Haixian Liu, Z. Jin, Zhi Wang et al.

SSRN Electronic Journal • 2022

Under-deposit corrosion, a typical corrosion type, is a major threat to the safe running of pipeline steel in marine environment. Under-deposit corrosion behaviour and mechanism still require further investigation, especially when there is participation of microorganisms. In this work, the inhibition of corrosion of deposit-covered X80 pipeline steel due to the presence of Pseudomonas stutzeri in seawater containing CO2 was investigated using weight loss, electrochemical measurements, a wire beam electrode and surface analysis. The results show that steel corrosion rates decline rapidly due to the covered deposit in the presence or absence P. stutzeri, but corrosion rates were slower in the presence of P. stutzeri. The highest corrosion rates were (0.365 ± 0.021) mm/y and (0.230 ± 0.001) mm/y in abiotic and biotic conditions, respectively. The corrosion inhibition efficiency of P. stutzeri was reduced in the presence of deposits, because the deposits led to a lowered biological activity. The galvanic current density between deposit-covered and bare specimens in seawater was weakened by P. stutzeri, leading to diminshed corrosion, especially pitting corrosion.

Glenn Quek, R. J. Vázquez, Samantha R McCuskey et al.

Angewandte Chemie International Edition • 2023

Interfacing bacteria as biocatalysts with an electrode provides the basis for emerging bioelectrochemical systems that enable sustainable energy interconversion between electrical and chemical energy. Electron transfer rates at the abiotic-biotic interface are, however, often limited by poor electrical contacts and the intrinsically insulating cell membranes. Herein, we report the first example of an n-type redox-active conjugated oligoelectrolyte, namely COE-NDI, which spontaneously intercalates into cell membranes and mimics the function of endogenous transmembrane electron transport proteins. The incorporation of COE-NDI into Shewanella oneidensis MR-1 cells amplifies current uptake from the electrode by 4-fold, resulting in the enhanced bio-electroreduction of fumarate to succinate. Moreover, COE-NDI can serve as a "protein prosthetic" to rescue current uptake in non-electrogenic knockout mutants.

L. D. de Moura Torquato, Dario Lacalamita, Rosa Maria Matteucci et al.

Journal of The Electrochemical Society • 2024

The development of bioelectrochemical systems requires careful selection of both their biotic and abiotic components to obtain sustainable devices. Herein, we report a biophotoelectrode obtained with polyhydroxybutyrate (PHB), a biopolymer, which purple non-sulphur bacteria produce as an energy stock under specific environmental conditions. The electrode was obtained by casting a mixture composed of PHB and carbon fibers in a 3:2 mass ratio. Following, the composite material was modified with polydopamine and thermally treated to obtain a hydrophilic electrode with improved electrochemical behavior. The bio-based electrode was tested with metabolically active cells of Rhodobacter capsulatus embedded in a biohybrid matrix of polydopamine. The system achieved enhanced catalytic activity under illumination, with an 18-fold increase in photocurrent production compared to biophotoelectrodes based on glassy carbon, reaching a current density of 12 ± 3 µA cm-2, after 30 min of light exposure at +0.32 V. The presented biocompatible electrode provides a sustainable alternative to metal-based and critical raw material-based electrodes for bioelectrochemical systems.

V. B. Wang, Jenny Q. Du, Xiaofen Chen et al.

Physical Chemistry Chemical Physics • 2013

It is important to tailor biotic-abiotic interfaces in order to maximize the utility of bioelectronic devices such as microbial fuel cells (MFCs), electrochemical sensors and bioelectrosynthetic systems. The efficiency of electron-equivalent extraction (or injection) across such biotic-abiotic interfaces is dependent on the choice of the microbe and the conductive electrode material. In this contribution, we show that spontaneous intercalation of a conjugated oligoelectrolyte, namely 4,4'-bis(4'-(N,N-bis(6''-(N,N,N-trimethylammonium)hexyl)amino)-styryl)stilbene tetraiodide (DSSN+), into the membranes of Escherichia coli leads to an increase in current generation in MFCs containing carbon-based electrodes. A combination of scanning electron microscopy (SEM) and confocal microscopy was employed to confirm the incorporation of DSSN+ into the cell membrane and biofilm formation atop carbon felt electrodes. Current collection was enhanced by more than 300% with addition of this conjugated oligoelectrolyte. The effect of DSSN+ concentration on electrical output was also investigated. Higher concentrations, up to 25 μM, lead to an overall increase in the number of charge equivalents transferred to the charge-collecting electrode, providing evidence in support of the central role of the synthetic system in improving device performance.

Novianti Novianti, R. V. Manurung, A. Arifin

IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) • 2020

Cadmium (Cd) is a heavy metal that has high toxicity. Cadmium levels need to be considered in an environment that can accumulate and can poison all biotic components. In this research measurements of cadmium metal using bismuth-modified carbon screen electrode  used cyclic voltammetry method. The parameters considered are the resolution of the comparative electrodes and the voltage produced from variations in cadmium concentration. The test results prove the stability of three sensors each at a voltage of 3.3 - 4.6 mV, 9.3-11.4 mV, and 27.4 - 29.8 mV. While the results of the cyclic voltammetry characterization test vary depending on the concentration of cadmium. Concentrations of 0.5-100 ng / mL produce an oxidation peak at a current of 2.03 x 10-5 - 5.00 x 10-5 A. These results show a directly proportional relationship between the cadmium concentration and the resulting current.

Abhishek Prasad, Q. Xue, Robert Dieme et al.

Frontiers in Neuroengineering • 2014

Pt/Ir electrodes have been extensively used in neurophysiology research in recent years as they provide a more inert recording surface as compared to tungsten or stainless steel. While floating microelectrode arrays (FMA) consisting of Pt/Ir electrodes are an option for neuroprosthetic applications, long-term in vivo functional performance characterization of these FMAs is lacking. In this study, we have performed comprehensive abiotic-biotic characterization of Pt/Ir arrays in 12 rats with implant periods ranging from 1 week up to 6 months. Each of the FMAs consisted of 16-channel, 1.5 mm long, and 75 μm diameter microwires with tapered tips that were implanted into the somatosensory cortex. Abiotic characterization included (1) pre-implant and post-explant scanning electron microscopy (SEM) to study recording site changes, insulation delamination and cracking, and (2) chronic in vivo electrode impedance spectroscopy. Biotic characterization included study of microglial responses using a panel of antibodies, such as Iba1, ED1, and anti-ferritin, the latter being indicative of blood-brain barrier (BBB) disruption. Significant structural variation was observed pre-implantation among the arrays in the form of irregular insulation, cracks in insulation/recording surface, and insulation delamination. We observed delamination and cracking of insulation in almost all electrodes post-implantation. These changes altered the electrochemical surface area of the electrodes and resulted in declining impedance over the long-term due to formation of electrical leakage pathways. In general, the decline in impedance corresponded with poor electrode functional performance, which was quantified via electrode yield. Our abiotic results suggest that manufacturing variability and insulation material as an important factor contributing to electrode failure. Biotic results show that electrode performance was not correlated with microglial activation (neuroinflammation) as we were able to observe poor performance in the absence of neuroinflammation, as well as good performance in the presence of neuroinflammation. One biotic change that correlated well with poor electrode performance was intraparenchymal bleeding, which was evident macroscopically in some rats and presented microscopically by intense ferritin immunoreactivity in microglia/macrophages. Thus, we currently consider intraparenchymal bleeding, suboptimal electrode fabrication, and insulation delamination as the major factors contributing toward electrode failure.

