Preparation and comparison of natural and synthetic hydroxyapatite scaffolds made by cold isostatic pressing method

Due to its bioactivity and biocompatibility properties,hydroxyapatite (HA) with Ca10(PO4)6OH2 chemical formula has been broadly employed for bone and teeth treatment applications as hard tissue. In the present research, hydroxyapatite was synthesizedvia sol-gel and natural (extraction from bovine cortical bone) methods. Natural hydroxyapatite had an average particle size of about 5 μm and synthetic hydroxyapatite powders wereless than100 nm. Therefore, synthetic hydroxyapatite powders size was smaller than natural hydroxyapatite powders. Scaffolds were prepared by cold isostatic pressing method (CIP) and sintered at 1300°C. In order to evaluate the characteristics of the produced hydroxyapatite and morphological investigation, X-ray diffraction (XRD) and Fourier Transform infra-red spectroscopy (FTIR) were performed on the samples. Scanning electron microcopy (SEM) and Atomic force microscopy (AFM) were carried out to investigate the particle size, size and morphology of porosities and to study thetopography of surfaces. The results of scanning electron microscopy were in agreement with the AFM topography.After measuring the density of scaffolds, the compression tests were carried out on standard samples. Accordingly, the compression strength and density of samples from synthetic hydroxy apatite were more than those of the samples produced from natural hydroxyapatite. The compression strength of synthetic hydroxyapatite scaffold was 55.6 MPa and its density was 2.97 g/cm3. Cell culture was done on hydroxyapatite scaffolds with human osteoblast stem cells after14 days. Results showed that cell proliferation on natural hydroxyapatite scaffolds were less than synthetic hydroxyapatite scaffolds.