Tapered microfluidic chip for the study of biochemical and mechanical response at subcellular level of endothelial cells to shear flow.

A lab-on-a-chip application for the investigation of biochemical and mechanical response of individual endothelial cells to different fluid dynamical conditions is presented. A microfluidic flow chamber design with a tapered geometry that creates a pre-defined, homogeneous shear stress gradient on the cell layer is described and characterized. A non-intrusive, non-tactile measurement method based on micro-PIV is used for the determination of the topography and shear stress distribution over individual cells with subcellular resolution. The cellular gene expression is measured simultaneously with the shape and shear stress distribution of the cell. With this set-up the response of the cells on different pre-defined shear stress levels is investigated without the influence of variations in repetitive experiments. Results are shown on cultured endothelial cells related to the promoter activity of the shear-responsive transcription factor KLF2 driving the marker gene for green fluorescent protein.