B. J. Gross, M. El‐Naggar

Review of Scientific Instruments • 2015

Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

V. Vasilenko, I. Arkadeva, V. Bogdanovskaya et al.

Energies • 2020

The demand for alternative sources of clean, sustainable, and renewable energy has been a focus of research around the world for the past few decades. Microbial/enzymatic biofuel cells are one of the popular technologies for generating electricity from organic substrates. Currently, one of the promising fuel options is based on glucose due to its multiple advantages: high energy intensity, environmental friendliness, low cost, etc. The effectiveness of biofuel cells is largely determined by the activity of biocatalytic systems applied to accelerate electrode reactions. For this work with aerobic granular sludge as a basis, a nitrogen-fixing community of microorganisms has been selected. The microorganisms were immobilized on a carbon material (graphite foam, carbon nanotubes). The bioanode was developed from a selected biological material. A membraneless biofuel cell glucose/oxygen, with abiotic metal catalysts and biocatalysts based on a microorganism community and enzymes, has been developed. Using methods of laboratory electrochemical studies and mathematical modeling, the physicochemical phenomena and processes occurring in the cell has been studied. The mathematical model includes equations for the kinetics of electrochemical reactions and the growth of microbiological population, the material balance of the components, and charge balance. The results of calculations of the distribution of component concentrations over the thickness of the active layer and over time are presented. The data obtained from the model calculations correspond to the experimental ones. Optimization for fuel concentration has been carried out.

Stéphane Werwinski, J. Wharton, M. Nie et al.

ACS Applied Materials & Interfaces • 2021

Reliable and accurate in situ sensors capable of detecting and quantifying troublesome marine biofilms on metallic surfaces are increasingly necessary. A 0.2 mm diameter gold electrochemical sensor was fully characterized using cyclic voltammetry in abiotic and biotic artificial seawater media within a continuous culture flow cell to detect the growth and development of an aerobic Pseudoalteromonas sp. biofilm. Deconvolution of the abiotic and biotic responses enable the constituent extracellular electron transfer and biofilm responses to be resolved. Differentiation of enhanced oxygen reduction kinetics within the aerobic bacterial biofilm is linked to enzyme and redox mediator activities.

Long Zou, Xianxian Wu, Yun-hong Huang et al.

Frontiers in Microbiology • 2019

The extracellular electron transfer (EET) that connects the intracellular metabolism of electroactive microorganisms to external electron donors/acceptors, is the foundation to develop diverse microbial electrochemical technologies. For a particular microbial electrochemical device, the surface chemical property of an employed electrode material plays a crucial role in the EET process owing to the direct and intimate biotic-abiotic interaction. The functional modification of an electrode surface with redox mediators has been proposed as an effectual approach to promote EET, but the underlying mechanism remains unclear. In this work, we investigated the enhancement of electrochemically polymerized riboflavin interface on the bidirectional EET of Shewanella putrefaciens CN32 for boosting bioelectrocatalytic ability. An optimal polyriboflavin functionalized carbon cloth electrode achieved about 4.3-fold output power density (∼707 mW/m2) in microbial fuel cells and 3.7-fold cathodic current density (∼0.78 A/m2) for fumarate reduction in three-electrode cells compared to the control, showing great increases in both outward and inward EET rates. Likewise, the improvement was observed for polyriboflavin-functionalized graphene electrodes. Through comparison between wild-type strain and outer-membrane cytochrome (MtrC/UndA) mutant, the significant improvements were suggested to be attributed to the fast interfacial electron exchange between the polyriboflavin interface with flexible electrochemical activity and good biocompatibility and the outer-membrane cytochromes of the Shewanella strain. This work not only provides an effective approach to boost microbial electrocatalysis for energy conversion, but also offers a new demonstration of broadening the applications of riboflavin-functionalized interface since the widespread contribution of riboflavin in various microbial EET pathways together with the facile electropolymerization approach.

M. Asif, A. Aziz, Ghazala Ashraf et al.

ACS Applied Materials & Interfaces • 2018

The development of structurally modified metal oxide heteroarchitectures with higher energy facets exposed has been of extensive research interests because of their unique construction and synergy effect of multifunctioning characteristics. In this study, we reported for the first time the development of a distinct type of gold nanoislands (AuNIs) on metal oxides (i.e., Cu2O-CuO) octadecahedral (ODH) heterostructures through the galvanic exchange reaction, where Cu2O not only acts as a stabilizer but also functions as a reductant. The electrocatalytic performance of the resultant core-shell Cu2O-CuO@AuNI ODH-based electrochemical sensing platform has been evaluated in ultrasensitive detection of sulfide as early disease diagnostics and bacterial marker. Owing to the synergistic collaboration of enhanced surface active sites, exposed {110} crystallographic facets, mixed valances of copper that encourage redox reactions at electrode material/analyte interface, and the polarization effect provide by AuNIs decorated onto the Cu2O surface, Cu2O-CuO@AuNI ODH-modified electrode has demonstrated striking electrochemical sensing performance toward sulfide oxidation in terms of broad linear range, real detection limit down to 1 nM (S/N = 3), and incredible durability and reproducibility. In virtue of marvelous efficiency, the proposed electrochemical sensor based on Cu2O-CuO@AuNI ODH has been employed in in situ sensitive detection of a ubiquitous amount of sulfide engendered by sulfate-reducing bacteria and real-time tracking of sulfide efflux from live cells as early diagnostic strategies.

