Heavy trace elements (HTEs), including toxic metals such as Pb, Hg, Cd, and As, present a growing environmental and public health concern due to their persistence and bioaccumulation in water and soil systems. Driven by increased demand for strategic and rare earth metals in emerging technologies, anthropogenic activities such as mining, industrial discharge, and agriculture have intensified environmental contamination. Traditional detection methods such as atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS), and X-ray fluorescence (XRFS), although highly sensitive, are limited by their cost, complexity, and lack of suitability for continuous measurement (real-time) without taking samples to the laboratory for analysis ( and online) applications. This review highlights recent advances in standard electrochemical techniques, particularly voltammetric ones such as square wave voltammetry (SWV), differential pulse voltammetry (DPV), and anodic stripping voltammetry (ASV), in addition to non-voltammetric including electrochemical impedance spectroscopy (EIS) and chronopotentiometry methods enhanced by nanomaterials, including carbon nanomaterials: single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs); metal and metal oxide nanoparticles; polymer and hybrid nanocomposites; and metal organic frameworks. These materials improve sensor sensitivity, selectivity, stability, and portability of standard electrochemical methods, making them ideal for real-time and and online for HTEs. In this review article, current innovations in standard electrochemical techniques with nanomaterials and hybrid nanocomposites improving sensor architecture, functionalization, sensitivity and selectivity are discussed alongside performance metrics and limitations.

The use of carbon-based electrodes for direct neurochemical detection along the brain-immune axis is emerging as a promising frontier. Carbon is commonly chosen as an electrode material due to its numerous advantages, including cost-effectiveness, high electrical conductivity, excellent chemical stability, wide electrochemical window, and biocompatibility. To further enhance performance, carbon fibers have been coated with nanomaterials including carbon nanotubes (CNTs), graphene, carbon nanospikes, among others. Traditional carbon electrodes-typically constructed from carbon fibers-are limited by their heterogeneity, which restricts their adaptability. Recent advancements have moved toward developing highly sensitive and selective carbon materials through customization. The current research is increasingly focused on developing alternative materials to replace carbon fibers, with the aim of preventing coating degradation, improving sensitivity, achieving frequency-independent properties, and lowering detection limits. This current opinion discusses the key innovations in modern carbon-based materials for brain-immune studies, with an emphasis on the importance of tailoring surfaces for specific analytes and applications.

Electrochemical correlative microscopy involves the pairing of electrochemical measurements with one or multiple orthogonal microscopic techniques. By integrating electrochemical measurements, especially scanning electrochemical probe microscopies (SEPMs), with correlative optical microscopy, spectroscopy, or electron microscopies, rich information complimentary to the electrochemical measurement can be obtained. This information can reveal detailed structure-property-activity relationships at electrochemical interfaces. Additionally, they can showcase visualizations of electrochemical phase transitions or mechanisms and assist in high-throughput synthesis and screening of materials for various electrochemical applications. In this perspective, we will use a few examples highlighting advances in electrochemical correlative microscopy over the past two years, focusing on the theme involving electrochemical energy storage and conversion. We anticipate new fundamental understanding of electrochemical interfaces will be elucidated through multitechnique platforms, and the outlook of future development of electrochemical correlative microscopy will be discussed.

Interfacial science and electroorganic syntheses are inextricably linked because all electrochemical reactions occur at the interface between the electrode and the solution. Thus, the surface chemistry of the electrode material impacts the organic reaction selectivity. In this short review, we highlight emergent examples of electrode surface chemistries that enable selective electroorganic synthesis in three reaction classes: (1) hydrogenation, (2) oxidation, and (3) reductive C‒C bond formation between two electrophiles. We showcase the breadth of techniques, including materials and characterization, requisite to establish mechanistic schemes consistent with the observed reactivity patterns. Leveraging an electrode's unique surface chemistry will provide complementary approaches to tune the selectivity of electroorganic syntheses and unlock an electrode's catalytic properties.

This review summarizes the recent advancements in alternating current (AC)-driven electroorganic synthesis since 2021 and discusses the reactivities AC electrolysis provides to achieve new and unique organic transformations.

Rapid, accurate diagnoses are central to future efficient healthcare to identify diseases at early stages, avoid unnecessary treatment, and improve outcomes. Electrochemical techniques have been applied in many ways to support clinical applications by enabling the analysis of relevant disease biomarkers in user-friendly, sensitive, low-cost assays. Electrochemistry offers a launchpad for multiplexed biomarker assays that offer more accurate and precise diagnostics compared to single biomarker assays. In this short review, we underpin the importance of multiplexed analyses and provide a universal overview of current electrochemical assay strategies for multiple biomarkers. We highlight relevant examples of electrochemical methods that successfully quantify important disease biomarkers. Finally, we offer a future outlook on possible strategies that can be employed to increase throughput, sensitivity, and specificity of multiplexed electrochemical assays.

