Intracellular uptake of poly(ethylene glycol) and folic acid modified magnetite nanoparticles

Superparamagnetic magnetite nanoparticles were surface-modified with poly(ethylene glycol) (PEG) or folic acid, to resist the protein adsorption and avoid their recognition by macrophage cells, and to improve their cell internalization and ability to target specific cells. The nanoparticle uptake into human osteosarcoma cells, MG63, was visualized using both fluorescence and confocal microscopy, and quantified using inductively coupled plasma emission spectroscopy (ICP) measurement. Fluorescence and confocal microscopy results showed that the nanoparticles were internalized into the cells after the cells were cultured for 48h in the medium containing the nanoparticles modified with PEG or folic acid. ICP measurements indicated that both the PEG and folic acid modification increased the amount of the nanoparticle uptake into the cells, in comparison with that of unmodified nanoparticles.