ホロメソポーラスシリカをベースとしたゲンタマイシン検出用比率蛍光アプタセンサー

Gentamicin (GEN) is an aminoglycoside antibiotic widely used in animal husbandry because of its low cost and high therapeutic efficacy; however, its residues in milk pose a potential risk to food safety. In this study, a truncated aptamer (G41) with high affinity toward GEN was obtained through molecular docking and molecular dynamics simulations. Gold nanoclusters (Au NCs) were synthesized using an l-proline reduction method and conjugated with G41 via Au-S bonds to form Au NCs-Apt. Meanwhile, amino-functionalized hollow mesoporous silica (HMSN-NH₂) was employed as a carrier to load rhodamine 6G (R6G), with Au NCs-Apt acting as a gating molecule to encapsulate R6G through electrostatic interactions.In the presence of GEN, the specific binding between GEN and G41 induced the dissociation of Au NCs-Apt from the surface of HMSN-NH₂, resulting in the release of R6G and a significant enhancement of the fluorescence signal at 556 nm (I₅₅₆), while the fluorescence signal of Au NCs at 442 nm (I₄₄₂) remained essentially unchanged. The proposed sensor exhibited an excellent linear response over the concentration range of 20-4000 ng/mL (R² = 0.9977) with a low detection limit of 2.36 ng/mL. Moreover, The aptasensor showed good repeatability, with relative standard deviations (RSD) below 5% based on three independent measurements (n = 3). In addition, the method was applied to the determination of GEN in spiked milk samples, affording recoveries in the range of 98.35-101.49%, demonstrating its applicability to complex sample matrices. By integrating HMSN with a ratiometric fluorescence aptasensing strategy, this study provides a highly stable and anti-interference analytical platform for the monitoring of antibiotic residues in food.