Figure 2: Establishing chemical gradient.
(A) Fluorescence images of rhodamine B-conjugated dextran (70 kDa) visualized the concentration gradient of the molecule under the fluid flow of 0.125, 0.5 and 2 μl/min. (B) The intensity profile of the fluorescence image showed that the concentration gradient in the device is adjustable by the flow rate. The error bars indicate standard deviations.