian Su, Marlene Mark Jensen et al.

Frontiers of Environmental Science & Engineering • 2024

Abstract Magnetotactic bacteria reside in sediments and stratified water columns. They are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field lines. Here, we show that two magnetotactic species, Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1, are electroactive. Both M. magneticum and M. gryphiswaldense were able to generate current in microbial fuel cells with maximum power densities of 27 and 11 µW/m 2 , respectively. In the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite (Fe 2 O 3 ). In addition, M. magneticum could reduce poorly crystalline iron oxide (FeOOH). Our study adds M. magneticum and M. gryphiswaldense to the growing list of known electroactive bacteria, and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

Naser Mohammadi, Juan Carlos Abrego-Martinez, Mohamed Mohamedi

Molecules • 2022

We report here the synthesis of binderless and template-less three-dimensional (3D) pinecone-shaped Pt/TiO2/Ti mesh structure. The TiO2 hydrothermally synthesized onto Ti mesh is composed of a mixture of flower-like nanorods and vertically aligned bar-shaped structures, whereas Pt film grown by pulsed laser deposition displays a smooth surface. XRD analyses reveal an average crystallite size of 41.4 nm and 68.5 nm of the TiO2 nanorods and Pt, respectively. In H2SO4 solution, the platinum oxide formation at the Pt/TiO2/Ti mesh electrode is 180 mV more negative than that at the Pt/Ti mesh electrode, indicating that TiO2 provides oxygeneous species at lower potentials, which will facilitate the removal of CO-like intermediates and accelerate an ethanol oxidation reaction (EOR). Indeed, the Pt/TiO2/Ti mesh catalyst exhibits current activity of 1.19 mA towards an EOR at a remarkably superior rate of 4.4 times that of the Pt/Ti mesh electrode (0.27 mA). Moreover, the presence of TiO2 as a support to Pt delivers a steady-state current of 2.1 mA, with an increment in durability of 6.6 times compared to Pt/Ti mesh (0.32 mA). Pt is chosen here as a benchmark catalyst and we believe that with catalysts that perform better than Pt, such 3D pinecone structures can be useful for a variety of catalytic or photoelectrochemical reactions.

Emilie Lyautey, Amandine Cournet, Soizic Morin et al.

Applied and Environmental Microbiology • 2011

ABSTRACT Electroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyll a content, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from −0.36 to −0.76 V/SCE, and peak amplitudes ranging from −9.5 to −19.4 μA. These isolates were diversified phylogenetically ( Actinobacteria , Firmicutes , Bacteroidetes , and Alpha -, Beta -, and Gammaproteobacteria ) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowing in situ phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions.

JinWon Lee, Sungwook Chung, Seok Kim

Journal of Nanoscience and Nanotechnology • 2020

We synthesize the Pt-carbon composite which is composed of unzipped multi-walled carbon nanotube (UMWCNT) and graphene oxide (GO). Graphite and multi-walled carbon nanotube (MWCNT) are oxidized by same method that modified Hummer’s method for making GO and UMWCNT. 3D structure could be prepared by polyol process which contains simultaneously reduction GO and UMWCNT. The electrochemical and morphological property of Pt-carbon composites was investigated by Fourier Transform Infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), and Cyclic Voltammetry (CV). These results show that Pt-rGO/UMWCNT (8:2) hybrids exhibited high catalytic activity due to the enhanced surface area of carbon supports.

Yaovi Holade, Claudia Morais, Karine Servat et al.

Phys. Chem. Chem. Phys. • 2014

We report a convenient and straightforward thermal pre-treatment to improve the physicochemical properties of carbon-based substrates to boost the catalytic activity of platinum nanoparticles.

Gertrude Fomo, Tesfaye Waryo, Christopher Sunday et al.

