Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

When proteins, antibodies and other biological molecules kiss, a new kind of biosensor can tell

21.09.2007
A new and deceptively simple technique has been developed by chemists at Vanderbilt University that can measure the interactions between free-floating, unlabeled biological molecules including proteins, sugars, antibodies, DNA and RNA.

That is precisely the kind of capability needed to capitalize on the new avenues of research that have been opened up by the 15-year-plus effort to sequence the human genome. DNA is the blueprint of all living creatures.

But, just as the blueprint of a building is much simpler than the actual structure, so too DNA is far simpler than the myriad of molecules that make up living bodies. As a result, scientists need powerful new methods to study the actual behavior of all these molecules, particularly how they work together.

The new method is called back-scattering interferometry (BSI). By shining a red laser like those used in barcode scanners into a microscopic, liquid-filled chamber where two kinds of molecules are mixed, the instrument can measure the strength with which they react, even when the interactions are extremely weak. In fact, the researchers have demonstrated that it is sensitive enough to detect the process of protein folding, they report in the Sept. 21, 2007 issue of the journal Science.

... more about:
»Bornhop »DNA »Interaction »measure

“Molecular interactions are the very heart of biology,” says Professor of Chemistry Darryl J. Bornhop, who headed the 12-year development process. “Pharmaceuticals depend on reactions between proteins and small molecules or between pairs of proteins or between interactions between RNA and DNA or pairs of DNA molecules. So the ability to measure how that happens is very advantageous.”

The members of the Bornhop research team are post doctoral students Joey Latham and Dmitry Markov; graduate student Amanda Kussrow; Henrik Sorenson, who is now at the Risø National Laboratory in Denmark; and Senior Research Associate Richard Jones.

The method represents an entirely new application of interferometry, a powerful technique that combines light from multiple sources to make precise measurements. Interferometry is used in everything from astronomy to holography to geodetic surveys to inertial navigation.

The equipment required for the new biosensor is surprisingly modest: a helium-neon laser like those used in grocery store scanners, a mirror, a CCD detector like those used in digital cameras and a special glass microfluidic chip. The chip contains a channel about one fiftieth the size of a human hair. There is a “Y” at one end that allows the researchers to inject two solutions simultaneously, each containing a different kind of molecule. It is followed by a serpentine section that mixes the two.

Finally, there is a straight observation section where the interactions are measured. An unfocused laser beam is directed through the channel at this point. The beam is reflected back and forth inside the channel about 100 times. Each time the light beam strikes the channel some of the light is transmitted back up to the mirror where it is directed to the detector. There it forms a line of alternating light and dark spots called an interference pattern.

It turns out that the interference pattern is very sensitive to what the molecules are doing. If the molecules begin sticking together, for example, the pattern begins to shift. The stronger the binding force between the molecules, the larger the shift. This allows the system to measure interaction forces that vary a million-fold. That includes the entire range of binding forces found in living systems.

The reason the system works so well is still something of a mystery. The researchers know that it responds to minute changes in the index of refraction, which is a measure of how fast the light travels through the liquid in the chamber compared to its speed in a vacuum. They suspect that it has to do with the rearrangement in the water molecules that cover the surface of the proteins: When two proteins react they squeeze the water molecules out of the area where they bind together. This displacement changes the density of the liquid slightly which, in turn, alters its index of refraction.

BSI has some potential cost advantages compared to current techniques. “The price of the equipment required for BSI is modest and the entire system could easily be miniaturized and integrated with ‘lab on a chip’ systems,” says Bornhop. It is also easy to adapt for high-throughput operation: processing hundreds or thousands of different samples at the same time, he says.

Vanderbilt has applied for and received two patents on the process and has several other patents pending. The university has issued an exclusive license to develop the technology to Molecular Sensing, Inc. Bornhop is one of the founders of the start-up and serves as its chief scientist. The company plans on completing a prototype system this fall.

Vanderbilt University is a private research university of approximately 6,300 undergraduates and 4,600 graduate and professional students. Founded in 1873, the University comprises 10 schools, a public policy institute, a distinguished medical center and The Freedom Forum First Amendment Center. Vanderbilt, ranked as one of the nation’s top universities, offers undergraduate programs in the liberal arts and sciences, engineering, music, education and human development, and a full range of graduate and professional degrees.

David F. Salisbury | Vanderbilt University
Further information:
http://www.vanderbilt.edu
http://www.vanderbilt.edu/News

Further reports about: Bornhop DNA Interaction measure

More articles from Life Sciences:

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

nachricht Transforming plant cells from generalists to specialists
07.12.2016 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>