[Table/Fig-3]:

Strategies to improve gene transfer efficacy of non viral vectors

Barriers	Functional components	Strategies -rationale	Molecules studied
Extracellular stability	Carrier molecules	DNA condensation- protects from nucleases	Protamine, lipids, gelation
	Hydrophobic moiety	Steric stability achieved by surface charge shielding	PEG ylation
Internalization	Targeting ligands	Receptor mediated endocytosis	Transferrin, EGF, antibodies, RGD
Intracellular trafficking	Endosomal disruptive agent	Escape from endosomes and unpacking by proton sponge effect	PEI, DOPE
Nuclear entry	Nuclear localization signal	Nuclear entry	Tat, ReV.