Sensors • 2015

The work being reported is the first electrochemical sensor for tetrodotoxin (TTX). It was developed on a glassy carbon electrodes (C) that was modified with poly(4-styrenesolfonic acid)-doped polyaniline film (PANI/PSSA). An amine-end functionalized TTX-binding aptamer, 5′-NH2-AAAAATTTCACACGGGTGCCTCGGCTGTCC-3′ (NH2-Apt), was grafted via covalent glutaraldehyde (glu) cross-linking. The resulting aptasensor (C//PANI+/PSSA-glu-NH2-Apt) was interrogated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in sodium acetate buffer (NaOAc, pH 4.8) before and after 30 min incubation in standard TTX solutions. Both CV and EIS results confirmed that the binding of the analyte to the immobilized aptamer modulated the electrochemical properties of the sensor: particularly the charge transfer resistance (Rct) of the PANI+/PSSA film, which served as a signal reporter. Based on the Rct calibration curve of the TTX aptasensor, the values of the dynamic linear range (DLR), sensitivity and limit of detection (LOD) of the sensor were determined to be 0.23–1.07 ng·mL−1 TTX, 134.88 ± 11.42 Ω·ng·mL−1 and 0.199 ng·mL−1, respectively. Further studies are being planned to improve the DLR as well as to evaluate selectivity and matrix effects in real samples.

Long Hoang Bao Nguyen, Jean‐Sébastien Filhol

Advanced Energy Materials • 2023

Abstract The electrochemical activity of solvated Ca 2+ in glyme‐based electrolytes is investigated using grand canonical density functional theory approach and Fukui functions. The obtained results reveal that the length of glyme molecules has little effect on the reduction potentials, but has significant impacts on the effective electron transfer process. In short chain glymes, the transferred electron is located on a Ca 2+ center and the organic part of the solvation sphere, leading to a direct Ca 2+ reduction and a partial degradation of the glyme molecules. As the glyme's length increases, the reduction process turns into the formation of solvated electrons rather than Ca 2+ reduction, unless a partial desolvation occurs. Consequently, an effective Ca 2+ reduction in long chain glyme‐based electrolytes is controlled by a (partial) desolvation of the solvation sphere. These results can be used as guiding information to design new electrolytes having the Ca 2+ reduction potential in an accessible voltage range together with an effective Ca 2+ reduction process. The methodology developed in this study can be universally applied to investigate the thermodynamic and kinetic properties of other battery systems using metal anodes, which might lead to a paradigm shift in the design of prospective electrolytes for future battery technologies.

Erin M. Gaffney, Ashwini Dantanarayana, Olja Simoska et al.

Journal of The Electrochemical Society • 2022

Microbial electrochemical technologies are becoming an interest for the electrochemical community due to their possible applications in wastewater treatment, biosensing, biosynthesis, and bioenergy. Fundamental to these technologies is the use of electroactive microorganisms as bioelectrocatalysts. Recent studies have aimed to elucidate electron transfer strategies of electroactive microorganisms, with a keen interest in extremophilic bacteria due to their enhanced survivability in variable and extreme conditions, making them a better candidate for use in microbial electrochemical technologies. Recently, the species Salinivibrio sp. EAGSL was isolated from the Great Salt Lake, Utah, for its anodic respiration capabilities. In this work, electroanalytical techniques offer the primary information regarding the electroactive mechanisms of S alinivibrio sp. EAGSL. Additionally, measuring the current production over time shows electricity production over 3 days. Fundamental insights from the recently determined genome sequence offer possible explanations and mechanisms of this behavior and other metabolisms of interest for microbial electrochemistry. By elucidating the extracellular electron transfer pathways of Salinivibrio sp . EAGSL, the pairing of electroanalytical and genomic methods can provide a framework of study for other novel electroactive species.

Hyun-Woo Shim, Ah-Hyeon Lim, Gwang-Hee Lee et al.

Nanoscale Research Letters • 2012

Abstract Carbon-coated ZnWO 4 [C-ZW] nanorods with a one-dimensional core/shell structure were synthesised using hydrothermally prepared ZnWO 4 and malic acid as precursors. The effects of the carbon coating on the ZnWO 4 nanorods are investigated by thermogravimetry, high-resolution transmission electron microscopy, and Raman spectroscopy. The coating layer was found to be in uniform thickness of approximately 3 nm. Moreover, the D and G bands of carbon were clearly observed at around 1,350 and 1,600 cm -1 , respectively, in the Raman spectra of the C-ZW nanorods. Furthermore, lithium electroactivities of the C-ZW nanorods were evaluated using cyclic voltammetry and galvanostatic cycling. In particular, the formed C-ZW nanorods exhibited excellent electrochemical performances, with rate capabilities better than those of bare ZnWO 4 nanorods at different current rates, as well as a coulombic efficiency exceeding 98%. The specific capacity of the C-ZW nanorods maintained itself at approximately 170 mAh g -1 , even at a high current rate of 3 C, which is much higher than pure ZnWO 4 nanorods.

