Surface Modifying Oligomers Used to Functionalize Polymeric Surfaces: Consideration of Blood Contact Applications

The surface modification of existing polymeric biomaterials represents a key strategy for improving the hemocompatibility in long- and short-term biomedical materials without altering their bulk properties. Several techniques have been widely explored to generate surfaces that can prevent the activation of the coagulation system and lead to subsequent clot formation on the surfaces of polymeric blood contacting devices. In particular, strategies whereby the base polymer is blended with surface additives (SMAs) and surface modifying macromolecules (SMMs) are now recognized as practical and effective methods to improve surface polymeric materials. This review highlights the more recent advances in the synthesis of such additives and their blending with base polymers, with a specific focus on SMAs and SMMs with a molecular weight in the oligomeric range (< M-n similar to 12 kDa). The surface characterization of these modified materials is discussed in terms of water contact angle, X-ray photoelectron microscopy, atomic force microscopy, and the blood compatibility behavior, with specific attention to coagulation proteins and platelet adhesion. (C) 2014 Wiley Periodicals, Inc.