Enhanced Tear Resistance and Biocompatibility of Polyurethane-Urea Elastomers for Artificial Heart Valves via...

Valvular heart disease imposes a heavy global clinical burden, and conventional mechanical and bioprosthetic valves struggle to achieve an optimal balance between long-term durability and in vivo biocompatibility. Siloxane polyurethane urea (SiPUU) serves as a commonly used polymer matrix for heart valve research owing to its intrinsic favorable cytocompatibility. Nevertheless, its insufficient tear resistance and inferior cyclic fatigue properties render it incompatible with the surgical suturing and forming procedures of prosthetic heart valves. To overcome the mechanical bottlenecks of existing polyurethane valve materials, we engineered a library of polyurethane-urea thermoplastic elastomers (Fuwai Material (J), FWJ series) by embedding abundant N-H moieties along the polymer backbone to amplify intermolecular hydrogen-bonding interactions. The top-performing variant 2NO-FWJ delivers a suite of valve-matching superior mechanical properties: a tear strength of 158.64 N/mm (55.07% higher than conventional polyurethane matrices), an elongation at break of 1686.80%, and a Young's modulus of 15.74 MPa. Under simulated physiological circulation, the material maintains robust structural integrity beyond 200 million fatigue cycles while presenting ideal hemodynamic metrics (effective orifice area ≥1.99 cm2 and transvalve pressure differential ≤11.6 mmHg). Distinct from prior polymer biocompatibility assessments relying on immortalized cell lines, this work pioneers biocompatibility characterization utilizing multiple types of primary human cardiac cells. In vitro biological characterizations suggest that 2NO-FWJ displays mild cellular toxicity, limited protein adhesion, moderate antidegradation ability against enzymes, and favorable hemocompatibility. Benefiting from hydrogen-bond-reinforced intermolecular networks, the developed FWJ elastomers simultaneously resolve the insufficient tear resistance and poor long-term fatigue durability of prevailing polymeric valve substrates and display immense translational potential for surgical suturable artificial heart valve fabrication.