Apatite Deposition on Silk Sericin in a Solution Mimicking Extracellular Fluid: Effects of Fabrication Process of Sericin Film

An apatite-organic polymer hybrid is expected as a novel material for medical application, because it shows high biological affinity and high flexibility. In order to fabricate this type of hybrid, a biomimetic process was proposed, in which a bone-like apatite layer can be coated onto organic substrates by using a simulated body fluid (SBF) at ambient conditions. Potential of induction of heterogeneous nucleation of apatite on substrate materials is an important parameter to achieve a successful coating of apatite. Recently, it was reported that sericin, a protein existing on the surface of raw silk fiber, showed apatite-forming ability in 1.5 SBF which has 1.5 times the ion concentrations of SBF. In the present study, the structural effect of sericin on its apatite-forming ability was investigated in 1.5SBF. Apatite was deposited on sericin with high molecular weight and β-sheet structure in 1.5SBF after 7 days.