title: [Cationic lipid and polyethylene glycol enhance liposomes-mediated cell transfection and increase the fluidity of liposomes membranes].
abstract: OBJECTIVE
  To prepare fluorescein sodium (FS) cationic liposomes and investigate the influence of cationic lipid (DC-chol) and polyethylene glycol (PEG) with different molecule weight (MW) on cationic liposome incorporation efficiency, cellular delivery and fluidity of liposome membrane.
  
  
  METHODS
  Using FS as a model material for encapsulation, the liposomes were prepared and separated (by sephadex G-50 1 cm x 20 cm column), and the liposome incorporation efficiencies was measured. The interaction between the FS and cationic liposomes was investigated by measuring the change of fluorescent spectrum. The cellular uptake of different liposome forms by choosing HepG2 2.2.15 as an in vitro cell culture assay model, and the influence of PEG on the fluidity of liposome membrane with the technique of fluorescence polarization were investigated.
  
  
  RESULTS
  Cationic lipid and different PEGs showed great effects on increasing liposome incorporation efficiency (from 0.64% to 86.57%), cellular uptake (from 2.18% to 48.46%) and fluidity of liposome membrane. The effect of PEG was MW dependent, and with the increase of MW, the incorporation efficiency and transfection was improved, and the fluidity of liposome membrane increased.
  
  
  CONCLUSIONS
  Addition of cationic lipid and high MW PEG into cationic liposomes can enhance the cellular delivery and fluidity of cationic liposomes. Also, they can improve the incorporation efficiency of cationic liposomes.
authors.affiliation: Department of Pharmaceutics, School of Pharmaceutical Science, Peking University, Beijing 100083, China.
authors.forename: Wen-wei
authors.initials: WW
authors.lastname: Yan
authors.forename: Xian-rong
authors.initials: XR
authors.lastname: Qi
authors.forename: Lai
authors.initials: L
authors.lastname: Wei
authors.forename: Ran
authors.initials: R
authors.lastname: Fei
authors.forename: Xu
authors.initials: X
authors.lastname: Cong
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002784:Cholesterol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D016503:Drug Delivery Systems; D019793:Fluorescein; D018197:Hepatoblastoma / Q000473:pathology; D006801:Humans; D008081:Liposomes; D008113:Liver Neoplasms / Q000473:pathology; D008560:Membrane Fluidity / Q000187:drug effects*; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology*; D014162:Transfection / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: D008081:Liposomes; C070648:3-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol; D011092:Polyethylene Glycols; D002784:Cholesterol; D019793:Fluorescein