Researchers have designed a group of miniature spherical robots to collect bacteria and small plastic pieces. Source: American Chemical Society
When old food packaging, discarded children's toys, and other improperly managed plastic waste break down into microplastics, they become increasingly challenging to remove. In a study published in the latest issue of "ACS Nano" by the American Chemical Society, Czech researchers describe a group of miniature robots capable of capturing plastic fragments and bacteria from water. Subsequently, the robots can be purified and reused.
Microplastics, measuring 5 millimeters or smaller, are easily ingested by animals, causing harm. These animals then transfer the particles into the human food chain. Meanwhile, microplastic fragments also adsorb various bacteria, including pathogens, posing a greater threat to organisms.
To simultaneously remove microorganisms and microplastics from water, researchers at Brno University of Technology in the Czech Republic developed a miniature robot system. The system consists of many cooperating components that mimic biological communities in nature, such as schools of fish.
The research team connected positively charged polymers to magnetic particles that only move when exposed to a magnetic field. Polymer strands extending from the beads attract microplastics and microorganisms. The final diameter of a single robot is 2.8 micrometers. When exposed to a rotating magnetic field, the robots aggregate together. By adjusting the self-organization into flat clusters of robots, the movement and speed of the robot collective can be altered.
Using Pseudomonas aeruginosa, a bacterium that can cause pneumonia and other infections, the team replicated microplastics and bacteria in the environment. Results showed that the miniature robots successfully captured around 80% of the bacteria, and free plastic beads were also captured by the miniature robots. Subsequently, researchers collected the robots, separated the bacteria using ultrasonic waves, disinfected them under ultraviolet light, enabling their reuse.
