title: Comparison of two kinds of nanomedicine for targeted gene therapy: premodified or postmodified gene delivery systems.
abstract: BACKGROUND
  The applications of ligand-polyethylene glycol (PEG)-modified nanocarriers have now emerged, as well as recognized strategies to provide the vectors with active targeting properties. In this research, premodification and postmodification were compared using the same ligand, ie, a novel conjugated mannan-containing PEG and L-α-phosphatidylethanolamine (PE).
  
  
  METHODS
  Premodified and postmodified solid lipid nanoparticles were prepared and the characteristics of the two kinds of vehicles were evaluated. The modified vectors were then administered intravenously to rats and the in vivo targeting behavior of the complexes was investigated in liver macrophages.
  
  
  RESULTS
  By carefully formulating the carriers with an optimal ratio of mannan-containing PEG-PE, postmodified vehicles displayed more efficient gene expression in rat Kupffer cells both in vitro and in vivo.
  
  
  CONCLUSIONS
  Postmodified gene carriers are superior to premodified gene vectors, although the latter is also promising for targeted gene delivery. This discovery could guide our future research.
authors.affiliation: General Hospital of Ji'nan Command, PLA, Ji'nan, Shandong, China.
authors.forename: Zhaoshun
authors.initials: Z
authors.lastname: Jiang
authors.forename: Cong
authors.initials: C
authors.lastname: Sun
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Yin
authors.forename: Fang
authors.initials: F
authors.lastname: Zhou
authors.forename: Linfu
authors.initials: L
authors.lastname: Ge
authors.forename: Ximin
authors.initials: X
authors.lastname: Liu
authors.forename: Fansheng
authors.initials: F
authors.lastname: Kong
mesh_terms: D000818:Animals; D004247:DNA / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage; D066298:In Vitro Techniques; D007728:Kupffer Cells / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008297:Male; D008351:Mannans / Q000737:chemistry; D050997:Nanomedicine; D053758:Nanoparticles / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection
chemical_list: D004337:Drug Carriers; D008055:Lipids; D008351:Mannans; D010714:Phosphatidylethanolamines; C067972:dioleoyl-N-(monomethoxypolyethylene glycol succinyl)phosphatidylethanolamine; D011092:Polyethylene Glycols; D004247:DNA