Pal Suman, Jana Nikhil R
School of Materials Science, Indian Association for the Cultivation of Science, Kolkata-700032, India.
J Phys Chem B. 2020 Dec 31;124(52):11827-11834. doi: 10.1021/acs.jpcb.0c08992. Epub 2020 Dec 18.
Direct membrane translocation of quantum dot for straight access to cytosol is essential for subcellular targeting and intracellular imaging application. However, cellular entry of the quantum dot usually occurs via endocytosis that is associated with vesicular entrapment followed by trafficking to endosome/lysosome. Thus, quantum dots are not freely available in cytosol that restrict their subcellular targeting/labeling. Recent works show that arginine-terminated nanoparticle of <10 nm size (Au-arginine) can enter into cell via direct membrane translocation and delivers protein into subcellular compartments. Here we report Au-arginine as delivery carrier for direct membrane translocation of quantum dot with the straight access to cytosol. The approach involves simple mixing of the colloidal solutions of quantum dot and Au-arginine followed by incubation with cell. We found that quantum dot forms colloidal assembly after binding with Au-arginine, enter into cell with higher efficiency and faster kinetics, distribute homogeneously in cytosol. It has also been observed that the cell uptake mechanism of quantum dot shifts from energy dependent endocytosis to energy independent nonendocytic processes after the binding with Au-arginine. This approach is independent of cell type and can be adapted for direct cytosolic delivery of wide variety of nanoparticles.
量子点直接跨膜转运以直接进入胞质溶胶对于亚细胞靶向和细胞内成像应用至关重要。然而，量子点进入细胞通常通过内吞作用，这与囊泡截留相关，随后转运至内体/溶酶体。因此，量子点在胞质溶胶中并非可自由利用，这限制了它们的亚细胞靶向/标记。最近的研究表明，尺寸小于10 nm的精氨酸末端纳米颗粒（金-精氨酸）可通过直接跨膜转运进入细胞，并将蛋白质递送至亚细胞区室。在此，我们报道金-精氨酸作为量子点直接跨膜转运的递送载体，可直接进入胞质溶胶。该方法包括将量子点和金-精氨酸的胶体溶液简单混合，然后与细胞孵育。我们发现量子点与金-精氨酸结合后形成胶体聚集体，以更高的效率和更快的动力学进入细胞，在胞质溶胶中均匀分布。还观察到，量子点与金-精氨酸结合后，其细胞摄取机制从能量依赖性内吞作用转变为能量非依赖性非内吞过程。该方法与细胞类型无关，可适用于多种纳米颗粒的直接胞质递送。
