Marine Biotechnology and Bioproducts Lab, School of Biosciences and Technology, VIT-Vellore, 632014 Tamil Nadu, India.
Electrodics and Electrocatalysis Division, CSIR - Central Electrochemical Research Institute, Karaikudi 630003, Tamil Nadu, India.
IET Nanobiotechnol. 2020 Dec;14(9):839-850. doi: 10.1049/iet-nbt.2020.0091.
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 from food sample. Magnetosomes were extracted from 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 ( value) on the electrode surface with increase in concentration of LLO protein was confirmed in impedance spectroscopy. The 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 10 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.
李斯特菌病通过污染食物是导致孕妇和新生儿早逝的主要原因之一。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、敏感、特异性和具有成本效益的检测食物样本中的李斯特菌。从 RJS1 中提取磁小体，然后直接与抗李斯特菌溶血素抗体（0.25-1μg/ml）结合，在光谱学中得到证实。李斯特菌溶血素（LLO）蛋白（0.01-7μg/ml）在酶联免疫吸附试验中进行了优化。磁小体与 LLO 抗体（0.25μg/ml）以最佳浓度结合，以检测 LLO 蛋白（0.01μg/ml）。磁小体-LLO 抗体复合物的成本降低了 25%。将磁小体-LLO 抗体复合物直接用外部磁铁固定在丝网印刷电极上。在阻抗光谱学中，随着 LLO 蛋白浓度的增加，电极表面的电阻（R 值）显著增加，得到了证实。对污染牛奶和水样进行处理，并在生物传感器中检测到 LLO 蛋白。交叉反应性试验证实了该生物传感器对其他食源性病原体的特异性。在水和牛奶样本中的检测限为 10CFU/ml，表明了该生物传感器的敏感性。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-抗体复合物的阳性相互作用。
