| description abstract | I am pleased to introduce this special issue of the Journal of Fluids Engineering—Transactions of the ASME on microfluidics. The term “microfluidics†is typically used to refer to the study of fluid dynamics in channels or systems with scales of the order of tens to hundreds of microns. The high surfacetovolume ratios and small volumes implicit in a microfluidic system enable engineering functionality that is not possible in a macroscale fluid system. Arguably, microfluidics grew out of both molecularbased fields (molecular analysis and molecular biology) and engineering methods/applications. While the success of microanalytical methods may have led to some of the earliest interest in developing microfluidic systems [1], the involvement of the fluids engineering community grew markedly in the 1990s. During this time period, microelectronics fabrication methods began being leveraged for use in fluid systems and the Defense Advanced Research Projects Agency (DARPA) in the U.S. made a significant investment in microfluidics research programs. These DARPA programs were aimed primarily at microfluidicsbased biological or chemical sensing systems. Such “labonachip†systems were viewed as advantageous for various reasons, including a small required sample volume, low perdevice cost (because of bulk manufacturing), portability, and disposability, among others. All of these attributes are particularly valuable for fielddeployable sensors. | |