7 hours ago by Jacqueline Mitchell In a series of experiments over the last five years, Igor Sokolov used an atomic force microscope like the one at left to look for physical differences between cancer cells and healthy cells. Credit: Alonso Nichols

As a young physicist in the former Soviet Union, Igor Sokolov studied the biggest of the bigthe entire universe. Now, as a professor of mechanical engineering at Tufts, he's focused on the tiny, the nano. By zooming inway, way inSokolov and his colleagues study everything from bacteria to beetles down to the nanoscale level. Now he's turned a fresh eye on one of medicine's oldest problems: cancer.

Sokolov's instrument of choice is the atomic force microscope (AFM), which uses its minuscule finger-like probe to measure tiny forces at a very small scale, "pretty much between individual atoms," he says. He first came across this technology as a graduate student studying the origins of the universe more than 20 years ago, about the time the AFM was invented. He used it to look for evidence of theoretical elementary particles. When Sokolov didn't find any, his work helped put those ideas to bed.

Soon Sokolov turned the instrument toward more earthly concerns. By 1994, as a member of the microbiology department at the University of Toronto, he was among the first to use AFM to study bacteria. Zooming in on a probiotic bacterium used to make Swiss cheese, Sokolov revealed a never-before-documented process by which the cell repairs its surface after sustaining chemical damage.

The experiment also demonstrated AFM's ability to detect mechanical changes in living cells at unprecedented resolutionsomething that would be useful in Sokolov's later work. "That was the beginning of my love of biomedical applications," says Sokolov, who also has appointments in the departments of biomedical engineering and physics.

Closer Look at Cancer

More recently, Sokolov and his colleagues have used atomic force microscopy on some of the most mysterious cells of allmalignant ones. Most existing diagnostic tools use the cells' chemical footprint to identify cancer. In a series of experiments over the last five years, he looked for physical differences between cancer cells and healthy cells that could help physicians diagnose cancer earlier and more accurately. Early detection substantially increases patients' chances of survival.

He and his collaborators have had some promising results in preliminary studies using cervical and bladder cancer cells"cancers where you can harvest cells without biopsiesvery un-invasive methods," he points out.

In 2009, Sokolov and his colleagues at Clarkson University in New York studied healthy and diseased cells that were virtually identical, biochemically speaking. Searching for some physical or mechanical difference that could help distinguish the two types of cells, the researchers found that the surface coat surrounding cancer cellswhat Sokolov calls the pericellular brush layerwas markedly different from that of the normal ones.

"That was definitely new," he says, noting that similar results were recently published by researchers using more traditional biochemical methods. "The authors called those findings the result of the change of paradigm of looking at cancer."

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Nano scale research could yield better ways to identify and track malignant cells