Fiber composite hydrogels and their applications in tissue regeneration

Fiber composite hydrogels integrate natural extracellular matrix (ECM) structural mimicry, high mechanical strength, and large specific surface area of fibers with the exceptional hydration and water retention capabilities of hydrogels. Compared with pure hydrogels and fiber scaffolds used in tissue regeneration, these composites achieve balanced and synergistic performance. Currently, various fabrication strategies including blending, lamination, 3D printing, and in situ phase separation are employed to construct them. They exhibit significant improvements over pure hydrogel systems in structural biomimicry precision, mechanical properties, and active ingredient delivery. Thus, they demonstrate better performance than single-component materials in nerve, bone, vascular, and skin tissue regeneration, exhibiting mechanical strength and topological cues. This review systematically summarizes their preparation methods, structure-function advantages, and advances in various tissue repairs. It also offers future perspectives on performance enhancement, process optimization, and intelligent design. STATEMENT OF SIGNIFICANCE: Fiber composite hydrogels are promising biomaterials for tissue regeneration. They integrate the natural extracellular matrix structural mimicry, high mechanical strength, and large specific surface area of fibers with exceptional water retention capabilities of hydrogels, overcoming limitations of conventional hydrogels in applications. Prior reviews have narrowly centered on electrospun fibers and their reinforcing effects, lacking comprehensiveness. Alternatively, some suffer from a broad scope on applications. This review expands fiber types, compares diverse fabrication techniques, and addresses tissue regeneration. It also highlights the benefits of fiber integration including extracellular matrix mimicry, mechanical reinforcement, and delivery of active ingredients. This review covers biomaterial fabrication techniques, structure-performance correlations, and focuses on the significant societal challenge of tissue regeneration, offering strong appeal for readers.