Preparation of Calcium Carbonate Composites and Their Apatite-Forming Ability in Simulated Body Fluid

Abstract

This paper presents the preparation of the novel composites consisting of calcium carbonates and poly(L-lactic acid) (PLLA) and their apatite-forming ability in simulated body fluid (SBF). It is well known that calcium carbonate has three polymorphs, i.e., calcite, aragonite and vaterite. On the PLLA composites containing aragonite or vaterite, bone-like apatite particles formed on the surface after soaking in SBF for 7 days or 3 hours, respectively, while no apatite formed on the composite consisting of calcite and PLLA even after 30 days of soaking in SBF. The composites containing vaterite have much higher apatite-forming ability than the other composites containing calcite or aragonite without vaterite. The rapid apatite formation on the composites containing vaterite was suggested to originate from the integration of PLLA having carboxy groups bonded with calcium ions for the apatite nucleation and vaterite having an ability to effectively increase the supersaturation of the apatite.