Effects of Shear and Extensional Stresses on Cells: Investigation in a Spiral Microchannel and Contraction-Expansion Arrays.

In recent decades, inertial microfluidic devices have been widely used for cell separation. However, these techniques inevitably exert mechanical stresses, causing cell damage and death during the separation process. This remains a significant challenge for their biological and clinical applications. Despite extensive research on cell separation, the effects of mechanical stresses on cells in microfluidic separation have remained insufficiently explored. This review focuses on the effects of mechanical stresses on cells, particularly in spiral microchannels and contraction-expansion arrays (Contraction and Expansion Arrays (CEAs)). We derived the approximated magnitude of shear stress in a spiral microchannel, extensional stress in CEAs and conventional methods, along with exposure time in a single map to illustrate cell damage and operational zones. Finally, this review serves as a practical guideline to help readers in evaluating stress damages, enabling the effective selection of appropriate techniques that optimize cell viability and separation efficiency for biological and clinical applications.