High-performance self-powered photoelectrochemical bioassay system with a triphase oxidase enzymatic interface

Abstract

In the field of biomolecule detection, self-powered photoelectrochemical (PEC) bioassay devices have gained considerable interest with no demand for an external voltage but rather solar energy consumption. In this study, we present a self-powered PEC bioassay system that consists of a nanoporous BiVO4 photoanode coupled to a biophotocathode with a solidliquidair triphase oxidase enzymatic interface. The triphase biophotocathode was assembled by immobilizing oxidase on superhydrophobic Cu2O@TiO2 nanowire arrays. A high and steady interfacial oxygen concentration can be ensured by the triphase biophotocathode with much increased gas mass transport capability, which consequently enhance the kinetics of the oxidase enzymatic reaction as well as the sensing performance of self-powered PEC bioassay system. For the diphase biophotocathode based system, the low solubility and slow diffusion rate of oxygen restrict the kinetics of the oxidase catalytic reaction. As a result, the proposed triphase self-powered PEC bioassay platform exhibits excellent performance with a linear range up to 20 mM for glucose (a model analyst) detection, which is 20 times higher than that of the diphase one. Furthermore, an exceptional anti-interface is obtained by the cathodic bioanalysis approach in the self-powered PEC bioassay system.