Graphene family nanomaterials(GFNs)are highly popular in the field of bone tissue engineering because of their excellent mechanical properties,biocompatibility,and ability to promote the osteogenic differentiation of stem cells.GFNs play a multifaceted role in promoting the bone regeneration microenvironment.First,GFNs activate the ad-hesion kinase/extracellularly regulated protein kinase(FAK/ERK)signaling pathway through their own micromorphology and promote the expression of osteogenesis-related genes.Second,GFNs adapt to the mechanical strength of bone tis-sue,which helps to maintain osseointegration;by adjusting the stiffness of the extracellular matrix,they transmit the me-chanical signals of the matrix to the intracellular space with the help of focal adhesions(FAs),thus creating a favorable physiochemical microenvironment.Moreover,they regulate the immune microenvironment at the site of bone defects,thus directing the polarization of macrophages to the M2 type and influencing the secretion of relevant cytokines.GFNs also act as slow-release carriers of bioactive molecules with both angiogenic and antibacterial abilities,thus accelerating the repair process of bone defects.Multiple types of GFNs regulate the bone regeneration microenvironment,including scaffold materials,hydrogels,biofilms,and implantable coatings.Although GFNs have attracted much attention in the field of bone tissue engineering,their application in bone tissue regeneration is still in the basic experimental stage.To promote the clinical application of GFNs,there is a need to provide more sufficient evidence of their biocompatibility,elucidate the mechanism by which they induce the osteogenic differentiation of stem cells,and develop more effective form of applications.

The dynamic balance between bone formation and bone resorption is a critical process of bone remodeling.The imbalance of bone formation and bone resorption is closely associated with the occurrence and development of various bone-related diseases.Under both physiological and pathological conditions,non-coding RNAs(ncRNAs)play a crucial regulatory role in protein expression through either inhibiting mRNAs translation or promoting mRNAs degradation.Circular RNAs(circRNAs)are a type of non-linear ncRNAs that can resist the degradation of RNA exonucleases.There is accumulating evidence suggesting that circRNAs and microRNAs(miRNAs)serve as critical regulators of bone remodeling through their direct or indirect regulation of the expression of osteogenesis-related genes.Additionally,recent studies have revealed the involvement of the circRNAs-miRNAs regulatory network in the process by which mesenchymal stem cells(MSCs)differentiate towards the osteoblasts(OB)lineage and the process by which bone marrow-derived macrophages(BMDM)differentiate towards osteoclasts(OC).The circRNA-miRNA network plays an important regulatory role in the osteoblastic-osteoclastic balance of bone remodeling.Therefore,a thorough understanding of the circRNA-miRNA regulatory mechanisms will contribute to a better understanding of the regulatory mechanisms of the balance between osteoblastic and osteoclastic activities in the process of bone remodeling and the diagnosis and treatment of related diseases.Herein,we reviewed the functions of circRNA and microRNA.We also reviewed their roles in and the mechanisms of the circRNA-miRNA regulatory network in the process of bone remodeling.This review provides references and ideas for further research on the regulation of bone remodeling and the prevention and treatment of bone-related diseases.