Towards bone replacement materials from calcium phosphates via rapid prototyping and ceramic gelcasting

Biomimetic porous scaffolds made of calcium phosphate mineral are promising structures to develop bone replacement materials. In order to fabricate scaffolds with a strut size of 450 μm, we used a stereolithographic technique which selectively polymerises photosensitive liquid resin by visible light to produce casting moulds for ceramic gelcasting. These moulds were filled with a water based thermosetting ceramic slurry which solidifies inside the mould. After burning the resin mould and sintering, hydroxylapatite structures with designed, fully interconnected macroporosity were obtained. eosteoblastic cell line MC3T3-E1, derived from mouse calvariae, was used to test for biocompatibility in cell culture experiments. The cells were seeded on the scaffolds immersed in the culture medium and cultured for 2 weeks. Thereafter the cells on the scaffold were fixed and investigated by histological methods. The osteoblast-like cells were found to cover the whole external and internal surface of the scaffold, they were embedded in collagenous extracellular matrix. The cells had in particular the tendency to fill any crack or opening and to generally smooth the exposed surfaces.