Posted September 17th, 2012
Scientists are developing an ultrasensitive biosensor into a point-of-care diagnostic platform that they claim can detect and size the smallest virus particle, or potentially a single protein molecule, in a patient’s blood, urine, or saliva sample within minutes. The Whispering Gallery-Mode biosensor developed by researchers at the Polytechnic Institute of New York University (NYU-Poly) derives its name from the Whispering Gallery in the dome of St. Paul’s Cathedral in London, the acoustics of which allows a single whisper to be heard throughout the gallery space.
The amplified biosensor developed by Stephen Arnold, Ph.D., and colleagues effectively measures changes in resonance frequency in a glass sphere as it is contacted by a virus particle or a protein. Experiments reported by Professor Arnold and colleagues showed the platform is capable of detecting MS2, the smallest RNA virus particle known to man, which has a mass of only about 1% that of an influenza virus.
The basic technology underpinning the sensor is thus: Light from a tunable laser is guided down a fiber-optic cable, and its intensity is measured by a detector at the distal end. A small glass sphere is contacted with the fiber, and this diverts the path of the light and causes it to orbit within the sphere. This change is recorded as a resonant dip in transmission through the fiber.