Wei Yifeng, Jana Nikhil R, Tan Shawn J, Ying Jackie Y
Institute of Bioengineering and Nanotechnology, The Nanos, Singapore 138669.
Bioconjug Chem. 2009 Sep;20(9):1752-8. doi: 10.1021/bc8003777.
TAT peptide functionalized shell-core ZnS-CdSe quantum dots (QDs) have been prepared by three different methods, direct ligand exchange with cysteine-terminated TAT (TAT-QD(lig exch)), and covalent conjugation to QDs coated with silanes (TAT-QD(silica)) and polyacrylate derivatives (TAT-QD(polyacrylate)). The silica and polyacrylate coatings incorporated multiple primary and secondary amines, introducing positive surface charges onto the QDs, providing high water solubility and sites for peptide conjugation, while inducing the "proton sponge effect". The different coating methods produced particles of different sizes, surface charges, and colloidal stability; these factors jointly influenced the cellular uptake and subcellular localization of these particles. As the particle size increased, (TAT-QD(lig exch) (6 nm) < TAT-QD(silica) (10 nm) < QD(polyacrylate) (25 nm)), both the particle surface charge and cellular uptake increased. The smaller TAT-QD(lig exch) and TAT-QD(silica) particles were localized mainly in the perinuclear regions, while the larger TAT-QD(polyacrylate) particles were localized in both the perinuclear regions and the lysosomes. Compared to the other TAT-QDs, TAT-QD(lig-exch) has a lower colloidal stability and was more cytotoxic due to the weak binding of the ligands.
已通过三种不同方法制备了TAT肽功能化的核壳型硫化锌-硒化镉量子点（QDs），即与半胱氨酸末端的TAT进行直接配体交换（TAT-QD(配体交换)），以及与涂有硅烷的量子点（TAT-QD(二氧化硅)）和聚丙烯酸酯衍生物（TAT-QD(聚丙烯酸酯)）进行共价偶联。二氧化硅和聚丙烯酸酯涂层含有多个伯胺和仲胺，在量子点上引入正表面电荷，提供高水溶性和肽偶联位点，同时引发“质子海绵效应”。不同的涂层方法产生了不同尺寸、表面电荷和胶体稳定性的颗粒；这些因素共同影响了这些颗粒的细胞摄取和亚细胞定位。随着粒径增大（TAT-QD(配体交换)（6纳米）<TAT-QD(二氧化硅)（10纳米）<TAT-QD(聚丙烯酸酯)（25纳米）），颗粒表面电荷和细胞摄取均增加。较小的TAT-QD(配体交换)和TAT-QD(二氧化硅)颗粒主要定位于核周区域，而较大的TAT-QD(聚丙烯酸酯)颗粒定位于核周区域和溶酶体中。与其他TAT-QDs相比，TAT-QD(配体交换)具有较低的胶体稳定性，并且由于配体的弱结合而具有更高的细胞毒性。
