Scientists have been creating and testing various nanomachines in laboratories for a long time. In fact, these are molecular constructs whose task is to perform some useful function: for example, deliver drugs to a diseased organ, identify a pathogen, or repair something. When the first "useful" nanorobots appear, will they help colonize Mars and other planets?
These questions are answered by Ben Feringa, professor at the University of Groningen in the Netherlands. In 2016, he, together with Frenchman Jean-Pierre Sauvage and Scotsman Fraser, won the Nobel Prize for the design and creation of molecular machines. “Your nanomachines are made of very common elements like carbon, nitrogen, or sulfur. Can we expect more exotic components in them - for example, rare earth metals or radioactive substances?- This question is very difficult to answer for one simple reason: we still do not know what such molecular constructs can and cannot do. At the same time, despite the large differences in the structure of our nanomotors, rotors and other elements, all of us - my group, Stoddart, Sauvage, and many other colleagues - are still working exclusively with organic molecules. Of course, nothing prevents us from imagining that something like this can be created using exclusively inorganic compounds. For example, to construct a complex connection and make it, like our molecular motors, rotate around its own axis. No one, however, has yet assembled such nanomotors.
The reason is simple. Thanks to the development of pharmaceuticals and polymer chemistry, we have learned to very quickly and well synthesize complex compounds consisting of hydrocarbon chains. I'm sure the same can be done with inorganic compounds, but to do this, we first have to understand how to assemble such molecules.
When it comes to radioactive isotopes, I don't think they will ever become part of nanomachines. Their unusual properties and instability are likely to make them unsuitable for working as part of stable molecular systems that use light or electricity as their energy source.
In this respect, we are more interested in biological molecular motors, hundreds of varieties of which are present in the human body. They are all protein machines, many of which contain metal atoms.
Most often, they play a key role in the reactions that make these biomachines move. Therefore, it seems to me that a combination of metal complexes and organic compounds surrounding them looks the most promising.
This year we are celebrating the 150th anniversary of the periodic table. Could you explain how this achievement of a century and a half helps you make discoveries today?
- The periodic table and the laws inherent in it actually always help us to assess how different types of atoms neighboring in it behave and to predict the properties of some compounds.
For example, some types of our motors have built-in oxygen atoms. Thanks to the table, we understand that sulfur will be similar to it in its properties, but at the same time it is slightly larger in size. This allows us to flexibly control the behavior of such molecular machines, exchanging oxygen for sulfur and vice versa.
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This, of course, does not end with our prediction capabilities. There are many other laws recently discovered that allow predicting some of the characteristics of nanomachines.
On the other hand, I doubt that we can create something like a periodic table for such nanostructures. Here we, if it is possible in principle, do not have enough knowledge.
So, we can roughly predict how molecular motors of different sizes, similar in structure, will behave, but we cannot do this for radically different systems or design something from scratch without conducting experiments.
You recently said that the first full-fledged nanorobots will appear in about fifty years. On the other hand, only a year and a half ago, the first "race" of such nanomachines took place in France. How far are we from the emergence of autonomous nanodevices?
- It should be understood that all molecular machines existing today are very primitive both in structure and in purpose. In fact, both our car, which we assembled in 2011, and these "racing cars" were created not to solve any practical problems, but to satisfy curiosity.
Both we and our colleagues are developing such devices to solve very simple problems - we are trying to figure out how to make molecules move in one direction or another, stop and execute other simple commands. This is an interesting but still purely academic problem.
The next step is much more difficult and serious. It is important to understand whether it is possible to engage them in truly practical tasks: transporting goods, assembling in more complex structures and responding to external stimuli.
For example, nanomachines can be used to create smart windows that respond to street lighting levels and can repair themselves; antibiotics that work only when a certain chemical or light signal appears. Such things, it seems to me, will appear much earlier than you think - in the next ten years.
* Nanobolid * on the race track from a copper substrate.
