title: Design and characterization of a novel lipid-DNA complex that resists serum-induced destabilization.
abstract: Ineffectiveness of cationic lipids to enhance DNA transfection has been attributed to serum-mediated dissociation and perhaps complement activation of lipid-DNA complexes. To overcome these problems, we have developed a novel lipid-DNA complex that greatly reduces serum-mediated dissociation. The complexes were prepared by mixing cationic liposomes containing 1,2-dioleoyl-3-trimethylammonium-propane and dioleoylphosphatidyl-ethanolamine and DNA in ethanolic (20% v/v ethanol) solution containing 5% sucrose followed by dehydration via rotating evaporation. Upon hydration in H(2)O, the lipid-DNA complexes [ethanol-dried lipid-DNA (EDL) complexes] were formed. The complexes exhibit a low positive zeta potential and enhanced transfection efficiency in contrast to the suppressed efficiency detected with admixed lipid-DNA complexes in the presence of serum across several cell lines. This result may be attributed to the inability of serum to dissociate DNA from lipids in EDL complexes. Using displacement of ethidium bromide intercalation analysis, we found that in serum, only 50% of DNA was exposed in the EDL complexes, compared with 100% in the admixed lipid-DNA complexes. The EDL complexes also showed increased resistance to DNase digestion in the presence of negatively charged lipid, while reducing complement activation in serum. The EDL complexes may improve the transfection activity of lipid-DNA complexes in serum and, perhaps, in vivo.
authors: Department of Pharmaceutics, University of Washington, Box 357610 H272 Health Sciences Building, Seattle, Washington 98195, USA.
authors: Tianshun
authors: T
authors: Lian
authors: Rodney J Y
authors: RJ
authors: Ho
mesh_terms: D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D018938:Caco-2 Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D004247:DNA / Q000138:chemical synthesis / Q000493:pharmacokinetics* / Q000648:ultrastructure; D015195:Drug Design; D004355:Drug Stability; D015316:Genetic Therapy / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D008055:Lipids / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D008081:Liposomes; D044967:Serum / Q000502:physiology*; D013678:Technology, Pharmaceutical / Q000379:methods*; D014162:Transfection / Q000379:methods*
chemical_list: D008055:Lipids; D008081:Liposomes; D004247:DNA