Hydrovoltaic-photoelectric coupling effect boosted self-powered aptasensor for on-site and ultrasensitive monitoring of enrofloxacin in aquaculture products based on CdS/ZIF-67 heterojunctions.

On-site monitoring of antibiotic residues in aquaculture products is of great significance for providing instant content information to protect food safety and human health. In this work, a novel hydrovoltaic self-powered electrochemical sensor was fabricated for real-time sensitive detection of enrofloxacin (ENR) by integration of photoelectric effect based on CdS/cobalt-based metal-organic framework (ZIF-67) nanocomposites. The CdS/ZIF-67 heterojunction architecture facilitated the simultaneous harvesting of light and moisture energy, owing to its abundant charge carriers, excellent ion transport properties, and high-efficiency photoelectric conversion. Furthermore, the built-in electric field at the CdS/ZIF-67 interface enhanced charge separation and transfer, while light irradiation promoted water evaporation and ion migration, significantly boosting the hydrovoltaic output. Consequently, this hydrovoltaic-photoelectric coupling effect enabled sustainable and amplified electrical signal generation without an external power supply, yielding outputs approximately 6.8 and 5.7 times greater than those of pure CdS and ZIF-67, respectively. The designed platform was integrated with split aptamers to construct a highly sensitive and specific self-powered sensor for ENR detection through target-induced signal modulation, which displayed a wide linear detection range (1 × 10-14 M ∼ 1 × 10-8 M) and a low detection limit of 1.46 × 10-15 M. By leveraging enhanced signal output and minimized background interference from the split aptamer design, this system demonstrates great potential for real-time, on-site monitoring in environmental, agricultural, and food safety applications.