Tiny Diamonds Levitate in Wild Physics Experiment

ORIGINAL: LiveScience
By Laura Poppick, Staff Writer

August 14, 2013

Researchers have used lasers to levitate extremely small particles in the past, such as individual atoms, but this is the first time that anyone has ever levitated a nanodiamond. Credit: J. Adam Fenster/University of Rochester.

In quite an eerie feat, physicists have floated microscopic diamonds in midair using laser beams.

Researchers have already used lasers to levitate extremely small particles, such as individual atoms, but this is the first time that the technique has worked on a nanodiamond, which, in this case, measures just 100 nanometers (3.9 x 10-8 inches) across, or more than 1,000 times thinner than a fingernail.

In the new study, the physicists from the University of Rochester relied on the fact that a laser beam, which is made up of photons, creates a tiny force that usually can't be felt. [Wacky Physics: The Coolest Little Particles in Nature]

"If we turn on a light or open a door and feel the sun, we don't feel this push or pull," study researcher Nick Vamivakas said in a video released by the university. "But it turns out that if you focus a laser down with a lens to a very small region of space, it can actually pull on microscopic, nanoscopic particles."

To force the tiny diamonds to float, Vamivakas and his colleagues focused a pair of lasers toward a clear vacuum chamber and then sprayed the diamonds into the chamber using an aerosol dispenser. The diamonds gravitated toward the light, and some eventually levitated in a stable position.

Sometimes, the levitation occurred within just a couple of minutes, while other times, the process took a bit longer.

"Other times, I can be here for half an hour before any diamond gets caught," Levi Neukirch, a graduate student at the University of Rochester who was involved in the study, said in a statement. "Once a diamond wanders into the trap, we can hold it for hours."

The team hopes the findings will have applications in quantum computing and, more theoretically, help explain how friction operates on extremely small scales.

"The position of the crystal in the trap is a very sensitive probe of forces in its environment," Vamivakas said in the university video. "The reason this is important is, as technology continues to shrink down to these length scales, we need to understand how the environment will interact with the devices that we are making."

The team plans to continue its experiments in order to better understand the physical behavior of the crystals, which could help address other basic unanswered questions in physics.

The levitation experiment is detailed this week in the journal Optics Letters.

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No magic show: Real-world levitation to inspire better pharmaceuticals

ORIGINAL: Argonne National Lab

BY JARED SAGOFF 
SEPTEMBER 12, 2012

It’s not a magic trick and it’s not sleight of hand – scientists really are using levitation to improve the drug development process, eventually yielding more effective pharmaceuticals with fewer side effects.

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have discovered a way to use sound waves to levitate individual droplets of solutions containing different pharmaceuticals. While the connection between levitation and drug development may not be immediately apparent, a special relationship emerges at the molecular level.

At the molecular level, pharmaceutical structures fall into one of two categories: amorphous or crystalline. Amorphous drugs typically are more efficiently taken up by the body than their crystalline cousins; this is because amorphous drugs are both more highly soluble and have a higher bioavailability, suggesting that a lower dose can produce the desired effect.

“One of the biggest challenges when it comes to drug development is in reducing the amount of the drug needed to attain the therapeutic benefit, whatever it is,” said Argonne X-ray physicist Chris Benmore, who led the study.

“Most drugs on the market are crystalline – they don’t get fully absorbed by the body and thus we aren’t getting the most efficient use out of them,” added Yash Vaishnav, Argonne Senior Manager for Intellectual Property Development and Commercialization.

Getting pharmaceuticals from solution into an amorphous state, however, is no easy task. If the solution evaporates while it is in contact with part of a vessel, it is far more likely to solidify in its crystalline form. “It’s almost as if these substances want to find a way to become crystalline,” Benmore said. 

In order to avoid this problem, Benmore needed to find a way to evaporate a solution without it touching anything. Because liquids conform to the shape of their containers, this was a nearly impossible requirement -- so difficult, in fact, that Benmore had to turn to an acoustic levitator, a piece of equipment originally developed for NASA to simulate microgravity conditions.

Levitation or “containerless processing” can form pristine samples that can be probed in situ with the high-energy X-ray beam at Argonne’s Advanced Photon Source. “This allows amorphization of the drug to be studied while it is being processed,” said Rick Weber, who works on the project team at the synchrotron.

The acoustic levitator uses two small speakers to generate sound waves at frequencies slightly above the audible range – roughly 22 kilohertz. When the top and bottom speakers are precisely aligned, they create two sets of sound waves that perfectly interfere with each other, setting up a phenomenon known as a standing wave.

At certain points along a standing wave, known as nodes, there is no net transfer of energy at all. Because the acoustic pressure from the sound waves is sufficient to cancel the effect of gravity, light objects are able to levitate when placed at the nodes.

Although only small quantities of a drug can currently be “amorphized” using this technique, it remains a powerful analytical tool for understanding the conditions that make for the best amorphous preparation, Vaishnav explained.

Argonne researchers have already investigated more than a dozen different pharmaceuticals, and the laboratory’s Technology Development & Commercialization Division is currently pursuing a patent for the method. Technology Development & Commercialization is also interested in partnering with the pharmaceutical industry to develop the technology further as well as to license it for commercial development.

After adapting the technology for drug research, the Argonne scientists teamed up with Professors Stephen Byrn and Lynne Taylor at the Department of Industrial and Physical Pharmacy at Purdue University and Jeffery Yarger of the Department of Chemistry and Biochemistry at Arizona State University. The group is now working on identifying which drugs the levitation instrumentation will impact most strongly.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy'sOffice of Science.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.