Volumetric bioprinting and melt electrowriting have been used to produce functional blood arteries, which is a ground-breaking development in tissue engineering. This ground-breaking method has enormous potential for organ transplantation and regenerative medicine. While melt electrowriting uses an electrohydrodynamic technique to generate microfibers, volumetric bioprinting uses bioinks to precisely layer-by-layer deposit three-dimensional structures. Researchers have successfully printed complex blood artery networks with excellent accuracy and usefulness by combining these two techniques. A revolutionary development in tissue engineering has The resulting constructions display important traits such proper endothelial cell alignment, enough mechanical strength, and an adequate supply of nutrients. This ground-breaking accomplishment addresses the long-standing problem of vascular integration and paves the way for the creation of complex vascularized tissues and organs. Melt electrowriting and volumetric bioprinting together mark a substantial advancement in tissue engineering and move us one step closer to the possibility of bioprinting functional organs. In this project, melt electrowriting and volumetric bioprinting were effectively coupled for the first time. This combines the efficiency of volumetric printing with the cell-friendliness necessary to produce functional blood arteries. The research from the Regenerative Medicine Centre Utrecht (RMCU) biofabrication lab was released today in Advanced Materials. The RMCU biofabrication lab invented the volumetric printing method for bioprinting in 2019. It is a quick method that enables cells to endure the printing procedure. However, because this kind of printing is carried out in gels that are hospitable to cells, the final prints are not very sturdy structurally. Blood vessels, which need to be able to resist high pressures and flex, are affected by this. This is the reason why Melt electrowriting and volumetric bioprinting were combined. A tiny filament of molten (biodegradable) plastic is directed in a specific direction during the process of melt electrowriting, a sort of highly accurate 3D printing. It can create complex scaffolds that can withstand force and are mechanically sturdy. The drawback is that due to the high temperatures involved, they cannot be directly printed with cells in them. Therefore, in this instance, cell-laden gels were solidified onto the scaffolds via volumetric bioprinting. How to combine volumetric printing and electrowriting Melt electrowriting is used to create a tubular scaffold at the beginning of the procedure. This is subsequently inserted in a vial filled with photoactive gel and the volumetric bioprinter. The gel that lies inside, on top of, or surrounding the scaffold can theoretically be selectively solidified using the laser of the printer. Größbacher and colleagues evaluated different scaffold thicknesses in this investigation, which produced tubes that were either stronger or weaker. Finally, they experimented with different positions for the bioprinted gels. These could be positioned on the scaffold's inside side, inside the scaffold, or outside of it. The scientists printed a proof-of-concept blood artery with two layers of stem cells using two distinct labelled stem cells, and then seeded epithelial cells in the centre to fill the lumen of the channel. Using tubes to create working vessels The design might also permit holes in the side of the print, allowing for controlled vessel permeability for blood to do its purpose. Last but not least, the scientists also produced more intricate designs, including forked vessels and even vessels with venous valves that worked to preserve a unidirectional flow. Größbacher: "This investigation served as a proof of concept. The stem cells must now be swapped out into functional cells that make up a true blood artery. This entails surrounding the epithelial cells with more fibrous tissue and muscle cells. Now, we want to print a working blood vessel. Source: University Medical Center Utrecht Journal reference: Größbacher, G., et al. (2023) Volumetric Printing across Melt Electrowritten Scaffolds Fabricates Multi-Material Living Constructs with Tunable Architecture and Mechanics. Advanced Materials. doi.org/10.1002/adma.202300756.