Researchers Develop Living Sensors for Detecting Microplastics

Currently, scientists use microscopes or analytical tools (such as infrared or Raman spectroscopy) to detect microplastics in water samples. Although these techniques are accurate, multiple steps are required to prepare the samples before analysis, and they can be both expensive and time-consuming. To achieve a simpler method, Song Lin Chua and his colleagues used copper...Pseudomonas aeruginosaA bacterium was engineered to create a living microplastic sensor. This bacterium is commonly found in the environment and can naturally form biofilms on plastic materials, although some strains are opportunistic human pathogens. The team aims to make slight modifications to the bacterium to create a living sensor that can easily detect microplastics in water samples.

Researchers added two genes to copper.Pseudomonas aeruginosaNon-infectious laboratory strains of bacteria are used to manufacture sensors. One gene produces a protein that is activated when bacterial cells come into contact with plastic, and another gene produces a green fluorescent protein as a response. In laboratory tests, the engineered bacteria emitted fluorescence in small bottles containing plastic sheets and growth medium, but did not fluoresce in separate bottles with other materials such as glass and sand. Various plastics produced measurable fluorescence within 3 hours, including polyethylene terephthalate and polystyrene. Additionally, the modified bacterial cells remained active for up to 3 days in a refrigerator (39°F, 4°C), and the researchers stated that this indicates it can be transported to the field.

To test the living microplastic sensor as an environmental monitoring tool, researchers engineered copperPseudomonas aeruginosaAdd seawater to the city waterway. Before adding bacteria, the seawater is first filtered and then treated to remove organic matter. Based on the fluorescence intensity values, the microplastic content in the water samples is as high as 100 parts per million. Further analysis using Raman microspectroscopy indicates that the microplastics are primarily biodegradable types, such as polyacrylamide, polycaprolactone, and methyl cellulose. Although preliminary tests were conducted on conventional polymers, the biosensor still detected these microplastics.

“Our biosensor offers a rapid, cost-effective, and sensitive method for detecting microplastics in environmental samples within a matter of hours.," Chua said."By serving as a rapid screening tool, it can transform large-scale monitoring efforts and help identify pollution hotspots for more detailed analysis.。”