基于量子点和磁珠的大肠埃希菌O157∶H7检测研究

Detection of Escherichia coli O157: H7 based on quantum dot and magnetic bead

目的构建一种基于量子点和磁珠的大肠埃希菌O157∶H7的检测方法。方法以亲和素化磁珠结合生物素化的抗体制备修饰有大肠埃希菌O157∶H7抗体的磁珠,该磁珠可从检测体系中捕获大肠埃希菌O157∶H7,依次加入生物素化大肠埃希菌O157∶H7抗体、亲和素化Cd Se量子点后,分别经磁分离弃去未结合的分子,通过溶液的荧光吸收光谱的改变定量检测该菌。结果该方法特异性好,只有大肠埃希菌O157∶H7呈阳性反应,其余对照菌株均无明显反应;随着大肠埃希菌O157∶H7浓度的增大,655 nm处荧光值也逐步升高;并在1 h内实现对104cfu/ml的菌液的检测。结论本实验建立的这种方法检测时间短,结果易于判断,具有良好的临床应用前景。

Objective A method of Escherichia coli O157：H7 detection based on quantum dot and magnetic bead was devel- oped in this work. Methods Magnetic bead modified with Escherichia eoli O157 ：H7 antibody through the avidin - biotin inter- aetion can capture the target cell in the solution, then adding biotinylated Escherichia coli O157 ：H7 antibody and avidin -modi- fied CdSe quantum dot into the solution, unconjugated molecule can be discarded respectively by magnetic separation. Quantita- tive detection of Escherichia coli O157 ： H7 was obtained through the change of fluorescence spectroscopy. Results This method was of good use, and only the Escherichia coli O157：H7 had positive reaction, the control strains had no obvious reaction. With the increase of Escherichia coli O157：H7 concentration, 655 nm fluorescence value also gradually increased. This method can detect 104 CFU/ml Escherichia coli O157 ： H7 in 1 hour with high specificity. Conclusion This method has features of short detection time and simple result judgment, so it is potentially valuable in application.