中文摘要：

通过降低反应物中三．半胱氨酸（L-Cys）的比例，在水相快速合成了近红外CdTe量子点，使之对巯基化合物产生荧光响应．并以此构建了一种基于表面配体缺失的CdTe近红外荧光量子点的巯基探针，为生物样品中的硫醇检测提供简便经济、高灵敏度和高选择性的新方法．在其它多种氨基酸和生物液体中主要离子、分子共存的情况下，我们所制备的近红外量子点对L—Cys、同型半胱氨酸（Hcy）和谷胱甘肽（GSH）的荧光检测中显示了良好的选择性和灵敏度．在血清和细胞提取液中，加标5．0gmol·L-1硫醇的回收率均在90％～109％范围内．该方法对L—Cys，Hcy和GSH的检出限（3s）分别为43，46和63nmol·L-1．

英文摘要：

As well known that conventional aqueous synthesis of the near-infrared （NIR） CdTe quantum dots （QDs） using thiol ligands as capping reagents is usually very time-consuming. To overcome this defect and prepare NIR CdTe QDs, we present a fast and facile route in aqoueous phase under atmospheric pressure using L-cysteine （L-Cys） as capping reagents. The influences of various experimental conditions on the growth rate and luminescent properties of the obtained CdTe QDs have been systematically investigated, including Te-to-Cd ratio, L-Cys-to-Cd ratio and pH value. The experiment results suggested that lower ratio of Te ： Cd or L-Cys ： Cd and high pH value would markedly shortened the reaction time. Fur- thermore, the obtained QDs were used as a kind of NIR fluorescent probes for thiol detection in biological fluids. The change in the fluorescence intensity of the NIR CdTe QDs in the presence of 5.0 μmoloL-1 homocysteine （Hey）, L-Cys or glutathione （GSH） with different interaction time was measured. The effect of pH on the enhanced fluorescence intensity of the NIR CdTe QDs （10 mgoL-1） at 5.0 μmoloL-I Hcy, L-Cys or GSH and the fluorescence responses ofNIR CdTe QDs to 20 essential amino acids （5.0μmol,L-1 for L-Cys, 5.0 mmol·L-1 for the other 19 amino acids） in pH 7.0 PBS buffer was investigated. The probe offered good sensitivity and selectivity for detecting L-Cys, Hcy and GSH in the presence of 20 other amino acids, main relevant metal ions, and some other molecules in biological fluids. The recovery of spiked 5.0 μmoloL-t thiols in human serum and cell extracts ranged from 90% to 109%. The precision for 11 replicate measurements of the thiols at 5.0 Bmol·L-1 is in the range of 2.4%~3.3%. The detection limits （3s） for L-Cys, Hcy and GSH are 43, 46 and 63 nmol.L-1, respectively. For real sample measurement, four serum samples and cell extract sample from two cancer cell lines （Hela and HepG2） were chosen and the analytical results were comparable with HPLC assay.