Adsorption of bovine serum albumin on poorly crystalline apatite: influence of maturation

The surface reactivity of synthetic poorly crystalline apatites, similar to bone mineral, is reported in this study. Considerable changes of crystallinity and chemical composition of the solids occurred with time. The maturation process was expressed as a gradual evolution of the initial precipitate toward a highly crystalline apatitic phase, a relocation of nonapatitic phosphate groups accompanied by an increase of apatitic phosphate and the incorporation of hydroxyl ions in the lattice. The adsorption isotherms obtained for the samples investigated in KCl solutions are Langmuirian. The interaction of bovine serum albumin molecules with the solid was related to the structure, the short-range order, and the composition of the crystals. The evolution of the adsorption parameters with the content of labile phosphate groups indicates that these surface species play a leading role in the adsorption process and could consequently affect their biological functions.