Molecular machines, self-eating cells and flatlands physics take Nobel prizes
The Nobel Prizes, which recognize exceptional work across a range of disciplines, are being announced this month, and we now know the winners of the prizes in three fields of science: physics, chemistry and medicine. Here's what you need to know about the advancements in each area that led to the award of some of the world's most prestigious prizes.
Awarded to: David J. Thouless, University of Washington; F. Duncan M. Haldane, Princeton University; J. Michael Kosterlitz, Brown University (United States)
The behavior of matter at the molecular level follows a set of rules proscribed by the discipline of physics – up to a point. When said matter is subjected to extreme conditions like very hot or cold temperatures, intense pressure or a super-thin state, things begin to get a bit bizarre and are better described by the mind-stretching world of quantum physics. It's exactly these strange states of matter in which the three winners of the Nobel Prize in Physics specialized.
In decoding what happens to matter when it's basically tortured, all three researchers turned to topology to help them.
"Topology describes the properties that remain intact when an object is stretched, twisted or deformed, but not if it is torn apart," said the the Royal Swedish Academy of Sciences (RSAS) in Stockholm, which awards the prizes each year. "Topologically, a sphere and a bowl belong to the same category, because a spherical lump of clay can be transformed into a bowl."
In the world of topology, the changes that would make a ball of clay into a bowl happen along a set course, in which things proceed according to clearly defined mathematical steps.
By applying these steps to what happens to matter when it's in a two-dimensional state known as the flatlands, or when it is supercooled (under a discipline known as condensed matter physics), the researchers were able to flip previous quantum physics assumptions on their heads and open the door to experimentation with entirely new strange states of matter.
As one example, Thouless and Kosterlitz changed what was believed to be happening to matter in the flatlands under temperature fluctuations. The previous belief was that in such a state, there was no atomic order. Without order, there could be no orderly transitions in the phases of matter. By applying topological concepts to the problem however, the pair realized that phase transitions were indeed possible – only not in the way water turns to ice, by reorganizing its molecular structure. In the flatlands, they discovered that the secret to phase change was in tiny vortices which, at low temperatures formed tight pairs but at high temperatures spun off in the material away from each other.
"Topological insulators, topological superconductors and topological metals are now being talked about," said the RSAS. "These are examples of areas which, over the last decade, have defined frontline research in condensed matter physics, not least because of the hope that topological materials will be useful for new generations of electronics and superconductors, or in future quantum computers. Current research is now revealing the secrets of matter in the exotic flatlands discovered by this year's Nobel Laureates."
Winner: Yoshinori Ohsumi, Tokyo Institute of Technology (Japan)
Human cells have a very important housekeeping function whereby spent cellular material is broken down into substances that can be used for energy. This process is known as autophagy, which comes from the Greek words "auto," meaning "self," and "phagein" meaning to eat. The waste material is disassembled in a part of our cells known as the lysosome where it's deposited by cellular bodies known as autophagosomes.
In the late 1980s a biochemist named Yoshinori Ohsumi decided to look at the way in which cellular waste was handled in yeast cells to try to shed light on the relatively poorly understood process of autophagy. He created mutated yeast cells that lacked the enzymes necessary to break down cellular waste. He then activated autophagy by starving the cells. By his reasoning, the process should have caused autophagosomes to accumulate in the cells' vacuoles, the equivalent of human lysosomes. Sure enough, that's exactly what happened.
Further research on his part, involving the study of thousands of yeast mutants, eventually led him to unravel the autophagy process in greater detail, including working out which genes were essential for the process. Moving on from there, he identified the proteins encoded by those genes and he figured out how they affected autophagy. "The results showed that autophagy is controlled by a cascade of proteins and protein complexes, each regulating a distinct stage of autophagosome initiation and formation," said the RSAS.
Since then, we've discovered that autophagy is critical in battling bacteria and viruses, that it contributes to the development and differentiation processes in embryos and that it plays a role in aging. When the process goes wrong, it's been linked to Parkinson's disease, type 2 diabetes and cancer.
"Autophagy has been known for over 50 years but its fundamental importance in physiology and medicine was only recognized after Yoshinori Ohsumi's paradigm-shifting research in the 1990's," said the RSAS. "For his discoveries, he is awarded this year's Nobel Prize in physiology or medicine."
Awarded to: Jean-Pierre Sauvage, University of Strasbourg (France); Sir J. Fraser Stoddart, Northwestern University (USA); Bernard L. Feringa, University of Groningen (Netherlands)
In terms of development, the molecular motor is at the same stage as the electric motor was in the 1830s, when scientists displayed various spinning cranks and wheels, unaware that they would lead to electric trains, washing machines, fans and food processors. Molecular machines will most likely be used in the development of things such as new materials, sensors and energy storage systems.
That's what the RSAS had to say about the awarding of the Nobel Prize in Chemistry to three researchers who've pushed the world of micro-machinery steadily forward since the early 1980s.
The journey toward machines that are made from molecules rather than steel began in earnest in 1983 with Jean-Pierre Sauvage. Working in the field of photochemistry, Sauvage discovered that he had come upon two molecules that were linked around a copper ion. Removing the copper ion kept the molecules linked, forming the start of a chain known as a catenane. While molecular chains are nothing new, what was important here is that the molecules were linked mechanically – one ring around another – rather than by sharing electrons in their outer shells, forming the covalent bonds that typically join them together.
In 1991, Fraser Stoddart figured out how to thread a molecular ring onto a molecular axel. He did this by creating a ring with no electrons and a rod that was electron rich. When placed in solution, the electron-poor ring threaded itself onto the electron-rich axle through the power of attraction, forming what is known as a rotaxane.
Ben Feringa came along in 1999 and leaped the field of molecular machinery forward by building the first molecular motor with molecules moving in the same direction, rather than spinning randomly in opposite directions as they tend to do. He did so using pulses of UV light that activated molecular rotor blades that had chemical ratchets built in that kept them spinning in one direction. Feringa's research group has now gotten the motor to turn at 12 million revolutions per second and even built a molecular car that uses the motors as wheels.
Since these discoveries laid the groundwork for molecular machines, other researchers have continued to advance the science of the super small. According to the RSAS, one of the more notable breakthroughs happened when a molecular robot that can grab and assemble amino acids was built using a rotaxane. Stoddart has since built a molecular elevator, molecular muscle and a molecule-based computer chip that could one day revolutionize computing the way the internal combustion engine revolutionized transportation.
While these awards wrap up the Nobel Prizes in scientific fields, there are still more to be awarded across other disciplines. The famed Nobel Peace Prize will be bestowed on October 7, with the Nobel Memorial Prize in Economic Science and the Nobel Prize in Literature announced on October 10 and 13 respectively. Since its launch in 1901, 874 individuals and 26 organizations have been awarded the Nobel Prize.