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【目的】结合纳米技术建立检测大肠杆菌(Escherichiacoli)O157∶H7高灵敏检测技术。【方法】采用化学共沉淀法制备出核心粒径约为10nm的免疫纳米磁颗粒,柠檬酸钠还原法制备粒径约为20nm的免疫胶体金。压电免疫传感器通过金黄色葡萄球菌蛋白A(Protein A from Staphylococcus aureus SPA)法将抗体固定于石英晶振上,两种免疫纳米颗粒借助不同的抗体连接于传感器上对检测频率信号进行放大。【结果】SPA在石英晶振上的最佳固定浓度和时间为1.2mg/mL和40min,抗体的最佳固定浓度和时间为1.0mg/mL和60min。压电免疫传感器通过两种免疫纳米颗粒的放大作用,使其对大肠杆菌O157∶H7的检测限从104cfu/mL提高到101cfu/mL。【结论】免疫纳米颗粒强化对压电免疫传感器的检测频率信号具有很好的放大效应,可以明显提高其检测灵敏度。
【Objective】 The objective of this study was to establish a highly sensitive detection technique for detecting Escherichia coli O157: H7 in combination with nanotechnology. 【Method】 Immunomagnetic nanoparticles with core diameter of about 10 nm were prepared by chemical coprecipitation, and immunogold gold with particle size of about 20 nm was prepared by sodium citrate reduction method. The piezoelectric immunosensor is used to immobilize the antibody on quartz crystal by using Protein A from Staphylococcus aureus SPA. The two kinds of immune nanoparticles are connected to the sensor with different antibodies to amplify the detection frequency signal. 【Result】 The best fixed concentration and time of SPA on quartz crystal were 1.2 mg / mL and 40 min, and the best fixed concentration and time of antibody were 1.0 mg / mL and 60 min. The piezoelectric immunosensor enhanced the detection limit of E. coli O157: H7 from 104cfu / mL to 101cfu / mL by the amplification of two kinds of immune nanoparticles. 【Conclusion】 Immune nanoparticle enhancement has a good amplification effect on the detection frequency of piezoelectric immunosensor, which can significantly improve the detection sensitivity.