Ultrasound-triggered piezoelectric polyetheretherketone with boosted osteogenesis via regulating Akt/GSK3β/β-catenin pathway

Maxillofacial bone defects can severely impact quality of life by impairing physiological functions such as chewing, breathing, swallowing, and pronunciation. Polyether ether ketone (PEEK) is commonly used for the repair of maxillofacial defects due to its mechanical adaptability, while its osteogenic properties still need refinement. Herein, we have utilized the piezoelectric effect exhibited by barium titanate (BTO) under low-intensity pulsed ultrasound (LIPUS) to develop an ultrasound responsive PEEK (PDA@BTO-SPEEK, PBSP) through the mediating effect of polydopamine (PDA), for repairing maxillofacial bone defects. After modification by PDA@BTO, PBSP possesses better hydrophilicity, which is conducive to cell growth and adhesion. Simultaneously, by virtue of the piezoelectric characteristics of BTO, PBSP obtains a piezoelectric coefficient that matches the bone cortex. Notably, when PBSP is stimulated by LIPUS, it can generate stable electricity and effectively accelerate the osteogenic differentiation of osteoblasts through the regulation of the Piezo1-induced calcium (Ca²⁺) influx and Akt/GSK3β/β-catenin pathway. In addition, PBSP presents satisfactory therapeutic effects in rat skull defect models, and its osteogenic efficiency can be further improved under LIPUS stimulation with high tissue penetration. Collectively, PBSP + LIPUS exhibits great potential as a promising alternative strategy for the repair of maxillofacial bone defects.