Tiny Robots Made of Living Cells May Clean Up Plastic Pollution in Water

Named for their size, micro and nano plastics are minuscule particles resulting from the breakdown of plastic waste introduced into water systems. These particles have been identified as detrimental to aquatic ecosystems, causing disruptions such as impeding the growth of organisms, diminishing their food consumption, and harming fish habitats.

Developing efficient technologies for the removal of these minuscule particles is crucial to safeguard endangered species and their ecosystems. The design of such technologies must prioritize environmental sustainability, utilizing materials that prevent additional pollution and environmental harm.

Scientists at Brno University of Technology and Mendel University in the Czech Republic have created biohybrid microrobots designed to address the issue of micro- and nano-plastic pollution in water. The innovative robots, featured in a paper published in Advanced Functional Materials, combine biological components, particularly algae, with eco-friendly materials that can be manipulated by external magnetic fields. This approach aims to efficiently remove plastic particles without introducing additional pollution into the environment.

Xia Peng, a co-author of the paper, explained the research focus on utilizing multi-layered TiO₂ microrobots for capturing nano plastics. The initial approach involved incorporating noble metals like Pt for propulsion, which raised costs and potential hazards. To overcome this, the team explored substituting expensive metals with a more economical and readily mass-produced alternative.

Recently, the researchers have been working to identify cost-effective and environmentally friendly materials for their robots, addressing challenges from previous efforts. Peng, in particular, has been exploring the potential use of algae cells, which could be introduced into marine environments without causing harm.

Xia Peng explained that the newly developed robots, Magnetic Algae Robots (MARs), are a fusion of algae and environmentally friendly magnetic nanoparticles. Controlled by an external magnetic field, these robots have a negative surface charge due to -COOH groups on the algae cell surface. In contrast, the micro/nano plastics they target carry a positive surface charge. The positive-negative interaction facilitates electrostatic attraction, facilitating the precise capture and removal of micro/nano plastics by the MARs.

The distinctive composition of the robots crafted by the researchers renders them both environmentally non-polluting and receptive to externally applied magnetic fields. This capability positions them to effectively and sustainably retrieve nano- and micro-sized plastic particles from aquatic environments.

Peng and her colleagues conducted a series of tests to assess their microrobots, and the results were impressive. The microrobots exhibited precise remote control capabilities, effectively removing the majority of tiny plastic particles in the water tanks where they were deployed.

Peng highlighted the impressive performance of their microrobots, noting a high success rate of 92% for nano plastics and 70% for microplastics. She envisions these microrobots as a promising tool for actively addressing plastic pollution in water bodies, contributing to environmental remediation efforts, and mitigating the impact of plastic waste on aquatic ecosystems in the future.

Looking ahead, the team’s magnetic algae robots (MARs) could undergo testing and deployment in oceans and various water bodies. This innovative technology, crafted from cost-effective materials and employing scalable fabrication processes, holds promise for efficiently removing toxic plastic residues. If successfully implemented, these robots could represent a cost-effective solution to address the pervasive pollution of aquatic environments.

In discussing the potential of their magnetic algae robots (MARs), Xia Peng emphasized that these robots have the capability to minimize the necessity for resource-intensive and costly methods currently utilized for plastic waste removal. Future research efforts are expected to delve into the biocompatibility of MARs with aquatic ecosystems, assessing potential impacts on non-target organisms to better understand the environmental implications of their deployment. Additionally, there is an interest in exploring how MARs can complement or be integrated with other technologies, such as sensors for real-time monitoring of plastic concentrations.

Resources

1. ^{ONLINE NEWS} Fadelli, I. & Phys.org. (2023, November 24). Biohybrid microrobots could remove micro- and nano-plastics from aquatic environments. Phys.org. [Phys.org]
2. ^JOURNAL Xia, P., Urso, M., Koláčková, M., Húska, D., & Pumera, M. (2023). Biohybrid Magnetically Driven Microrobots for Sustainable Removal of Micro/Nanoplastics from the Aquatic Environment. Advanced Functional Materials. [Advanced Functional Materials]