Bioactive magnetic nanoparticles of Fe-Ga synthesized by sol-gel for their potential use in hyperthermia treatment.

Hyperthermia is one of the most recents therapies for cancer treatment using particles with nanometric size and appropriate magnetic properties for destroying cancer cells. Magnetic nanoparticles (MNP's) of Fe-Ga and synthesized using a polycondensation reaction by sol-gel method were obtained. MNP's of Fe(1.4)Ga(1.6)O(4) that possess an inverse spinel structure were identified by X-Ray Diffraction, Transmission Electron Microscopy, Scanning Electron Microscopy and Energy Dispersive Spectroscopy. The results showed that the MNP's are composed only by Fe, Ga and O and their size is between 15 and 20 nm. The magnetic properties measured by Vibration Sample Magnetometry demonstrated a saturation magnetization value of 37.5 emu/g. To induce the MNP's bioactivity, a biomimetic method was used which consisted in the immersion of MNP's in a Simulated Body Fluid (SBF) for different periods of time (7, 14 and 21 d) along with a wollastonite disk. The formation of a bioactive layer, which closely resembles that formed on the existing bioactive systems and with a Ca/P atomic ratio within a range of 1.37-1.73 was observed on the MNP's. Cytotoxicity of MNP's was evaluated by in vitro hemolysis testing using human red blood cells at concentrations between 0.25 and 6.0 mg/mL. It was found that the MNP's were not cytotoxic at none of the concentrations used. The results indicate that Fe-Ga MNP's are potential materials for cancer treatment of both hard and soft tissue by hyperthermia and drug carriers, among other applications.

Study on the efficiency of nanosized magnetite and mixed ferrites in magnetic hyperthermia.

Magnetic materials, which have the potential for application in heating therapy by hyperthermia, were prepared. This alternative treatment is used to eliminate cancer cells. Magnetite, magnesium-calcium ferrites and manganese-calcium ferrites were synthesized by sol-gel method followed by heat treatment at different temperatures for 30 min in air. Materials with superparamagnetic behavior and nanometric sizes were obtained in all the cases. Thus, these nanopowders may be suitable for their use in human tissue. The average sizes were 14 nm for magnetite, 10 nm for both Mg(0.4)Ca(0.6)Fe(2)O(4) and Mg(0.6)Ca(0.4)Fe(2)O(4) and 11 nm for Mn(0.2)Ca(0.8)Fe(2)O(4). Taking into account that the Mg(0.4)Ca(0.6)Fe(2)O(4) and Mg(0.6)Ca(0.4)Fe(2)O(4) treated at 350 °C showed the lower coercivity values, these nanoparticles were selected for heating tests and cell viability. Heating curves of Mg(0.4)Ca(0.6)Fe(2)O(4) subjected to a magnetic field of 195 kHz and 10 kA/m exhibited a temperature increase up to 45 °C in 15 min. A high human osteosarcoma cell viability of 90-99.5% was displayed. The human osteosarcoma cell with magnesium-calcium ferrites exposed to a magnetic field revealed a death cell higher than 80% in all the cases.