1.1.1 What Is Microfluidics?

Since Richard Feynman's thought-provoking 1959 speech "There's Plenty of Room at the Bottom" [1], humanity has witnessed the most rapid technology development in its history the miniaturization of electronic devices. Microelectronics was the most significant enabling technology of the last century. With integrated circuits and progress in information processing, microelectronics has changed the way we work, discover, and invent. From its inception through the late 1990s, miniaturization in microelectronics followed Moore's law [2], doubling integration density every 18 months. Presently poised at the limit of photolithography technology (having a structure size of 100 nm), this pace is expected to slow down to doubling integration density every 24 months [3].

The development of miniaturized nonelectronic devices lagged behind the miniaturization trend in microelectronics. In the late 1970s, silicon technology was extended to machining mechanical microdevices [4] which later came to be known as microelectromechanical systems (MEMS). However, it is inappropriate, though common, to use MEMS as the term for the microtechnology that emerges today. With fluidic and optical components in microdevices, microsystem technology (MST) is a more accurate description.

The development of microflow sensors, micropumps, and microvalves in the late 1980s dominated the early stage of microfluidics. However, the field has been seriously and rapidly developed since the introduction by Manz et al. at the 5th International Conference on Solid-State Sensors and Actuators ( Transducers '89), which indicated that life sciences and chemistry are the main application fields of microfluidics [5]. Several...