Using microfluidic channel networks to generate gradients for studying cell migration.

In this chapter, we will discuss a method for the generation of gradients that can be quantitatively used for studying directional cell migration. Microfluidic networks, which serially split and remix small volumes of solutions under laminar flow conditions to generate a series of microchannels of increasing protein concentration. At a juncture of these microchannels, where a single broad channel is formed, a protein concentration gradient can be easily achieved. This method is highly useful because of the ability with which we can control, manipulate and analyze chemical gradients and cells' chemotactic behavior in a quantitative manner.