Microscopy and microanalysis techniques have played an important role in our understanding of how biomaterials interact with their environment. In first part of this study, we will focus on the behavior of bioactive glass, whereas in the second a model surface will be investigated. Upon implantation bioactive glass undergoes a series of reactions that leads to the formation of a calcium phosphate-rich layer. Most in vitro studies of the changes that occur on the surface of bioactive glass have employed the use of buffer solutions with compositions reflecting the ionic composition of interstitial fluid. Although these studies have documented the physical and chemical changes associated with bioactive glass immersed in aqueous media, they do not reveal the effect of serum proteins and cells which are present at the implantation site. In the present study, we document, using atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS), significant differences in reaction layer composition, thickness, morphology and kinetics of formation arising from the presence of serum proteins.