MEMS shear stress sensors for microcirculation

Coronary artery disease is the leading cause of morbidity and mortality in the industrialized nations. Both biochemical and biomechanical stimuli modulate the pathogenesis of coronary artery diseases. Shear stress acting on the lumen of blood vessels intimately modulates the biological activities of vascular endothelial cells (ECs). We hereby develop micro electro mechanical system (MEMS)-based sensors at the dimension comparable to a single EC to monitor real-time shear stress in a micro fluidic channel. Our goal is to fabricate sensors for shear stress measurement at low Reynolds number commonly encountered in human microcirculation. The MEMS sensors are designed based on the previously described heat transfer principles. The polysilicon was doped with phosphorous in order to increase the resistivity of the sensing element at 2.5 kΩ. The development of backside wire bonding enabled the application for the vascular geometry. The small dimension (80 μm × 2 μm) and the gain amplitude at 71 kHz offers an entry point to measure shear stress with high spatial and temporal resolution.