Nanostructurated materials for hyperthermia treatment of bone tumors

Sol-gel method has been used for obtaining polycrystalline iron containing hydroxyapatite materials usable for hyperthermia. In calcium phosphate sol-gel glasses with Ca/P ratio of 1.67, like that in hydroxyapatite, the bone mineral phase was introduced up to 5 mol% Fe2O3. X-ray diffraction (XRD) analysis evidenced the growth of hydroxyapatite type crystals in the heat treated samples. As was revealed from the width of the main diffraction peak the developed crystals are of nano size after heat treatment at 300 deg deg C. Their size increases with heat treatment time and temperature. After heat treatment at 300 deg C only in the samples with iron content the crystals remain of hydroxyapatite type, showing that the iron plays a stabilising role in this phase. The phosphorus environment was investigated by Nuclear Magnetic Resonance (NMR). The 31P NMR spectra show that the phosphorus structural units in nanostructurated samples are completely different from those of the samples resulted after higher temperature heat treatment. These results are correlated with the XRD data.