CAMBRIDGE, MA - A new imaging technique developed at MIT has allowed scientists to create the first 3D images of a living cell, using a method similar to the X-ray CT scans doctors use to see inside the body.
The technique, described in a paper published in the Aug. 12 online edition of Nature Methods, could be used to produce the most detailed images yet of what goes on inside a living cell without the help of fluorescent markers or other externally added contrast agents, said Michael Feld, director of MIT's George R. Harrison Spectroscopy Laboratory and a professor of physics.
Accomplishing this has been my dream, and a goal of our laboratory, for several years, said Feld, senior author of the paper. For the first time the functional activities of living cells can be studied in their native state.
Using the new technique, his team has created three-dimensional images of cervical cancer cells, showing internal cell structures. They've also imaged C. elegans, a small worm, as well as several other cell types.
The researchers based their technique on the same concept used to create three-dimensional CT (computed tomography) images of the human body, which allow doctors to diagnose and treat medical conditions. CT images are generated by combining a series of two-dimensional X-ray images taken as the X-ray source rotates around the object.
You can reconstruct a 3D representation of an object from multiple images taken from multiple directions, said Wonshik Choi, lead author of the paper and a Spectroscopy Laboratory postdoctoral associate.
Cells don't absorb much visible light, so the researchers instead created their images by taking advantage of a property known as refractive index. Every material has a well-defined refractive index, which is a measure of how much the speed of light is reduced as it passes through the material. The higher the index, the slower the light travels.