Figure 3

A) Lipoplex-mediated transfection: 1) Cationic lipids forming micellar structures called liposomes are complexed with DNA to create lipoplexes2) The complexes are internalized by endocytosis, resulting in the formation of a double-layer inverted micellar vesicle. 3) During the maturation of the endosome into a lysosome, the endosomal wall might rupture, releasing the contained DNA into the cytoplasm and potentially towards the nucleus. 4) DNA imported into the nucleus might result in gene expression. Alternatively, DNA might be degraded within the lysosome. B) peptide-based nucleic acid delivery systems: Both covalent attachment and/or non-covalent complexes of peptide-DNA are acting similar to lipid-based systems. The designed cationic peptides must be able to 1) tightly condense DNA into small, compact particles; 2) target the condensate to specific cell surface receptors; 3) induce endosomal escape; and 4) target the DNA cargo to the nucleus for reporter gene expression.