Robots in medicine

Geektimes, blog of ASUS Russia

Today, research groups around the world are trying to find the concept of using robots in medicine. Although it is more correct, perhaps, to say "already groped." Judging by the number of developments and the interest of various scientific groups, it can be argued that the main direction was the creation of medical micro-robots. This can also include robots with the prefix "nano-". Moreover, the first successes in this area were achieved relatively recently, only eight years ago.

In 2006, a group of researchers led by Sylvain Martel conducted a successful experiment for the first time in the world by launching a tiny robot the size of a fountain pen ball into the carotid artery of a live pig. At the same time, the robot moved through all the "waypoints" assigned to it. And over the years since then, micro robotics has made some progress.

One of the main goals for engineers today is to create such medical robots that will be able to move not only through large arteries, but also through relatively narrow blood vessels. This would make it possible to carry out complex types of treatment without such a traumatic surgical intervention.

But this is far from the only potential advantage of micro robots. First of all, they would be useful in the treatment of cancer, purposefully delivering the drug directly to the malignant formation. The value of such an opportunity is difficult to overestimate: with chemotherapy, drugs are fed through a dropper, causing a severe blow to the entire body. In fact, it is a strong poison that damages many internal organs and, for the company, the tumor itself. This is comparable to carpet bombing for the sake of destroying a small single target.

The task of creating such micro robots is at the junction of a number of scientific disciplines. For example, from the point of view of physics – how to make such a small object move independently in a viscous liquid, which is blood for it? From the point of view of engineering – how to provide a robot with energy and how to track the movement of a tiny object through the body? From the point of view of biology – what materials should be used to make robots so that they do not harm the human body? And ideally, robots should be biodegradable, so that you don't have to solve the problem of their withdrawal from the body yet.

One example of how micro-robots can "pollute" a patient's body is a "bioraketa".

This version of the micro robot is a titanium core surrounded by an aluminum shell. The diameter of the robot is 20 microns. Aluminum reacts with water, during which hydrogen bubbles form on the surface of the shell, which push the entire structure. In the water, such a "bioraketa" swims in one second a distance equal to 150 of its diameters. This can be compared to a two-meter tall man who swims 300 meters, 12 pools in a second. Such a chemical engine works for about 5 minutes thanks to the addition of gallium, which reduces the intensity of the formation of an oxide film. That is, the maximum power reserve is about 900 mm in water. The direction of movement is given to the robot by an external magnetic field, and it can be used for point delivery of medicines. But only after the "charge" runs out, there will be a scattering of microbeads with an aluminum shell in the patient, which does not have a beneficial effect on the human body, unlike biologically neutral titanium.

Micro-robots should be so small that it will not be possible to simply scale traditional technologies to the desired size. No standard parts of a suitable size are also produced. And even if they did, they would simply not be suitable for such specific needs. And therefore, researchers, as it has happened many times in the history of inventions, are looking for inspiration from nature. For example, in the same bacteria. At the micro, and even more so at the nanoscale, completely different physical laws apply. In particular, water is a very viscous liquid. Therefore, it is necessary to apply other engineering solutions to ensure the movement of micro robots. Bacteria often solve this problem with the help of cilia.

Earlier this year, a group of researchers from the University of Toronto created a prototype of a 1 mm long micro robot controlled by an external magnetic field and equipped with two grippers. The developers managed to use it to build a bridge. Also, this robot can be used not only for drug delivery, but also for mechanical tissue repair in the circulatory system and organs.

Muscle RobotsAnother interesting trend in micro robotics is robots driven by muscles.

For example, there is such a project: an electrically stimulated muscle cell to which a robot is attached, whose "spine" is made of hydrogel.

This system, in fact, copies the natural solution found in the organisms of many mammals. For example, in the human body, muscle contraction is transmitted to bones through tendons. In this biorobot, when the cell contracts under the action of electricity, the "spine" bends and the transverse crossbars acting as legs are attracted to each other. If one of them moves a shorter distance when bending the "ridge", then the robot moves towards this "leg".

There is another vision of what medical micro-robots should be: soft, repeating the forms of various living beings. For example, here is a robo-bee (RoboBee).

However, it is not intended for medical purposes, but for a number of others: pollination of plants, search and rescue operations, detection of toxic substances. The authors of the project, of course, do not blindly copy the anatomical features of a bee. Instead, they carefully analyze all kinds of "constructions" of organisms of various insects, adapting and embodying them in mechanics.

Or another example of the use of "structures" available in nature is a micro–robot in the form of a bivalve mollusk. It moves with the help of flapping "flaps", thereby creating a jet stream. With a size of about 1 mm, it can float inside a human eyeball. Like most other medical robots, this "mollusk" uses an external magnetic field as an energy source. But there is an important difference – it only receives energy for movement, the field itself does not move it, unlike most other types of microrobots.

Big robotsOf course, the medical equipment fleet is not limited to micro-robots alone.

In science fiction films and books, medical robots are usually presented as a replacement for a human surgeon. They say that this is a kind of large device that quickly and very accurately performs all kinds of surgical manipulations. And it is not surprising that this idea was implemented one of the first. Of course, modern surgical robots are not able to replace a whole person, but they are already fully trusted for sewing. They are also used as extensions of the surgeon's hands, as manipulators.

However, in the medical environment, disputes about the appropriateness of using such machines do not subside. Many experts are of the opinion that such robots do not provide special benefits, but due to their high price they significantly increase the cost of medical services. On the other hand, there is a study according to which patients with prostate cancer who have undergone surgery with a robot assistant require less intensive use of hormonal drugs and radiotherapy in the future. In general, it is not surprising that the efforts of many scientists turned out to be aimed at creating micro-robots.

An interesting project is Robonaut, a telemedicine robot designed to assist astronauts. This is still an experimental project, but this approach can be used not only to help people as important and expensive in training as astronauts. Telemedicine robots can also be used to provide assistance in various hard-to-reach areas. Of course, this will be advisable only if it is cheaper to install a robot in the infirmary of some remote taiga or mountain village than to keep a paramedic on a salary.

And this medical robot is even more highly specialized, it is used to treat baldness. ARTAS is engaged in the automatic "digging out" of hair follicles from the patient's scalp, based on high-resolution photographs. Then a human doctor manually implements the "harvest" into the bald areas.

After all, the world of medical robots is not at all as monotonous as it may seem to an inexperienced person. Moreover, it is actively developing, ideas and experimental results are being accumulated, and the most effective approaches are being sought. And who knows, perhaps during our lifetime the word "surgeon" will mean a doctor not with a scalpel, but with a jar of micro-robots, which will be enough to swallow or inject through a dropper.

Portal "Eternal youth" http://vechnayamolodost.ru10.12.2014