Pectin/hyaluronic acid-based berry-bionic injectable Janus bilayer hydrogel with in-situ sequential crosslinking for...

Existing Janus hydrogels for preventing postoperative tendon adhesion often neglect adequate mechanical protection and lubrication required for tendon regeneration. Inspired by the structural and functional synergy of berry exocarp with anti-adhesion and protection properties as well as mesocarp with adhesion, cushioning and antioxidant capacities, we fabricate a bilayer Janus hydrogel (PPDP) based on pectin and hyaluronic acid via a one-pot injectable in-situ sequential crosslinking strategy. The bottom layer is constructed with catechol-functionalized hyaluronic acid and adipic dihydrazide-modified pectin, which achieves stable tendon adhesion and favorable mechanical cushioning and over 90% reactive oxygen species scavenging capacity. The top layer, formed by photo-crosslinkable methacrylate-modified pectin and poly (ethylene glycol) diacrylate, robust hydrated anti-adhesive barrier with low friction coefficient of approximately 0.1 after more than 8000 friction cycles and its compressive strength is markedly enhanced in comparison with natural hydrogels up to 0.5 MPa. Remarkably, in the in vivo tendon injury model, PPDP integrates barrier protection, dynamic lubrication and anti-inflammation to achieve synergistic effects of structures and components. It accelerates tendon repair during the critical acute adhesion stage, outperforming the commercial Interceed™. This biomimetic design significantly inhibits tendon adhesion and facilitates functional recovery, providing a multifunctional integrated innovative strategy for clinical practice.