抄録
Bone is a kind of composite material with the smart microscopic structure mainly composed of collagen fibers and hydroxyapatite crystals. Recently, bioabsorbable composite materials, such as collagen/hydroxyapatite composite materials and hydroxyapatite/poly-L-lactic acid composite materials, had been investigated and developed as substitute and scaffold materials for the bone regeneration. Here, it is expected to complete the bone regeneration by transplanting artificially produced bone tissue itself into bone defects. In this study, we aim to develop the bottom-up-type designing method of optimized microscopic structures of collagen/hydroxyapatite for the artificial bone tissue materials. In this study, we developed an evaluation method of microscopic mechanical properties of collagen fibers, and evaluated the effect of concentration of bridging agent (1-ethyl-3-carbodiimide hydrochloride: EDC) on the tensile strength of prepared collagen fibers. As results, we successfully developed a micro-tensile-testing device using a micrometer head, a rack-and-pinion stage, a z-direction lifting stage, an acrylic plate and a stainless base. The tensile strength of collagen fibers with EDC concentration of 10 mmol/L was about 2 times higher than that without EDC. Within the range of EDC concentration of 10-50 mmol/L, the tensile strength of prepared collagen fibers decreased with increasing EDC concentration. It was suggested that the EDC concentration, where the fibrosis and bridging can proceed simultaneously, could optimize the mechanical properties of collagen fibers.
