RNA virus infections are often diagnosed using polymerase chain reaction (PCR) tests, however technical requirements are high and sample preparation time can be long. For RNA viruses such as Ebola and Marburg, which could be used as bio-warfare agents, rapid diagnosis is a necessity. Researchers at Boston University have developed a new biosensor that directly detects live viruses from biological media with little to no sample preparation. From the press release:
The new biosensor is the first to detect intact viruses by exploiting plasmonic nanohole arrays (PNAs), or arrays of apertures with diameters of about 250 to 350 nanometers on metallic films, that 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 effective refractive index in the close vicinity of 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 the concentration of the virus in the solution.
“Unlike PCR and ELISA approaches, our method does not require enzymatic amplification of a signal or fluorescent tagging of a product, so samples can be read immediately following pathogen binding,” said Altug. Ahmet Yanik, Altug’s research associate who conducted the experiments, added, “Our platform can detect not only the presence of the intact viruses in the analyzed samples, but also indicate the intensity of the infection process.”
The researchers are now working on a highly portable version of their biosensor platform using microfluidic technology designed for use in the field with minimal human interference. They plan to subject the platform to initial tests on samples containing Ebola, Marburg and other hemorrhagic fever viruses in the U.S., followed by additional tests in resource-limited countries in Africa where outbreaks of hemorrhagic fever occur.
The researchers have shown to be able to reliably detect hemorrhagic fever virus surrogates (i.e. for the Ebola virus) and poxviruses (such as monkeypox or smallpox). Results have been published in the November 5 online edition of Nano Letters.
Press release: Novel Biosensor Could Enable Rapid, Point-of-Care Virus Detection…
Study abstract: An Optofluidic Nanoplasmonic Biosensor for Direct Detection of Live Viruses from Biological Media…