Dendrimer-Entrapped Gold Nanoparticles As A Nonviral Vector For Gene Delivery Application

Gene therapy is a technique using foreign therapeutic nucleic acid (such as plasmid, Minivector DNA or siRNA) as medicine by delivering them to certain cells or tissues to repair defective genes which are responsible for genetic disorders such as Parkinson's disease, cystic fibrosis, severe combined immunodeficiency, as well as cancer. The success of gene therapy is largely dependent on the development of an ideal delivery system that can selectively and efficiently deliver genetic materials to target cells without causing any associated pathogenic effects.As we all know, gene delivery systems include viral and nonviral systems. Viral systems exhibited high efficiency for both delivery and expression when delivering genes to different cell lines. However the safety problems raised by the toxicity, oncogenicity and immunogenicity of viral systems greatly hampered their routine use both in basic research laboratories and clinical settings. Hence, nonviral delivery systems, especially synthetic DNA delivery systems, have become an alternative method because they can be structurally varied, are relatively safe, and are able to carry large and diverse genetic material into cells.Nowadays/Development of high-efficiency non-viral gene delivery vectors still remains a great challenge.In this study, we report a new gene delivery vector based on dendrimer-entrapped gold nanoparticles (Au DENPs) with significantly higher gene transfection efficiency than that of dendrimers without Au NPs entrapped.The main research contents in this study include several parts as follows:first, Amine-terminated generation 5 poly(amidoamine) (PAMAM) dendrimers (G5.NH2) were utilized as templates to synthesize Au NPs with different dendrimer/Au atom molar ratios (1:25,1:50,1:75, and 1:100). Then, the formed Au DENPs were used to complex two different pDNAs encoding luciferase and enhanced green fluorescent protein for gene transfection studies. The Au DENPs/pDNA polyplexes with different N/P ratios and composition of Au DENPs were fully characterized by gel retardation assay, cytotoxicity testing, followed by transfection into 3 different cell lines. We show that the Au DENPs can effectively compact the pDNA, allowing for highly efficient gene transfection into cells. The transfection efficiency of Au DENPs was more than 100 times higher than G5.NH2 without Au NPs entrapped at the N/P ratio of 2.5. It is expected that Au DENPs may be used as a highly efficient gene delivery vector to transfect different genes for various biomedical applications.