Development of Custom-Built Bone Scaffolds Using Mesenchymal Stem Cells and Apatite-Wollastonite Glass-Ceramics

There is a clinical need for new bone replacement materials that combine long implant life with complete integration and appropriate mechanical properties. We have used human mesenchymal stem cells (MSCs) to populate porous apatite-wollastonite (A-W) glass-ceramic scaffolds produced by the layer manufacturing technique, selective laser sintering, to create custom-built bone replacements. Confocal and scanning electron microscopy were used to determine optimal seeding densities and to demonstrate that MSCs adhered and retained viability on the surface of A-W scaffolds over a culture period of 21 days. We found a significant increase in the number of MSCs growing on the scaffolds over 7 days. Using bromodeoxyuridine incorporation we demonstrated that MSCs proliferated on the scaffolds. Using real-time PCR we analyzed the expression of the osteogenic markers alkaline phosphatase, collagen type-I, Cbfa-1, osteocalcin, osteonectin, and osteopontin by MSCs cultured in the absence of osteogenic supplements. The expression of the osteogenic markers by MSCs was equivalent to or significantly greater on A-W scaffolds than on tissue culture plastic. We also identified significantly higher alkaline phosphatase activity on A-W compared to a commercial calcium phosphate scaffold. These results indicate for the first time the biocompatibility and osteo-supportive capacity of A-W scaffolds and their potential as patient-specific bone replacement materials.