A self-powered sandwich-structured scaffold with dual-electroactive properties to regenerate damaged intervertebral discs after discectomy

Discectomy is the most commonly used surgery in treating herniation-induced nerve compression, but it often destroys the structural integrity and leaves a defect in the intervertebral disc (IVD), leading to re-herniation risk. Considering that electric signals play a crucial role in tissue regeneration, a dual-electroactive scaffold was fabricated to promote the repair effect of the discectomy-left IVD defect. An electroconductive scaffold (G10) was 3D-printed firstly by doping graphene to form electro-osmotic networks in a polycaprolactone (PCL) matrix, then tetragonal barium titanate (T-BT) doped polyvinylidene fluoride (PVDF) fibrous membranes (B5) with piezoelectricity were electrospun on both the upper and lower surfaces of G10 to obtain a sandwich-structured scaffold (G10B5) with both piezoelectric and electroconductive activities. The <i>in vitro</i> experimental results confirmed that the dual-electroactive G10B5 scaffold could well mimic the electroconductive properties of natural IVDs and harvest ambient mechanical energy to produce electrical stimuli, thus recruiting surrounding stem cells. Following implantation in defective IVDs of rats, the dual-electroactive scaffolds could effectively decrease the loss of cells and extracellular matrix (ECM) and maintain the composite cartilage structure of IVDs. The dual-electroactive scaffold with a sandwich structure is proposed here to provide a novel strategy for treating the IVD defects after discectomy and broaden the application of electroactive biomaterials in tissue regeneration.