微生物检测中糖量子点的制备及其与凝集素的相互作用

Preparation of glyco-quantum dots for microbial detection

为了以量子点为探针建立简便快速的病原微生物检测方法,采用配体交换法将具有微生物特异性的糖链偶联到CdSeS/ZnS量子点表面,制备2种糖量子点复合材料(甘露糖-量子点和半乳糖-量子点)。通过对它们的结构、物性和光谱学特性进行表征,结果显示:2种糖量子点均具有良好的水溶性、荧光发射和紫外-可见光吸收性能。进一步以这2种糖量子点为探针与凝集素共孵育后,溶液颜色和荧光发射光谱的变化表明:甘露糖-量子点对刀豆蛋白具有特异性,最低可检测浓度为95 nmol/L;而半乳糖-量子点对蓖麻毒素具有特异性,最低可检测浓度为3 nmol/L。因为细菌和病毒表面的粘附素多为凝集素类蛋白,本研究为进一步建立病原微生物的检测方法奠定了基础。

Carbohydrates with the binding capability to microbes were coupled with luminescent quantum dots（QDs） for microbial detections.Mannose and galactose-coated QDs（Man-QDs and Gal-QDs） were prepared using the thiolated sugars to replace the original ligands（mercaptoacetic acid） on the surface of CdSeS/ZnS QDs,according to a ligand exchange method.Structural and spectral characterizations of the resulting glyco-QDs revealed intense luminescent emission and UV-visible absorption,as well as high solubility and stability in water.Further studies on interactions between the glyco-QDs and corresponding lectins（ConA and RCA120） demonstrated that luminescent aggregations of the lectins caused by the multiple and specific bindings with the glyco-QDs could occur at nanomolar concentrations in a very short time（90 min）,This indicated the potentials of the glyco-QDs for rapid and sensitive biosensings.As the lectin-like adhesins are commonly found on the surfaces of many kinds of microbes,the present work provides a baseline for the future studies on microbial detections with the glyco-QDs probes.