Bioactive Electrode System With External Connectivity for Electrically Augmented Bone Regeneration

Electrical stimulation (ES) potentially promotes bone regeneration by recapitulating endogenous bioelectric cues. However, existing ES delivery systems often prioritize stable electrical interfacing with power supply devices but neglect the creation of conducive osteogenic microenvironment, or lack reliable power connectivity, hindering the in vivo application of electrically augmented therapies for bone defects. To integrate the controlled ES and osteogenic commitment, a bioactive electrode system comprised of a porous conductive scaffold embedded with silver filaments was developed in this study. The scaffold was fabricated via a facile freeze-drying method from a composite of gelatin, PEDOT:PSS, and strontium-doped hydroxyapatite, which exhibited suitable porous structure, electrical conductivity and ion release. In vitro assays confirmed the biocompatibility of the scaffold and its potential to promote osteogenic differentiation of BMSCs and angiogenesis of HUVECs, particularly when combined with ES. Finally, the efficacy of the bioactive system for electrically augmented bone regeneration in vivo was demonstrated in a rat cranial defect model, achieving a 2.6-fold increase in bone volume/total volume at 12 weeks of implantation compared to the control group. By integrating electrical signal transmission via silver filaments electrodes to construct a pro-osteogenic microenvironment, this bioactive electrode system offers a promising strategy for electrically augmented bone regeneration.