X-ray crystallography routinely yields the structures of proteins and other biomolecules with 0.1-nm resolution. But how does one take a similarly detailed look at something far bigger—a chromosome, say, or a cell nucleus? Such objects don’t crystallize because no two individuals have the same shape. And at a micron or so in size, they’re too thick for electron microscopy. Electrons either get stuck in the object or scatter too many times on their way out to form a clear image.
X rays, of course, pass through whole animals, not just single cells. For the past decade or so, groups around the world have been developing a technique called x-ray diffraction microscopy for imaging single, uncrystallized samples.
The first biological application of XDM appeared in 2003. Jianwei Miao, who’s now at UCLA, and his collaborators obtained two-dimensional images of single Escherichia coli bacteria with 30-nm resolution. 1 To boost the scattered...
