Graphene Quantum Dots Promotes Migration and Differentiation of Periodontal Stem Cells

Objectives: Owing to their antibacterial activity, grapheme family materials possess huge potential for bone tissue engineering, drug/gene delivery, as well as biological sensing/imaging applications. However, little is known about their applications in periodontal regeneration. This study aimed to explore the effect of graphene quantum dots (GQDs) on migration and differentiation of periodontal stem cells (PDLSCs) in vivo.
Methods: In our study, the toxicity of GQDs was evaluated by CCK-8 assay, and the expression of osteogenic, fibroblast and cementoblast marker genes were analyzed by q-PCR. Transwell was used to test the migration of PDLSCs at different concentrations of GQDs. Additionally, alizarin red S method was used to detect mineralized nodules formation.
Results: CCK-8 demonstrated that the cells was not inhibited by GQDs with the concentrations from 0 to 30 μg/ml. Transwell test showed the migration of PDLSCs was highly promoted by GQDs with a concentration of 5 and 10 μg/ml. The expressions of osteogenic marker genes, such as ALP, RUNX2 and OCN were up-regulated by GQDs, and it was similar for the expressions of fibroblast differentiation marked gene COL-Ι. However, the expression of cementoblasts marked gene CEMP-1 was down-regulated by GQDs. The alizarin red S method showed that more nodules formation of PDLSCs by GQDs than by osteoblast medium.
Conclusions: It is concluded that GQDs possess low cellular cytotoxicity and good biocompatibility; it could promote PDLSCs migration, and promote PDLSCs into osteogenic and fibroblast differentiation, but inhibit cementum differentiation.