title: Water-soluble and low molecular weight chitosan-based plasmid DNA delivery.
abstract: OBJECTIVE
  Chitosan, a natural cationic polysaccharide, is a candidate non-viral vector for gene delivery because of its high positive charges and low cytotoxicity. In this study, low molecular weight chitosan (LMWC, molecular weight of 22 kDa) was characterized and evaluated as a gene carrier.
  
  
  METHODS
  Plasmid/LMWC complex was analyzed in 1% agarose gel electrophoresis. To confirm that the LMWC protected plasmids from nuclease. DNase I protection assays were performed. pSV-beta-galactosidase plasmid/LMWC complex was transfected into 293T cells and transfection efficiency was evaluated by beta-galactosidase assay. Cytotoxicity of LMWC was determined by MTT assay.
  
  
  RESULTS
  Unlike high molecular weight chitosan (HMWC), LMWC is highly water soluble, and can form complex with plasmids in physiological buffer. The plasmid DNA was completely retarded at a weight ratio of 1:2 (plasmid:LMWC) in 1% agarose gel. DNase I protection assay showed that plasmids were protected from DNase-I over 60 min. The most efficient transfection was obtained at a weight ratio of 1:3 (plasmid:LMWC). The transfection efficiency of LMWC was significantly higher than naked DNA and higher than poly-L-lysine (PLL). MTT assay showed that LMWC was less cytotoxic than PLL.
  
  
  CONCLUSIONS
  LMWC is non-toxic and has higher transfection efficiency than PLL. Therefore, LMWC will be useful in the development of safe gene carriers.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City 84112-5820, USA. minhyung.lee@deans.pharm.utah.edu
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.forename: J W
authors.initials: JW
authors.lastname: Nah
authors.forename: Y
authors.initials: Y
authors.lastname: Kwon
authors.forename: J J
authors.initials: JJ
authors.lastname: Koh
authors.forename: K S
authors.initials: KS
authors.lastname: Ko
authors.forename: S W
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002460:Cell Line; D002686:Chitin / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000235:genetics; D048271:Chitosan; D004247:DNA / Q000008:administration & dosage* / Q000235:genetics; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D010957:Plasmids / Q000008:administration & dosage* / Q000235:genetics; D014162:Transfection / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; C400945:water soluble chitin; D002686:Chitin; D004247:DNA; D048271:Chitosan