Abstract

Fabrication of artificial heart valves with a dual network structure via frozen phase separation technique. • Tensile strength of BNC/PVA composite membranes is 8–12 times higher than that of pure BNC membranes. • Suture retention of BNC/PVA composite was increased by 3 times and burst pressure exceeded 1400 mmHg. • In vitro calcium deposition level demonstrated excellent anti-calcification properties. • Assembled valves complied with ISO 5840-3:2021, showing comparable to natural valves. The development of polymer heart valves remains challenging due to limitations in mechanical durability and calcification resistance. Bacterial nanocellulose (BNC) membranes exhibit excellent biocompatibility but insufficient mechanical strength for valve applications. Polyvinyl alcohol (PVA) combines good biocompatibility and excellent mechanical properties. Therefore, BNC/PVA (BP) composite membranes were prepared via frozen-phase separation for heart valve applications. This process preserves the BNC nanofibre network while embedding PVA as a reinforcing phase to form a second network, thereby constructing a synergistically reinforced hybrid dual-network structure. The BP composites showed significantly improved mechanical performance, with tensile strength increased by 8–12-fold compared with pure BNC, suture retention strength reaching 2.04 N (4× higher). After 28 days in simulated body fluid, calcium deposition remained below 11 mg/g, significantly lower than glutaraldehyde-treated tissues. BP membranes were sutured onto transcatheter aortic valve stents and evaluated using pulsatile flow testing. The assembled valves met the requirements of ISO 5840-3: 2021, with an effective orifice area of 3.43 cm 2 and a regurgitant fraction of 19.68%. BP-15 membranes exhibited enhanced endothelial cell viability and spreading, along with favorable hemocompatibility, including a hemolysis rate below 0.2%. These results indicate that BP composites are a promising alternative for du