Figure 1.

Schematic illustration of the microfluidic device. (a) 3D schematic drawing of the PDMS microfluidic device. Green indicates CCL19 solution and orange indicates medium solution. Platinum electrodes were buried in agarose gel blocks and inserted into the electrode wells. The two electrodes were then wired to the blue (cathode) and red (anode) wires, respectively, that were connected to a DC power supply to apply electric fields to the device. The drawing of the side channels was simplified with symmetric configurations. (b) Top view drawing of the microfluidic device with the channel dimensions indicated. (c) Illustration of the cell migration experiment setup. Microfluidic device was placed on a microscope stage; dcEF was applied to the device through a pair of electrodes; chemokine and medium solutions were infused into the device through tubing from syringe pumps for generating chemical gradients; cell migration in the device was then recorded by time-lapse microscopy. (d) Illustration of cell migration data analysis in the microfluidic device. Particularly, the O.I. is defined as the ratio of the displacement of cells (Δy) relative to the electric field or the chemical gradients to the total migration distance (d) using the equation O.I. = Δy/d.