巯基丙酸修饰CdTe量子点光学性能及其生物相容性研究

目的:研究水相合成巯基丙酸(MPA)修饰的CdTe量子点(CdTe QDs)用于对细胞的标记,探讨其与活细胞的生物相容性.方法:水相中合成MPA CdTe QDs;透射电子显微镜、荧光分光光度计及紫外分光光度计表征MPA CdTe QDs;将MPA CdTe QDs与亲和素连接、纯化、制备成MPA CdTeQDs荧光探针;应用激光扫描共聚焦显微术观察MPA CdTeQDs荧光探针标记小鼠腹腔巨噬细胞(PM@)MHC Ⅱ抗原的表达;以黑色素瘤B-16细胞为靶细胞,应用细胞培养和MTT法观察MPA CdTe QDs的生物相容性.结果:水相中合成MPACdTe量子点粒径均匀,具备良好的光学性能,稳定性强;以量子点标记亲和素(QDs-Avidin)作为荧光探针标记小鼠腹腔巨噬细胞MHCⅡ抗原,在荧光显微镜和激光共聚焦显微镜下可见标记细胞具有较强的荧光表达;MPA CdTe QDs在高浓度时有一定的细胞毒性,但是,在用于对细胞进行荧光标记成像的浓度范围内,量子点对细胞活性的影响很小.结论:MPA CdTe QDs大小比较均匀且具有较好的光学性能,不易漂白淬灭,稳定性好,是一种新的良好的荧光标记物;MPACdTe QDs具有较好的生物相容性.

The photological function of MPA coated CdTe QDs and their biocompatibility

AIM: To investigate the CdTe quantum dots coated with MPA and explore its biocompatibility with living cells. METHODS: CdTe quantum dots coated with MPA were prepared in aqueous phase and MPA CdTe QDs were Characterized with TEM, fluorospectrophotometer and ultraviolet spectrophotometer. QDs were Modified with with avidin, purified and prepared as flurescent probe. LSCM was used to observe the expression of MHC Ⅱ antigen on PMφ cells, which was labeled by QDs. Cell culture and MTT assays were used to determine the biocompatibility of MPA coated CdTe quantum dots with the B-16 cells as target cells. RESULTS: The particle diameter of CdTe quantum dots prepared in aqueous phase was well distributed. They had good photological performance and greater stability after coated with MPA. MHC Ⅱ antigen on PMφ was labeled with the QDs-Avidin fluorescent probe showed great fluorescence intensity, which was easy to be detected by fluorescence microscope and LSCM. MPA CdTe QDs showed cytotoxicity when its density was very high, but they showed little cytotoxicity during the normal use of influence label density limit. CONCLUSION: MPA CdTe QDs can be used as new fluorescent lable as they are of even size, not easy to bleach or quench, have good photological performance and stability and good biocompatibility.