S. Rusli, Siti Mariam Daud, Mimi Hani Abu Bakar et al.

Molecules • 2022

The biocathode in a microbial fuel cell (MFC) system is a promising and a cheap alternative method to improve cathode reaction performance. This study aims to identify the effect of the electrode combination between non-chemical modified stainless steel (SS) and graphite fibre brush (GFB) for constructing bio-electrodes in an MFC. In this study, the MFC had two chambers, separated by a cation exchange membrane, and underwent a total of four different treatments with different electrode arrangements (anodeǁcathode)—SSǁSS (control), GFBǁSS, GFBǁGFB and SSǁGFB. Both electrodes were heat-treated to improve surface oxidation. On the 20th day of the operation, the GFBǁGFB arrangement generated the highest power density, up to 3.03 W/m3 (177 A/m3), followed by the SSǁGFB (0.0106 W/m3, 0.412 A/m3), the GFBǁSS (0.0283 W/m3, 17.1 A/m3), and the SSǁSS arrangements (0.0069 W/m−3, 1.64 A/m3). The GFBǁGFB had the lowest internal resistance (0.2 kΩ), corresponding to the highest power output. The other electrode arrangements, SSǁGFB, GFBǁSS, and SSǁSS, showed very high internal resistance (82 kΩ, 2.1 kΩ and 18 kΩ, respectively) due to the low proton and electron movement activity in the MFC systems. The results show that GFB materials can be used as anode and cathode in a fully biotic MFC system.

Д.В. Заславский, А.В. Таганов, Е.Д. Заславская et al.

Дерматовенерология Косметология • 2023

<jats:p>Введение. Кожа пациентов с атопическим дерматитом имеет отличный от здоровых индивидуумов микробиом, а также характеризуется более высокой обсемененностью Staphylococcus aureus. Восстановление нормального соотношения микроорганизмов на поверхности кожи улучшает резистентность пациентов с атопическим дерматитом к инфицированию, а также способствует нормализации эпидермального барьера. Это объясняет целесообразность применения в терапии атопического дерматита топических средств, стабилизирующих микробиом кожи пациентов. Цель. Оценить эффективность и безопасность применения эмолиента – крема липидовосстанавливающего, содержащего биотический комплекс (BIOTIC COMPLEX: lactobacillus plantarum heal 19, олигосахарид и инулин), у детей с легким и среднетяжелым течением атопического дерматита. Материалы и методы. С декабря 2022 по март 2023 г. на базе клиники кожных болезней Санкт-Петербургского государственного педиатрического медицинского университета в наблюдательную программу были включены 28 детей в возрасте от 5 до 17 лет с легким и среднетяжелым течением атопического дерматита. Все пациенты получали терапию согласно федеральным клиническим рекомендациям по лечению атопического дерматита, а в качестве топической терапии применяли крем липидовосстанавливающий, содержащий биотический комплекс (BIOTIC COMPLEX), увлажняющие и смягчающие компоненты, а также разрешенный к применению у детей с 0 лет. Наблюдательная программа включала 4 визита (1-й, 3-й, 7-й и 14-й дни). На 1-м и 4-м визитах у пациентов была проведена оценка степени тяжести атопического дерматита с помощью индекса SCORAD, на каждом визите у пациентов проводили измерение показателей эпидермального барьера (увлажненность, pH, себуметрия) с помощью аппарата Multi Skin Test Center 750 (Германия). Результаты. На первом визите среднее значение SCORAD у пациентов составило 26,4, в то время как на завершающем визите – 9,3. У всех участников программы (n=28; 100%) в 1-й день наблюдалось умеренное шелушение кожи и зуд, у 8 (29%) – отмечались очаги лихенификации и эритемы. Уровень рН кожи на первом визите составил 6,73±0,46, увлажненность кожи – 30,8±5,4, содержание кожного сала – 0,6±0,2. На 7-й день (визит 3) у 26 пациентов (93%) не было шелушения, среднее значение рH кожи составило 6,11±0,27; гидратация кожи – 42,6±5,2; содержание кожного сала – 1,2±0,3. На последнем визите у всех пациентов не было обнаружено объективных признаков сухости кожи. Среднее значение SCORAD составило 9,3; рН кожи – 5,5±0,72; гидратация кожи – 51,6±4,7; содержание кожного сала – 1,6±0,6. 26 из 28 пациентов (93%) отметили полное отсутствие зуда за период применения крема липидовосстанавливающего с содержанием биотического комплекса (BIOTIC COMPLEX). В рамках проведения наблюдательной программы не было зарегистрировано побочных явлений, связанных с применением эмолиента, у пациентов. Заключение. По результатам динамической оценки отмечалось снижение индекса степени тяжести атопического дерматита в 2,8 раза у пациентов, применявших липидовосстанавливающий крем дважды в день. Разрешение объективных и субъективных проявлений атопического дерматита у подавляющего большинства пациентов отмечалось уже к 7-му дню применения крема. По завершении наблюдательной программы у пациентов было зарегистрировано полное восстановление показателей увлажненности и кислотности кожи.</jats:p> <jats:p>Introduction. The skin of patients with atopic dermatitis has a different microbiome than healthy individuals, and is also characterized by a higher contamination of Staphylococcus aureus. Restoration of the normal ratio of microorganisms on the skin surface improves the resistance of patients with atopic dermatitis to infection, and also contributes to the normalization of the epidermal barrier. This explains the expediency of using topical agents in the treatment of atopic dermatitis that stabilize the skin microbiome of patients. Objectives. To evaluate the efficacy and safety of using an emollient containing a biotic complex (BIOTIC COMPLEX: lactobacillus plantarum heal 19, oligosaccharide and inulin) in children with mild and moderate atopic dermatitis. Materials and methods. From December 2022 to March 2023, 28 children aged 5 to 17 years with mild and moderate atopic dermatitis were included in the observational program on the basis of the clinic of skin diseases of the St. Petersburg State Pediatric Medical University. All patients received therapy in accordance with federal clinical guidelines for the treatment of atopic dermatitis, and as a topical therapy they received a lipid-restoring cream containing a biotic complex, moisturizing and emollient components, and also approved for use in children from 0 years of age. The observation program consisted of 4 visits (1, 3, 7 and 14 days). At the first and fourth visits, the patients were assessed for the severity of atopic dermatitis using the SCORAD index, and at each visit, the epidermal barrier parameters (hydratation, pH, sebumetry) were measured in patients with "Multi Skin Test Center 750" (Germany). Results. Patients had a mean SCORAD of 26.4 at the first visit, while 9.3 at the final visit. All participants in the study (n=28; 100%) had moderate desquamation and itching on day 1, 8 (29%) had areas of lichenification and erythema. The pH level of the skin at the first visit was 6.73±0.46, skin hydratation – 30.8±5.4, sebum content – 0.6±0.2. On the 7th day of the study, 26 patients (93%) had no desquamation, the average skin pH was 6.11±0.27; skin hydration – 42.6±5.2; sebum content – 1.2±0.3. At the last visit, no objective signs of dry skin were found in all patients. The mean SCORAD was 9.3; skin pH – 5.5±0.72; skin hydration – 51.6±4.7; sebum content – 1.6±0.6. 26 out of 28 patients (93%) noted the complete absence of itching during the period of application of the lipid-restoring cream containing the biotic complex. During the study, there were no side effects associated with the use of the emollient in patients. Conclusion. According to the results of the dynamic assessment, there was a decrease in the severity index of atopic dermatitis by 2.8 times in patients who applied the lipid-restoring cream twice a day. The resolution of objective and subjective manifestations of atopic dermatitis in the vast majority of patients was noted already by the 7th day of applying the cream. At the end of the observational program, the patients showed a complete recovery of skin hydration and acidity.</jats:p>

