title: Characterization of a targeted gene carrier, lactose-polyethylene glycol-grafted poly-L-lysine and its complex with plasmid DNA.
abstract: The physicochemical properties and gene transfer ability of lactose-polyethylene glycol-grafted poly-L-lysine (Lac-PEG-PLL) were investigated. A dye displacement assay showed that plasmid DNA self-assembled with Lac-PEG-PLL, and condensation began at a <1:1 charge ratio of plasmid DNA to polymer. In atomic force microscopy, spontaneously assembled Lac-PEG-PLL/DNA complexes revealed a compact structure, with a size of about 100-200 nm. Circular dichroism spectra of Lac-PEG-PLL/DNA complexes revealed that the secondary structure of DNA was altered by complex formation and was similar to that of the poly-L-lysine/DNA complex. Lac-PEG-PLL was shown to protect DNA against nuclease action in a DNase I protection assay. The cytotoxicity test demonstrated that the complex composed of plasmid DNA and Lac-PEG-PLL had little influence on the viability of HepG2 cells, especially in comparison with that of poly-L-lysine/DNA complexes. In conclusion, our copolymer, Lac-PEG-PLI, formed complexes with plasmid DNA (on average, 150 nm), gave little cytotoxicity, and showed increased efficiency of gene transfer into hepatoma cells in vitro. Lactose-polyethylene glycol was grafted to poly-L-lysine to be used as a gene carrier for hepatoma cell targeting and to improve the solubility of the polyplexes. The average size of the carrier/DNA complexes was about 150 nm. The complexes also proved to have high resistance against nuclease attack and little cytotoxicity. The polymer also delivered plasmid DNA efficiently into a HepG2 cell line. Lac-PEG-PLL was more efficient than Lipofectin or galactose-PEG-PLL in transfection efficiency.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, South Korea.
authors.forename: Y H
authors.initials: YH
authors.lastname: Choi
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: J S
authors.initials: JS
authors.lastname: Choi
authors.forename: S W
authors.initials: SW
authors.lastname: Kim
authors.forename: J S
authors.initials: JS
authors.lastname: Park
mesh_terms: D001681:Biological Assay; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000628:therapy; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D004396:Coloring Agents / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D006801:Humans; D007785:Lactose / Q000737:chemistry; D008113:Liver Neoplasms / Q000235:genetics / Q000628:therapy; D018625:Microscopy, Atomic Force; D010957:Plasmids / Q000737:chemistry* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D004396:Coloring Agents; D011107:Polylysine; D011092:Polyethylene Glycols; D003850:Deoxyribonuclease I; D007785:Lactose