Featured Research

from universities, journals, and other organizations

Golden Scales: Nanoscale Mass Sensor Can Be Used To Weigh Individual Atoms And Molecules

Date:
July 29, 2008
Source:
DOE/Lawrence Berkeley National Laboratory
Summary:
There's a new "gold standard" in the sensitivity of weighing scales. Using the same technology with which they created the world's first fully functional nanotube radio, Berkeley Lab researchers have fashioned a nanoelectromechanical system that can function as a scale sensitive enough to measure the weight of a single atom of gold. This NEMS scale could prove especially useful for measuring the mass of proteins and other molecules which don't fare well in mass spectrometry.

A double-walled carbon nanotube NEMS has been used to measure the mass of a single atom of gold. Atoms landing on the tube change the tube's resonant frequency in proportion to the mass of the atoms, much like what happens when a diver hits a springboard.
Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory

There’s a new “gold standard” in the sensitivity of weighing scales. Using the same technology with which they created the world’s first fully functional nanotube radio, researchers with Berkeley Lab and the University of California (UC) at Berkeley have fashioned a nanoelectromechanical system (NEMS) that can function as a scale sensitive enough to measure the mass of a single atom of gold.

Alex Zettl, a physicist who holds joint appointments with Berkeley Lab's Materials Sciences Division (MSD) and UC Berkeley’s Physics Department, where he is the director of the Center of Integrated Nanomechanical Systems, led this research. Working with him were members of his research group, Kenneth Jensen and Kwanpyo Kim.

“For the past 15 years or so, the holy grail of NEMS has been to push them to a small enough size with high enough sensitivity so that they might resolve the mass of a single molecule or even single atom,” Zettl said. “This has been a challenge even at cryogenic temperatures where reduced thermal noise improves the sensitivity. We have achieved sub-single-atom resolution at room temperature!”

The new NEMS mass sensor consists of a single carbon nanotube that is double-walled to provide uniform electrical properties and increased rigidity. One tip of the carbon nanotube is free and the other tip is anchored to an electrode in close proximity to a counter-electrode. A DC voltage source, such as from a battery or a solar cell array, is connected to the electrodes. Applying a DC bias creates a negative electrical charge on the free tip of the nanotube. An additional radio frequency wave "tickles" the nanotube, causing it to vibrate at a characteristic “flexural” resonance frequency.

When an atom or molecule is deposited onto the carbon nanotube, the tube’s resonant frequency changes in proportion to the mass of the atom or molecule, much like the added mass of a diver changes the flexural resonance frequency of a diving board. Measuring this change in frequency reveals the mass of the impinging atom or molecule.

"Getting nanotubes to vibrate is fairly easy," said Jensen. "The difficult part is detecting those small vibrations. We accomplished this by field-emitting, or spraying, electrons from the tip of the nanotube and detecting the resulting electrical current."

Using their NEMS mass sensor, Zettl, Jensen and Kim were able to weigh individual gold atoms and measure masses as small as two fifths that of a gold atom at room temperature and in just a little more than one second of time. A gold atom has a mass of 3.25 x 10-25kilograms, which means that there are about 3 million million million million gold atoms in a single kilogram.

While there have been other NEMS that function as mass sensors before, most of these previous devices were fashioned from silicon, and none had achieved the magical single-atom resolution at room temperature. The carbon nanotube mass sensor of Zettl’s group is a thousand times smaller by volume than typical NEMS resonators – measuring only about a billionth of a meter in diameter and 200 billionths of a meter in length.

“Carbon nanotubes are the ideal material for this purpose and their small size makes them sensitive enough to resolve single atoms even at room temperature,” Jensen said.

While scientists already have the ability to measure the mass of individual atoms through a complex technique known as mass spectrometry, this new carbon nanotube NEMS mass sensor offers some distinct advantages and opens the door to new possibilities, as Jensen explained.

“Unlike mass spectrometry, our device does not require the ionization of neutral atoms or molecules that can destroy samples such as proteins. Also unlike mass spectrometers, our carbon nanotube mass sensor becomes more sensitive at higher mass ranges, which makes it more suitable for measuring large biomolecules like DNA. Finally, our device is small enough so that, in time, it could be incorporated onto a chip.”

Zettl, Jensen and Kim described their NEMS mass sensor in a paper published in the journal Nature Nanotechnology, entitled: “An atomic-resolution nanomechanical mass sensor.” This research was supported by the U.S. Department of Energy’s Office of Science, Basic Energy Sciences Program’s Materials Sciences and Engineering Division, and by the National Science Foundation within the Center of Integrated Nanomechanical Systems.


Story Source:

The above story is based on materials provided by DOE/Lawrence Berkeley National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jensen et al. An atomic-resolution nanomechanical mass sensor. Nature Nanotechnology, 2008; DOI: 10.1038/nnano.2008.200

Cite This Page:

DOE/Lawrence Berkeley National Laboratory. "Golden Scales: Nanoscale Mass Sensor Can Be Used To Weigh Individual Atoms And Molecules." ScienceDaily. ScienceDaily, 29 July 2008. <www.sciencedaily.com/releases/2008/07/080728192940.htm>.
DOE/Lawrence Berkeley National Laboratory. (2008, July 29). Golden Scales: Nanoscale Mass Sensor Can Be Used To Weigh Individual Atoms And Molecules. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2008/07/080728192940.htm
DOE/Lawrence Berkeley National Laboratory. "Golden Scales: Nanoscale Mass Sensor Can Be Used To Weigh Individual Atoms And Molecules." ScienceDaily. www.sciencedaily.com/releases/2008/07/080728192940.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
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