Development of a synthetic trabecular bone graft utilizing a two phase glass-ceramic

The aim of this work was to produce and characterise porous glass-ceramic scaffolds that mimicked human trabecular bone through the foam replica technique. Parent glasses were formed via a melt quench route to produce glass frits, these were then processed into powders consisting of <45 µm particles confirmed through particle analysis. DSC analysis confirmed a glass transition region of ~ 750 °C, two crystallisation peaks were noted at 886 °C and 942 °C. Combining multiple glass batches exhibited properties consistent with single batch analysis, allowing for scale up of glass volumes and sample sizes for characterisation. Slurries of varying ratios of glass and binder (polyvinyl alcohol) were then produced and used to coat a polyurethane foam template. Two distinct heat treatments were then designed from initial studies; SEM analysis confirmed a dwell at 800 °C for 5 hours sufficiently sintered the glass particles, XRD analysis confirmed a tertiary dwell at 950 °C for 1 hour formed both apatite and wollastonite phases.
Biaxial flexural testing and micro-CT analysis showed that with decreasing glass content within the initial slurry the resultant mechanical and architectural properties diminished. Excessive use of binder within the initial slurry was also found to diminish the consistency and properties of the scaffolds produced. Coating the porous scaffolds with fluorapatite was shown to be feasible; the crystallinity of the substrate was found to alter the resultant crystal morphologies. Human adipose derived stem cells (hADSC’s) were shown to both attach and proliferate on scaffolds, with or without a fluorapatite coating.