By Kalwinder KaurAug 28 2012
Researchers have developed a super-sensor by attaching nanoscale gold spheres onto a microscopic bead of glass for detecting single samples of even the tiniest viruses.
The sensor is based on “whispering gallery mode,” a special behavior of light that got its name from renowned circular gallery in London-based St. Paul’s Cathedral, where a whisper near the wall will be echoed around the gallery. In the same way, the waves of light being transmitted will be revolving within a small glass bead, achieving resonation at a specific frequency. Similarly, when brought in contact to a sensor, a virus can transform the light’s resonant frequency.
Changes in frequency ranging from the size of viruses to that of influenza were detected using initial glass sphere. However, the sensitivity of the system was not sufficient to detect smaller substance such as the Polio virus.
By augmenting the surface of the glass with gold nanospheres, the researchers brought up to 70x improvements to the sensitivity of the device. As a result, “Plasmonic hot spots” were created. The light waves were paired with electron waves in these areas. In addition to identifying the existence of the MS2 virus, this hybrid sensor was found to be capable of determining the weight of the virus by calculating the precise frequency alteration of the light. With slight modifications, the sensor can detect single proteins like cancer markers that enter the blood prior to detection of cancer.
The results were released in the American Institute of Physics (AIP) journal Applied Physics Letters.
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