Bioactive carbon dots direct the osteogenic differentiation of human bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) have been the focus of bone regeneration due to their excellent osteogenic potential and abundant source. However, the high-cost and low-efficiency differentiation of BMSCs into functional osteoblasts limits their clinical application. It is desirable to develop bioactive materials to integrate efficient differentiation and traceable properties in a biocompatible manner for MSC-based therapy. In this study, a new kind of bioactive carbon dot (CD) was facilely fabricated through a one-step hydrothermal method from adenosine and aspirin. These bioactive CDs were cytocompatible and biosafe with the capability of long-term fluorescent tracking of human bone marrow mesenchymal stem cells (hBMSCs). Notably, the presence of bioactive CDs triggered and directed a series of events that followed the temporal pattern of osteogenic differentiation through the promotion of osteogenic transcription and enhancement of matrix mineralization. Moreover, cells with bioactive CDs exhibited more effective osteogenic differentiation behavior than cells treated with either adenosine or aspirin alone. Overall, these findings clearly showed that adenosine and aspirin-based CDs can direct osteogenic differentiation of hBMSCs in the absence of any external osteoinductive factors. The unique properties of bioactive CDs could provide insight into their potential for achieving efficient and safe MSC-based therapy.