A comparative study of the mechanical integrity of natural hydroxyapatite scaffolds prepared from two biogenic sources using a low compaction pressure method

Abstract

With a view to enhancing laboratory and application-based pedagogical approaches in bioengineering, a comparison of the physical, chemical and mechanical properties of natural hydroxyapatite produced from non-separated animal bones (NB) and catfish bones (CB) obtained by thermal treatment and a low compaction pressure method has been reported in this study. The structure, morphology and surface chemistry of the processed biomaterials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectroscopy, respectively. Uniaxial compaction using a pressure of 1 MPa was used on circular shaped hydroxyapatite scaffolds to measure the mechanical properties of the produced scaffolds. From XRD analysis, both samples showed prominent reflections of the hydroxyapatite phase, suggesting high crystallinity and phase stability. The morphology of the powders showed irregular shapes with large agglomerates for non-separated animal bones-derived hydroxyapatite as compared to more open pores in the catfish bones-derived hydroxyapatite. Hydroxyapatite produced from catfish bones revealed a microstructure with open pores which is useful in terms of cell adhesion. The hydroxyapatite products revealed Ca/P ratios of 1.58 and 1.63 for catfish bones (CB) and non-separated animal bones-derived hydroxyapatite, respectively. Improvements in the fracture toughness were observed for CB in comparison with NB. Calculated fracture toughness values were 5.72 MPa.m1/2 and 2.35 MPa.m1/2 for catfish bones and non-separated animal bones-derived scaffold respectively. These results are useful in terms of the production and biomedical applications of natural hydroxyapatite.

Keywords

• Sintering
• Mechanical properties
• Apatite
• Bone implants
• Ca/P molar ratio