Coated with gold and sandwiched between tiny electrodes, specially designed polymer beads provide a cheap, disposable device for detecting disease, University of Delaware scientists say.
A prototype, "gold-on-plastic" biosensor, protected by a provisional patent and described in the May 25 issue of Langmuir, also may prove useful for analyzing food and environmental samples.
With a detection region about the size of a living cell, multiple biosensors can be placed on a single chip, reports Eric W. Kaler, the University's Elizabeth Inez Kelley Professor of Chemical Engineering.
"Our biosensor detects targeted molecules and rapidly generates an objective, electrical readout," says Kaler, chairperson of the UD Department of Chemical Engineering. "We believe it may eventually be sensitive enough to detect as few as 30 targeted molecules in a sample."
The new technology represents an alternative to a popular, but more indirect and subjective, laboratory procedure known as the latex agglutination test (LAT), according to Kaler and his coinventor, Research Assistant Prof. Orlin D. Velev.
The widely used LAT procedure, first developed in 1956, makes it possible to screen bodily fluids for a host of diseases--from Lyme disease and tuberculosis to human immunodeficiency virus (HIV), Velev explains. Latex agglutination tests also detect antibiotics in foods and pregnancy-related hormones in urine. The tests use latex coated with specific antigens, or foreign particles, to detect antibodies through a biochemical "clumping" process called agglutination, Velev says.
While the agglutination approach is "fast and robust," Velev says, it also requires a relatively large sample. Moreover, he says, "The resulting optical readout may be complex, and it is subject to interpretation by a clinician."
Simple, automated and robust electronic biosensors may be a better option for
many types of tests, Velev says. The UD invention requires only a microsco
'"/>
Contact: Ginger Pinholster
gingpin@udel.edu
302-831-6408
University of Delaware
8-Jul-1999