Isotropically Robust Hydrogel with Biomimetic Multilayer Fibrous Architecture.

Soft materials like hydrogels hold great promise for biomedical and engineering applications. While various strengthening and toughening methods have been developed, they often produce anisotropic structures or require specific liquid conditions to maintain enhanced mechanical properties. Inspired by the hierarchical collagen architecture of articular cartilage, we report here a biomimetic multilayer fibrous hydrogel that overcomes these limitations. Through controlled stacking of aligned fibrous monolayers, we create a hierarchical structure exhibiting exceptional isotropic mechanical properties while maintaining full functionality, regardless of liquid environments. Additionally, our hydrogel demonstrates remarkable crack resistance under both static and cyclic loading conditions, sustaining 10,000 loading cycles without structural degradation. Our work establishes a generalized framework for designing hydrogels with isotropically high mechanical performance and structural durability without dependence on specific liquid environments, opening new possibilities for load-bearing applications in biomedical devices and soft robotics where both mechanical reliability and aqueous stability are essential.