基于量子点的分子灯塔探针的制备及其在DNA探针中的应用

根据荧光共振能量转移理论合成出一种新颖的分子灯塔探针.由于CdTe量子点（QD s）的荧光发射光谱与DABCYL的紫外-可见吸收光谱有很好的重叠性,所以此种探针采用CdTe量子点作为能量给体,DABCYL作为能量受体.通过水相法合成出直径为2.5 nm的CdTe量子点,并且在偶联剂1-乙基-3-（3-二甲基氨丙基）碳二亚氨盐酸盐（EDC）作用下,与5-′NH2-DNA-DABCYL连接得到了分子灯塔探针.实验发现探针的荧光强度相比CdTe-DNA有明显的下降,最大能量转移效率为68.3%,表明CdTe QD s和DABCYL之间发生了荧光共振能量转移.结果表明,此种探针体系对于互补DNA及其变种有着很好的特异性,且其检测极限为5.170×10^-9mol/L.

Preparation of Quantum Dots Conjugated Molecular Beacons and Its Application as DNA Probe

A novel molecular beacons system based on fluorescence resonance energy transfer (FRET) from CdTe quantum dots (QDs) donors to 4-(4′-(dimethylamino) phenylazo) benzoic acid (DABCYL) as energy acceptors was presented in this paper. As the fluorescence emission spectrum of CdTe QDs and the UV-Vis absorption spectrum of DABCYL overlap, CdTe QDs that are 2.5 nm in diameter, as energy donors, were prepared in water and were linked to 5′-NH_2-DNA-DABCYL when 1-ethyl-3-(dimethyla- minopropyl) carbodi-imide hydrochloride (EDC) was existed to get this new molecular beacon. Compared with that of the fluorescence spectrum of CdTe conjugated DNA, the fluorescence intension of molecular beacons decreases significantly with the maximum FRET efficiency of 68.3%, indicating that there is FRET between CdTe QDs and DABCYL. The results indicate that this molecular beacon has a good specificity in distinguishing the complementary DNA and its mutant, and the limit of detection is about 5.170×10~(-9) mol/L.