Nanotechnology
improves food safety by detecting prions
Source of Article: http://www.tmcnet.com/usubmit/2008/10/29/3744281.htm
(Farm Talk Newspaper
(Parsons, Kan.)
Via Acquire Media NewsEdge) Oct. 29--Mad cow
disease is a fatal neurodegenerative condition in cattle that is related to
the human form of a disease that has caused the deaths of nearly 200 people
worldwide. Currently, testing for this disease in cattle is a lengthy process
that only occasionally results in a correct diagnosis.
With funding from USDA's Cooperative State Research, Education, and Extension
Service (CSREES) National Research Initiative (NRI), scientists in New York
created a new device that may provide a faster, easier, and more reliable way
to test for mad cow disease, also known as bovine spongiform encephalopathy
(BSE).
This new tool targets prions, which are the cause
of BSE. Prions are abnormally structured proteins
that convert normal proteins into an abnormal form. Prions
are responsible for forms of the neurodegenerative diseases, such as BSE in
cattle, scrapie in sheep, and Creutzfeldt-Jakob
disease in humans. If often takes years before the symptoms arise that
indicate the disease is present.
There are no rapid tests
available to test for the presence of prions in
cattle.
The only test currently available for BSE involves multiple steps, requires
sacrificing an animal host, and takes time. The process requires infecting an
animal with a patient's blood. Then, after a several month incubation period,
the animal is sacrificed and scientists look for prions
during the animal's autopsy. This method produces the correct diagnosis only
31 percent of the time.
A better method of prion detection is necessary to
allay public fears, ensure the safety of the nation's food supply, and enhance
international trade.
Harold Craighead and colleagues at Cornell
University have
developed nanoscale resonators, which are tiny
devices that function like tuning forks by changing pitch with increased
mass.
Craighead's group, in collaboration with Richard Montagna at Innovative Biotechnologies International,
Inc., modeled the device after a similar idea used to detect bacterial
pathogens. When prions bind to the resonator's
silicon sensor, it changes the vibrational resonant
frequency of the device. In experimental trials, the sensor detected prions at concentrations as low as two nanograms per milliliter, the smallest levels measured to
date.
Currently, the resonator only detects prions in a
saline solution. Efforts are now underway to use the resonator to detect prions in more complex solutions, such as blood.
"The real challenge is going to be to build an automated device that can
take blood from a cow in the field and give a rapid response as to whether prions are present," Craighead said. "At the
moment we only test cows when they fall over, but that is a late stage of the
disease. It would be ideal to test cows a lot earlier. Resonators could be
one path to doing this."
Scientists hope the new device will soon be used to detect prions in food items to ensure food safety and quality
for the national food supply.
CSREES funded this research project through the NRI Nanoscale
Science and Engineering for Agriculture and Food Systems program. Through
federal funding and leadership for research, education and Extension
programs, CSREES focuses on investing in science and solving critical issues
impacting people's daily lives and the nation's future. For more information,
visit www.csrees.usda.gov.
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