Photoelectrochemical surface-enhanced Raman scattering dual-mode aptasensor based on WS₂/Cu-TCPP MOFs Z-scheme heterojunction for microcystin-LR detection

Microcystin-LR (MC-LR), a toxic cyanotoxin, poses severe risks to environmental and human health with its efficient detection urgently required for water safety monitoring. Here, we reported a photoelectrochemical (PEC)-surface-enhanced Raman scattering (SERS) dual-mode aptasensor based on WS 2 /copper(II) meso-tetra(4-carboxyphenyl) porphyrin (WS₂/Cu-TCPP) MOFs Z-scheme heterojunction with a single laser source to produce photocurrent and SERS signals. To access interference between PEC and SERS signals, their correlation was systematically examined by applying a certain bias voltage. This bias voltage drives photogenerated electrons into external circuit, thereby enhancing carrier separation efficiency and suppressing the return of Raman photons to the ground state. In this way, a complementary “PEC-enhancement/SERS-attenuation” signal pattern can be achieved to allow better reliability for biosensing. The presence of ascorbic acid (AA) replicated an identical response to confirm competitive coupling between PEC and SERS derived from WS₂/Cu-TCPP heterojunction. Based on this signal transduction mechanism and localized generated AA by magnetic separation, a dual-mode aptasensor was developed for MC-LR detection with superior sensitivity and interference resistance. It allowed a linear range of 0.01–50 ng mL −1 and a detection limit of 0.14 pg mL −1 for MC-LR as well as high selectivity and stability for real water samples analysis. This work should offer an efficient paradigm for precise analysis of hazardous pollutants in complex matrices.