Acousto-Electric Conversion Fiber Networks via Regional Activation of Schwann Cell-Derived Exosomes for Neurogenic...

Neurogenic bone regeneration is essential for the effective restoration of bone tissue functionality, with exosomes derived from Schwann cells regionalized in bone injury tissue playing a crucial role in this process. However, precisely regulating the secretion of Schwann cells localized in bone injury tissue to enhance neurogenic bone regeneration remains a considerable challenge. In this study, an injectable, ultrasound-responsive piezoelectric conductive short fiber network (US@SFG) was innovatively developed using uniform short fiber homogenization techniques and multifunctional chemical modifications, enabling precise acoustic-electrical conversion that regionally activated the secretion of miRNAs from Schwann cell-derived exosomes, thereby promoting neurogenic bone regeneration. The incorporation of the piezoelectric polymer glycine imparts superior piezoelectric characteristics to the fiber network, while the conjugated π-electron motion within the conductive graphene network enhances internal electron transfer efficiency, thereby facilitating electrical conductivity. Compared with traditional piezoelectric fiber networks, acousto-electric conversion fiber networks demonstrated a 1.7-fold increase in piezoelectric performance and a 30-fold increase in conductivity, facilitating precise electrochemical regulation under ultrasound stimulation. In vitro studies revealed that acousto-electric conversion fiber networks precisely modulate the secretion of localized Schwann cell exosomal miRNAs (miRNA-494-3p, miRNA-381-3p, and miRNA-369-3p), activating the phosphatidylinositol 3-kinase/protein kinase B and Wnt signaling pathways in bone marrow mesenchymal stem cells, and thereby promoting osteogenic differentiation. Furthermore, in vivo experiments confirmed that under ultrasound imaging guidance, acousto-electric conversion fiber networks could be directed precisely to bone defects, where precise control of ultrasound parameters facilitated acoustic-electrical conversion and electrical signal modulation, markedly promoting the formation of neural networks and bone tissue regeneration. In this study, for the first time, an injectable acousto-electric conversion fiber network was constructed to activate Schwann cell exosomes in bone injury tissue regionally, providing a novel therapeutic strategy and potential molecular targets for neurogenic bone regeneration.