FIG. 1.

Schematic diagram of the device for chemotaxis assay. (a) Overall design of the device is presented with the direction of diffusion and cell migration (upper right box: a perspective view of the device mainly focused on the agarose channels and observation region). (b) Image and description of the microdevice with magnified view of cell migration channel, observation region, and agarose gel channels. (c) Flow chart of experimental process. (d) A filling process of agarose gel into microchannels which functions as a semi-permeable membrane allowing free diffusion of small molecules but preventing fluid flow in the microsystem. (e) A medium filling process in the microfluidic device. Due to their hydrophilic and gas-permeable properties of oxygen-treated PDMS microchannel, the channel was filled with a medium while pushing out the trapped air in the channel.