Biosingularity

MIT creates 3D images of living cell

Posted on: August 15, 2007

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.

 Images of a cervical cancer cell Images of a cervical cancer cell taken using a new imaging technique developed at MIT. Figures a and b show 3D images of the cell. The green structures represent the nucleolus. The nucleus, not visible in these images, surrounds the nucleolus. The red areas are unidentified cell organelles. Figures c through h show the 2D images from which the 3D images were generated. In these images, each color represents a different range of refractive index. Image / Michael Feld laboratory, MIT“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.

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 two-dimensional 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.

“One key advantage of the new technique is that it can be used to study live cells without any preparation,” said Kamran Badizadegan, principal research scientist in the Spectroscopy Laboratory and assistant professor of pathology at Harvard Medical School, and one of the authors of the paper. With essentially all other 3D imaging techniques, the samples must be fixed with chemicals, frozen, stained with dyes, metallized or otherwise processed to provide detailed structural information.

“When you fix the cells, you can’t look at their movements, and when you add external contrast agents you can never be sure that you haven’t somehow interfered with normal cellular function,” said Badizadegan.

The current resolution of the new technique is about 500 nanometers, or billionths of a meter, but the team is working on improving the resolution. “We are confident that we can attain 150 nanometers, and perhaps higher resolution is possible,” Feld said. “We expect this new technique to serve as a complement to electron microscopy, which has a resolution of approximately 10 nanometers.”

Other authors on the paper are Christopher Fang-Yen, a former postdoctoral associate; graduate students Seungeun Oh and Niyom Lue; and Ramachandra Dasari, principal research scientist at the Spectroscopy Laboratory.

The research was conducted at MIT’s Laser Biomedical Research Center and funded by the National Institutes of Health and Hamamatsu Corporation.

Souce MIT Anne Trafton

About these ads

1 Response to "MIT creates 3D images of living cell"

[...] MIT Creates 3D Images of Living Cell – New ways to image cells are always extremely useful tools, and this one is no different. Check it out over at Biosingularity. [...]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 936 other followers

Follow me on Twitter

Medical Professional Database Award

 Doctor

Visitors Now

who's online

Blog Stats

  • 1,407,655 hits

Categories

Top Rated

Flickr Photos

moscow mime

The Mist Of Time

Oyster Fungi #100DaysofNature  Day 99

City Curves

Soar

Snowy Plover Malibu Lagoon 1606

Today's sunrise - Explored October 30, 2014 -  # 1

Blue Jay, Blue Snow (Explored no. 29)

The clown and the crocodile.

Anna Maria Island

More Photos

Maps

Networked blogs

Follow

Get every new post delivered to your Inbox.

Join 936 other followers

%d bloggers like this: