Researchers at the National Institute of Standards and Technology have added another innovation — miniature valves — to their ever-growing collection of inexpensive, easy-to-manufacture and highly efficient microfluidic devices made from plastic films and double-sided tape.
Traditionally, microfluidic devices — tiny gadgets with fluid-carrying channels used in "lab-on-a-chip" chemical analyzers, medical diagnostics and DNA forensics — have been fabricated like microchips using photolithography. A desired pattern of micrometer-sized channels and ports is created on top of a silicon substrate, which can then be replicated many times by techniques such as molding or embossing. The process requires specialized cleanroom equipment and can take several days to complete. If valves are needed in the system, they traditionally have been made from silicones. Unfortunately, silicones are not the best materials to use with particular laboratory assays or for manufacturing lab-on-a-chip structures.