For his groundbreaking contributions to microscopy. Betzig pioneered a method known as single-molecule microscopy, or “nanoscopy,” which allows cellular structures at the nanoscale to be observed using an optical microscope, for which he shared the Nobel Prize in Chemistry in 2014.
In the fall of 1994, Eric Betzig contemplated what he thought might be the end of his scientific career. He had an intriguing idea of how to capture images at incredibly small scales that were beyond the limits of what was then possible—but, having left a successful research position at Bell Labs to focus on raising his newborn child, he lacked the resources to pursue it.
“I decided to publish the idea, just put it out into the scientific world,” Betzig said. “And I thought that would pretty much be the end of it. I thought I was done with science.”
Hardly. Twenty years later, Betzig’s paper, along with a number of significant achievements afterward, was cited in his being awarded the 2014 Nobel Prize in Chemistry.
Betzig grew up near Detroit. His father worked in the automotive industry, which Betzig credits for contributing to his fascination with engineering and which led him to the Institute. “Caltech offered an intense exposure to theoretical science,” Betzig says. “I don’t think I have ever been pushed as hard in my life as when I was an undergrad.” Beginning as a freshman, he participated in the Summer Undergraduate Research Program (SURF), only in its second year, working with then–aeronautics professor Garry Brown studying instability in jets. “It was through SURF that I suddenly felt like I was scratching the itch to really explore experimental science,” Betzig says.
Betzig continued on to Cornell, where he was first exposed to the field that would define his career: microscopy—the science of using microscopes to view things at scales the naked eye cannot.
There are a number of flavors of microscopy, such as X-ray, electron, and scanning, which offer various types of windows upon the small-scale universe. The classic method is optical, which involves the passing of visible light through lenses, just as we see with our eyes. Optical microscopy is relatively benign, allowing researchers to investigate living organisms. But there’s a catch. At very small scales, optical microscopy runs into a wall, a restriction known in physics as the Abbe diffraction limit, which essentially says that nothing smaller than one-half the wavelength of light, or about 0.2 micrometers, can be discerned by such scopes.
Betzig joined a group at Cornell that wanted to push the boundaries of the Abbe limit. “The idea that you might capture a snapshot of a living cell sounded amazing. I had to be a part of it,” he says. Betzig worked on a number of experiments with some notable early successes, then went on to AT&T Bell Laboratories, where in 1993, he was able to image individual molecules at room temperature past the diffraction limit.
Then, shortly after, he decided to walk away. “I was frustrated,” Betzig says. “The methods of our experiments were now encountering real physical limitations, AT&T was beginning to restrict its investments in Bell Labs, and it seemed to me that the field had become overcrowded. I hit my own limit.” Betzig took time off to focus on his family, published his paper from home, then dipped his toe into private industry. He went to work for his father’s automotive-supply company in the late ’90s, where he developed a number of experimental manufacturing tools. “I was a good engineer but a bad businessman,” Betzig jokes. “I created some great tools, but the automotive industry wasn’t the right fit.”
Still, the call of science beckoned and in 2003, nearly 10 years after he left Bell, Betzig set up a lab in his home, dusted off his old research, and began to tinker with several new ideas. He reconnected with a former colleague and mentor from Bell Labs, Harald Hess. “Harald and I would take trips, to places like Joshua Tree or Yosemite, trying to figure out what we wanted to do with our lives.” On a trip to visit colleagues in Florida, the two stumbled upon an idea—one that resonated with Betzig’s earlier paper in 1994.
Back then, Betzig had been able to take images of individual molecules, but the technique was limited. “If you have a bunch of molecules together, their diffraction-limited spots overlap,” Betzig says. “My idea in 1994 was that if you could find some way in which they differ from one another—and it can be anything, really—then you could isolate them. And hence, you could plot their coordinates.” But how to tag the molecules? Betzig didn’t have an answer at the time.
“People are always exhorted to take risks, and that’s fine... but it’s not a risk unless you fail most of the time.”
Cut to a decade later: While on their visit to Florida, Betzig and Hess learned of advanced techniques used to make individual proteins fluorescent. In essence, researchers could now target and turn individual molecules on and off—almost like a light switch.
Betzig now had his tag. By switching molecules on and off a very small subset at a time, he could capture images of isolated molecules—each glowing independently—though at low resolution. “Each molecule would appear as a fuzzy blob,” he says, but it was enough information for him to find the center and thus determine with high precision the position of each molecule. Betzig realized that by combining thousands of images of these small subsets, he could knit together a super-image in which nanoscale structures sharpened and were clearly visible—beating the Abbe limit.
“It seemed so obvious and so simple,” Betzig said. “We were terrified. We thought, ‘Why hasn’t anyone thought of this yet?’”
Betzig and Hess quickly set up a lab in Hess’s house, and within six months, they were able to build a working prototype of their microscope on the floor of his living room. Their new technique, which they dubbed photoactivated localization microscopy (PALM), was first described in a 2006 paper published in the journal Science, less than a year after they had committed to the idea.
Their discovery ignited interest in a new branch of microscopy. In 2014, Betzig was named a recipient of the Nobel Prize in Chemistry, sharing the prize with William E. Moerner, who developed breakthroughs in single-molecule microscopy, and Stefan Hell, who developed the techniques to trigger fluorescent molecules to glow.
Today, Betzig continues to push the boundaries of microscopic imaging at the Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Virginia, where he has been since 2005.
The proverbial ink had hardly dried on his Nobel announcement when, a few weeks later, Betzig published another paper in Science announcing the creation of yet another instrument—the lattice light-sheet microscope—which produces three-dimensional photo-and-video imaging at microscopic scales with startling resolution.
“As proud as I am of PALM, I think this new instrument is my best work,” Betzig says. “We finally have a tool to understand the cell in all of its complexity.”
Betzig looks forward to other researchers using the tools he’s created, like the lattice light-sheet microscope, to take risks, persevere, and make their own discoveries.
“People are always exhorted to take risks, and that’s fine,” Betzig said in closing his Nobel lecture. “But it’s not a risk unless you fail most of the time. To all of the unknown people out there who have gambled their fortunes, their careers, and their reputations but in the end, failed… Remember that the struggle is its own reward, [along with] the satisfaction that you knew you gave everything you had to make the world a better place.”
photo credit: Scott Council