The Institute of Macromolecular Research at Sichuan University recently published its latest research findings in the journal Nano Letters. This is a bionic robotic fish that can swim in the ocean and remove microorganisms by attaching itself to plastics, which are soft, pliable, self-healing bodies.
Micro-plastics are the hundreds of millions of tiny plastic particles that break up from the large plastic products we use every day, such as water bottles, car tires, and synthetic T-shirts. Once dispersed into the environment through the breakdown of large plastic products, they are difficult to remove, and they are one of the biggest environmental problems of the 21st century because they can get into drinking water, agricultural products, and food products, threatening the environment, animals, and human health.
This bionic robotic fish, developed by the Sichuan University Polymer Research Institute, can swim and catch floating micro-plastics and repair itself if cut or damaged during exploration. Measuring only 13 mm in length, this robotic fish can swim and strike at speeds of nearly 30 mm per second, like plankton drifting through the water, thanks to an optical laser system equipped on its tail.
The robotic fish was inspired by elements that grow in the sea, a material called nacre, which is found inside the shells of pearl oysters. The team created the pearl-like material by layering microscopic sheets of various molecules based on the specific chemical gradient of pearls.
According to the study, this resulted in a resilient robotic fish that can flexibly twist its body and even pull up to 5 kg. The organic dyes, antibiotics, and heavy metals in the micro-plastic have strong chemical bonds and electrostatic interactions with the bionic robotic fish’s material, allowing the bionic robotic fish to latch onto pieces of micro-plastic that drift freely nearby. The bionic robotic fish can therefore attach to its surface and collect and remove micro-plastics from the water.