Blood-contacting properties of polydimethylsiloxane polyurea-urethanes

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Materials Engineering

Background:

• Polyurethanes are widely used biomaterials.
• Enhancing polyurethane properties, particularly for blood-contacting applications, remains a key research area.
• Silicone-based polyurethanes offer unique properties but require optimization for specific applications.

Purpose of the Study:

• To synthesize and characterize novel silicone-urea polyurethanes.
• To investigate the effect of silicone oligomer molecular weight on polymer properties.
• To evaluate the blood compatibility and surface properties of these new materials.

Main Methods:

• Synthesis of polyurethanes using amino-terminated polydimethylsiloxane oligomers and hexane diisocyanate.
• Extension of oligomers to introduce internal urea linkages in the soft segment.
• Evaluation of surface properties using dynamic contact angle measurements.
• Assessment of blood compatibility via a canine ex vivo shunt, measuring platelet and fibrinogen deposition.

Main Results:

• The synthesized silicone-urea polyurethanes exhibited improved tensile properties compared to those without urea linkages.
• Dynamic contact angle measurements provided insights into surface characteristics.
• The silicone-urea polyurethanes demonstrated favorable blood-contacting properties when compared to a standard polyetherurethane.
• Polymers derived from higher molecular weight silicone oligomers showed the lowest deposition of platelets and fibrinogen.

Conclusions:

• Incorporating internal urea linkages enhances the mechanical and interfacial properties of silicone-based polyurethanes.
• The developed silicone-urea polyurethanes possess promising hemocompatibility for biomedical applications.
• Higher molecular weight silicone oligomers contribute to superior blood compatibility, indicated by reduced protein and cell adhesion.