Relevance of Microsystems

Various practical problems demand that liquids be transferred from one tiny compartment to another. Three examples follow  

Analysis of a bacteria population in ambient air. The technique consists in first collecting the bacteria in a small dish, then cracking them open by means of an electric field, and finally transferring their DNA to a series of reactors, each of which contains a segment of DNA specific to a particular bacterium. If the DNA under test matches any of the references, recombination occurs, which can be observed by fluorescence methods. Everything must be done on a small scale to limit the quantities of material needed and the analysis time. 

Altering the turbulent flows near the wings of supersonic aircraft. The objective is to tailor airflows in the turbulent boundary layer using small protruding pins that control the birth of vortices. 

Ejection of drops at high velocities in high-speed printers. To promote high speed, one typically resorts to very small structures. Such structures can be etched in silicon by standard techniques. However, the resulting systems must be active in the sense that they are capable of displacing fluids. Several methods exist  

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