Fluorescent molecularly imprinted sensor for rapid detection of gentamicin in Milk

Gentamicin, a widely used veterinary antibiotic in animal husbandry, poses significant food safety risks due to its persistence in livestock products, soil, and water systems. Chronic exposure to gentamicin residues is associated with severe health effects, including ototoxicity, nephrotoxicity, and neuromuscular toxicity. To address this challenge, we developed a fluorescent sensing strategy by synthesizing a core–shell nanocomposite, Fe₃O₄@SiO₂@N-GQDs@MIPs (termed the MIPs probe). This probe was constructed by integrating nitrogen-doped graphene quantum dots (N-GQDs) with magnetic Fe₃O₄ nanoparticles, and the overall detection platform is referred to as the MIP sensor. The sensor operates via static quenching, enabling specific and sensitive detection of gentamicin with a linear range of 3–900 nM and a detection limit of 0.274 nM. The sensor was successfully applied to detect gentamicin in milk samples, demonstrating excellent recovery rates (94.0–103.3%) and precision (RSD < 2.2%). This work presents a robust, efficient, and field-deployable platform for monitoring antibiotic residues in food products, offering significant improvements over conventional chromatographic and immunological methods.