Published on May 13, 2005

Studying materials and substances at the molecular level has helped researchers at the Faculty of Science at Mahidol University develop a new method of detecting diseases on a minute scale beyond the reach of even the most powerful microscopes.

The research team can now detect malaria and leptospirosis by using molecules of conjugated polymer. Instead of using a conventional disease culture, which takes several weeks to yield a result, researcher Tanakorn Osotchan said the new method would shorten the time needed to detect disease to just a few minutes.

The team developed its own molecular engineering method to engineer molecules of conjugated polymer to detect disease in the lab. “We have to study the conjugated polymer at the molecular level to understand its properties and then rearrange it by adding some substances to make the molecule fit our purposes,” Tanakorn said.

This process is a kind of nanotechnology, which Tanakorn said allows researchers to manipulate materials or substances atom by atom, molecule by molecule.

The project also received support from the National Metal and Materials Technology Centre and the National Nanotechnology Centre.

Tanakorn said the team chose conjugated polymer molecules as they offered electrical-conductivity properties. When a current is passed through them, violet, red or yellow light is released, to identify the extent of any disease in a blood sample.

The team also designed a technique to put conjugated polymer molecules on a transparent electrode so that electricity will force the molecules to release light as required. Tanakorn said the team researched a coating technique to put the molecules on transparent electrode film and they found that the coating must be only one monolayer thick.

One monolayer means that the team has to coat the transparent film with just a single layer of molecules so that when it comes to disease detection, it will give accurate results.

Meanwhile, he said the molecules themselves had to be designed to have two surfaces. The first is for connecting to water and this surface is attached to the electrode. The second surface is water-resistant and is used for catching the disease. “Once we have a transparent electrode coated with molecules, we can, for example, run a blood sample through the film for disease detection,” Tanakorn said. This process requires further equipment to measure the change of light and colour when the molecules catch the disease.

“The machine shows changes in the amount of light and this information is sent to a computer system so researchers can identify how strong the disease is. This information will be of great help to doctors,” he said.

By using molecular engineering, he added, the team could improve the disease-detection process and make it much faster.

“We can now detect a disease a few minutes after receiving a blood sample - much faster than the disease-culture method, which takes several weeks,” he added. “The new method can detect disease in much smaller samples of blood, so growing a culture is no longer necessary for the purposes of detection.”

The method is now reliable at the lab-scale level. The team also plans to improve the development of molecules and the coating technique to make the coated transparent electrode film reusable 100 times. Now, the film can be reused only 10 times.

Tanakorn said that as a result of this experience with molecular engineering, the team could make further developments on new molecules from other substances to use for other purposes.

“For example, we could use this technique to develop detection systems to indicate food quality or fruit maturity as well as an odor-detection system which could analyse a patient’s breath to check for symptoms of influenza or lung disease. It could even search for bombs,” he added.

pongpen@nationgroup.com

Pongpen Sutharoj

The Nation

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