Facile synthesis of low toxicity iron oxide/TiO₂ nanocomposites with hyperthermic and photo-oxidation properties

The present study aimed to assess the feasibility of developing low-cost multipurpose iron oxide/TiO₂ nanocomposites (NCs) for use in combined antitumor therapies and water treatment applications. Larger size (≈ 100 nm) iron oxide nanoparticles (IONPs) formed magnetic core-TiO₂ shell structures at high Fe/Ti ratios and solid dispersions of IONPs embedded in TiO₂ matrices when the Fe/Ti ratio was low. When the size of the iron phase was comparable to the size of the crystallized TiO₂ nanoparticles (≈ 10 nm), the obtained nanocomposites consisted of randomly mixed aggregates of TiO₂ and IONPs. The best inductive heating and ROS photogeneration properties were shown by the NCs synthesized at 400 °C which contained the minimum amount of α-Fe₂O₃ and sufficiently crystallized anatase TiO₂. Their cytocompatibility was assessed on cultured human and murine fibroblast cells and analyzed in relation to the adsorption of bovine serum albumin from the culture medium onto their surface. The tested nanocomposites showed excellent cytocompatibility to human fibroblast cells. The results also indicated that the environment (i.e. phosphate buffer or culture medium) used to disperse the nanomaterials prior to performing the viability tests can have a significant impact on their cytotoxicity.