Optimized design of a multichannel integrated nozzle for extrusion-based 3D bioprinting: balancing cell viability and printing precision

Purpose This paper aims to address cell damage and structural defects caused by high shear stress within the nozzle and frequent nozzle switching during extrusion-based three-dimensional (3D) bioprinting by optimizing the design of a multichannel integrated nozzle to achieve a balanced trade-off between printing precision and cell viability. Design/methodology/approach A combined numerical simulation and experimental validation approach was used to compare different multichannel flow-channel geometries, with particular emphasis on their effects on shear stress distribution and flow velocity stability within the nozzle. A 10% gelatin solution was used as the bioink, and its rheological behavior was characterized using the Herschel–Bulkley model. The corresponding rheological parameters of the bioink under different temperature conditions were further analyzed to guide the optimization of the nozzle structure. Findings The results indicate that the optimized multichannel integrated nozzle structure can significantly reduce peak shear stress in critical regions of the nozzle while maintaining flow stability. Subsequent printing experiments further confirm that the nozzle achieves high forming quality while ensuring a high level of cell viability. Originality/value This study proposes a coordinated optimization strategy for multichannel integrated nozzle design in extrusion-based 3D bioprinting by combining rheological modeling, numerical simulation and experimental validation, thereby achieving a comprehensive optimization of printing precision and cell viability. The findings provide valuable theoretical insights and practical engineering guidance for the design and optimization of nozzle structures in multicellular extrusion-based bioprinting.