Carlos Moreno

Glocalism • 0

<jats:p>Rethinking urban life in a world of massive disruptions (climate change, air pollution, nature, water biodiversity and now Covid-19) has become one of the greatest challenges of the 21st century. To face these crises we must urgently address lifestyles and mobility, move away from the omnipresent car and the petroleum era and question what kind of city we really want to live in. The proposition of Professor Carlos Moreno is the “15-Minute City” concept, in a compact zone (or the “30 Minute Territory” in a semi-dense or sparse zone), where inhabitants can access all their essential needs of life: living, working, supplying, caring, educating, enjoying. The 15-Minute City addresses the key components required for a sustainable world (ecological, social, economic) and integrates the concepts of chrono-urbanism, chronotopia, and topophilia. This reinvention of proximities utilizes the convergence of open data, digital mapping, geolocation and the massification of new services. Nevertheless, citizens and their quality of life are always at the heart of the 15-Minute City. It is thus a polycentric city which combines urban intelligence, social inclusion and technological innovation and ultimately defines itself as an urban life planning. Paris is among the world’s first cities to have implemented the 15-Minute City, where it is famously quoted as the “big-bang of proximities”. It has recognized this innovative approach based on a global and systemic vision of the city in order to meet the fundamental needs of its inhabitants and to urgently address the unprecedented challenges it is facing today. This concept has now become a global movement.</jats:p>

Gang Fan, Christopher M. Dundas, Austin J. Graham et al.

Proceedings of the National Academy of Sciences • 2018

<jats:title>Significance</jats:title><jats:p>Metabolic engineering benefits from the tunable and tightly controlled transformations afforded by biological systems. However, these reactions have generally been limited to naturally occurring pathways and products. In this work, we coopt metabolic electron transfer from<jats:italic>Shewanella oneidensis</jats:italic>to control the activity of an exogenous metal catalyst in an abiotic reaction scheme: atom-transfer radical polymerization. In the presence of<jats:italic>S. oneidensis</jats:italic>, polymerizations exhibited well-defined kinetics and yielded polymers with controlled molecular weights and low polydispersities. Additionally, polymerization activity was dependent on electroactive metabolism and specific electron transport proteins, both of which provide handles to control material synthesis. This work serves as a proof-of-principle toward expanding the scope of reactions available to metabolic engineers to include previously discovered transition-metal–catalyzed reactions.</jats:p>

Tao Wu, Qiang Xiong, Ranran Song et al.

The Analyst • 0

<jats:p>A scanning electrochemical microscope (SECM) combined with an Au–Cu dual-electrode tip was used to <jats:italic>in situ</jats:italic> monitor the effect of Cu<jats:sup>2+</jats:sup> on the membrane permeability of a single living cell.</jats:p>

Hideo Ochiai, Hitoshi Shibata, Yoshihiro Sawa et al.

Proceedings of the National Academy of Sciences • 1980

<jats:p> Living blue-green algae ( <jats:italic>Mastigocladus laminosus</jats:italic> ), immobilized on an SnO <jats:sub>2</jats:sub> optically transparent electrode with calcium alginate, functioned as an anodic photoelectrode on continuous illumination for periods of time adequate for use in a conventional electrochemical cell. This “living electrode” shows promise of use as a long-lived photoconverter of solar radiant energy to electric energy and as a suitable replacement for unstable chloroplast systems. </jats:p>

Oskar Staufer, Sebastian Weber, C Peter Bengtson et al.

Beilstein Journal of Nanotechnology • 0

<jats:p>The functional fusion of “living” biomaterial (such as cells) with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries “perfected” during billion years of evolution. To date, hardware–wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. <jats:italic>Nat. Biotech.</jats:italic> <jats:bold>2012,</jats:bold> <jats:italic>30,</jats:italic> 1240–1243). More recent approaches employ nanowires (NWs) able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. <jats:italic>Nat. Nano.</jats:italic> <jats:bold>2013,</jats:bold> <jats:italic>8,</jats:italic> 83–94). Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. <jats:italic>Nat Nanotechnol.</jats:italic> <jats:bold>2012,</jats:bold> <jats:italic>10,</jats:italic> 180–184) or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. <jats:italic>Nat. Nano.</jats:italic> <jats:bold>2013,</jats:bold> <jats:italic>9,</jats:italic> 142–147), vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. <jats:italic>Nano Lett.</jats:italic> <jats:bold>2007,</jats:bold> <jats:italic>7,</jats:italic> 2960–2965) or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording electrical responses from oxidative events occurring in intercellular regions of neuronal cultures (Zhang, D.; Rand, E.; Marsh, M.; Andrews, R.; Lee, K.; Meyyappan, M.; Koehne, J. <jats:italic>Mol. Neurobiol.</jats:italic> <jats:bold>2013,</jats:bold> <jats:italic>48,</jats:italic> 380–385). Employing monocrystalline gold, nanoelectrode interfaces, we have now achieved stable, functional access to the electrochemical machinery of individual <jats:italic>Physarum polycephalum</jats:italic> slime mold cells. We demonstrate the “symbionic” union, allowing for electrophysiological measurements, functioning as autonomous sensors and capable of producing nanowatts of electric power. This represents a further step towards the future development of groundbreaking, cell-based technologies, such as bionic sensory systems or miniaturized energy sources to power various devices, or even “intelligent implants”, constantly refueled by their surrounding nutrients.</jats:p>

Yoojin Cho, Da Eun Oh, Myungeun Kim et al.

