Electroanalytical and Bioelectroanalytical Systems Based on Metal and Semiconductor Nanoparticles

TLDR

Metal, semiconductor, and magnetic nanoparticles serve as functional units that enhance electroanalytical applications. The authors aimed to harness these nanoparticle functions to create electrochemical gas sensors, functionalized nanoparticle‑based sensors, and various biosensors such as enzyme, immuno, and DNA sensors. By using metal nanoparticles to roughen electrode surfaces, catalyze reactions, amplify signals, and act as dissolvable labels that can be stripped; semiconductor nanoparticles to enable photoelectrochemical detection; and magnetic particles to separate biorecognition complexes and amplify signals while an external magnet switches electrocatalytic processes, the authors constructed versatile electroanalytical platforms. Studies showed that enzyme‑mediated reactions and DNA hybridization generate measurable photocurrents, confirming the effectiveness of the photoelectrochemical detection strategy.

Abstract

Abstract Metal, semiconductor and magnetic particles act as functional units for electroanalytical applications. Metal nanoparticles provide three important functions for electroanalysis. These include the roughening of the conductive sensing interface, the catalytic properties of the nanoparticles permiting their enlargement with metals and the amplified electrochemical detection of the metal deposits and the conductivity properties of nanoparticles at nanoscale dimensions that allow the electrical contact of redox‐centers in proteins with electrode surfaces. Also, metal and semiconductor nanoparticles provide versatile labels for amplified electroanalysis. Dissolution of the nanoparticle labels and the electrochemical collection of the dissolved ions on the electrode followed by the stripping‐off of the deposited metals represents a general electroanalytical procedure. These unique functions of nanoparticles were employed for developing electrochemical gas sensors, electrochemical sensors based on molecular‐ or polymer‐functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme‐based electrodes, immunosensors and DNA sensors. Semiconductor nanoparticles enable the photoelectrochemical detection of analytes. Several studies have revealed the photocurrent generation by enzyme‐mediated processes and as a result of DNA hybridization. Magnetic particles act as functional components for the separation of biorecognition complexes and for the amplified electrochemical sensing of DNA or antigen/antibody complexes. Also, electrocatalytic and bioelectrocatalytic processes at electrode surfaces are switched by means of functionalized magnetic particles and in the presence of an external magnet.