3D printing of Cu-doped bioactive glass composite scaffolds promotes bone regeneration through activating the HIF-1α and TNF-α pathway of hUVECs
Qiyuan Dai, Qingtao Li, Huichang Gao, Longtao Yao, Zefeng Lin, Dingguo Li, Shuangli Zhu, Cong Liu, Zhen Yang, Gang Wang, Dafu Chen, Xiaofeng Chen, Xiaodong Cao
Abstract
The increasing insight into the molecular and cellular processes within the angiogenic cascade assists in enhancing the survival and integration of engineered bone constructs. Copper-doped bioactive glass (Cu-BG) is now a potential structural component of the novel scaffolds and implants used in orthopedic and dental repairs. However, it is difficult for BG, especially micro-nano particles, to be printed into scaffolds and still retain its biological activity and ability to biodegrade. Additionally, the mechanisms of the copper-stimulating autocrine and paracrine effects of human umbilical vein endothelial cells (hUVECs) during repair and regeneration of bone are not yet clear. Therefore, in this study, we created monodispersed micro-nano spherical Cu-BG particles with varying copper content through a sol-gel process. Through in vitro tests, we found that Cu-BG enhanced angiogenesis by activating the pro-inflammatory environment and the HIF-1α pathway of hUVECs. Furthermore, 2Cu-BG diluted extracts directly promoted the osteogenic differentiation of mouse bone mesenchymal stem cells (BMSCs) in vitro. Then, a new 3D-printed tyramine-modified gelatin/silk fibroin/copper-doped bioactive glass (Gel/SF/Cu-BG) scaffold for rat bone defects was constructed, and the mechanism of the profound angiogenesis effect regulated by copper was explored in vivo. Finally, we found that hydrogel containing 1 wt% 2Cu-BG effectively regulated the spatiotemporal coupling of vascularization and osteogenesis. Therefore, Cu-BG-containing scaffolds have great potential for a wide range of bone defect repairs.