Electrosensitive Heterogeneous Short Fibers via Acousto-Electric Coupling for Sequential Bone Regeneration in Infectious Defects.

Abstract

The disruption of dynamic equilibrium between antimicrobial and osteogenic processes, caused by the heterogeneous electro-sensitivity of bacteria and host cells, is central to the high failure rate in repairing infected bone defects. This study collected clinical data and systematically analyzed the limitations of electrical stimulation in bone repair. Consequently, electrosensitive heterogeneous short fibers are innovatively developed, achieving sequential regeneration of infected bone defects through acousto-electric coupling. First, barium titanate nanoparticles with excellent piezoelectric properties are synthesized by ion substitution doping (BaTiO₃@Fe). Next, the catechol groups of polydopamine served as multifunctional anchors for the in situ deposition of "conductive" graphene oxide and "piezoelectric" BaTiO₃@Fe onto short fibers, facilitated by π-π conjugation and coordination interactions, resulting in the formation of 3D integrated electrosensitive heterogeneous short fibers. At an ultrasound intensity of 1.5 W cm^{- 2}, the system efficiently activates bacterial peroxisome and necroptosis pathways, promoting bacterial apoptosis. At a lower intensity of 0.5 W cm^{- 2}, it activates the TRPV4/Ca²⁺/YAP signalling axis, enhancing the osteogenic differentiation of bone marrow-derived mesenchymal stem cells. By employing a spatiotemporal differential electrical regulation strategy, this coupling approach effectively cascades antimicrobial and osteogenic effects, restoring the electro-microenvironment homeostasis of bone tissue and significantly accelerating the repair of infected bone defects.