WASHINGTON, Sept. 3, 2025 — Detecting microplastics in the environment could soon become faster and more affordable thanks to a new biosensor developed by scientists and published today in ACS Sensors. The living sensor, built from a safe laboratory strain of Pseudomonas aeruginosa, attaches to plastic and glows green under fluorescence, making even tiny plastic fragments visible in water samples.

Tackling the Microplastics Problem

Microplastics—tiny fragments of plastic often invisible to the naked eye—are now found in air, soil, and waterways worldwide. While identifying them is key to directing cleanup efforts, current methods rely on expensive, time-consuming tools such as infrared or Raman spectroscopy.

“Our biosensor offers a fast, affordable, and sensitive way to detect microplastics in environmental samples within hours,” said study author Song Lin Chua. “By acting as a rapid screening tool, it could transform large-scale monitoring efforts and help pinpoint pollution hotspots for more detailed analysis.”

Engineering a Living Sensor

The research team modified a harmless strain of P. aeruginosa, a bacterium commonly found in nature that naturally forms biofilms on plastic. Two new genes were added:

• One gene activates when the bacteria contact plastic.
• The other produces a green fluorescent protein (GFP), causing the cells to glow under the right conditions.
  

In laboratory tests, the engineered bacteria fluoresced strongly when exposed to plastics such as polyethylene terephthalate (PET, recycling symbol 1) and polystyrene (PS, symbol 6), but not when exposed to glass or sand. Within just three hours, measurable fluorescence indicated the presence of microplastics. Importantly, the biosensor cells remained active for up to three days when refrigerated, suggesting portability for field use.

Real-World Testing

To evaluate the biosensor’s environmental potential, the team introduced it to seawater collected from a city waterway. The glowing bacteria revealed concentrations of up to 100 parts per million (ppm) of microplastics. Further analysis with Raman microspectroscopy confirmed the presence of primarily biodegradable plastics such as polyacrylamide, polycaprolactone, and methyl cellulose—demonstrating that the biosensor could detect not only traditional plastics but also newer degradable polymers.

Toward Scalable Monitoring

The findings mark a step forward in creating low-cost, scalable monitoring tools for microplastic pollution. Unlike traditional methods, the bacterial biosensor can deliver results in just a few hours, providing rapid feedback for environmental agencies, researchers, and conservation groups.

Funding

The authors acknowledge support from the Environment and Conservation Fund, Health and Medical Research Fund, Research Centre for Deep Space Explorations, and the Pneumoconiosis Compensation Fund Board.

Paper Access

The abstract will be available on Sept. 3 at 8 a.m. Eastern time: http://pubs.acs.org/doi/abs/10.1021/acssensors.5c01120

About the American Chemical Society (ACS)

The American Chemical Society (ACS), founded in 1876 and chartered by the U.S. Congress, is a nonprofit scientific organization committed to advancing chemistry for the benefit of humanity. With over 150,000 members worldwide, ACS publishes highly cited peer-reviewed journals, organizes scientific conferences, and provides educational and career resources. Its CAS division partners with global innovators by curating and analyzing the world’s scientific knowledge to accelerate discovery.

For more information, please visit: https://www.acs.org

Original Publication
Authors: Yujin Choi, Yeping Ma, Wei Wei, Yoyo Wing Suet Yeung, Jasmine Tsz Ching Wu and Song Lin Chua.
Journal: ACS Sensors
DOI: 10.1021/acssensors.5c01120
Article Title: Detection of Microplastics Pollution Using a Green Fluorescent Protein-Based Microbial Biosensor Coupled with Raman Spectroscopy
Article Publication Date: 3-Sep-2025

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