YH Yau, MA Streicher

Galvanic Corrosion • 1988

<jats:p>The effect on corrosion of composition and microstructure in a series of Fe-Cr-10% Ni alloys with increasing chromium content has been investigated in reducing acids. In the range of 25 to 35% chromium there is a wide variation in the relative amounts of ferrite and austenite. In reducing acids (H2SO4 and HCl) there is preferential attack on the ferrite phases. However, the rate of attack on ferrite is considerably greater than expected on the basis of its chromium and nickel contents alone. This is because corrosion on the ferrite phase is significantly increased by galvanic action with the austenite in the microstructure. This galvanic effect is a function of the relative surface areas of the ferrite (anode) and the austenite (cathode).</jats:p> <jats:p>Previous investigators have derived equations for the effect of relative surface areas of anodes and cathodes on galvanic corrosion of two dissimilar metals in the form of parallel sheets of constant composition. However, in the alloys of this investigation there are simultaneous changes, not only in the areas of ferrite and austenite, but also in the compositions of these two phases. In the analysis of the data on the Fe-Cr-10% Ni alloys, the mathematical treatment developed for relative areas with constant compositions has been used to separate this factor from that of the varying composition of ferrite and austenite. The results may contribute to an understanding of the action of duplex microstructures in castings, weldmetal, and duplex stainless steels when these are exposed to reducing acids during pickling and plant service.</jats:p>

Qi Zhang, Zheng Liang, Xiaotao Guan et al.

Frontiers in Environmental Science • 0

<jats:p>The application of iron–carbon microbial cell activated sludge (ICMC-AS) was carried out in a membrane bioreactor (MBR) processor to treat wastewater from an integrated railway station. Results showed that the chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies of the original MBR processor increased from 80%, 30%, and 10% to 92%, 93.5%, and 92%, respectively. Further research showed that the combined sewage treatment system also had a strong impact resistance ability. The combined sewage treatment system ran stably when the COD, TN, and TP concentrations changed greatly. The in-depth analysis of the reaction process and reaction rate of the combined sewage treatment system revealed that the combined system is dominated by COD removal with high nitrogen removal efficiency. The removal rate constants of various pollutants were in the order: <jats:italic>K</jats:italic><jats:sub>COD</jats:sub> (0.647 ± 0.017) &amp;gt; <jats:inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:msub><mml:mi mathvariant="bold-italic">K</mml:mi><mml:mrow><mml:mi mathvariant="bold">N</mml:mi><mml:msubsup><mml:mi mathvariant="bold">O</mml:mi><mml:mn mathvariant="bold">3</mml:mn><mml:mo>−</mml:mo></mml:msubsup><mml:mo>−</mml:mo><mml:mi mathvariant="bold">N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></jats:inline-formula> (0.416 ± 0.044) &amp;gt; <jats:inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m2"><mml:mrow><mml:msub><mml:mi mathvariant="bold-italic">K</mml:mi><mml:mrow><mml:mi mathvariant="bold">N</mml:mi><mml:msubsup><mml:mi mathvariant="bold">H</mml:mi><mml:mn mathvariant="bold">4</mml:mn><mml:mo>+</mml:mo></mml:msubsup><mml:mo>−</mml:mo><mml:mi mathvariant="bold">N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></jats:inline-formula> (0.275 ± 0.014) &amp;gt; <jats:italic>K</jats:italic><jats:sub>TN</jats:sub> (0.258 ± 0.083). Calculations of the energy saving and carbon emission reduction of the combined system showed that the system’s annual carbon emission reduction could reach more than 388,203.55 kg CO<jats:sub>2</jats:sub>e, which remarkably improves the carbon emission reduction effect and obtains a good green effect. The results indicate that adding ICMC-AS to the MBR processor for combined wastewater treatment can substantially improve the efficiency of wastewater treatment and obtain better energy-saving and emission-reducing effects. This combined application provides an effective way for the transformation and upgrading of small- and medium-scale water treatment systems.</jats:p>

Humberto Garcia-Arellano, Miguel Alcalde, Antonio Ballesteros

Microbial Cell Factories • 0

<jats:title>Abstract</jats:title><jats:p>Industrial development may result in the increase of environmental risks. The enzymatic transformation of polluting compounds to less toxic or even innocuous products is an alternative to their complete removal. In this regard, a number of different redox enzymes are able to transform a wide variety of toxic pollutants, such as polynuclear aromatic hydrocarbons, phenols, azo dyes, heavy metals, etc. Here, novel information on chromate reductases, enzymes that carry out the reduction of highly toxic Cr(VI) to the less toxic insoluble Cr(III), is discussed. In addition, the properties and application of bacterial and eukaryotic proteins (lignin-modifying enzymes, peroxidases and cytochromes) useful in environmental enzymology is also discussed.</jats:p>

Kenneth H. Williams, Susan S. Hubbard, Jillian F. Banfield

Journal of Geophysical Research: Biogeosciences • 2007

<jats:p>We have evaluated the usefulness of the self‐potential (SP) geophysical method to track the onset and location of microbial sulfate‐reduction in saturated sediments during organic carbon amendment. Following stimulation of sulfate‐reducing bacteria (SRB) by addition of lactate, anomalous voltages exceeding 600 mV correlated in space and time with the accumulation of dissolved sulfide. Abiotic experiments in which the sulfide concentration at the measurement electrode was systematically varied showed a positive correlation between the magnitude of the SP anomaly and differences in the half‐cell potential associated with the measurement and reference electrodes. Thus, we infer that the SP anomalies resulted from electrochemical differences that developed between sulfide‐rich regions and areas having higher oxidation potential. In neither experiment did generation of an SP anomaly require the presence of an in situ electronic conductor, as is required by other models. These findings emphasize the importance of incorporation of electrochemical effects at electrode surfaces in interpretation of SP data from geophysical studies. We conclude that SP measurements provide a minimally invasive means for monitoring stimulated sulfate‐reduction within saturated sediments.</jats:p>

