Multi-interface high-entropy sulfide combining with methylene blue sensitization and cyclic enzymatic cleavage...

A novel photoelectrochemical (PEC) aptasensor based on high-entropy sulfide (CdZnMnCrCo)_xS for ultrasensitive ampicillin (AMP) detection has been developed. The sulfide, synthesized by a simple one-pot solvothermal method, featured abundant heterointerfaces and rich grain boundaries, which enhanced charge separation/transport, amplifying the PEC signals. Integrated with methylene blue (MB, as a photosensitizer) and exonuclease Exo-1-mediated recycling, the sensor achieved a broad linear range (0.1-1×10⁶ pg mL^-1) and a low detection limit (0.09 pg mL^-1) with strong anti-interference characteristic. Spike-recovery tests on actual water samples at 10 and 50 pg mL^-1 produced excellent recoveries of 97.4-103.8%. This work highlights the high-entropy sulfide's potential as versatile sensing platforms for advancing PEC-based environmental monitoring. Future research will integrate multiplexed aptamer arrays with flexible printable electrodes for on-site detection in medical wastewater.