Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cornell’s tiny, vibrating paddle oscillator senses the mass of a virus

05.11.2004


By using a device only six-millionths of a meter long, researchers at Cornell University have been able to detect the presence of as few as a half-dozen viruses -- and they believe the device is sensitive enough to notice just one.



The research could lead to simple detectors capable of differentiating between a wide variety of pathogens,i ncluding viruses, bacteria and toxic organic chemicals. The experiment, an extension of earlier work in which similar devices were used to detect the mass of a single bacterium, is reported in a paper, "Virus detection using nanoelectromechanical devices," in the September 27, 2004, issue ofApplied Physics Letters by Cornell research associate Rob Ilic of the Cornell NanoScale Facility (CNF), Yanou Yang, a Cornell graduate student in biomedical engineering, and Harold Craighead, Cornell professor of applied and engineering physics. The work was done with the assistance of Michael Shuler, Cornell professor of chemical and biological engineering, and microbiologist Gary Blissard of the Boyce Thompson Institute for Plant Research on the Cornell campus.

At CNF, the researchers created arrays of tiny silicon paddles from 6 to 10 micrometers (millionths of a meter) long, half a micrometer wide, and about 150 nanometers (billionths of a meter) thick, with a one-micrometer square pad at the end. Think of a tiny fly-swatter mounted by its handle like a diving board. A large array of paddles were mounted on a piezoelectric crystal that can be made to vibrate at frequencies on the order of 5 to 10 megaHertz (mHz). The experimenters then varied the frequency of vibration of the crystal. When it matched the paddles’ resonant frequency, the paddles began to vibrate, as measured by focusing a laser on the paddles and noting the change in reflected light, a process called optical interferometry.


The natural resonant frequency at which something vibrates depends on, among other things, its mass. A thick, heavy guitar string, for example, vibrates at a lower tone than a thin, light one. A single one of these silicon paddle weighs about 1.2 picograms, and vibrates at frequencies in the neighborhood of 10 megaHertz. The virus used in the experiment weighs about 1.5 femtograms. (A picogram is 1/1,000,000,000,000th of a gram, and a femtogram is 1/1000th of a picogram.) Adding just a few virus particles to a paddle turns out to be enough to change its resonant frequency by about 10 kiloHertz (kHz), which is easily observable.

To trap viruses, the researchers coated the paddles with antibodies specific to Autographa californica nuclear polyhedrosis virus, a nonpathogenic insect baculovirus widely used in research. The paddle arrays were then bathed in a solution containing the virus, causing virus particles to adhere to the antibodies. Because air damps the vibration and greatly reduces the "Q," or selectivity, of the system, the treated paddles were placed in a vacuum for testing. From the frequency shift of about 10 kHz the researchers calculated that an average of about six virus particles had adhered to each paddle. It might be possible, the researchers say, to demonstrate detection of single particles by further diluting the virus solution. The system also can differentiate between various virus concentrations, they say.

As expected, the smallest paddles were the most sensitive. The researchers calculated that the minimum detectable mass for a six-micrometer paddle would be .41 attograms (an attogram is 1/1000th of a femtogram.) This opens the possibility that the method could be used to detect individual organic molecules, such as DNA or proteins.

Other members of the Craighead Research Group at Cornell have experimented with "nanofluidics," creating microscopic channels on silicon chips through which organic molecules can be transported, separated or even counted. Ilic speculates that a simple field detector for pathogens -- the much-heralded "laboratory on a chip" -- could be built by combining a paddle oscillator detector with a nanofluidic system that would bathe the paddles in a suspect sample, then automatically evacuate the chamber to a vacuum for testing. Arrays of paddles coated with various antibodies could allow testing for a wide variety of pathogens at the same time.

Bill Steele | EurekAlert!
Further information:
http://www.cornell.edu
http://www.hgc.cornell.edu

More articles from Life Sciences:

nachricht Warming ponds could accelerate climate change
21.02.2017 | University of Exeter

nachricht An alternative to opioids? Compound from marine snail is potent pain reliever
21.02.2017 | University of Utah

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Start codons in DNA may be more numerous than previously thought

21.02.2017 | Life Sciences

An alternative to opioids? Compound from marine snail is potent pain reliever

21.02.2017 | Life Sciences

Warming ponds could accelerate climate change

21.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>