Science News- STED microscopy

This years Nobel prize in Chemistry is a neat one, for the development of stimulated emission depletion (STED) microscopy. This is basically a modification of the existing confocal fluorescence microscope. Instead of scanning a specimen with a single laser to stimulate a fluorochrome the field is scanned with two lasers simultaneously. The first is the typical laser using the appropriate wavelength to excite a particular flourochrome. The second laser is the key new component, this is focused so that it produces a donut of light overlapping the focal point of the first laser. The wavelength of this laser is chosen so that it will prevent fluorescence emission at the normal emission frequency in the donut around the focal point. This works by the "stimulated emission" of the fluorochrome in the donut region, which inhibits emission at the normal wavelength, resulting instead in emission at a different wavelength which can be ignored by the microscope detection system. The end result is that the area from which the fluorescence signal is released becomes much smaller since the only region stimulated in the normal fashion is the small hole inside the donut. This region can be made significantly smaller than the region stimulated either in a regular confocal or in a 2-photon microscope. The end result is superior resolution, down to about 50 nanometers, about 4 times as good as either confocal or 2-photon microscopy. The technique can be used with two fluorochromes, so double labeling is possible, and the fluorochromes can in principle be any of the fluorescent probes in use today, either genetically encoded such as GFP or chemically coupled such as appropriately labeled primary and secondary antibodies (fortunately for EnCor, but see below). Unfortunately the only currently commercially available STED microscope systems are from Leica, not usually known for the marketing of inexpensive products. Even more unfortunately, Leica have an exclusive license on the patented STED technology, so no other company will be able to sell a STED microscope system for several years. This leaves the already embattled researcher with three options; 1. Beg, borrow, steal or in the absolute worst case buy a Leica STED system. 2. Build your own system, but not many people would know how to do that. 3. Don't do anything but watch people who did 1 or 2 have all the fun. Here is a Leica STED tutorial so all you taking option 3 know what you are missing.