Scientists unveil bionic robo fish to remove microplastics from the sea | Plastic

Scientists have designed a small robotic fish that is programmed to remove microplastics from the ocean and oceans by swimming around and adsorbing them on its soft, flexible, self-healing body.

Microplastics are the billions of tiny plastic particles that are fragmented from the larger plastic objects used 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 are spread into the environment through the decomposition of larger plastics, they are very difficult to get rid of, and go into drinking water, produce and food, and harm the environment and animals. and human health.

“It is of great importance to develop a robot to accurately collect and sample harmful microplastic contaminants from the aquatic environment,” said Yuyan Wang, a researcher at the Polymer Research Institute at Sichuan University and one of the lead authors on the study. The team’s new invention is described in a research article in the journal Nano Letters. “As far as we know, this is the first example of such soft robots.”

Researchers at Sichuan University have unveiled an innovative solution to detect these contaminants when it comes to water pollution: to design a small self-propelled robo fish that can swim around, attach to free-flowing microplastic and fix itself if cut or damaged while you were on the expedition.

The robo fish is only 13 mm long, and thanks to a light laser system in the tail, swims and flaps around at almost 30 mm per second, corresponding to the speed at which plankton drift around in moving water.

The scientists created the robot from materials inspired by elements that thrive in the ocean: Mother of Pearl, also known as Nacre, which is the inner cover of seashells. The team created a material similar to Nacre by laying different microscopic sheets of molecules in layers according to Nacre’s specific chemical gradient.

This made them a robo fish that is elastic, flexible to twist, and even able to pull up to 5 kg in weight, according to the study. The most important thing is that the bionic fish can adsorb nearby free-flowing pieces of microplastic because the organic dyes, antibiotics and heavy metals in the microplastic have strong chemical bonds and electrostatic interactions with the fish’s materials. This causes them to cling to the surface, allowing the fish to collect and remove microplastics from the water. “After the robot has collected the microplastic in the water, the researchers can further analyze the composition and physiological toxicity of the microplastic,” said Wang.

In addition, it appears that the newly created material also has regenerative abilities, said Wang, who specializes in the development of self-healing materials. So the robotic fish can heal itself to 89% of its ability and continue to adsorb even in case it experiences damage or cuts – which can happen often if it goes in search of contaminants in rough water.

This is just a proof of concept, Wang notes, and much more research is needed – especially on how this can be distributed 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 can offer a head start on other similar projects, Wang said. “I believe nanotechnology has great promise for sporadic absorption, collection and detection of pollutants, improving intervention efficiency while reducing operating costs.”

In fact, nanotechnology will be one of the key players in the fight against microplastics, according to Philip Demokritou, director of the Nanoscience and Advanced Materials Research Center at Rutgers University, who was not involved in this study.

Demokritous’ laboratory also focuses on using nanotechnology to get rid of microplastics from the planet – but instead of cleaning up, they are working to replace them. This week, in the journal Nature Food, he announced the invention of a new plant-based spray coating that can serve as an environmentally friendly alternative to plastic food packaging. Their case study showed that this starch-based fiber spray can ward off pathogens and protect against transport damage as well, if not better, than today’s plastic packaging alternatives.

“The motto of the last 40 to 50 years of the chemical industry is: let’s make chemicals, let’s make materials, lay them out there and then clean up the mess 20 or 30 years later,” Demokritou said. “It is not a sustainable model. So can we synthesize safer design materials? Can we extract materials from food waste as part of the circular economy and turn them into useful materials that we can use to solve this problem? ”

This is low-hanging fruit for the field of nanotechnology, said Demokritou, and as research on materials improves, the multifaceted approach of replacing plastic in everyday life and filtering out microplastic residues from the environment.

“But there is a big difference between an invention and an innovation,” Demokritou said. “Invention is something no one has thought of yet. Right? But innovation is something that will change people’s lives, because it makes it commercialized, and it can be scaled. “