Arka Chatterjee, Avijit Das, Kundan Saha et al.

Advanced Sensor Research • 2023

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

Ananta Ghimire, Omkar Zore, Vindya Thilakarathne et al.

Sensors • 0

<jats:p>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 &gt;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.</jats:p>

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

Frontiers of Environmental Science &amp; Engineering • 2024

<jats:title>Abstract</jats:title> <jats:p>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, <jats:italic>Magnetospirillum magneticum</jats:italic> strain AMB-1 and <jats:italic>Magnetospirillum gryphiswaldense</jats:italic> strain MSR-1, are electroactive. Both <jats:italic>M. magneticum</jats:italic> and <jats:italic>M. gryphiswaldense</jats:italic> were able to generate current in microbial fuel cells with maximum power densities of 27 and 11 µW/m<jats:sup>2</jats:sup>, respectively. In the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite (Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>). In addition, <jats:italic>M. magneticum</jats:italic> could reduce poorly crystalline iron oxide (FeOOH). Our study adds <jats:italic>M. magneticum</jats:italic> and <jats:italic>M. gryphiswaldense</jats:italic> to the growing list of known electroactive bacteria, and implies that electroactivity might be common for bacteria within the <jats:italic>Magnetospirillum</jats:italic> genus. </jats:p>

Naser Mohammadi, Juan Carlos Abrego-Martinez, Mohamed Mohamedi

Molecules • 0

<jats:p>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.</jats:p>

Emilie Lyautey, Amandine Cournet, Soizic Morin et al.

Applied and Environmental Microbiology • 2011

<jats:title>ABSTRACT</jats:title> <jats:p> 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 <jats:italic>a</jats:italic> 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 ( <jats:italic>Actinobacteria</jats:italic> , <jats:named-content content-type="genus-species">Firmicutes</jats:named-content> , <jats:italic>Bacteroidetes</jats:italic> , and <jats:italic>Alpha</jats:italic> -, <jats:italic>Beta</jats:italic> -, and <jats:named-content content-type="genus-species">Gammaproteobacteria</jats:named-content> ) 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 <jats:italic>in situ</jats:italic> phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions. </jats:p>

JinWon Lee, Sungwook Chung, Seok Kim

Journal of Nanoscience and Nanotechnology • 2020

<jats:p>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.</jats:p>

Yaovi Holade, Claudia Morais, Karine Servat et al.

Phys. Chem. Chem. Phys. • 0

<p>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.</p>

Gertrude Fomo, Tesfaye Waryo, Christopher Sunday et al.

Sensors • 0

<jats:p>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.</jats:p>

Long Hoang Bao Nguyen, Jean‐Sébastien Filhol

Advanced Energy Materials • 2023

<jats:title>Abstract</jats:title><jats:p>The electrochemical activity of solvated Ca<jats:sup>2+</jats:sup> 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<jats:sup>2+</jats:sup> center and the organic part of the solvation sphere, leading to a direct Ca<jats:sup>2+</jats:sup> 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<jats:sup>2+</jats:sup> reduction, unless a partial desolvation occurs. Consequently, an effective Ca<jats:sup>2+</jats:sup> 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<jats:sup>2+</jats:sup> reduction potential in an accessible voltage range together with an effective Ca<jats:sup>2+</jats:sup> 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.</jats:p>

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

Journal of The Electrochemical Society • 2022

<jats:p>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 <jats:italic>Salinivibrio sp.</jats:italic> 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<jats:italic>alinivibrio sp.</jats:italic> 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 <jats:italic>Salinivibrio sp</jats:italic>. EAGSL, the pairing of electroanalytical and genomic methods can provide a framework of study for other novel electroactive species.</jats:p> <jats:p> <jats:inline-formula> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="jesac4fee-ga.jpg" xlink:type="simple"/> </jats:inline-formula> </jats:p>

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

Nanoscale Research Letters • 2012

<jats:title>Abstract</jats:title> <jats:p>Carbon-coated ZnWO<jats:sub>4</jats:sub> [C-ZW] nanorods with a one-dimensional core/shell structure were synthesised using hydrothermally prepared ZnWO<jats:sub>4</jats:sub> and malic acid as precursors. The effects of the carbon coating on the ZnWO<jats:sub>4</jats:sub> 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 <jats:italic>D</jats:italic> and <jats:italic>G</jats:italic> bands of carbon were clearly observed at around 1,350 and 1,600 cm<jats:sup>-1</jats:sup>, 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<jats:sub>4</jats:sub> 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<jats:sup>-1</jats:sup>, even at a high current rate of 3 C, which is much higher than pure ZnWO<jats:sub>4</jats:sub> nanorods.</jats:p>

