title: Bacterial magnetic particles (BMPs)-PEI as a novel and efficient non-viral gene delivery system.
abstract: BACKGROUND
  Non-viral methods of gene delivery, especially using polyethylenimine (PEI), have been widely used in gene therapy or DNA vaccination. However, the PEI system has its own drawbacks, which limits its applications.
  
  
  METHODS
  We have developed a novel non-viral delivery system based on PEI coated on the surface of bacterial magnetic nanoparticles (BMPs). The ability of BMPs-PEI complexes to bind DNA was determined by retardation of plasmid DNA in agarose gel electrophoresis. The transfection efficiency of BMPs-PEI/DNA complexes into eukaryotic cells was determined by flow cytometric analysis. The MTT assay was invited to investigate the cytotoxicity of BMPs-PEI/DNA complexes. The expression efficiency in vivo of BMPs-PEI bound to the plasmid pCMVbeta encoding beta-galactosidase was evaluated intramuscularly inoculated into mice. The immune responses of in vivo delivery of BMPs-PEI bound plasmid pcD-VP1 were determined by MTT assay for T cell proliferation and ELISA for detecting total IgG antibodies.
  
  
  RESULTS
  BMPs-PEI complexes could bind DNA and provide protection from DNase degradation. The transfection efficiency of BMPs-PEI/DNA complexes was higher than that in PEI/DNA complexes. Interestingly, in contrast to PEI, the BMPs-PEI complex was less cytotoxic to cells in vitro. We further demonstrated that the BMPs-PEI system can deliver an exogenous gene to animals and allow it to be expressed in vivo. Such expression resulted in higher levels of humoral and cellular immune responses against the target antigen compared to controls.
  
  
  CONCLUSIONS
  We have developed a novel BMPs-PEI gene delivery system with a high transfection efficiency and low toxicity, which presents an attractive strategy for gene therapy and DNA vaccination.
authors.affiliation: State Key Laboratories for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100094, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiang
authors.forename: Wang
authors.initials: W
authors.lastname: Bin
authors.forename: Jin
authors.initials: J
authors.lastname: Huali
authors.forename: Jiang
authors.initials: J
authors.lastname: Wei
authors.forename: Tian
authors.initials: T
authors.lastname: Jiesheng
authors.forename: Guan
authors.initials: G
authors.lastname: Feng
authors.forename: Li
authors.initials: L
authors.lastname: Ying
mesh_terms: D000818:Animals; D016466:CHO Cells; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D006224:Cricetinae; D003412:Cricetulus; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008280:Magnetics; D042201:Magnetospirillum / Q000254:growth & development / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D011094:Polyethyleneimine; D011401:Promoter Regions, Genetic / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D036022:Capsid Proteins; C442501:VP1 protein, Foot-and-mouth disease virus; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D011094:Polyethyleneimine; D008156:Luciferases; D001616:beta-Galactosidase