Moerner, William Esco (1953-…), an American physicist, shared the 2014 Nobel Prize in chemistry with the American physicist Eric Betzig and the German physicist Stefan W. Hell . The scientists each received the prize for their work overcoming a physical limitation of the optical (visible light) microscope . The limitation, first stated by the German physicist Ernst Abbe , is that an optical microscope can never achieve a resolution smaller than about 200 nanometers. Resolution describes a microscope’s ability to clearly distinguish details. A nanometer is 0.000000001 meter (1/25,400,000 inch). The three prize winners were able to bypass the limit, producing optical images with a resolution many times smaller than 200 nanometers. Their processes enabled the resolution of structures as small as individual molecules . The award recognized two different methods, one developed by Hell and the other developed by Betzig and Moerner.
Certain molecules can absorb light and then fluoresce (glow) as a result. In 1989, Moerner succeeded in measuring the light absorption and fluorescence of a single molecule.
In 1995, Betzig had a paper published in which he outlined a method of bypassing the Abbe limit that built on Moerner’s work. Betzig suggested using fluorescent molecules of different colors to build an image one color at a time. As long as molecules of the same color were at least 200 nanometers apart, the microscope could resolve them clearly. The different colors could then be superimposed (layered on top of one another) to produce a single image with a resolution under 200 nanometers. Using enough colors could enable researchers to bring the resolution down to the scale of individual molecules.
In 1997, Moerner learned about the green fluorescent protein (GFP). This protein can be bound to other specific proteins in a cell. Under proper conditions, the GFP will fluoresce, revealing the location of the bound protein. Moerner discovered a variant of the GFP that could be turned on and off at will. He thus showed that it is possible to control the fluorescence of a single molecule. When applied to Betzig’s idea of superimposed images, the ability to turn on the fluorescence at different times acted as a substitute for using different colors. Betzig demonstrated the procedure in 2006.
William Esco Moerner was born on June 24, 1953, in Pleasanton, California. He attended Washington University in St. Louis, where he graduated with bachelor’s degrees in electrical engineering, mathematics, and physics in 1975. He then attended Cornell University in Ithaca, New York, receiving a master’s degree in physics in 1978 and a doctor’s degree in physics in 1982. Moerner worked for IBM in San Jose, California, from 1981 until 1995. He held the distinguished chair in physical chemistry in the department of chemistry and biochemistry at the University of California, San Diego, from 1995 to 1998. He then moved to Stanford University in 1998, becoming a chemistry professor. Moerner served as department chair for chemistry from 2011 to 2014.
