3D-printed triaxial nozzles fabricated by stereolithography to prevent backflow in soft matter biofabrication

Three-dimensional (3D) bioprinting has a significant influence on tissue engineering by virtue of its capacity to produce complicated structures with complex geometries that are challenging to recreate using conventional manufacturing methods. However, the nozzle design and fabrication remain a limitation within extrusion-based 3D bioprinting, restricting and compromising the overall potential of this technology. The proposed nozzle design combines three Luer-Lok compatible inlets and an outlet within the printed body, eliminating manual assembly and enhancing fabrication consistency and quality. Furthermore, a finite element analysis of the fluid flow in the nozzle demonstrated the effectiveness of the nozzle to minimize backflow, in comparison with a traditional nozzle design. The tetrameric IIZK (Ac-Ile-IIe-Cha-Lys-NH₂) and IIFK (Ac-Ile-IIe-Phe-Lys-NH₂) peptide bioinks were used to 3D-print a variety of 3D scaffolds of varying complexity, with good resolution and gel continuity. Our work successfully demonstrated the fabrication of a novel design and its potential, and by means of 3D bioprinting, we assessed the biocompatibility and cell viability of the cell-laden constructs. This study highlights the capability of the novel design, which aids the field of tissue engineering, allowing 3D extrusion-based bioprinting to be utilized in the production of cell-incorporated constructions or scaffolds.