Jiandi Wan1, William D. Ristenpart1, Catherine Best2, Renita Horton3, Guido Guidotti4, Edward H. Abraham5, and Howard A. Stone3. (1) School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138, (2) Harvard Institute of Medicine, Boston, 02215, (3) School of Engineering and Applied Sciences, Harvard University, Cambridge, 02138, (4) Department of Molecular and Cellular Biology, Harvard University, Cambridge, 02138, (5) the Department of Oncology Services and Radiation Oncology, Saints Medical Center, Lowell, 01852
To understand the influence of shear stress on the kinetics of adenosine triphosphate (ATP) release from red blood cells (RBCs), we mimic arterial constrictions using a series of channels in microfluidic devices. The shear stress and duration of stress are systematically varied in different devices by changing the width and length of the channels respectively. We show that the amount of released ATP increases roughly exponentially with the magnitude of the shear stress, but that there is a critical duration of stress (> 2 ms) required for RBCs to release significant amounts of ATP. For durations greater than 8 ms, however, the amount of ATP decreases. The results suggest that RBCs are sensitive not only to the diameter of arterial constrictions but to their length, an effect with important physiological and medical implications.