Fabrication of Nano-Size AB-Type Carbonated Hydroxyapatite Particles from Seashells

Hydroxyapatite (HA) is a commonly used biomaterial for bone grafting. Unfortunately, the lack of carbonate ions in normal HA limits its osseointegration ability. Alternatively, carbonate-substituted hydroxyapatite (CHA) was reported to be a better bone substitution because it has almost the same chemical composition and structure as natural bone minerals. In this study, a novel method was proposed to directly synthesize CHA through one-step hydrothermal exchange from seashells. The morphology and the amount of carbonate-substitution of the fabricated CHA can be well controlled by adjusting the PH during the reaction: with the increasing of PH, the morphology of the final product was transferred from long needle-like to sheet-like and the amount of CO32 substitution increased gradually. The bioactivity of the products was evaluated by CKK-8 assay. It was found that the CHA significantly improved bioactivity compared to the control group, and the needle-like CHA had a better bioactivity than that of the sheet-like CHA.