Ludek Havran, Sabina Billová, Emil Palecek

Electroanalysis • 2004

Abstract Avidin and streptavidin were studied by phase‐sensitive AC and cyclic voltammetry as well as by constant current chronopotentiometry at mercury (in alkaline media) and carbon electrodes (in acid medium). In contrast to the generally accepted belief that these proteins are electroinactive, we observed various electrochemical responses at these electrodes. Both proteins produced peaks due to oxidation of tyrosine and tryptophan residues at carbon electrodes and a catalytic peak H at a hanging mercury drop electrode. At the latter electrode avidin produced phase‐in AC voltammetric and cyclic voltammetric peaks close to −0.6 V (peak S) which were assigned to Hg‐S interactions, involving cystine/cysteine residues. In cobalt containing solution avidin produced a characteristic catalytic double wave requiring presence of cystine/cysteine residues in the protein molecule. Streptavidin, which does not contain these residues, yielded neither the catalytic double wave nor peak S. All the above avidin signals responded to biotin binding; peak S increased (up to 4 biotin molecules bound) while other avidin signals decreased as a result of biotin binding. A tentative scheme of interfacial behavior of avidin and avidin‐biotin complex, depending on the electrode charge, was suggested.

Allison M. Speers, Gemma Reguera

Applied and Environmental Microbiology • 2012

ABSTRACT Geobacter bacteria efficiently oxidize acetate into electricity in bioelectrochemical systems, yet the range of fermentation products that support the growth of anode biofilms and electricity production has not been thoroughly investigated. Here, we show that Geobacter sulfurreducens oxidized formate and lactate with electrodes and Fe(III) as terminal electron acceptors, though with reduced efficiency compared to acetate. The structure of the formate and lactate biofilms increased in roughness, and the substratum coverage decreased, to alleviate the metabolic constraints derived from the assimilation of carbon from the substrates. Low levels of acetate promoted formate carbon assimilation and biofilm growth and increased the system's performance to levels comparable to those with acetate only. Lactate carbon assimilation also limited biofilm growth and led to the partial oxidization of lactate to acetate. However, lactate was fully oxidized in the presence of fumarate, which redirected carbon fluxes into the tricarboxylic acid (TCA) cycle, and by acetate-grown biofilms. These results expand the known ranges of electron donors for Geobacter -driven fuel cells and identify microbial constraints that can be targeted to develop better-performing strains and increase the performance of bioelectrochemical systems.

K. Sudhakara Prasad, Charuksha Walgama, Sadagopan Krishnan

RSC Advances • 2015

An exceptionally large electroactively connected microperoxidase-11 (MP-11) with strong affinity for organic peroxide and offering a high electrocatalytic reduction current density of 7.5 mA cm −2 is achieved for the first time.

Aiping Zhu, Hongsheng Wang, Chaoqun Zhang

Polymer Composites • 2018

In this work, the novel nanofiber composites of graphene/poly(aniline‐co‐5‐aminosalicylic acid) were prepared by in situ reduction of graphene oxide (GO) followed by in situ copolymerization of aniline and 5‐aminosalicylic acid under acid conditions. The morphology, composition, microstructure, and properties of these composites can be tailored by π‐π stacking manipulation through controlling the mass ratios of GO to copolymerization monomers. The incorporation of rGO greatly improves the electrical conductivity of nanocomposites and electrochemical activity not only at acidic, but also at neutral solution, strikingly different from the behavior of pristine PANI which become electrochemically inactive from pH ≥ 4. The composite with GO/poly(aniline‐co‐5‐aminosalicylic acid) mass ratio at 8 shows excellent electrical conductivity and redox reactivity due to the synergistic effect of graphene and poly(aniline‐co‐5‐aminosalicylic acid) copolymer. POLYM. COMPOS., 39:2915–2921, 2018. © 2017 Society of Plastics Engineers

Audacity Maringa, Tebello Nyokong

Journal of Porphyrins and Phthalocyanines • 2014

We report on the electrodeposition of gold nanoparticles ( AuNPs ) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine ( NiTSPc ) film by electropolymerization (poly- NiTSPc -GCE) to form Poly- NiTSPc / AuNPs -GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔE p ) of ferricyanide from 126 mV on poly- NiTSPc to 110 mV on poly- NiTSPc / AuNPs . The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving E p = 0.78 V and the modified electrodes gave E p = 0.62 V or 0.61 V. Poly- NiTSPc / AuNPs -GCE had higher currents compared to poly- NiTSPc -GCE. This indicates the enhancement effect caused by the AuNPs . Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly- NiTSPc / AuNPs -GCE was a better electrocatalyst than poly- NiTSPc -GCE or AuNPs -GCE.

