Hess and Betzig had both thought a lot already about how to build a better microscope. In 1993, Betzig published a paper in Science showing that the position of fluorescent molecules under a near-field optical microscope can be identified with precision far greater than the wavelength of light was once thought to allow. And in 1994, in work that was also published in Science, Hess and Betzig showed together that the closely packed points light in a semiconductor could be individually isolated and studied. Combining these earlier studies, Betzig later proposed that molecular-level resolution might be achieved in cells by imaging just a few molecules at a time and identifying each one's center but no one yet knew how to separate out a cell's densely packed proteins to make that possible under physiological conditions.
It was a tool developed in a biology lab that ultimately inspired the two physicists plan to build a better microscope. "In the world of biology there is a new generation of fluorescent proteins that you can switch on at will with a little bit of violet light," Hess explained. He and Betzig learned of these molecules, which biologists can genetically link to cellular proteins that they wish to study, during conversations with Florida State University (FSU) scientist Michael Davidson in April 2005.
The two knew immediately that what they had heard about photoactivatable molecules fit perfectly with their previous work. In that earlier work, Hess said, "we developed something called spectroscopic near-field microscopy, where we spread out a spectrum of light across wavelengths into lots of little glowing things. And that technique allowed us to see the individual constituents of a generalized glow." In fact, that "generalized glow" was much like what scientists see when they use a light microscope to look at fluor
Contact: Jennifer Michalowski
Howard Hughes Medical Institute