GA Gehring

Galvanic Corrosion • 1988

<jats:p>The use of dissimilar metal construction in power plant condensers is a common practice. It is not unusual to encounter condensers fabricated with stainless steel or titanium tubes, copper alloy tubesheets, and cast iron or carbon steel waterboxes. Furthermore, condensers initially furnished with copper alloy tubes and copper alloy tubesheets are frequently being retubed with stainless steel or titanium tubes. In several instances, the use of dissimilar alloys in power plant condensers has led to severe galvanic corrosion, particularly of the tubesheet.</jats:p> <jats:p>The primary factors affecting galvanic corrosion in a condenser include the electrochemical characteristics (that is, potential and polarization) of the different alloys, the effective area relationships of the different alloys, and the specific characteristics of the cooling water (for example, conductivity, temperature, and so forth). A number of studies have been conducted to develop a better understanding of the relative influence and the interrelationship of these various factors. These studies, conducted under simulated condenser flow conditions, have shown that (1) the length of tube involved in a tubesheet/tube galvanic cell can extend beyond 6 m down the tube, depending on the tube alloy and water salinity; (2) the use of either titanium or stainless steel tubes with a copper alloy tubesheet can result in significant galvanic corrosion of the tubesheet; (3) galvanically coupling a Muntz metal tubesheet to either stainless steel or titanium can cause severe dezincification of the tubesheet; (4) the intensity of galvanic attack will tend to diminish as the salinity of the cooling water decreases; (5) the intensity of the galvanic attack will tend to diminish as the cooling water temperature decreases; (6) certain copper alloy tubesheets may be galvanically compatible with either stainless steel or titanium tubes if the cooling water salinity or temperature is sufficiently low; (7) as a tubesheet alloy coupled to either stainless steel or titanium tubes, aluminum bronze (Alloy D) is significantly less susceptible to galvanic attack than Muntz metal; (8) cathodic protection properly implemented can effectively mitigate galvanic attack of copper alloy tubesheets caused by more noble alloy tubes, and (9) the cathodic protection current required to mitigate galvanic corrosion will be greater in higher salinity, higher temperature cooling water.</jats:p>

JW Oldfield

Galvanic Corrosion • 1988

<jats:p>Galvanic corrosion can be defined simply as that corrosion that occurs as a result of one metal being in electrical contact with another in a conducting corrosive environment. The corrosion is stimulated by the potential difference that exists between the two metals, the more noble material acting as a cathode where some oxidizing species is reduced, the more active metal, which corrodes, acting as the anode. To fully understand this process it is first necessary to understand the basic thermodynamics and kinetics of electrochemical reactions. These are considered with particular reference to exchange current densities and the factors that control them, linear and Tafel kinetics, concentration and mass transfer effects, and mixed potential theory. The practical side of galvanic corrosion and its relationship to electrochemical parameters is considered with particular reference to the most important cathodic processes, that is, oxygen reduction and hydrogen evolution, as they occur on engineering materials, for example, steel, stainless steel, copper base alloys, and so forth and to the general form of the anodic processes that occur. Finally the use of galvanic series as a predictive tool is discussed. In addition methods used to model galvanic situations with the aim of predicting corrosion are briefly mentioned and their advantages and limitations outlined.</jats:p>

Nurettin ÇEK

Turkish Journal of Engineering • 0

<jats:p xml:lang="en">Detection and control of galvanic corrosion is a critical aspect of engineering for the chemical processes used in the fabrication of metals, alloys and materials industry. Galvanic corrosion can occur when two metals having different status in the electrochemical ambient are configured in mutual interaction within the galvanic cell structure and are exposed to the ion conducting electrolyte. In this study, ion-containing water was used as an electrolyte, the zinc as the anode electrode, copper as the cathode was used as an electrode, and a galvanic cell was fabricated. The formation of corrosion products with time on zinc anode reduced the voltage and current in galvanic cell considerable and anode film layer of considerable increase. Time-dependent experiments have provided good sources of information about the performance of the zinc anode electrode and the copper cathode electrode in the galvanic cell. </jats:p>

Giacomo Spisni, Giulia Massaglia, Candido Fabrizio Pirri et al.

• 0

<jats:p>In this work, we describe the optimization of carbon-based electrodes employed in Bio-Electrochemical Systems (BES) by the deposition on commercial carbon paper electrodes of nanostructured layers of poly(3,4-ethylene-dioxy-thiophene) poly(styrene-sulfonate) (PEDOT:PSS) via Ultrasonic Spray Coating (USC). This innovative application of USC allowed us to demon-strate that uniform and controlled depositions of PEDOT:PSS can be successfully obtained on car-bon-based electrodes. We characterized the morphology and verified the spatial uniformity of depositions via scanning electron microscopy and Raman spectroscopy. Electrochemical charac-terizations on fabricated electrodes demonstrated a more than two-fold increase in electrochemi-cal active surface area with respect to bare carbon paper. A lab-scale experiments on BES was performed selecting Microbial Fuel Cells (MFCs) as the reference devices. Devices featuring USC-deposited PEDOT:PSS electrodes showed a three-fold higher Energy recovery with respect to con-trol cells, reaching a maximum value of (13 ± 2) J·m−3. Furthermore, the optimal PEDOT:PSS con-centration for the MFCs improvement is in line with the values reported in the literature for other deposition methods. In conclusion, this work demonstrates that USC is a promising technique for application in BES.</jats:p>

