RESUMEN
OBJECTIVE: To improve superparamagnetic iron oxide nanoparticles (SPIO-NP) stability, biocompatibility and tumor-targeting and evaluate their tumor targeting in vitro. METHODS: The folic acid-carboxymethylchitosan-superparamagnetic iron oxide nanoparticles (FA-OCMCS-SPIO-NPs) were synthesized by "three-steps": at first, superparamagnetic oxide iron nanoparticles were synthesized by coprecipitation, then, O-carboxymethyl chitosan and folic acid were successfully immobilized on the surface of SPIO-NPs in turn. The fourier transform infrared spectroscopy, X-Ray diffraction were used to confirm their synthesis, meanwhile, transmission electron microscope (TEM), dynamic light scattering (DLS), Zeta-potential measurement and vibrating sample magnetometry (VSM) were applied to characterize their physicochemical properies. Ferrozine assay and Prussian blue staining were used to evaluate their tumor targeting in vitro. RESULTS: X-Ray diffraction showed the crystalline powder of FA-CMCS-SPIO-NPs agree with the standard Fe3O4, Fourier transform infrared results showed O-carboxymethylchitosan and folic acid were covalently modified on the surface of SPIO-NPs successfully, TEM showed all synthesized SPIO-NPs were almost spherical or ellipsoidal. Their sizes were less then 20 nm, dynamic light scattering (DLS), Zeta-potential results demonstrate the intensity particle size distributions of FA-OCMCS-SPIO-NPs were (41.4±0.132)nm, Zeta potential were (-21.36±15)mV. The surface modification may lead to decrese of magnetisms Ferrozine assay and Prussian blue staining results showed FA-OCMCS-SPIO-NPs had good tumor targeting and the tumor targeting had good relations with the amount of FR on surface of tumor cells. CONCLUSION: FA-OCMCS-SPIO-NPs with strong superparamagnetic property, excellent stability, and good folate receptor targeting is successfully synthesized, which demonstrated the potential for tumor MRI diagnose and therapy.