Dual-mode visible light-induced aptasensing platforms for bleomycin detection based on CdS–In2S3 heterojunction

CdS–In 2 S 3 heterojunction with enhanced photoelectrochemical (PEC) performance was synthesized to construct dual-mode visible light-induced biosensors for highly sensitive and selective detection of bleomycin (BLM). Due to improved absorption in the visible region and suppressed recombination of electron-hole pairs in the heterojunction, CdS–In 2 S 3 composite exhibited enhanced photocurrent response under visible light illumination. Using CdS–In 2 S 3 as photoactive materials and BLM-binding aptamer as recognition element, a PEC aptasensor displaying a declined photocurrent response to BLM was facilely constructed, which was linear to BLM concentration in the range of 5.0–250 nM. On the other hand, the CdS–In 2 S 3 photoanode was employed to construct a photofuel cell (PFC). In such a PFC, the oxidation of water on CdS–In 2 S 3 photoanode under visible light illumination and the reduction of oxygen on Pt cathode led to the generation of electricity. When BLM-binding aptamer was immobilized on CdS–In 2 S 3 photoanode, the output power of the PFC was inversely proportional to the logarithm of BLM concentration from 10 to 250 nM, offering a visible light-induced self-powered sensing platform for BLM detection. Both of the proposed sensors showed high selectivity , good reproducibility and high stability. They were successfully applied to the determination of BLM in human serum samples.