Kevin C. Honeychurch, Martina Piano

Biosensors • 0

<jats:p>In recent years, great progress has been made in the development of sensors and biosensors to meet the demands of environmental and food analysis. In this Special Issue, the state of art and the future trends in the field of environmental and food analyses have been explored. A total of seven papers (three research and four review papers) are included. These are focused on the fabrication and detection of contaminates such as heavy metals, pesticides and food components, including uric acid and 3-hydroxybutyrate. Included in this Issue is a paper dedicated to the experimental determination of the electroactive area of screen-printed electrodes, an important parameter in the development of such sensors.</jats:p>

Hemanth Kumar Tanneru, Resmi Suresh, Aravind Vyas Ramanan et al.

TECHNOLOGY • 2016

<jats:p> A simple first-principles mathematical model is developed to predict the performance of a micro photosynthetic power cell ([Formula: see text]PSC), an electrochemical device which generates electricity by harnessing electrons from photosynthesis in the presence of light. A lumped parameter approach is used to develop a model in which the electrochemical kinetic rate constants and diffusion effects are lumped into a single characteristic rate constant [Formula: see text]. A non-parametric estimation of [Formula: see text] for the [Formula: see text]PSC is performed by minimizing the sum square errors (SSE) between the experimental and model predicted current and voltages. The developed model is validated by comparing the model predicted [Formula: see text] characteristics with experimental data not used in the parameter estimation. Sensitivity analysis of the design parameters and the operational parameters reveal interesting insights for performance enhancement. Analysis of the model also suggests that there are two different operating regimes that are observed in this [Formula: see text]PSC. This modeling approach can be used in other designs of [Formula: see text]PSCs for performance enhancement studies. </jats:p>

Wassila Sefari, Ali Zazoua, Helim Rabiaa et al.

Journal of The Electrochemical Society • 2024

<jats:p>Bisphenol A is a widely used endocrine disruptor known for its toxicity and prevalence in the environment. It contaminates drinking water, especially when plastic bottles are exposed to Sunlight. Rapid, on-site detection of BPA in drinking water is crucial for protecting human health and the environment. Herein, we developed an electrochemical sensor for detecting and monitoring bisphenol A in water bodies utilizing biobased materials. The device uses a biopolymeric membrane with agarose and gelified green tea tannins (GT/Agar). A sensitive part was made using this natural composite due to its high ability to attach bisphenol A to tannin monomers. Green tea tannins were purified and characterized through HPLC, FTIR, SEM, and AFM. The electrochemical activity of the GT-Agar/Au sensor is also evaluated by electrochemical impedance spectroscopy, cyclic voltammetry, square wave voltammetry and scan rate. Based on its redox signal under the optimal experimental conditions, this sensor has a detection range of 10<jats:sup>−16 </jats:sup>M to 10<jats:sup>−4 </jats:sup>M, a limit of detection of 1.52 to 10<jats:sup>−17 </jats:sup>M and very high selectivity. The proposed sensor successfully determined BPA levels from ultra-trace concentrations in bottled water samples, achieving satisfactory recovery rates. Compared to the results obtained using HPLC, it demonstrates high reliability.</jats:p> <jats:p> <jats:inline-formula> </jats:inline-formula> </jats:p>

Amal Elleuch, Kamel Halouani, Yongdan Li

Energy Technology • 2019

<jats:title>Abstract</jats:title><jats:p>In this paper, we propose the first demonstration of the flexibility of operating directly Intermediate Temperature Solid Oxide Fuel Cell (IT‐SOFC) with liquid biofuels for sustainable clean power generation. Biofuel used in this part is prepared through an upgrading process of bio‐oil obtained from olive mill wastewater sludge detailed in part 1 and demonstrated a successful improvement in physicochemical properties. Cell electrochemical polarization behavior, stability and internal decomposition of upgraded bio‐oil over the Ni‐SDC anode at different operating conditions such as temperatures and feed flow rates were deeply investigated. Results showed that IT‐SOFC is able to convert the upgraded bio‐oil to electricity at viable power densities (230 mW cm<jats:sup>−2</jats:sup>at 750 °C) which is majorly related to the production of reactive fuels (H<jats:sub>2</jats:sub>, CO, CH<jats:sub>4</jats:sub>) from upgraded bio‐oil cracking over Ni‐based catalyst. Several side reactions may also occur over anode. Reverse Boudouard reaction is the main reaction reducing deposits as it forms. Bio‐oil upgrading leads to a promising stability with limited carbon deposits (1.35 wt %) at 750 °C.</jats:p>

Fiza Noor Zahara, J. Keshavayya, Chethan Krishnamurthy et al.

