Coaxial Embedded Printing of Gelatin Methacryloyl–alginate Double Network Hydrogel for Multilayer Vascular Tubes

The reconstruction of vascular-like tissues exhibiting a typical three-layer structure in vitro is vital to bio-fabrication research. It enables the realization of more complicated micro-environments, such as myocardium, liver, and tumor, which enables us to investigate their specific physiological phenomena or pathological mechanisms. Herein, we propose a coaxial embedded printing method, where the gelatin methacrylate (GelMA)–alginate composite hydrogel and sacrificial materials are extruded from a coaxial nozzle into a cylinder mold. By applying this method, we achieve the rapid fabrication of multilayer tube structures with inner diameters ranging from 400 to 1000 µm. In addition, myoblasts are encapsulated in the hydrogel, and the cells show high viability. Moreover, we encapsulate smooth muscle cells (SMCs) and the human umbilical vein endothelial cells–T1 (HUVEC-T1) cell line in the hydrogel to form vascular-like tissues, and the cells exhibit good morphology and protein expression. These results suggest that a vascular tube fabricated using the proposed method can serve as a vascular model for in vitro studies.