Rapid results

Scientists at the University of Twente, Netherlands, have developed an ultra sensitive sensor that can be used in a handheld device to quickly detect various viruses and measure their concentration.

The sensor, developed during the PhD project of Aurel Ymeti, could be used to quickly screen people at hospitals, airports and emergency clinics to control outbreaks of diseases such as SARS and the bird flu. All it would take is a tiny sample of saliva, blood, or other body fluid. Dr. Aurel Ymeti and others will present their results in February’s issue of Nano Letters.

The essential innovation in the technique reported in this paper is the combining of an integrated optics interferometric sensor with antibody-antigen recognition approaches to yield a very sensitive, very rapid test for virus detection. The technology can be miniaturized and mass-produced and has the potential to be developed into a handheld, point-of-care device.

Separately, researchers in the US have been awarded $8.1m to develop a diagnostic device to test for avian flu and potential bioterrorism agents.

The new integrated device the researchers are developing may allow cost effective, point-of-care diagnosis of these agents within one to two hours, according to principal investigator Kelly Henrickson, MD, professor of paediatrics and microbiology at the Medical College of Wisconsin, Milwaukee.

Dr Henrickson previously developed the Hexaplex diagnostic test, using specialised reagents and genetic data for simultaneous detection of the seven most common lower respiratory viruses, including several varieties of influenza. This technology is the basis for an array of products for physicians worldwide to rapidly detect the microbes responsible for a variety of illnesses such as aseptic meningitis, chicken pox and SARS.

‘Our laboratory has pioneered a flexible, rapid, sensitive and specific method of simultaneously detecting multiple pathogens,’ says Dr Henrickson. ‘We have recently developed two BioTplex assays that detect many category 'A' bioterrorism agents.

‘However, new amplified DNA detection and nucleic acid purification methods beyond those used in the Hexaplex diagnostic test allow for the development of a single 'point-of-care' device that may enhance the speed, flexibility, throughput, and cost effectiveness of multiplex assays.’

Infectious agents identified to pose the greatest potential threat include Variola major (smallpox), Bacillus anthracis (anthrax), Yersinia pestis (plague), Clostridium botulinum toxin (botulism), Francisella tularensis (tularaemia), and a group of RNA viruses that cause hemorrhagic fevers (VHFs).

Additional concern exists over bird-to-human spread of avian flu and the potential adaptation for human-to-human spread. Current diagnostic assays are directed to the common human isolates of influenza A, but no assay is available to detect all of the avian varieties of influenza A, said to Dr Henrickson.