For scientists it was like going from a choppy, two-minute YouTube clip to a feature film on a flat-screen TV.
The latest breakthrough, published July 30 in Nature Methods, hooks that TV up with high-def cable, if you will. (Scientfic American is part of Nature Publishing Group.) Many biological specimens, like the fruit fly embryo, are so opaque that they scatter large numbers of photons, filling pictures with static. But now, using a technique called structured illumination, the EMBL team has managed to subtract out this interference, making light sheet microscopy even more powerful.
Philipp Keller, who is the lead author of the paper and has joined Howard Hughes Medical Institute since completing the study, compares the process to reconstructing a landscape seen through a blizzard. "All these snowflakes are passing through your field of vision, so parts of the landscape are obscured by them. But if you record multiple images of that landscape, then the snowflakes will have moved on and you can see what was behind them. By recording enough images, you can combine them into a complete reconstruction of the landscape."
For biologists who study development light sheet microscopy, especially using structured illumination, is a godsend.
Kees Weijer of the University of Dundee in Scotland, who studies the migration of cells in chick embryos and slime mold, has been waiting for a light sheet microscope since the EMBL group first publicized its advances. After years of working with other techniques he is thrilled to finally have a scope built for him by Stelzer's lab.
"Light sheet microscopy is a big improvement," he says. "The image quality is just so much better."
"It's really, really groundbreaking," says Michael Davidson of the Florida State University, whose program developed the microscopy Web sites Molecular Expressions, Nikon's MicroscopyU and others. But the addition of structured illumination, Davidson thinks, will be the real game-changer. "That thing is going to take off like a rocket over the next three or four years. It's the first step in what's going to be a long road."
While they wait for a commercial version to come on the market—the technology has been licensed to Germany-based Carl Zeiss optics company—biologists must build each light sheet microscope themselves. At a conference in Dublin on September 2 and 3, researchers interested in the technique plan to meet to swap tips, share ideas and discuss the future.
Keller emphasizes that despite the EMBL group's successes, light sheet microscopy can be used for much more than imaging embryos. With longer observation times, faster images and clearer pictures, he says, great advances in many fields of biology are possible. "It's not a technique that's been developed for a specific purpose. It can go far beyond that," he says. "The discussion was about how to improve microscopy, and this was the result."