Selective Electrochemical Biosensors for Tyrosinase and Tyramine via Enzyme-Mediated Oxidation Reaction.

Tyrosinase, a copper-containing oxidase, holds promise as a critical biomarker for diverse skin-related infections and vitiligo and melanoma tumors. Beyond its role as a critical biomarker and in biological pigmentation, tyrosinase is also involved in the oxidation of biogenic amines such as tyramine. Tyramine as a tyrosinase substrate serves as a precursor in the synthesis of various neurotransmitters such as dopamine and norepinephrine and contributes to significant neurological processes.

Electrochemical Detection of Hydrogen Peroxide at High Concentrations Using Hastelloy G35 Electrode.

The detection of hydrogen peroxide (HO) at elevated concentrations while eliminating oxygen interference presents a significant challenge. Nickel-based stainless steel, such as Hastelloy G35, has shown excellent corrosion resistance. However, it has never been used in electroanalysis.

Signal-On Detection of Dopamine and Tyrosinase Using Tris(hydroxypropyl)phosphine as a New Lucigenin Chemiluminescence Coreactant.

Dopamine (DA) is a very imperative neurotransmitter in our body, since it contributes to several physiological processes in our body, for example, memory, feeling, cognition, cardiovascular diseases, and hormone secretion. Meanwhile, tyrosinase is a critical biomarker for several dangerous skin diseases, including vitiligo and melanoma cancer. Most of the reported chemiluminescent (CL) methods for monitoring DA and tyrosinase are signal-off biosensors.

VS Nanodendrites with Narrow Bandgaps in Activating Dissolved Oxygen for Boosted Chemiluminescence and Hemin Detection by Unexpected Quenching.

Chemiluminescence (CL)-based analytical methods utilize luminophores that need to be activated with an oxidizing agent to trigger CL emission. Despite its susceptibility to decomposition when exposed to external light or trace metals, hydrogen peroxide (HO) has been widely used to develop chemiluminescent methods due to the limited number of suitable alternatives for activating chemiluminescent luminophores. Also, analytical methods based on the well-known luminol/HO CL system have low sensitivity.

Ultrafast Response and High Selectivity of Diethylamine Gas Sensors at Room Temperature Using MOF-Derived 1D CuO Nano-Ellipsoids.

Environmental and health monitoring requires low-cost, high-performance diethylamine (DEA) sensors. Materials based on metal-organic frameworks (MOFs) can detect hazardous gases due to their large specific surface area, many metal sites, unsaturated sites, functional connectivity, and easy calcination to remove the scaffold. However, developing facile materials with high sensitivity and selectivity in harsh environments for accurate DEA detection at a low detection limit (LOD) at room temperature (RT) is challenging.

Advances in miniaturized nanosensing platforms for analysis of pathogenic bacteria and viruses.

Pathogenic bacteria and viruses are the main causes of infectious diseases all over the world. Early diagnosis of such infectious diseases is a critical step in management of their spread and treatment of the infection in its early stages. Therefore, the innovation of smart sensing platforms for point-of-care diagnosis of life-threatening infectious diseases such as COVID-19 is a prerequisite to isolate the patients and provide them with suitable treatment strategies.

Much Stronger Chemiluminescence of 9-Mesityl-10-methylacridinium Ion than Lucigenin at Neutral Conditions for Co Detection.

9-Mesityl-10-methylacridinium ion (Acr-Mes) is a donor-acceptor molecule with a much longer lifetime and a higher energy electron transfer excited state than natural photosynthetic reaction centers. Unlike lucigenin with a coplanar geometry, Acr-Mes has an orthogonal geometry. There is no π conjugation between Acr and Mes.

Electrochemical Detection of Dopamine using a Phenyl Carboxylic Acid-Functionalized Electrode Made by Electrochemical Reduction of a Diazonium Salt.

A glassy carbon electrode (GCE) has been modified by an in situ electrochemical reduction of an aryldiazonium salt generated from the reaction of 4-aminobenzoic acid and sodium nitrite in acidic ethanolic solution. The as-prepared phenyl carboxylic acid-modified glassy carbon electrode has been, for the first time, used for the electrochemical determination of dopamine. Under optimal experimental parameters, outstanding electrocatalytic activity, high sensitivity at a LOD of 5.

