Once this year's Nobel Prize for Physics had been awarded to the invention of blue LEDs, was there much chance that the prediction of conducting polymers winning the Chemistry? Aside from the committees, who knows? But, rather than something biological as is often the way or something about organic synthetic chemistry, this year's Chemistry has been awarded to Eric Betzig (born 1960) now at the Jannelia Farm Research Campus and Howard Huges Medical Institute, Stefan Hell (born 1962, first Romanian-born Nobel laureate) now at the Max Planck Institute for Biophysical Chemistry and German Cancer Research Center and William "W.E." Moerner (born 1953) now at Stanford University. The prize is awarded "for the development of super-resolved fluorescence microscopy".
Just as there were proclamations that we could never make a blue LED, so too it was assumed that optical microscopy could never achieve resolution greater than half the wavelength of the light being used. This year's laureates turned to fluorescent molecules to help them to circumvent this limitation and take microscopy into the depths of the nanoscopic.
Quite bizarrely, aside from a blatant typographical error on the Nobel page "They Brought Optical Miscroscopy into the Nanodimension" [sic], the organization also asks visitors whether they have heard of nanoscopy...it makes one wonder about who they think will be reading the information about the Nobel Prize for Chemistry. But the wording of the press release "In what has become known as nanoscopy" almost suggests by its tone that the author hadn't heard the word until they got the announcement. Maybe I'm overthinking this...so back to the science.
In 1873, microscopist Ernst Abbe set the physical boundaries for the maximum resolution of a traditional optical microscope, which translates into it never being able to better 0.2 micrometers. But, in the year 2000 Stefan Hell developed stimulated emission depletion (STED) microscopy wherein two beams of laser light are used to image a sample. One laser stimulates fluorescent molecules while the second quenches all fluorescence outside a nanometer-sized volume. He demonstrated that by scanning a sample nanometer by nanometer, he could breach Abbe's limit.
Meanwhile, Betzig and Moerner, working separately, developed single-molecule microscopy. Their method exploited the ability to switch on and off the fluorescence of individual molecules. The same area of sample is then imaged multiple times, with just a clutch of interspersed fluorophores being stimulated to glow with each scan. The resulting images are then superimposed to generate a dense super-image that has nanoscopic resolution. Betzig demonstrated this technique for the first time in 2006.
Until this work, optical microscopy was limited to cells, bacteria, mitochondria and other such entities. Theoretically, there is now no structure in the nanoscopic realm that cannot be imaged using such a technique, which has opened up viruses, the interior of cells and mitochondria, proteins and other macromolecules, and even small molecules to optical imaging.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".