Vasculature-on-chip: characterizing shear stress effects on endothelial cells

Official URL: https://risc01.sabanciuniv.edu/record=b2766811_(Table of contents)

It is well known that mechanical stimuli, which have significant effects on cell biology, are the subject of an emerging field of science called mechanobiology. This is accompanied by the development of organ-on-chip as a breakthrough branch of technology and excellent in vitro models for the study of organs, diseases, tissue engineering, drug development, and the exploration of the interface between biology and physical forces. Fluid shear stress is one of the essential mechanical forces constantly acting in our vascular system due to blood flow. The endothelial cells lining the interior of the vessel directly sense the shear stress and respond accordingly. Therefore, in order to obtain an accurate organ-on-chip model, which usually includes the vessels on one side, it is essential to apply near-physiological shear stress. This research addresses the design, fabrication, and modification of a microfluidic device to model vessels and characterizes endothelial cell shear. The goal was to approximate in vivo shear conditions by setting a constant flow rate and investigating the effects of other parameters. Viscosity, size, and geometry were considered as parameters based on theoretical shear stress expressions. The results support the conclusion that there is a significant morphological response when the viscosity of the flow increases, which was not observed when other parameters were changed. In addition, a novel observation in this field is that endothelial cells function better when the spatial gradient of shear stress is high (viscosity-dominated) than when the temporal gradient of shear stress is high (velocity-dominated).