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.
Material and 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.