NiS2/NiFe LDH/g-C3N4 ternary heterostructure-based label-free photoelectrochemical aptasensing for highly sensitive determination of enrofloxacin

Photoelectrochemical (PEC) aptasensor based on photoactive species with remarkable and stable PEC response is a rising analytical method to implement highly efficient and sensitive detection of residual antibiotics in the field of food. Herein, NiS2/NiFe-layered double/graphitic carbon nitride (NiS2/NiFe LDH/g-C3N4) ternary heterostructure designed by the surface vulcanization of flower-like NiFe LDH/g-C3N4 was used for developing a label-free PEC aptasensing platform to detect enrofloxacin (ENR). The introduction of NiS2 with narrow bandgap can strengthen the light harvesting of solar energy, producing large amounts of photoinduced carriers. NiS2 as the electrons conduction bridge further accelerates the transmission efficiency of electrons in contrast to binary heterojunction, endowing ternary heterostructure with superior photocurrent signal. A label-free PEC aptasensor detected ENR with an amplified detection signal because of the oxidation of ENR molecules by photoinduced holes. This PEC aptasensing platform of ENR manifested a wide detection range from 3.6 × 10−7 to 30 ng/mL with a low detection limit of 1.2 × 10−7 ng/mL as well as can provide a sensitive and stable analysis with feasible application to monitor milk and honey samples. This design can open the utilization of ternary heterostructure by surface vulcanization to improve the sensitivity of PEC aptasensing platform for monitoring environmental pollutants.