Water Structure and Polymer Dynamics in Hydrated Blood Compatible Polymers

Biomaterials with good blood compatibility are essential for new medical devices and/or therapies. Thus, there are many attempts to improve their performance for blood. To this end, biomaterials with a variety of surfaces have been proposed and some of them are already in clinical use. These surfaces can be classified into four groups; 1) super-hydrophilic surface, 2) micro-phase-separated domain surface, 3) biomembrane like surface and 4) bioactive-molecules incorporating surface. It is not clear, however, how these surfaces exhibit good blood compatibility except the case of 4). Recently, we found that poly (2-methoxyethyl acrylate) (PMEA), which does not belong to any of the classes mentioned above, exhibits excellent blood compatibility, but the mechanism of its good performance has not yet been fully understood. In order to gain an insight into its good performance, we have investigated the water structure in PMEA, and also polymer dynamics by solid-state NMR. Here, we discuss the role of water structure and polymer dynamics in determining good-compatibility of biomaterials from the viewpoint of water structure on the basis of various reports about the water structure in polymers investigated by DSC, FT-IR and NMR.