Molecular machine manipulates individual atoms with robotic arm
Image credit: Stuart Jantzen
In an unprecedented feat, researchers based at the University of Manchester have created a molecular-scale robot capable of manipulating individual atoms to build molecules.
Molecular robotics is an emerging field that has not yet spawned practical applications, but the field has the potential to transform technology across many sectors - from how we approach manufacturing to drug development. The potential importance of the field was recognised when three European researchers won the Nobel Prize in Chemistry 2016 for the design and synthesis of molecular machines.
A molecular robot is a machine the size of a single molecule that can be “programmed” to perform complex tasks through mechanical manipulation.
Such machines have arisen in nature to carry out a range of biological tasks, for instance, ribosomes, which build proteins in living things.
“Molecular machines lie at the heart of every biological process. Over billions of years of evolution, nature has not repeatedly chosen this solution for achieving complex task performance without good reason,” said Professor David Leigh, the University of Manchester chemist who led the study.
“In stark contrast to biology, none of mankind’s fantastic myriad of present-day technologies exploit molecular machines in any way at all. Every catalyst, every material, every plastic, every pharmaceutical, every chemical reagent - all function exclusively through their static properties.”
It has been long assumed that artificial molecular robots could never be made to handle individual atoms, due to individual atoms being too reactive and mobile to be manipulated by these devices. This is known as the “sticky fingers” or “fat fingers” problem.
Now, however, Professor Leigh’s group at the university’s School of Chemistry has developed the first molecular robot with the unique capability of manipulating individual atoms to create new molecules. The tiny machines are a millionth of a millimetre in size and are made up of 150 carbon, hydrogen, oxygen and nitrogen atoms.
While building and operating the molecular robots is an immensely complex task, the techniques used by the team are based on basic chemical processes.
Responding to simple chemical inputs from the investigators, the robots use a tiny robotic arm to move a molecular substrate between different activation sites to synthesise one of four different products, including compounds famously tricky to create with conventional methods.
While each robot can handle just one substrate molecule, the processes can be carried out by more than a billion billion billion molecular robots at once.
“By having a billion billion robots doing the same thing simultaneously they can build far more than one or two robots alone,” Professor Leigh told E&T. “However, the scale is so small that a billion billion molecular robots only weigh a few milligrams and a few milligrams of molecular robots can only make a few milligrams of product at a time.”
A large team of these molecular robots working simultaneously could produce useful volumes of materials (“molecular manufacturing”), such as plastics.
According to Professor Leigh, in the future, we could see the creation of “molecular factories” or “nanofactories”, miniature factories which use molecular robots to build functional molecules for drugs, plastics and macroscopic robotics components.
This could reduce demand for material, aid drug discovery, reduce power requirements and aid the miniaturisation of other products.
“When we learn how to build artificial molecular machines that can control and exploit molecular level motion, and interface their effects directly with other molecules and the outside world, it will potentially impact on every aspect of functional molecule and materials design,” Professor Leigh told E&T.