Apr 6 2010
To find out what the inside of a living cell looks like, biophysicists of the University of Goettingen and the University of California in Los Angeles have developed an optical method that allows a better and contrast-richer look at individual cells and cell tissue. The results are presented in the "Proceedings of the National Academy of Sciences" journal.
This procedure – called Super resolution Optical Fluctuation Imaging(SOFI) – works as follows: Scientists colour cell structures that are to be seen with fluorescent molecules. The change of the light intensity of the molecules can be recorded with a microscopic camera that can take not only 1 but 100-1000 pictures per second.
The analysis of those illumination images yields information about the spatial distribution of the luminous molecules. SOFI may be combined with each light- or broad-field microscope. The classical optical microscope has already used lights to depict research objects, but the limit of the wave length of light caused the problem that details smaller than 200 nanometres could not be visualised.
However, electron or x-ray microscopes are no alternatives either, as vacuum and low temperatures destroy living cells, whilst newly-developed optical methods, such as Stimulated Emission Depletion(STED) microscopy, allow a 3D resolution on the nanometer scale but are technically extremely complex.
SOFI is now building a bridge between the classical optical microscopy and the complex ultra-high resolution microscopy. Therefore, the fluorescence microscopy can be seen as one of the most important methods in modern molecular cell research.