3D Printed Elastomer‐Hydrogel Composite Meniscal Scaffolds with Biomimetic Gradient Structure and Robust Interface for Preventing Osteoarthritis and Repairing Meniscal Injuries

Abstract Meniscal implants with biomimetic 3D architecture, gradient mechanical properties, and excellent biocompatibility are urgently required due to the increasing incidence of meniscus injuries. Inspired by the microstructure of the meniscus, which consists of a meshwork interwoven with collagen fibers and a hydrophilic matrix filled with glycosaminoglycans and chondrocytes, here a type of structurally and functionally optimized meniscal scaffolds is prepared. Direct‐ink‐writing 3D printing technology is utilized to construct an elastomeric skeleton with a biomimetic 3D and gradient microstructure, and then hydrogel resin is infiltrated into the skeleton, resulting in an elastomer‐reinforced hydrogel composite meniscal scaffold through co‐curing of the elastomer and hydrogel resins. The composite meniscal scaffolds exhibit a highly porous structure and biomimetic gradient mechanical properties by controlling the ratio of elastomer and hydrogel materials. The co‐curing of the two materials creates robust interfaces through strong covalent bonding, ensuring their reliable long‐term mechanical performance. Furthermore, the coexistence of aqueous and oily phases of the emulsion‐type hydrogel resin allows the loading of both water‐soluble and lipid‐soluble drugs, endowing the composite scaffolds with a diphasic drug‐release capacity. The composite scaffolds are then implanted in the knee joints of beagle canines, successfully promoting the repair of meniscal injury and tissue regeneration.