Chemosensors • 0

<jats:p>Graphene, known for its outstanding physical and chemical properties, is widely used in various fields, including electronics and biomedicine. Reduced graphene oxide (rGO) is preferred for electrochemical applications due to its enhanced water solubility and dispersion. Electrochemically reduced graphene oxide (ErGO) is particularly advantageous as it can be prepared under mild conditions and simplifies sensor fabrication; however, ErGO-based electrochemical sensors often lack specificity. Bioreceptors like proteins, enzymes, and DNA/RNA aptamers are incorporated to provide high specificity. This study introduces a guanine (G)/cytosine (C)-modified ErGO electrode (G/C@ErGO-GCE) for the sensitive electrochemical detection of doxorubicin (DOX) with good selectivity. The G/C mixture acts as a bioreceptor and is anchored on the ErGO-GCE surface via π-π interactions. The G/C@ErGO-GCE was characterized using scanning electron microscopy, contact angle measurement, Raman spectroscopy, and electrochemical methods. The sensor demonstrated excellent dynamic range (DPV: 10 nM to 1 µM, CA: 30 nM to 1.3 µM), sensitivity (DPV: 2.17 µA/µM, CA: 6.79 µA/µM), limit of detection (DPV: 84 nM, CA: 34 nM), and selectivity for DOX detection, highlighting its potential for biomedical applications and pharmacokinetic studies.</jats:p>

Robert Northcutt, Jacob Maddox, Vishnu-Baba Sundaresan

Volume 2: Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting • 2016

<jats:p>The development of novel characterization techniques is critical for understanding the fundamentals of material systems. Bioinspired systems are regularly implemented but poorly defined through quantitative measurement. In an effort to specify the coupling between multiple domains seen in biologically inspired systems, high resolution measurement systems capable of simultaneously measuring various phenomena such as electrical, chemical, mechanical, or optical signals is required. Scanning electrochemical microscopy (SECM) and shear-force (SF) imaging are nanoscale measurement techniques which examine the electrochemical behavior at a liquid-solid or liquid-liquid interface and simultaneously probe morphological features. It is therefore a suitable measurement technique for understanding biological phenomena.</jats:p> <jats:p>SF imaging is a high resolution technique, allowing for nanoscale measurement of extensional actuation in materials with high signal to noise ratio. The sensing capabilities of SECM-SF techniques are dependent on the characteristics of the micro-scale electrodes (ultramicroelectrodes or UMEs) used to investigate surfaces. Current limitations to this technique are due to the fabrication process which introduces structural damping, reducing the signal produced. Additionally, despite the high cost of materials and processing, contemporary processes only produce a 10% yield. This article demonstrates a UME fabrication process with a 60% yield as well as improved amplitude (250% increase) and sensitivity (210% increase) during SF imaging. This process is expected to improve the signal to noise ratio of SF-based measurement systems. With these improvements, SECM-SF could become a more suitable technique for measuring cell or tissue activity, corrosion of materials, or coupled mechanics of synthetic faradaic materials.</jats:p>

, Pemika Teabnamang

• 0

<jats:p>Aluminum-air batteries have received considerable attention as an electrical power source due to their theoretical specific capacity reaching 2.98 Ah/g. Further, Al-air batteries are abundant and low cost. On the other hand, the aluminum in the batteries has a problem, such that it is subject to self-corrosion in alkaline. Herein, this work concentrates on the aluminum’s corrosive behavior and self-corrosion in methanol-3M KOH mixed solution containing different percentages of deionized water i.e. (0, 5, 10 and 20)%wt, using electrochemical (half-cell testing). The aluminum-air battery consists of: aluminum anode</jats:p>

M. Prosňanský, T. Watanabe, M. Kuroda

Water Science and Technology • 2005

<jats:p>Three biofilm-electrode reactors (BERs) with multiple cathodes were applied to investigate the effect of electrode configuration and flow direction on denitrification under laboratory-scale conditions. The distribution of nitrate, DO and pH varied among applied BERs, as a consequence of a different electrode position in the reactors, bringing about a difference in the performance. Flow-through configuration of electrodes with a downstream anode appears to be the most suitable configuration since nitrite did not accumulate in the effluent only in this experiment and the current-denitrification efficiency at low current densities was high. Thus, it is recommended for a low-loading operation.</jats:p>

Girish Tigari, J.G. Manjunatha, D.K. Ravishankar et al.

Methods and Objects of Chemical Analysis • 2019

<jats:p>An electrogenerated Polyarginine modified carbon paste electrode (PAMCPE) was fabricated through a simple electropolymerization procedure. The devised electrode was characterized by cyclic voltammetry (CV) and Field Emission Scanning Electron Microscopy (FESEM). This electrode was utilized for electrocatalytic estimation of Riboflavin (RF) and its instantaneous resolution with ascorbic acid (AA) and folic acid (FA) in phosphate buffer solution (PBS) of pH 6.0 by differential pulse voltammetry (DPV). It was observed to be a very responsive electrode for the electrochemical detection and quantification of RF. It was revealed that PAMCPE generates higher current response towards RF contrast to the bare carbon paste electrode (BCPE). Under optimized condition, the RF oxidation current values were linearly reliant on the RF concentration increment with a limit of detection (LOD) of 9.3·10-8 M using DPV. The stable PAMCPE was effectively applied for estimation of RF in B-complex pill and complex human blood serum samples.</jats:p>

Samuel B. O. Adeloju, Fleurdelis Pablo

Electroanalysis • 1995

<jats:title>Abstract</jats:title><jats:p>The determination of ultratrace concentrations of molybdenum(<jats:sc>VI</jats:sc>) by adsorptive cathodic stripping voltammetry on a glassy carbon mercury film electrode is described. The method involves a controlled preconcentration of the element by interfacial accumulation as molybdenum‐8‐hydroxyquinoline (oxine) complex on the electrode followed by a cathodic stripping voltammetric measurement. The optimum analytical conditions for the measurement of molybdenum by this method include the use of 0.20 M acetate buffer at pH 5.25, 1 mM oxine, an accumulation potential of −0.40V (vs. Ag/AgCl) and a rotated electrode at 3000 rpm. Under these conditions, the linear concentration range and lowest detectable concentration obtained with a 5‐min accumulation were 0–300 μg L<jats:sup>−1</jats:sup> (<jats:italic>R</jats:italic><jats:sup>2</jats:sup> = 0.997) and 0.5 μg L<jats:sup>−1</jats:sup> [relative standard deviation (RSD) = 13.7%], respectively. The presence of most other metal ions do not interfere with the molybdenum determination, except for Pb<jats:sup>II</jats:sup> and Cd<jats:sup>II</jats:sup> which were successfully masked by addition of 3 μM EDTA, and Ti<jats:sup>IV</jats:sup> and W<jats:sup>VI</jats:sup> which were masked by 1 μM tartaric acid. The interference of surface‐active substances, such as Triton X‐100, is overcome by UV irradiation of the sample. The use of the adsorptive stripping voltammetric technique, after decomposition by dry ashing and UV treatment, is successfully demonstrated for the determination of molybdenum in biological and environmental materials.</jats:p>

Abdelrahman Nabile, Hassan Hendawy, Randa Abdel Salam et al.

