| DNA delivery has become a powerful popular research tool for elucidating gene structure, regulation, and function, as well as treating and controlling diseases, such as gene therapy and DNA vaccination. The efficiency of DNA delivery directly affects its application in basic research and clinical setting. Traditionally, DNA delivery systems have been classified as viral vector-mediated systems and nonviral vector-mediated systems. Viral systems are by far the most effective means of DNA delivery, achieving high efficiencies (usually > 90%) for both delivery and expression. In fact, around 75% of recent clinical protocols involving gene therapy use recombinant viral-based vectors for DNA delivery. As yet, however no definitive evidence has been presented for the clinical effectiveness of any gene therapy protocol. The impotence of current methodology is attributable to the limitation of viral-mediated delivery, including toxicity, restricted targeting of specific cell line, limited DNA carrying capacity, production and packaging problems, recombination, and high cost. Furthermore, the toxicity and immunogenicity of viral systems also hamper their routine use. For these reasons, nonviral systems have become increasingly desirable in basic research and clinical settings. But nonviral delivery efficiency is always less than viral systems. With the rapid development of nanobiotechnology, nanoparticles-basednonviral-mediated systems will help, to alleviate the gene delivery bottle-neck, and achieve the ability to safe, efficient, and targeted DNA delivery, and provide the best means for gene structure,, function research, as well as clinical settings.In the previous study, Luo D & Saltzman WM used biocompatible silica nanoparticles, which by themselves do not deliver DNA, to concentrate DNA-transfection reagent complexes at the surface of cell monolayers and enhanced transfection efficiency by up to 8.5-fold over the best commercially available transfection reagents. Their results suggested if silica nanoparticles were modified with polycations, such as poly-1-lysine, they maybe achieve the ability to efficient deliver DNA and antisense ODN.In the current research, silica nanoparticles (SiNP) were synthesized firstly in a microemulsion system polyoxyethylene nonylphenyl ether (OP-10)/ cyclohexane/ ammonium hydroxide, at the same time the effects of SiNP size and its distribution were elucidated by orthogonal analysis; then poly-1-lysine (PLL) was linked on the surface of SiNP by nanoparticle surface energy and electrostatically binding; lastly a novel complex nanomaterial-poly-1-lysine-midified silica nanoparticles (PMS-NP) was prepared. The analysis of plasmid DNA binding and DNase I enzymatic degradation discovered that PMS-NP could bind DNA, and protect it against enzymatic degradation. Cell transfection showed PMS-NP couldefficiently transfer pEGFP-C2 or pSV-p-gal plasmid DNA into HNE1 or Hela cell line. These results indicated PMS-NP is a novel nanoparticulate carrier for plasmid DNA delivery, and would probably play an important role in gene structure and function research as well as gene therapy.Antisense oligonucleotides are single-stranded synthetic DNA sequences designed to be complementary to a specific gene. Hybridization with target pro-mRNA or mRNA through Watson-Crick base-pairing can block sterically the translation of this transcript, or activate RNase H-mediated degradation of the RNA strand in RNA-DNA heteroduplexes and subsequently inhibit gene expression at both mRNA and protein levels. Antisense as a potential therapeutic agent against neoplastic and infectious diseases has been tested in numerous research laboratories around the world. However, one of the crucial problems to broad application of antisense technology, the low intracellular penetration, has to be solved. In order to increase ODN intracellular delivery, to avoid non-specific aptameric effects, the use of particulate carriers such as liposomes or nanoparticles, may be considered as being the more realistic...
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