The haemocompatibility of polyurethane–hyaluronic acid copolymers

Despite decades of research into haemocompatible biomaterials, there remain surprisingly few materials that can be used in blood-contacting applications. We have synthesized copolymers of polyurethane (PU) with hyaluronic acid (HA) with the goal of creating materials that incorporate an inherently non-thrombogenic, biological component into the bulk polymer structure. HA was incorporated into the polymer backbone as a chain extender during PU synthesis, and the physical and biological properties of the resulting copolymer were directly controlled by the HA content. Increases in HA content led to a linear increase in hydrophilicity (R2=0.993) and corresponding increase in surface energy compared to PU controls. Elastic modulus also increased with HA content (p<0.001), while surface roughness did not significantly differ from PU controls for most PU–HA formulations. Incorporation of HA resulted in negligible platelet adhesion to the PU–HA (p<0.001), representing a 20-fold decrease in platelet adhesion compared to PU. Red blood cell adhesion also decreased with increasing HA content (p<0.001). The PU–HA materials were cytocompatible and supported endothelial cell adhesion and viability. Thus, we have demonstrated the synthesis of a copolymer whose physical and biological properties are easily tailored, and whose potent anti-thrombogenic properties demonstrate its great promise for use in vascular applications.