Molecular biology techniques allow researchers to attach a label to each copy of a protein they wish to study. Ordinary optical microscopes can detect these molecules, although Hess describes their appearance under the microscope as "little fuzzy round balls." As Betzig's work in the early nineties had shown, pinpointing the center of these fuzzy balls can identify the location of the labeled protein to the nanometer scale. But if the molecules are too close together and usually they are the fuzzy edges appear to overlap and the microscope cannot discriminate between them. So a cluster of labeled molecules appears as a merged glow that cannot be decomposed into individual sources.
But when Hess and Betzig learned of the new fluorescent labels, developed by George Patterson in the lab of Jennifer Lippincott-Schwartz at the National Institute of Child Health and Human Development (NICHD), they realized that they could be the key. Their technology would enable the scientists to separate the glow of labeled proteins inside a cell into individual components, similar to what they had done in their previous work. Visualizing individual molecules would be as simple as limiting the amount of violet light they used to turn on the fluorescent probes, so that they turned on just a tiny percentage of the labeled molecules.
The concept struck them as so obvious, in fact, that they suspected other researchers might already be working to make it a reality. "At the time we thought, 'This is so simple and the time is so ripe,'" recalled Betzig. "There are so many labs that could do this in a week, and we're starting with nothing." But the two immediately got to work with what they did have which turned out to be old optics equipment Hess had saved from their days at Bell Labs, supplemented by the money in their wallets. They dusted off the equipment and set up shop in the living room of Hess's condominium in La Jolla, C
Contact: Jennifer Michalowski
Howard Hughes Medical Institute