Fluidigm of South San Francisco, Calif., has received US Patent No. 8,168,139, "Recirculating fluidic network and methods for using the same." The patent provides a variety of microfluidic devices and methods for conducting assays and syntheses. The devices include a solid substrate layer having a surface that is capable of attaching ligand and or anti-ligand, and an elastomeric layer attached to the surface. They also include deflectable membrane valves and pumps, for example, rotary pumps.