Abstract The monitoring and control of foodborne pathogenic microorganisms to protect food safety is of great significance. A biosensor based on superparamagnetic ultra-small iron oxide nanoparticles (USIO NPs) combined with membrane filtration and low field nuclear magnetic resonance (LF-NMR) for rapid detection of Salmonella is introduced. First, free biotin-capture-antibodies and biotin-detection-antibodies were specifically bound to different targets of Salmonella in milk samples. Then streptavidin-coated USIO NP probes were coupled with the biotinylated monoclonal antibody to capture Salmonella. Finally, polyethersulfone membrane filtration was performed on the final reaction system to remove unbound-probes, and the transverse magnetisation time (T2) of the filtrate was measured by NMR to indirectly reflect the content of the target substance retained on the filter membrane. This method shows high specificity and anti-interference to Salmonella, and the limit of detection (LOD) in pure culture and real samples was 2.3 × 103 cfu mL−1 within 150 min.

中文翻译：

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基于超小型氧化铁纳米生物传感器的牛奶中沙门氏菌核磁共振快速检测

摘要 食源性病原微生物的监测和控制对保障食品安全具有重要意义。介绍了一种基于超顺磁性超小氧化铁纳米粒子 (USIO NPs) 结合膜过滤和低场核磁共振 (LF-NMR) 的生物传感器，用于快速检测沙门氏菌。首先，游离的生物素捕获抗体和生物素检测抗体与牛奶样品中沙门氏菌的不同靶点特异性结合。然后将链霉亲和素包被的 USIO NP 探针与生物素化单克隆抗体偶联以捕获沙门氏菌。最后，对最终反应体系进行聚醚砜膜过滤以去除未结合的探针，滤液的横向磁化时间（T2）通过核磁共振测量，间接反映滤膜上截留的目标物质的含量。该方法对沙门氏菌具有高特异性和抗干扰性，纯培养物和真实样品的检出限 (LOD) 在 150 分钟内为 2.3 × 103 cfu mL-1。