NIST Engineers Use Microfluidics to Build a Dropper That Meters Out One Molecule at a Time

Oct. 20, 2009
NIST engineers use microfluidics to build a dropper that meters out one molecule at a time.
National Institute of Standards and Technology, www.nist.gov

Engineers at the National Institute of Standards and Technology have developed a microfluidic “droplet-on-demand” device that spits out droplets about 1 micrometer in diameter (or about half a billionth of a billionth of a liter) that contain a single molecule of a compound of interest. Their goal is to give material scientists and chemical engineers a way to observe chemical reactions between single molecules

The device has a channel through which water flows. The water, which has been laced with molecules of interest to a specific concentration, is squeezed into a narrow stream by a mixture of oils whose viscosity or resistance to flow exerts pressure on it. The water then enters a narrow constriction in the channel and its pressure drops abruptly. Adding detergent at this point breaks up the water’s surface tension, splitting it into small droplets of uniform size. And their size can be adjusted by changing the width of the constriction. The resulting droplets pick up on average just one of the molecules of interest.

Currently, researchers use lasers to move and merge two or more single-molecule-carrying droplets into one larger droplet. They can then watch any chemical reactions using various optical methods.

Sponsored Recommendations

June 27, 2025
Ensure workplace safety and compliance with our comprehensive Lockout/Tagout (LOTO) Safety Training course. Learn critical procedures to prevent serious injuries.
June 27, 2025
Join our expert webinar to discover essential safety control measures and best practices for engineering a truly safe and compliant industrial environment.
June 25, 2025
An innovative aircraft with electric drives combines the best of both worlds. The cross between drone and helicopter could mean significantly faster and more efficient air emergency...
June 25, 2025
Effective when other materials fail, ceramics are particularly suitable for applications requiring wear and chemical resistance, sliding characteristics or biocompatibility. Discover...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!