Coaxial Extrusion of Tubular Tissue Constructs Using a Gelatin/GelMA Blend Bioink.

Gelatin methacryloyl (GelMA) hydrogels have been commonly used in fabricating cannular tissue constructs due to their excellent cytocompatibility, as well as amenity to migration and proliferation of encapsulated cells. Here, we present a simple yet efficient approach for fabricating hollow structures with gelatin-based hydrogels using a modified microfluidic-based biofabrication technology. Hollow microfibers were generated using a customized coaxial nozzle by soft templating against a polyvinyl alcohol solution core. Reversible thermo-cross-linking and irreversible photo-cross-linking were achieved successively through gelatin (Gel) mixed into the GelMA solution and by irradiating with UV light, resulting in stable and continuous generation of hollow structures. Furthermore, in vitro evaluations confirmed good proliferation of multiple cell types in the GelMA/Gel hollow microfibers. Together, we believe that this approach holds great potential in engineering cannular constructs for applications in regenerative medicine and tissue modeling.