Detecting viruses with nanotech-aided spectroscopy

Detecting viral infections normally requires that blood or tissue samples be taken from suspected carriers and analysed in pathology labs. This takes considerable time, but such delays may soon be a thing of the past owing to a novel diagnostic test developed by researchers at the University of Georgia, and detailed in a recent issue of Nano Letters (subscription required).

Led by Ralph Tripp, a Georgia Research Alliance Eminent Scholar in infectious diseases, the team claim that their technique could save lives by rapidly detecting naturally occurring disease outbreaks or bioterrorist activity. It could even be applied to passengers walking off a plane if they are suspected of being infected.

The technique, called Surface Enhanced Raman Spectroscopy, works by measuring the shift in frequency of a near-infrared laser beam as it scatters from viral DNA. Raman spectroscopy is well-established in chemistry, and used routinely to identify molecular constituents in prepared samples.

The problem with using Raman spectroscopy as a medical diagnostic is that the scattered signal is extremely weak. What Tripp and his UGA colleagues Yiping Zhao and Richard Dluhy have done is to amplify the signal by placing rows of silver nanorods on the glass slides that hold the sample.

Distinct spectral bands have so far been identified for a number of common human viruses, and Tripp hopes to expand this into an online encyclopaedia of Raman viral signatures. With a signal amplification factor of 100 million, the test can in theory detect a single virus particle present in a sample.

“I strongly believe that our technology represents the advent of the next generation of pathogen detection, i.e. the next level beyond polymerase chain reaction,” says Tripp, who with colleagues is now preparing a business plan to exploit the technique, and is in negotiations with a west coast venture capital company.

Article first published in Nanomaterials News. © 2006 Pira International – all rights reserved.