Self-powered photoelectrochemical immunosensor with triple enhanced photoelectric response for sensitive detection of cTnI

Abstract

A self-powered photoelectrochemical (PEC) immunosensor triple enhanced photoelectric response was proposed for the sensitive cardiac troponin (cTnI) detection. The self-powered PEC platform was constructed by sulfur indium copper hollow nanocage as a photocathode and hollow nanometer sphere heterojunction (In2S3 @CdIn2S4) as a photoanode, where the coulomb force of distinct photoelectrodes as the driving force effectively improves the photoelectric response without redox-mediator or external potential. In addition, the reverse transfer of photo-generated charge carriers increases the photoelectric response capacity due to the internal electric field effect in type II heterojunction. What is more exciting is that carefully designed hollow materials playing energy conversion function possess compelling properties. Given the advantages of multiple reflection effects in the cavity, thin-shell configuration and large surface, the designed hollow materials possessed a higher photon capture rate, a shorter-range transfer for photon-generated charges, and more active site points for the associated redox reactions, which facilitated the entire photoelectric response process. Based on the above strategies, the proposed PEC immunosensor achieved triple enhanced photoelectric response to present high sensitivity for detecting cTnI. The present study has gone some way to design nanomaterials with superior photoelectric activity, which paves a way for detecting other disease markers in high sensitivity.