Genes linked to cancer could be easier to detect with liquid lasers

Jan 31, 2012
Researchers have developed a highly sensitive technique based on laser emission for differentiating a target DNA strand from strands that contain single base mismatches. Laser emission is used to amplify the small difference in signals that are generated by the different strands after they bind with a molecular beacon. The conversion is similar to analog-to-digital. Credit: Christopher Burke

Using a liquid laser, University of Michigan researchers have developed a better way to detect the slight genetic mutations that might predispose a person to a particular type of cancer or other diseases.

Their results are published in the current edition of the German journal .

This work could advance understanding of the of diseases. It also has applications in personalized medicine, which aims to target drugs and other therapies to individual patients based on a thorough knowledge of their .

The researchers say their technique works much better than the current approach, which uses fluorescent dye and other to find and bind to mutated . When a patrol molecule catches one of these rogues, it emits a fluorescent beacon. This might sound like a solid system, but it's not perfect. The patrol molecules tend to bind to healthy DNA as well, giving off a background glow that is only slightly dimmer than a positive signal.

"Sometimes, we can fail to see the difference," said Xudong Fan, an associate professor in the Department of Biomedical Engineering and principal investigator on the project. "If you cannot see the difference in signals, you could misdiagnose. The patient may have the mutated gene, but you wouldn't detect it."

In the conventional fluorescence technique, the signal from mutated DNA might be only a few tenths of a percent higher than the . With Fan's new approach it's hundreds of times brighter.

Using this liquid laser, University of Michigan professor Xudong Fan has developed a highly sensitive technique for identifying mutated DNA that differs from healthy DNA by a single base. The fine white horizontal line is the capillary cavity that enables the laser to amplify the intrinsic difference in the light signals from healthy and mutated DNA. Credit: Nicole Casal Moore

"We found a clever way to amplify the intrinsic difference in the signals," Fan said.

He did it with a bit of backtracking.

Liquid lasers, discovered in the late '60s, amplify light by passing it through a dye, rather than a crystal, as solid-state lasers do. Fan, who works at the intersection of biomedical engineering and , has been developing them for the past five years. In his unique set-up, the signal is amplified in a glass capillary called a "ring resonator cavity."

Last year, Fan and his research group found that they could employ DNA (the blueprints for life that reside in all cells) to modulate a liquid laser, or turn it on and off. His group is one of just a few in the world to accomplish this, Fan said. At the time, they didn't have a practical application in mind. Then they had an epiphany.

"We thought, 'Let's look at the laser output. Can we see what's causing the different outputs and use it to detect differences in the DNA?'" Fan said. "I had an intuition, and it turns out the output difference was huge."

The journal editors named this a "hot paper" that "advances knowledge in a rapidly evolving field of high current interest."

Explore further: Researchers have developed a diagnostic device to make portable health care possible

More information: The paper is titled "Distinguishing DNA by Analog-to-Digital-like Conversion by Using Optofluidic Lasers." The research was funded by the National Science Foundation. The first author is Yuze Sun, a doctoral student in the Department of Biomedical Engineering. The university is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.

Related Stories

New Device Shines Light on Disease-Causing Molecules

Jul 08, 2008

If a doctor could identify a single molecule indicating the presence of a disease before the disease has a chance to harm the patient, the practice of medicine and the health of patients would be greatly improved. That’s ...

Scientists closer to new cancer detection method

Nov 29, 2005

University of Florida researchers say they are a step closer to a technique to easily detect a wide variety of cancers before symptoms become apparent. The findings, currently online in the Proceedings of the National Ac ...

Researchers turn up brightness on fluorescent probes

Aug 09, 2010

Researchers from Carnegie Mellon University's Molecular Biosensor and Imaging Center (MBIC) are turning up the brightness on a group of fluorescent probes called fluoromodules that are used to monitor biological ...

Revealing Photographs of DNA

May 10, 2007

Ultrasensitive genetic detection methods could revolutionize the diagnosis and treatment of diseases. However, all the techniques until now have been far too technically demanding for broad application. Munich researchers ...

Recommended for you

Chemical biologists find new halogenation enzyme

8 hours ago

Molecules containing carbon-halogen bonds are produced naturally across all kingdoms of life and constitute a large family of natural products with a broad range of biological activities. The presence of halogen substituents ...

Protein secrets of Ebola virus

14 hours ago

The current Ebola virus outbreak in West Africa, which has claimed more than 2000 lives, has highlighted the need for a deeper understanding of the molecular biology of the virus that could be critical in ...

Protein courtship revealed through chemist's lens

14 hours ago

Staying clear of diseases requires that the proteins in our cells cooperate with one another. But, it has been a well-guarded secret how tens of thousands of different proteins find the correct dancing partners ...

Decoding 'sweet codes' that determine protein fates

16 hours ago

We often experience difficulties in identifying the accurate shape of dynamic and fluctuating objects. This is especially the case in the nanoscale world of biomolecules. The research group lead by Professor Koichi Kato of ...

Science to the rescue of art

Sep 14, 2014

Vincent van Gogh's "Sunflowers" are losing their yellow cheer and the unsettling apricot horizon in Edvard Munch's "The Scream" is turning a dull ivory.

User comments : 0