Physical-Crosslinkable Hyaluronic Acid Derivative to Prepare Shear-Thinning Hydrogel for 3D PrintingTuesday (18.06.2019) 20:23 - 20:24
Despite the progress that has been made by scientists over the last two decades to develop hydrogels that are able to meet the criteria of 3D-bioprinting, further improvements are still needed to overcome the technical and biological challenges that hinder the development of this important technique. In the present study, hyaluronic acid polymer (HA) of Mw = 76.6 kDa was hydrophobically modified by introducing hexadecyl chains onto its polymer backbone using substitution reaction as a synthetic route. The 1HNMR spectrum of the resulting product showed that the degree of substitution of the primary hydroxyl groups of HA was 40 mol%. The modified polymer could form a stable hydrogel at relatively low polymer concentration 0.4 wt% whereas unmodified HA could not form a hydrogel even at polymer concentration of 1.6 wt%. Additionally, the rheological properties of the 1.6 and 2.5 wt% hydrogels were investigated using first continuous flow experiments which showed a remarkable decreasing of the hydrogels viscosity by increasing the shearing rate indicating that both hydrogels own shear-thinning property. Furthermore, the cyclic strain time sweep rheology experiments demonstrated that both hydrogels have rapid self-healing property since they showed at high strains sharp decreases in their storage modules, which were instantly recovered when only low strain was applied. The printability of both hydrogels was tested using an extrusion-based 3D printer at room temperature. The 2.5 wt% hydrogel showed higher shape fidelity after the 3D printing than the 1.4 wt% hydrogel. Conclusion and Outlook: hydrophobically modified HA could be a promising polymer to prepare hydrogels with shear-thinning property that can be used as a bioink in the field of 3D-bioprinting, which will be tested soon in our labs. Acknowledgment: the authors would like thanks J. Groll, T.Jüngst (University Hospital Würzburg) for the scientific support and European Research Council (ERC) for the financial support.