P34: PRINTABILITY & CYTOCOMPATIBILITY TESTING OF XANTHAN GUM FOR EXTRUSION-BASED 3D BIOPRINTING IN WOUND HEALING

Abstract

Abstract Introduction Bioprinting facilitates highly-specific deposition of skin cells and biomaterials. Skin bioprinting is still limited by prolonged printing processes, poor mechanical properties and incomplete complexities. An important barrier is identifying an ideal hydrogel for skin bioprinting – one with a good balance between printing viable cells and producing robust scaffolds. Herein, three hydrogels were tested for potential use as bio-inks. Method A pneumatic-extrusion Inkredible 3D bioprinter was used. Initially, different concentrations of Alginate (reference), XG and Alginate/XG mixture were quantitatively evaluated for printability by calculating aspect ratio, square printability and cylinder height. The best two printable concentrations of each hydrogel were selected to undergo hDF viability testing to assess the effect of the printing process (Nozzle diameter and viscosity). The best concentration for each hydrogel group with best cell viability then underwent a 14-day hDF cytocompatibility testing period by using Live/dead staining, metabolic activity, dsDNA and collagen quantification. Result XG revealed a remarkable ability to build 3D shapes (XG(6%) with 27G nozzle-10.0mm±0.2 cylinder height). XG(6%), Alginate/XG(4%/10%) and Alginate(6%) were identified as the best concentrations to undergo 14-day cytocompatibility testing. XG(6%) and Alginate/XG(4%/10%) had better day 1 hDF viability (87.3%±2.9; 87.6%±1.5, respectively) than Alginate(6%)(74%±2.65). All hydrogels had gradually improving cell viability. Cell proliferation remained comparable amongst all hydrogels. Moreover, collagen production was confirmed in all constructs. Conclusion Bioprinted XG is cytocompatible with hDF still further optimisation of XG is required to prolong its degradability to optimise its application as a hydrogel for skin bioprinting. Abbrev XG–Xanthan gum; hDF–human Dermal Fibroblasts Take-home message There is still no ideal hydrogel identified for the purpose of skin bioprinting. An updated systematic review should be carried out to assess the current best available hydrogels.