Listeriosis through contaminated food is one of the leading causes of premature deaths in pregnant women and new born babies. Here, the authors have developed a magnetosomes-based biosensor for the rapid, sensitive, specific and cost-effective detection of Listeria monocytogenes from food sample. Magnetosomes were extracted from Magnetospirillum sp. RJS1 and then directly bound to anti-Listeriolysin antibody (0.25-1 µg/ml), confirmed in spectroscopy. Listeriolysin (LLO) protein (0.01-7 µg/ml) was optimised in enzyme-linked immunosorbent assay. Magnetosomes was conjugated with LLO antibody (0.25 µg/ml) in optimum concentration to detect LLO protein (0.01 µg/ml). Magnetosomes-LLO antibody complex was 25% cost effective. The magnetosomes-LLO antibody complex was directly stabilised on screen printed electrode using external magnet. The significant increase in resistance (RCT value) on the electrode surface with increase in concentration of LLO protein was confirmed in impedance spectroscopy. The L. monocytogenes contaminated milk and water sample were processed and extracted LLO protein was detected in the biosensor. The specificity of the biosensor was confirmed in cross-reactivity assay with other food pathogens. The detection limit of 101 Cfu/ml in both water and milk sample manifests the sensitive nature of the biosensor. The capture efficiency and field emission scanning electron microscopy confirmed positive interaction of Listeria cells with magnetosomes-antibody complex.

中文翻译：

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基于磁小体的生物传感器的开发，用于检测食品样品中的单核细胞增生李斯特菌。

通过受污染的食物引起的李斯特菌病是导致孕妇和新生儿过早死亡的主要原因之一。在这里，作者开发了一种基于磁小体的生物传感器，用于快速、灵敏、特异性和经济高效地检测食品样品中的单核细胞增生李斯特菌。磁小体是从 Magnetospirillum sp 中提取的。RJS1 然后直接与抗李斯特菌溶血素抗体 (0.25-1 µg/ml) 结合，在光谱学中得到证实。在酶联免疫吸附试验中优化了李斯特菌溶血素 (LLO) 蛋白 (0.01-7 µg/ml)。磁小体与最佳浓度的 LLO 抗体 (0.25 µg/ml) 结合以检测 LLO 蛋白 (0.01 µg/ml)。Magnetosomes-LLO 抗体复合物的成本效益为 25%。使用外部磁铁将磁小体-LLO 抗体复合物直接稳定在丝网印刷电极上。阻抗谱证实了随着 LLO 蛋白浓度的增加，电极表面的电阻（RCT 值）显着增加。处理受单核细胞增生李斯特菌污染的牛奶和水样，并在生物传感器中检测到提取的 LLO 蛋白。生物传感器的特异性在与其他食物病原体的交叉反应测定中得到证实。水和牛奶样品中 101 Cfu/ml 的检测限体现了生物传感器的灵敏性。捕获效率和场发射扫描电子显微镜证实了李斯特菌细胞与磁小体-抗体复合物的正相互作用。处理受单核细胞增多症污染的牛奶和水样，并在生物传感器中检测到提取的 LLO 蛋白。生物传感器的特异性在与其他食物病原体的交叉反应测定中得到证实。水和牛奶样品中 101 Cfu/ml 的检测限体现了生物传感器的灵敏性。捕获效率和场发射扫描电子显微镜证实了李斯特菌细胞与磁小体-抗体复合物的正相互作用。处理受单核细胞增多症污染的牛奶和水样，并在生物传感器中检测到提取的 LLO 蛋白。生物传感器的特异性在与其他食物病原体的交叉反应测定中得到证实。水和牛奶样品中 101 Cfu/ml 的检测限体现了生物传感器的灵敏性。捕获效率和场发射扫描电子显微镜证实了李斯特菌细胞与磁小体-抗体复合物的正相互作用。