Ludek Havran, Sabina Billová, Emil Palecek

Electroanalysis • 2004

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

Allison M. Speers, Gemma Reguera

Applied and Environmental Microbiology • 2012

<jats:title>ABSTRACT</jats:title> <jats:p> <jats:named-content content-type="genus-species">Geobacter</jats:named-content> 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 <jats:named-content content-type="genus-species">Geobacter sulfurreducens</jats:named-content> 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 <jats:named-content content-type="genus-species">Geobacter</jats:named-content> -driven fuel cells and identify microbial constraints that can be targeted to develop better-performing strains and increase the performance of bioelectrochemical systems. </jats:p>

K. Sudhakara Prasad, Charuksha Walgama, Sadagopan Krishnan

RSC Advances • 0

<p>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⁻²is achieved for the first time.</p>

Aiping Zhu, Hongsheng Wang, Chaoqun Zhang

Polymer Composites • 2018

<jats:p>In this work, the novel nanofiber composites of graphene/poly(aniline‐co‐5‐aminosalicylic acid) were prepared by <jats:italic>in situ</jats:italic> reduction of graphene oxide (GO) followed by <jats:italic>in situ</jats:italic> 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</jats:p>

Audacity Maringa, Tebello Nyokong

Journal of Porphyrins and Phthalocyanines • 2014

<jats:p>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<jats:sub>p</jats:sub>) 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<jats:sub>p</jats:sub>= 0.78 V and the modified electrodes gave E<jats:sub>p</jats:sub>= 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.</jats:p>

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

RASAYAN Journal of Chemistry • 2023

<jats:p>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.</jats:p>

Emil Paleček, Veronika Ostatná

Electroanalysis • 2007

<jats:title>Abstract</jats:title><jats:p>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 &gt;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.</jats:p>

Yanyan Wang, Kalle Levon

Macromolecular Symposia • 2012

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

Tetsuya Osaka, Toshiyuki Momma, Ken Nishimura

Chemistry Letters • 1992

<jats:title>Abstract</jats:title> <jats:p>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.</jats:p>

Mohammed Mouhib, Melania Reggente, Lin Li et al.

• 0

<jats:p>Extracellular electron transfer (EET) engineering in <jats:italic>Escherichia coli</jats:italic> 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, <jats:italic>E. coli</jats:italic> 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 <jats:italic>E. coli</jats:italic> nitrate reductase and the Mtr complex from the exoelectrogen <jats:italic>Shewanella oneidensis</jats:italic> MR-1 enhanced EET, the highest efficiency was achieved by implementing the complete Mtr pathway from <jats:italic>S. oneidensis</jats:italic> MR1 in <jats:italic>E. coli</jats:italic>. 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.</jats:p>

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

Microbial Biotechnology • 2024

<jats:title>Abstract</jats:title><jats:p>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<jats:sub>2</jats:sub> 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 <jats:italic>Geobacter sulfurreducens</jats:italic>. 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.</jats:p>

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.

K. Ptaszkowski, R. Zdrojowy, Lucyna Słupska et al.

European Journal of Physical and Rehabilitation Medicine • 2017

BACKGROUND Menopausal women often experience the prolapse of the uterus, bladder and rectum resulting from the failure and weakening of the pelvic floor muscles (PFM). Strengthening of the PFM through the standard exercises is recognized as an effective way of preventive measures and conservative treatment of the symptoms listed above, but still need to be improved. AIM The goal was the objective assessment of resting and functional bioelectrical activity of PFM in women during menopause and its comparison in three different positions of the pelvis: anterior pelvic tilt - position 1 (P1), posterior pelvic tilt - position 2 (P2), and neutral pelvic tilt - position 3 (P3). DESIGN Prospective, cross-sectional observational study. SETTING Department and Clinic of Urology of a University Hospital. POPULATION The target group of this study included women in the menopausal period (inpatient and outpatient). METHODS The study evaluating resting and functional activity of the PFM depending on the orientation of pelvis. Bioelectric activity was assessed with an electromyographic instrument (sEMG) and endovaginal electrodes. The inclination angle was measured with an inclinometer. The comparisons of results between the values obtained in P1, P2, and P3 were performed using one-way Analysis of Variance (ANOVA). RESULTS One hundred thirty-one registered for the study were screened for inclusion and exclusion criteria and on the basis of the results 82 participants were enrolled for analysis. The highest mean resting activity of sEMG PFM (µV) was observed in P2 and it amounted to 11.6 µV (SD=5.5 µV) in P1 the value equaled 9.8 µV (SD=4.8 µV) and P3-9.0 µV (SD=4.2 µV). The results revealed a significant statistical difference (main effect: P=0.0007). Considering the functional sEMG activity of PFM (µV), the highest mean value was recorded in P2. CONCLUSIONS Posterior pelvic tilt position determines higher resting and functional bioelectric activity of PFM. Additionally, electromyographic activity of PFM increases during the pelvic movement backwards. CLINICAL REHABILITATION IMPACT These positions should be implemented in therapy in order to improve the effectiveness of the effect on the pelvic floor.

