Evaluation of Bone Regeneration Potential of Long-Term Soaked Natural Hydroxyapatite

Natural hydroxyapatite (HA) was derived from pig bones (PBs) for tissue engineering applications through heat treatment. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDX), and field emission scanning electron microscopy (FE-SEM) were employed for the analysis of heat-treated PB powder. In addition, inductively coupled plasma (ICP) mass spectroscopy was applied to examine the phase organizations and chemical composition of PB powder. The Ca/P ratio in bone powder was between 1.5 and 1.6. Moreover, in vitro and in vivo studies were performed to assess the biocompatibility of long-term soaked bone powder. These results can be used to (i) establish chemical characterization by analyzing SEM microstructures and undertaking XRD, XRF, EDX, FTIR, and ICP atomic emission spectrometry; (ii) perform cytotoxicity evaluations using human mesenchymal stem cells; and (iii) conduct assessments using an in vivo animal model and histological observations. No significant changes in chemical composition were observed in long-term soaked samples with respect to the original HA. Cells properly adhered to the surface of soaked samples, and rapid hilling of the defected skull was observed in the presence of the soaked sample, indicating its potential for use as a tissue engineering biomaterial. These results suggested that heat treatment at 1200 °C could produce natural bioceramics based on calcium phosphate, which retained their osteogenic potential after 36 months of soaking.