FIG. 1.

Calibration of shear stress in microfluidic chamber. (A) Schematic of experimental setup. High-speed pressure servo was connected to a microfluidic chamber to generate controlled fluid shear stimuli. (B) Comparison of triggering voltage pulse (red) and pressure rise (black) at inlet of the chamber, showing a rise time of 1 ms can be achieved. (C) Trajectory of microbeads under a flow pulse of 6.5 kPa for 10 ms. The image was collected from the middle plane of the chamber, ∼50 μm from the bottom. Blue arrow indicates flow direction. (D) Dependence of average shear stress on inlet pressure. Maximum flow rate was estimated from the length of the streaks and shear stress calculated as described in Methods. Each data point was averaged from >8 streaks in each frame for a total of 10 frames of four experiments. Error bar indicates standard error of the mean. Color image is available online at www.liebertpub.com/neu