In Situ Formation of Bi₂MoO₆-Bi₂S₃ Heterostructure: A Proof-Of-Concept Study for Photoelectrochemical Bioassay of l-Cysteine.

ABSTRACT: A novel signal-increased photoelectrochemical (PEC) biosensor for l-cysteine (L-Cys) was proposed based on the Bi₂MoO₆-Bi₂S₃ heterostructure formed in situ on the indium-tin oxide (ITO) electrode. To fabricate the PEC biosensor, Bi₂MoO₆ nanoparticles were prepared by a hydrothermal method and coated on a bare ITO electrode. When L-Cys existed, Bi₂S₃ was formed in situ on the interface of the Bi₂MoO₆/ITO electrode by a chemical displacement reaction. Under the visible light irradiation, the Bi₂MoO₆-Bi₂S₃/ITO electrode exhibited evident enhancement in photocurrent response compared with the Bi₂MoO₆/ITO electrode, owing to the signal-increased sensing system and the excellent property of the formed Bi₂MoO₆-Bi₂S₃ heterostructure such as the widened light absorption range and efficient separation of photo-induced electron-hole pairs. Under the optimal conditions, the sensor for L-Cys detection has a linear range from 5.0 × 10^-11 to 1.0 × 10^-4 mol L^-1 and a detection limit of 5.0 × 10^-12 mol L^-1. The recoveries ranging from 90.0% to 110.0% for determining L-Cys in human serum samples validated the applicability of the biosensor. This strategy not only provides a method for L-Cys detection but also broadens the application of the PEC bioanalysis based on in situ formation of photoactive materials.

SUBMITTER: Xiao HJ 

PROVIDER: S-EPMC9158332 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature