Biodegradable Piezo-triboelectric Charge Nanogenerator Patch for Cartilage Regeneration

Cartilage degradation is a hallmark of osteoarthritis. Restoring the natural bioelectric environment of osteoarthritic tissue could offer a promising treatment strategy through physical modulation. We report a microsized, biodegradable implantable patch that utilizes a piezoelectric effect-enhanced triboelectric charge generator (PTEG) to promote cartilage regeneration and osteoarthritis healing. Featuring a triboelectric architecture with macroscopic pyramids and microscopic porosities, the PTEG patch produces a charge density of 242 μC m^-2 in vitro and 84 μC m^-2 in vivo, approximately 2 orders of magnitude higher than that of the state-of-the-art implantable charge generators. Additionally, the PTEG patch demonstrates excellent biocompatibility and tunable degradability. In vitro experiments show that the PTEG significantly promotes bone marrow stem cell migration, Ca²⁺ influx, and chondrogenic gene expression. In an osteoarthritis rat model, PTEG implantation was shown to reduce osteophyte formation and enhance cartilage regeneration significantly.