In this work, a sandwich fluorometric method for dual-role recognition of L. monocytogenes was developed based on antibiotic-affinity strategy and fluorescence quenching effect for sensitive and rapid detection of L. monocytogenes in ham samples. Vancomycin (Van) was conjugated with magnetic nanoparticles (MNPs) to recognize and capture target bacteria. Biotinylated aptamers were used to bind specifically to L. monocytogenes through the cell wall. The two agents recognized target bacteria at different binding sites showing satisfied specificity. The upconversion fluorescence response signal could be enlarged by using the inner filter effect (IFE) between the colored products produced by enzyme-catalyzing substrate and upconversion nanoparticles (UCNPs). The change in fluorescence intensity could represent the concentration of target bacteria over 10²–2 × 10⁸ CFU mL⁻¹. The developed sandwich fluorimetric method achieved a low detection limit (LOD) of 2.8 × 10² CFU mL⁻¹. Overall, the constructed fluorometric sensor could provide a simple and reliable method for the detection of L. monocytogenes.

在这项工作中，基于抗生素亲和策略和荧光猝灭效应，开发了一种用于双角色识别单核细胞增生李斯特菌的夹心荧光法，用于灵敏、快速地检测火腿样品中的单核细胞增生李斯特菌。万古霉素 (Van) 与磁性纳米粒子 (MNP) 结合以识别和捕获目标细菌。生物素化适体用于特异性结合单核细胞增生李斯特菌穿过细胞壁。这两种试剂识别不同结合位点的目标细菌，表现出令人满意的特异性。利用酶催化底物产生的有色产物与上转换纳米粒子（UCNPs）之间的内滤效应（IFE）可以放大上转换荧光响应信号。荧光强度的变化可以代表目标细菌的浓度超过 10 ² –2 × 10 ⁸  CFU mL ^-1。所开发的夹心荧光法实现了 2.8 × 10 ²  CFU mL ^-1的低检测限 (LOD) 。总体而言，构建的荧光传感器可以提供一种简单可靠的检测单核细胞增生李斯特菌的方法。