A team of scientists from Germany and China shared the results of an amazing experiment. Scientists have created a DNA nanobot, consisting of only one molecule, and launched it into a two-dimensional maze, designed on the principle of origami. The so-called DNA navigator managed to find a way out.
Recall that DNA origami technology allows you to create various structures from DNA strands. This is possible due to the fact that long DNA molecules are composed of nucleotides that form pairs: adenine with thymine, cytosine with guanine. By specifying the sequence of nucleotides in the chain, you can achieve that it will fold and fasten in the right places and at the right angle. In this way, you can create an infinite number of structures.
In this case, a team led by Friedrich Simmel of the Technical University of Munich and Chunhai Fan of the Chinese Academy of Sciences used DNA origami technology to create a maze that resembles a mathematical tree graph. In this case, the “passages” of the labyrinth have so-called DNA staples, to which another molecule can attach. At the same time, areas without such “clues” serve as “walls”.
It is specified that the resulting maze is structurally equivalent to a ten-vertex rooted tree (the diagram is shown below). It contains one entrance and one exit.
A maze is structurally equivalent to a ten-vertex rooted tree. Vertex A marks the entrance. Possible routes are marked in red, but only one (on the right) is correct. Illustration by Nature Materials.
The authors of the work explain that the tiny device they created is called a DNA walker. It moves through chain reactions of DNA hybridization (the combination of suitable single-stranded nucleic acids into one molecule).
According to him, such a mechanism provides the ability to turn in the maze passages. As a result, if several DNA nanobots are launched into such a structure, each of them will be able to independently explore one of the possible routes, which will provide a parallel depth-first search (this is one of the methods for traversing the graph).
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To help the DNA nanobot choose the only correct path from many options, the scientists chemically modified the top of the tree graph representing the exit.
To help the DNA nanobot choose the right path from a variety of options, scientists have chemically modified the exit from the maze. Illustration by Nature Materials.
During the experiments, the specialists observed the movements of the DNA navigators using a scanning atomic force microscope and a very high resolution microscope. The first method makes it possible to track paved routes and areas that the DNA walker has not yet visited. The second method provides fluorescent visualization of the route with nanoscale resolution.
The researchers are confident that this kind of development will help expand opportunities in the field of nanotechnology, biomolecular self-assembly and artificial intelligence. Such DNA navigators can be used to store and transmit information, as well as in medicine, for the diagnosis and treatment of various diseases, including oncology.
This work is described in more detail in an article published in the journal Nature Materials.
Yulia Vorobyova