July 13, 2004
CD ELISA Medical Test Achieves First Success

A test commonly done in medical testing and in research may some day be done more quickly and cheaply on the surface of compact discs.

COLUMBUS, Ohio – Ohio State University engineers and their colleagues have successfully automated a particular medical test on a compact disc (CD) for the first time -- and in a fraction of the normal time required using conventional equipment.

The ELISA biochemical test -- one of the most widely used clinical, food safety, and environmental tests -- normally takes hours or even days to perform manually. Using a specially designed CD, engineers performed the test automatically, and in only one hour.

The patent-pending technology involves mixing chemicals inside tiny wells carved into the CD surface. The spinning of the CD activates the tests.

In a recent issue of the journal Analytical Chemistry, the engineers report that the CD successfully detected a sample of rat antibody -- a standard laboratory test -- using only one-tenth the usual amount of chemicals.

This first demonstration paves the way for CDs to be used to quickly detect food-borne pathogens and toxins, said L. James Lee, professor of chemical and biomolecular engineering at Ohio State. The same technology could one day test for human maladies such as cancer and HIV, using a very small cell sample or a single drop of blood.

Lee estimated that the first commercial application of the concept is at least two years away.

“This study shows that the technology is very promising, but there are challenges to overcome,” he said. “We have been working on designing special valves and other features inside the CD, and better techniques for controlling the chemical reactions.”

“When we work on the micro-scale, we can perform tests faster and using less material, but the test also becomes very sensitive,” he explained. As chemicals flow through the narrow channels and reservoirs carved in the CD, interactions between individual molecules become very important, and these can affect the test results.

These scientists are working on automating the ELISA test which is a very widely used type of biological test.

ELISA, short for enzyme linked immunosorbent assay, is normally conducted in much larger reservoirs inside a microtiter plate -- a palm-sized plastic grid that resembles an ice cube tray.

Microtiter plates are standard equipment in chemical laboratories, and ELISA testing is a $10-billion-per-year industry. It is the most common test for HIV. Still, the test is tedious and labor-intensive, in part because of the difficulty in mixing chemicals thoroughly enough to get consistent results.

“Everyone working in the life sciences labs would fall in love with this revolutionary CD system for ELISA because it's easier, faster and cheaper to use,” said Shang-Tian Yang, professor of chemical and biomolecular engineering at Ohio State and collaborator on the project. Yang and Lee are founding a company to commercialize the CD technology. Until then, product development is being handled by Bioprocessing Innovative Company, Inc., a company in which Yang is a part owner.

Automated techniques that scale down the size of the devices that do the testing make tests easier, faster, and cheaper to do while at the same time making the tests more sensitive. This will speed up the rate of scientific progress while also lowering the costs of doing science. But it is also going to change the way medicine is done. Rather than taking one trip to the doctor to give blood and other samples with a follow-up trip to get the results the trend is going to be toward in-office testing. You will walk in to a doctor's office, the doctor will decide on what tests to do, and then you will get the tests done and then see the doctor again to review the results during the same office visit. This will save both time and money.

For more on the use of CDs to do biological and medical tests see my previous posts CD Will Simultaneously Test Concentrations Of Thousands Of Proteins and CD Player Turned Into Bioassay Molecule Detection Instrument.

Share |      Randall Parker, 2004 July 13 02:35 PM  Biotech Advance Rates

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