Figure 4.

Some common routes by which functionalized QDs internalize into the target cells. (A) Clathrin-mediated endocytosis. Following concentration of QDs at the receptor region, QDs are engulfed into clathrin-coated cell membrane invaginations, forming clathrin-coated vesicles. Dynamin mediates the dissociation of the aforementioned vesicles from the cell membrane into the cytosol leading to the formation of endosome. Subsequently, QDs should escape from the endosome and be released into the cytosol to avoid lysosomal degradation. (B) Caveolae-mediated endocytosis. The bindings of functionalized QDs to certain receptors mediates their internalization into the target cells via cholesterol-rich flask-shaped membrane invaginations, called caveolae, which subsequently dissociate from the cell membrane, forming caveosomes. Caveosomes are thought to be less destructive than endosomes. (C) Macropinocytosis. The binding of functionalized QDs to certain receptors activates the formation of cell membrane ruffles that engulf QDs into the cytosol forming macropinosomes, which subsequently leak their cargo into the cytosol. Created by BioRender.com.