AUTHOR=Xiao Hui-Jin , Liao Xiao-Jing , Wang Hui , Ren Shu-Wei , Cao Jun-Tao , Liu Yan-Ming 

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

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.845617

DOI=10.3389/fchem.2022.845617

ISSN=2296-2646

ABSTRACT=A novel signal increased photoelectrochemical (PEC) biosensor for L-cysteine (L-Cys) was proposed based on Bi2MoO6-Bi2S3 heterostructure formed in situ on indium-tin oxide (ITO) electrode. To fabricate the PEC biosensor, Bi2MoO6 nanopartciles 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 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 photoinduced 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 broaden the application of the PEC bioanalysis based on in situ formation of photoactive materials.