siRNA delivery by magnetofection.

Magnetofection is defined as the magnetically enhanced delivery of nucleic acids associated with magnetic nanoparticles and has been utilized to deliver synthetic siRNAs to cultured cells. Certain magnetic nanomaterials associate with siRNAs and are suitable for siRNA delivery, either alone or in combination with cationic polymers or cationic lipid enhancers; these complexes are targeted to the cell surface by application of a gradient magnetic field. In this review methods are described to examine siRNA incorporation into magnetic complexes, to evaluate their magnetic responsiveness and to characterize their association with, and uptake into cells. These methods can be utilized to screen magnetic siRNA complexes for their suitability in functional siRNA delivery. Data, obtained since the first description of magnetofection in 2000, and novel results on the characterization of magnetic complexes containing synthetic siRNA are described. In addition, the benefits of siRNA delivery in vitro via magnetofection compared with standard non-magnetic methods of transfection using lipoplexes and polyplexes are highlighted.