Implanted Magnetoelectric Bionic Cartilage Hydrogel.

Enhancing defective cartilage repair by creating a bionic cartilage hydrogel supplemented with in situ electromagnetic stimulation, replicating endogenous electromagnetic effects, remains challenging. To achieve this, a unique three-phase solvent system is designed to prepare a magnetoelectric bionic cartilage hydrogel incorporating piezoelectric poly(3-hydroxybutyric acid-3-hydroxyvaleric acid) (PHBV) and magnetostrictive triiron tetraoxide nanoparticles (Fe3O4 NPs) into sodium alginate (SA) hydrogel to form a dual-network, semi-crosslinked chain entanglement structure. The synthesized hydrogel features similar composition, structure, and mechanical properties to natural cartilage. In addition, after the implantation of cartilage, the motion-driven magnetoelectric-coupled cyclic transformation model is triggered by gentle joint forces, initiating a piezoelectric response that leads to magnetoelectric-coupled cyclic transformation. The freely excitable and cyclically enhanced electromagnetic stimulation it can provide, by simulating and amplifying endogenous electromagnetic effects, obtains induced defective cartilage repair efficacy superior to piezoelectric or magnetic stimulation alone.