STED microscopy

Stimulated emission depletion (STED) microscopy is one of the techniques that make up super-resolution microscopy. It creates super-resolution images by the selective deactivation of fluorophores, minimizing the area of illumination at the focal point, and thus enhancing the achievable resolution for a given system.^[1] It was developed by Stefan W. Hell and Jan Wichmann in 1994,^[2] and was first experimentally demonstrated by Hell and Thomas Klar in 1999.^[3] Hell was awarded the Nobel Prize in Chemistry in 2014 for its development. In 1986, V.A. Okhonin^[4] (Institute of Biophysics, USSR Academy of Sciences, Siberian Branch, Krasnoyarsk) had patented the STED idea.^[5] This patent was unknown to Hell and Wichmann in 1994.

STED microscopy is one of several types of super resolution microscopy techniques that have recently been developed to bypass the diffraction limit of light microscopy to increase resolution. STED is a deterministic functional technique that exploits the non-linear response of fluorophores commonly used to label biological samples in order to achieve an improvement in resolution, that is to say STED allows for images to be taken at resolutions below the diffraction limit. This differs from the stochastic functional techniques such as photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM) as these methods use mathematical models to reconstruct a sub diffraction limit from many sets of diffraction limited images.