Effective gene delivery into primary dendritic cells using synthesized PDMAEMA-iron oxide nanocubes

Dendritic cells (DCs) have been a target of vaccine delivery, gene therapy, and cancer immunotherapy. However, gene delivery to primary DCs using traditional non-viral molecules has been a difficult challenge. Herein we have developed a gene delivery system to primary DCs using magnetic iron oxide nanocubes (MCs) coated with cationic polymer under the induction of a magnetic field. The MCs were coated with positively charged polymer, poly(2-dimethylamino) ethyl methacrylate (MCs-PD) before the plasmid gene (pMAX-GFP) was adsorbed on their surfaces. Three different sizes (15, 40 and 90 nm) of MCs were synthesized, and subsequently, PDMAEMA was assembled onto the MC surfaces (MCs-PD). MCs-PD exhibited zeta potentials of +23 to +26 mV, and the obtained particles showed superparamagnetic character with saturation magnetization of 17–66 emu/g. The MCs-PD of 10–100 μg/mL showed low toxicity on bone marrow-derived dendritic cells (BMDCs) in MTT assay, and they were well taken up by BMDCs under a magnetic field. Moreover, the particles with small size exhibited the enhanced plasmid transfection efficiency without the activation of BMDCs. The MCs-PD could be a promising non-viral gene delivery system that helps to manipulate primary DCs in vitro, which will be beneficial for cell-based immunotherapy.