Introduction of Alkylammonium into Calcium Silicate Hydrate Towards Application in Development of Novel Biomaterial

Abstract

Human body contains trace inorganic elements that play important roles in the regulation of vital reactions. Biomaterials releasing the trace inorganic elements are suggested to be beneficial for tissue reconstruction remedies. The authors focused on inorganic layered compounds that give drug-releasing system tailored by assembling nanosheet-like crystals of the compounds with inserting ions and macromolecules which promote tissue regeneration. In the present study, calcium silicate hydrate (C-S-H) was selected as the framework, and its preparation conditions via precipitation method were explored. Moreover, the incorporation behaviors of alkylammonium molecules into the C-S-H were evaluated by their simultaneous addition during the method. Agglomerates of nanosheet-like C-S-H were precipitated by introducing calcium nitrate aqueous solution into equimolar concentration of sodium silicate aqueous solution in a controlled manner. By soaking C-S-H into simulated body fluid, which mimicked the inorganic elemental composition of human blood plasma, bone-like apatite was precipitated on its surface. The incorporation of tetrabuthylammonium cations (TBA⁺) were conducted by the addition of its hydroxide into sodium silicate aqueous solution during the preparation. XRD pattern of the sample showed the broadening of a peak, attributed to the interlayer distances in a C-S-H crystal. These results suggested the introduction of TBA⁺ in the C-S-H.