In situ swelling of low-friction, high load-bearing self-bending bilayer hydrogels inspired by articular cartilage.

The articular cartilage is characterized by its gradient hierarchical structure, which exhibits excellent lubrication and robust load-bearing properties. However, its inherent difficulty in self-repair after damage presents numerous formidable challenges for cartilage repair. Inspired by the unique structure of articular cartilage, a biomimetic bilayer hydrogel composed of PAM (polyacrylamide) and PAM/SA (sodium alginate) is prepared using a two-step in-situ swelling method.