Observing Cells by Leaving them Alone

3D image of breast cancer cells

It’s one of cell biology’s Catch-22s: To observe a cell’s behavior, researchers often have to expose it to a dye or some other chemical. However, dyes change a cell’s behavior, making the observations less reliable. But now, researchers at the University of Illinois have developed a technique that provides 3-D images of live cells without introducing dyes or any other agents. This new approach should have wide application, and could be particularly useful when viewing stem cells.

Traditionally, scientists have exposed cells to chemicals, ultraviolet light or lasers to observe their inner workings. However, this new imaging technique, called white-light diffraction tomography (WDT), provides striking 3-D images without interfering with cell function.

The images look a lot like the cross-sections you see in MRI or CT scans, except on a much smaller scale. These cellular images can be moved around, rotated and, of course, magnified. This gives researchers the opportunity to see both the forest and the trees. In other words, they can image the whole cell or take a deep dive into a cell’s internal structure, such as the nucleus, with high resolution.

Even better, because WDT doesn’t alter the cell, scientists can observe it throughout its life cycle. This could provide a wealth of information about cancer cells, such as how they react to specific treatments. It could also follow stem cells as they differentiate or change from one intermediate cell type to another on their way to becoming full-fledged neurons, heart muscle cells or other tissues. These observations could provide important new insights into how stem cells evolve.

One of the most exciting things about WDT is that it doesn’t require any exotic, new (and very expensive) technology. The University of Illinois team intentionally built this approach using phase contrast microscopes, a common piece of lab equipment that converts invisible light variations into visible changes in brightness.

The best part? Researchers can watch different cellular components interacting in real time. They will be able to conduct detailed studies on cellular growth, look at how cells react to specific treatments and measure how different parts of the cell move around without having to wonder if the imaging method is tarnishing their results.

We are funding research into this area too, including work being done by Dr. Steve Conolly at U.C. Berkeley to develop a magnetic particle imaging device, which produces images of a much greater sensitivity and brightness compared to a standard MRI. Dr. Conolly talked about his work in one of our Spotlight on Disease videos.

Josh Baxt