Harnessing Fiber Orientation in Agarose‐Encapsulated Polyvinyl Alcohol Hydrogel Film for Superior Function in Artificial Heart Valves: Physicochemical, Mechanical, and In Vitro Biological Studies

ABSTRACT

Polyvinyl alcohol (PVA) hydrogels have adjustable mechanical properties and good biocompatibility, with broad prospects in heart valve replacement. Constructing PVA hydrogels with biomimetic structure and anisotropic mechanical properties has become a research hotspot due to the directional collagen layer of heart valves. In this study, agarose (AG) is utilized not only as a reinforcing agent but also as a modifier to enable the formation of a biomimetic, fiber‐oriented hydrogel film. By exploiting the temperature‑dependent crosslinking of AG, we fabricate a hydrogel film via shear force induction, with a well‑aligned fibrous microstructure (mean fiber diameter 0.16 ± 0.03 μm). Mechanical evaluations reveal that the oriented hydrogel film gelled at 60°C achieves optimal performance, with tensile tangent modulus values ranging from 0.31 to 4.01 MPa perpendicular to the fiber direction and 0.33–6.05 MPa parallel to the fibers. Corresponding tensile strengths reach 1.75 and 2.63 MPa, respectively, satisfying the mechanical demands of pulmonary valve tissue. Furthermore, in vitro assays demonstrate excellent cytocompatibility (cell viability > 92%) and hemocompatibility (hemolysis rate < 2%). These findings highlight that the oriented PVA‑AG hydrogel film, combining anisotropic mechanics and biocompatibility, is a promising biomimetic material for artificial heart valves.