A group of Chinese researchers has developed a prototype of a microscopic fish robot printed on a 3D printer that can treat cancer cells directly in the human body. An achievement that could revolutionize this type of treatment, as it will destroy tumors much more purposefully, increasing effectiveness while reducing side effects.
Chemotherapy, widely used today in the treatment of cancer, is a very heavy burden for the human body, because its side effects are very significant. In addition, many procedures are currently invasive, requiring operations to reach the treated areas. Scientists from the University of Science and Technology of China and the Institute of Nanotechnology Karlsruhe (Germany) took this problem as a starting point for an innovative solution.
They have created various forms of “robots” of microscopic scale, capable of influencing the human body from the inside. One of the most successful experiments to date is the creation of a “miniature fish” that has been shown to be able to deliver doses of doxorubicin (Latin Doxorubicinum), a drug commonly used in chemotherapy, directly into cancer cells.
This achievement can revolutionize this type of treatment, as it will allow the destruction of tumors more purposefully, reducing side effects for the human body. In the experiment, this microscopic fish was remotely controlled through an artificial vascular network. He moved through fictitious blood vessels and “opened his mouth” only in the presence of cancer cells, delivering a transported dose of medicine.
Robots are printed in “4D”
To create this miniature messenger, the researchers printed it on a 3D printer from a component capable of changing properties under certain conditions. That’s why they talk about “4D”, since the robot has the ability to “transform”.
Scientists explain the choice of their material among others capable of reacting in a similar way by its high biocompatibility, as well as low cost, high load capacity and high adaptability. A key element of their research is hydrogel, a material that reacts to pH, that is, the level of acidity in the environment. If the pH is 9 or higher, it expands. If the pH decreases (i.e. the level of acidity increases), then it naturally decreases.
The researchers used this characteristic to naturally “program” their robot. To do this, they simply printed out a part of the fish at the level of the mouth with a lower density. Therefore, when the fish is exposed to low pH, shrinkage occurs unevenly, and a two-micron hole is formed in the hydrogel. Thus, the medicine can spread.
If you look at the pH of the human body, the process makes sense: the researchers explain that it is much lower in the area of a cancerous tumor. In other words, the “fish” will open its mouth to deliver the medicine only when it is near the appropriate cells, which ensures very precise targeting.
To do this, the fish must be able to move. To do this, scientists first immersed it in a solution of iron oxide. As a result of the transformation, the micro robot becomes sensitive to magnetism. Therefore, it can be carried out through the vessels simply by magnetization. Along the way, the team realized that soaking in solution reduces the reaction rate depending on pH: in this case, it’s just a godsend. So far, the hydrogel has reacted at a pH below 9. The natural pH level of the human body is 7.4. Due to the use of an iron oxide solution, the reactivity was reduced to this level. Since the acidity level around the cancer cells was about 7, the robot was programmed to accurately affect them.
Fish robots, crab robots, butterfly robots…
The team believes that their solution is a breakthrough, since it can be remotely controlled and concrete measures can be taken. Indeed, many projects have been conceived in the field of micro robots, but so far, according to scientists, they have not been able to combine these two characteristics simultaneously. They also worked on other models, although at the moment their experiment with a robot fish is the most used. Crabs, butterflies… The researchers were creative enough to explore the possibilities of changing the shape due to the expansion and compression of the hydrogel.
Thus, they also constructed a crab whose claws, using the same process described above, are able to capture a microscopic element and move it. Its practical application in the human body creates several more problems, since its work is also based on pH changes: the pH fluctuations that it needs do not necessarily correspond to areas in which it would be useful to work. The team also points out improvements that need to be made to their micro-robots. At the moment, they have passed laboratory tests. But in order to be introduced into the human body, their size will have to be reduced even more. It is also necessary to develop a reliable way to track their movements.
