Impact of Bi-Axial Shear on Atherogenic Gene Expression by Endothelial Cells.

This study demonstrated the effects of the directionality of oscillatory wall shear stress (WSS) on proliferation and proatherogenic gene expression (I-CAM, E-Selectin, and IL-6) in the presence of inflammatory mediators leukotriene B4 (LTB4) and bacterial lipopolysaccharide (LPS) from endothelial cells grown in an orbiting culture dish. Computational fluid dynamics (CFD) was applied to quantify the flow in the dish, while an analytical solution representing an extension of Stokes second problem was used for validation. Results indicated that WSS magnitude was relatively constant near the center of the dish and oscillated significantly (0-0.

An orbital shear platform for real-time, in vitro endothelium characterization.

Electrical impedance techniques have been used to characterize endothelium morphology, permeability, and motility in vitro. However, these impedance platforms have been limited to either static endothelium studies and/or induced laminar fluid flow at a constant, single shear stress value. In this work, we present a microfabricated impedance sensor for real-time, in vitro characterization of human umbilical vein endothelial cells (HUVECs) undergoing oscillatory hydrodynamic shear.

Spatial and temporal resolution of shear in an orbiting petri dish.

It is well documented that physiological and morphological properties of anchored cells are influenced by fluid shear stress. Common orbital shakers provide a means of simultaneously applying shear stress to cells for tens to hundreds of cases by loading the shaker with multiple dishes. However, the complex flow in orbiting dishes is amenable to analytical solution for resolving shear created by the fluid motion only for simplified conditions.