Self-powered molecular imprinted photoelectrochemical sensing platform of sialic acid employing WO3/Bi2S3 photoanode and CuInS2 photocathode

A dual-photoelectrode molecular imprinted photoelectrochemical (PEC) sensor is first built for the determination of sialic acid (SA) without additional energy supply. Specifically, WO3/Bi2S3 heterojunction behaves as a pho-toanode to provide amplified and stable photocurrent for the PEC sensing platform, which is attributed to the matched energy levels of WO3 and Bi2S3 promoting the electron transfer and improving photoelectric conversion properties. CuInS2 micro-flowers functionalized by molecularly imprinted polymers (MIPs) are served as photocathode to recognize SA, avoiding the deficiency of high production cost and poor stability from biological enzymes, aptamers, or antigen-antibodies. The inherent deviation between the Fermi level of the photoanode and the photocathode guarantees a spontaneous power supply for the PEC system. Benefiting from the photoanode and recognition elements, the as-fabricated PEC sensing platform has a strong anti-interference ability and high selectivity. Moreover, the PEC sensor displays a wide linear range of 1 nM-100 mu M and a low detection limit of 7.1 x 10-10 M (S/N = 3) based on the relationship between photocurrent signal and SA concentration. Accordingly, this research provides a new and valuable approach to detecting various molecules.

Automated summary

A dual-photoelectrode molecular imprinted photoelectrochemical (PEC) sensor is developed for the determination of sialic acid (SA) without requiring additional energy supply. The sensor utilizes a WO3/Bi2S3 heterojunction as the photoanode to provide stable and amplified photocurrent, while CuInS2 micro-flowers functionalized with molecularly imprinted polymers (MIPs) serve as the photocathode for recognizing SA. The PEC sensor exhibits a wide linear range, high selectivity, and a low detection limit, making it a valuable approach for detecting various molecules.