C. Garcia-Mogollon, C. Avignone-Rossa, A. Arrieta Almario et al.

RASAYAN Journal of Chemistry • 2023

The capability of certain microbial strains to uptake electrons and fix CO2 can be exploited to capture greenhouse gas and convert it into products of interest through a process called microbial bioelectrosynthesis. This study evaluated the capability of C. saccharoperbutylacetonicum N1-4 to utilize bicarbonate for growth, by both supplying electrons in a single-cell reactor and using a graphite-felt assembly as electrodes. The medium was supplemented with 4 g/L bicarbonate and 200 µM NADH. An open circuit experiment was carried out in a medium with bicarbonate and no complex nitrogen sources. The applied potential was -600 mVAg/AgCl. The impedance spectroscopy and cyclic voltammetry techniques were used to characterize and monitor the reduction and oxidation peaks. The conditions that promote the highest observed specific growth rate (0.87±0.18 h-1), were -600 mV, 4 g/L HCO3 -, and NADH. The growth rates of 0.57±0.01 h-1 were observed at 4 g/L HCO3 - without any potential input, and 0.51±0.10 h-1 at a potential of -600 mV in the presence of NADH. The results showed that an environment that provides exogenous electrons and an externally applied potential promotes the capability of C. saccharoperbutylacetonicum N1-4 to reduce CO2, as evidenced when biomass concentration and specific growth rate were increased.

Emil Paleček, Veronika Ostatná

Electroanalysis • 2007

Abstract Present proteomics and biomedicine require sensitive analytical methods for all proteins. Recent progress in electrochemical analysis of peptides and proteins based on their intrinsic electroactivity is reviewed. Tyrosine and/or tryptophan‐containing proteins are oxidizable at carbon electrodes. At mercury electrodes all peptides and proteins (about 13 peptides and >25 proteins were tested) produce chronopotentiometric peak H at nanomolar concentrations. This peak is sensitive to changes in protein structure. Microliter sample volumes are sufficient for the analysis. Electrochemical methods can be used in studies of nucleic acid‐protein interactions and can be applied in biomedicine. Examples of such applications in neurogenerative diseases and cancer are presented.

Yanyan Wang, Kalle Levon

Macromolecular Symposia • 2012

Abstract Polyaniline (PANI) films were polymerized on glass carbon (GC) electrodes with small molecular dopantshydrochloric, perchloric, sulfuric, methanesulfonic, benzenesulfonic, ρ‐ toluenesulfonic and large macromolecular size poly(4‐styrenesulfonic (PSS)), poly(vinylsulfonic), poly(acrylic), and poly(anilinesulfonic) acids.Theredox electroactiveswere studied in buffered solutions with the pH of 3, 5, 7, and 9. Results indicated that the properties PANI films were strongly dependent on the molecular size and polar characteristics of the dopants. With the polyelectrolytes, it was found that the PANI doped with PSS showed a good redox behavior, and maintained the inherent electro activity of PANI in the neutral and even in alkaline media.

Tetsuya Osaka, Toshiyuki Momma, Ken Nishimura

Chemistry Letters • 1992

Abstract Electroactivity of polypyrrole/polystyrenesulfonate composite film obtained from an aqueous solution was examined in various organic electrolytes. The composite film worked like electroinactive film in electrolyte using propylene carbonate or some solvents except in the case of DMF or DMSO electrolytes, however, the film changed from electroinactive to electroactive even in propylene carbonate and some organic electrolytes after an electrochemical potential application to the film while in DMF or DMSO electrolytes.

