ENGINEERING PROFESSOR AT UNM DEVELOPS DEVICE FOR EARLY DETECTION OF HANTAVIRUS AND OTHER BACTERIA

August 19, 2003

ENGINEERING PROFESSOR AT UNM DEVELOPS DEVICE FOR EARLY DETECTION OF HANTAVIRUS AND OTHER BACTERIA
Sensor could save lives by expediting detection of various life-threatening viruses

Researchers in the Department of Chemical and Nuclear Engineering at the UNM School of Engineering have developed a small, portable device that can aid in the early detection of viruses, specifically the hantavirus, in rural areas where sophisticated medical diagnostic capabilities are absent and thereby increasing chances of saving someone’s life. The device, an electrochemical immunosensor, can detect the presence of the virus in approximately 20 minutes.

Ebtisam Wilkins, numerous doctorate students, post-doctoral fellows and also undergraduates working in Wilkins’ lab, have worked collectively to create the device in collaboration with Professors Fred Koster and Brian Hjelle from the UNM School of Medicine, and Terry Yates, vice provost for Research and biology professor. The electronic shop in the UNM Chemistry Department also assisted later on during development.
“We’ve been developing a really portable device, funded by the National Science Foundation, that can detect the Hantavirus and can be modified to detect the presence of other bacteria such as salmonella and E. coli,” said Wilkins. “The basic principle is performed based on antibodies that bind specifically to viruses and bacteria.”

Conventional immunoassay techniques are based on the principle of molecular recognition of a target sample by corresponding antibodies. It involves a laboratory technique that makes use of the binding between an antigen and its homologous antibody in order to identify and quantify the specific antigen or antibody in a sample.

The assay technique, which is being developed and tested for use in the field by UNM researchers,
is a qualitative or quantitative analysis of a substance to determine its components. The basic principles
of alternative assay methods are the same as immunoassay techniques which includes the registration of antigen-antibody interaction. The attraction of an electrochemical detection of labeled immunospecies for immunoassay is connected to a high sensitivity and versatility of the technique.

The immunosensor is based on conductive particles with high surface area, which are used for the electrode material modified by immunoagents and are arranged for flow-injection analysis. The best way to reduce the time of the immunoassay procedure, and detection of potentially harmful viruses or diseases, is to increase the area-to-volume ratio of the solid or immunoabsorbent to liquid phases. An immunoabsorbent is an antibody (or antigen) used to remove specific antigen (or antibody) from solution or suspension.

The conductivity of conductive materials permits the use of conductive-based immunosorbents as electrode materials for amperometric measuring of enzyme levels. Amperometric measuring is a type of chemical analysis involving electrical currents. The analysis used in research and testing has been the ‘sandwich’ assay scheme, where genetic recombination has taken place in an organism or cell.

The detection procedure used a recombinant protein for Hantavirus that was immobilized on the surface of the immunosorbent. Target analyte captured by the immunosorbent at the first stage of incubation interacts with the peroxidase labeled antihuman antibodies at the second stage of incubation. The detection of peroxidase (enzymes that catalyze the oxidation of a substance by a peroxide) label was conducted amperometrically by electroreduction of iodine formed as a product of peroxidase catalyzed reaction. In turn, the time it takes to determine the presence of the Hantavirus is cut to approximately 22 minutes.

Other applications for the immunosensor can include perishable food tests, such as meat or milk, environmental, veterinarian and medical diagnostics such as hepatitis and AIDs. Tests of this nature are currently too time consuming from the time a sample is cultured in the laboratory to the point where the bacteria multiply and can be detected.

“In an age where the West Nile virus, AIDS, SARS and other viruses are widespread, a defense against the presence of these infectious viruses or bacteria, could be accomplished by detecting them before they spread,” said Wilkins. “That is why a sampling of air or environmental liquid samples are important and needed on a real-time basis for detection before infection takes place.”

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