Construction of a photoelectrochemical immunosensor based on CuInS2 photocathode and BiVO4/BiOI/Ag2S photoanode and sensitive detection of NSE

In this paper, a photoelectrochemical (PEC) immunosensor was constructed to detect neuron-specific enolase (NSE) with ITO/BiVO4/BiOI/Ag2S as photoanode and ITO/CuInS2 as photocathode. Due to its excellent photocurrent response, Ag2S sensitized BiVO4/BiOI composite was selected to provide stable photocurrent in place of the traditional Pt electrode. ITO/CuInS2 electrode was used to immobilize biomolecules, which solved the deficiency of poor anti-interference ability of single photoanode. Under the optimal experimental conditions, the PEC immunosensor had outstanding linear relationship within the range of NSE concentration from 5 pg/mL-200 ng/mL, and the detection limit was 1.2 pg/mL. The constructed PEC immunosensor had two advantages. On the one hand, the PEC immunosensor was built on the photocathode, which had better anti-interference ability because of the separation of light capture and biomolecular recognition process. On the other hand, the introduction of photoanode increased the photocurrent response and reduced the detection limit of target antigen. The PEC immunosensor had good stability, reproducibility and specificity, and provided a broad prospect for the detection of other molecules.