Amir Javan-Khoshkholgh, A. Farajidavar

Sensors • 2019

High-resolution (HR) mapping of the gastrointestinal (GI) bioelectrical activity is an emerging method to define the GI dysrhythmias such as gastroparesis and functional dyspepsia. Currently, there is no solution available to conduct HR mapping in long-term studies. We have developed an implantable 64-channel closed-loop near-field communication system for real-time monitoring of gastric electrical activity. The system is composed of an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU) connected to a computer. Simultaneous data telemetry and power transfer between the IU and WU is carried out through a radio-frequency identification (RFID) link operating at 13.56 MHz. Data at the IU are encoded according to a self-clocking differential pulse position algorithm, and load shift keying modulated with only 6.25% duty cycle to be back scattered to the WU over the inductive path. The retrieved data at the WU are then either transmitted to the SU for real-time monitoring through an ISM-band RF transceiver or stored locally on a micro SD memory card. The measurement results demonstrated successful data communication at the rate of 125 kb/s when the distance between the IU and WU is less than 5 cm. The signals recorded in vitro at IU and received by SU were verified by a graphical user interface.

J. Kabaciński, A. Fryzowicz, A. Błaszczyk et al.

Sports Biomechanics • 2020

ABSTRACT In sweep rowers, the lower extremities muscle strength translates into the driving force of the boat. Therefore, isokinetic assessment of muscle torque is used by coaches as an indicator of the level of athletes’ preparation for competitions. A total of 22 elite sweep rowers performed an isokinetic test of knee joint flexors and extensors, and a test on an asymmetric ergometer with the electromyography measures. Significantly higher quadriceps peak torque was shown during the beginning than the end of the preparatory period (p < 0.05). However, there was no significant knee peak torque difference between the lower extremities (p = 0.398). In the case of the electromyography test of quadriceps, hamstrings and lumbar erector spinae, analysis demonstrated significant bioelectrical activity differences between the sides (p < 0.05). Lower values of quadriceps peak torque at the end of the preparatory period may result from a decrease in the number of power training units during the entire preparatory period. A similar muscle strength between both lower extremities seems to be the correct result in the context of injury prevention. In turn, significant bioelectrical activity differences between the sides possibly are associated with the asymmetric movement pattern in sweep rowers.

M. Vorkapić, A. Savić, M. Janković et al.

PLOS ONE • 2020

Background Clinical and animal studies have found that anxiety and depression are significantly more common after acute myocardial infarction (AMI). The medial prefrontal cortex (PFC) has a dual role: in higher brain functions and in cardiovascular control, making it a logical candidate for explaining the perceived bidirectional heart-brain connection. We used parallel Electrocardiography (ECG) and Electrocorticography (ECoG) registration to investigate AMI-induced changes in medial PFC bioelectrical activity in a rat model of AMI. Materials and methods Adult male Wistar albino rats were used in the study. Gold-plated recording electrodes were implanted over the frontal cortex for ECoG recording. ECG was recorded via two holter electrodes attached on the skin of the back fixed in place by a jacket. Induction of AMI was performed by isoprenaline (150 mg/kg, i.p.). ECoG and ECG signals were registered at baseline, during 3 hours after isoprenaline administration and at 24 hours after isoprenaline administration. Results Significant increases of theta, alpha, and beta electroencephalographic (EEG) band power were observed in different time intervals after isoprenaline administration. Significant increase of theta band peak frequency was also observed during the first hour after isoprenaline administration. No statistically significant differences in band-power activity were found between the pre-isoprenaline measurements and 24 hours after administration. Conclusion Our results demonstrate significant increases in EEG band power of alpha beta and theta bands during isoprenaline-induced AMI model. These are the first findings to connect heart damage during isoprenaline- induced AMI to disturbances in the cortical bioelectrical activity.

Yosuke Yamada, T. Yoshida, H. Murakami et al.

