L-Cys/MPA共修饰CdTe量子点:制备、表征及其在细胞标记中的应用

以L-半胱氨酸(L-Cys)和巯基丙酸(MPA)为共修饰剂在水相中快速合成高质量CdTe量子点.通过紫外-可见分光光谱、荧光光谱、荧光寿命衰减曲线、透射电子显微图片、XRD图谱等相关方法对产物进行表征.调节L-Cys和MPA的摩尔比,对CdTe量子点的生长速率和光学特性有明显影响.结果证实:与单一修饰剂L-Cys或MPA相比,L-Cys/MPA共修饰CdTe量子点具有较快的荧光发射峰红移速率,且其粒径分布均一、稳定性强.50L-CdTe(L-Cys与MPA摩尔比为50%)的荧光量子产率达到66.4%,75L-CdTe(L-Cys与MPA摩尔比为75%)的荧光寿命为46.8 ns.细胞毒性实验证明75L-CdTe量子点对SiHa细胞毒性较小,细胞存活率为75%~95%.进一步将其用于标记细胞,表明75L-CdTe量子点能有效地对SiHa细胞进行荧光标记.L-Cys/MPA共修饰CdTe量子点具有良好的荧光特性和生物相容性,在生物医药领域具有重要的应用价值.

CdTe Quantum Dots Using L-Cys/MPA as Mixed-ligands: Preparation,Characterization and Application in Cell Labeling

High-quality CdTe quantum dots (QDs) were rapidly synthesized in aqueous phase using both L-Cysteine (L-Cys) and mercaptopropionic acid (MPA) as mixed-ligands. Different technologies including UV-Vis spectra, fluorescence spectra, luminescence decay curves, transmission electron microscopy and X-ray diffraction analysis were employed to characterize the prepared QDs. The ratio of L-Cys and MPA was found to have influence on the growth kinetics and optical properties of the obtained QDs. Compared to single ligand of L-Cys or MPA, L-Cys/MPA as mixed-ligands could accelerate the red shifted rate of fluorescence emission peak wavelength effectively. CdTe QDs capped with mixed-ligands exhibited a high uniformity in diameter and an excellent photostability. 50L-CdTe (L-Cys/MPA molar ratio was 50%) held a high quantum yield of 66.4% and 75L-CdTe (L-Cys/MPA molar ratio was 75%) exhibited a luminescence decay lifetime of 46.8 ns. MTT assays showed that 75L-CdTe with emission of 615 nm maintained 75%-95% SiHa cell viability. Further study of labeling SiHa cell with the as-prepared 75L-CdTe indicated that the QDs are excellent biomarkers for SiHa cell. L-Cys and MPA as mixed-ligands with proper design can be employed to fabricate CdTe QDs with superior fluorescence properties and biocompatibility, which have potential in biological and medical fields as biomarker-candidates.