Kategorie: News
Scientists unveil bionic robo-fish to remove microplastics from oceans
Researchers at Sichuan University have come up with an innovative solution to detect microplastics and plastic-related pollutants in the water: they have developed a tiny self-propelled robo-fish that can swim around, grab onto free-floating microplastics and repair itself if it is injured or damaged on its journey of discovery.
The robo-fish is only 13 mm long and, thanks to a light laser system in its tail, swims and thrashes around at a speed of almost 30 mm per second, similar to the speed at which plankton drifts around in moving water.
Microplastics are billions of tiny plastic particles that detach from larger plastic objects, for example through friction. They come from products we use every day, such as water bottles, car tyres and synthetic T-shirts. They are one of the biggest environmental problems of the 21st century because once they enter the environment through the breakdown of larger plastic items, they are very difficult to remove and end up in drinking water, products and food, harming the environment as well as human and animal health.
"It is immensely important to invent tools that will allow us to counteract the immense environmental impact that, at the end of the day, 'pollutes' the entire food chain. Here, we have developed a robot that can collect and sample harmful microplastic contaminants from the aquatic environment," said Yuyan Wang, a researcher at Sichuan University's Polymer Research Institute and one of the study's lead authors. Her 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 types of robots".
A robo-fish that is stretchable and flexible and can even support impressive weights
The researchers created the robot from materials inspired by natural elements that thrive in the sea: nacre, the inner coating of mussel shells. The material resembles nacre, different microscopic layers of molecules are layered according to the specific chemical gradient of the model from nature. The researchers were able to show that their novel material consisting of several graphene and plastic layers is suitable for collecting microplastics in a controlled manner.
The result was a robo-fish that is stretchable and flexible and can even support a weight of up to 5 kg, according to the study. Most importantly, the bionic fish can pick up microplastics floating nearby because the organic dyes, and other materials in the microplastics have strong chemical bonds and electrostatic interactions with the fish's materials. This causes them to stick to its surface, allowing the fish to collect microplastics and remove them from the water. "After the robot collects the microplastic in the water, researchers can further analyse the composition and physiological toxicity of the microplastic," Wang said.
In addition, the newly created material also appears to have regenerative capabilities, according to Wang, who specialises in developing self-healing materials. For example, the robotic fish can heal itself up to 89% of its capabilities and continue to 'ingest' plastic particles even if it gets damaged or cuts itself - which can happen frequently when it is hunting for pollutants in rough waters.
This is only a proof of concept for now, Wang said, and much more research is needed - especially in terms of how the system could be used in the real world. For example, the robot currently only works on the surface of the water, so Wang's team will soon be working on more functionally complex robofish that can also operate underwater. Still, this bionic design could provide a starting point for further developments, Wang said. "I believe nanotechnology holds great promise for trace adsorption, contaminant capture and detection, improving intervention efficiency and reducing costs."
Another conceivable application would be robotic fish equipped with sensors that can measure water quality and local microplastic pollution. Further tests will show whether collecting larger quantities of microplastics with the help of robotic fish will work. What is important, however, is the basic approach of using nanotechnology to create materials that are able to 'attract' microplastics. It would also be conceivable to use special water filters to remove even the smallest microplastic particles from the water cycle.
Indeed, nanotechnology will be one of the key players in the fight against microplastics, we think, which is why we find this approach so exciting. Nanotechnology has great potential here, and as materials research gets better, so will the multi-pronged approach to replacing plastic in our everyday lives and, more importantly, filtering microplastic residues out of the environment.