A Graphene Oxide-Copper Nanocomposite For The Regeneration Of The Dentin-Pulp Complex: An Odontogenic And Neurovascularization-Inducing Material

Dentin-pulp complex tissue engineering is a promising novel therapy in endodontics. Materials currently used in regenerative endodontics, e.g., calcium hydroxide and mineral trioxide aggregate, do not ensure full regeneration of the dentin-pulp complex, especially in terms of neurovascular induction. In this study, we fabricated a water-soluble graphene oxide-copper nanocomposite (GO-Cu) and investigated its odontogenic and neurovascularization-inducing abilities by means of dental pulp stem cells (DPSCs). Low-dose (<= 10 mu g/mL) GO-Cu had no effect on DPSC viability and promoted proliferation and adhesion. DPSCs treated with GO-Cu differentiated into odontoblasts and secreted larger amounts of vascular endothelial growth factor (VEGF) and glia-derived neurotrophic factor (GDNF) just as when they were cultured on a GO-Cu-coated calcium phosphate cement (CPC/GO-Cu) scaffold. Human umbilical vein endothelial cells treated with GO-Cu showed more tube formation, higher VEGF expression, and a stronger migratory ability. In addition, immunomodulatory genes, including indoleamine 2,3-dioxygenase (IDO), human leukocyte antigen G (HLA-G), and hepatocyte growth factor (HGF), were upregulated in DPSCs by the GO-Cu treatment. When CPC/GO-Cu was transplanted subcutaneously into nude mice, dentin-pulp complex-like structures formed expressing dentin sialophosphoprotein (DSPP), CD31, and GAP43, and the mineralized area and blood vessel numbers were greater in the CPC/GO-Cu group than CPC-alone group. These results show odontogenic and neurovascularization-inducing abilities of GO-Cu and suggest its promising application in regenerative endodontics.