Surface modification of calcium–copper hydroxyapatites using polyaspartic acid

Mixed calcium–copper hydroxyapatite (Ca–CuHAp), with general formula Ca(10−x)Cux(PO4)6(OH)2, where 0 ≤ x ≤ 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-l-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca–CuHAp–PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (Psingle bondOH) band of (HPO4)2− groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.