title: Enhancement of polyethylene glycol (PEG)-modified cationic liposome-mediated gene deliveries: effects on serum stability and transfection efficiency.
abstract: In this study, we modified cationic liposomes either by polyethylene glycol (PEG)-grafting or PEG-adding methods, and compared the physical properties of transfection complexes and transfection efficiency in-vitro and prolonged circulation in-vivo. The PEG-grafted transfection complexes were prepared by mixing plasmid DNA with PEG-grafted cationic liposomes, which were composed of DSPE-PEG 2000 and cationic lipids. The PEG-added transfection complexes were prepared by adding DSPE-PEG 2000 to the mixture of cationic liposomes and plasmid DNA. The particle sizes of the PEG-modified transfection complexes (approximately 200 nm) changed a little over 4 weeks compared with the conventional transfection complexes. In the presence of serum, the transfection efficiency of the conventional transfection complexes was lowered whereas the transfection efficiency of the PEG-modified transfection complexes was maintained. Moreover, the transfection efficiency of the conventional transfection complexes was significantly reduced when they were stored. However, the transfection efficiency was stable for the PEG-modified transfection complexes, even after two weeks of storage. Of the in-vitro transfection efficiencies, there was no difference between PEG-grafted and PEG-added transfection complexes. When the conventional, PEG-grafted, and PEG-added transfection complexes were administered into mice by the tail vein, the PEG-added transfection complexes showed a prolonged circulation of plasmid DNA compared with other transfection complexes. These results suggest that the PEG-added transfection complexes could be a useful non-viral vector because of their simplicity in preparation, enhanced stability and prolonged circulation compared with the conventional transfection complexes.
authors.affiliation: College of Pharmacy, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
authors.forename: Jin-Ki
authors.initials: JK
authors.lastname: Kim
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Choi
authors.forename: Cheong-Ok
authors.initials: CO
authors.lastname: Kim
authors.forename: Jeong-Sook
authors.initials: JS
authors.lastname: Park
authors.forename: Woong-Shick
authors.initials: WS
authors.lastname: Ahn
authors.forename: Chong-Kook
authors.initials: CK
authors.lastname: Kim
mesh_terms: D002412:Cations; D045744:Cell Line, Tumor; D004247:DNA / Q000493:pharmacokinetics; D017931:DNA Primers; D016503:Drug Delivery Systems; D005434:Flow Cytometry; D006801:Humans; D008081:Liposomes / Q000097:blood / Q000378:metabolism*; D010316:Particle Size; D010957:Plasmids / Q000235:genetics*; D011092:Polyethylene Glycols / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D014162:Transfection / Q000379:methods
chemical_list: D002412:Cations; D017931:DNA Primers; D008081:Liposomes; D011092:Polyethylene Glycols; D004247:DNA