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Benjamin Zeskind set out to reveal quantitative details about structures inside a living cell and ended up with a new deep-ultraviolet microscope.

“Traditional biological images are mainly colorful pictures of cells and tissues that are limited to telling you if something is present in the cell,” says Zeskind. “We wanted to understand better the structures in cells, how they move around and change, so we needed an inherent way of measuring how much of a macromolecule is present in the cell or an organelle.”

“When we started the project, people thought we were crazy,” he adds.

Now a Harvard Business School student, Zeskind was a biological engineering graduate student in Whitehead Member Paul Matsudaira’s lab when he led the development of the deep-ultraviolet microscope, which is described in the July issue of Nature Methods.

These images of a mouse macrophage, taken at 280-nanometer ultraviolet wavelengths, show how the mass of proteins (top) and the mass of nucleic acids (bottom) are distributed. As expected, nucleic acid is concentrated in the cell nucleus while proteins are distributed more widely throughout the cell. Images: Benjamin Zeskind

Using the microscope at a deep-ultraviolet wavelength of 280 nanometers along with computational software Zeskind developed, researchers can analyze image intensity to determine the mass of proteins and nucleic acids in a cell. That gives a sense of how the structures are distributed and how they move and change over time.

“The nucleus of a cancer cell has a very different structure from the nucleus of a normal cell,” Zeskind says. “This microscope helps us better understand the structures in cells and their dynamics.” Down the road, he suggests, the technique might lead to advances such as very early diagnosis of cancer.

UV LEDs aid imaging

The microscope relies on deep-ultraviolet light-emitting diodes, a recent technology spin-off from the military that can emit light at a precisely specified wavelength and be switched on and off rapidly. Zeskind took the glass lenses out of a conventional light microscope and installed quartz lenses (bought used on eBay) to handle deep-ultraviolet wavelengths.

At those shorter wavelengths, the UV microscope can provide more quantitative information as well as improve the spatial resolution over that of a traditional light microscope.

The UV diodes also reduce the ultraviolet exposure and don’t kill the cell, which has been the major challenge of deep-ultraviolet imaging. The microscope can image cell division and migration for as long as 45 minutes with minimal light-induced damage to the cell. Deep-ultraviolet technology also eliminates the need in traditional visible light microscopy to label a cell with fluorescent dyes, which stress the cell.

“When Confucius said a picture is worth a thousand words, he put a picture in the context of something else, the number of words,” says Matsudaira, who is director of the Whitehead-MIT BioImaging Center. “This microscope can give us a picture of a cell so we can now ask how much protein is in it. It allows us to think in a different way.”