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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Fast Reactions From Tiny Mixer
17 April 1998 8:00 pm
Scientists will soon be able to get a peek at exactly what proteins do in the first few microseconds of folding. A report in an upcoming issue of Physical Review Letters explains how minute quantities of fluids can be mixed together in less than 10 microseconds, at least five times faster than the speediest mixing times to date. This will allow researchers to control chemicals that switch the folding mechanism on and off fast enough to catch a protein in the act of bending.
Just as milk blends into coffee much more quickly if the liquids are stirred, researchers speed chemicals into solution by shaking them. Until the turbulent mixture settles down, however, it is impossible to see what the protein is doing. Moreover, large quantities of often expensive samples are required if researchers want to mix samples by inducing turbulence. James Knight and his colleagues at Princeton University built on an idea put forth about 2 years ago that solved both these problems: To get fluids to combine faster, give them less room to mix. In other words, he says, use an incredibly tiny coffee cup.
To make their tiny mug, Knight and his colleagues etched four perpendicular channels a few micrometers deep and wide into a chip of silicon. The pressure from two side channels--filled with a solution of iodide--"squeezed" a fluorescent dye from both sides, squirting it into a stream as narrow as 50 nanometers. At such tiny scales, the iodide molecules mixed with the dye in less than 10 millionths of a second and used up only 25 billionths of a liter for 5 seconds' worth of data.
Researchers have already started doing experiments using the tiny mixing machine. Says William Eaton, a biophysical chemist with the National Institutes of Health, "This is potentially going to be one of the most powerful methods for studying protein folding." The quick speed and lack of turbulence will allow scientists to watch the first few microseconds of this complicated act.