Insights into the mechanism of magnetic particle assisted gene delivery

In magnetic particle assisted gene delivery DNA is complexed with polymer-coated aggregated magnetic nanoparticles (AMNPs) to effect transfection. In vitro studies based on COS-7 cells were carried out using pEGFP-N1 and pMIR-REPORT-complexed, polyethylenimine (PEI)-coated iron oxide magnetic nanoparticles (MNPs). PEI-coated AMNPs (PEI–AMNPs) with average individual particle diameters of 8, 16 and 30 nm were synthesized. Normal, reverse and retention magnetic transfection experiments and cell wounding assays were performed. Our results show that the optimum magnetic field yields maximum transfection efficiency with good viability. The results of the normal, reverse and retention magnetic transfection experiments show that the highest transfection efficiency was achieved in normal magnetic transfection mode due to clustering of the PEI–AMNPs on the cells. Cell wounding assay results suggest that the mechanism of magnetic transfection is endocytosis rather than cell wounding.