Bionic Triboelectric Nanogenerator Activates the “mechano‐electro‐biochemical” Cascade Effect In Situ to Accelerate Critical‐Sized Bone Defect Repair

The loss of the intrinsic "mechano-electro-biochemical" cascade effect in critical-sized bone defects (CSBDs) impedes the bone self-healing process. Traditional strategies cannot provide bionic electrical output, thereby failing to sufficiently activate the "mechano-electro-biochemical" cascade effect in situ and limiting the repair efficiency of CSBDs. Here, a bionic, self-adhesive, and biodegradable triboelectric nanogenerator (TENG) called PPCs-TENG using silk-fibroin-derived peptide (Cs)-grafted polydopamine-polyacrylamide (PPCs) as the electrode layer is fabricated. It provides bionic electrical stimulation (bio-ES) in response to the host's motion status. It reestablishes the resting potential during host rest and generates real-time biofeedback action potential during host movement. Further, it activates the "mechano-electro-biochemical" cascade effect for accelerating the repair of CSBDs. The bio-ES generated from PPCs-TENG enriches extracellular osteogenesis-related biochemical factors at the CSBD site. It also activates the intracellular mechanosensitive protein Piezo1, thereby promoting calcium signaling and intracellular mechano-transduction pathways. This activation enhances the proliferation and migration of bone marrow stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs), and promotes osteogenic differentiation in BMSCs and angiogenesis in HUVECs. In vivo tests demonstrate that PPCs-TENG significantly accelerates the repair of CSBDs in situ.