Kang Bin, Yu De-Cai, Chang Shu-Quan, Chen Da, Dai Yao-Dong, Ding Yitao
College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China.
Nanotechnology. 2008 Sep 17;19(37):375103. doi: 10.1088/0957-4484/19/37/375103. Epub 2008 Aug 1.
Herein we studied the uptake, trafficking and distribution of folate conjugated single walled carbon nanotubes (SWNTs) within living cells. SWNTs were noncovalently functionalized with chitosan and then linked with folate acid and fluorescence dye Alexa Fluor 488 (denoted FA-SWNTs). Hep G2 cells were cultured in vitro and incubated with FA-SWNTs at different levels. The FA-SWNTs exhibited a concentration-dependent uptake within Hep G2 cells, and Hep G2 cells were able to internalize FA-SWNTs via a folate receptor-mediated pathway. The distribution of nanotubes inside cells demonstrated that the FA-SWNTs only locate in the cytoplasm and not in nuclei, indicating the failure of transporting through the nuclear envelope. Transmission electron microscope (TEM) results showed the presence of FA-SWNTs in lysosomes and the discharge to extracellular space after incubation with nanotubes for 5 h. No obvious cellular death rate was observed when the concentration of nanotubes was below 50 µg ml(-1). However, cells with FA-SWNT uptake showed a concentration-dependent apoptosis. These discoveries might be helpful for understanding the interaction of SWNTs and living cells.
在此，我们研究了叶酸共轭单壁碳纳米管（SWNTs）在活细胞内的摄取、运输和分布情况。SWNTs通过壳聚糖进行非共价功能化，然后与叶酸和荧光染料Alexa Fluor 488相连（记为FA-SWNTs）。体外培养Hep G2细胞，并与不同浓度的FA-SWNTs孵育。FA-SWNTs在Hep G2细胞内呈现浓度依赖性摄取，且Hep G2细胞能够通过叶酸受体介导的途径内化FA-SWNTs。细胞内纳米管的分布表明，FA-SWNTs仅位于细胞质中，而非细胞核中，这表明其无法穿过核膜进行运输。透射电子显微镜（TEM）结果显示，孵育纳米管5小时后，溶酶体中存在FA-SWNTs并向细胞外空间释放。当纳米管浓度低于50 μg ml(-1)时，未观察到明显的细胞死亡率。然而，摄取了FA-SWNTs的细胞呈现浓度依赖性凋亡。这些发现可能有助于理解SWNTs与活细胞之间的相互作用。
