(299f) Directional Oscillating Shear in Conventional and Novel Culture Dishes

Wall shear stress (WSS) on anchored cells affects their responses, including cell proliferation, morphology, and gene expression. WSS is two-dimensional. We previously developed a new directional oscillatory shear index (DOSI) to quantify the directionality of oscillating shear. DOSI is unity for uniaxial flow for any nonzero amount of shear reversal, and zero for bi-axial oscillations of equal magnitudes.  Results indicated that more, smaller and less elongated cells grew in bi-axial shear with nearly equal oscillatory fluctuations (low DOSI), and fewer, larger cells with greater elongation were promoted in uniaxial oscillatory shear (high DOSI).  Statistical analyses of the individual and interacting effects of multiple factors showed that DOSI significantly affected all the responses, indicating that directionality is an important determinant of cellular responses. 

   A widely-used, convenient platform for studying these responses is flow in a cylindrical dish in orbital motion on a shaker table, such as in multiple well plates.  Computational modeling shows that WSS varies substantially with radial location within the dish. DOSI approached zero for biaxial oscillatory shear of equal magnitudes near the center and approached one for uniaxial pulsatile shear near the wall, where large tangential WSS dominated a much smaller radial component. We introduce here novel-geometry dishes designed to reduce the variability of WSS across the dish, which was quantified by comparing DOSI characteristics with that in conventional cylindrical dishes.