Nucleic acid-based electrochemical (NBE) sensors offer real-time and reagent-free sensing capabilities that overcome limitations of target-specific reactivity via affinity-based molecular detection. By leveraging affinity probes, NBE sensors become modular and versatile, allowing the monitoring of a variety of molecular targets by simply swapping the recognition probe without the need to change their sensor architecture. However, NBE sensors have not been rigorously validated in terms of analytical performance and clinical agreement relative to benchmark methods. In this article, we highlight reports from the past three years that evaluate NBE sensors performance . We hope this discussion will inspire future translational efforts with statistically robust experimental design, thus enabling real-world clinical applications and commercial development of NBE sensors.

Sepsis is a life-threatening dysfunction of organ systems caused by a dysregulated immune system because of an infectious process. It remains one of the leading causes of hospital mortality and of hospital readmissions in the United States. Mortality from sepsis increases with each hour of delayed treatment, therefore, diagnostic devices that can reduce the time from the onset of a patient's infection to the delivery of appropriate therapy are urgently needed. Likewise, tools that are capable of high-frequency testing of clinically relevant biomarkers are required to study disease progression. Electrochemical biosensors offer important advantages such as high sensitivity, fast response, miniaturization, and low cost that can be adapted to clinical needs. In this review paper, we discuss the current state, limitations, and future directions of electrochemical-based point-of-care detection platforms that contribute to the diagnosis and monitoring of sepsis.

Molecular dynamics simulations and vibrational sum-frequency spectroscopy are historically the main techniques applied to the description of the molecular structure and dynamics of the immiscible liquid/liquid interface. A molecular sharpness is estimated for oil/water interfaces, with an interfacial width that extends from hundreds of Å to 1 nm. However, electrochemical studies have elucidated a deeper liquid/liquid interface on the order of several micrometers. The breaking down of single-entity electrochemistry to simpler systems and the combination of high-resolution microscopies is confirming a larger extension of the interface. What can be the role of the electrochemist in clarifying this fundamental question? We try to give a suggestion at the end of a brief historical overview of the liquid/liquid interface studies.

Traditional carbon electrodes are made of glassy carbon or carbon fibers and have limited shapes. 3D printing offers many advantages for manufacturing carbon electrodes, such as complete customization of the shape and the ability to fabricate devices and electrodes simultaneously. Additive manufacturing is the most common 3D printing method, where carbon materials are added to the material to make it conductive, and treatments applied to enhance electrochemical activity. A newer form of 3D printing is 2-photon lithography, where electrodes are printed in photoresist via laser lithography and then annealed to carbon by pyrolysis. Applications of 3D printed carbon electrodes include nanoelectrode measurements of neurotransmitters, arrays of biosensors, and integrated electrodes in microfluidic devices.

Rapid, reliable, and cost-effective pathogen detection sensors are reshaping modern biomedical devices to a competent form for health care applications. Current approaches rely on microscopy, spectroscopy, polymerase chain reaction (PCR), and electrochemistry. The latter is an intriguing way of using electricity to drive a (bio)chemical reaction, the electronic read-out of which informs on the state of infection. Specifically, a recent electrochemical platform for pathogenic detection utilizes imprinted electrodes to detect species with high specificity based on their spatial 3D "fingerprint." In this mini-review, we describe different compositions and techniques for fabricating imprinted electrodes that target various species of bacteria and viruses. We elaborate on the possible electrochemical pathogen detection methods, compare their performance with non-electrochemical methods, and emphasize the benefit of coupling electrochemistry with other established techniques. As a showcase, we contrast the ability of electrochemical DNA biosensors and imprinted electrodes to detect Zika and SARS-CoV-2 virus.

Nucleic acid-based electrochemical sensors are a versatile technology enabling affinity-based detection of a great variety of molecular targets, regardless of inherent electrochemical activity or enzymatic reactivity. Additionally, their modular interface and ease of fabrication enable rapid prototyping and sensor development. However, the technology has inhibiting limitations in terms of long-term stability that have precluded translation into clinically valuable platforms like continuous molecular monitors. In this opinion, we discuss published methods to address various aspects of sensor stability, including thiol-based monolayers and anti-biofouling capabilities. We hope the highlighted works will motivate the field to develop innovative strategies for extending the long-term operational life of nucleic acid-based electrochemical sensors.

It is easy to carry out electrochemical analysis. It is demanding, however, to do it right, as inherent challenges, emerging from details in the data collection and the result interpretation, frequently present themselves. In pertinence to electron-donor-acceptor interactions, herein, we focus on voltammetrically obtained electrochemical potentials and their immense utility for extracting important characteristics of molecular analytes. Recommendations how to address key pending challenges, based on recent developments in electroanalysis and charge-transfer science, accompany the discussions on undesired impacts from irreversibility of oxidation and reduction, supporting electrolytes, choices of reference, liquid junctions, and 'nonideality' of molecular shapes. As the wide implications of charge transfer are indisputable, using the tools at our disposal for improving the reliability of electroanalysis is crucial for advancing modern science and engineering.

