Influence of Carboxyl Groups Present in the Mineralising Medium in the Biomimetic Precipitation of Apatite on Collagen

Calcium phosphate was precipitated by biomimetic method on collagen fibrils from conventional and revised simulated body fluid (C and R SBF) solutions in presence of bovine serum albumin (BSA) and polyacrylic acid (PAAc). The precipitates formed on the collagen fibrils were analyzed using SEM, TF-XRD and FT-IR. Partial modification in the morphology of the precipitates was observed. An increase in concentration of BSA and PAAc in the SBF solution reduced the crystallinity of the precipitates. The precipitates formed were B-type carbonate apatite. Presence of chelation complex of Ca and carboxyl groups was also identified. Introduction Mineralized tissues such as bone and teeth are biologically produced composites of collagen and hydroxyapatite (HAP). The carboxylate group of collagen is one of the key factors for the nucleation of HAP (1). The non-collagenous proteins present in the body fluids was found to play potential roles in the mineralization process in vivo (2). Also compounds containing COOH groups are known to be effective in the formation of apatite in the body environment. In this study in vitro investigation of the effect of BSA and PAAc [having carboxyl moieties] dissolved in the mineralizing solution (SBF) in the formation of apatite on collagen fibrils was carried out.