Lab on a chip (LOC) devicesmicrochip-size systems that can prepare and analyze tiny fluid samples with volumes ranging from a few microliters (millionth of a liter) to sub-nanoliters (less than a billionth of a liter)are envisioned to one day revolutionize how laboratory tasks such as diagnosing diseases and investigating forensic evidence are performed. However, a recent paper* from the National Institute of Standards and Technology (NIST) argues that before LOC technology can be fully commercialized, testing standards need to be developed and implemented.
"A testing standard," explains NIST physical scientist and paper author Samuel Stavis, "defines the procedures used to determine if a lab on a chip device, and the materials from which it is made, conform to specifications." Standardized testing and measurement methods, Stavis writes, will enable MEMS (microelectromechanical systems) LOC manufacturers at all stages of productionfrom processing of raw materials to final rollout of productsto accurately determine important physical characteristics of LOC devices such as dimensions, electrical surface properties, and fluid flow rates and temperatures.
To make his case for testing standards, Stavis focuses on autofluorescence, the background fluorescent glow of an LOC device that can interfere with the analysis of a sample. Stavis states that multiple factors must be considered in the development of a testing standard for autofluorescence, including: the materials used in the device, the measurement methods used to test the device and how the measurements are interpreted. "All of these factors must be rigorously controlled for, or appropriately excluded from, a meaningful measurement of autofluorescence," Stavis writes.
Quality control during LOC device manufacturing, Stavis says, may require different tests of autofluorescence throughout the process. "There may be one measure of autofluorescence from the block of plastic that is t
|Contact: Michael E. Newman|
National Institute of Standards and Technology (NIST)