Figure 2.

Peptide-mediated targeting via ligand/cell-surface interactions. These strategies use ligands grafted onto the carrier/drug surface to increase the intracellular uptake of drug in target tissues (Table 2). A ligand is presented by the carrier, which binds to a moiety on the cellular surface, like specific receptors or nonspecific proteoglycans [141]. Surface binding may be followed by internalization through receptor-mediated endocytosis or other uptake mechanisms. Once internalized, the carrier or drug may be further processed via other cellular factors, such as pH or enzymatic activity.