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Reed Hutchinson UCLA Photographic Services
Jeffrey I. Zink (left), professor of chemistry and biochemistry, and Thoi Nguyen, graduate student and lead author of a paper published in the Proceedings of the National Academy of Sciences |
research beat
Big plans for tiny device
By Stuart Wolpert
UCLA Today
In their drive to build artificial molecular tools and machines that can be used to manipulate materials that are more than 1,000 times smaller than the thickness of a human hair, UCLA chemists have come up with an amazing invention.
They’ve created the first nano valve. A micro-device smaller than a living cell, it can trap a single molecule and then release it.
How does the valve work?
“The valve is like a mechanical system that we can control like a water faucet,” said UCLA graduate student Thoi Nguyen, a team member and lead author of a paper published in the Proceedings of the National Academy of Sciences. “Trapping the molecule inside and shutting the valve tight was a challenge.” But Nguyen solved the problem, a feat that earned him the moniker “master nano plumber.”
What is the nano valve made of?
The valve is made up of special molecules called switchable rotaxane molecules designed by a team led by chemist Fraser Stoddart, director of the California NanoSystems Institute (CNSI). He holds UCLA’s Fred Kavli Chair in Nanosystems Sciences. The molecules are attached to a tiny piece of glass, which measures about 500 nanometers. The glass has an even tinier hole or pore in it only a few nanometers in size. “It’s big enough to let molecules in and out, but small enough so that the switchable rotaxane molecules can block the hole,” said Jeffrey I. Zink, professor of chemistry and biochemistry and a member of CNSI and the research team.
How do scientists control the valve?
The switchable rotaxane molecule has a moveable part that can go down and up, thus blocking and then unblocking the hole in the glass. Using the chemical power from a single electron, UCLA scientists can open the valve to let a single molecule in and then shut the valve. To tell whether the molecule is trapped, they use a luminescent molecule that can be tracked as it emits light.
How could such a valve be used in the future?
“A nano valve potentially could be used as a drug delivery system,” Zink said. In future research, scientists will see how large a hole they can block. They are optimistic that they may be able to trap larger molecules, such as enzymes. Perhaps someday a living cell might ingest a nano valve that carries a drug in the form of biomolecules inside. Could light energy then be used to release that drug to the cell? Stay tuned.
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