title: A novel approach for nucleic acid delivery into cancer cells.
abstract: BACKGROUND
  Liposomal magnetofection is based on the use of superparamagnetic particles and cationic lipids and shows better transfection efficiency than other common nonviral gene delivery methods; however, the distribution of aggregate complexes over the cell surface may be ununiform. The use of a dynamic gradient magnetic field could overcome this limitation. A newly developed device for magnetofection under a dynamic magnetic field was used to compare the transfection efficiency of prostate carcinoma cell line PC3 with that obtained by lipofection and magnetofection.
  
  
  METHODS
  Reporter plasmid pcDNA3.1LacZ DNA was used in combination with Lipofectamine2000 reagent and superparamagnetic nanoparticles CombiMag. The effects of incubation time under a dynamic magnetic field and a rotation frequency of magnets on transfection efficiency for PC3 cell line were determined. Alternatively, lipofection and liposomal magnetofection were carried out. Transfection efficiency of delivery methods was estimated by β-galactosidase staining; cell viability, by acridine orange/ethidium bromide staining.
  
  
  RESULTS
  Liposomal magnetofection under a dynamic gradient magnetic field demonstrated the highest transfection efficiency: it was greater by almost 21% and 42% in comparison with liposomal magnetofection and lipofection, respectively. The optimal incubation time under dynamic magnetic field and the optimal magnet rotation frequency were 5 minutes and 5 rpm, respectively. Liposomal magnetofection under a dynamic gradient magnetic field was less cytotoxic (7%) than that under a permanent magnetic field (17%) and lipofection (11%).
  
  
  CONCLUSIONS
  Our new approach, based on the use of a dynamic gradient magnetic field, enhanced the transfection efficiency and had a less cytotoxic effect on prostate cancer cells in comparison with the standard magnetofection and lipofection.
authors.affiliation: August Kirchenstein Institute of Microbiology and Virology, Riga Stradins University, Ratsupites 5, 1067 Riga, Latvia. d.vainauska@inbox.lv
authors.forename: Dace
authors.initials: D
authors.lastname: Vainauska
authors.forename: Svetlana
authors.initials: S
authors.lastname: Kozireva
authors.forename: Andrejs
authors.initials: A
authors.lastname: Karpovs
authors.forename: Maksims
authors.initials: M
authors.lastname: Čistjakovs
authors.forename: Mihails
authors.initials: M
authors.lastname: Bariševs
mesh_terms: D045744:Cell Line, Tumor; D004247:DNA / Q000008:administration & dosage*; D006801:Humans; D008081:Liposomes; D060526:Magnetic Fields; D058185:Magnetite Nanoparticles / Q000008:administration & dosage*; D009369:Neoplasms / Q000628:therapy*; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D014162:Transfection / Q000379:methods*
chemical_list: D008081:Liposomes; D058185:Magnetite Nanoparticles; D034741:RNA, Small Interfering; D004247:DNA