Surface modifications of plasma-sprayed bioglasses upon interaction with phosphate buffer and albumin solutions: a photoelectron spectroscopy study

X-ray photoelectron spectroscopy (XPS) was used to define the chemical comp osition of the outermost surface layer and the surface modification of a pl asma-coated phospho-silicate glass (identified as BVA) when immersed in pot assium phosphate buffer or in phosphate-buffered human albumin solution. It s behaviour was compared with that of a soda-lime-based glass (identified a s BVH) treated in the same way. The surface percentage composition of plasm a-sprayed glass was consistent with the bulk composition. After incubation with buffer, a Ca-P-rich layer developed only on the surface of BVA glass. Human serum albumin was bound reversibly to both glasses; however, the prot ein completely covered the BVA glass surface within 24 h, with the formatio n of a mixed albumin-Ca-P layer, whereas 4 days of incubation were necessar y for complete coverage of the BVH glass surface. The thickness of the orga nic/inorganic overlayer has also been estimated, Copyright (C) 2000 John Wi ley & Sons, Ltd.