NIST Chemists Define And Refine Properties Of Plastic Microsystems

Microfluidics devices, also known as "lab-on-a-chip" systems, are miniaturized chemical and biochemical analyzers that one day may be used for quick, inexpensive tests in physicians' offices. Most microfluidics devices today are made of glass materials. Cheaper, disposable devices could be made of plastics, but their properties are not yet well understood.

NIST is contributing to the development of these plastic microfluidics. One study looked at how fluids flowed in plastic microchannels by tracking fluorescent dye in the fluids. NIST researchers also developed an easy technique for accurately measuring fluid temperatures--an important parameter for chemical reactions.

A third project spawned a method for concentrating and separating an ionic (charged) substance in solution within microchannels. The technique concentrates the substance as much as 10,000-fold or more, making it easier to detect in ultrasmall quantities (nanoliters--a billionth of a liter--or less).

Finally, NIST staff designed a novel system to overcome the difficult problem of slow mixing in microfluidics devices. The mixer consists of a T-shaped microchannel imprinted in plastic that is modified with a laser to create a series of slanted wells. The wells speed the mixing of two streams entering the passage.