CdTe量子点对胰凝乳蛋白酶的荧光标记

The Fluorescence Labeling of Chymotrypsin by CdTe Quantum Dots

用巯基丙酸作为表面修饰剂在水相中制备了稳定的CdTe纳米量子点。利用量子点外层包被的巯基丙酸上的羧基,实现了量子点与胰凝乳蛋白酶的直接偶联。偶联后溶液的吸光度值略有增大而吸收峰位不变,同时荧光强度明显增强,荧光发射峰位稍有蓝移。通过荧光发射光谱确定了CdTe量子点与胰凝乳蛋白酶偶联的最佳反应条件为:pH9.0,反应温度37℃,反应时间1.5 h。重点考察了NaCl浓度和胰凝乳蛋白酶浓度对量子点与胰凝乳蛋白酶偶联产物荧光强度的影响。

Stabilized CdTe quantum dots were prepared in aqueous solution by using mercaptopropionic acid（MPA） as the surface modifier. With the carboxyl groups of MPA on the surface of CdTe QDs, direct conjugation of QDs with chymotrypsin was realized. A slight increase Of the solution absorbance but retaining the position of the absorption peak was observed and the fluorescence intensity was significantly enhanced with a 2 nm blue shift of the fluorescent emission peak. The optimum pH, reaction temperature and time for conjugating the CdTe quantum dots with chymotrypsin were 9.0, 37 ℃ and 1.5 h, respectively. The effects of NaCl and chymotrypsin concentration on fluorescence intensity of QDs-chymotrypsin solution were discussed.