The creation of full-fledged nanorobots capable of performing operations inside the body or solving complex problems, of course, will take more time. But I, again, am sure that we can do it too. There are countless such robots in the human body, and nothing prevents us from constructing their artificial copies.
On the other hand, we, as I have said more than once, are now at about the same level of development as humanity in the days of the Wright brothers. First, we need to decide what and why we will create, and then think about how to do it.
It seems to me that you should not mindlessly copy what nature has invented. Sometimes completely artificial systems, like airplanes or computer chips, are much easier to create than analogs of a wing or a human brain.
In other cases, it is easier to take what living organisms have already created, for example, some antibodies, and attach a medicine or part of a nanomachine to them. Similar approaches are already being used in medicine. Therefore, it cannot be said unequivocally that any of them will be more promising and correct for all possible applications of nanorobots.
In recent years, two "classes" of nanomachines have appeared - relatively simple structures that receive energy from the outside, and more complex structures, full-fledged analogs of motors, capable of producing it independently. Which ones are closer to reality?
- Chemical motors, somewhat similar to analogs in living cells, really began to appear. We have recently created several similar devices in our laboratory.
For example, we managed to assemble a nanomachine capable of using glucose and hydrogen peroxide as fuel and transporting nanotubes, nanoparticles, and other heavy structures in any direction.
It is difficult to say how promising they are - it all depends on the tasks to be solved. If we need to organize the "transportation" of some molecules, then they are ideal for this. To create smart windows or other gadgets, in turn, you already need to look for other material.
In addition, we still do not understand what exactly we are missing, what analogs of classical machines can be created using molecules, and where our entire sphere will move in general. In fact, we have just started to develop it. So far, only one thing is clear - nanomachines differ from biomachines in our cells, and from their “big sisters” in the macrocosm.
If we talk about the distant future, is it possible to use molecular machines capable of copying themselves to solve global problems, for example, to conquer Mars or other planets?
- It is difficult for me to talk about other worlds, since this issue goes far beyond my competence. Nevertheless, I think that nanomachines are unlikely to be used for such purposes in the first place. When we are trying to master some new and very harsh environment, we need very reliable technology, not something experimental.
Therefore, it seems to me that such machines will first find application on Earth. We can say that this is already happening: in recent years, chemists have created hundreds of very complex structures of many molecules, the so-called supramolecular structures, which can selectively bind to certain ions and ignore everything else.
For example, my colleague Francis Stoddart recently founded a startup in which he develops complexes that can extract gold from mining waste and waste dumps. In the past, the creation of such compounds would have been considered the fantasy of alchemists.
Talk about nanomachines most often causes genuine fear among the public, fearing that future microscopic robots will destroy civilization and all life on Earth. Is it possible to somehow fight this?
“These problems have a lot to do with Creation Machines: The Coming Era of Nanotechnology, written by Eric Drexler in 1986. The scenario of the death of humanity as a result of the self-propagation of "gray mucus" presented in it is known today to almost everyone.
In fact, there is nothing unusual here - when creating new nanomachines, we take the same precautions as when working with new and potentially toxic chemicals.
In this respect, the components of nanorobots are no different in their destructive potential from the “building blocks” from which the molecules of new drugs, polymers, catalysts and other “ordinary” chemical products are assembled.
Like any other drug or food product, these molecular structures will have to go through a huge number of safety tests that will show whether they can "rebel" and destroy humanity.
In fact, there is nothing surprising in such fears - people are used to being afraid of something new and unusual. Every decade there is a new "horror story" from the world of physics, chemistry or biology, which replaces the things to which we are already accustomed. Now, for example, it has become fashionable to fear and criticize the CRISPR / Cas9 genomic editor and artificial intelligence.
What should scientists do? It seems to me that our task is simple: we must help the public to figure out what is true and what is fiction. It is important to understand the practical benefits of these new discoveries and where their real danger lies.
For example, if people understand that CRISPR / Cas9 can cure them of diseases associated with genetic defects, or increase plant productivity, they will have less reason to fear this technology. The same goes for the nanomachines of the future.