Hydrogel-polyurethane fiber composites with enhanced microarchitectural control for heart valve replacement

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Regenerative Medicine

Background:

• Current prosthetic heart valves face limitations in durability and the need for anticoagulation therapy.
• Developing single-phase polymeric materials with suitable biological and mechanical properties for heart valves is challenging.
• Composite materials offer a potential solution by combining tunable mechanical properties with thromboresistant surfaces.

Purpose of the Study:

• To develop and evaluate a novel composite heart valve material combining an electrospun polyurethane mesh with a hydrogel coating.
• To assess the biological responses, including platelet/bacterial attachment and calcification, compared to traditional pericardial valves.
• To investigate the hemodynamic performance and optimize the fiber microarchitecture for enhanced durability.

Main Methods:

• Fabrication of a composite material using electrospun polyurethane mesh for mechanical properties and a hydrogel coating for thromboresistance.
• Evaluation of biological responses (platelet/bacterial attachment, calcification) against glutaraldehyde-fixed pericardium.
• Development of a 3D-printed hydrogel coating setup for device-level hemodynamic testing.
• Advanced electrospinning techniques (variable mandrel velocity, annealing, conical mandrel) to control fiber microarchitecture (alignment, tortuosity, curvilinearity).

Main Results:

• The composite material demonstrated significant reductions in platelet (38%) and bacterial (98%) attachment, and calcification (59%) compared to pericardium.
• Hemodynamic testing met ISO 5840-2:2021 requirements, with a regurgitation fraction of 9.6% and effective orifice area of 1.52 cm², comparable to clinical bioprosthetic valves.
• Advanced electrospinning achieved controlled fiber alignment (NOI 85.1% ± 1.4%) and introduced tortuosity/curvilinearity mimicking native valve structures.

Conclusions:

• The hydrogel-polyurethane fiber composite shows promise as a durable and thromboresistant heart valve material.
• Optimized fiber microarchitecture through advanced electrospinning is crucial for improving strain homogeneity and leaflet durability.
• Future research will integrate advanced electrospinning with model-directed fabrication to further enhance heart valve longevity.