Fiber-reinforced hydrogels: From multiscale structural design to advanced engineering applications

Hydrogels are high-water-content polymer networks similar to those of soft tissues and have shown immense potential in fields such as tissue engineering, flexible electronics, and intelligent sensors. However, traditional hydrogels still face challenges such as low mechanical strength, poor toughness, and susceptibility to fatigue. Inspired by tough natural soft tissues (such as muscles and tendons), the introduction of a robust fibrous network into hydrogels enables effective stress transfer, crack bridging, and energy dissipation, thus overcoming the mechanical limitations of traditional hydrogels. This paper reviews fiber-reinforced hydrogels prepared from different reinforcing fibers (e.g., natural, synthetic, inorganic, and carbon-based), as well as the interfacial interactions between the fibers and the matrix (including physical entanglement, dynamic noncovalent bonds, and covalent bonds), and summarizes the preparation methods, such as in situ infiltration, directional freezing, and 3D printing. It also discusses their applications in the fields of medicine, sensing, and wearable devices and finally provides an outlook on current challenges such as precise interface regulation and large-scale intelligent manufacturing.