A high-resolution microscope built in Germany can capture three-dimensional images of proteins within tiny cellular organelles such as mitochondria.
Traditional fluorescence microscopes image a sample 'slice-by-slice' and then assemble those images into a three-dimensional picture. They usually handle slices more than 200 nanometres thick. Alexander Egner and Stefan Hell of the Max Planck Institute for Biophysical Chemistry in Göttingen and their co-workers have created a 'nanoscope' that improves resolution in three dimensions and can image slices measuring about 40 nanometres across.
The researchers used their invention to build up a picture of the distribution of a fluorescently labelled protein called Tom20 in mitochondria. They found that Tom20 forms clusters in the outer mitochondrial membrane.