Liu Betty R, Li Jheng-Fong, Lu Shu-Wan, Leel Han-Jung, Huang Yue-Wern, Shannon Katie B, Aronstam Robert S
Department of Natural Resources and Environmental Studies, and Institute of Biotechnology, National Dong Hwa University, Hualien 97401, Taiwan.
J Nanosci Nanotechnol. 2010 Oct;10(10):6534-43. doi: 10.1166/jnn.2010.2637.
Protein transduction domains comprised of basic amino acid-rich peptides, can efficiently deliver covalently fused macromolecules into cells. Quantum dots (QDs) are luminescent semiconductor nanocrystals that are finding increasing application in biological imaging. Previous studies showed that protein transduction domains mediate the internalization of covalently attached QDs. In this study, we demonstrate that arginine-rich intracellular delivery peptides (cell-penetrating peptides; CPPs), analogs of naturally-occuring protein transduction domains, deliver noncovalently associated QDs into living cells; CPPs dramatically increase the rate and efficiency of cellular uptake of QD probes. The optimal molecular ratio between arginine-rich CPPs and QD cargoes for cellular internalization is approximately 60:1. Upon entry into cells, the QDs are concentrated in the perinuclear region. There is no cytotoxicity following transport of QDs present at concentrations up to 200 nM. The mechanism for arginine-rich CPP/QD complexes to traverse cell membrane appears to involve a combination of internalization pathways. These results provide insight into the mechanism of arginine-rich CPP delivery of noncovalently attached cargoes, and may provide a powerful tool for imaging in vivo.
由富含碱性氨基酸的肽组成的蛋白质转导结构域能够有效地将共价融合的大分子递送至细胞内。量子点（QDs）是发光半导体纳米晶体，在生物成像中的应用越来越广泛。先前的研究表明，蛋白质转导结构域介导共价连接的量子点的内化。在本研究中，我们证明富含精氨酸的细胞内递送肽（细胞穿透肽；CPPs），即天然存在的蛋白质转导结构域的类似物，能够将非共价结合的量子点递送至活细胞中；CPPs显著提高了量子点探针的细胞摄取速率和效率。细胞内化时，富含精氨酸的CPPs与量子点货物的最佳分子比例约为６０：１。进入细胞后，量子点集中在核周区域。浓度高达200 nM的量子点运输后没有细胞毒性。富含精氨酸的CPP/量子点复合物穿过细胞膜的机制似乎涉及内化途径的组合。这些结果为富含精氨酸的CPP递送非共价连接货物的机制提供了见解，并可能为体内成像提供有力工具。
