Scientists announce fish robot that can eat microplastics in seawater

Microplastics are the remains of plastic waste after rotting in seawater, and are the leading environmental problem of this century. Mixed in water, microplastics naturally find their way into the food chain. Medicine has discovered traces of microplastics in the human body, although its impact on human health is uncertain.

The tiny size of microplastics makes the process even more difficult. That's why the new initiative is so significant.

The fish robot can move flexibly in the water and absorb floating microplastics.

"It is wonderful to successfully develop a robot that can accurately collect and sample microplastics in the marine environment," said Wang Yuyan, an expert at the Polymer Research Institute of Sichuan University. , and also one of the lead authors of the new study, said in an interview.

In a new report published in Nano Letters, Ms. Yuyan and her colleagues describe the advanced device in detail. "As far as we know, this is the first soft robotic device of its kind."

The fish robot is only 13mm in length, can move flexibly in the water and absorb microplastics floating freely in the water. Thanks to the laser system located on the tail, the fish robot can swim at a speed of about 30mm/s, similar to the speed of plankton. More specifically, the fish robot can heal itself in case the outer shell is damaged.

The researchers built the robot based on a material 'popular' in the marine environment: nacre, the lustrous white material that makes up the inner layer of the shells of some mollusks. By stacking layers of molecules on top of each other, the team of scientists was able to create a material with properties close to nacre. This is yet another example of man's attempt to imitate nature.

Fish robot with the ability to clean up marine microplastics.

Thanks to that, the fish robot can expand, can be twisted without affecting performance, it can also pull objects weighing up to 5kg. Most importantly, the fish robot can absorb floating microplastics because organic dyes, antibiotics and heavy metals in microplastics have chemical bonds and electrostatic properties that match the materials that make up the fish robot. .

Tiny plastic waste will stick to the body of the small device, and the marine environment will reduce some microplastics. "After the robot collects microplastics in the water, the researchers can further analyze the composition and toxicity of the waste," Yuyan said.

Having experience in developing self-healing materials, Ms. Yuyan also noticed the new material's ability to self-heal. The shell of the fish robot can heal itself up to 89%, the robot's ability to absorb microplastics is not affected much when the shell is damaged.

However, Ms. Yuyan reaffirmed that this is just a prototype that shows the future potential of fish robots. Currently, the new device can only work on water, its later versions are expected to be more complex and have more diving capabilities. Anyway, today's experimental fish robot can still be a premise for many similar projects in the future.

"I think nanotechnology holds a lot of potential in waste absorption, collection and detection, which can improve performance and reduce operating costs," said Ms. Wang Yuyan.