A membraneless self-powered photoelectrochemical biosensor based on Bi2S3/BiPO4 heterojunction photoanode coupling with redox cycling signal amplification strategy

The photoelectrochemical (PEC) self-powered system has attracted great attention in disease detection. The determination of a simple and efficient approach for disease-related biomarkers is highly interesting and appealing. Herein, an ingenious visible light-induced membraneless self-powered PEC biosensing platform was constructed, integrating a signal amplification strategy for ultrasensitive split-type PEC bioanalysis. The system was comprised of a Bi2S3/BiPO4 heterojunction photoanode and a platinum (Pt) cathode in a one compartment chamber. An alkaline phosphatase (ALP)-loaded sandwich immunoassay was used to generate the signal reporter ascorbic acid (AA) in a 96-well plate, and myoglobin (Myo) was used as a model protein. In the presence of AA, ferrocene (Fc), and Tris (2-carboxyethyl) phosphine (TCEP), the chemical-chemical redox cycling scheme was operated upon the initial oxidation of Fc by the holes in the Bi2S3/BiPO4 photoelectrode, and Fc was regenerated from Fc(+) by AA. Subsequently, AA was regenerated by TCEP after its oxidation, and cycling was triggered. As a result, the proposed self-powered PEC sensing exhibited excellent performance with a wide linear range from 5.0 x 10 (-13) to 1.0 x 10 (-7) g/mL, and a low detection limit of 2.0 x 10 (-13) g/mL for Myo. This work provided a new design of a redox cycling strategy in the self-powered PEC biosensor, and showed an effective approach for the clinical diagnosis.

Automated summary

An ingenious visible light-induced membraneless self-powered PEC biosensing platform was developed in this study, which showed excellent performance with a wide linear range and low detection limit. The proposed system incorporated a redox cycling strategy for ultrasensitive split-type PEC bioanalysis, providing an effective approach for clinical diagnosis.