A robust, low swelling, and lipid-lubricated hydrogel for bionic articular cartilage substitute.

Healthy articular cartilage can achieve high load-bearing capacity and the most effective lubricated surface. Inspired by the articular cartilage, a lipid-lubricated hydrogel with excellent mechanical strength and remarkable lubrication was designed and synthesized. The lipid-lubricated hydrogel could contribute to high strength and stiffness (compressive strength of 5.8 MPa and compressive modulus of 4.7 MPa at 50% strain), and it could recover more than 98% of original mechanical properties in a short time after loading-unloading. In addition, the friction coefficient of lipid-lubricated hydrogel is low as 0.026, 5.3 times smaller than hydrogel without adding the liposomes. Overall, the hydrogel we studied holds the potential as a load-bearing soft tissue substitute for articular cartilage.