High porosity hydroxyapatite foam scaffolds for bone substitute

Very high porosity (>90%) reticulated hydroxyapatite foams were prepared using a flexible, low silica polyurethane foaming system as the organic vehicle. The powder was dispersed in both components of the foam which were then mixed and cast. The ceramic foam was obtained by pyrolysis of the polymer followed by sintering of the powder assembly. Small additions of n-heptane were made to coarsen the foam. Cell diameters in excess of 0.5 mm and windows above 100 mum were obtained in a reticulated structure with porosity of 92%. This scaffold was treated for 48 hours in a culture medium with incubated human osteoblast-like cells, which formed a dense population on the surfaces of the foam.