Scientific Reports • 2022

The phase angle (PhA), measured via bioelectrical impedance analysis, is considered an indicator of cellular health, where higher values reflect higher cellularity, cell membrane integrity, and better cell function. This study aimed to examine the relationship between PhA and exercise habits or objectively measured physical activity. We included 115 people aged 32–69 years. The body composition and PhA were measured using a bioelectrical impedance device. Physical activity and sedentary behavior (SB) were assessed using a triaxial accelerometer. Exercise habits were also obtained through structured interviews, and participants were categorized into the no exercise habit (No-Ex), resistance training exercise habit (RT), or aerobic training exercise habit (AT) groups. Objectively measured moderate-to-vigorous physical activity or step count significantly correlated with PhA, independent of age, sex, height, percent body fat, body cell mass, and leg muscle power. In contrast, SB was not significant determinants of PhA. People who exercised regularly (RT or AT) had significantly higher PhA values than did those in the No-Ex group. Furthermore, the PhA was not significantly different between the RT and AT groups. Regularly engaging in exercise with moderate-to-vigorous intensity may improve or maintain muscle cellular health and muscle quality.

A. Parise, G. N. Reissig, Luis Felipe Basso et al.

Frontiers in Plant Science • 2021

In our study, we investigated some physiological and ecological aspects of the life of Cuscuta racemosa Mart. (Convolvulaceae) plants with the hypothesis that they recognise different hosts at a distance from them, and they change their survival strategy depending on what they detect. We also hypothesised that, as an attempt of prolonging their survival through photosynthesis, the synthesis of chlorophylls (a phenomenon not completely explained in these parasitic plants) would be increased if the plants don’t detect a host. We quantified the pigments related to photosynthesis in different treatments and employed techniques such as electrophysiological time series recording, analyses of the complexity of the obtained signals, and machine learning classification to test our hypotheses. The results demonstrate that the absence of a host increases the amounts of chlorophyll a, chlorophyll b, and β-carotene in these plants, and the content varied depending on the host presented. Besides, the electrical signalling of dodders changes according to the species of host perceived in patterns detectable by machine learning techniques, suggesting that they recognise from a distance different host species. Our results indicate that electrical signalling might underpin important processes such as foraging in plants. Finally, we found evidence for a likely process of attention in the dodders toward the host plants. This is probably to be the first empirical evidence for attention in plants and has important implications on plant cognition studies.

Łukasz Oleksy, A. Mika, I. Sulowska-Daszyk et al.

International Journal of Environmental Research and Public Health • 2021

The aim of the study was to determine the between-trial and between-day reliability of the Glazer protocol and our multi-activity surface electromyography (sEMG) measurement protocol for pelvic floor muscle (PFM) evaluation. The bioelectrical activity of PFM was collected using an endovaginal electrode in 30 young, Caucasian, nulliparous women (age 22–27, 168.6 ± 5.1 cm, 57.1 ± 11.8 kg). The between-trial and between-day reliability of the original Glazer protocol and the new multi-activity sEMG protocol were assessed during the following phases: pre-baseline rest, phasic (flick) contractions, tonic contractions, endurance contraction, and post-baseline rest. The Glazer protocol was characterized by poor and moderate measurement reliability. The time-domain parameters for the rise and fall of the signal amplitude and median frequency showed poor between-trial and between-day reliability. The mean and peak amplitudes indicated mainly good between-trial and moderate between-days reliability. Our protocol showed moderate to excellent reliability of both time-domain and quantitative parameters of muscle recruitment. In our protocol, the frequency-domain parameters describing muscle fatigue demonstrated much higher reliability than in the case of the Glazer protocol. The most important information obtained in this study was the significant improvement of diagnostic validity in PFM bioelectrical activity evaluation. The higher reliability of our sEMG protocol compared to original Glazer protocol allowed us to suggest that protocol modifications and changes in sEMG signal processing methods were effective in the improvement of PFM assessment quality. The new parameters calculated from the sEMG signal proposed in our sEMG protocol allowed us to obtain additional clinically important information about PFM dysfunctions regarding specific deficits of muscle contraction such as decrease in muscle strength; endurance or coordination related to, e.g., stress urinary incontinence; or pelvic floor muscle imbalance after childbirth.

K. Kalitin, G. V. Pridvorov, A. Spasov et al.

Journal of Volgograd State Medical University • 2022

Since ischemic stroke is an extremely common and dangerous pathology, it is important to use drugs with neuroprotective activity. The depth and degree of brain damage due to ischemia are reflected in its bioelectrical activity. This makes it possible to use the electrocorticography or intracranial electroencephalography (EEG) as a tool for evaluating the effectiveness of neuroprotective therapy. In the present study the neuroprotective properties of the experimental compound RU-1205 and the kappa-opioid agonist butorphanol were analyzed. The neuroprotective effect of the substances was assessed by measuring the extent of the neurological deficit and the changes in bioelectrical activity of the ischemic brain of rats. Compound RU-1205 (10 mg/kg, i.v.) as well as the reference drug butorphanol (2,5 mg/kg, i.v.) restored to normal neurological status and power of the EEG signal in delta and theta frequency bands.

