Figure 2:

Schematic representation of pathways for peptide-mediated penetration of biological barriers to address key issues in non-viral gene carriers. Peptides can provide stealth properties to prevent opsonization while in circulation [20]. Furthermore, peptides can facilitate penetration of non-viral carriers across various cellular and sub-cellular barriers. Peptide-mediated transport mechanisms across the plasma membrane include uptake through endocytosis or macropinocytosis (right) [21]; active uptake through receptor-mediated endocytosis (bottom) [22]; and pore formation (left) [23]. Some peptides can mediate transcytosis through sequential endocytic uptake, subcellular transport, and exocytosis [24]. Within cells, peptides can facilitate endosomal escape [22] or nuclear targeting [25], leading to increased RNA delivery or gene transfection.