Hydroxy-carbonate apatite: Synthesis, blood compatibility and adsorption of specific pathogenic proteins

Hydroxy-carbonate apatite (CAp) compositions containing carbonate ions from 0 to 10.9 wt% were synthesized by a wet chemical method. Infrared analysis revealed that carbonate ions were substituted both PO₄^3- and OH^- sites. The introduction of CO₃^2- ion into the hydroxyapatite lattice led to an increase in specific surface area and surface charge density. Blood clotting properties were not affected by the contact with CAp samples. The adsorption behavior of proteins was investigated by contacting CAp with model saline containing bovine serum albumin (BSA) and β₂-microglobulin (β₂-MG). The selectivity against β₂-MG increased with increase in the amount of carbonate ions. As surface charge density increased with increase in the amount of carbonate ions, surface charge density played an important role in selective adsorption of β₂-MG, but not a sole factor.