Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China.
ACS Nano. 2010 Nov 23;4(11):6483-90. doi: 10.1021/nn101445y. Epub 2010 Oct 26.
The endocytic pathway of a recombinant protein toxin, ricin A-chain (RTA), delivered by multiwalled carbon nanotubes (MWCNTs) was tracked in HeLa cells by tagging RTA with enhanced green fluorescent protein (EGFP). EGFP-RTA was found to accumulate in the endosome and to be retrogradely transported to the endoplasmic reticulum, from which it translocated into the cytosol. Nuclear staining, Z-axis scanning with a laser scanning confocal microscope (LSCM), and transmission electron microscopy (TEM) indicated that the RTA exerted its toxic effects. Endocytosis-inhibiting tests with LSCM and flow cytometry showed that MWCNT-EGFP-RTA conjugates penetrated cells principally via clathrin-mediated endocytosis. These studies are beneficial to understanding the MWCNT-based intracellular drug delivery mechanism and provide guidelines for designing promising MWCNT-based vectors for targeting diagnostic or therapeutic compounds, not only to specific cells, but even to specific cellular compartments.
通过将增强型绿色荧光蛋白（EGFP）标记到重组蛋白毒素蓖麻毒素 A 链（RTA）上，追踪了多壁碳纳米管（MWCNTs）递送的 RTA 的内吞途径。在 HeLa 细胞中发现 EGFP-RTA 在内体中积累，并被逆行运输到内质网，从内质网中它易位到细胞质中。核染色、激光扫描共聚焦显微镜（LSCM）的 Z 轴扫描和透射电子显微镜（TEM）表明 RTA 发挥了其毒性作用。LSCM 和流式细胞术的内吞抑制试验表明，MWCNT-EGFP-RTA 缀合物主要通过网格蛋白介导的内吞作用穿透细胞。这些研究有助于理解基于 MWCNT 的细胞内药物递送机制，并为设计有前途的基于 MWCNT 的载体提供指导，不仅可以靶向特定细胞，甚至可以靶向特定的细胞区室，用于靶向诊断或治疗化合物。
