Hydroxyapatite Scaffold Manufacturing under the Space Holder Method: Analysis of Physical Properties and Biocompatibility

Abstract

The space holder method was applied to the manufacture of hydroxyapatite (HA) scaffolds by a pressureless sintering process. The aim is to develop the stages of making scaffold using the space holder method and to prove the readiness of the scaffold, especially from its physical properties and biocompatibility. The novelty of this work is the stages of processing scaffold materials in the form of slurries to produce green body scaffolds. Micron- and nano-sized HA powders were mixed in the form of slurry with polyvinyl alcohol (PVA) and ethanol. The PVA-containing HA was added with polymethyl methacrylate (PMMA) to have ratios ranging from 90:10 wt% to 65:35 wt%. The green bodies were prepared by uniaxial pressing at 200 MPa. The sintering was carried out by preheating at temperature of 700°C with a holding time of 1 h. The temperature was then increased to 1200°C with holding time of 3 h (heating rates were maintained at 5°C/min). The HA scaffolds were characterized by observing the phase, microstructures, and macrostructures; measuring the pores, testing their porosity and compressive strength. The biocompatibility properties were analyzed by testing for direct toxicity. The results indicated that the HA scaffolds made in this study met the standards since the compressive strength value was 2.23 MPa with 65.64% porosity and 126 μm to 385 μm pores size. SEM image showed the interconnection between the pores, the HA scaffolds made were non-toxic. The resulting scaffold has a great potential for further testing in living organisms.