Combined light-cured and sacrificial hydrogels for fabrication of small-diameter bionic vessels by 3D bioprinting

BACKGROUND: Bionic grafts can replace autologous tissue through tissue engineering in cases of cardiovascular disease. However, small-diameter vessel grafts remain challenging to precellularize. OBJECTIVE: Bionic small-diameter vessels with endothelial and smooth muscle cells (SMCs) manufactured with a novel approach. METHODS: A 1-mm-diameter bionic blood vessel was constructed by combining light-cured hydrogel gelatin-methacryloyl (GelMA) with sacrificial hydrogel Pluronic F127. Mechanical properties of GelMA (Young's modulus and tensile stress) were tested. Cell viability and proliferation were detected using Live/dead staining and CCK-8 assays, respectively. The histology and function of the vessels were observed using hematoxylin and eosin and immunofluorescence staining. RESULTS: GelMA and Pluronic were printed together using extrusion. The temporary Pluronic support was removed by cooling during GelMA crosslinking, yielding a hollow tubular construct. A bionic bilayer vascular structure was fabricated by loading SMCs into the GelMA bioink, followed by perfusion with endothelial cells. In the structure, both cell types maintained good cell viability. The vessel showed good histological morphology and function. CONCLUSION: Using light-cured and sacrificial hydrogels, we formed a small ca bionic vessel with a small caliber containing SMCs and endothelial cells, demonstrating an innovative approach for construction of bionic vascular tissues.