Fig. 2.
(a) The concentration gradient was modeled in MATLAB assuming a flow rate of 1 μl min−1. Cross sectional profiles were validated experimentally at (b) 1 mm, (c) 4 mm, and (d) 8 mm down the microchannel. Circles represent experimental observations, solid lines represent the model, and dashed lines represent the linear fit. A flow rate of 1 μl min−1 was used in the experiment.