Tiny Fish Robot ‘Swims’ Around Picking Up Microplastics

Fish Robot

Pointers at Glance

  • Chinese researchers developed a 15mm long robot that can collect microplastics as it swims.
  • The researchers mentioned that the swimming fish robot could constantly adsorb polystyrene microplastics nearby and transport them elsewhere.
  • The material could also heal itself after being cut, still maintaining its capability to adsorb microplastics.

The 15mm long robot developed by Chinese researchers is light activated and gathers microplastics as it swims.

Proposed Solution to Clean Up Microplastics

Microplastics are identified almost everywhere on the Earth and are harmful to animals if ingested. Once they settle into nooks and crannies at the bottom of waterways, removing such tiny particles from the aquatic environment is challenging. One proposed solution is using small, flexible, and self-propelled robots to reach the pollutants and clean them up.

Recently, researchers in ACS Nano Letters have designed a light-activated fish robot that swims around fast and picks up and removes microplastics from the environment.

The traditional stuff used for soft robots are hydrogels and elastomers. They can be easily damaged in submarine environments. Another material called mother-of-pearl, also known as nacre, is strong and flexible and is identified on the inner surface of clam shells.

Nacre layers have a microscopic gradient, going from one side with many calcium carbonate mineral-polymer composites to the other with primarily a silk protein filler. Inspired by this natural substance, Xinxing Zhang and colleagues wanted to try a similar gradient structure to create a durable and bendable material for soft robots.

The researchers linked β-cyclodextrin molecules to sulfonated graphene, creating compound nanosheets. Then solutions of the nanosheets were incorporated with various concentrations into polyurethane latex mixtures.

A layer-by-layer assembly system created an ordered concentration gradient of the nanocomposites through the material from which the team formed a tiny fish robot that was 15 mm (about half an inch) long.

Turning a near-infrared light laser on and off quickly at a fish’s tail caused it to flap, propelling the robot forward. The robot could move 2.67 body lengths per second at speed faster than preliminarily reported for other soft swimming robots, which is about the same speed as active phytoplankton moving in the water.

What Did Researchers Say About Fish Robots?

The researchers revealed that the swimming fish robot could repeatedly adsorb nearby polystyrene microplastics and transport them elsewhere. It could also heal itself after being cut, still maintaining its ability to adsorb microplastics.

The researchers said that the fish robot could be used for monitoring microplastics and other pollutants in harsh aquatic environments because of its durability and speed.

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