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Physicist Eric Betzig made a dramatic contribution to the imaging field in the 1980s and 1990s with his work on the near-field microscope. This technology, which shattered the theoretical "diffraction limit" imposed on spatial resolution by the wavelength of light, imaged small structures at higher resolutions than scientists thought possible. Techniques to peer inside living cells at similar high resolutions are still too slow, however. So when Betzig comes to the Janelia Farm Research Campus, opening this fall, he plans to develop a new method—"optical lattice microscopy"—to rapidly image the constant activity within living cells.
HHMI: WHICH FIELDS OF BIOLOGY STAND TO BENEFIT MOST FROM IMPROVEMENTS TO MICROSCOPY?
EB: Basically, the interfaces between cell biology and molecular biology. We understand the genetic sequences by which proteins are made, and we understand, in many cases, the structures of the proteins. What we don't understand in sufficient detail is when they're expressed, or not expressed, within the cell; how that relates to environmental factors; what other proteins are present within the cell right then; how the proteins interact with one another; and how those areas of interaction are localized to drive the cell and its function.
Conventional optical microscopy cannot provide high-enough resolution to address these questions. But if the techniques that are at the edge right now pan out, we've only seen the tip of the iceberg. I make an analogy with astronomy: When people at the turn of the last century looked at Mars through telescopes with inadequate resolution to see any detail, the fuzzy lines they saw started them thinking about built canals and Martian civilizations.
Similarly, when you crack open any issue of Cell or Biophysical Journal, you see tons of interpretive studies based on relatively low-resolution cell images. Oftentimes, the interpretations are necessarily speculative. But as we begin to get higher resolutions, better dynamics, and the ability to access deeper tissue, we're going to get vast improvements in understanding. With factor-of-two or -four increases in each of those areas, we'll be creating this multidimensional space of information that can grow by orders of magnitude. All these systems that we've looked at before very blurrily we will now see in greater detail. It's going to be like the difference between using those old telescopes and using the Hubble Space Telescope.
HHMI: WHICH ASPECTS OF OPTICAL MICROSCOPY NEED TO BE IMPROVED?
EB: The first is new contrast mechanisms: To find out more about the cell optically, you need a wider and better set of labels. Single molecules are basically exquisite reporters of their local environment, and you can optimize them so that the fluorescence of a labeling molecule is sensitive to a parameter of interest. Techniques like fluorescence lifetime imaging give you contrast based on how long it takes for a photon to be emitted from the molecule, which can act, say, as a pH sensor or a viscosity sensor. So this is an ongoing area of interest: both on the chemistry side, in how to create new and better labels, and on the technology side, in how to get the information from the photons.
Photo: Paul Fetters
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