Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field

Abstract

New approaches to increase the efficiency of non-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) containing sequence encoding for green fluorescent protein were coupled to polyethylenimine coated superparamagnetic nanoparticles (SPIONs). The complexes were added to cells that were subsequently exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency 40 times more than in cells not exposed to the magnetic field. The transfection efficiency was highest when the nanoparticles were sedimented on the permanent magnet before the application of the pulsating field, both for small (50 nm) and large (200–250 nm) nanoparticles. The highly efficient gene transfer already within 5 min shows that this technique is a powerful tool for future in vivo studies, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.

Control of aggregate size of polyethyleneimine-coated magnetic nanoparticles for magnetofection

“…6), lower than the transfection with PEI alone. This is in accordance with the previous report from Kamau et al [10]. Because the transfections of the cells were only enhanced when placed on a magnetic plate, it is clear that the key role of MP-PEI in magnetofection lies in drawing the DNA-PEI complexes onto the surface of the cells via the magnetic force.…”

“…Besides bioconjugation, a much more simple method involves using positively charged magnetic particles to couple with nuclear acids via electrostatic interactions [10,11]. One of the most widely used positively charged modification agents is polyethyleneimine (PEI) which is capable of forming complexes with DNA and condensing them into compact nanoparticles [12,13].…”

“…For example, Plank and co-workers synthesized magnetic particles in situ in PEI solutions [8,15,16], Hottiger and coworkers directly mixed maghemite dispersions with PEI solutions [10], whilst McBain and co-workers exploited covalent bonds to attach PEI to magnetic particles [17]. The MP-PEI prepared by these methods are all capable of enhancing gene delivery.…”

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

“…A number of cationic polymers (e.g. poly(ethylene imine) [85] and poly(dimethyaminoethyl (meth)acrylate) [86]) have been grafted onto IONPs and used for conjugation with siRNA via electrostatic interactions. Pan et al [85] developed PEI-coated IONPs for the encapsulation of genes and demonstrated successful in vitro delivery.…”

“…Magnetic cores have been exploited for enhanced transfection under a magnetic field (magnetofection) [37]. Kamau et al [86] functionalized IONPs with PEI for gene delivery applications and studied their transfection efficiency under an applied magnetic field in vitro. On exposure to permanent and oscillating magnetic fields, the in vitro transfection efficiency was 40 times higher than in the absence of a magnetic fi eld.…”