Investigation on the effects of variable shear stress on monocyte cell morphology

Changes in flow shear stress are sensed by cell membrane receptors transferring to intracellular area that lead to physical and chemical alterations. This process is defined as mechonatransduction process that is essential for maintaining the development of cells and tissues. Vascular endothelial cells and blood cells in circulation subjected to shear stress on different levels in different regions of vascular network. There have been platforms those are fabricated by different techniques to perform in vitro cell culture experiments to reveal shear stress effects on cells. Microchannels based on PDMS fabricating by soft lithography technique have been favourable in mechanobiological applications as using for cell culture platforms, especially shear stress studies. Normally, physiological shear stress levels for veins are between 10 to 70 dynes/cm² (1-7 Pa) and for arteries between 1 to 6 dynes/cm² (0.1-0.7 Pa). In this study, a circular system has been set up by microfluidic pump to mimic physiological environment of monocyte cells for monitoring structural changes at high level shear stress. Shear stress at 12 Pa more than physiological level simulated by CFD has been applied on 8×10⁶/10 mL HL-60 cells under 3600 μL/min. during 3 hours. Cells were passed through cavitated PDMS channel. Then, cells were stained with Phalloidin-TRITC and counterstained with DAPI to monitoring fluorescence of F-Actin molecules.