Dariia Liashko

ScienceRise • 0

<jats:p>The object of the study. Experimental research of music therapy methods. The problem to be solved. Determining the influence of selected musical composition of the audible frequency spectrum on the bioelectrical activity of students' brains, in particular alpha-, beta- and theta-rhythms. Main scientific results. The dependence of the influence on the bioelectrical activity of the brain of the compositions of the three frequency bands both individually and the composition as a whole is revealed. The dependence of alpha, beta and theta rhythms is shown. The area of ​​practical use of the research results. Medical institutions specializing in the treatment of disorders of the central nervous system, organic brain damage, stress, and its effective psychological rehabilitation. An innovative technological product. A technique of music therapy that allows to determine how different frequency ranges affect the bioelectrical activity of the human brain. The area of application of an innovative technological product. Clinical practice of using a music therapy.</jats:p>

I. A. Kostenko, M. V. Aleksandrov, V. S. Chernyi

Toxicological Review • 0

<jats:p>The aim of the stady wos to investigate the mechanisms of suppression of cerebral bioelectrical activity under adverse effects caused by neurotoxicants using inhalation anesthesia with sevoflurane. The research included 19 cases (male/female 12/7, aged 19—55, BMIs under 35) with intracerebral tumors. Patients were under medical observation and neurosurgical treatment. Invasive procedures were carried out under sevoflurane-based general anesthesia with a dose of anesthetic varying from 0,8 to 1,3 MAC (minimum alveolar concentration). Technologically advanced neurosurgical procedures involved neurophysiological polymodal monitoring, which included EEG and ECoG testing. Probit analysis results showed that, with cerebral cortex bioelectrical activity suppression index equal to 32±8%, nearly half the cases displayed a formation of an «outburst-suppression» type of pattern on the scalp EEG. The condition for half the cases displaying a formation of this type of periodic pattern is the suppression index equaling 58±7% on ECoG. Space-and-time evolution of suppression patterns, formed on the cerebral cortex, is the main reason for persistence of uninterrupted activity on EEG. The obtained results allow to further define principles of neurodynamics, which apply to acute intoxication with neurotoxicants. With regard to relative similarity of intoxication-induced coma cases, registration of periodic EEG patterns even with a low suppression index indicates a more severe form of cerebral insufficiency.</jats:p>

Vilma Kisnierienë, Vidmantas Sakalauskas

Open Life Sciences • 2007

<jats:title>Abstract</jats:title><jats:p>Aluminium induced membrane potential (Em) changes and potential changes during repolarization phase of the action potential (AP) in the internodal cells of Nitellopsis obtusa after blocking H+-ATPase activity by DCCD were investigated. Micromolar concentrations of DCCD are sufficient to give complete and irreversible inhibition of proton pumping. The membrane potential was measured by conventional glass-microelectrode technique. We found that the half-amplitude pulse duration differs significantly between standard conditions, after DCCD application, and after H+-ATPase blocking and subsequent Al3+ treatment: 4.9, 7.7 and 17.2 seconds, respectively. We propose that in the short term (2 hours) treatment of Al3+, the decrease in membrane potential was compensated for by H+-ATPase activity. Blocking H+-ATPase activity by DCCD can enhance the influence of Al3+ on the bioelectrical activity of cell membranes.</jats:p>

David A. Finkelstein, L. Tender, J. Zeikus

Environmental Science &amp; Technology • 2006

The benthic microbial fuel cell (BMFC) generates power by coupling oxidation of fuels naturally residing in marine sediments with reduction of oxygen in overlying waters. A central feature of BMFCs is spontaneous colonization of the anode by mineral-reducing microorganisms indigenous to marine sediments that catalyze the power-generating anodic reactions. Described here is a preliminary investigation of how the anode potential affects this feature. Different oxidative potentials were applied to a set of anodes under conditions known to promote anode enrichment of acetate oxidizing/mineral reducing microorganisms. In-situ analysis of current, acetate consumption, and reducing ability of the anode colonies suggest thatthe microorganisms conserve a significant portion (as much as 95%) of potential energy liberated from oxidation of acetate and reduction of the anode for their own metabolic benefit. The implication of this result with respect to BMFCs, and other MFCs utilizing electrode-reducing microbial catalysts, is that although the microorganisms enable long-term stability of such fuel cells, they may significantly impact efficiency of power output per equivalent of fuel consumed.