When an artificial material surface is exposed to blood, plasma proteins coat the surface before cellular blood components can interact with it. The hierarchy of events: surface ---> protein layer ---> platelet and cell adhesion ---> a trigger for a foreign body reaction, suggests a causal relationship between the effects of surface properties, interfacial protein and cell attachment dynamics and the signal for the host organism to biologically isolate the artificial material. In this competing continuation application we propose to improve, develop and use several new scanning probe microscopies as in situ , high resolution research tools for investigating the two-dimensional variation of biomaterial surface property, like surface elasticity and surface energy, and related spatial distribution of surface adhered plasma proteins, including their orientation and conformation. In particular, we propose the continuation of the present research activities for another four years with the following specific research goals: l) Completion of development of constant compliance SFM force modulation method and its use in characterizing microphase-separated biomaterial and model heterogeneous surfaces in terms of the two-dimensional variation of their surface elasticity and surface energy. Application of the technique to map these two properties of biomaterial surfaces, with and without adhered proteins, under quasi-physiological conditions. 2) Study of the two-dimensional distribution of plasma proteins adhered to model and biomaterials film surfaces in aqueous environment by non-contact near-field and far-field scanning fluorescence microscopy and by a scanning specific adhesion force microscopy. Simultaneous detection of surface distribution of two or more proteins using two or more different fluorescence labels. Examine the possibility of a single surface-bound protein molecule spectroscopy. 3) Evaluate the combined information about the surface heterogeneity and plasma protein distribution at biomaterial interfaces. Build a spatial and temporal picture of plasma proteins at biomaterial interfaces which ranges from the two-dimensional map of biomaterial surface property to the spatial distribution of individual plasma proteins, all at high resolution and in a quasi-physiological environment.
