"Extreme"Microfluidics: Large-volumes and Complex Fluids

Microfluidics gained prominence with the application of microelectromechanical systems (MEMS) to chemistry and biology in an attempt to benefit from the miniaturization of devices for handling of minute fluid samples under precisely controlled conditions. The field of microfluidics exploits the differences between microand macro-scale flows, for example, the absence of turbulence, electro-osmotic flow, surface and interfacial effects, capillary forces in order to develop scaled-down biochemical analytical processes. The field also takes advantage of MEMS and silicon micromachining by integrating microsensors, micro-valves, and micro-pumps as well as physical, electrical, and optical detection schemes into microfluidics to develop the so-called “micro-total analysis systems (μTAS)” or “lab-on-a-chip” devices. The use of silicon in the early years of miniaturization during 1980s was self-limiting to the growth of the field of microfluidics primarily due to its high cost and inaccessibility of manufacturing, and to some extent due to its incompatibility with light microscopy. After mid 1990s there has been a major leap in progress with the application of soft lithography using polydimethylsiloxane to engineer complex microfluidics devices as well as the ability to manufacture plastics at a micron scale resolution.