Mohammed Mouhib, Melania Reggente, Lin Li et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2021

Extracellular electron transfer (EET) engineering in Escherichia coli holds great potential for bioremediation, energy and electrosynthesis applications fueled by readily available organic substrates. Due to its vast metabolic capabilities and availability of synthetic biology tools to adapt strains to specific applications, E. coli is of advantage over native exoelectrogens, but limited in electron transfer rates. We enhanced EET in engineered strains through systematic expression of electron transfer pathways differing in cytochrome composition, localization and origin. While a hybrid pathway harboring components of an E. coli nitrate reductase and the Mtr complex from the exoelectrogen Shewanella oneidensis MR-1 enhanced EET, the highest efficiency was achieved by implementing the complete Mtr pathway from S. oneidensis MR1 in E. coli . We show periplasmic electron shuttling through overexpression of a small tetraheme cytochrome to be central to the electroactivity of this strain, leading to enhanced degradation of the pollutant methyl orange and significantly increased electrical current to graphite electrodes.

M. Ramírez‐Moreno, R. Berenguer, J. M. Ortiz et al.

Microbial Biotechnology • 2024

Abstract Expanded graphite (EG) electrodes gather several advantages for their utilization in microbial electrochemical technologies (MET). Unfortunately, the low microbial electroactivity makes them non‐practical for implementing them as electrodes. The objective of this work is to explore the enhancement of microbial electroactivity of expanded graphite (commercial PV15) through the generation of nanopores by CO 2 treatment. The changes in properties were thoroughly analysed by TG, XRD, Raman, XPS, gas adsorption, SEM and AFM, as well as microbial electroactivity in the presence of Geobacter sulfurreducens . Nanopores remarkably enhance the microbially derived electrical current (60‐fold increase). Given the inaccessibility of micron‐sized bacteria to these nanopores, it is suggested that the electric charge exchanged by electroactive microorganisms might be greatly affected by the capability of the electrode to compensate these charges through ion adsorption. The increased microbial current density produced on activated PV15 opens the possibility of using such materials as promising electrodes in MET.

E. Mylott, E. Kutschera, R. Widenhorn

American Journal of Physics • 2014

We present a novel laboratory activity on RC circuits aimed at introductory physics students in life-science majors. The activity teaches principles of RC circuits by connecting ac-circuit concepts to bioelectrical impedance analysis (BIA) using a custom-designed educational BIA device. The activity shows how a BIA device works and how current, voltage, and impedance measurements relate to bioelectrical characteristics of the human body. From this, useful observations can be made including body water, fat-free mass, and body fat percentage. The laboratory is engaging to pre-health and life-science students, as well as engineering students who are given the opportunity to observe electrical components and construction of a commonly used biomedical device. Electrical concepts investigated include alternating current, electrical potential, resistance, capacitance, impedance, frequency, phase shift, device design, and the use of such topics in biomedical analysis.

Weifeng Zhang, Gaocai Li, Bingjin Wang et al.

Advanced Functional Materials • 2022

Triboelectric nanogenerators (TENGs) are an efficient state‐of‐the‐art kinetic energy‐harvesting technology based on the combination of triboelectrification and electrostatic induction to generate electrical energy from ambient mechanical energy. Bioelectricity is a quintessential characteristic of living organisms and has a crucial role in physiological and medical sciences. Living cells are capable of generating electrical signals and responding to electrical stimulation, which are known to be key properties that regulate cellular behaviors and cell–microenvironment interactions. TENGs, with the advantages of miniaturization and efficiency, are notably exploited in efforts to provide self‐powered electrical stimulation to cells for functional modulation or fate determination, leading to a new methodology in biology and medical science. In this review, the progress, challenges, and future prospects of cellular bioelectrical stimulation with TENGs are focused. The regulation of cellular activity involved in functional modulation and fate determination stimulated by TENGs is highlighted. Furthermore, the application of cell activity changes stimulated by TENGs is stressed in tissue regeneration, physiological function rehabilitation, and electroporation‐based drug delivery for disease therapy. Finally, the challenges and opportunities of using TENGs for electrical stimulation are presented for cell engineering in the biosciences and health care.

