Bone Formation in a Scaffold Composed of Cylindrical Hydroxyapatite and Tryptophan- or Lysine-Coated Sponge in Vivo

Because of the three-dimensional structure of bone or hard tissue such as a tooth, a scaffold is ne-cessary for its regeneration by cellular engineering. Commonly, for in vivo examination, hydrox-yapatite (HA) has been used as such a scaffold. Cylindrical HA with a hollow center, which included a columnar formalin-treated polyvinyl alcohol sponge, was used in this examination as a scaffold. The sponge had been coated with L-tryptophan or L-lysine before insertion into the hollow center of the HA. Rat bone marrow cells (rBMCs) derived from the femur were seeded in the sponge be-fore insertion into the hollow center of HA. The number of rBMCs seeded in each sponge was 1.5 × 106. These scaffolds were implanted subcutaneously into the backs of Fischer 344 rats for 6 weeks. In the amino-acid-coated sponge in HA, osteogenesis was found histologically. An osteocalcin level of approximately 10 µg was measured in the scaffolds with L-tryptophan-coated formalized poly-vinyl alcohol sponge containing rBMCs, 4 µg on average in the scaffolds with L-lysine-coated spong