• 0

<jats:p>A new green-validated and highly sensitive electrochemical method for the determination of molnupiavir (MOV) has been developed using cyclic voltammetry. The proposed analytical platform involves the use of disposable screen-printed reduced graphene oxide 2.5% electrode (SPrGOE 2.5%) for the first time to measure MOV with high specificity. The surface morphology of the sensor was investigated by using a scanning electron microscope armed with an energy-dispersive X-ray probe. The fabricated sensor attains improved sensitivity when sodium dodecyl sulfate (SDS) surfactant was added to the supporting electrolyte solution. Thus, various factors were investigated in order to select the best supporting electrolyte for voltammetric determination of MOV, and the optimum conditions were achieved by employing 0.04 M Britton-Robinson at pH 2, 10-4 M SDS, and SPrGOE 2.5%. Well-defined MOV oxidation peaks were obtained with no reduction peaks in cyclic voltammetry using diffusion-controlled pathways. The method was validated using differential pulse voltammetry according to ICH guidelines, providing it to be precise, accurate, specific, and robust with linearity over a concentration range of 50-6017 ng/mL. The incorporation of the reduced graphene nanoparticles supported the in situ interaction between electrode surface and MOV, improved the selectivity, and reduced the detection limit to the concentration level of 15.98 ng/mL. The stability investigation demonstrated that SPrGOE 2.5% can provide high-stability behavior throughout a three-month period under refrigeration. The fabricated SPrGOE 2.5% was successfully employed for the measurement of MOV in pharmaceutical capsules and human bio-fluids without the interference of endogenous matrix components as well as the commonly used excipient.</jats:p>

M. Arvand, M. Ghasempour Shiraz

Electroanalysis • 2012

<jats:title>Abstract</jats:title><jats:p>A carbon ionic liquid electrode modified in situ with sodium dodecylsulfate (SDS) was developed for the determination of clozapine (CLZ). These studies revealed that the oxidation of CLZ is facilitated at an in situ surfactant‐modified carbon ionic liquid electrode (ISS‐CILE). After optimization of analytical conditions, the peak currents for CLZ were found to vary linearly with its concentrations in the range of 1×10<jats:sup>−9</jats:sup>–1×10<jats:sup>−7</jats:sup> mol L<jats:sup>−1</jats:sup> with a slope of 2.18 µA/µmol L<jats:sup>−1</jats:sup>. The <jats:italic>LOD</jats:italic> and <jats:italic>LOQ</jats:italic> of the electrode were 2.08×10<jats:sup>−10</jats:sup> mol L<jats:sup>−1</jats:sup> and 6.95×10<jats:sup>−10</jats:sup> mol L<jats:sup>−1</jats:sup>, respectively. The proposed method was employed for the determination of CLZ in pharmaceutical formulations, blood serum and plasma samples without any pretreatment steps.</jats:p>

Khang Huynh, Bharathkiran Maddipudi, Rajesh Shende

Nanomaterials • 0

<jats:p>Asymmetric supercapacitors (ASCs) with two dissimilar electrodes are known to exhibit relatively moderate energy and power densities. If electrodes derived from earth-abundant materials or renewable resources such as lignocellulosic biomass (LCB) are used for fabrication, energy storage systems are expected to become less expensive and more sustainable. Hybrid electrode materials have advantages such as higher surface area, better chemical stability, and superior energy density. This study reports on the synthesis of a novel hybrid electrode material containing porous carbon (POC) and copper ferrite, which is designated as POC@Cu-ferrite, and its electrochemical performance in ASC configuration. Corn stover derived hydrochar is utilized for the sol–gel synthesis of POC@Cu-ferrite hybrid material using earth-abundant Cu and Fe-based precursors. This material is characterized using X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET) surface area analyzer, and scanning and transmission electron microscopy (SEM/TEM). As-synthesized Cu-ferrite is found to contain 89.2% CuFe2O4 and 10.8% Fe2O3, whereas other phases such as Fe3O4, CuFeO2, and CuO are observed for the POC@Cu-ferrite. BET-specific surface area (SSA) and pore volume of POC@Cu-ferrite are observed as 1068 m2/g and 0.72 cm3/g, respectively. POC@Cu-ferrite hybrid electrode is used with POC opposite electrode to fabricate ASC, which is tested using Gamry G-300 potentiostat/galvanostat/ZRA to obtain cyclic voltammetry (CV) profiles and galvanostatic charge–discharge (GCD) plots. ASC is also prepared using Cu-ferrite and POC materials and its specific capacitance and stability are compared with ASCs prepared with POC@Cu-ferrite and POC or graphene nanoplatelets (GNPs) electrodes. POC@Cu-ferrite hybrid electrode is found to be superior with a 2-fold higher capacitance and significant electrochemical stability over 100 GCD cycles as compared to the Cu-ferrite electrode.</jats:p>

Josip Radić, Maša Buljac, Boštjan Genorio et al.

Sensors • 0

<jats:p>A novel promising carbon paste electrode with excellent potentiometric properties was prepared for the analysis of trihexyphenidyl hydrochloride (THP), the acetylcholine receptor and an anticholinergic drug in real samples. It contains 10.2% trihexyphenidy-tetraphenylborate ionic pair as the electroactive material, with the addition of 3.9% reduced graphene oxide and 0.3% of anionic additive into the paste, which consists of 45.0% dibutylphthalate as the solvent mediator and 40.6% graphite. Under the optimized experimental conditions, the electrode showed a Nernstian slope of 58.9 ± 0.2 mV/decade with a regression coefficient of 0.9992. It exhibited high selectivity and reproducibility as well as a fast and linear dynamic response range from 4.0 × 10−7 to 1.0 × 10−2 M. The electrode remained usable for up to 19 days. Analytical applications showed excellent recoveries ranging from 96.8 to 101.7%, LOD was 2.5 × 10−7 M. The electrode was successfully used for THP analysis of pharmaceutical and biological samples.</jats:p>

Rabeay Y. A. Hassan, Maha A. Sultan, Maha M. Abou El‐Alamin et al.

