Effect of Nano-zirconia on Microstructure and Biological Behavior of Hydroxyapatite-Based Bone Scaffolds

Abstract

In this research study, the effect of zirconia nanoparticles on the biological properties of the hydroxyapatite (HA) scaffolds was evaluated. The zirconia nanoparticles with various weight percentages of 5, 10, and 20 were mixed with hydroxyapatite powder using a ball-milling process. Then, they were cold pressed and heat-treated at 1150 °C. Scanning electron microscope and x-ray diffraction analysis were used to evaluate the morphology and phase analysis of the samples, respectively. The results of the microstructure and phase analysis revealed that some zirconia nanoparticles reacted with the HA during the sintering process, which besides the formation of the tertiary calcium phosphate and calcium zirconium phases, it resulted in creating some microporosities in the scaffold. The biological behavior of the samples was investigated by osteoblast-like cells. The results of the biological assessment demonstrated that the presence of the zirconia nanoparticles in the HA scaffold improved the biological behavior (cell attachment and cell proliferation). The HA specimen composed with 10 wt.% zirconia nanoparticles showed the highest bioactivity. In addition, the compressive strength of the HA sample composed of 10 wt.% zirconia nanoparticles was improved by 30%.