水相合成了谷胱甘肽(GSH)修饰的CdTe 量子点(QDs). 在PH＝7.4的Tris-HCl缓冲溶液中, 吖啶橙(AO)通过静电引力吸附到GSH-CdTe QDs 的表面, 与GSH-CdTe QDs形成了基态复合物, 导致GSH-CdTe QDs的荧光猝灭. 在GSH-CdTe QDs-AO体系中加入小牛胸腺DNA (ctDNA), ctDNA诱导AO从GSH-CdTe QDs表面脱落嵌入其双螺旋结构中, 导致GSH-CdTe QDs的荧光恢复. 根据GSH-CdTe QDs荧光的猝灭和恢复, 实现了量子点荧光的可逆调控. ctDNA引起GSH-CdTe QDs-AO体系荧光恢复强度与ctDNA浓度成良好的线性关系, 检出限为0.13 ng•mL^－1, 据此提出了简便快捷、准确、高灵敏测定ctDNA的新方法. 还结合共振瑞利散射(RRS)光谱、吸收光谱和原子力显微镜照片研究了GSH-CdTe QDs-AO-ctDNA三者之间的相互作用, 对相互作用机理进行了讨论并提出了相应的作用模型.

Glutathione (GSH)-capped CdTe quantum dots (GSH-CdTe QDs) were synthesized in aqueous solution. In pH 7.4 Tris-HCl buffer medium, acridine orange (AO) was adsorbed to the surfaces of GSH-CdTe QDs via electrostatic attraction and formed ground state complex, which resulted in the quenching of the fluorescence of GSH-CdTe QDs. Adding ctDNA to GSH-CdTe QDs-AO system leaded to the fluorescence intensity of GSH-CdTe QDs recover, which can be explained by that the addition of ctDNA to the system induced AO to dissociate from the surface of GSH-CdTe QDs and embed into its double helix structure. According to the fluorescence quencher and restoration for GSH-CdTe QDs, fluorescence reversible control of QDs was realized. The fluorescence intensity change of GSH-CdTe QDs-AO system aroused by the addition of ctDNA was proportional to the ctDNA concentration in a certain range, and its detection limit was 0.13 ng•mL^－1. Based on it, the simple, rapid, accurate and sensitive methods had been proposed to determine ctDNA. The interaction of GSH-CdTe QDs-AO-ctDNA was studied by resonance Rayleigh scattering (RRS), absorption spectra and image of atomic force microscopy. The interaction mechanism was discussed and corresponding model of interaction was built.