Figure 8.

Shear-induced activation of neutrophils. (A) Maximum shear stress within the flow module occurs at the intersection of vertical access ports and horizontal microchannel (red arrows); based on the simulation, the maximum shear stress is 0.4 dynes.cm⁻² at an inlet flow rate of 10 µL.min⁻¹ and neutrophils should not become activated by the fluid dynamics within the flow module. (B) Upon exposure of neutrophils to IL-8 or shear stresses above 1.5 dynes.cm⁻², they become activated and shed the surface marker, L-selectin. Quantitative analysis of neutrophil activation based on L-selectin loss shows that the percentage of activated neutrophils in the negative control and flow module are not statistically different, while the positive control with neutrophils treated with 10 ng.ml⁻¹ of the cytokine IL8 shows a significant statistical difference (*p < 0.05, n = 4).