Optimization of the surface immobilized folate on the magnetic nanoparticles

Cancer cells overexpressing folate receptors have been targeted using a folate decorated carriers for anti-cancer drugs in aims to overcome the tissue non-specificity of anti-cancer agents. We here prepared magnetic nanoparticles and surface-decorated them with different amounts of folate to optimize the number of the immobilized folate on the carriers for superior targeting effects. Magnetic nanoparticles were prepared by oxidizing ferric or ferrous chloride solution to iron oxide in the presence of poly(vinyl alcohol). The magnetic nanoparticles were functionalized with primary amines for subsequent reactions with the different feed ratios of the activated folate. The magnetization degree of the folate magnetic magnetization were slightly decreased when the folate on the particles were increased. Intracellular uptakes of the nanoparticles were shown to be increased and become saturated dependent on the amounts of the surface-immobilized folate. The folate-decorated magnetic nanoparticles showed negligible cytotoxicity against KB cells from 5 μg to 35 μg of the nanoparticle weights.