Self-assembled nanoparticles based on modified cationic dipeptides and DNA: novel systems for gene delivery.

Gene therapy is most effective when delivery is both efficient and safe. However, it has often proven difficult to find a balance between efficiency and safety in case of viral or polymeric vectors for gene therapy. Peptide based delivery systems may be attractive alternatives but their relative instability to proteolysis is a major concern in realizing their potential application in biomedical sciences. In this work we report gene delivery potential of nanoparticles (Nps) synthesized from cationic dipeptides containing a non-protein amino acid α, β-dehydrophenylalanine (∆Phe) residue. Dipeptides were synthesized using solution phase peptide synthesis method. Nps were formed using self-assembly. Nps were characterized using light scattering, electron microscopy. Transfection efficiency was tested in hepatocellular carcinoma (HuH 7) cells. The cationic dipeptides condensed plasmid DNA into discrete vesicular nanostructures. Dipeptide Nps are non-cytotoxic, protected the condensed DNAs from enzymatic degradation and ferried them successfully inside different types of cells. GFP encoding plasmid DNA loaded dipeptide Nps showed positive transfection and gene expression in HuH 7 cells. The cationic dipeptide Nps can successfully deliver DNA without exerting any cytotoxic effect. Owing to their simple dipeptide origin, ease of synthesis, enhanced enzymatic stability as well unmatched biocompatibility, these could be successfully developed as vehicles for effective gene therapy.