OIST researchers develop portable PFAS water sensor

Detecting Forever Chemicals Outside the Laboratory

Environmental actors and local regulators can now detect per- and polyfluoroalkyl substances directly on site without transporting samples to specialized facilities. Researchers at the Okinawa Institute of Science and Technology created a portable, low-cost platform designed to identify these persistent synthetic chemicals using molecularly imprinted polymers and electrical currents.

The Tech TL;DR:

• Researchers developed a portable sensor platform using molecularly imprinted polymers to detect PFOA and PFOS directly in water samples.
• The device uses screen-printed electrodes on repurposed fabric connected to a commercially available potentiostat and a smartphone or laptop.
• Testing on artificially doped fresh and drinking water showed that detected concentrations closely matched actual contaminant levels.

Molecularly Imprinted Polymers Bypass Traditional PFAS Analysis

Per- and polyfluoroalkyl substances, widely known as forever chemicals, resist heat, water, oil, and environmental degradation, making them notoriously difficult to break down. Conventional analysis relies on collecting samples and shipping them to laboratories equipped with mass spectrometry instruments. While accurate, those methods remain costly and time-consuming.

To bypass traditional laboratory bottlenecks, the Okinawa Institute of Science and Technology team designed a new class of molecularly imprinted polymers tailored specifically to fit PFAS molecules. As described in Biosensors and Bioelectronics, these materials form around a target molecule to create a precise binding site. Once the target is washed away, the remaining polymer acts like a lock shaped for a key, earning these polymers the label of synthetic antibodies.

The device detects contamination by measuring changes in electrical current as target molecules bind to the MIP-coated sensor. Higher electrical current shifts indicate greater PFAS concentrations in the sample. Because the process requires no additional chemical reagents, it provides a streamlined alternative for field monitoring.

Screen-Printed Fabric Electrodes Connect to Smartphones

Manufacturing the detection platform relies on a modular and accessible approach. For their prototype, researchers screen-printed 100 disposable electrodes onto repurposed fabric within a few hours. These electrodes feature three dark prongs on a white strip and are coated with MIPs targeted to either PFOS or PFOA. The strip inserts into a small potentiostat—a black dongle measuring electrical current—which plugs directly into a smartphone or laptop for immediate readout.

The underlying manufacturing method allows the target molecule to be swapped out for other members of the broader chemical family. The family encompasses more than 10,000 similar chemicals, with 50 to 150 members currently regulated across the globe. By focusing their initial prototype on PFOS and PFOA, the team targeted the two most common compounds with documented health risks.

Testing in fresh and drinking water artificially doped with PFOA and PFOS demonstrated that the detected concentrations closely matched actual levels in the tested water. For regulatory context, both PFOA and PFOS are regulated at 50 pg mL-1 in Japan.

Low-Cost Devices Empower Local Environmental Monitoring

Accessibility remains a core design goal for the platform. Perrine Lasserre noted that the system empowers local agencies or families to make informed decisions regarding potential contamination, such as alerting municipal authorities or deciding whether to invest in a water filter. Professor Amy Shen emphasized that while further development and field validation are necessary, the combination of synthetic molecular recognition and low-cost electrochemical devices holds significant potential for broadening environmental monitoring.

Additional field testing across diverse hydrological conditions remains required before widespread deployment.