Biodefense roundupNanotechnology allows for rapid detection of viruses
Forget waiting anxiously for days for lab test results; a new nanotechnology allows for detection of dangerous viruses within seconds — something which patients will appreciate as much as homeland security and first responders eager to identify a bioterror attack sooner rather than later
Waiting a day or more to get lab results back from the doctor’s office is irritating, and in some cases dangerous (say, during a suspected bioterror attack). Fortunately, it may soon become a thing of a past. Using nanotechnology, a team of University of Georgia researchers has developed a diagnostic test which can detect viruses as diverse as influenza, HIV, and RSV in sixty seconds or less. Not only time is being saved — the technique could save lives by rapidly detecting a naturally occurring disease outbreak or bioterrorism attack. “It saves days to weeks,” said lead author Ralph Tripp, Georgia Research Alliance Eminent Scholar in Vaccine Development at the UGA College of Veterinary Medicine. “You could actually apply it to a person walking off a plane and know if they’re infected.”
The technique, called surface enhanced Raman spectroscopy (SERS), works by measuring the change in frequency of a near-infrared laser as it scatters off viral DNA or RNA. This change in frequency, named the Raman shift for the scientist who discovered it in 1928, is as distinct as a fingerprint. This phenomenon is well known, but Tripp explained that previous attempts to use Raman spectroscopy to diagnose viruses failed because the signal produced is inherently weak.
The solution was found by UGA physics professor Yiping Zhao and UGA chemistry professor Richard Dluhy, who experimented with several different metals and methods and found a way significantly to amplify the signal. Using a method they have patented, they place rows of silver nanorods 10,000 times finer than the width of a human hair on the glass slides that hold the sample. And, like someone positioning a TV antenna to get the best reception, they tried several angles until they found that the signal is best amplified when the nanorods are arranged at an 86-degree angle.
Tripp said the technique is so powerful that it has the potential to detect a single virus particle and can also discern virus subtypes and those with mutations such as gene insertions and deletions. This specificity makes it valuable as a diagnostic tool, but also as a means for epidemiologists to track where viruses originate from and how they change as they move through populations.
The researchers are developing the business model to make their findings commercially viable, and are seeking venture capital and exploring ways to mass produce the silver nanorods. Next year, they plan on moving their enterprise to the Georgia BioBusiness Center, a UGA incubator for startup bio-science companies.
-read more in Saratchandra Shanmukh et al., “Rapid and Sensitive Detection of Respiratory Virus Molecular Signatures Using a Silver Nanorod Array SERS Substrate, Nano Letters 6, no. 11 (November 2006): 2630-36; also see Yiping Zhao et al., “Silver Nanorod Arrays Can Distinguish Virus Strains” at SPIE Web site
