Department of Biomedical Engineering, College of Engineering and Applied Sciences, Nanjing University, China.
Biomater Sci. 2018 Nov 1;6(11):3085-3095. doi: 10.1039/c8bm00928g. Epub 2018 Oct 10.
Targeted delivery of nanomaterials to specific intracellular locations is essential for the development of many nanomaterials-based biological applications. Thus far the targeting performance has been limited due to various intracellular transport barriers, especially intracellular vesicle trapping. Here we report the application of permeation enhancers based on organic solvents in small percentage to enhance the intracellular targeted delivery of nanomaterials. Previously permeation enhancers based on organic solvents and ionic liquids have been used in overcoming biological transport barriers at tissue, organ, and cellular levels, but this strategy has so far rarely been examined for its potential in facilitating transport of nanometer-scale entities across intracellular barriers, particularly intracellular vesicle trapping. Using the cell nucleus as a model intracellular target and Tat peptide-conjugated quantum dots (QDs-Tat) as a model nanomaterial-based probe, we demonstrate that a small percentage (e.g. 1%) of organic solvent greatly enhances nucleus targeting specificity as well as increasing endocytosis-based cellular uptake of QDs. We combine vesicle colocalization (DiO dye staining), vesicle integrity (calcein dye release), and single-particle studies (pair-correlation function microscopy) to investigate the process of organic solvent-enhanced vesicle escape of QDs-Tat. The organic solvent based vesicle escape-enhancing approach is found to be not only very effective but minimally invasive, resulting in high vesicle escape efficiency with no significant disruption to the membrane integrity of either intracellular vesicles or cells. This approach drastically outperforms the commonly used vesicle escape-enhancing agent (i.e., chloroquine, whose enhancement effect is based on disrupting vesicle integrity) in both potency and minimal invasiveness. Finally, we apply organic solvent-based targeting enhancement to improve the intracellular delivery of the anticancer drug doxorubicin (DOX).
靶向递送至特定细胞内位置对于许多基于纳米材料的生物应用的发展至关重要。迄今为止，由于各种细胞内转运障碍，特别是细胞内囊泡捕获，靶向性能受到限制。在这里，我们报告了基于有机溶剂的渗透增强剂在小比例下应用于增强纳米材料的细胞内靶向递送至特定位置。以前，基于有机溶剂和离子液体的渗透增强剂已被用于克服组织、器官和细胞水平的生物转运障碍，但迄今为止，很少有研究考察其在促进纳米级实体穿过细胞内障碍（特别是细胞内囊泡捕获）的运输方面的潜力。我们使用细胞核作为模型细胞内靶标和 Tat 肽缀合的量子点（QDs-Tat）作为模型纳米材料探针，证明了小比例（例如 1%）的有机溶剂极大地增强了核靶向特异性以及增加了基于内吞作用的细胞摄取量子点。我们结合囊泡共定位（DiO 染料染色）、囊泡完整性（钙黄绿素染料释放）和单粒子研究（对相关函数显微镜）来研究有机溶剂增强的 QDs-Tat 囊泡逃逸过程。发现基于有机溶剂的囊泡逃逸增强方法不仅非常有效，而且微创，导致囊泡逃逸效率高，而对细胞内囊泡或细胞的膜完整性没有明显破坏。与通常使用的囊泡逃逸增强剂（即基于破坏囊泡完整性的氯喹）相比，这种方法在效力和微创性方面都有很大的优势。最后，我们应用基于有机溶剂的靶向增强来提高抗癌药物阿霉素（DOX）的细胞内递送。
