Gene Delivery And Immunological Safety Of Pegylated Dendrimer-entrapped Gold Nanoparticles Modified With Folic Acid

Gene therapy has become one of the research focus on the cure cancer mainly for the prevention and treatment of malignant tumors with good accuracy and specificity.Gene therapy has less side effects and higher security compared with other treatments.The efficiency of gene therapy is mainly ascribed to the excellent transformation ability of the gene carrier.The gene vectors transmit the exogenous gene to the target cells and then release the genes in the cells to realize gene therapy.The non-viral vector has attracted extensive investigations because it is high security,low immunogenicity,unrestricted DNA size in transformation,and thus more potential than the viral one in gene delivery.Dendrimer has high branched spherical shape,internal space,monodispersity,good stability and solubility.It is an ideal vector for gene transfection.It modified with polyethylene glycol monomethyl ether(m PEG)can reduce cytotoxicity,immunogenicity and improve gene transfection efficiency.Besides,it modified with folic acid(FA)can achieve tumor targeting ability.In this research,we report on a type of new non-viral gene delivery vectors which are partially modified with m PEG(Au DENPs-m PEG)(P1)and folic acid(FA)PEGylated dendrimerentrapped gold nanoparticles(Au DENPs-PEG-FA)(P2),respectively,based on generation 5(G5)poly dendrimer-entrapped gold nanoparticles(Au DENPs).The p DNA encoded enhanced green fluorescent protein(EGFP)were successfully compacted by the partially PEGylated Au DENPs and effectively delivered into He La cells.The two vectors were characterized by 1H NMR,TEM and UV-Vis spectrometry.The optimum N/P of vectors compacting plasmid DNA(p DNA)is determined by electrophoretic mobility shift assay According to the measured DLS and zeta potential,we estimated whether the two vectors with p DNA complex were beneficial to enter He La cells.Our hypothesis is that Au DENPs can effectively compact the p DNA,allowing for highly efficient gene transfection into the selected cell lines as demonstrated by the EGFP expression and RLU expression experiments.The efficiency of p DNA delivered to He La cells was examined by flow cytometry and the confocal microscopy.Based on our investigations,we can conclude that the efficiency of gene delivery of P2 is much higher than P1 at N/P of 1:1,2.5:1 and 5:1,respectively.The particle size and the zeta potential of the complexes were suitable for cell endocytosis,and the cell viability was still above 75% when the concentration of the material was extremely high.The vector containing FA and N/P is 0.5 can not only efficiently compact the plasmid DNA and completely compact it,but can greatly enhance the transfection efficiency and improve cell compatibility in some degree.At N/P = 2.5,the transfection efficiency was much higher than Au DENPs without folic acid modification.Furthermore,Au DENPs-PEG-FA will not trigger innate immune system according to the quantification of inflammatory cytokines by q RT-PCR.However,when the macrophage incubated with polyplexes formed by the vectors and Cp G DNA,which is known as high immunogenicity,the immune response cannot be mitigated by vectors.With high gene transfection efficiency,low cytotoxicity and immunogenicity,PEGylated Au DENPs modified by folic acid may be a superior alternative for gene delivery in biomedical application.