Scientists have designed a tiny robotic fish programmed to remove microplastics from seas and oceans by swimming around and adsorbing them onto its soft, flexible, self-healing body.
Microplastics are the billions of tiny plastic particles that fragment from the larger plastic things we use every day, such as water bottles, car tires and synthetic T-shirts. They are one of the biggest environmental problems of the 21st century because once they have spread into the environment through the breakdown of larger plastics, they are very difficult to remove and end up in drinking water, manufacturing and food, damaging the environment. environment and animals and human health.
“It is of great importance to develop a robot that can accurately collect and sample harmful microplastic pollutants from the aquatic environment,” said Yuyan Wang, a researcher at the Polymer Research Institute at the University of Sichuan and one of the lead authors. of the research. Her team’s new invention is described in a research paper in the journal Nano Letters. “To our knowledge, this is the first example of such soft robots.”
Researchers from the University of Sichuan have unveiled an innovative solution to detect these pollutants when it comes to water pollution: to design a small self-propelled robo-fish that can swim around, cling to free-floating microplastics and repair itself if it is cut or damaged during his expedition.
The robo-fish is just 13mm long, and thanks to a light laser system in its tail, it swims and flutters around at nearly 30mm per second, comparable to the speed at which plankton floats around in moving water.
The researchers made the robot from materials inspired by elements that thrive in the sea: nacre, also known as nacre, the inner lining of shells. The team created a material similar to nacre by layering several microscopic layers of molecules according to nacre’s specific chemical gradient.
This made them a robo-fish that is stretchy, flexible to turn and even able to pull up to 5 kg, according to the study. Most importantly, the bionic fish can adsorb nearby free-floating bits of microplastics, as the organic dyes, antibiotics, and heavy metals in the microplastics have strong chemical bonds and electrostatic interactions with the fish’s materials. As a result, they cling to the surface, allowing the fish to collect and remove microplastics from the water. “After the robot has collected the microplastics in the water, the researchers can further analyze the composition and physiological toxicity of the microplastics,” Wang says.
In addition, the newly created material also appears to have regenerative abilities, said Wang, who specializes in developing self-healing materials. So the robotic fish can heal itself to 89% of its ability and continue to adsorb even if it experiences some damage or cutting – which can often happen when it hunts for contaminants in rough water.
This is just a proof of concept, Wang notes, and much more research is needed, especially on how it could be deployed in the real world. For example, the soft robot currently only works on water surfaces, so Wang’s team will soon be working on more functionally complex robo-fish that can go deeper underwater. Still, this bionic design could provide a launch pad for other similar projects, Wang said. “I think nanotechnology holds great promise for trace adsorption, collection and detection of pollutants, improving intervention efficiency and reducing operating costs.”
Indeed, nanotechnology will be one of the key players in the fight against microplastics, said Philip Demokritou, the director of Rutgers University’s Nanoscience and Advanced Materials Research Center, who was not involved in this research.
Demokritou’s lab is also focusing on using nanotechnology to remove microplastics from the planet, but instead of cleaning them up, they’re working on replacing them. This week, in the journal Nature Food, he announced the invention of a new plant-based spray coating that could serve as an eco-friendly alternative to plastic food packaging. Their case study showed that this starch-based fiber spray can ward off pathogens and protect against shipping damage just as well, if not better, than current plastic packaging options.
“The motto for the chemical industry for the past 40 to 50 years has been, let’s make chemicals, let’s make materials, put them there and then clean up the mess 20 or 30 years later,” Demokritou said. “That is not a sustainable model. So can we synthesize safer design materials? As part of the circular economy, can we extract materials from food waste and convert them into usable materials with which we can tackle this problem?”
This is low-hanging fruit in nanotechnology, Demokritou said, and as materials research gets better, so will the multi-pronged approach to replacing plastic in our daily lives and filtering the microplastic residue from the environment.
“But there is a big difference between an invention and an innovation,” Demokritou said. “Invention is something that nobody has thought about yet. Right? But innovation is something that will change people’s lives because it commercializes and is scalable.”