Porous hydroxyapatite-bioactive glass hybrid scaffolds fabricated via ceramic honeycomb extrusion

The successful fabrication of hydroxyapatite-bioactive glass scaffolds using honeycomb extrusion is presented herein. Hydroxyapatite was combined with either 10 wt% stoichiometric Bioglass((R)) (BG1), calcium-excess Bioglass((R)) (BG2) or canasite (CAN). For all composite materials, glass-induced partial phase transformation of the HA into the mechanically weaker -tricalcium phosphate (TCP) occurred but XRD data demonstrated that BG2 exhibited a lower volume fraction of TCP than BG1. Consequently, the maximum compressive strength observed for BG1 and BG2 were 30.3 +/- 3.9 and 56.7 +/- 6.9MPa, respectively, for specimens sintered at 1300 degrees C. CAN scaffolds, in contrast, collapsed when handled when sintered below 1300 degrees C, and thus failed. The microstructure illustrated a morphology similar to that of BG1 sintered at 1200 degrees C, and hence a comparable compressive strength (11.4 +/- 3.1MPa). The results highlight the great potential offered by honeycomb extrusion for fabricating high-strength porous scaffolds. The compressive strengths exceed that of commercial scaffolds, and biological tests revealed an increase in cell viability over 7days for all hybrid scaffolds. Thus it is expected that the incorporation of 10 wt% bioactive glass will provide the added advantage of enhanced bioactivity in concert with improved mechanical stability.