Micro flow systems for chemical and biochemical applications

Micromachining, based on photolithography commonly used in the integrated circuit, has been applied to miniaturize chemical and biochemical total analysis systems (TAS). Micro/miniaturized total analysis systems (µTAS) realize very small sample volume, fast response and reduction of reagents which is very useful in biochemical analysis. Reduction of waste is also an advantage when toxic reagents are required. The majority of µTAS developed so far are flow type analysis systems in which the analyses are completed in continuous flow, for example, a flow injection analysis (FIA) and a gas chromatography (GC). The flow type µTAS are classified into two groups. One is a MEMS (Micro Electro Mechanical System) type system including mechanical flow control devices of microvalves and micropumps.^1,2 The other uses electrically driven liquid handling without mechanical elements. Typically, electroosmotic flow has been used so far. Planer capillary electrophoresis (chip CE) type systems are the common application of this method.³ Micromachining technologies are diversified to fabricate chemical and biochemical micro reactors as well as µTAS.⁴ Examples of micro flow systems and their components for chemical and biochemical applications are described.