Luminescence • 2024

<jats:title>ABSTRACT</jats:title><jats:p>The fluorescent materials have sparked a lot of research interests due to their unique electronic, optical and chemical characteristics. Here, we are intended to present a simple and facile synthesis of novel orange emitting thiazole‐pyridone fluorescent tag (TPFT) by a simple diazo coupling reaction and the structural elucidation was carried out by IR, NMR (<jats:sup>1</jats:sup>H and <jats:sup>13</jats:sup>C), UV–Vis, photoluminescence and HR‐MS spectrometry. The solvatochromic behaviour of the TPFT offered crucial information about the formation of hydrazone and azo tautomeric forms. The DFT simulations are computed to calculate HOMO‐LUMO energy gap (3.028 eV) of TPFT along with MEP and RDG analyses. Comprehensive LFP visualization is revealed under both normal and UV light conditions (365 nm). The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to analyse the electrochemical behaviour of the TPFT‐modified glassy carbon electrode (MGCE) and exhibited a lower detection limit of 7.89 × 10<jats:sup>−8</jats:sup> M (S/<jats:italic>N</jats:italic> = 3) with a linear range of 0.5–8.0 μM for DA detection. The live‐cell imaging study of TPFT showed a strong blue emission at 453 nm, which generally indicates the existence of fluorescence stability.</jats:p>

Jana Klein, Siegfried R. Waldvogel

ChemSusChem • 2023

<jats:title>Abstract</jats:title><jats:p>A sustainable electrochemical pathway for degradation and thermal treatment of technical lignosulfonate is presented. This approach is an opportunity to produce remarkable quantities of low molecular weight compounds, such as vanillin and acetovanillone. For the electrochemical degradation, a simple two‐electrode arrangement in aqueous media is used, which is also easily scalable. The oxidation of the biopolymer occurs at the anode whereas hydrogen is evolved at the cathode. The subsequent thermal treatment supports the degradation of the robust chemical structure of lignosulfonates. With optimized electrolytic conditions, vanillin could be obtained in 9.7 wt% relative to the dry mass of lignosulfonate used. Aside from vanillin, by‐products such as acetovanillone or vanillic acid were observed in lower yields. A new and reliable one‐pot, two‐step degradation of different technically relevant lignosulfonates is established with the advantages of using electrons as an oxidizing agent, which results in low quantities of reagent waste.</jats:p>

Abanti Shama Afroz, Donato Romano, Francesco Inglese et al.

Applied Sciences • 0

<jats:p>Sustainable, green energy harvesting has gained a considerable amount of attention over the last few decades and within its vast field of resources, bio-energy harvesters have become promising. These bio-energy harvesters appear in a wide variety and function either by directly generating energy with mechanisms similar to living organisms or indirectly by extracting energy from living organisms. Presently this new generation of energy harvesters is fueling various low-power electronic devices while being extensively researched for large-scale applications. In this review we concentrate on recent progresses of the three promising bio-energy harvesters: microbial fuel cells, enzyme-based fuel cells and biomechanical energy harvesters. All three of these technologies are already extensively being used in small-scale applications. While microbial fuel cells hold immense potential in industrial-scale energy production, both enzyme-based fuel cells and biomechanical energy harvesters show promises of becoming independent and natural power sources for wearable and implantable devices for many living organisms including humans. Herein, we summarize the basic principles of these bio-energy harvesting technologies, outline their recent advancements and estimate the near future research trends.</jats:p>

Amro Hassanein, Freddy Witarsa, Stephanie Lansing et al.

Sustainability • 0

<jats:p>Anaerobic digestion (AD) is a biological-based technology that generates methane-enriched biogas. A microbial electrolysis cell (MEC) uses electricity to initiate bacterial oxidization of organic matter to produce hydrogen. This study determined the effect of energy production and waste treatment when using dairy manure in a combined AD and MEC (AD-MEC) system compared to AD without MEC (AD-only). In the AD-MEC system, a single chamber MEC (150 mL) was placed inside a 10 L digester on day 20 of the digestion process and run for 272 h (11 days) to determine residual treatment and energy capacity with an MEC included. Cumulative H2 and CH4 production in the AD-MEC (2.43 L H2 and 23.6 L CH4) was higher than AD-only (0.00 L H2 and 10.9 L CH4). Hydrogen concentration during the first 24 h of MEC introduction constituted 20% of the produced biogas, after which time the H2 decreased as the CH4 concentration increased from 50% to 63%. The efficiency of electrical energy recovery (ηE) in the MEC was 73% (ηE min.) to 324% (ηE max.), with an average increase of 170% in total energy compared to AD-only. Chemical oxygen demand (COD) removal was higher in the AD-MEC (7.09 kJ/g COD removed) system compared to AD-only (6.19 kJ/g COD removed). This study showed that adding an MEC during the digestion process could increase overall energy production and organic removal from dairy manure.</jats:p>

Yaniv Shlosberg, Vera Brekhman, Tamar Lotan et al.

International Journal of Molecular Sciences • 0

<jats:p>In recent years, extensive efforts have been made to develop clean energy technologies to replace fossil fuels to assist the struggle against climate change. One approach is to exploit the ability of bacteria and photosynthetic organisms to conduct external electron transport for electricity production in bio-electrochemical cells. In this work, we first show that the sea anemones Nematostella vectensis and eggs of Artemia (brine shrimp) secrete redox-active molecules that can reduce the electron acceptor Cytochrome C. We applied 2D fluorescence spectroscopy and identified NADH or NADPH as secreted species. Finally, we broaden the scope of living organisms that can be integrated with a bio-electrochemical cell to the sea anemones group, showing for the first time that Nematostella and eggs of Artemia can produce electrical current when integrated into a bio-electrochemical cell.</jats:p>

Xin-Li Du, Zhenhua Zhang, Xiaodi Zheng et al.

