Exploring the Advancements in Blood-Compatible Polyurethanes

Recent research into blood-compatible polyurethanes (PUs) has revealed promising developments in the quest for more effective biomedical materials. Studies have shown that sulfonated PUs, despite their incorporation of lysine or aspartic acid, do not exhibit significant heparin-like properties. Interestingly, an increase in sulfonate content has been linked to a longer thrombin time, marking a departure from findings related to sulfonated polystyrene resins.

In a notable advancement, researchers investigated a novel polymeric material, 2-methacryloyloxyethyl phosphorylcholine (MCP), blended with PU to enhance surface blood compatibility. The incorporation of MCP into T ecoflex® 60 demonstrated promising results, with scanning electron microscopy revealing reduced platelet adhesion even at low MCP compositions of 5 wt.%. This reduction in platelet adhesion may be attributed to diminished plasma protein adsorption on the PU-MCP membranes.

The stability of polyurethanes in vivo has also been a focus of research. New formulations were developed without polyester soft segments, instead utilizing cholesterol and phosphatidylcholine analogs. These new PUs, combined with polydiol soft segments like polybutadiene (PBD) and polyisoprene (PIP), showed minimal platelet deposition in platelet-rich plasma (PRP) experiments, highlighting the role of hydrophobic polydiols in achieving favorable blood interactions.

Further studies explored blending phospholipid diols with long-chain alkyl groups (C16 to C20) into the PUs. These combinations were recognized for their promising blood compatibility and mechanical properties. Results indicated that HPIP-based phospholipid PUs exhibited significantly lower platelet adhesion compared to standard PU formulations and controls, suggesting their potential for widespread biomedical applications.

Additionally, researchers have turned to interpenetrating polymer networks (IPNs) using α-hydroxyethyl methacrylate (HEMA)-terminated PUs. These IPNs demonstrated a favorable balance of hydrophilic and hydrophobic domains, correlating with reduced platelet adhesion. The study's quantitative platelet assessment further confirmed the success of these formulations, paving the way for innovative applications in medical devices.

These advancements in polyurethane biomaterials offer exciting possibilities for improving the compatibility of medical devices with blood, making them safer and more effective for patient use.