Cartilage‐Inspired Layered Hydrogel Integrating High Load‐Bearing Capacity and Excellent Lubrication

ABSTRACT Hydrogels are widely regarded as the most promising biomimetic cartilage material due to their uniquely suited combination of a hydrated 3D network and mechanical functionality, effectively mimicking the critical features of native tissue. Inspired by the layered structure and surface lubrication mechanism of articular cartilage, a bilayer composite hydrogel with high toughness and low friction was synthesized via UV‐initiated sparse chemically interlinked and carboxyl‐Fe 3+ coordination (UV‐SCIRP). This hydrogel exhibits outstanding mechanical properties, achieving a compressive strength of 8.3 MPa and a compressive modulus of 5.81 MPa at 75% strain. Notably, its original mechanical properties can recover to over 97% within a short period after loading–unloading cycles. Furthermore, the bilayer composite hydrogel demonstrates a remarkably low friction coefficient of 0.036, representing a 63.6% reduction compared to that of the bottom hydrogel. In addition, preliminary biocompatibility assessments confirm that the hydrogel supports cell adhesion and proliferation, indicating good cytocompatibility and potential for in vivo application. In summary, this cartilage‐inspired layered lubricating hydrogel successfully integrates high load‐bearing capacity, low friction, and favorable biocompatibility, offering a promising approach for developing high‐performance biomimetic articular cartilage materials.