Featured Research

from universities, journals, and other organizations

USC Robot Moves Molecule-Size Particles Into Precise Locations

Date:
March 17, 1998
Source:
University Of Southern California
Summary:
In very small but hugely significant print, an interdisciplinary team of scientists at the University of Southern California's Laboratory for Molecular Robotics has boldly placed USC on the nanotechnology frontier. The USC scientists used a uniquely programmed atomic force microscope as a robot to push gold particles 15 nanometers in size into precise locations on a poly lysine-coated mica surface, spelling out the letters "USC."

In very small but hugely significant print, an interdisciplinary team of scientists at the University of Southern California's Laboratory for Molecular Robotics has boldly placed USC on the nanotechnology frontier.

Nanotechnology is the development of mechanical devices on a scale of nanometers; a nanometer is a billionth of a meter. The USC scientists used a uniquely programmed atomic force microscope as a robot to push gold particles 15 nanometers in size into precise locations on a poly lysine-coated mica surface, spelling out the letters "USC."

The gold particles are about 500 times smaller than a red blood cell and are comparable in size to some molecules.

Ari Requicha, Ph.D., professor of computer science and electrical engineering/systems and leader of the USC team, says that the next frontier in miniaturization will be nanoelectromechanical systems (NEMS).

"Control over the structure of matter at the atomic or molecular scale will undoubtedly trigger a major revolution in man-made artifacts," Dr. Requicha says.

NEMS will be extremely small and fast, saving space and energy. Applications could include cell repair, or ultrastrong materials derived from molecularly perfect prototypes, or compact disc machines with a thousand times more capacity than current models.

Sales of currently used microelectromechanical systems (MEMS) devices such as pressure sensors and accelerometers number in the millions, but MEMS will soon bump against the size limits of the semiconductor technology used to fabricate them.

The USC team seeks to master the construction of NEMS by precisely positioning and assembling molecular- sized components. The work is done at room temperature and normal air pressure, and even in liquids, in contrast to some other projects that have used very low temperatures and ultrahigh vacuums.

For now the scientists are using commercially available colloidal gold spheres, five to 30 nanometers in size. The balls are thinly coated with gold chloride, making them slightly negatively charged to prevent clumping.

Requicha explains that at the nanometer level, material no longer behaves in a classical manner. The scientists exploit the physical forces in play at the nanoscale with the atomic force microscope (AFM).

The microscope has a sharp silicon tip and can sense the atomic forces between the tip and the sample. Several piezoelectric actuators move the tip to and from the sample and laterally to scan the surface with enough resolution to detect atomic-scale features.

When the tip is brought very close to the sample, say a nanometer or less, interatomic repulsive forces keep it from penetrating. The same forces will also push a gold ball across the mica substrate, in which case the AFM is acting as a robot.

Commercial AFMs are designed for imaging, not manipulation, and so the USC team had to write software to direct the manipulation operation -- no minor task. With a s tandard AFM that cannot act as a sensor and as a manipulator at the same time, the AFM operator would have to fly blind using an image of the surface scanned previously. However, instrument errors and thermal expansion and contraction cause the gold balls to drift with respect to the AFM between the time they are scanned and the time they are to be moved.

The team has overcome these problems and now moves nanoparticles to precise locations reliably, making increasingly elaborate two-dimensional patterns with the gold balls. The team has begun experimenting with organic compounds called thiols, which could be used to connect the balls into wires and more complex structures.

Requicha sees the assembly of three-dimensional structures as an important challenge and said the invention of molecular grippers for picking up and placing nanoscale objects is high on the research agenda.

"We can definitely do things that haven't been done," Requicha said. "But these are small steps toward the production of useful NEMS. We still have a long way to go. The first potential applications we are considering are nanoCDs, digital storage devices analogous to compact discs but with very high densities. In the long run, one of our main goals is to build nanomachines for biomedical applications."

Other members of the team are Bruce E. Koel, Ph.D., professor of chemistry and materials science; Anupam Madhukar, Ph.D., professor of materials science and physics; Peter Will, Ph.D., division leader at the Information Sciences Institute and research professor of industrial and systems engineering; and postdoctoral researchers and graduate and undergraduate students in computer science, materials science and chemistry.

The research was supported by a grant from the Z.A. Kaprielian Technology Innovation Fund.

Research papers on USC's nanotechnology project can be found on the Laboratory for Molecular Robotics' website at: http://alicudi.usc.edu:80/~lmr


Story Source:

The above story is based on materials provided by University Of Southern California. Note: Materials may be edited for content and length.


Cite This Page:

University Of Southern California. "USC Robot Moves Molecule-Size Particles Into Precise Locations." ScienceDaily. ScienceDaily, 17 March 1998. <www.sciencedaily.com/releases/1998/03/980317071611.htm>.
University Of Southern California. (1998, March 17). USC Robot Moves Molecule-Size Particles Into Precise Locations. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/1998/03/980317071611.htm
University Of Southern California. "USC Robot Moves Molecule-Size Particles Into Precise Locations." ScienceDaily. www.sciencedaily.com/releases/1998/03/980317071611.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com
U.K. To Allow Driverless Cars On Public Roads

U.K. To Allow Driverless Cars On Public Roads

Newsy (July 30, 2014) Driverless cars could soon become a staple on U.K. city streets, as they're set to be introduced to a few cities in 2015. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins