Nobel Prize in Chemistry for fluorescence microscopy
This month, the Nobel Prize in Chemistry was awarded to two physicists and a physical chemist. The Americans Eric Betzig and William Moerner and the Romanian-German Stefan Hell managed to circumnavigate the classical limitations of light microscopes and this enabled microscopy to develop into nanoscopy. As a result of this, scientists can now study processes in living systems in far greater detail than was previously possible.
Classical microscopy is limited by the wavelength of the light used. Details smaller than half of that wavelength (typically 250 nanometres) cannot be imaged with a classical microscope. As a result of this it is technically impossible to study viruses, proteins and individual molecules using a classical microscope. It is possible using an electron microscope but then living structures are often destroyed.
The three Nobel Prize winners each independently contributed to the use of fluorescence techniques with which the classical boundary of microscopy could be broken and that have brought us nanoscopy. Thanks to their discoveries it is now possible, for example, to follow proteins during the development of the embryo or to image how molecules make connections in the brain.
Physicist Stefan Hell, who is currently scientific director at the Max Planck Institute in Germany, invented the STED microscope in 2000 (STED stands for stimulated emission depletion). Using two laser beams, a STED microscope first generates fluorescence and subsequently extinguishes this everywhere except in a volume several nanometres in size. The microscope moves that volume nanometre by nanometre and by doing this it can scan the sample with superresolution.
Experimental physicist Betzig and physical chemist Moerner each worked separately on the microscopy of molecules. They managed to switch the fluorescence of molecules on and off and to subsequently make photos when a molecule is fluorescent. By superimposing a very large number of these photos a superresolution image of the molecule is produced. Betzig managed to use this technique for the first time in 2006.
As the superresolution microscopy techniques of the Nobel Prize winners have made it possible to unravel very small structures, even in living tissue, we are now at the eve of many breakthroughs in microbiology.