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The GW Hatchet


The GW Hatchet

Serving the GW Community since 1904

The GW Hatchet

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GW developing one-of-a-kind million-dollar microscope

Never before has a torpedo fish’s stunning mechanism for seeking its prey simultaneously caught the attention of biologists, chemists and physicists. But soon the secrets of this unique sea creature – and the complexities of life’s molecular structures – could be revealed on the fourth floor of Corcoran Hall.

Akos Vertes, professor of chemistry, biochemistry and molecular biology, as well as collaborators from GW’s other science departments, are using a $1.5 million grant awarded by the W.M. Keck Foundation in July 2004 to develop the first in vivo microscope able to scan the cells of living tissue without disrupting the original sample.

“It’s a one-of-a-kind, home-built microscope that we’re working on,” said Vertes, who is also co-director of the GW Institute of Proteomics Technology and Applications.

The interdisciplinary team is led by Vertes and Mark Reeves, associate professor of physics; Fatah Kashanchi, associate professor of biochemistry; and Eric Hoffman, director of the Research Center for Genetic Medicine at The Children’s National Medical Center.

Hoffman said the microscope is not yet built, but he anticipated it could be completed within two years. He said the device’s potential to study the interaction of proteins in the cell and cellular environment of living tissue makes it cutting-edge science.

“(The microscope) does all the right things,” said Columbian College of Arts and Sciences Dean William Frawley. “It brings together faculty for a common research focus. It transcends departmental boundaries. It provides the basis for substantial external funding for undergraduate and graduate research, and, most importantly, it provides new science.”

The human genome, the complete sequence of DNA in humans, was mapped by scientists in 2002. Now, the even more complex structures of proteins are forcing scientists to come together to study the next frontier of biology.

“Proteins are molecules that regulate and carry out the function of every cell and, ultimately, direct its way of living,” said Vertes, who also supervises undergraduate and graduate students working on the project.

“They’re major players. If you take deoxyribonucleic acid out of a cell and put it in a tube by itself, it can’t do anything. You need proteins to carry out life processes.”

The torpedo fish’s unique ability to electrocute its prey will allow scientists to better understand the molecules that link nerve and muscle signals, leading to improved understanding of how similar molecules may interact in humans. Vertes explained that his collaborators at the children’s center are working on preliminary analyses of the torpedo fish’s unique tissue to gain a knowledge base before launching the microscope’s first investigation.

The researchers hope to use the microscope’s high spatial resolution, or better clarity, to determine the location and concentration of specific proteins within the tissue, which, Vertes said, is a major leap in science.

As of now, it is impossible to gain such specific information about the location and types of proteins in the cell and cellular environment as a result of sample preparation techniques, such as adding a die or fluorescent proteins, which could affect the sample’s natural conditions.

The new microscope would have no need for sample preparation. In fact, the water contents of a cell (about two-thirds the total fluid content) will aid in the examination. An infrared laser, similar to those used in eye surgery, will deposit light energy into water that helps to eject tiny charged proteins, about one one-thousandth of the size of the cell. The proteins move into a detector that will help identify known proteins in the sample.

The microscope will use a 100-nm-tip optical fiber, a rod that directs laser light, to shoot the light neatly onto a live sample and its surroundings. The unique process will allow scientists to capture the image of proteins in their natural environment.

Each protein ejects from the cell at a unique speed, which indicates the protein’s mass. Ultimately, a computer program helps match the identity of the fragments to a known protein inside a database.

Typically, a laser is farther away from a sample. In the case of GW’s new microscope, the fiber is only nanometers away from the sample, preventing light rays from diffracting and ensuring a sharper image.

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