Ag nanoparticle-embedded fish scales as SERS substrates for sensitive detection of forever chemical in real samples

Abstract

Biological materials with unique surface properties provide a new avenue for fabricating green and sensitive SERS-active substrates. Herein, we present a simple but efficient method to prepare surface-enhanced Raman scattering (SERS) substrates by depositing silver nanoparticles (AgNPs) on fish scale substrates using an evaporation-induced self-assembly method (EISA). Characterization of the formed flexible Ag-impregnated substrate proved outstanding SERS sensitivity, uniformity, and reproducibility properties, with a Raman enhancement factor of 1.3 × 106 and a relative standard deviation of 6.4 %. Using this powerful fish scale substrate, a toxic environmental pollutant perfluorooctane sulfonamide (PFOSA) was indirectly detected in lake water, soil, and human urine samples. Due to its chemical structure, it is difficult to detect low concentrations of PFOSA in real samples. Interestingly, malachite green (MG) was smartly used as the Raman label for PFOSA detection in real samples. One of the main appeals is that the concentration of PFOSA can be correlated with a decrease in the SERS signal of MG in real samples. In conclusion, the strategy employed and reproducible SERS substrates may have diverse applications in clinical and environmental analyses.