Light in Electrochemistry

Abstract

Electrochemistry represents an important analytical technique used to acquire and assess chemical information in detail, which can aid fundamental investigations in various fields, such as biological studies. For example, electrochemistry can be used as simple and cost-effective means for bio-marker tracing in applications, such as health monitoring and food security screening. In combination with light, powerful spatially-resolved applications in both the investigation and manipulation of biochemical reactions begin to unfold. In this article, we focus primarily on light-addressable electrochemistry based on semiconductor materials and light-readable electrochemistry enabled by electrochemiluminescence (ECL). In addition, the emergence of multiplexed and imaging applications will also be introduced.

Light-Addressable Electrochemical Sensors toward Spatially Resolved Biosensing and Imaging Applications

“…Arising from the photoelectric effect in semiconductors, light illumination in the LAES can locally increase the conductivity of the photoactive layer and create a virtual electrode to record local electrochemical processes. ,− We termed this “light addressability”, which makes it possible to use a light beam to define the shape, size, and location of the measured area on an unstructured sensor surface without any complex bonding, wiring, or encapsulation. , As one of the most significant and attractive characteristics, light addressability enables the application of an LAES in two different ways. , On the one hand, the LAES can serve as a multichannel or multiplexed electrochemical sensor to detect various analytes on the surface of a single macroscopic substrate. This can be accomplished by separating the substrate into a plurality of areas, preparing the individual areas with different photoactive or biosensitive materials, and then illuminating each area with a light source. , On the other hand, by addressing a 2D array of measurement sites with each site corresponding to a pixel in a chemical image, the LAES can visualize the 2D distribution of target chemical or biological substances in the solution or in contact with the sensing surface. , We will give a detailed review on the two specific applications in the following sections.…”

“…17,31 As one of the most significant and attractive characteristics, light addressability enables the application of an LAES in two different ways. 55,56 On the one hand, the LAES can serve as a multichannel or multiplexed electrochemical sensor to detect various analytes on the surface of a single macroscopic substrate. This can be accomplished by separating the substrate into a plurality of areas, preparing the individual areas with different photoactive or biosensitive materials, and then illuminating each area with a light source.…”

Electrochemiluminescence Imaging Based on Bipolar Electrochemistry Using Commercially Available Anisotropic Conductive Films

“…(21) Recently, BPEs have been vertically embedded into thin films, resulting in the densification of electrochemical sensors. (22)(23)(24)(25)(26)(27)(28)(29) One of the films was fabricated by patterning and pyrolyzing SU-8 films. (27) In the 15-µm-thick Parylene C, 1.5 × 10 5 carbon electrodes were embedded.…”

Thermally‐Drawn Multi‐Electrode Fibers for Bipolar Electrochemistry and Magnified Electrochemical Imaging

“…microelectrode-based imaging systems. [31][32][33][34][35][36][37][38][39] Recently, we have developed a bipolar electrochemical microscopy (BEM) based on the closed bipolar electrode (cBPE) with an electrochemiluminescence (ECL) detection system. [33,35,40] The cBPE/ECL system consists of an electrode with its two ends immersed in two different solutions: the measurement solution with analytes of interest and a reporting solution containing luminophores.…”

“…Recently, electrochemical imaging systems leveraging bipolar electrochemistry have emerged as a novel technique that addresses the spatiotemporal issues inherent in SECM and microelectrode‐based imaging systems. [ 31–39 ] Recently, we have developed a bipolar electrochemical microscopy (BEM) based on the closed bipolar electrode (cBPE) with an electrochemiluminescence (ECL) detection system. [ 33,35,40 ] The cBPE/ECL system consists of an electrode with its two ends immersed in two different solutions: the measurement solution with analytes of interest and a reporting solution containing luminophores.…”