A self-powered photoanode-supported photoelectrochemical immunosensor for CYFRA 21-1 detection based on In2O3/In2S3/CdIn2S4 heterojunction

A self-powered photoanode-supported photoelectrochemical (PEC) immunosensor was designed based on In2O3/In2S3/CdIn2S4 as photoanode and [email protected] as biocathode for the detection of CYFRA 21–1. In this proposal, In2O3/In2S3/CdIn2S4 heterojunction modified indium-tin oxide (ITO) electrode was served as a substitute for platinum (Pt) counter electrode to provide an evident and stable photocurrent signal. The matched band structure of In2O3, In2S3 and CdIn2S4 as well as the unique hollow porous structure of In2O3/In2S3/CdIn2S4 played a pivotal role in accelerating the separation and transfer of photocarrier. Meanwhile, [email protected] with excellent conductivity further enhanced the photocurrent which was provided by photoanode In2O3/In2S3/CdIn2S4 heterojunction. Besides, PDA could effectively capture the antibody (Ab) through Michael addition. Separating photoanode from the sensing biocathode was conducive to improve the anti-interference capability of PEC sensor because the reductive species in biologic media will change PEC properties of the photoanode interface. Under optimal conditions, the PEC immunosensor have realized the detection of CYFRA 21–1 (0.5 pg/mL - 50 ng/mL) and the detection limitation with 0.16 pg/mL. In addition, the proposed self-powered PEC sensor with acceptable selectivity, reproducibility, and stability provide a new horizon for designing PEC immunosensing platform in bioassays.