作为一种新型的荧光探针, 量子点(QD)已经受到越来越多的重视, 制备工艺也显得格外重要。水相中合成的量子点效率低, 油相中的量子点经过转相以后效率也大大衰减。本论文利用再沉淀包覆的方法制备了具有良好的水溶性的掺杂绿光CdSe@ZnS的纳米颗粒G-NPs(534 nm)和掺杂红光CdSe@ZnS的纳米颗粒R-NPs(610 nm), 具有窄的半峰宽(G-NPs ~29 nm, R-NPs ~31 nm), 较小的粒径(45 nm), 并在此基础上通过发射光谱与荧光衰减研究了量子点之间的能量传递现象。该方法保留了量子点原来的性质, 基于其优良的光学性质, 对人类肝细胞肝癌细胞株(HepG2)进行了荧光标记, 从共聚焦成像实验结果看出, 纳米颗粒得到了良好的吞噬效果。

As a new kind of fluorescent probe, quantum dots(QD) have got more and more attention especially the preparation. However, QDs synthesized in aqueous phase suffer from the low efficiency and quantum yield of oil-soluble QDs dropped significantly after the ligand exchange. In this work, we report a type of green CdSe@ZnS-based(G-NPs, 534 nm) and red CdSe@ZnS-based (R-NPs, 610 nm) nanoparticles prepared via a facile reprecipitation-encapsulation method. They possess a narrow half peak width(G-NPs~29 nm, R-NPs~31 nm), smaller particle size(45 nm). Also, we discuss critical energy transfer mechanism through the emission spectrum and the fluorescence decay. This method preserves the properties of QDs, and we used the NPs to label cancer cells(HepG2) due to their excellent optical properties. Fluorescence images of the cells clearly indicate that a good fraction of the NPs has been swallowed.