Biomimetic Gradient Lubrication Hydrogel Contrived by Self-Reinforced MOFs Nanoparticle Network

• Self-reinforced network of metal-organic frameworks nanoparticles significantly improved the mechanical strength and durability of the hydrogel. • Biomimetic lubricating hydrogels with architectural and compositional gradients enabled by multi-material 3D printing. • Slippery hydrogel meniscus substitutes with complicated gradient structures and reliable cushioning layers were manufactured. • The gradient architecture stiffness can be modulated by controlling the spatial distribution of MOFs, achieving low friction (~0.1141) and high fracture strength (~2.50 MPa).