Fastest-Ever Movies Could Capture Molecular Movement
CREDIT: Stephan Eisebitt
Tiny things move very fast, which makes looking at them extremely difficult. We may be able to take a single picture of a molecule, and by the time we're ready to take the second one, the molecule has moved on. Visualizing movement at this scale is currently a technological impossibility. But not for long.
With emerging technologies, scientists may soon be able to watch, in real time, as drugs dock on receptors in the cell , or as nanostructures in computers switch polarity to store data. Finally seeing these processes could result in better drugs and faster computers.
Stephan Eisebitt, a physicist at the Technische Universität in Berlin, has begun this process, using an X-ray laser to record two frames of what could eventually become the smallest movie ever shot.
With structures this small, there's a big practical problem of how we record more than one image, Eisebitt told InnovationNewsDaily.
The technique starts by shooting a single pulse of an X-ray laser at an object. Before the light hits the object, a mirror shaves off part of the laser beam and reroutes it back to the target on another, longer path.
It's like throwing a huge rock in a stream. Both fragments of the beam ultimately reach the object, but at slightly different times and locations. As the light from the beams hits the object, it scatters and lands on a single detector, creating a holographic image.
In conventional photography, it would be as though two exposures were captured on a single frame. But because the X-ray fragments land on the sample in different places and create a hologram, calculations can be used to pull apart the two images.
What Eisebitt ended up with in his own experiments were two pictures, separated by only five 100-trillionths of a second, which he could then arrange in a sequence like a movie.
What can happen in that short amount of time? Not much. It's a thousand times faster than biological processes and a million times faster than the switches that run computers. That's why this technique is so powerful.
Eisbitt is especially interested in imaging the electronic processes involved in data storage. X-ray holography could one day be used to make real-time movies of the changes in magnetization that underlie computer memory, Eisebitt said.
Applying the technique to biology, although equally exciting, poses an important problem. The intense pulses of X-ray light cause radiation damage to soft tissues. When your sample is a single cell, the result will be even more severe.
You vaporize it, said Eisebitt.
But once again, the speed of the imaging may make it useful. The sample is gone, but you've collected all the data you need, he said.
For now, Eisebitt is happy to have captured two frames, but in the future it could be possible to increase that number, he said. He is looking forward to the construction of a new facility in Germany, called the European XFEL, that would offer the world's brightest short-wave X-rays. With Eisebitt's help, it may soon also produce some of the world's smallest starlets.