Nature Communications • 2020

Epithelial-mesenchymal transition (EMT) is critically involved in a variety of biological processes. Electrochemical sensing offers potential to develop more effective technology for EMT detection. In this study, by using the unique performance of quantum dot (QD)-nanocomposite materials, we establish an electrochemical biosensor that can specifically detect the change of E-cadherin and analyze different stages of EMT. The signal for EMT is largely magnified due to the transmission of molecular information to the electronic device. In addition, differential pulse voltammetry reveals that the response of the electrochemical signals is rapid and sensitive, due to the synergistic effect of QDs and carbon nanotube-gold nanoparticles. Our study thus suggests that electrochemical sensing is an effective technology for detecting EMT and may have broad applications in analyzing various cell type transitions. Epithelial-mesenchymal transition (EMT) plays a key role in embryonic development, wound healing and cancer. Here the authors develop an electrochemical sensor to detect EMT using E-cadherin antibody-quantum dot conjugates and a carbon nanotube-gold nanoparticle-modified electrode as a detection platform.

Wenhui Ji, Xiao Tang, Wei Du et al.

Chemical Society Reviews • 2021

This review highlights the biological importance of mitochondrial energy metabolism and the applications of multiple optical/electrochemical approaches to determine energy metabolites. Mitochondria, the main sites of oxidative phosphorylation and adenosine triphosphate (ATP) biosynthesis, provide the majority of energy required by aerobic cells for maintaining their physiological activity. They also participate in cell growth, differentiation, information transmission, and apoptosis. Multiple mitochondrial diseases, caused by internal or external factors, including oxidative stress, intense fluctuations of the ionic concentration, abnormal oxidative phosphorylation, changes in electron transport chain complex enzymes and mutations in mitochondrial DNA, can occur during mitochondrial energy metabolism. Therefore, developing accurate, sensitive, and specific methods for the in vivo and in vitro detection of mitochondrial energy metabolites is of great importance. In this review, we summarise the mitochondrial structure, functions, and crucial energy metabolic signalling pathways. The mechanism and applications of different optical/electrochemical methods are thoroughly reviewed. Finally, future research directions and challenges are proposed.

Tailin Xu, Nikki Scafa, Li‐Ping Xu et al.

Electroanalysis • 2014

Nitric oxide (NO) plays an important role in physiological processes and it has been confirmed some human diseases are related to its biological function. Electrochemical sensors provide an efficient way to explore the NO function in biological processes. This review details different kinds of electrochemical sensors used for NO concentration detection between 2008 and 2013 together with their application in biological samples. Four commonly used electrodes and different assisted analysis membranes used for contributions towards the development of the novel sensors were summarized. Electrochemical sensors employed to measure NO concentration in a single cell, cell culture, tissue homogenate, organ, in vivo, human being, as well as in plant were also detailed. The trends of developing novel NO sensors were outlooked in the last part.

N. Ktari, P. Poncet, H. Sénéchal et al.

Langmuir • 2010

Polystyrene surfaces may be patterned by Ag(II), NO(3)(•), and OH(•) electrogenerated at the tip of a scanning electrochemical microscope. These electrogenerated reagents lead to local surface oxidation of the polymer. The most efficient surface treatment is obtained with Ag(II). The patterns are evidenced by XPS and IR and also by the surface wettability contrast between the hydrophobic virgin surface and the hydrophilic pattern. Such Ag(II) treatment of a polystyrene Petri dish generates discriminative surfaces able to promote or disfavor the adhesion of proteins and also the adhesion and growth of adherent cells. The process is also successfully applied to a cyclo-olefin copolymer and should be suitable to pattern any hydrogenated polymer.

Jun Wang, Chengxiong Wu, N. Hu et al.

Biosensors • 2012

Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology.

Yuan Li, Chao Yu

Journal of Nanomaterials • 2016

A novel nanointerface of graphene oxide-doped polypyrrole (GO/PPy) is prepared on the surface of an indium tin oxide (ITO) electrode for electrochemical impedance detection of cell adhesion and proliferation through a facile one-step electropolymerization. The prepared GO/PPy nanocomposite had a robust surface and provided a biocompatible substrate for A549 cells adhesion and proliferation. The adhesion and proliferation of A549 cells on the surface of the GO/PPy modified ITO electrode directly increased the electron transfer resistance of [Fe(CN)6]3−/4− redox probe and influenced the impedance properties of the GO/PPy modified ITO electrode system. Based on these results, the adhesion and proliferation of A549 cells could be detected by electrochemical impedance technology using two approaches. Therefore, the present paper confirms that the GO/PPy nanocomposite film provides an excellent biological-electrical interface for cell immobilization and offers advantages of simple, low-cost fabrication and multiparameter detection and possesses potential application in cytological studies.

Li-Ping Yan, Ming-Yong Wen, Yu Qin et al.

Angewandte Chemie International Edition • 2022

Many cells in vivo have their inherent motions, which involve numerous biochemical and biophysical signals synergistically regulating cell behaviors and functions. However, existing methods offer little information about the concurrently chemical and physical responses of dynamically pulsing cells. Here, we report a soft electrode with electrospun poly(3,4-ethylenedioxythiophene) (PEDOT)-based nanomesh to fully comply with spontaneous motions of cells. Moreover, this electrode demonstrated excellent electrical conductivity, electrochemical performance and cellular biocompatibility. Cardiomyocytes cultured thereon exhibited autonomous and rhythmic contractility, and synchronously induced mechanical deformation of the underlying electrode, which allowed real-time monitoring of nitric oxide release and electrophysiological activity of cardiomyocytes. This work provides a promising way toward recording chemical and electrical signals of biological systems with their natural motions.

