Apatite-formation on silk fiber in a solution mimicking body fluid

Apatite-organic polymer hybrid is expected as a novel material for bone repair. A biomimetic process has focused attention on fabricating such hybrids, where bone-like apatite is deposited on an organic polymer surface in solutions mimicking physiological conditions. In this process, organic polymer substrates can be coated with bone-like apatite layer by soaking in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human extracellular fluid or more concentrated fluids at ambient conditions. To achieve a successful fabrication on such a hybrid, organic substrates should have effective site for nucleation of bone-like apatite on their surfaces. In this study, we examined apatite-forming ability of silk fiber in 1.5SBF which has ion concentrations 1.5 times those of SBF. Apatite formation was observed on raw silk fiber and accelerated by a prior treatment with CaCl2 solution. It is concluded that sericin has a potential on induction of apatite nucleation in the solutions mimicking body environment.