August 15, 2007 – MIT recently developed a new imaging technique that reportedly allows 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.
Using the new technique, the research team created 3D images of cervical cancer cells, showing internal cell structures. The team 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 3D CT (computed tomography) images of the human body, which allow doctors to diagnose and treat medical conditions.
The researchers made their measurements using a technique known as interferometry, in which a light wave passing through a cell is compared with a reference wave that doesn't pass through it. A 2D image containing information about refractive index is thus obtained. To create a 3D image, the researchers combined 100 2D images taken from different angles. The resulting images are essentially 3D maps of the refractive index of the cell's organelles. The entire process took about 10 seconds, but the researchers recently reduced this time to 0.1 seconds.
The team's image of a cervical cancer cell reveals the cell nucleus, the nucleolus and a number of smaller organelles in the cytoplasm. The researchers are currently in the process of better characterizing these organelles by combining the technique with fluorescence microscopy and other techniques.
For more information: web.mit.edu