Nanorobots are a classic of science fiction, where they pave the way for true miracles of engineering and medicine and are sometimes the basis of a new generation of augmented super-humans. But in the real world, they remain for the moment confined to the test tubes of laboratories working on this subject. Most experts believe that we will have to wait for major advances in miniaturization technologies and materials science before being able to exploit such machines on a large scale.
But that doesn’t stop researchers from moving in this direction. Proof of this is the latest work from a Hungarian research institute; in a paper spotted by Advanced Science News, a team announced that they had created a new family of tiny robots capable of directly manipulating cells.
An energy problem
These devices measure 30 to 40 micrometers longwhich is about five times larger than a human red blood cell. So it is not a nanobots strictly speaking, since they would have to be made several orders of magnitude smaller to fit this definition. But this size already confronts engineers with many obstacles that force them to think outside the box. Energy, in particular, is a real challenge at this scale. How do you power such a small machine?
The obvious path is to use batteries. Very small models already exist. For example, in 2022, researchers at the German University of Chemnitz presented an accumulator one micrometer long — the equivalent of a single isolated grain of dust. But it is still very difficult to integrate this kind of experimental device into a functional robot. And in any case, batteries generally do not mix well with living organisms.
Laser tweezers to move robots
Instead, the Hungarian researchers took a different approach: they completely forgot about electronic components and opted for a fully mechanical system that could be manipulated from the outside. To do this, they used a technology that has been tried and tested for decades, and even earned its creator a Nobel Prize: optical tweezers.
This concept is based on laser beams, which are by definition composed of photons. These particles each carry a certain amount of energy that is partly transferred to an object when they pass through it. This transfer generates an equal force, but in the opposite direction, in accordance with Newton’s third law. By using a non-homogeneous laser, where the intensity of the beam is maximum at the center and then increasingly weaker at the periphery, we can create a force gradient that can trap and manipulate a small object.
This device works extremely well with inert objects. So bioengineers suggested that these laser tweezers could be used to move individual cells with remarkable precision. Unfortunately, they quickly discovered that this technique was far from ideal in this scenario. Even with a very low-intensity laser, this energy input tends to damage the internal machinery of the cells.
Other researchers have explored alternative approaches, such as attaching microscopic beads to cells so that the laser can use them as “handles.” But this idea was quickly abandoned. It doesn’t prevent the laser from causing damage, and it’s nearly impossible to remove the beads after manipulation, rendering the cells useless.
« It’s a bit like using adhesive to stick cotton to a spatula. You can grab it to move the cotton without crushing it, but it tears when you try to remove it. “, says Lóránd Kelemen, a biophysicist at the HUN-REN research center and lead author of the study.
So his team went for a more sophisticated version of the same concept. Instead of attaching handles to the cell, they designed these famous micro-robots that can be manipulated using optical tweezers. Once moved to the right place, they can grab their target with tiny pincers. The main challenge was to make them delicate enough to close without damaging their contents. To achieve this, the researchers designed an elastic frame with carefully calibrated thickness that can be folded or unfolded with a simple laser shot.
Before nanorobots, real potential in medical research
In the end, we end up with a very versatile microscopic robot. For example, it is capable of transferring a cell from one place to another or of orienting it very precisely. This allows, among other things, to photograph it from all angles to study its internal structure or physiology in real time. This concept could therefore lead to great progress in cellular biology.
In the longer term, it could also serve as the basis for much more complex systems to influence the dynamics of the organism at this small scale. The age of nanobots is fast approaching!
The text of the study is available here.
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