纳米免疫磁颗粒检测大肠埃希菌O157：H7

Preparation of immunomagnetic nanoparticles and application in detection of E.coli O157:H7

目的制备一种表面包被有大肠埃希菌O157：H7多克隆抗体的纳米级葡聚糖免疫磁颗粒,在检测大肠埃希菌O157：H7的同时,对磁颗粒的应用条件进行优化。方法FeCl3和FeCl2在氨水条件下与葡聚糖反应生成纳米葡聚糖磁颗粒,利用高碘酸钠将其氧化后,在表面包被上大肠埃希菌O157：H7多克隆抗体,制成纳米免疫磁颗粒进行检测。结果该方法可在15 min内完成对样品的分离,检测限为101CFU/ml甚至更少,当样品中含有108CFU/ml的杂菌时,检测限为101-102CFU/ml,杂菌对检测结果影响甚微。结论利用纳米级葡聚糖免疫磁颗粒分离目的菌是一种灵敏度高、特异性强、操作简便的有效方法。

Objective To prepare a kind of magnetic iron-dextran nanoparticles that was coated with anti-E, coli O157： H7 IgG, and to establish the optimum conditions of magnetic nanoparticles application for the detection of E. coli O157 ： H7. Methods Magnetic iron-dextran nanoparticles were prepared by reacting a mixture of ferric and ferrous ions with dextran polymers under alkaline conditions. The particles were coated with antiserum against E. coli O157 ： H7 by the periodate oxidation-borohydride reduction procedure. Finally, the immunomagnetic nanoparticles were prepared for the detection. Results E. coli O157：H7 could be isolated from samples within 15 rain with the sensitivity of 101 CFU/ml or even less. In the presence of 108 CFU/ml other organisms, the sensitivity was 101-102 CFU/ml. Nonspecfie bacterium showed very weak influence on detection results. Conclusion Isolation of target bacteria by immunomagnetic nanoparticles is an efficient method with high sensitivity and specificity.