title: A cationic lipid emulsion/DNA complex as a physically stable and serum-resistant gene delivery system.
abstract: OBJECTIVE
  To develop a non-viral gene delivery system in the form of an oil-in-water (o/w) lipid emulsion.
  
  
  METHODS
  Cationic lipid emulsions were formulated with soybean oil, 1,2-dioleoyl-sn-glycero-3-trimethylammonium-propane (DOTAP) as a cationic emulsifier and other co-emulsifiers. The physical characteristics of the lipid emulsion and the emulsion/DNA complex were determined. The in vitro transfection efficiency of the emulsion/DNA complex was determined in the presence of up to 90% serum.
  
  
  RESULTS
  The average droplet size and zeta potential of emulsions were ca. 180 nm and ca. +50 mV, respectively. Among the emulsions, a stable formulation was selected to form a complex with a plasmid DNA encoding chloramphenicol acetyltransferase. By increasing the ratio of emulsion to DNA. zeta-potential of the emulsion/DNA complex increased monotonously from negative to positive without any changes in the complex size. The complex was stable against DNase I digestion and an anionic poly-L-aspartic acid (PLAA). The complex delivered DNA into the cells successfully, and the transfection efficiency was not affected by complex formation time from 20 min to 2 h. More importantly, the cationic lipid emulsion facilitated the transfer of DNA in the presence of up to 90% serum.
  
  
  CONCLUSIONS
  The cationic lipid emulsion/DNA complex has physical stability and serum resistant properties for gene transfer.
authors.affiliation: Biomedical Research Center, Korea Institute of Science and Technology, Seoul.
authors.forename: S W
authors.initials: SW
authors.lastname: Yi
authors.forename: T Y
authors.initials: TY
authors.lastname: Yune
authors.forename: T W
authors.initials: TW
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Chung
authors.forename: Y W
authors.initials: YW
authors.lastname: Choi
authors.forename: I C
authors.initials: IC
authors.lastname: Kwon
authors.forename: E B
authors.initials: EB
authors.lastname: Lee
authors.forename: S Y
authors.initials: SY
authors.lastname: Jeong
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001798:Blood Proteins / Q000494:pharmacology*; D019556:COS Cells; D002412:Cations / Q000493:pharmacokinetics; D002795:Choline O-Acetyltransferase / Q000235:genetics; D003851:Deoxyribonucleases; D004586:Electrophoresis; D004655:Emulsions; D018014:Gene Transfer Techniques; D005990:Glycerol / Q000493:pharmacokinetics; D010455:Peptides; D010957:Plasmids; D011092:Polyethylene Glycols / Q000493:pharmacokinetics*; D013024:Soybean Oil / Q000493:pharmacokinetics*; D014162:Transfection; D014867:Water
chemical_list: D001798:Blood Proteins; D002412:Cations; D004655:Emulsions; D010455:Peptides; D014867:Water; C017645:polyaspartate; D011092:Polyethylene Glycols; D013024:Soybean Oil; D002795:Choline O-Acetyltransferase; D003851:Deoxyribonucleases; D005990:Glycerol