Scientists have designed a small robotic fish that is programmed to remove microplastics from the seas and oceans by swimming and adsorbing them on its soft, flexible, self-healing body.
Microplastics are billions of small particles of plastic that fragment into the larger plastic things that are 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 dispersed in the environment due to the decomposition of larger plastics, they are very difficult to remove, paving the way for drinking water, products and to food, harming the environment and animals. and human health.
“It is very important to develop a robot to accurately collect and sample harmful microplastic contaminants from the aquatic environment,” said Yuyan Wang, a researcher at Sichuan University’s Polymers Research Institute and one of the lead authors. study. His team’s new invention is described in a research paper 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 for tracking these pollutants when it comes to water pollution: designing a small, self-propelled robot fish that can swim, sticking to freely floating microplastics, and fixing if it is cut. or damaged during shipment.
The robbed fish is only 13 mm long and, thanks to a light laser system in its tail, swims and flies at almost 30 mm per second, similar to the speed at which plankton move in moving water.
The researchers created the robot from materials inspired by elements that thrive in the sea: mother-of-pearl, also known as mother-of-pearl, which is the inner shell of clams. The team created a mother-of-pearl-like material in layers of several microscopic sheets of molecules according to the specific chemical gradient of mother-of-pearl.
This turned them into a robo fish that is elastic, flexible to rotate and even capable of throwing up to 5kg in weight, according to the study. Most importantly, bionic fish can adsorb pieces of microplastics that float freely nearby because organic dyes, antibiotics, and heavy metals in microplastics have strong chemical bonds and electrostatic interactions with fish materials. This causes them to stick to their surface, so that fish can pick up and remove microplastics from the water. “After the robot collects the microplastics in water, researchers can further analyze the composition and physiological toxicity of the microplastics,” Wang said.
In addition, the newly created material also appears to have regenerative skills, said Wang, who specializes in the development of self-healing materials. Thus, robotic fish can heal up to 89% of their capacity and continue to adsorb even in the event of damage or cuts, which could often happen if they are going to hunt for contaminants in turbulent waters.
This is just a proof of concept, Wang points out, and much more research is needed, especially on how it could be implemented 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 robotic fish that can go deeper underwater. Still, this bionic design could provide a launch pad for other similar projects, Wang said. “I believe that nanotechnology is very promising for the adsorption, collection and detection of traces of pollutants, improving the efficiency of the intervention while reducing operating costs.”
In fact, nanotechnology will be one of the most important players in the fight against microplastics, according to Philip Demokritou, director of the Center for Nanoscience and Advanced Materials Research at Rutgers University, which did not participate in this study.
Demokritou’s lab is also focused on using nanotechnology to get rid of the planet’s microplastics, but instead of cleaning them up, they are working to replace them. This week, in the journal Nature Food, he announced the invention of a new herbal spray coating that can serve as an environmentally friendly alternative to plastic food wrappers. His case study showed that this starch-based fiber spray can defend against pathogens and protect against transport damage just as well, if not better, than current plastic packaging options.
“The motto of the last 40 or 50 years for the chemical industry is: we make chemicals, we make materials, we put them out there and then we clean up the disaster 20, or 30 years later,” Demokritou said. “This is not a sustainable model. So can we synthesize safer design materials? Can we derive food waste materials as part of the circular economy and turn them into useful materials that we can use to address this problem?
It is a low-level fruit for the field of nanotechnology, said Demokritou, and as research on materials improves, so will the multi-purpose approach of replacing plastic in our daily lives and filtering its waste. environmental microplastics.
“But there is a big distinction between an invention and an innovation,” Demokritou said. “The invention is something that no one has thought of yet. Right? But innovation is something that will change people’s lives, because it reaches the market and can be scaled up. “