Dithiothreitol-Lucigenin Chemiluminescent System for Ultrasensitive Dithiothreitol and Superoxide Dismutase Detection.

1,4-Dithiothreitol (DTT), a highly water-soluble and well-known reducing agent for preservation and regeneration of sulfhydryl groups in biomedical applications, has been developed as an efficient and stable coreactant of lucigenin for the first time. DTT efficiently reacts with lucigenin to generate intense chemiluminescence (CL), eliminating the need for external catalysts to facilitate the lucigenin CL. The DTT-lucigenin CL is approximately 15-fold more intense when compared with the lucigenin-HO classical system.

Chemiluminescence of lucigenin-tetracycline and its application for sensitive determination of procyanidin.

Tetracycline was reported to trigger intense lucigenin chemiluminescence (CL). Based on its significant quenching to lucigenin-tetracycline CL, procyanidin was detected. The mechanism of the lucigenin-tetracycline CL and its quenching by procyanidin were proposed.

Lucigenin-pyrogallol chemiluminescence for the multiple detection of pyrogallol, cobalt ion, and tyrosinase.

Developing new, cheap, sensitive and selective chemiluminescence (CL) systems with multiple detection properties is still a big challenge for biological and environmental applications. Here, we report a new CL system having multiple detection applications (environmental and biological). The developed lucigenin-pyrogallol system gave an enhancement (190 times) over the conventional lucigenin-HO CL system.

Recent advances in microchip electrophoresis for analysis of pathogenic bacteria and viruses.

Life-threatening diseases, such as hepatitis B, pneumonia, tuberculosis, and COVID-19, are widespread due to pathogenic bacteria and viruses. Therefore, the development of highly sensitive, rapid, portable, cost-effective, and selective methods for the analysis of such microorganisms is a great challenge. Microchip electrophoresis (ME) has been widely used in recent years for the analysis of bacterial and viral pathogens in biological and environmental samples owing to its portability, simplicity, cost-effectiveness, and rapid analysis.

Potentiometric sensors for the determination of pharmaceutical drugs.

Potentiometric sensors based on ion-selective membrane electrodes have continued to get great attention from the scientific community. These sensors have been employed in several applications including medicine, forensic analysis, environmental assessment, industry, agriculture, and pharmaceutical drug analysis. Indeed, these sensors possess several advantages, for example, simple design, fabrication, and manipulation, rapid response time, good selectivity, applicability to colored and turbid solutions, and possible interfacing with automated and computerized systems.

Dimeric G-Quadruplex: An Efficient Probe for Ultrasensitive Fluorescence Detection of Mustard Compounds.

Some mustard compounds (mustards) are highly toxic chemical warfare agents. Some are explored as new anticancer drugs. Therefore, the fast, selective, and sensitive detection of mustards is extremely important for public security and cancer therapy.

Detection of ascorbic acid based on its quenching effect on luminol-artemisinin chemiluminescence.

We find that luminol can react with artemisinin (ART) to produce chemiluminescence (CL) in the absence of a catalyst and ascorbic acid (AA) can quench luminol-ART CL. Based on its efficient inhibition effect on luminol-ART CL, a new AA detection method is established. The calibration curve for the determination of AA is in the linear range of 5 × 10 M to 1 × 10 M with a detection limit of 50 nM, which is more sensitive than many other reported methods.

Development of luminol-fluorescamine-PVP chemiluminescence system and its application to sensitive tyrosinase determination.

Fluorescamine is a popular fluorescent probe. We report for the first time that luminol chemiluminescence (CL) can be enhanced by fluorescamine in the presence of PVP. The CL intensity of luminol-fluorescamine-PVP is about 26 times stronger than that of luminol.

Chemiluminescent determination of L-cysteine with the lucigenin-carbon dot system.

This work describes a new chemiluminescence (CL) system that is composed of lucigenin and carbon dots (CDs). The CDs display absorption peak at 260 nm and fluorescence with a emission peak centered at 524 nm (photo-excited at 470 nm). They were synthesized by hydrothermal treatment of starch and characterized by Fourier transform infrared spectroscopy, high resolution transmission electron microscopy, UV-vis absorption spectra and fluorescence spectra.

