Multifunctional polyglycerol-grafted Fe3O4@SiO2 nanoparticles for targeting ovarian cancer cells

Ligand-mediated magnetic resonance (MR) contrast agents would be highly desirable for cancer diagnosis. In the present study, nanoparticles of Fe3O4 core with fluorescent SiO2 shell were synthesized and grafted with hyperbranched polyglycerol (HPG-grafted Fe3O4@SiO2 nanoparticles). These nanoparticles have a hydrodynamic diameter of 47.0 ± 4.0 nm, and are very stable in aqueous solution as well as in cell culture medium. Numerous surface hydroxyl groups of these nanoparticles were conjugated with folic acid by a thiol 'click' reaction. The successful covalent attachment of folic acid on the nanoparticles was confirmed by FTIR and XPS analyses. Both MR imaging and fluorescence microscopy show significant preferential uptake of the folic acid-conjugated polyglycerol-grafted Fe3O4@SiO2 (FA-HPG-grafted Fe3O4@SiO2) nanoparticles by human ovarian carcinoma cells (SKOV-3) as compared to macrophages and fibroblasts. Such nanoparticles can potentially be used to provide real-time imaging in ovarian cancer resection.