Breakthrough Nanofiber Sensor Enables Rapid, Ultra-Low Detection of Toxic PFAS Compound GenX in Water

Environmental monitoring is an important industry, as scientists, fueled by sustainability initiatives as well as a general concern for the planet, look for new ways to preserve the environment for future generations. Much of this industry is concentrated on developing new technologies that can better monitor water, air, and soil conditions. Recently, a team of researchers from North Carolina A&T State University and the University of North Carolina Greensboro explored this topic by developing a novel nanoscale sensor capable of detecting ultra-low concentrations of the toxic chemical GenX in water (1). Their study, published in the journal Nanomaterials, introduces a surface-enhanced Raman spectroscopy (SERS) platform that can identify GenX at concentrations as low as 1 part per billion (ppb) in just minutes.

What is GenX?

GenX is the trade name of a chemical compound called hexafluoropropylene oxide dimer acid (HFPO-DA) (2). It is often used in the manufacturing process for fluoropolymers (2). However, manufacturing processes are not foolproof, and, as a result, GenX has found its way into the environment. This is a concern because recent toxicology studies have shown that, despite its shorter molecular chain, GenX poses serious threats to both human health and the environment (3). As GenX continues to appear in rivers and drinking water systems, especially near manufacturing sites, the need for rapid and accurate detection methods has become more important.

What did the researchers do in their study?

In their study, the research team developed a hierarchical nanofibrous SERS substrate using electrospun nylon-6 nanofibers coated with approximately 60-nanometer silver nanoparticles (AgNPs). These silver nanoparticles were deposited using a “hot start” method that optimized their size, shape, and spatial distribution, creating highly active SERS hotspots that amplify Raman signals from GenX molecules (1). This design enabled the team to identify distinct Raman fingerprint peaks for GenX at approximately 751 cm⁻¹ and 813 cm⁻¹, corresponding to the molecule’s –CF₃, –CF₂–, and C–O–C structural groups (1).

What did the new SERS substrate demonstrate?

The new SERS substrate demonstrated a limit of detection (LOD) of 1 ppb and a SERS enhancement factor (EF) as high as 1.3 × 10⁷, which was a significant improvement over previous PFAS detection methods (1). The enhanced GenX Raman signals followed a strong polynomial relationship with GenX concentration, showing near-perfect correlation coefficients (R² = 0.99988 and 0.99704) for the characteristic Raman peaks.

According to the authors, this is the first successful detection of GenX at ultra-trace concentrations using an electrospun nanofibrous SERS platform. Unlike conventional chromatographic or mass spectrometric approaches, which are expensive, time-intensive, and laboratory-bound, this new approach is cost-effective, portable, and adaptable for field deployment (1).

“The findings in this research highlight the potential of the engineered hierarchical nanofibrous SERS substrate for enhanced detection of short-chain PFASs in water, contributing to the improvement of environmental monitoring and management strategies for PFASs,” the authors wrote in their study (1).

What are the implications of this study?

The implications of this study are that the nanofibrous system presented here can be used to detect a wide range of short-chain PFAS compounds. The researchers suggest that future iterations of the platform could be coupled with handheld Raman spectrometers to create on-site PFAS monitoring kits for environmental agencies and water utilities (1).

By combining advanced materials engineering with molecular spectroscopy, this study marks a pivotal step toward democratizing access to high-performance contaminant detection tools. The work not only fills a critical gap in PFAS monitoring but also underscores how nanotechnology and vibrational spectroscopy can jointly address global water safety challenges (1).

References

1. Ismail, A. K.; Mantripragada, S.; Zhao, R.; et al. Rapid and Ultrasensitive Short-Chain PFAS (GenX) Detection in Water via Surface-Enhanced Raman Spectroscopy with a Hierarchical Nanofibrous Substrate. Nanomaterials 2025, 15 (9), 655. DOI: 10.3390/nano15090655
2. Chemours, What is HFPO-Dimer Acid? Chemours. Available at: https://www.chemours.com/en/about-chemours/genx (accessed 2025-11-7).
3. Cordner, A.; Allgeyer, A.; Tallon, L. A. Regrettable for Whom? GenX Chemicals as a Case Study in Detrimental Chemical Substitution. Environ. Sci. Pol. 2025, 174, 104262. DOI: 10.1016/j.envsci.2025.104262