Plasma synthesis of carbon-iron magnetic nanoparticles and immobilization of doxorubicin for targeted drug delivery

A novel dense-medium plasma technology (submerged arc discharge) was used to synthesize carbon/iron-based magnetic nanoparticles (CMNP) from benzene or acetonitrile at room temperature and atmospheric pressure. Scanning electron microscopy shows that the nanoparticles are spherical and 40–50 nm in diameter. Results from x-ray photoelectron spectroscopy and other analytical techniques demonstrated that the CMNP consist of iron/iron oxide clusters that are evenly dispersed in a carbon-based host-structure. After synthesis, CMNP samples were activated in three steps: argon plasma treatment, in-situ reactions with ethylene diamine, and substrate activation by glutaric dialdehyde. Free doxorubicin (DOX) molecules were then immobilized onto the activated CMNP surfaces to form CMNP-DOX conjugates. The loading efficiency of doxorubicin was determined. In vitro anti-proliferative activity of CMNP-DOX conjugates was confirmed in tumor-cell cytotoxicity assays. It is therefore suggested that CMNP may be used as a magnetic carrier for targeted drug-delivery applications.