Effects of compressive ratio and sintering temperature on mechanical properties of biocompatible collagen/hydroxyapatite composite scaffolds fabricated for bone tissue engineering

A sponge template method was used to synthesize scaffolds from hydroxyapatite (HAp) using varying sintering temperatures and compressive ratios. The HAp scaffolds were fabricated with collagen (COL) or collagen/HAp particles under room temperature coating conditions. The microstructure and mechanical properties of the fabricated biomaterials were analyzed by FE-SEM and EZ Test, respectively. The FE-SEM micrographs showed microporous structure of the fabricated composite scaffolds. Incorporation of COL or COL/HAp into pure HAp scaffolds under coating conditions significantly reduced the porosity and enhanced the mechanical properties. The results demonstrated that the porosity of fabricated scaffolds was reduced by lowering the compressive pressure and increasing the sintering temperature. The maximum estimated compressive moduli at 1000, 1100 and 1200 °C for HAp-COL and HAp-COL/HAp composite scaffolds were 4.36, 2.93, 5.09 MPa and 4.57, 8.19, 5.02 MPa, respectively, at a 50% compressive ratio. It was assumed that porosity was effectively reduced to the maximum level at a 50% compressive ratio. An in vitro stem cell study showed significant cell adhesion and proliferation over the fabricated HAp-COL and HAp-COL/HAp composite scaffolds. These results confirmed that fabrication of pure HAp with COL and COL/HAp materials had advanced effects on the mechanical properties of fabricated porous composite scaffolds.