L. Fritea, F. Bǎnicǎ, T. Costea et al.

Materials • 2021

Monitoring human health for early detection of disease conditions or health disorders is of major clinical importance for maintaining a healthy life. Sensors are small devices employed for qualitative and quantitative determination of various analytes by monitoring their properties using a certain transduction method. A “real-time” biosensor includes a biological recognition receptor (such as an antibody, enzyme, nucleic acid or whole cell) and a transducer to convert the biological binding event to a detectable signal, which is read out indicating both the presence and concentration of the analyte molecule. A wide range of specific analytes with biomedical significance at ultralow concentration can be sensitively detected. In nano(bio)sensors, nanoparticles (NPs) are incorporated into the (bio)sensor design by attachment to the suitably modified platforms. For this purpose, metal nanoparticles have many advantageous properties making them useful in the transducer component of the (bio)sensors. Gold, silver and platinum NPs have been the most popular ones, each form of these metallic NPs exhibiting special surface and interface features, which significantly improve the biocompatibility and transduction of the (bio)sensor compared to the same process in the absence of these NPs. This comprehensive review is focused on the main types of NPs used for electrochemical (bio)sensors design, especially screen-printed electrodes, with their specific medical application due to their improved analytical performances and miniaturized form. Other advantages such as supporting real-time decision and rapid manipulation are pointed out. A special attention is paid to carbon-based nanomaterials (especially carbon nanotubes and graphene), used by themselves or decorated with metal nanoparticles, with excellent features such as high surface area, excellent conductivity, effective catalytic properties and biocompatibility, which confer to these hybrid nanocomposites a wide biomedical applicability.

J. Rivnay, M. Ramuz, P. Leleux et al.

Applied Physics Letters • 2015

Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal.

F. Mariani, I. Gualandi, W. Schuhmann et al.

Microchimica Acta • 2022

Electrode miniaturization has profoundly revolutionized the field of electrochemical sensing, opening up unprecedented opportunities for probing biological events with a high spatial and temporal resolution, integrating electrochemical systems with microfluidics, and designing arrays for multiplexed sensing. Several technological issues posed by the desire for downsizing have been addressed so far, leading to micrometric and nanometric sensing systems with different degrees of maturity. However, there is still an endless margin for researchers to improve current strategies and cope with demanding sensing fields, such as lab-on-a-chip devices and multi-array sensors, brain chemistry, and cell monitoring. In this review, we present current trends in the design of micro-/nano-electrochemical sensors and cutting-edge applications reported in the last 10 years. Micro- and nanosensors are divided into four categories depending on the transduction mechanism, e.g., amperometric, impedimetric, potentiometric, and transistor-based, to best guide the reader through the different detection strategies and highlight major advancements as well as still unaddressed demands in electrochemical sensing.

S. Lakard, Ileana‐Alexandra Pavel, B. Lakard

Biosensors • 2021

Neurotransmitters are biochemical molecules that transmit a signal from a neuron across the synapse to a target cell, thus being essential to the function of the central and peripheral nervous system. Dopamine is one of the most important catecholamine neurotransmitters since it is involved in many functions of the human central nervous system, including motor control, reward, or reinforcement. It is of utmost importance to quantify the amount of dopamine since abnormal levels can cause a variety of medical and behavioral problems. For instance, Parkinson’s disease is partially caused by the death of dopamine-secreting neurons. To date, various methods have been developed to measure dopamine levels, and electrochemical biosensing seems to be the most viable due to its robustness, selectivity, sensitivity, and the possibility to achieve real-time measurements. Even if the electrochemical detection is not facile due to the presence of electroactive interfering species with similar redox potentials in real biological samples, numerous strategies have been employed to resolve this issue. The objective of this paper is to review the materials (metals and metal oxides, carbon materials, polymers) that are frequently used for the electrochemical biosensing of dopamine and point out their respective advantages and drawbacks. Different types of dopamine biosensors, including (micro)electrodes, biosensing platforms, or field-effect transistors, are also described.

Qianjin Chen, Kim McKelvey, M. Edwards et al.

The Journal of Physical Chemistry C • 2016

Ion transport near interfaces is a fundamental phenomenon of importance in electrochemical, biological, and colloidal systems. In particular, electric double layers in highly confined spaces have implications for ion transport in nanoporous energy storage materials. By exploiting redox cycling amplification in lithographically fabricated thin-layer electrochemical cells comprising two platinum electrodes separated by a distance of 150–450 nm, we observed current enhancement during cyclic voltammetry of the hexaamineruthenium(III) chloride redox couple (Ru(NH3)63/2+) at low supporting electrolyte concentrations, resulting from ion enrichment of Ru(NH3)63/2+ in the electrical double layers and an enhanced ion migration contribution to mass transport. The steady-state redox cycling was shown to decrease to predominately diffusion controlled level with increasing supporting electrolyte concentration. Through independent biasing of the potential on the individual Pt electrodes, the voltammetric transport limit...

M. Abarkan, A. Pirog, Donnie Mafilaza et al.

Advanced Science • 2022

Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS‐based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro‐organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single‐cell action potentials and multicellular slow potentials reflecting micro‐organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.

Chia-Fei Liu, Tzu-Hsin Lee, Jeng-fen Liu et al.

