Effects of Low-Concentration Graphene Oxide Quantum Dots on Improving the Proliferation and Differentiation Ability of Bone Marrow Mesenchymal Stem Cells through the Wnt/β-Catenin Signaling Pathway

[Image: see text] Graphene oxide quantum dots (GOQDs) are considered to be a new method for regulating the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs). However, there are few reports on such regulation with different concentrations of GOQDs, and the molecular mechanism has not been fully elucidated. The purposes of this study were, first, to explore the effects of GOQDs on the proliferation and differentiation of BMSCs in vitro and in vivo, and, second, to provide a theoretical basis for the repair of bone defects. Live/Dead staining, EdU staining, immunofluorescence staining, alkaline phosphatase (ALP), western blotting, and qT-PCR were used for detecting the proliferation and differentiation of BMSCs after coculture with GOQDs of different concentrations. Hematoxylin and eosin (HE) staining and Van Gieson (VG) staining were used to detect new bone regeneration in vivo. The results showed that low-concentration GOQDs (0.1 and 1 μg/mL) promoted the proliferation and differentiation of BMSCs. Compared with the 1 μg/mL GOQD group, the 0.1 μg/mL GOQD group had better ability to promote the proliferation and differentiation of BMSCs. HE and VG staining results showed the greatest proportion of new bone area on sandblasted, large-grit, and acid-etched (SLA)/GOQD scaffolds. Furthermore, the ratio of active β-catenin and the phosphorylation level of GSK-3β (p-GSK-3β) increased after BMSCs treatment with 0.1 μg/mL GOQDs. Low concentrations of GOQDs improved the osteogenic differentiation ability of BMSCs by activating the Wnt/β-catenin signaling pathway.