T. Halski, K. Ptaszkowski, Lucyna Słupska et al.

BioMed Research International • 2013

Objectives. The main objective was to determine how the depth of probe placement affects functional and resting bioelectrical activity of the PFM and whether the recorded signal might be dependent on the direction in which the probe is rotated. Participants. The study comprised of healthy, nulliparous women between the ages of 21 and 25. Outcome Measures. Bioelectric activity of the PFM was recorded from four locations of the vagina by surface EMG and vaginal probe. Results. There were no statistically significant differences between the results during functional sEMG activity. During resting sEMG activity, the highest bioelectrical activity of the PFM was observed in the L1 and the lowest in the L4 and a statistically significant difference between the highest and the lowest results of resting sEMG activity was observed (P = 0.0043). Conclusion. Different electrodes placement during functional contraction of PFM does not affect the obtained results in sEMG evaluation. In order to diagnose the highest resting activity of PFM the recording plates should be placed toward the anterior vaginal wall and distally from the introitus. However, all of the PFM have similar bioelectrical activity and it seems that these muscles could be treated as a single muscle.

Federica A. Villa, A. Magnani, M. Maggioni et al.

Sensors • 2016

Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi-frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current-injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously.

M. Alvandi, P. Shahabi, G. G. Nejad et al.

The Neuroscience Journal of Shefaye Khatam • 2015

Introduction: Synchronization of bioelectrical activities of neurons contributes to the initiation of epileptiform activities occurred during a seizure attack. Absence seizures are characterized by synchronous and symmetric 2.5-4 Hz spike-wave discharges in children under 15 years old. More than half of children with absence epilepsy suffer from cognitive, education, and learning difficulties. The amplitude ratio of the theta and alpha waves is a reliable indicator for measuring of learning difficulties in children. The aim of this study was to evaluate the effect of L- and T-type voltage-dependent calcium channel blockers, verapamil and ethosuximide, on the amplitude of electroencephalogram (EEG) waves in WAG/Rij rats, a genetic animal model of absence epilepsy. Materials and Methods: 18 adult WAG/Rij rats in the age between 4 and 6 months were divided randomly into 3 groups. Using stereotaxic method, cannula was implanted in the peri-oral region of the primary somatosensory cortex for injection of drugs and recording electrodes were placed in the frontal and the occipital cortices. Electroencephalography was recorded 30 minutes before and one hour after drug injection. Results: The power of EEG sub-bands significantly decreased in the first 30 minutes after injection of verapamil and ethosuximide compared to the control group. Conclusion: Our data show that verapamil and ethosuximide can decrease the power of EEG sub-bands. However, they have not noticeable effect on theta to alpha ratio.

M. Stania, D. Chmielewska, Krystyna Kwaśna et al.

BMC Urology • 2015

BackgroundMore and more frequently stress urinary incontinence affects young healthy women. Hence, early implementation of effective preventive strategies in nulliparous continent women is essential, including pelvic floor muscle training. An initial evaluation based on the bioelectrical activity of the pelvic floor muscles (PFM) during whole-body vibration (WBV) would help to devise the best individualized training for prevention of stress urinary incontinence in woman. We hypothesized that synchronous WBV enhances bioelectrical activity of the PFM which depends on vibration frequency and peak-to-peak vibration displacement.MethodsThe sample consisted of 36 nulliparous continent women randomly allocated to three comparative groups. Group I and II subjects participated in synchronous whole-body vibrations on a vibration platform; the frequency and peak-to-peak displacement of vibration were set individually for each group. Control participants performed exercises similar to those used in the study groups but without the concurrent application of vibrations. Pelvic floor surface electromyography (sEMG) activity was recorded using a vaginal probe during three experimental trials limited to 30s, 60s and 90s. The mean amplitude and variability of the signal were normalized to the Maximal Voluntary Contraction – MVC.ResultsFriedman’s two-way ANOVA revealed a statistically significant difference in the mean normalized amplitudes (%MVC) of the sEMG signal from the PFM during 60s- and 90s-trials between the group exposed to high-intensity WBV and control participants (p < 0.05). Longer trial duration was associated with a statistically significant decrease in the variability of sEMG signal amplitude in the study and control groups (p < 0.05).ConclusionsSynchronous high-intensity WBV (40 Hz, 4 mm) of long duration (60s, 90s) significantly enhances the activation of the PFM in young continent women. Prolonged maintenance of a static position significantly decreases the variability of sEMG signal amplitude independent of whole-body vibrations. Single whole-body vibrations in nulliparous continent women does not cause pelvic floor muscle fatigue.Trial registrationThe trial was registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12615000966594); registration date: 15/09/2015.