Figure 2.

Uptake of GNP by receptor-mediated endocytosis. (A,B) Schematic illustrating pathway of citrate-capped GNP uptake into the cell. (A) Describes the entry and sort mechanism for a single NP and multiple NPs, while (B) describes the entire flow of internalization and excretion. Once GNPs are attached to the receptors on the surface of the cell, membrane invagination occurs followed by budding into the cell, forming a vesicle. The internalized GNPs are sorted inside the vesicle and eventually fuse with lysosomes. GNPs are then excreted out of the cell. (C) Transmission electron microscope images of rat kidney cells treated with three different sizes of GNPs. Scale bar is 2 μm. Reproduced with permission [68,70]. Copyright American Chemical Society, 2009, 2011.