A label-free aptasensor based on a fluorescent probe containing styrylbenzothiazole for detection of enrofloxacin

Enrofloxacin (ENR), a third-generation fluoroquinolone antibiotic, poses significant health risks due to potential drug residues in the food chain, necessitating effective monitoring methods. Here, we synthesized a G-quadruplex-targeted fluorescent probe PBTZM containing styrylbenzothiazole. Using this probe, we successfully developed an aptasensor for the detection of ENR by combining it with an ENR aptamer. Under optimal conditions, the aptasensor provided a linear range of 0.001–5 μM and a detection limit of 24.74 nM. In addition, this method showed good performance for ENR detection in river water, milk, serum and urine samples and was further validated by standard HPLC techniques without a significant difference (p > 0.05). It will have great potential in advancing research of quinolone antibiotics and the development of aptamer-based biosensing technologies.