Upfront

Tapping cells for clues

In his role as a pediatrician, Manish Butte, MD, PhD, often will push and prod a young patient’s abdomen, feeling for abnormalities. Now Butte and his colleagues have engineered a highly sensitive probe that can “tap” on living cells in a lab dish and make detailed measurements of their stiffness. The work, described in November in ACS Nano, is a major advance in atomic force microscopy, which itself was invented at Stanford in 1986.

Butte and his colleagues use atomic force microscopy to measure the mechanical properties of cells in much the same way as a handyman taps along drywall, listening for pitch changes that indicate the presence of wooden studs. By coupling their new, small, cellular probe with a traditional one, the Stanford scientists are able to sense faster oscillations than by using conventional devices alone. The technology allows them to examine very soft cells for the first time without damaging their delicate exteriors, and to complete measurements in minutes rather than weeks.

Andrew Wang, PhD, a former Stanford postdoc who shares lead authorship of the study, says that practical applications of the device range from a basic scientific understanding of cellular structure to immunology and oncology. “Cancers,” he notes, “are often stiffer than normal, healthy tissues, and we can use that knowledge to diagnose disease. But first you have to have good data, which our device provides.” He already has used an early form of the probe in work on breast cancer specimens taken from mastectomies.

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