DUAL-FUNCTIONALIZED VISIBLE-LIGHT RESPONSIVE GELATIN BIOINK AS CARTILAGE BINDING GLUE AND MATRIX FOR 3D CHONDRAL REGENERATION

Abstract

Hydrogel bioprinting holds potential for capturing the zonal architecture of native cartilage, enhancing tissue regeneration[1]. Yet, fixation of hydrogel constructs is a major challenge due to limited lateral integration and the risks of damage to the surrounding tissue upon crosslinking. The aim of this study was to develop a printable hydrogel with potential for in situ cartilage repair, based on a cell‐laden gelatin methacryloyl hydrogel modified with tyramine moieties (gelMA‐Tyr) bearing dual crosslinking capacity. Photo‐induced gelation of the reactive acryl‐ and tyramine groups was triggered in one step via visible‐light irradiation using Ru/SPS. GelMA‐Tyr and gelMA were loaded with articular cartilage progenitor cells and cultured in vitro. Both gelMA and gelMA‐Tyr supported cell survival and chondrogenesis in terms of viability, glycosaminoglycans production and compressive modulus. GelMA‐Tyr exhibited shear‐thinning behaviour and could be printed using an extrusion‐based platform, while showing shape retention post‐printing[2]. The tissue‐binding capacity was studied using a push‐out test upon casting in chondral explants. The visible‐light tyramine‐methacryloyl dual crosslinking showed 15‐fold the adhesive strength to native cartilage compared to Irgacure‐gelMA. Moreover, the Ru/SPS visible‐light crosslinking system resulted on average on 57% higher cell viability of surrounding native cartilage when compared to UV‐Irgacure crosslinking. Ru/SPS crosslinkers did not show oxygen inhibition, facilitating the use of the gel in situ. Overall, visible‐light crosslinkable gelMA‐Tyr hydrogels in combination with the dual crosslinking mechanism triggered by Ru/SPS demonstrated potential for direct delivery and integration into damaged cartilage. Its potential as a bioink enhances the possibilities for the repair of complex, patient‐specific defects.