Rapid Fabrication of Tendon-inspired Ultrastrong, Water-rich Hydrogel Fibers: Synergistic Engineering of Cyano-<i>p</i>-aramid Nanofibers and Poly(vinyl alcohol)

Abstract

Load-bearing fibrous tissues, like tendons, have remarkable strength with high water content (similar to 60%) due to the anisotropic network of collagen fibers. However, the scalability of biomimetic anisotropic hydrogels is limited by time-intensive fabrication processes involving cross-linking and stretching, often spanning several hours to days. Here, we present a rapid, scalable approach for fabricating tendon-mimetic hydrogel fibers within 1 min using the synergistic engineering of cyano-p-aramid nanofibers (CY-ANFs) and poly(vinyl alcohol) (PVA). Through continuous air-gap spinning, the formation of the anisotropic CY-ANF network drives instant gelation, producing hundreds of meters of hydrogel fibers without additional gelation treatment. From the perspective of properties, the hydrophilic PVA matrix affords flexibility, while the hydrophobic CY-ANF network provides a nonswelling feature and load-bearing ability, resulting in ultrastrong, water-rich hydrogel fibers. These hydrogel fibers exhibit a water content exceeding 80 wt %, along with exceptional strength (similar to 17.9 MPa), surpassing the mechanical properties of natural tendons (strength and modulus of approximately 10 and 100 MPa, respectively). Lengthy hydrogel fibers are integrated into larger-sized fabrics by knitting or weaving while also possessing strain-sensing capabilities. With excellent biocompatibility, these hydrogel fibers are promising candidates for artificial fibrous tissues and various biotechnological applications.