Electroanalysis • 2017

<jats:title>Abstract</jats:title><jats:p>For the first time, the use of carbon nanotubes was exploited for the development of a sensitive electrochemical method for determination of the newly antifungal posaconazole (POS). The electrochemical activity of POS was investigated at the surface of multi‐walled nanotubes (MWNTs) modified electrode. The cyclic voltammograms showed a sharp oxidation peak at potential around 671 mV vs. Ag/AgCl. To reach the assay optimization, factors affecting the method sensitivity have been investigated, such as types of carbon nanotubes and its concentration in the electrode matrix, type of supporting electrolyte, pH, accumulation time and scan rate. A good linear relationship was obtained within the concentration range from 32–1280 ng/ml with the limit of detection and quantification of 11 ng/ml and 33 ng/ml, respectively. The proposed method was successfully applied for the determination of POS in its commercial dosage form, spiked human plasma samples, and dried blood spots. The in vivo results obtained were also used to study the pharmacokinetics of POS in human plasma. The results obtained were validated and found to be in accordance with those obtained by the reference methods.</jats:p>

L Bartalits, G Nagy, E Pungor

Clinical Chemistry • 1984

<jats:title>Abstract</jats:title> <jats:p>This amperometric technique for the determination of enzyme activity is based on detecting a decrease in the concentration of the NADH co-factor of the enzyme reaction. A glassy carbon electrode, modified by adsorption of Mg2+ and NADH, is used to measure the anodic peak current that corresponds to the oxidation of NADH. We found no significant difference between the enzyme activity of lactate dehydrogenase (E.C.1.1.1.27) preparations as measured by the above amperometric technique and by a spectrophotometric method.</jats:p>

D. J. Daly, C. K. O'Sullivan, G. G. Guilbault

Biochemical Society Transactions • 2000

<jats:p>The use of electrochemically grown polymers has expanded dramatically in the last couple of years, and they are now well established as membranes for immobilizing components. The evidence here for their anti-fouling properties is good. The poly(1,3-diaminobenzene)-covered electrodes performed well in the buffer, urine, plasma and serum samples, but not so well in the blood. The Ru/Rh/Pt, Rh/Rh and the Pt-on-glassy carbon electrodes covered with poly(1,3-diaminobenzene) were the best electrodes in the blood. The Pt disc seemed to exhibit the largest irrepeatability in most of the biological matrices.</jats:p>

Lin Zhang, Neus Vilà, Alain Walcarius et al.

ChemElectroChem • 2018

<jats:title>Abstract</jats:title><jats:p>A generic approach has been developed for sequential heterogeneous surface modification of electrodes. The strategy, which is applicable for a wide range of functional groups, involves two main steps. In the first one, azide‐alkene bifunctionalized electrodes are obtained by electrochemical reduction of a mixture of diazonium salts generated in situ from the corresponding 4‐azidoaniline and 4‐vinylaniline. In that way, we provide reactive sites that are available for further selective functionalization in a sequential process based on ‘click reactions’, in which subsequent immobilization of the targeted molecules is achieved by the azide‐alkyne cycloaddition Huisgen reaction and alkene‐thiol coupling. Feasibility of the method has been first demonstrated for the coimmobilization of two distinct redox moieties (cobaltocenium and ferrocene) as evidenced by cyclic voltammetry and X‐ray photoelectron spectroscopy measurements. The versatility of the sequential method has then been exploited for the coimmobilization of a molecular electrocatalyst [Cp*Rh(bpy) Cl]<jats:sup>+</jats:sup> and a biological catalyst, a NAD‐dependent dehydrogenase, that were proved to act in cascade in the electroenzymatic reduction of D‐fructose to D‐sorbitol. Such simple combination of diazonium chemistry and robust chemical reactions (‘click chemistry’) is promising for the environmentally friendly heterogeneous modification of electrodes with multiple chemical and biological catalysts.</jats:p>

Fahimeh Jalali, Amir M. Ashrafi, Davood Nematollahi

Electroanalysis • 2009

<jats:title>Abstract</jats:title><jats:p>A modified carbon paste electrode was constructed for the determination of dissolved oxygen using diamino‐<jats:italic>o</jats:italic>‐benzoquinone (DABQ) as the modifier. The electrochemical behavior of the electrode in citrate buffer (pH 2.0) was studied. In the presence of dissolved oxygen (DO) both cathodic and anodic peak currents decreased, indicating a chemical reaction between modifier and O<jats:sub>2</jats:sub>. The decrease in peak current was linearly proportional to the amount of dissolved oxygen in the concentration range of 252–1260 μM of DO. The electrode was utilized in the determination of DO in urine samples. The relative error and <jats:italic>RSD</jats:italic> of the method were 1.6% and 4.1%, respectively. The electrode was applied more than two months for the determination of DO without any significant divergence in its voltammetric response.</jats:p>

Yuvarajgouda Patil, Manjunath Megalamani, Jyothi Abbar et al.

ECS Advances • 2024

<jats:p>The electrochemical performance of phenylbutazone (PBZ) was studied using a multi-walled carbon-nanotube-modified paste electrode (MWCNT/CPE) using a variety of voltammetric tools like cyclic voltammetry (CV), linear sweep voltammetry (LSV), and square wave voltammetry (SWV). The results showed that the MWCNT/CPE exhibited remarkable electro-catalytic action towards the electrochemical oxidation of PBZ in a phosphate buffer solution of physiological pH 7 compared to a bare carbon paste electrode. The electro-kinetic parameters like heterogeneous rate constant, transfer coefficient, scan rate, pH, and involvement of electrons in electro-oxidation of PBZ was investigated. For bare CPE, the peak current was noted to be 19.53 <jats:italic>μ</jats:italic>A with peak potential of 0.6871 V. For MWCNT/CPE, the peak current was 30.53 <jats:italic>μ</jats:italic>A with peak potential of 0.6792 V. The anodic peak was analyzed, and the process was diffusion controlled. For the estimation of PBZ, a SWV technique was developed with great precision and accuracy, with a detection limit of 5.2 nM and a limit of quantification of 17 nM, in the concentration range 1 × 10<jats:sup>−7</jats:sup> to 10 × 10<jats:sup>−6</jats:sup> M. The MWCNT/CPE has been used successfully for PBZ detection in injection, blood, and urine samples, with recovery rates of 98.9% to 101.5%, 96.3% to101.7% and 98.3% to 102.8%, respectively.</jats:p> <jats:p> <jats:inline-formula> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ecsaad43ff-ga.jpg" xlink:type="simple"/> </jats:inline-formula> </jats:p>

Vera Bocharova, Evgeny Katz

The Chemical Record • 2012

<jats:title>Abstract</jats:title><jats:p>Electrode interfaces functionalized with various signal‐responsive materials have been designed to allow switchable properties of the modified electrodes. External signals of different nature (electrical potential, magnetic field, light, chemical/biochemical inputs) were applied to reversibly activate–deactivate the electrode interfaces upon demand. Multifunctional properties of the modified interfaces have allowed their responses to complex combinations of external signals. Further increase of their complexity has been achieved by integrating the signal‐responsive interfaces with unconventional biomolecular computing systems logically processing multiple biochemical signals. This approach has resulted in electrochemical systems controlled by complex variations of biomarkers corresponding to different physiological conditions, thus allowing biological control over electronic systems. The switchable electrodes have been integrated with various “smart” biosensing and signal‐processing systems and have been used to assemble biofuel cells producing power on demand. <jats:bold>DOI 10.1002/tcr.201100025</jats:bold></jats:p>

