A facile method for foodborne bacterial enrichment and direct identification from milk samples using Janus magnetic mesoporous silica nanoparticles (Janus M-MSNs) is reported. The fluorescent-magnetic nanorods are fabricated using the one-pot sol-gel process, followed by modification with Escherichia coli antibodies to form fluorescent Janus M-MSNs (Janus M-MSNs-Ab). The Janus M-MSNs-Ab combine the fast magnetic response capacity of the magnetic heads with the strong fluorescence and bacterial-targeting properties of the silica bodies, which results in selective capture and fluorescence identification of E. coli from milk samples containing mixed bacteria. After magnetic separation, complexes of the bacteria and nanoparticles are detected through direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), which has a strong, anti-interference performance. Thus, the Janus M-MSNs-Ab synthesized in this study show great sensitivity and effectivity in foodborne bacterial capture and is a promising tool for rapid bacterial detection and investigation when combined with MALDI-TOF-MS.

据报道，使用Janus磁性介孔二氧化硅纳米颗粒（Janus M-MSNs）可以从牛奶样品中进行食源性细菌富集和直接鉴定的简便方法。使用一锅溶胶-凝胶工艺制造荧光磁性纳米棒，然后用大肠杆菌抗体修饰以形成荧光Janus M-MSNs（Janus M-MSNs-Ab）。Janus M-MSNs-Ab结合了磁头的快速磁响应能力与硅胶小体的强荧光和细菌靶向特性，可对大肠杆菌进行选择性捕获和荧光鉴定从含有混合细菌的牛奶样品中提取。磁分离后，可通过直接基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）检测细菌和纳米颗粒的复合物，该复合物具有强大的抗干扰性能。因此，本研究中合成的Janus M-MSNs-Ab在食源性细菌捕获中显示出极大的敏感性和有效性，当与MALDI-TOF-MS结合使用时，是快速进行细菌检测和研究的有前途的工具。