The effect of temperature on isolation and characterization of hydroxyapatite (HAp) from tuna bone was evaluated at different temperatures ranging from 200 °C to 1200 °C. The calcined bones were characterized by thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and cytotoxicity assay. The FTIR and TGA results revealed the presence of inorganic and organic matrices in raw bone and a preserved carbonated group in the derived HAp. The XRD results of the derived HAp were coherent with the Joint Committee on Powder Diffraction Standards (JCPDS-09-0432/1996) data. In addition, FE-SEM results revealed the formation of nanostructured HAp (80-300 nm) at 600 °C and crystal agglomeration was observed with an increase in temperature. The calcium to phosphorous weight ratio was determined by EDX results of treated bones. Derived HAp with various crystal sizes had no cytotoxicity on the MG 63 cell line. Based on the analysis, we conclude that varying the isolation temperature between 600-900 °C has tremendous impact on the production of HAp from Thunnus obesus with required properties.
Keywords: Thunnus obesus; X-ray diffraction; cytotoxicity; hydroxyapatite; thermal calcinations.