Flexible, robust and reusable Ag nanoparticle-coated polyamide SERS substrates for rapid identification of toxic substances on curved surfaces

Surface-enhanced Raman scattering (SERS) is a powerful and innovative molecular spectroscopy technique for detecting a wide range of hazardous substances. However, the fabrication of SERS substrates is often plagued by high costs, complex procedures, significant contamination, and lengthy production times. In this study, flexible, low-cost, and durable polyamide (PA) fabrics were utilized as the substrate for SERS. Silver nanoparticle-coated polyamide (AgNPs@PA) SERS substrates were fabricated using a simple, efficient, and environmentally friendly magnetron sputtering method. This process avoids the use of costly materials, intricate preparation methods, and toxic chemicals, making it suitable for commercial-scale production. The SERS performance of Ag@PA substrates was systematically evaluated across different sputtering times (15 to 120 s). The optimized Ag-90@PA SERS substrate exhibits remarkable sensitivity, detecting methylene blue at concentrations as low as 10⁻⁹ M, along with excellent signal uniformity and outstanding reusability. Additionally, the inherent flexibility and mechanical strength of the polyamide fabric allowed Ag@PA SERS substrates to detect harmful residues on curved food surfaces using a straightforward wiping method. This flexible, affordable, and sensitive SERS substrate holds great promise for the rapid, trace detection of hazardous substances in food safety applications.