Scientific Reports • 2018

Ti-24Nb-4Zr-8Sn (Ti2448), a new β-type Ti alloy, consists of nontoxic elements and exhibits a low uniaxial tensile elastic modulus of approximately 45 GPa for biomedical implant applications. Nevertheless, the bio-corrosion resistance and biocompatibility of Ti2448 alloys must be improved for long-term clinical use. In this study, a rapid electrochemical anodization treatment was used on Ti2448 alloys to enhance the bio-corrosion resistance and bone cell responses by altering the surface characteristics. The proposed anodization process produces a unique hybrid oxide layer (thickness 50–120 nm) comprising a mesoporous outer section and a dense inner section. Experiment results show that the dense inner section enhances the bio-corrosion resistance. Moreover, the mesoporous surface topography, which is on a similar scale as various biological species, improves the wettability, protein adsorption, focal adhesion complex formation and bone cell differentiation. Outside-in signals can be triggered through the interaction of integrins with the mesoporous topography to form the focal adhesion complex and to further induce osteogenic differentiation pathway. These results demonstrate that the proposed electrochemical anodization process for Ti2448 alloys with a low uniaxial tensile elastic modulus has the potential for biomedical implant applications.

P. Ash, H. Reeve, J. Quinson et al.

Analytical Chemistry • 2016

We describe a method for addressing redox enzymes adsorbed on a carbon electrode using synchrotron infrared microspectroscopy combined with protein film electrochemistry. Redox enzymes have high turnover frequencies, typically 10–1000 s–1, and therefore, fast experimental triggers are needed in order to study subturnover kinetics and identify the involvement of transient species important to their catalytic mechanism. In an electrochemical experiment, this equates to the use of microelectrodes to lower the electrochemical cell constant and enable changes in potential to be applied very rapidly. We use a biological cofactor, flavin mononucleotide, to demonstrate the power of synchrotron infrared microspectroscopy relative to conventional infrared methods and show that vibrational spectra with good signal-to-noise ratios can be collected for adsorbed species with low surface coverages on microelectrodes with a geometric area of 25 × 25 μm2. We then demonstrate the applicability of synchrotron infrared microspectroscopy to adsorbed proteins by reporting potential-induced changes in the flavin mononucleotide active site of a flavoenzyme. The method we describe will allow time-resolved spectroscopic studies of chemical and structural changes at redox sites within a variety of proteins under precise electrochemical control.

B. Esteban‐Fernandez de Avila, E. Araque, S. Campuzano et al.

Analytical Chemistry • 2015

Novel disposable electrochemical DNA sensors were prepared for the detection of a target DNA sequence on the p53 tumor suppressor (TP53) gene. The electrochemical platform consisted of screen-printed carbon electrodes (SPCEs) functionalized with a water-soluble reduced graphene oxide-carboxymethylcellulose (rGO-CMC) hybrid nanomaterial. Two different configurations involving hairpin specific capture probes of different length covalently immobilized through carbodiimide chemistry on the surface of rGO-CMC-modified SPCEs were implemented and compared. Upon hybridization, a streptavidin-peroxidase (Strep-HRP) conjugate was employed as an electrochemical indicator. Hybridization was monitored by recording the amperometric responses measured at -0.10 V (vs an Ag pseudo-reference electrode) upon the addition of 3,3',5,5'-tetramethylbenzidine (TMB) as a redox mediator and H2O2 as an enzyme substrate. The implemented DNA platforms allow single nucleotide polymorphism (SNP) discrimination in cDNAs from human breast cancer cell lines, which makes such platforms excellent as new diagnosis tools in clinical analysis.

Hye Kyu Choi, Jin-Ha Choi, Jinho Yoon

Biosensors • 2023

Neurotransmitters are chemical compounds released by nerve cells, including neurons, astrocytes, and oligodendrocytes, that play an essential role in the transmission of signals in living organisms, particularly in the central nervous system, and they also perform roles in realizing the function and maintaining the state of each organ in the body. The dysregulation of neurotransmitters can cause neurological disorders. This highlights the significance of precise neurotransmitter monitoring to allow early diagnosis and treatment. This review provides a complete multidisciplinary examination of electrochemical biosensors integrating nanomaterials and nanotechnologies in order to achieve the accurate detection and monitoring of neurotransmitters. We introduce extensively researched neurotransmitters and their respective functions in biological beings. Subsequently, electrochemical biosensors are classified based on methodologies employed for direct detection, encompassing the recently documented cell-based electrochemical monitoring systems. These methods involve the detection of neurotransmitters in neuronal cells in vitro, the identification of neurotransmitters emitted by stem cells, and the in vivo monitoring of neurotransmitters. The incorporation of nanomaterials and nanotechnologies into electrochemical biosensors has the potential to assist in the timely detection and management of neurological disorders. This study provides significant insights for researchers and clinicians regarding precise neurotransmitter monitoring and its implications regarding numerous biological applications.

Jingjing Zhang, Junyu Zhou, Rongrong Pan et al.

ACS Sensors • 2018

Previous measurements of cell populations might obscure many important cellular differences, and new strategies for single-cell analyses are urgently needed to re-examine these fundamental biological principles for better diagnosis and treatment of diseases. Electrochemistry is a robust technique for the analysis of single living cells that has the advantages of minor interruption of cellular activity and provides the capability of high spatiotemporal resolution. The achievements of the past 30 years have revealed significant information about the exocytotic events of single cells to elucidate the mechanisms of cellular activity. Currently, the rapid developments of micro/nanofabrication and optoelectronic technologies drive the development of multifunctional electrodes and novel electrochemical approaches with higher resolution for single cells. In this Perspective, three new frontiers in this field, namely, electrochemical microscopy, intracellular analysis, and single-cell analysis in a biological system (i.e., neocortex and retina), are reviewed. The unique features and remaining challenges of these techniques are discussed.

Lizhen Chen, Ying Fu, Naixiang Wang et al.

