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19. Apr. 2022
Microrobots, intelligent machines that can detect cancer cells, perform surgery or clean the environment of harmful substances, are already known in scientific circles, they are not new. But what the CEITEC scientists have come up with is worth paying attention to. This is evidenced by the interest of the prestigious scientific journal Chemical Society Reviews, which has published the work of the young scientist Martina Ussia and her supervisor Martin Pumera, even presenting it to the professional world from the front page.
Polymers are the future
Where the smart micromachines already presented differ from those being worked on by Martina Ussia and her colleagues is in their composition. Until now, scientists have used mostly inorganic materials such as titanium, platinum or iron to create microrobots. The disadvantage of using these materials is that, among other things, unwanted side effects occur sooner or later. Often, they are not environmentally friendly. CEITEC scientists want to avoid this. Inspired by nature, they see polymers as the future.
The term polymer comes from Greek and denotes many parts. It refers to macromolecules, i.e. chains of same molecules with different shapes and sizes. This results in numerous classes of polymers whose diverse properties Brno scientists are trying to use in the production of micro- and nanorobots. For a better idea, there are natural and synthetic polymers. All living organisms consist of natural ones, such as proteins or nucleic acids, etc.
"Polymers, such as stimulus-responsive hydrogels, soft programmable matter, rubbery elastomers, and liquid crystal polymers (LCPs), play an essential role in achieving adaptive mechanisms of smart micromachines," describes Martina Ussia. She points out that polymers are already used in the production of artificial systems, but mostly in larger robots, with very few examples on a micro- and nano-scale.
Movement due to light, temperature or for example magnetic field
In her article, Martina Ussia lists ways in which polymers can be used to power micro- and nanorobots in a liquid environment, based on a review of recent research by other scientists[UM(1] . [UM(2] They use, for example, light, heat, sound or magnetic fields to move polymer-based micromachines. By combining these different sources of powered particles with micro-machines, they can achieve that controllable motion. They can use this for any purpose, depending on the properties of the polymer classes used.
"Colleagues formulated engineered self-propelled PLGA microrobots that can modulate the doxycycline hyclate (DOX) drug release from days to months, thus providing the treatment and prevention of periodontal diseases," says Martina Ussia, describing one of many examples that confirm the great potential of polymers.
Treatment without side effects
Due to growing environmental concerns, polymers have come to the fore, largely due to their biodegradability and biocompatibility)[UM(1] . They are already used primarily in biomedicine to improve controlled drug delivery. In the future, medicine could go even further, according to Martina Ussia. Thanks to polymer-based micro- and nanorobots. Indeed, they have the potential to fully replace existing treatments, for which we also observe a negative impact. "Instead of chemotherapy, which can have devastating side-effects on humans, we can use these computer-controlled nanorobots that will destroy the cancer cells, and simply disappear when the mission is complete. This is how they can be used instead of antibiotics and basically for anything you can think of. Instead of pills, they can treat with gentle micromachines," says Martina Ussia.
Microrobots in action. Some in a year, others in decades
Currently, Martina Ussia is focusing on three areas of research – the destruction of bacteria in water, the recognition and removal of microplastics in the ocean and the use of polymers for biomedicine. All without the need for inorganic material.
It is furthest along in the first area, where it is trying to respond to the increasing resistance of bacteria to antibiotics. Thanks to cooperation with other institutions in Brno, such as Masaryk University, and with some dentists, Pumera's team is working on how to help patients with titanium dentures, who are more likely to have inflammation, without antibiotics. "It's actually water with microrobots in a glass. The patient rinses their mouth with it and the intelligent machines, unnoticeable to the eye, locate and destroy the bacteria. We would like to put this into practice in about a year," says the enthusiastic scientist.
But the next use of smart machines will not be so fast. The biggest gap in research is the difficulty of applying what Martina and her colleagues can do so far mostly under the microscope. There is a lack of technology and collaboration between scientists across disciplines. "We can teach microrobots to recognise cancer cells and remove them. We can inject them into the body of, say, a mouse, but we can no longer see, how they behave inside. We don't have the machines to do that. We can only imagine and study separately the motion and their biochemical abilities," explains Martina Ussia. But she adds that at the current rate of development, this will be possible in perhaps 10 years.
The research gap could be filled by her success in March, when a paper she published with Martin Pumera, entitled Towards micromachine intelligence: the potential of polymers, was published by one of the most cited scientific journals. "We aim to attract scientists from all other disciplines to collaborate, we believe they will react soon," concludes Martina Ussia with a smile and some hope.
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