A nano-conductive osteogenic hydrogel to locally promote calcium influx for electro-inspired bone defect regeneration

Conductive nano-materials and electrical stimulation (ES) have been recognized as a synergetic therapy for ordinary excitable tissue repair. It is worth noting that hard tissues, such as bone tissue, possess bioelectrical properties as well. However, insufficient attention is paid to the synergetic therapy for bone defect regeneration via conductive biomaterials with ES. Here, a novel nano-conductive hydrogel comprising calcium phosphate-PEDOT:PSS-magnesium titanate-methacrylated alginate (CPM@MA) was synthesized for electro-inspired bone tissue regeneration. The nano-conductive CPM@MA hydrogel has demonstrated excellent electroactivity, biocompatibility, and osteoinductivity. Additionally, it has the potential to enhance cellular functionality by increasing endogenous transforming growth factor-beta1 (TGF-β1) and activating TGF-β/Smad2 signaling pathway. The synergetic therapy could facilitate intracellular calcium enrichment, resulting in a 5.8-fold increase in calcium concentration compared to the control group in the CPM@MA ES + group. The nano-conductive CPM@MA hydrogel with ES could significantly promote electro-inspired bone defect regeneration in vivo, uniquely allowing a full repair of rat femoral defect within 4 weeks histologically and mechanically. These results demonstrate that our synergistic strategy effectively promotes bone restoration, thereby offering potential advancements in the field of electro-inspired hard tissue regeneration using novel nano-materials with ES.