Co-reactant-on-Demand ECL: Electrogenerated Chemiluminescence by the in Situ Production of S2O82– at Boron-Doped Diamond Electrodes

Versatile and Ultrasensitive Electrochemiluminescence Biosensor for Biomarker Detection Based on Nonenzymatic Amplification and Aptamer-Triggered Emitter Release

Electrochemiluminescence (ECL), as a sensitive and controllable assay, offers a considerable opportunity for multiple types of biomarkers detection. However, constructing such a biosensor remains a significant challenge. Herein, an ultrasensitive and versatile ECL biosensor was constructed to detect multiple types of biomarkers from breast cancer by taking the strategies of nonenzymatic catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) amplification, as well as aptamer-triggered emitter release. Concretely, with the appearance of target 1 microRNA-21 (miRNA-21), abundant double-stranded DNA (dsDNA) polymers were generated on this biosensing surface via amplification circuits of CHA and HCR, which could be intercalated into substantial ([Ru(bpy)₂dppz]Cl₂) as ECL indicators to obtain an obvious enhancement of ECL signal for target 1 detection with a detection limit (0.1 fM). Furthermore, in the presence of target 2 human mucin 1 (MUC1) protein, the ECL signal had a distinct decrease, because aptamer recognition induced the release of [Ru(bpy)₂dppz]Cl₂ from the sensing surface, thus, achieving a sensitive detection for MUC1 with a detection limit (2.4 fg·mL^-1). Simultaneously, this sensing platform was applied to monitor the biomarkers from MDA-MB-231 breast cancer cells, suggesting that this method was applicable to detect real samples. Therefore, this platform is an applicable and versatile implement for the determination of multiple types of biomarkers to improve diagnostic accuracy and efficiency.

Conductive diamond: synthesis, properties, and electrochemical applications

This review summarizes systematically the growth, properties, and electrochemical applications of conductive diamond.

A widened emission window of the peroxydisulfate-oxygen system for the detection of L-alanine

Peroxydisulfate-oxygen (S₂O₈^2--O₂) system has become one of the most used systems in electrogenerated chemiluminscence (ECL) field. Due to S₂O₈^2- can be used as Fenton Reagent, this work designed an ECL biosensor based on the S₂O₈^2--O₂ system for the detection of L-alanine in a widened emission window and using hemin/G-quadruplex and platinum and palladium nanowires (Pt-Pd NWs) to in situ generate O₂ to amplify the ECL intensity. The proposed ECL sensor showed an excellent analytical property for the detection of L-alanine in a linear range of 5.0 × 10^-3 M to 1.0 × 10^-8 M with the detection limit of 3.3 × 10^-9 M (S/N = 3). This work with high selectivity, stability and reproducibility may open a new door to apply S₂O₈^2- in ECL field.

Coupled Fluorometer-Potentiostat System and Metal-Free Monochromatic Luminophores for High-Resolution Wavelength-Resolved Electrochemiluminescent Multiplex Bioassay

The sensitive simultaneous detection of multiple biomarkers is critical for the early diagnosis of diseases. Electrochemiluminescence (ECL) offers outstanding advantages, e.g., low background, over other optical sensing techniques. However, multiplexed ECL bioassay is hindered not only by the lack of generally available ECL spectrometers but also by the limited number of biocompatible monochromatic ECL luminophores for decades. Herein, we report addressing these issues by re-examination of the recent tabletop spectrofluorometer coupled potentiostat as a high-resolution ECL spectrum acquisition system and using carbon nitrides as monochromatic luminophores. A wavelength-resolved multiplexing ECL biosensor is demonstrated to simultaneously detect CA19-9 and mesothelin, two pancreatic cancer biomarkers, at a single-electrode interface. This work could initiate new opportunities for more general multiplex ECL biosensors with competitive performances.

Boron Doped Diamond: A Designer Electrode Material for the Twenty-First Century

Boron doped diamond (BDD) is continuing to find numerous electrochemical applications across a diverse range of fields due to its unique properties, such as having a wide solvent window, low capacitance, and reduced resistance to fouling and mechanical robustness. In this review, we showcase the latest developments in the BDD electrochemical field. These are driven by a greater understanding of the relationship between material (surface) properties, required electrochemical performance, and improvements in synthetic growth/fabrication procedures, including material postprocessing. This has resulted in the production of BDD structures with the required function and geometry for the application of interest, making BDD a truly designer material. Current research areas range from in vivo bioelectrochemistry and neuronal/retinal stimulation to improved electroanalysis, advanced oxidation processes, supercapacitors, and the development of hybrid electrochemical-spectroscopic- and temperature-based technology aimed at enhancing electrochemical performance and understanding.

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

A single-electrode electrochemical system uses only one electrode for multiplex experiments, and is a highly cheap platform for high throughput analysis.

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. This enables multiplex electrochemiluminescence analysis with high sensitivity at a very low safe voltage using a smartphone as a detector. For the multiplex analysis, the SEES using a single electrode is much simpler, cheaper and more user-friendly than conventional electrochemical systems and bipolar electrochemical systems using electrode arrays. Moreover, SEESs are free from the electrochemiluminescent background problem from driving electrodes in bipolar electrochemical systems. Since numerous electrodes and cover materials can be used to fabricate SEESs readily and electrochemistry is being extensively used, SEESs are very promising for broad applications, such as drug screening and high throughput analysis.

Boron-doped diamond electrode: Preparation, characterization and application for electrocatalytic degradation of m-dinitrobenzene

Boron-doped diamond (BDD) electrode was successfully prepared via microwave plasma chemical vapor deposition method and it was used in electrocatalytic degradation of m-dinitrobenzene (m-DNB). The electrocatalytic degradation efficiency of m-DNB was evaluated under different experimental parameters including current density, temperature, pH, Na₂SO₄ concentration and initial m-DNB concentration. Under optimal parameters, degradation efficiency of m-DNB reached up to 82.7% after 150min. The degradation process of m-DNB was fitted well with pseudo first-order kinetics. Moreover, UV and HPLC analyses implied that m-DNB was totally destroyed and mineralized after 240min degradation, and the proposed mechanism during the electrocatalytic degradation process was analyzed. All these results demonstrated that BDD electrode possessed excellent electrocatalytic property and showed a great potential application in wastewater treatment.

Highly sensitive novel cathodic electrochemiluminescence of tris(2,2′-bipyridine)ruthenium(ii) using glutathione as a co-reactant

Herein, glutathione was used as a co-reactant for the first time to generate a novel, highly stable, and enhanced cathodic ECL on GCE surface using the Ru(bpy)₃²⁺ molecule in an alkaline PBS.