A novel multishear microdevice for studying cell mechanics

Shear stresses are known to influence the morphology, and even the fate, of many cell types, including endothelial, smooth muscle, and osteoblast cells. This paper describes a novel shear device for the study of cell mechanics. Unlike all other published shear devices, such as parallel-plate flow chambers, where a single shear stress is evaluated for a single input flow rate, the described device enables the simultaneous evaluation of 10 different shear stresses ranging over two orders of magnitude (0.7-130 dynes cm(-2), 0.07-13 Pa). Human umblical vein endothelial cells (HUVECs) were exposed to the shear stress profiles provided by the device over a 20 h perfusion period, and the secretion level of von Willebrand factor (vWF) was investigated. Confirming previous studies, increasing shear resulted in increased vWF secretion. Furthermore, changes in cell morphology, including cell and nuclear size (area) and perimeter with shear, were analysed. HUVECs under shear stresses ranging from 1-3 dynes cm(-2) (0.1-0.3 Pa) showed similar vWF content, cell and nuclear size and perimeter to static cultures, while cells under shear stresses above 5 dynes cm(-2) (0.5 Pa) showed significantly higher vWF secretion and were at least 30% smaller in cell size. We also note that cells exposed to perfusion rates resulting in a shear stress of 0.7 dynes cm(-2) (0.07 Pa) showed significantly lower levels of vWF and were 35% smaller in size than those under static conditions. Overall, the results confirm the significant utility of this device to rapidly screen cellular responses to simultaneously imposed physiologically relevant ranges of shear stress.