Preparation of a hemiporous hydroxyapatite scaffold and evaluation as a cell-mediated bone substitute

A hemiporous hydroxyapatite (HAp) scaffold was prepared to support the tissue engineered approach to the restoration of damaged bone. The scaffold comprised a porous cell-seeded part and a non-porous load bearing part. A wet processing technique of HAp suspensions was used to shape the hemiporous body. The structure of the porous part was tailored using a stack of heat treated porogen placed on the plaster. The prepared specimen had approximately 30 layers of connected pores, which could accommodate sufficient human bone marrow stromal cells (hBMSCs). The result of an in vitro test showed that hBMSCs successfully proliferated and produced extracellular matrices even at the pore in the deep portion of the scaffolds. The in vivo test in the distal femur of a rabbit showed the formation of new fibrous tissue and tubular vessels with red blood cells in the hBMSCs-seeded scaffold from the pores at the deepest portion as well as from the pore at the periphery of the scaffold. The result was in distinct contrast with the scaffold without cell loading. The preloading of cell was thus very effective in the migration of cells in spite of the unconfirmed connectivity among pores. The present casting approach had the merits of simplicity and versatility in tailoring the scaffold structure without an elaborate device.