Rapid detection of human coronavirus disease 2019, termed as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 infection, is urgently needed for containment strategy owing to its unprecedented spreading. Novel biosensors can be deployed in remote clinical settings without central facilities for infection screening. Electrochemical biosensors serve as analytical tools for rapid detection of viral structure proteins, mainly spike (S) and nucleocapsid (N) proteins, human immune responses, reactive oxygen species, viral ribonucleic acid, polymerase chain reaction by-products, and other potential biomarkers. The development of point-of-care testing devices is challenging due to the requirement of extensive validation, a time-consuming and expensive step. Together with specific biorecognition molecules, nanomaterial-based biosensors have emerged for the fast detection of early viral infections.

Current fuel-cell catalysts for oxygen reduction reaction (ORR) and H oxidation use precious metals and, for ORR, require high overpotentials. In contrast, metalloenzymes perform their respective reaction at low overpotentials using earth-abundant metals, making metalloenzymes ideal candidates for inspiring electrocatalytic design. Critical to the success of these enzymes are redox-active metal centers surrounding the enzyme active sites that ensure fast electron transfer (ET) to or away from the active site, by tuning the catalytic potential of the reaction as observed in multicopper oxidases but also in dictating the catalytic bias of the reaction as realized in hydrogenases. This review summarizes recent advances in studying these ET centers in multicopper oxidases and heme-copper oxidases that perform ORR and hydrogenases in carrying out H oxidation. Insights gained from understanding how the reduction potential of the ET centers effects reactivity at the active site in both the enzymes and their models are provided.

Even though global health has been steadily improved, the global disease burden associated with communicable and non-communicable diseases extensively increased healthcare expenditure. The present COVID-19 pandemic scenario has again ascertained the importance of clinical diagnostics as a basis to make life-saving decisions. In this context, there is a need for developing next-generation integrated smart real-time responsive biosensors with high selectivity and sensitivity. The emergence of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas biosensing systems has shown remarkable potential for developing next-generation biosensors. CRISPR/Cas integrated electrochemical biosensors (E-CRISPR) stands out with excellent properties. In this opinionated review, we illustrate the rapidly evolving applications for E-CRISPR-integrated detection systems towards biosensing and the future scope associated with E-CRISPR based diagnostics.

Potentiometric biosensors are incredibly versatile tools with budding uses in industry, security, environmental safety, and human health. This mini-review on recent (2018-2020) advances in the field of potentiometric biosensors is intended to give a general overview of the main types of potentiometric biosensors for novices while still providing a brief but thorough summary of the novel advances and trends for experienced practitioners. These trends include the incorporation of nanomaterials, graphene, and novel immobilization materials, as well as a strong push towards miniaturized, flexible, and self-powered devices for in-field or at-home use.

Most electrochemical processes are stochastic and discrete in nature. Yet experimental observables, e.g., vs , are typically smooth and deterministic, due to many events/processes, e.g., electron transfers, being averaged together. However, when the number of entities measured approaches a few or even one, stochasticity frequently emerges. Yet all is not lost! Probabilistic and statistical interpretation can generate insights matching or superseding those from macroscale/ensemble measurements, revealing phenomena that were hitherto averaged over. Herein, we review recent literature examples of stochastic processes in single-entity electrochemistry, highlighting strategies for interpreting stochasticity, contrasting them with macroscale measurements, and describing the insights generated.

Herein, we have summarized and argued about biomarkers and indicators used for the detection of severe acute respiratory syndrome coronavirus 2. Antibody detection methods are not considered suitable to screen individuals at early stages and asymptomatic cases. The diagnosis of coronavirus disease 2019 using biomarkers and indicators at point-of-care level is much crucial. Therefore, it is urgently needed to develop rapid and sensitive detection methods which can target antigens. We have critically elaborated key role of biosensors to cope the outbreak situation. In this review, the importance of biosensors including electrochemical, surface enhanced Raman scattering, field-effect transistor, and surface plasmon resonance biosensors in the detection of severe acute respiratory syndrome coronavirus 2 has been underscored. Finally, we have outlined pros and cons of diagnostic approaches and future directions.

This short review focuses on the recent developments of the Microbial Fuel Cell (MFC) technology, its scale-up and implementation in real world applications. Microbial Fuel Cells produce (bio)energy from waste streams, which can reduce environmental pollution, but also decrease the cost of the treatment. Although the technology is still considered "new", it has a long history since its discovery, but it is only now that recent developments have allowed its implementation in real world settings, as a precursor to commercialisation.