Fabrication and Characterisation of Gelatine/Hydroxyapatite Porous Scaffold

Abstract

Hydroxyapatite (HAp) has been used as bone substitute materials due to its bone compatibility after implantation. However, major drawbacks of HAp typical of ceramic materials are its brittleness which limits its applications. Therefore, to introduce toughness in HAp scaffold, gelatine layer was coated on the surface of the HAp scaffold. In this research, porous HAp scaffolds coated with gelatine are fabricated via polymer reticulate method using polyurethane foam (PU) template. Initially, HAp powders were calcined at 1100°C to reduce its viscosity and agglomeration effect when formed into slurry. Preparation of HAp slurry with 40wt% of calcined HAp powders and 3 wt% of polyvinyl alcohol (PVA) powder were prepared before immersing the PU foams. The HAp coated PU foams were then heat treated at 650°C for an hour to burnout all PU, then sintering was done at 1100°C. Finally, the sintered HAp scaffold was coated with 10, 15 and 20wt% of gelatine. Additionally, the gelatine was crosslinked at 130°C and 160°C. Compressive strength analysis shows that as the wt% of gelatine increases the compressive strength of the gelatine/HAp scaffold increases. Highest compressive strength of 71.0 kPa was obtained for 20wt% of gelatine coated on the HAp scaffold. Higher crosslinking temperature also increases the compressive strength. The average compressive strength for gelatine/HAp scaffold crosslinked at 130 °C and 160 °C are 66.4 kPa and 72.3 kPa respectively. XRD analysis shows that 66% of HAp transformed into beta-tricalcium phosphate (β-TCP) after calcination while 71% transformed into β-TCP after sintering. FTIR and EDX analysis showed that the higher amount of gelatine content found in scaffolds with higher crosslinking temperature correlate to the increased in compressive strength. SEM analysis shows that the increased in the compressive strength is attributed to the covering of cracks on the strut of the HAp scaffolds by the gelatine.