粘菌素功能化的Fe_(3)O_(4)-GQDs作为荧光探针用于快速检测大肠杆菌

Colistin-functionalized Fe_(3)O_(4)-GQDs as a Fluorescent Probe for Rapid Detection of Escherichia coli

目的:建立一种通过粘菌素功能化的Fe_(3)O_(4)-石墨烯量子点(Colis-Fe_(3)O_(4)-GQDs)荧光探针检测革兰氏阴性细菌-大肠杆菌(Escherichia coli)浓度的分析方法。方法:通过共沉淀法制备了氨基修饰的Fe_(3)O_(4),并将其与含羧基的石墨烯量子点(GQDs)结合,并用粘菌素修饰形成Colis-Fe_(3)O_(4)-GQDs复合物,以此复合物作为荧光探针对不同浓度的大肠杆菌进行检测。结果:大肠杆菌对Colis-Fe_(3)O_(4)-GQDs复合物荧光猝灭效果良好,并且随着菌株浓度的不断增加,其对Colis-Fe_(3)O_(4)-GQDs复合物的荧光猝灭逐渐增强。此方法的检测线性范围为1×10^(2)~10×10^(2) CFU/mL,决定系数为0.999,检测限为0.36×10^(2) CFU/mL。结论:该Colis-Fe_(3)O_(4)-GQDs生物传感器检测方法简单、高效,具有良好的选择性和灵敏度,为革兰氏阴性菌检测提供了新的方法,在细菌检测方面具有广阔的应用前景。

Objective:To establish a method for the determination of Gram-negative bacteria-Escherichia coli by ColisFe_(3)O_(4)-graphene quantum dots(GQDs)functionalized fluorescent probes.Methods:Amino modified Fe_(3)O_(4) was prepared by co-precipitation method,and it was combined with GQDs containing carboxyl groups,and Colis-Fe_(3)O_(4)-GQDs complex was formed by colistin modification.With this complex as fluorescent probe,different concentrations of Escherichia coli were detected.Results:The fluorescence quenching effect of Colis-Fe_(3)O_(4)-GQDs complex was good with Escherichia coli,and the fluorescence quenching of Colis-Fe_(3)O_(4)-GQDs complex was gradually enhanced with the increasing concentration of the strain.The linear detection range of this method was 1×10^(2)~10×10^(2) CFU/mL,the coefficient of determination was 0.999,and the detection limit was 0.36×10^(2) CFU/mL.Conclusion:The colis-Fe_(3)O_(4)-GQDs biosensor is simple and efficient,with good selectivity and sensitivity,which provides a new method for the detection of Gram-negative bacteria,and has a broad application prospect in the detection of bacteria.