A Piezo‐Mimetic Ionic Hydrogel Harnessing Joint Motion for Cartilage Repair

ABSTRACT Articular cartilage regeneration remains challenging due to its avascular architecture and limited intrinsic repair capacity. Here, we present a piezo‐mimetic ionic hydrogel (PSG‐Mg _c ) that harnesses endogenous joint motion to orchestrate cartilage repair through mechano‐electrical coupling. The hydrogel integrates a freeze‐thaw crosslinked poly(vinyl alcohol) (PVA) backbone for mechanical resilience with sodium alginate (SA) and carboxyl‐enriched acylated gelatin (Acy‐Gel) to construct a hydrated, ion‐permissive network capable of dynamic Mg ²⁺ coordination. Unlike conventional electron‐based piezoelectric materials, PSG‐Mg _c transduces mechanical deformation into localized ionic currents via deformation‐induced asymmetric ion migration, while simultaneously enabling sustained Mg ²⁺ delivery to modulate cellular metabolism. This dual mechano‐electrical coupling and biochemical regulation enhance chondrocyte activity and promote extracellular matrix synthesis in vitro. In anatomically distinct trochlear and femoral condylar defect models, the hydrogel exhibits load‐adaptive functionality, generating amplified bioelectric cues under higher mechanical stress and achieving near‐native cartilage restoration. By coupling mechanical energy harvesting with ion‐mediated electrochemical signaling, PSG‐Mg _c establishes a new paradigm that shifts cartilage repair from passive scaffolding toward active mechano‐electrical coupling regeneration.