A team of researchers from the University of Hong Kong has developed the first light-guided nanorobot, a microscopic device that has the potential to be injected into the human body and be directed through its bloodstream, helping surgeons to accurately transport medicines to certain tissues or eliminate tumors in a controlled manner in the future.
The research group of eight members of the Department of Chemistry headed by Professor Tang Jinyao has been working on this project for three years, and last October presented his findings in the pages of the journal Nature Nanotechnology.
The size of this particular submarine oscillates between the five and the 10 micrometers, reason why its dimension is comparable to the one of a blood cell. The structure resembles a small tree made of silicon and titanium oxide, two semiconductor materials of low cost, very sensitive to light and biocompatible with humans. During the synthesis, the components take the form of nanowires that later are arranged in a small structure of nano-tree. The model of the prototype is a “simple” device similar to a bathroom brush.
Previously, the only method to remotely control a nanorobot of this type was by incorporating a tiny magnetic field within the device, a very limited system when it was possible to transmit information and to direct it from the outside.
One of the great achievements of the Hong Kong team is the fact that it has created a mechanism that can be controlled by light, a natural element that has more color variations, directions and focal points than a magnetic field. This nanorobot can respond to the brightness of a light like moths that are attracted to the flames. They move as if they could see it and move toward it.
As he says, light facilitates the handling of these tiny devices, as they allow for more complex maneuvers inside the body, while those that are driven by magnetic fields are more limited despite having more power. Light is a more effective option for communicating between the microscopic and macroscopic world. It will depend on the application you want to give them, but in the future it would be ideal to combine them.
Inspiration came to the scientists through the observation of nature. In particular, the movement of some green algae, unicellular organisms that have evolved with the ability to perceive the direction and intensity of light around them and swim towards that source to perform photosynthesis.
Although the current nanorobot can not yet be used to treat a disease, the researchers work on the next generation of nanorobot systems which will be more efficient and biocompatible. Their applications for biomedicine are intuitively broad, although they must first test it on animals – something that is planed to be done.
In medicine, conventional treatments for cancer such as chemotherapy or radiation therapy act as a pump that destroys cancer cells, but also damages healthy tissues in the process. This model would be able to take the medication directly to the diseased cells, repair them and block their growth or even eliminate them without damaging the healthy ones around.
There are other models that are able to navigate the blood passively, hoping to find damaged cells to act on them. These are active swimmers. The researchers plan to use a type of light to guide the device to the damaged area and then use another one of a different color or intensity to transmit instructions such as the release of the medicine that carries, something they will work in the future.
At the present stage, this small robot is guided by ultraviolet light, easily detectable but causing radiation. Therefore, the team is exploring the possibility of the device being driven by infrared rays, which emit lower energy and therefore cause less damage.
In addition, when running as a solar battery, the engine requires an aqueous solution to produce a chemical reaction. Traditionally oxygenated water, harmful to humans, has been used, so researchers look for possible chemical elements that simulate the components of the blood to improve the compatibility of the engine in the human body.
For decades, science fiction has dreamed of tiny robots that can change our lives, as in the famous movie The Fantastic Journey, in which a group of doctors drove a microscopic submarine into a human body to repair a damaged brain. But with the passage of time, the development of technology has led to the discovery of microscopic components that are presented keys to healing in the future, with some scientists assuring that in 10 or 20 years we will see truly effective nanorobots to fight cancer and other diseases.