CdSe-ZnS QDs/PLGA纳米复合材料的性能及体外降解行为

Optical Properties and in Vitro Degradation of Cd Se-ZnS Quantum Dots/Poly( lactic-co-glycolic acid) Nanocomposites

采用溶液浇铸法制备了不同CdSe-ZnS量子点(Quantum dots QDs)含量的QDs/乳酸-乙醇酸共聚物(PLGA)复合材料薄膜,通过傅里叶变换红外光谱仪、透射电子显微镜(TEM)、光致发光光谱仪(PL)及紫外-可见吸收光谱仪(UV-Vis)等对薄膜的微观结构与光学性能进行了表征,并对不同降解时间后降解液的pH值、薄膜的发光情况和相对分子质量及其分布进行了测试。PL及UV-Vis结果显示,QDs/PLGA纳米复合材料的发光性能良好,吸光度随QDs含量增加而增大;TEM结果显示,QDs在基体中分散良好;在体外降解过程中,凝胶渗透色谱和缓冲液p H值测试结果说明,量子点催化了PLGA的降解;复合材料的荧光效应随着降解时间的延长逐渐减弱。以上结果说明,采用简单的溶液浇铸法制备的CdSe-ZnS QDs/PLGA复合材料发光性能稳定优异,且可以通过检测荧光效应变化以实现动态监测QDs/PLGA复合材料的降解进程。

CdSe-ZnS quantum dots （QDs）/poly （ lactic-co-glycolic acid） （ PLGA ） （ 75/25 ） nanocomposites films, containing different concentrations of CdSe-ZnS QDs, were prepared via solution casting. The optical properties and in vitro degradation of the QDs/PLGA nanocomposites were investigated. The photoluminescence （PL） spectra and ultraviolet-visible （UV-Vis） absorption spectra evidence excellent optical properties of the QDs upon their compositing with PLGA, in which the UV-Vis and PL intensities improve with increase of the concentration of QDs. The TEM images reveal that the QDs are uniformly dispersed in the PLGA matrix. Both the gel permeation chromatography results and the variations in the pH values of buffer solutions containing PLGA and QDs/PLGA nanocomposites films, respectively, confirm that the existence and uniform dispersion of QDs, to some extent, lead to a faster degradation rate of the QDs/PLGA compared with the unfilled PLGA. The PL intensity of QDs/PLGA nanocomposites films decreases all along with progress of the degradation process. All the results show that the QDs/ PLGA nanocomposites films can he prepared via solution casting method, and have a huge potential value for monitoring in vivo degradation of QDs/PLGA through detection of the changes in fluorescence intensities.