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Boston U. and Columbia Nanoscience Researchers Attack Viruses

by Editor1 last modified November 29, 2010 - 11:16

Boston University researchers have developed a portable diagnostic device that can quickly identify dangerous viruses with very small blood samples. Meanwhile, researchers at Columbia use nanoscale science to identify how these viruses trigger disease.

Boston U. and Columbia Nanoscience Researchers Attack Viruses

BU’s new biosensor is the first to detect intact viruses by exploiting plasmonic nanohole arrays (apertures with diameters of 200 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 surface of the biosensor, the refractive index in the close vicinity of the sensor changes. This change in turn causes 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, explained Assistant Professor Hatice Altug of the Boston University College of Engineering. Altug co-led the BU team with Assistant Professor John Connor of BU’s School of Medicine.

The team demonstrated reliable detection of hemorrhagic fever virus surrogates (i.e. for the Ebola virus) and pox viruses (such as monkeypox or smallpox) in ordinary biological laboratory settings.

The nanoscale approach aims to make virus detection much faster, more portable and even takes a lot of cost out of manufacturing devices. "By enabling ultra-portable and fast detection, our technology can directly impact the course of our reaction against bio-terrorism threats and dramatically improve our capability to confine viral outbreaks," Altug said.

Traditional virus diagnostic tools are effective, but require significant infrastructure and sample preparation time. The BU team’s biosensor can detects live viruses directly from biological media – virtually eliminating time needed to prepare samples.

BU’s biosensor focuses viruses that use RNA to replicate, including hemorrhagic fever viruses such as Ebola and Marburg.

The biosensor project was partly funded through BU’s Photonics Center and the U.S. Army Research Laboratory, and was achieved in collaboration with the U.S. Army Medical Research Institute for Infectious Diseases. The breakthrough is detailed in the Nov. 5 online edition of Nano Letters.

"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.

The team is now working on a highly portable version of their biosensor platform using microfluidic technology designed for use in the field with minimal training.

BU’s work comes as another research team at Columbia U. has discovered a key mechanism by which the Filoviruses, Ebola and Marburg, cause disease, and reported it has identified an amino acid sequence in Filoviruses that results in the rapid depression of immunological response. Using this information, researchers can begin to develop new drugs to stop these devastating diseases.

The team is comprised of researchers at the Greene Infectious Disease Laboratory at Columbia University's Mailman School of Public Health, the Centers for Disease Control and Prevention, and the Caribbean Primate Research Center.

Filoviruses are associated with outbreaks of fatal hemorrhagic fever in sub-Saharan Africa. Today, there is no cure or approved vaccine for either Marburg or Ebola virus, and it causes immunosuppression quick after infection, allowing viruses to reproduce.

"The identification of this new mechanism for immunosuppression is anticipated to lead to new drugs for intervention in filoviral hemorrhagic fevers of humans and apes,” said Dr. W. Ian Lipkin, director of the Greene Infectious Disease Laboratory at the Mailman School's Department of Epidemiology and professor of Epidemiology, Neurology, and Pathology at Columbia University.

In the study, researchers describe a series of amino acids in Ebola and Marburg viruses that resemble proteins in retroviruses known to suppress the immune system. By targeting these amino acids, new drugs could disrupt the ability of these viruses to shut down immune systems and make them vulnerable to the body's natural defenses.