Abstract
Hydroxycarbonate apatite (HCA) coatings on two types of composites containing calcium carbonates were prepared by a biomimetic method using simulated body fluid (SBF). Poly(lactic acid) (PLA) composites containing calcium carbonates formed HCA on the surface after soaking in SBF for 3 h. The PLA composites had numerous carboxy groups bonded with Ca2+ ions. Titania composites containing calcium carbonates formed HCA on the surface after soaking in SBF for 1 d. Formation of titanium hydroxide groups was drastically promoted on the titania composite by soaking in SBF. The HCA-forming ability of these composites was much higher than that of PLA or titania crystals. Vaterite in the composites plays an important role in HCA formation in SBF. By soaking in SBF, a large amount of Ca2+ ions released from the vaterite increase in the supersaturation of HCA in SBF.
