Faster diagnosis with liquid crystals - within an hour

LAB-ON-A-CHIP may be more “chip-in-a-lab”. So, how does one make a lab that is truly a micro-chip? Assistant Professor Yang Kun Lin, Department of Chemical and Biomolecular Engineering, has the answer.

Researching liquid crystals for the past five years, one of Dr Yang’s latest developments is a cheaper and even more portable solution than the current lab-on-a-chip for medical diagnosis. It will definitely be faster as well, he says.
 
Current lab-on-a-chips though very small – still require a lab for further analysis. But Dr Yang says his method using liquid crystals is pocket-sized and can make diagnosis even in one’s own home, using nothing more than a drop of blood.

He said: “Most lab-on-chip devices still rely on fluorescence for detection, but fluorescence-based detection requires bulky instrumentation which negates the original purpose of miniaturisation.”

Currently, antibodies or biomarkers must be labelled with a fluorescent tag, and the results read off large, laser spectrometers. Dr Yang and his team have developed a method to read immunoassays using colours enabled by liquid crystals. So even laymen can read the results instead of skilled technicians required to interpret and analyse readings from the laser spectrometers.

“Although the original procedure required a microscope to read the different colours, the same results can be obtained using a single polarised filter and viewing the sample under sunlight,” said Dr Yang.

Th e tiny gadget can be even used by laymen in the convenience of their own homes. “Doctors can also perform fast screening of diseases, within one hour,” added Dr Yang., who has filed a patent for their solution.

Liquid crystals and molecular surface engineering

Dr Yang who did his PhD at the Georgia Institute of Technology, was from the National Taiwan University where he obtained the top 5 per cent Student Award. When he joined NUS in 2005, he led a new area in research, discovering new applications for liquid crystals.

A lot of what he is doing, he explains, is related to molecular surface engineering. “The technology behind liquid crystals lies in the treatment of the surface film which enables the surface to react correspondingly to the presence of chemicals we want to identify, be it a poisonous substance or biomarkers. The reaction will trigger off the liquid crystals to reorient, resulting in a change in colour,” said Dr Yang.

Liquid crystals are rod-shaped molecules which can diffuse freely like liquids (hence the name). They orient themselves under an electric field with the long-axis of the molecules pointing in the same direction. The passage of light through the crystals is determined by the crystals’ alignment. A change in their orientation or alignment would lead to a different colour being emitted.

The applications of molecular surfacing are numerous. “We may need to treat the surface of silicon chips used in drug delivery before insertion into the human body or prevent befouling or toxic effects. Bioscaffoldings would also require molecular surface engineering, to provide a surface that is suitable for their purpose,” said Dr Yang.

 
Dr Yang (extreme right) and his team have developed a method to read immunoassays using colours enabled by liquid crystals.