Three scientists who created tiny molecular machines received a huge honor Wednesday — the 2016 Nobel Prize in chemistry.
Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa figured out how to combine atoms to make nanoscale machines that can act like motors, elevators, muscles and even a rudimentary car with four "wheels." Their creations are so small that they're about 1,000 times more narrow than a human hair.
The scientists' revolutionary research could lead to a host of sophisticated technologies, from molecular computers to targeted medical therapies and novel energy-storage systems, experts said.
"This is the start of a new molecular era," Sara Snogerup Linse, chair of the Nobel Committee for Chemistry, said after a briefing in Stockholm.
In a molecule of water, the oxygen and hydrogen atoms are held together by covalent bonds sealed with shared electrons. To make a molecule of table salt, a sodium atom transfers an electron to a chlorine atom, and the electrostatic attraction holds these now-charged atoms together in an ionic bond. While such molecules might move around, there's not a whole lot of movement within them (unless those bonds are being broken).
But in the middle of the 20th century, scientists sought to create a different kind of bond: a mechanical bond, a connection such as that between a free-spinning wheel and an axle, that would allow for motion within a nanoscale contraption.
To do that, they had to create a molecule with at least two separate, semi-independently mobile parts. One of the first things they tried to do was connect two molecular rings, like links in a chain. It wouldn't be a machine, per se, but it would show that it was possible to create these mechanical bonds.
This, unfortunately, was even more difficult than it might sound. Scientists in the 1950s and 1960s did report that they'd found bits of molecular chain in their test tubes, but it was so little — sometimes just fractions of a percent, Stoddart said — that it was little more than a chemical curiosity.
Sauvage's discovery in 1983 breathed new life into these efforts. He noticed that photochemically active molecular complexes, which use sunlight to power chemical reactions, seemed to be made of two molecules wrapped around a central copper ion. Minus the ion, it looked remarkably like a chain.
Based on that complex, Sauvage built a system where he placed a molecular ring around a copper ion, and then looped a C-shaped molecule through the ring. The ion delicately held both molecules in place, until the scientists could join a second C-shaped molecule to the first one, effectively closing the loop. The ion could be taken away, and voila — Sauvage had created a two-link chain. Plus, he could do it at far higher yields, about a whopping 42%.
Within a decade, Sauvage's team managed to make one ring rotate around another by adding energy — rather like a fan can rotate when plugged into an electrical outlet. Molecular machines were no longer a pipe dream.
Around the same time, Stoddart was developing molecular creations of his own. In 1991, his team threaded a long rod through a ring, creating a nano-sized axle. When heat was added to the system, that ring would shuttle between two points on the rod.
By 1994, he was able to control that back-and-forth motion. That triumph over random motion would pave the way for even more sophisticated and reliable machines.
Stoddart has since managed to construct a minuscule elevator, which can raise itself about 0.7 of a nanometer above a surface; design an artificial muscle by threading two loops of molecules together; and even build a tiny computer chip with 20 kilobytes of memory. Such molecular parts could revolutionize computer technology.
Feringa developed a key system in the late 1990s: He made a molecular motor that could turn continuously in one direction. That had been a challenge, as spinning parts tended to spin randomly in both directions.
In the decades that followed, he improved the machine's spinning speed, bringing it up to 12 million revolutions per second. He built a tiny nanocar, with molecules that spun rather like wheels, allowing the car to scoot around. He also used molecular motors to spin a glass cylinder that was 10,000 times bigger than the motors themselves.
The three scientists' work has inspired a host of others who continue to push the boundaries with molecular machinery, but the research is still in fairly basic stages, Nobel Prize officials pointed out. The advances, they noted, might be likened to those made to the electric motor in 1830s, when engineers built wheels and spinning parts without knowing that they would ultimately lead to a host of everyday devices, such as food processors and washing machines.
For now, it's unclear what the next big breakthrough will be, scientists said.
"If I could tell you that, I would be running along to my lab and doing it now," Stoddart said in an interview. "But in terms of generalities, I will say that it will be mind-blowing, what can be done even in 10 years' time, let alone 50."
Feringa had a more specific list in mind.
"Think about tiny robots that the doctor in the future will inject in your blood veins and that go to search for a cancer cell, or go in to deliver drugs," he said during a briefing in Stockholm. "There are also smart materials, for instance: materials that can adapt, change, depending on an external signal — just like our body functions."
Donna Nelson, president of the American Chemical Society and professor of chemistry at the University of Oklahoma, agreed that the possibilities were wide open.
"This perhaps will be an area in which most of the applications will follow the award, rather than precede it," she said in an interview. But given the attention that comes with a Nobel, she added, "perhaps this is going to come along faster than we anticipated."
Sauvage is at the University of Strasbourg in France; Stoddart, formerly of UCLA, is now at Northwestern University in Evanston, Ill.; and Feringa is at the University of Groningen in the Netherlands. The three will share the $930,000 prize equally.
The chemistry prize was the last of this year's science awards. The medicine prize went to a Japanese biologist who discovered the process by which a cell breaks down and recycles content. The physics prize was shared by three British-born scientists for theoretical discoveries that shed light on strange states of matter.
The Nobel Peace Prize will be announced Friday, and the economics and literature awards will be announced next week.
The Nobel Prizes will be handed out at ceremonies in Stockholm and Oslo on Dec. 10, the anniversary of prize founder Alfred Nobel's death in 1896.
Nobel, the inventor of dynamite, wanted his awards to honor achievements that delivered the "greatest benefit to mankind."
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2:55 p.m.: The story was updated with additional information throughout.
3:40 a.m.: This article was updated with information about the laureates.