Srinivasan Charudharshini, Lee Jeunghoon, Papadimitrakopoulos Fotios, Silbart Lawrence K, Zhao Minhua, Burgess Diane J
Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Unit 3092, Storrs, 06269, USA.
Mol Ther. 2006 Aug;14(2):192-201. doi: 10.1016/j.ymthe.2006.03.010. Epub 2006 May 12.
Semiconductor nanocrystal quantum dots (QDs) allow long-term imaging in the cellular environment with high photostability. QD biolabeling techniques have previously been developed for tagging proteins and peptides as well as oligonucleotides. In this contribution, QD-decorated plasmid DNA was utilized for the first time for long-term intracellular and intranuclear tracking studies. Conjugation of plasmid DNA with phospholipid-coated QDs was accomplished using a peptide nucleic acid (PNA)-N-succinimidyl-3-(2-pyridylthio) propionate linker. Gel electrophoresis and confocal and atomic force microscopy (AFM) were used to confirm the structure of QD-DNA conjugates. AFM imaging also revealed that multiple QDs were attached in a cluster at the PNA-reactive site of the plasmid DNA. These QD-DNA conjugates were capable of expressing the reporter protein, enhanced green fluorescent protein, following transfection in Chinese hamster ovary (CHO-K1) cells with an efficiency of ca. 62%, which was comparable to the control (unconjugated) plasmid DNA.
半导体纳米晶体量子点（QD）能够在细胞环境中进行具有高光稳定性的长期成像。量子点生物标记技术此前已被开发用于标记蛋白质、肽以及寡核苷酸。在本研究中，首次将量子点修饰的质粒DNA用于长期的细胞内和细胞核内追踪研究。使用肽核酸（PNA）-N-琥珀酰亚胺基-3-（2-吡啶硫基）丙酸酯连接子实现了质粒DNA与磷脂包被的量子点的共轭。凝胶电泳、共聚焦显微镜和原子力显微镜（AFM）用于确认量子点-DNA共轭物的结构。原子力显微镜成像还显示，多个量子点以簇的形式附着在质粒DNA的PNA反应位点。在中国仓鼠卵巢（CHO-K1）细胞中转染后，这些量子点-DNA共轭物能够表达报告蛋白增强型绿色荧光蛋白，效率约为62%，这与对照（未共轭）质粒DNA相当。
