Simultaneous immobilization of gadolinium ions and di(o-carborano-1,2-dimethyl)borate on Fe3O4 nanoparticles

Neutron capture therapy is a promising method for cancer treatment based on targeted delivery of specific isotopes into cancer cells and subsequent irradiation with epithermal neutrons. As a result, a large amount of energy is released at a distance comparable to the size of the cell, destroying it from the inside. For the targeted delivery of isotopes, magnetic iron oxide nanoparticles can be used. In this article, iron oxide nanoparticles (Fe3O4) were modified with silanes and polyelectrolyte complexes for simultaneous immobilization of gadolinium ions and carborane compounds through ionic interaction for potential application in targeted delivery into cancer cells for neutron capture therapy. Structure, size and element composition was elucidated by Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDA), dynamic light scattering (DLS) and X-ray diffraction (XRD) analysis. It was found that according EDA, resulting nanoparticles consist of 15.4 % boron and 1.5 % gadolinium, with average hydrodynamical size of 386 nm measured by DLS. An in vitro cytotoxicity test using HepG2 (a cancer cell line) and human skin fibroblasts (a normal cell line) showed minor cytotoxicity in concentration range from 0.05 to 1 mg/mL.