Magnetic nanoparticles (MNPs) are a class of materials that can be manipulated under the influence of an external magnetic field. Thanks to the ability of the MNPs to be guided by an external magnetic field that is like "action at a distance", combined with their low cytotoxicity and the intrinsic penetrability of magnetic fields into human tissue, opens up many applications involving the transport and/or immobilization of biological entities [1, 2].

This work is focused on the synthesis of magnetite nanoparticles by varied methods, their functionalization with nickel tetrasulfonated phthalocyanine, and the corresponding physicochemical characterization and colloidal stability studies in biologically compatible media. The in vitro production of singlet oxygen by these nanoparticles through photochemical stimulation in ultraviolet and visible region was evaluated, resulting in 4.5 and 4 µM respectly to magnetite synthetized in the group. The increase reactive oxygen species concentration in the cellular environment can result in modification and damage of cellular components, and potentially, cell death and necrosis. Therefore, these materials offer the promise of revolutionary tools for photodynamic therapy and hyperthermia, which are attractive strategies for cancer therapy without systemic toxicity.