Three-dimensional visualization of a human chromosome using coherent X-ray diffraction.

Coherent x-ray diffraction microscopy is a lensless phase-contrast imaging technique with high image contrast. Although electron tomography allows intensive study of the three-dimensional structure of cellular organelles, it has inherent difficulty with thick objects. X rays have the unique benefit of allowing noninvasive analysis of thicker objects and high spatial resolution. We observed an unstained human chromosome using coherent x-ray diffraction. The reconstructed images in two or three dimensions show an axial structure, which has not been observed under unstained conditions.