INTRODUCTION: Cyclic strain and fluid flow are well known to affect cell behaviour.Also,isotropic and anisotropic strain can affect cells differently.While in-vivo cells experience varying degrees of anisotropy(d.o.a.),in-vitro anisotropic strain studies have mostly focused on uniaxial strains.In this study,we determined the effects of varying d.o.a.,in combination with fluid flow shear stresses,on human umbilical vein endothelial cells(HUVECs)using a newly developed device.METHODS: The device has 100 units producing various anisotropic strains.This is achieved by stretching a polydimethylsiloxane(PDMS)membrane over circular pillars into surrounding ellipse trenches.The dimensions of the ellipse determine the d.o.a.,which is defined as the ratio of maximum to minimum principal surface strains.The presence of fluid flow channels at varying angels to the ellipses allows for the determination of combined effects of anisotropic strains and flow induced shear stresses.HUVECs were mechanically stimulated.Simultaneously,cells were subjected to fluid flow shear stresses of~5 dyne/cm2.The cells were fixed after 24 hours and stained with Alexa 488 Phalloidin and DAPI.RESULTS: Models and empirical measurements showed that strains with varying d.o.a.could be generated on the device.HUVECs aligned along the minimum principal strain direction when only strain was applied.An increase in d.o.a.resulted in increased cell alignment.Cells aligned along the flow direction when only flow was applied.When flow and strain were combined,alignment was predominantly in the direction of the flow,but an offset towards the minimum principal strain direction was detected.DISCUSSION & CONCLUSIONS: HUVECs respond to various d.o.a.The variations in response of cells highlight the need to study the effects of strains of varying d.o.a.on cells.Our device permits such experiments with an increased throughput,which makes it an important tool to better understand these mechanobiological principles.