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配体对CdTe量子点与BSA的选择性相互作用的影响

ISSN号：0251-0790
期刊名称：《高等学校化学学报》
时间：0
分类：O657.3[理学—分析化学;理学—化学]
作者机构：[1]南京大学化学化工学院,生命分析化学国家重点实验室,南京210093
相关基金：国家自然科学基金（批准号：20875045）、国家自然科学基金委员会创新研究群体科学基金（批准号：20821063）和国家“九七三”计划项目（批准号：2010CB732401）资助.

关键词： CdTe量子点, 配体影响, 牛血清白蛋白, 选择性相互作用, 光致发光, CdTe quantum dots（QDs） , Ligand effect, Bovine serum albumin （BSA） , Selective interaction, Photoluminescence

中文摘要：

以巯基乙酸（TGA）、巯基丙酸（MPA）、巯基甘油（TG）、L-半胱氨酸（L—cys）和谷胱甘肽（GSH）等5种巯基分子为稳定剂，水相合成了5种cd代量子点．以牛血清白蛋白（BSA）作为靶分子，通过吸收光谱、荧光光谱和时间分辨荧光动力学等手段研究了各种配体分子稳定的CdTe量子点与BSA的直接相互作用．结果表明，5种量子点均能有效猝灭BSA的荧光，其猝灭程度按配体次序为GSH〉L—cys〉TGA〉TG〉MPA；而BSA对不同配体稳定的CdTe量子点的荧光光谱的影响则具有明显的选择性．BSA对TGA-CdTe和MPA-CdTe量子点的荧光先敏化增强而后猝灭下降；L-cys分子由于同时具有氨基和羧基而与BSA的相互作用较强，因此BSA能显著猝灭L—cys—CdTe量子点的荧光；而BSA对TG—CdTe量子点的荧光猝灭程度较小；GSH分子的空间效应使GSH—CdTe量子点的荧光被BSA猝灭的程度最小．吸收光谱和时间分辨荧光动力学研究表明，5种量子点与BSA之间的相互作用均为静态过程．探讨了量子点的配体分子结构与蛋白质的相互作用机理．

英文摘要：

Five water-soluble CdTe quantum dots （QDs） were synthesized using thioglycolic acid （TGA）, 3-mercaptopropionic acid （ MPA）, 1 -thioglycerol （ TG）, L-cysteine （L-cys） and glutathione （ GSH ） as stabili- zers, respectively. The interaction of CdTe QDs with bovine serum albumin （BSA） was studied by UV-Vis absorption and photoluminescence spectroscopy. Experimental results demonstrated that fluorescence of BSA could be markedly quenched by all these five CdTe QDs in Tris-HC1 buffer solution （pH = 7.40 ）. The quenching ability of CdTe QDs to BSA is as GSH〉L-cys〉TGA〉TG〉MPA in the order of ligands. However, when BSA was added into CdTe QDs solution, five CdTe QDs exhibited apparently selective responses to BSA. As the concentration of BSA increased, fluorescence intensity of CdTe QDs capped by TGA and MPA were both significantly enhanced firstly, then declined sharply. Under the same experimental conditions, fluore- scence intensity of L-cys-capped CdTe QDs was significantly quenched by BSA, and that of TG-capped CdTe QDs was only slightly quenched by BSA. While almost no change of GSH-capped QDs fluorescence was ob- served in the presence of BSA. These results indicated that ligand molecular structure of CdTe QDs played an important role in the interaction between BSA and CdTe QDs. Time-resolved luminescence dynamics suggested that the ground state complex of BSA and CdTe QDs could form by electrostatic interaction. Possible interaction mechanism of BSA with CdTe QDs was proposed based on the molecular structure of ligands.