A simple approach to synthetize folic acid decorated magnetite@SiO₂ nanostructures for hyperthermia applications

Superparamagnetic magnetite nanoparticles were synthetized and capped by a SiO₂ shell in order to avoid oxidation and aggregation of the iron oxide nanostructures. The inorganic capping was then further decorated by folic acid molecules, by using a very simple procedure exploiting supramolecular interactions among the organic moieties and the inorganic nanoparticles. The supramolecular nanoadduct thanks to folic acid molecules could act as a "Trojan horse" for the cancer cells and due to its superparamagnetic properties could induce local heat generation upon an appropriate magnetic field application. In fact, temperature was increased up to 42 °C when a 18 mT magnetic field was applied to the nanoparticles and the hybrid nanostructures were verified to be selectively internalized by HeLa cells, a human cervical cancer line known to overexpress the folic acid receptor.