Nonthrombogenic, biodegradable elastomeric polyurethanes with variable sulfobetaine content.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Medical Device Engineering

Background:

• Degradable polymers for blood contact require high thromboresistance.
• Surface modifications for thromboresistance can be transient with degradation.
• Bulk polymer design offers a more durable solution for thromboresistance.

Purpose of the Study:

• To synthesize and characterize biodegradable, elastic polyurethanes (PESBUUs) with varying zwitterionic sulfobetaine (SB) content.
• To evaluate the mechanical properties, degradation, and thromboresistance of these novel polymers.
• To assess their suitability for blood-contacting applications.

Main Methods:

• Synthesis of PESBUUs using polycaprolactone-diol (PCL-diol) and SB-diol mixtures, diisocyanatobutane, and putrescine.
• Characterization of chemical structure, mechanical properties (tensile strength, strain), thermal properties, hydrophilicity, biodegradability, fibrinogen adsorption, and thrombogenicity.
• Electrospinning for vascular conduit fabrication.

Main Results:

• Increased SB content led to some reduction in wet tensile properties and enzymatic degradation.
• PESBUUs with 50% and 75% SB content exhibited wet tensile strength >15 MPa and breaking strain >500%.
• Markedly reduced thrombotic deposition was observed before and after degradation; electrospinning yielded compliant vascular conduits.

Conclusions:

• Tunable PESBUUs with optimized zwitterionic content demonstrate enduring thromboresistance and suitable mechanical properties for degradable blood-contacting applications.
• These materials offer a promising alternative to transient surface modifications.
• The developed polyurethanes could be utilized in vascular grafts and other implantable devices.