ACS Applied Materials &amp; Interfaces • 2018

Cell surface glycans play critical roles in diverse biological processes, such as cell-cell communication, immunity, infection, development, and differentiation. Their expressions are closely related to cancer growth and metastasis. This work demonstrates an organic electrochemical transistor (OECT)-based biosensor for the detection of glycan expression on living cancer cells. Herein, mannose on human breast cancer cells (MCF-7) as the target glycan model, poly dimethyl diallyl ammonium chloride-multiwall carbon nanotubes (PDDA-MWCNTs) as the loading interface, concanavalin A (Con A) with active mannose binding sites, aptamer and horseradish peroxidase co-immobilized gold nanoparticles (HRP-aptamer-Au NPs) as specific nanoprobes are used to fabricate the OECT biosensor. In this strategy, PDDA-MWCNT interfaces can enhance the loading of Con A, and the target cells can be captured through Con A via active mannose binding sites. Thus, the expression of cell surface can be reflected by the amount of cells captured on the gate. Specific nanoprobes are introduced to the captured cells to produce an OECT signal because of the reduction of hydrogen peroxide catalyzed by HRP conjugated on Au nanoparticles, while the aptamer on nanoprobes can selectively recognize the MCF-7 cells. It is reasonable that more target cells are captured on the gate electrode, more HRP-nanoprobes are loaded thus a larger signal response. The device shows an obvious response to MCF-7 cells down to 10 cells/μL and can be used to selectively monitor the change of mannose expression on cell surfaces upon a treatment with the N-glycan inhibitor. The OECT-based biosensor is promising for the analysis of glycan expressions on the surfaces of different types of cells.

Yi-Fan Ruan, Hai‐Yan Wang, Xiao-Mei Shi et al.

Analytical Chemistry • 2020

Engineered nanopipette tools have recently emerged as a powerful approach for electrochemical nanosensing, which has major implications in both fundamental biological research and biomedical applications. Herein, we describe a generic method of target-triggered assembly of aptamers in a nanopipette for nanosensing, which is exemplified by sensitive and rapid electrochemical single-cell analysis of adenosine triphosphate (ATP), a ubiquitous energy source in life and important signaling molecules in many physiological processes. Specifically, a layer of thiolated aptamers is immobilized onto a Au-coated interior wall of a nanopipette tip. With backfilled pairing aptamers, the engineered nanopipette is then used for probing intracellular ATP via the ATP-dependent linkage of the split aptamers. Due to the higher surface charge density from the aptamer assembly, the nanosensor would exhibit an enhanced rectification signal. Besides, this ATP-responsive nanopipette tool possesses excellent selectivity and stability as well as high recyclability. This work provides a practical single-cell nanosensor capable of intracellular ATP analysis. More generally, integrated with other split recognition elements, the proposed mechanism could serve as a viable basis for addressing many other important biological species.

Liming Bai, Cristina García Elósegui, Weiqi Li et al.

Frontiers in Chemistry • 2019

Organic electrochemical transistors (OECTs) are recently developed high-efficient transducers not only for electrochemical biosensor but also for cell electrophysiological recording due to the separation of gate electrode from the transistor device. The efficient integration of OECTs with electrochemical gate electrode makes the as-prepared sensors with improved performance, such as sensitivity, limit of detection, and selectivity. We herein reviewed the recent progress of OECTs-based biosensors and cell electrophysiology recording, mainly focusing on the principle and chemical design of gate electrode and the channel. First, the configuration, work principle, semiconductor of OECT are briefly introduced. Then different kinds of sensing modes are reviewed, especially for the biosensing and electrophysiological recording. Finally, the challenges and opportunities of this research field are discussed.

Xiao Su, T. A. Hatton

Physical Chemistry Chemical Physics • 2017

Adsorption at charged interfaces plays an important role across all aspects of physical chemistry, from biological interactions within living organisms to chemical processes such as catalysis and separations. With recent advances in materials chemistry, there are a host of modified electrodes being investigated for electrosorption, especially in separations science. In this perspective, we provide an overview of functional interfaces being used for electrosorption, ranging from electrochemical separations such as deionization and selective product recovery to biological applications. We cover the various molecular mechanisms which can be used to enhance ion capacity, and in some cases, provide selectivity; as well as discuss the parasitic Faradaic reactions which often impair electrosorption performance. Finally, we point to the importance of electrochemical configurations, in particular the advantages of asymmetric cell design, and highlight the opportunities for selective electrosorption brought about by redox-mediated systems.

N. Askari, Dr. Mohammadreza Askari, A. Di Bartolomeo

Journal of The Electrochemical Society • 2022

A multi-component nanocomposite consisting of manganese oxide (Mn3O4), cobalt oxide (Co3O4), and reduced graphene oxide (rGO) in the form of Mn3O4-Co3O4-rGO was synthesized by the hydrothermal method. Cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry analyses were performed to investigate the synergistic effect of metal oxides on the surface of rGO nano-sheets in the methanol oxidation reaction and ethanol oxidation reaction process. The good electrochemical results show that Mn3O4-Co3O4-rGO can be a promising, inexpensive nano-catalyst for application in alcohol fuel cells. In addition, as nanoparticles inhibit cancer cells growth by producing reactive oxygen species (ROS), we explored the synergic effect of the three-component synthetic nanomaterial in gastric cancer cells (AGS). Results indicated that Mn3O4-Co3O4-rGO inhibited AGS cell growth by induction of ROS, upregulation of Mir-20a-5p, and downregulation of ZBTB4 gene. This might provide a novel molecular-targeted strategy of microRNA-based therapeutics for gastric cancer treatment.