Optimizing nozzle design in extrusion-based 3D bioprinting to minimize mechanical stress and enhance cell viability

Extrusion-based 3D bioprinting is a widely used technique for fabricating cell-laden constructs in tissue engineering and regenerative medicine. However, the mechanical stresses experienced by cells during the printing process can negatively impact their viability. This study examines the influence of nozzle geometry—specifically contrac- tion angle and outlet diameter—on stress distribution and its effects on cell survival. Through a combination of experimental analysis and theoretical modeling, we explore how nozzle design affects the balance between shear and extensional stresses during bioprinting. The findings highlight the importance of optimizing nozzle parameters to minimize mechanical damage and improve post-printing cell viability. The pro- posed model provides a framework for guiding nozzle design, offering insights for the development of customized bioprinting strategies that enhance construct fidelity and biological functionality. These results contribute to advancing bioprinting techniques for applications in tissue engineering and regenerative medicine.