ABSTRACT
I. INTRODUCTION Biomaterial* scientists have long sought a single, material-related parameter that effectively measures biocompatibility and might serve as a practical design guide. It was quite natural that these investigators looked to theories of surface energetics and wetting for such parameters since surface properties are important determinants of biomaterials function. As examples, Baier pioneered the use of Zisman's critical surface tension as an indicator of blood compatibility [1-4] and bioadhesion [5-8]. Neumann and co-workers employed their "equation-of-state" approach to calculate interfacial tensions from contact-angle measurements [9-12] that, in turn, were used to predict cell adhesion [13-20] and thromboresistance [21,22]. Whereas concepts such as these have served as useful general guidelines or "rules of thumb" for biomaterials design, each has fallen far short of being the desired quantitative predictor of biocompatibility, particularly when applied to proteinaceous environments. Thus, the detailed physicochemical events that link surface chemistry and interfacial properties with the biological response to materials remain obscure.
