IN VIVO BIOCOMPATIBILITY OF APATITE-FIBER SCAFFOLD WITH ENHANCED MECHANICAL PROPERTY USING PIG MODEL BY IMPLANTING INTO TIBIA

We have successfully synthesized single-crystal apatite fibers (AF) by a homogeneous precipitation method with urea. The AF has a higher solubility than isotropic HAp powders. Thus, using the AF, we developed apatite-fiber scaffolds (AFSs) that enables three-dimensionally cell culture and induces differentiation into osteoblasts. Recently, we have successfully enhanced mechanical properties of the AFSs using carbon beads (CB) with a diameter of 150 m and 20 m, together with uniaxial pressing of the green compacts. In this study, we fabricated the AFSs with enhanced mechanical property (AFS700(50-50)), and then implanted them into tibia of pig to evaluate a biocompatibility to a hard tissue. The porosity of the resulting and compressive strength of typical AFS700(50-50) were 93.5% and 128 kPa, respectively. The AFS700(50-50) had a number of micro pores, macro-pores and interconnected pores. In the histological observation after 13 weeks implantation, newly-formed bone and cells were invaded into pores of the AFS700(50-50), and the scaffolds were incorporated into a cycle of bone remodeling. The AFS700(50-50) was also observed to be replaced with autologous tissue. The present scaffold may be expected as a high performance scaffold for bone regeneration. (Received May 8, 2012; Accepted May 16, 2012)