Introducing cocatalysts into bimetallic sulfides to construct intercalated dual heterojunctions: A photoelectrochemical sensing platform capable of fast PD-L1 response

Abstract

Developing heterojunctions with high visible light absorption capability, fast e-/h+ separation and sufficient chemical stability is crucial for developing efficient photoelectrochemical (PEC) biosensing systems. In this work, we developed an intercalated ZnCdS/NiS/ZnCdS dual heterojunction based on the hydrophilicity of bimetallic sulfides ZnCdS solid solution to construct a PEC immunosensor for PD-L1 detection. Compared with the single-heterojunction system, the configuration of the ZnCdS/NiS/ZnCdS dual heterojunction significantly promotes the effective spatial separation of photo-generated carriers, showing a higher photoelectric conversion capability. The constructed dual heterojunction sensing platform exhibits high sensitivity and selectivity in detecting PD-L1. The sensor showed a good linear range of PD-L1 from 10 fg/mL ∼ 10 ng/mL with a low detection limit of 4.02 fg/mL. It shows the great potential of ZnCdS/NiS/ZnCdS in improving the sensitivity of PEC clinical diagnosis, and the dual heterojunction design opens up new avenues for the construction of multifunctional PEC sensing platforms.