Microstructure and Mechanical Properties of Hydroxyapatite Nanofibers Synthesized Through the Microwave-Assisted Hydrothermal Method for Biomedical Applications

Abstract

Hydroxyapatite (HAp) is the main mineral component of bones and has various applications in the biomedical area. The objective of this work was first to synthesize and characterize hydroxyapatite nanofibers with a crystalline growth orientation and with a Ca/P ratio similar to bone and secondly to elaborate composite materials with HAp nanofibers that possess mechanical properties similar to trabecular human bone. For this, we synthesized HAp nanofibers by microwave-assisted hydrothermal technique and performed the structural characterization by means of the X-ray powder diffraction method. The morphological, topological, and microstructural characterization was performed with scanning electron microscopy and high-resolution electron microscopy. With HAp as a base, 3 types of porous ceramic materials were obtained using the modified gel casting method. Finally, these composite materials were subjected to mechanical compression tests. Given the results, synthetic HAp nanofibers exhibited a hexagonal morphology, a preferential crystal orientation in the [300] direction, and a purity level of [001]. In addition, a Ca/P ratio similar to that of human bone was obtained. In the mechanical tests, the HAp composite materials got maximum compressive stress of 20 MPa, which corresponds to that required by trabecular bone. In conclusion, the composite material obtained has physicochemical, structural, morphological, and mechanical properties similar to those of natural bone tissue, so it is possible to consider the use of this type of material as a bone replacement.