Electrochemiluminescence of 3,4,9,10-perylenetetracarboxylic acid/oxamic hydrazide and its application in the detection of tannic acid.

Perylene and its derivatives are often used in many analytical fields, but its electrochemiluminescence (ECL) behavior has been rarely reported. Here, a novel anodic ECL of 3,4,9,10-perylenetetracarboxylic acid (PTCA)/oxamic hydrazide (OHZ) has been investigated for the first time with OHZ as the coreactant. The mechanism of the PTCA/OHZ ECL system is discussed.

Recent advances in nanomaterial-based capillary electrophoresis.

This review gives a summary of applications of different nanomateials, such as gold nanoparticles (AuNPs), carbon-based nanoparticles, magnetic nanoparticles (MNPs), and nano-sized metal organic frameworks (MOFs), in electrophoretic separations. This review also emphasizes the recent works in which nanoparticles (NPs) are used as pseudostationary phase (PSP) or immobilized on the capillary surface for enhancement of separation in CE, CEC, and microchips electrophoresis.

Chemiluminescence of Lucigenin/Riboflavin and Its Application for Selective and Sensitive Dopamine Detection.

Lucigenin-riboflavin chemiluminescence is reported for the first time. Moreover, most dopamine chemiluminescence (CL) detection methods are based on the quenching of CL by dopamine. In contrast, we find that dopamine can significantly enhance lucigenin/riboflavin CL and establish a highly sensitive turn-on method for dopamine detection based on the enhancement of lucigenin/riboflavin CL.

A single-electrode electrochemical system for multiplex electrochemiluminescence analysis based on a resistance induced potential difference.

Developing low-cost and simple electrochemical systems is becoming increasingly important but still challenged for multiplex experiments. Here we report a single-electrode electrochemical system (SEES) using only one electrode not only for a single experiment but also for multiplex experiments based on a resistance induced potential difference. SEESs for a single experiment and multiplex experiments are fabricated by attaching a self-adhesive label with a hole and multiple holes onto an ITO electrode, respectively.

Hierarchical concave layered triangular PtCu alloy nanostructures: rational integration of dendritic nanostructures for efficient formic acid electrooxidation.

The rational construction of multi-dimensional layered noble metal nanostructures is a great challenge since noble metals are not layer-structured materials. Herein, we report a one-pot hydrothermal synthetic method for PtCu hierarchical concave layered triangular (HCLT) nanostructures using dl-carnitine, KI, poly(vinylpyrrolidone), CuCl2, and H2PtCl6. The PtCu HCLT nanostructure is comprised of multilayered triangular dendrites.

Chemiluminescence of Lucigenin-Allantoin and Its Application for the Detection of Allantoin.

Allantoin has been reported as a promising biomarker for monitoring of oxidative stress in humans and widely utilized in a variety of topical pharmaceuticals and cosmetics. Currently, the detection of allantoin is achieved by using chromatographic coupled techniques, which needs sample pre-extraction, derivatization, complex matrixes, and expensive instrumentation. Herein we report both the intense chemiluminescence of allantoin with lucigenin and the chemiluminescent detection of allantoin for the first time.

A miniature origami biofuel cell based on a consumed cathode.

Considerable interest has been focused on miniature biofuel cells (BFCs) because of their portability and possibility to be implantable. Origami devices with hollow channels will provide novel insight into the assembly methods of miniature BFCs. Herein a miniature origami BFC has been fabricated from a MnO-graphite flake consumed solid-state cathode.

G-quadruplex enhanced fluorescence of DNA-silver nanoclusters and their application in bioimaging.

Guanine proximity based fluorescence enhanced DNA-templated silver nanoclusters (AgNCs) have been reported and applied for bioanalysis. Herein, we studied the G-quadruplex enhanced fluorescence of DNA-AgNCs and gained several significant conclusions, which will be helpful for the design of future probes. Our results demonstrate that a G-quadruplex can also effectively stimulate the fluorescence potential of AgNCs.