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 crystalli nity and chemical composition of the solids occurred with time. The maturat ion process was expressed as a gradual evolution of the initial precipitate toward a highly crystalline apatitic phase, a relocation of nonapatitic ph osphate groups accompanied by an increase of apatitic phosphate and the inc orporation of hydroxyl ions in the lattice. The adsorption isotherms obtain ed for the samples investigated in KCl solutions are Langmuirian. The inter action 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 ads orption process and could consequently affect their biological functions. ( C) 2000 Elsevier Science Ltd.