HZB researchers take detailed x-ray images of intact undyed cells
Berlin, Germany--Combining the use of x-rays with nanotomography has allowed researchers at Helmholtz-Zentrum Berlin (HZB) to image structures of the components of mammalian cells in three dimensions at a 30 nm resolution.
|FIGURE. A slice through the nucleus of a mouse adenocarcinoma cell is taken using X-ray nanotomography. It reveals the nucleolus (Nu) and the membrane channels running across the nucleus (NMC). Credit: HZB/Schneider.|
Berlin, Germany--Combining the use of x-rays with nanotomography has allowed researchers at Helmholtz-Zentrum Berlin (HZB) to image structures of the components of mammalian cells in three dimensions at a 30 nm resolution.1
The technique has a crucial advantage over the conventional transmission electron microscope (TEM) in that, for the first time, there is no need to chemically fix, stain, or cut cells to study them. Instead, whole living cells are fast-frozen and studied in their natural environment. The new method exploits the natural contrast between organic material and water to form an image of all cell structures, delivering an immediate 3D image.
With the high resolution achieved by their microscope, the researchers, in cooperation with colleagues of the National Cancer Institute in the USA, have reconstructed mouse adenocarcinoma cells in 3D, seeing features such as the double membrane of the cell nucleus, nuclear pores in the nuclear envelope, membrane channels in the nucleus, numerous invaginations of the inner mitochondrial membrane, and inclusions in cell organelles such as lysosomes. Such insights will be crucial for shedding light on inner-cellular processes: such as how viruses or nanoparticles penetrate into cells or into the nucleus.
The researchers achieved this high 3D resolution by illuminating the minute structures of a frozen-hydrated cell with partially coherent light generated by BESSY II, using a high-resolution condenser lens.
1. Gerd Schneider et al., Nature Methods, (DOI:10.1038/nmeth.1533).
Posted by John Wallace
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