A magnetic nanocomposite, consisting of Fe3O4 nanoparticles embedded into a Mg/Al layered double hydroxide (LDH) matrix, was developed for cancer multimodal therapy, based on the combination of local magnetic hyperthermia and thermally induced drug delivery. The synthesis procedure involves the sequential hydrolysis of iron salts (Fe2+, Fe3+) and Mg2+/Al3+ nitrates in a carbonate-rich mild alkaline environment followed by the loading of 5-fluorouracil, an anionic anticancer drug, in the interlayer LDH space. Magnetite nanoparticles with a diameter around 30 nm, dispersed in water, constitute the hyperthermia-active phase able to generate a specific loss of power of around 500 W/g-Fe in an alternating current (AC) magnetic field of 24 kA/m and 300 kHz as determined by AC magnetometry and calorimetric measurements. Heat transfer was found to trigger a very rapid release of drug which reached 80% of the loaded mass within 10 min exposure to the applied field. The potential of the Fe3O4/LDH nanocomposites as cancer treatment agents with minimum side-effects, owing to the exclusive presence of inorganic phases, was validated by cell internalization and toxicity assays.
Keywords: Fe3O4; cell internalization; continuous flow synthesis; drug delivery; layered double hydroxide; magnetic hyperthermia; nanocomposite.