Amphipathic polymer pullulan acetate (PA)-coated magnetic nanoparticles were prepared and characterized by various physicochemical means. The cytotoxicity and cellular uptake of the magnetic nanoparticles were examined. The hyperthermic effect of the magnetic nanoparticles on tumor cells was evaluated. Transmission electron microscopy (TEM) showed that the PA coated magnetic nanoparticles (PAMNs) had spherical morphology. Dynamic light scattering (DLS) showed that the size distribution of PAMNs was unimodal,with an average diameter of 25.8 nm ± 6.1 nm. The presence of the adsorbed layer of PA on the magnetite surface was confirmed by Fourier transform infrared (FTIR) spectroscopy. Magnetic measurements revealed that the saturation magnetization of the PAMNs reached 51.9 emu/g and the nanoparticles were superparamagnetic. Thermogravimetric analysis (TGA) showed that the Fe_(3)O_(4) particles constituted 75 wt% of the PAMNs. The PAMNs had good heating properties in an alternating magnetic field. Cytotoxicity assay showed that PAMNs exhibited no significant cytotoxicity against L929 cells. TEM results showed that a large number of PAMNs were internalized into KB cells. PAMNs have good hyperthermia effect on KB cells in vitro by magnetic field induced hyperthermia. These novel magnetic nanoparticles have great potential as magnetic hyperthermia mediators.
