The smallest of all worlds

It has been in operation at the university for a few days now: Europe's first commercially available light microscope with a resolution of less than 50 nanometres. It can be used to investigate processes in living cells.

The best way to understand the power of the super microscope is to make a comparison: a human hair is around 70,000 nanometres thick. And the microscope has a resolution of less than 50 nanometres.

Scientists led by neurobiologists Prof. Dr Reto Weiler and Prof. Dr Henrik Mouritsen at the Research Centre Neurosensory Science will be working with the device in future. The purchase of the 880,000 euro device was made possible by funds provided in equal parts by the Lower Saxony Ministry of Science (MWK) and the German Research Foundation (DFG). The device is a gated STED (Stimulated Emission Depletion) microscope from Leica Microsystems.

"The money for cutting-edge technology is well invested in Oldenburg. A light microscope like this is currently only available in very few places around the world. The scientists and students at the University of Oldenburg are the first in Europe to be able to use such a high-tech device," says Lower Saxony's Science Minister Prof. Dr Johanna Wanka.

"The microscope enables the scientists at the Research Centre Neurosensory Science to conduct research at the highest methodological level," explains University President Prof. Dr Babette Simon. It sustainably strengthens Oldenburg as a centre of science and the international competitiveness of Oldenburg's neurosensorics.

The extremely high resolution of the microscope makes it possible to uncover the finest cellular details. This is made possible by the gated STED technology, which goes back to the Göttingen physicist Prof Dr Stefan Hell. It overcomes the resolution limit that the wavelength of light generally sets for optical instruments by utilising the principle of fluorescence. The specimen is scanned by a detector and combined into an image on the computer. This latest generation of light microscopy significantly improves the precision and contrasts that were previously possible.

The scientists in Weiler's Neurobiology working group want to use the new microscope to advance their retina research. This will initially focus on the localisation of electrical synapses in the retina, which play a key role in the adaptation of vision to different levels of brightness. The researchers are also analysing the transport and binding processes of cell-specific proteins in the neuronal network of the retina.

Unlike an electron microscope, the new device can be used to observe processes in living cells, explains Mouritsen, who is investigating the navigation of migratory birds with his research group. The scientists want to use the super microscope to clarify how the birds' magnetic compass works, which is most likely located in the chryptochrome - a light receptor in the nerve cells of the eyes.