A miniature biosensor developed by Professor Hatice Altug's team of researchers at Boston University is the first to detect intact viruses by exploiting plasmonic nanohole arrays. The size of a quarter, the biosensor can quickly detect live viruses from biological media and measure the intensity of the infection process. It is described in the November 5, 2010 online edition of Nano Letters. Unlike PCR and ELISA approaches, the new method requires no enzymatic signal amplification or fluorescent tagging, so samples can be read immediately following pathogen binding with little or no preparation. In collaboration with the U.S. Army Medical Research Institute for Infectious Diseases, the BU team has demonstrated reliable detection of hemorrhagic fever virus surrogates (for the Ebola virus) and pox viruses (such as smallpox) in ordinary biological laboratory settings.
Metallic film plasmonic nanohole arrays, with apertures of 200 to 350 nm in diameter, transmit light more strongly at certain wavelengths. When a live virus in a sample solution, such as blood or serum, binds to the sensor surface, the refractive index in close proximity to the sensor changes, causing a detectable shift in the resonance frequency of the light transmitted through the nanoholes. The magnitude of that shift reveals the presence and concentration of the virus in the solution.
The researchers are now working on a version of the platform designed for use in the field with minimal training.