量子点双标记的Fe3O4@Au磁性纳米DNA电致发光型传感器

合成了Fe3O4@Au磁性纳米粒子,并根据单链寡聚核苷酸(ss-DNA)杂交原理,利用量子点电化学发光,构建了DNA电化学传感器.在磁控玻碳电极(MCGCE)表面,将5′-SH-ssDNA捕获探针自组装在Fe3O4@Au磁性纳米粒子上,然后与目标DNA互补的一端杂交形成dsDNA,再与双标记了量子点的5′-NH2-ssDNA-NH2-3′信号探针杂交形成三明治杂交的DNA.应用循环伏安法对DNA的固定与杂交进行了表征.目标DNA浓度在1.0×10-13～1.0×10-11 mol/L范围与其响应的ECL信号呈线性关系,检出限为1.8×10-14mol/L.由于采用量子点双标记法,检测的灵敏度显著提高.

Electroluminescence Biosensor for DNA Determination Based on CdTe Quantum Dots Double-Tagging Fe3O4@Au Core/Shell Magnetic Nanoparticles

An electrochemiluminescence(ECL) DNA biosensor based on Fe3O4@Au core/shell nanoparticle films modified magnetic controlled glassy carbon electrode(MCGCE) was developed by using quantum dots(QDs) as labels of reporter probe DNA.The DNA biosensor was based on a sandwich detection strategy,which involves 5′-SH capture probe immobilized on magnetic nanoparticles(MNPs),target and 5′-NH2 reporter probe NH2-3′.After hybridization reaction,thioglycollic acid-capped CdTe QDs are attached to the end amino group of the sandwich hybrids.The fabrication and hybridization process of the DNA biosensor were characterized by cyclic voltammetric methods.The responsive ECL intensity was linearly related to the target nucleic acid concentration in the range of 1.0×10-13 to 1.0×10-11 mol/L,with a detection limit of 1.8 ×10-14mol/L.In addition,the ECL biosensor exhibited the advantages of high sensitivity,good selectivity,satisfying stability,reproducibility and repeatability.