A miniature self-powered electrochemical sensor for the determination of patulin based on an integrated photocatalytic fuel cell

Unlike traditional electrochemical sensor relying on an external electric supply, self-powered electrochemical sensor (SPES) uses the electric signal from the output generated from itself and thus is favorable to achieve the miniaturization of device. Herein, we designed an integrated photocatalytic fuel cell (PFC) to construct a miniature SPES for patulin (PAT) detection. In this design, a graphene-Bi2S3 (G-Bi2S3) photoanode and a Prussian blue (PB) cathode were fabricated on a single etched ITO slice to construct an integrated PFC. Under visible light illumination, photogenerated electrons on the G-Bi2S3 photoanode flowed through the circuit into PB cathode to reduce PB, leading to the generation of electric output in PFC. By utilizing the inhibited PFC output originated from the capture of PAT by aptamer immobilized on the photoanode, a miniature SPES for PAT driven by visible light was realized. The proposed SPES exhibits a wide dynamic range toward PAT in the concentration range from 5.0 nM to 500 nM. And the detection limit (3 S/N) was down to 0.28 nM. The proposed SPES was successfully applied to the detection of PAT in apple juice.