Optics used to track single cell’s growth

U. ILLINOIS (US) — Researchers are using optics to measure a basic biological process: the growth of single cells. It’s a process that has been difficult to quantify using other methods.

Engineers from the Beckman Institute at the University of Illinois recently reported in the Proceedings of the National Academy of Sciences using small changes in the optical properties of  single living cells to measure their growth.

“Determining the growth patterns of single cells,” the researchers write, “offers answers to some of the most elusive questions in contemporary cell biology: how cell growth is regulated and how cell size distributions are maintained.”

This image illustrating the Spatial Light Interference Microscopy (SLIM) technique is a rendering of dry mass maps with CG light passing through them. (Credit: Beckman Institute’s Visualization Laboratory)

Gabriel Popescu of the electrical and computer engineering department and his collaborators were able to demonstrate a newly developed optical interferometric technique, known as spatial light interference microscopy (SLIM), that can “measure the cell dry mass of many individual adherent cells in various conditions, over spatial scales from micrometers to millimeters, temporal scales ranging from seconds to days, and cell types ranging from bacteria to mammalian cells,” the researchers write.

Mir says SLIM is capable of measuring mass with a sensitivity of one femtogram, or one thousandth of the mass of a cubic micron of water.

“By using a fluorescence reporter in conjunction with this novel optical technique, we were also able to differentiate how the cells regulate their growth in different stages of their lifecycle,” he says. “Aside from the basic science interest, this technology could have broader implications in understanding the effects of cancer treatments and other forms of therapy on the fundamental process of cell growth.”

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