Yvonne Carts-Powell

X-raying life

In Uncategorized on April 27, 2010 at 5:10 pm


That image is a pair of yeast cells. It’s pretty. It is also pretty exciting for reasons that may not be obvious.

X-ray diffraction has, historically, been important because it was available when we didn’t have other methods for probing the structure of things. Back in the day, if you couldn’t see something with an optical microscope, x-ray imaging was a last recourse. A diffraction image taken by Rosalind Franklin and her doctoral student Raymond Gosling provided experimental evidence that DNA molecules take the shape of a double helix. Back then, one had to grow crystals of the material, and it had to be dry when you shot the x-rays at it.

We’ve come a long way since then: we have x-ray sources that can provide laser-like beams, and techniques like x-ray diffraction microscopy. With them, researchers have made three-dimensional images of whole cells in a watery environment, with resolutions of 40 to 60 nanometers. (The wavelength of blue light is about 400 nanometers — these images show details a hundredth the size of that.)

A press release from the Berkeley Lab today announces a lensless x-ray diffraction microscope with even finer (10-nm) resolution. This is the highest resolution ever obtained with this method for biological specimens. The process takes longer than the 40-nm techniques, but it indicates that full 3-D tomography of whole cells at equivalent resolution should be possible.

Read more about it here: Lensless Imaging of Whole Biological Cells with Soft X-Rays.

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