Abstract
We prepared the novel composites consisting of calcium carbonates and polylactic acid (PLA) and examined the apatite-forming ability in simulated body fluid (SBF). It is well known that calcium carbonate has three polymorphs, viz., calcite, aragonite and vaterite. The composites containing aragonite or vaterite formed bonelike apatite particles on the surface after soaking in SBF for 1 w or 3 h, respectively. No apatite forms on the composite consisting of calcite and PLA even after 1 m of soaking in SBF. From these results, the composites containing vaterite have much higher apatite-forming ability than the other composites containing calcite and aragonite. The rapid apatite formation on the composites containing vaterite was suggested to originate from the integration of PLA having carboxy groups bonded with calcium ions for the apatite nucleation and vaterite having an ability to effectively increase the supersaturation of the apatite.
