Biomimetic,biodegradable and osteoinductive treated dentin matrix/α-calcium sulphate hemihydrate composite material for bone tissue engineering

It is still a huge challenge for bone regenerative biomaterial to balance its mechanical,biological and biodegradable properties.In the present study,a new composite material including treated dentin matrix(TDM)andα-calcium sulphate hemihydrate(α-CSH)was prepared.The optimal composition ratio between TDM andα-CSH was explored.The results indicate that both components were physically mixed and structurally stable.Its compressive strength reaches up to 5.027±0.035 MPa for 50%TDM/α-CSH group,similar to human cancellous bone tissues.Biological experiments results show that TDM/α-CSH composite exhibits excellent biocompatibility and the expression of osteogenic related genes and proteins(ALP,RUNX2,OPN)is significantly increased.In vivo experiments suggest that the addition of TDM for each group(10%,30%,50%)effectively promotes cell proliferation and osteomalacia.In addition,50%of the TDM/α-CSH combination displays optimal osteoconductivity.The novel TDM/α-CSH composite is a good candidate for certain applications in bone tissue engineering.

Treated dentin matrix induces odontogenic differentiation of dental pulp stem cells via regulation of Wnt/β-catenin signaling

Treated dentin matrix(TDM)is an ideal scaffold material containing multiple extracellular matrix factors.The canonical Wnt signaling pathway is necessary for tooth regeneration.Thus,this study investigated whether the TDM can promote the odontogenic differentiation of human dental pulp stem cells(hDPSCs)and determined the potential role of Wnt/β-catenin signaling in this process.Different concentrations of TDM promoted the dental differentiation of the hDPSCs and meanwhile,the expression of GSK3βwas decreased.Of note,the expression of the Wnt/β-catenin pathway-related genes changed significantly in the context of TDM induction,as per RNA sequencing(RNA seq)data.In addition,the experiment showed that new dentin was visible in rat mandible cultured with TDM,and the thickness was significantly thicker than that of the control group.In addition,immunohistochemical staining showed lower GSK3βexpression in new dentin.Consistently,the GSK3βknockdown hDPSCs performed enhanced odotogenesis compared with the control groups.However,GSK3βoverexpressing could decrease odotogenesis of TDM-induced hDPSCs.These results were confirmed in immunodeficient mice and Wistar rats.These suggest that TDM promotes odontogenic differentiation of hDPSCs by directly targeting GSK3βand activating the canonical Wnt/β-catenin signaling pathway and provide a theoretical basis for tooth regeneration engineering.