Bioprinting with adipose stem cells and hydrogel modified with bioactive glass

Bioprinting research is focused on utilizing growth factors and multiple cell types to create clinically relevant three-dimensional (3D) tissue models using hydrogels. Rheological and biological challenges are two main factors that limit the creation of extrudable bioactive hydrogels. In this study, we investigate incorporation of fast dissolving and bioactive borate glass in different weight to volume percentages (0.075 to 0.6%) to alginate-gelatin (1:1) hydrogel to improve rheological properties and enable bioprinting with bioactive glass. The addition of glass improved the stiffness of the hydrogel. Human adipose-derived mesenchymal stem cells (ASCs) were uniformly mixed in this bioink at 1 x 10(6) cells/mL concentration, and spheroid specimens were cultured in both static and dynamic culture conditions. Gridshaped scaffolds measuring similar to 18 x 18 x 1 mm(3) were fabricated with the viable glass concentrations, and ASC viability was evaluated using Live/Dead assay. Despite immediate toxicity, an increased viability after 7 days with 0.15 w/v % or less borate glass content demonstrated the potential in utilizing highly resorbable calciumreleasing biomaterials such as bioactive glasses to modify hydrogels suitable for bioprinting cellularized 3D structures.