Baby stomps…
Molecular robots make their first nanoshares
DailyTechInfo based on the materials of R&D Magazine: Baby steps towards molecular robots
A "walking" molecule created by chemists from Oxford University, so small that it is impossible to see it even in the most powerful microscope, has taken its first steps, the length of which is only about one nanometer.
This case is the first in the history of modern science when a series of tiny steps made by a nanorobot molecule was recorded in real time. All this is a significant milestone in the development of real nanorobots capable of delivering medicines, fighting malignant tumor cells and performing a lot of other work at a microscopic level that is unattainable not only to the naked eye, but also to the weakly naked eye.
"Just imagine how in the future, such tiny molecular machines will be able to carry a payload of molecular sizes, which will be consumables or parts of other, more complex machines that can work even inside living cells," says Dr. Gokce Su Pulcu from the Faculty of Chemistry at Oxford University, "But our ultimate goal is to develop a universal nanotransport network that can be deployed anywhere and through which nanohodoks will carry their loads."
However, before molecular nanorobots can "run" through transport networks, they must first be taught to walk like a child, with small steps. "And this is a very difficult task," Dr. Su said, "For some time, nanomachines and walking nanorobots have already been created, made of DNA molecules, and moving along paths of the same DNA molecules. Unfortunately, such DNA systems are much larger than our molecular "walkers", and they work only in an aquatic environment."
One of the main problems faced by scientists developing all kinds of moving nanorobots is that even the most powerful microscopes are not able to examine objects 10-20 nanometers in size. This, in turn, means that the movement of "nanohods", whose step is about 1 nanometer, can be detected only after this tiny device takes 15-20 steps. And therefore, with the help of a microscope, it is impossible to determine exactly how the device moved from one point to another, whether it walked the distance as it should, or whether it "jumped", "flew" and missed several intermediate steps.
Dr. Su and her colleagues from the Bayley Group research group used a new approach to determine in real time every step that a moving molecular nanorobot takes. This nanorobot consisted of a molecule containing arsenic atoms, and its movement was recorded by the trace it left on the so-called nanopores, holes of very small diameter filled with a certain chemical substance.
The nanopores mentioned above are the product of an innovative DNA sequencing technology developed by Bayley Group scientists and specialists of their subsidiary Oxford Nanopore Technologies. A weak electric current is passed through nanopores filled with a certain type of protein. The "nanohodok" walking along these nanopores causes changes in the structure of the protein, which are the trace left by it and which affect the strength of the current electric current.
"We can't see how our "walker" is moving. But by creating a diagram of changes in the ion current flowing through the pore, we can track how the molecule moves from one fulcrum to another," explains Dr. Su.
In order to prevent their "walker" from breaking away from the surface and floating away into space, the researchers provided him with chemically active "legs" whose atoms form chemical bonds with the material of the surface on which this molecule walks. "It's like if you were walking on a surface covered with an adhesive compound," explains Dr. Su, "Every time the "leg" of the molecule, coming into contact with the surface, sticks to it, forming a chemical bond. And we chose a substance for the legs of the molecule that will allow it to move on many different surfaces."
The implementation of step-by-step movement for such a tiny nanomachine is in itself quite a great achievement. However, a lot of time will pass before the appearance of the first universal programmable nanorobots. "At present, we cannot yet precisely control the direction in which our nanohodok will move. Now it moves in a rather disorderly way," says Dr. Su, "However, if we manage to create something like a road for such molecules, along which it will be much easier for them to move, then the walkers will move along this path, and this means that we will be able to direct them to where we need them.".
The next step of scientists will be to create a walking molecule that can do useful work, for example, carrying some cargo. Currently, scientists are considering the option of placing the load on the "head" of the molecule, where there is enough free space for this. All this is just the first timid steps in the development of a completely new technology, a technology that will be able to bring a lot of useful things to humanity as a whole in the future.
Article by Pulcu et al. Continuous observation of the stochastic motion of an individual small-molecule walker is published in the journal Nature nanotechnology – VM.
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