Piezoelectric heterojunction/polyetherketoneketone composite with enhanced sonodynamic efficacy and nanozyme activities for anti-infection and encouraging neurovascular ossification

Treatment of infected bone faces dual challenges of biofilm removal and pro-osteogenesis. Herein, a piezoelectric heterojunction of bismuth (Bi)-doped sodium niobate and oxygen-vacancy cerium oxide was constructed, and a heterojunction/polyetherketoneketone composite was prepared as a bone implanted material. The doping of Bi induced the lattice distortion and bandgap reduction of sodium niobate that remarkably enhanced piezoelectricity and sonodynamic efficiency, while oxygen-vacancies caused lattice distortion of cerium oxide that improved nanozyme activities. Under radiation of ultrasound (US), the piezoelectric effect of the composite enhanced sonodynamic performance and oxidant nanozyme activities that generated abundant reactive oxygen species (ROS) for eradicating bacteria and eliminating biofilm, and controlling infection, both in vitro and in vivo. Moreover, the piezoelectric effect not only enhanced the anti-oxidant nanozyme activities that scavenged excessive ROS for alleviating oxidative stress, but also stimulated M2 macrophage polarization that created an anti-inflammatory microenvironment for osteogenesis. Furthermore, the piezoelectric stimulation of composite boosted cellular responses (osteoblasts differentiation, angiogenesis and neurogenesis) in vitro, and promoted neuro-vascularized bone regeneration in vivo. Consequently, US-triggered piezoelectric effect of the composite displays promising potential for treatment of infected bone. This study provides a novel strategy to design piezoelectric biomaterials with nanozyme activities for preventing infection and encouraging neurovascular ossification.