抄録
So-called bioactive ceramics have attractive features such as direct bone-bonding in living body. They are clinically utilized as important bone substitutes. However, their Young's modulus is much higher than that of natural bone. Previous studies reported that the essential condition for materials to show bone-bonding property, i.e. bioactivity, is formation of bone-like apatite on their surfaces after exposure to the body fluid. The same type of apatite formation can be observed even in a simulated body fluid (SBF) with inorganic ion concentrations similar to those of human extracellular fluid. Formation of the surface apatite can be induced both by dissolution of calcium ion (Ca2+) and by silanol (Si-OH) group formed on the surfaces of materials. On the basis of these findings, organic modification of these components would produce bioactive materials with high flexibility. In the present study, we synthesized organic-inorganic hybrids from starch by chemical modification using glycidoxypropyltrimethoxysilane (GPS) and calcium chloride (CaCl2). Acceptance of the apatite formation of the hybrids was examined in SBF. The hybrids formed apatite in SBF within 7 d, even if molar ratio of CaCl2 to GPS was reduced up to 0.01.
