| Monodisperse magnetic nanoparticles （MNPs） were prepared through an organicphase process, and the obtained MNPs were capped withpoly[2-（2-methoxyethoxy）ethyl methacrylate]-b-poly [2-（dimethylamino） ethylmethacrylate] synthesized by surface-initiated atom transfer radical polymerization（ATRP）. The MNPs-polymer brushes exhibited both superparamagnetic andthermoresponsive behaviors. HRTEM, magnetic properties, TGA, FTIR and LCSTwere used to confirm the successful preparation of MNPs-polymer brushes. The novelcationic vector was capable of condensing plasmid DNAwith diameters less than200nm, which was determined by gel terardation assay, TEM and DLS. The studiesshowed that MNPs@PMEO2MA50-PDMAEMA150had a better ability to condenseand protect DNA. pGL3and pEGFP-C1plasmids were used as reported gene toevaluate the transfection efficacy in COS-7cells and HepG-2cells. The resultsindicated that the transfection efficiencies of polymer brushed-MNPs werecomparable or superior to that of PEI25k under combined temperature magneticstimuli. MTT assay showed the polymer brushes-MNPs and the complexes were lesscytotoxic than PEI25k over the best transfection complex ratio. It is anticipated thatmagnetofection combined with a temperature stimulus will offer a facile strategy toenhance the transfection efficiency of a nonviral vector. |
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