The Effect of Tensile Force and Periodontal Ligament Cell-Laden Calcium Silicate/Bioinks Auxetic Scaffolds for Tissue Engineering

The biofabricate technologies has allowed us to manufacture complex novel scaffolds for tissue regeneration. In this study, we demonstrated the incorporation of different concentrations of ceramic powder into fish gelatin methacrylate (FGelMa) bioink for the fabrication of CS/FGelMa auxetic bioscaffolds using bioprinting technology. Our results indicated that ceramic could be successfully incorporated into FGelMa bioink without effecting the structural components of FGelMa. Furthermore, it conveyed that ceramic modifications both the mechanical properties and degradation rates of the scaffolds were improved in accordance with the concentrations of ceramic upon modifications of ceramic. In addition, the presence of ceramic promoted the adhesion and proliferation of human periodontal ligament cells (hPDLs) cultured in the scaffold. Further osteogenic evaluation also confirmed that ceramic was able to enhance the osteogenic capabilities via activation of downstream intracellular factors such as pFAK/FAK and pERK/ERK. More interestingly, it was noted that the application of extrinsic biomechanical stimulation to the auxetic scaffolds further enhanced the proliferation and differentiation of hPDLs cells and secretion of osteogenicrelated markers when compared to CS/FGelMa hydrogels without tensile stimulation. This prompted us to explore the related mechanism behind this interesting phenomenon. Subsequent studies showed that biomechanical stimulation works via YAP, which is a biomechanical cue. Taken together, our results showed that novel auxetic scaffolds could be fabricated by combining different aspects of science and technology, in order to improve the future chances of clinical applications for bone regeneration.