A. Heduit, D. R. Thevenot

Water Science and Technology • 1992

<jats:p>The zero current potential of a platinum electrode in a biological medium (wastewater, activated sludge) is strongly dependent on the surface characteristics of the metal. It is also influenced by pH (probably Pt/PtO system), dissolved oxygen (O2/OH- system), and ionic forms of nitrogen (NO2-/NH4+ and NO3-/NO2-systems).</jats:p> <jats:p>The experimental values of the coefficients relating the stabilized potential of a platinum electrode to the logarithm of the concentration of the elements under consideration (Nernst equations) are significantly different from the thermodynamic coefficients corresponding to each reaction. The platinum is thus not in equilibrium with the dissolved redox reactants and is likely subject to mixed potentials in which the adsorbed components play an important role.</jats:p>

Krishnaveni Venkidusamy, M. Megharaj

Frontiers in Microbiology • 2016

Electrode respiring bacteria (ERB) possess a great potential for many biotechnological applications such as microbial electrochemical remediation systems (MERS) because of their exoelectrogenic capabilities to degrade xenobiotic pollutants. Very few ERB have been isolated from MERS, those exhibited a bioremediation potential toward organic contaminants. Here we report once such bacterial strain, Stenotrophomonas maltophilia MK2, a facultative anaerobic bacterium isolated from a hydrocarbon fed MERS, showed a potent hydrocarbonoclastic behavior under aerobic and anaerobic environments. Distinct properties of the strain MK2 were anaerobic fermentation of the amino acids, electrode respiration, anaerobic nitrate reduction and the ability to metabolize n-alkane components (C8–C36) of petroleum hydrocarbons (PH) including the biomarkers, pristine and phytane. The characteristic of diazoic dye decolorization was used as a criterion for pre-screening the possible electrochemically active microbial candidates. Bioelectricity generation with concomitant dye decolorization in MERS showed that the strain is electrochemically active. In acetate fed microbial fuel cells (MFCs), maximum current density of 273 ± 8 mA/m2 (1000 Ω) was produced (power density 113 ± 7 mW/m2) by strain MK2 with a coulombic efficiency of 34.8%. Further, the presence of possible alkane hydroxylase genes (alkB and rubA) in the strain MK2 indicated that the genes involved in hydrocarbon degradation are of diverse origin. Such observations demonstrated the potential of facultative hydrocarbon degradation in contaminated environments. Identification of such a novel petrochemical hydrocarbon degrading ERB is likely to offer a new route to the sustainable bioremedial process of source zone contamination with simultaneous energy generation through MERS.

Rong Liu, Lina Ma, Shu-Chen Huang et al.

The Journal of Physical Chemistry C • 2016

Flexible energy storage devices require a simple, scalable and general strategy for fabricating high electrochemical performance and mechanically tough flexible electrodes. Herein, sustainable and biological bacterial cellulose (BC) is developed as substrate for Co3O4/graphene (GN), which permits high flexibility (suitable for bending angle of 180°), excellent tensile strength of 63 MPa, good wettability, and especially large mass loading of 9.61 mg cm–2 for a flexible and free-standing supercapacitor electrode. The Co3O4/GN/BC hybrid electrode exhibits both appreciable areal capacitance of 12.25 F cm–2 and gravimetric capacitance of 1274.2 F g–1. Moreover, the remarkable cycling stability with 96.4% capacitance retention after 20000 can be achieved. This study provides a facile procedure to improve the electrochemical performance and mechanical property of flexible supercapacitor electrodes, which are promising candidates for the application of a flexible power source.

N. Zhang, Lina Yue, Yajie Xie et al.

IEEE Journal of Translational Engineering in Health and Medicine • 2018

We propose a flexible, dry, and antibacterial electrode with a low and stable skin electrode contact impedance for bio-potential signal monitoring. We fabricated a bacterial cellulose/polyaniline/AgNO3 nanocomposite membrane (BC/PANI/AgNO3) and used it for bio-potential signal monitoring. The bacterial cellulose (BC) provides a 3-D nanoporous network structure, and it was used as a substrate material in the BC/PANI/AgNO3 nanocomposite membrane. Polyaniline (PANI) and AgNO3, acting as conductive and antibacterial components, respectively, were polymerized and deposited on the surfaces of BC nanofibers to produce uniform thin film membrane with flexible, antibacterial, and conductive properties. Various measurements were conducted, in terms of antibacterial activity, skin electrode contact impedance, and qualitative analysis of ECG signal recordings. The BC/PANI/AgNO3 membrane revealed 100% antibacterial activities against both the Staphylococcus aureus and Escherichia coli bacteria. The skin electrode contact impedance of the proposed BC/PANI/AgNO3 electrode is lower than that of the Ag/AgCl gel electrode, with the same active area. In addition, the electrocardiogram (ECG) signals acquired with the proposed electrodes have stable characteristic waveforms, and they are not contaminated by noise. The waveform fidelity of the BC/PANI/AgNO3 membrane electrodes over 800 ECG cardiac cycles is 99.49%, and after the electrodes were worn for 24 hours, a fidelity of 98.40% was recorded over the same number of cardiac cycles. With the low and stable skin electrode contact impedance, the proposed dry BC/PANI/AgNO3 membrane electrode provided high fidelity for ECG signal recordings, thus offering a potential approach for bio-potential signal monitoring. With the above benefits, the novel flexible and dry BC/PANI/AgNO3 electrode has a significant antibacterial. Most of all, it is the first research to develop antibacterial in the electrode design.

I. Hwang, Jongku Jeong, Taesuk You et al.

Biotechnology &amp; Biotechnological Equipment • 2018

ABSTRACT The present study used water-electrode plasma discharge to increase the effect of bacterial inactivation in water for bioengineering and biotechnological applications. The water-electrode plasma discharge system was fabricated using a newly designed plasma generator and a high-voltage power supply. Water contaminated with Escherichia coli was treated with water-electrode plasma discharge for 0, 1, 2, 3, 4, 5, 10, 20 and 30 min. As a result, the colony-forming units (cfu) of E. coli were reduced with plasma treatment time, reaching nearly complete inactivation after 30 min. In addition, rapid generation of H2O2 in the contaminated water was observed, which could mainly account for the effective bacterial inactivation. In conclusion, direct generation of reactive chemical species under water was successfully achieved by using a water-electrode plasma discharge system, which could be practically used to enhance bacterial inactivation in a variety of bioengineering applications.