This micro-printer is built in DNA and self-assembles

This micro-printer is built in DNA and self-assembles

Even if it is still quite rudimentary as it is, this concept could transform many industrial niches in depth.

DNA is a real gem of bioengineering. It is exceptionally stable, making it a medium of choice for genetic information. It also has structural peculiarities that allow it to interact with other elements. And these properties can also be hijacked by particularly cunning bio-engineers; because once isolated from the rest of the cellular machinery, DNA is neither more nor less than a veritable microscopic LEGO brick.

Provided you have a sequence of ideas, it is thus possible to make constructions that are both ridiculously small, but also surprisingly complex; many researchers have already imagined concepts of micromachines built with nothing but DNA. The concept is not new, far from it; but the development of new simulation and modeling techniques is changing the situation considerably.

To be convinced of this, just take a look at the impressive work of the team of biophysicist Erik Benson, affiliated with the prestigious University of Oxford. They are working on a concept as intriguing as it is fascinating: to produce functional DNA-based micromachines capable of self-assembly. And recently, their experiments took a new step: they managed to produce a real functional micro-printer, composed exclusively of about 18,000 base pairs of DNA!

DNA, a LEGO brick for bio-engineers

To achieve this, the researchers began to try to replicate mechanisms that already exist in industry at the macroscopic scale, but at the microscopic scale and only on the basis of DNA. In particular, they succeeded in producing a structure that works like a motor capable of moving on an axis.

The team then used this concept in their printer. They have integrated these small biomotors into a print head which can thus move on a central axis. This is also motorized and mounted on a pair of rails made of DNA; the head can thus move on two axes, as in a traditional printer.

The researchers then use small fragments of DNA and RNA (more precisely, oligonucleotides) specially prepared for the occasion; these signal oligonucleotides are interpreted by the system as instructions which make it possible to define the position of the head.

Once firmly in place, the head can then catalyze a chemical reaction which makes it possible to “selectively modify ‘pixels’ on a canvas” before moving to the next pixel to repeat the operation.

DNA
© Sangharsh Lohakare – Unsplash

A self-assembling structure

Succeeding in producing such an assembly on this scale is already a small technological feat in itself. Because to achieve this, the researchers obviously could not bring their tweezers to assemble the different elements by hand. Indeed, DNA may be a fairly simple molecule chemically speaking, but that does not mean that it is easy to assemble.

The structure of proteins is an infinitely complex problem. It is governed by a multitude of very subtle factors. Certainly, we have advanced knowledge of certain mechanisms; but overall we are still relatively far from understanding their dynamics on a global scale. Researchers are therefore gradually replacing the old methods of empirical analysis, which are time-consuming and taxing, with computational methods based on computer simulations.

It is this approach that has enabled Alpha Fold to completely revolutionize this discipline by offering an immense catalog of protein structure (see our article). And in the case of this printer, the researchers also used simulation to help.

To avoid having to take into account all these complex interactions, they used computers and simulation. Their goal: to produce a self-assembling systemon the sole basis of llaws of physics that govern the structure of molecules and proteins. “It’s like a magnetic puzzle”, explains Erik Benson in an interview with Interesting Engineering. “If the system is well designed, the parts stand between themselves”.

For now, this printer is still quite rudimentary. But it is nonetheless a very impressive proof of concept. Ultimately, Benson and his team hope to achieve a system capable of “printing” very complex molecules directly.

Systems of this kind could transform bioengineering in depth, with applications in many industrial niches including the pharmaceutical branch. © Myriam Zilles – Unsplash

The future of bioengineering?

And that’s a very exciting prospect. Indeed, these complex molecules are at the heart of many advanced industrial processes; they are used in particular for the design of vital pharmaceutical products. The problem is that they are very complicated to obtain. Their production is now based on extremely heavy, complex and expensive industrial processes. And like in any industry, this complicated production makes the end products more expensive and less accessible.

At this level, a tiny bio-printer could completely change the game; no need to be a great specialist to understand that it would be much simpler starting from a simple cocktail of molecules, letting it self-assemble as a printer, then giving it instructions by adding just the right amount of signal oligonucleotides.

In addition to being much simpler to use, this technique has another decisive advantage compared to other heavy industrial processes: extensibility. Instead of investing in a state-of-the-art machine, it would be enough to increase the amount of initial solutions to generate more printers, or any other self-assembled mechanism of this type.

At present, this technique is still far from being mature enough to consider large-scale applications. But once it is, we will probably witness a profound transformation of certain branches of industry, even if it is still too early to draw up an exhaustive list of the concrete implications. And all this thanks to the same molecule that preserves our genetic heritage!

The text of the study is available here.

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