Abstract
So-called bioactive ceramics exhibit specific biological affinity, i.e. direct bonding to surrounding bone, when implanted in bony defects. However, there is limitation on clinical applications, because of their inappropriate mechanical properties such as low fracture toughness and high elastic modulus. Novel bioactive materials exhibiting high flexibility have been desired. The essential prerequisite for artificial materials to exhibit bioactivity is deposition of bone-like apatite on their surfaces in body environment. This apatite deposition is governed not only by the dissolution of the materials but also by heterogeneous nucleation on the materials surface, followed by crystal growth by consuming calcium and phosphate ions from surrounding body fluid. These findings bring us an idea that bioactive organic-inorganic hybrids with high flexibility can be developed by control in direction and amounts of transformed chemical species. So, the control in chemicovectors on bioactive materials provides attractive design of bone-bonding materials with various functionalities. In this paper, we review development of organic-inorganic hybrids from hydroxyethylmethacrylate (HEMA), starch and collagen-like polypeptide, on the view points of chemicovector.
