Au Nanoparticle-Decorated TiO2 Nanowires for Surface Plasmon Resonance-Based Photoelectrochemical Bioassays with a Solid–Liquid–Air Triphase Interface

Abstract

Surface plasmon resonance (SPR)-induced photoelectrochemical (PEC) reaction has great potential in developing high-performance bioassay systems. In this study, we report a high-performance visible-light-active SPR-based PEC bioassay system by immobilizing oxidase on Au nanoparticle-decorated superhydrophobic TiO2 nanowire arrays with a solid–liquid–air triphase interface. Based on the triphase bio-photoelectrode, sufficient reactant oxygen can be directly acquired from the air phase with constant and rapid supply, which stabilizes and enhances the kinetics of oxidase catalytic reaction, leading to increased detection accuracy and a wider linear detection range. Moreover, the Au–TiO2 nanowire array-based bio-photoelectrode can be operated under visible light irradiation due to the SPR effect, which improves the stability of PEC bioassay system by avoiding potential deterioration of oxidase molecules in a traditional UV light environment. The SPR-based PEC bioassay with the solid–liquid–air triphase bio-photoanode is an alternative for better disease diagnosis and health monitoring.