Fabrication of a flexible nanofiber membrane for SERS detection of pollutants: An efficient and eco-friendly approach

The development of electrospun nanomaterials as highly efficient and portable substrates for surface-enhanced Raman scattering (SERS) is of great significance for rapid detection of pollutant molecules. In this work, we prepared sustainable polylactic acid (PLA) electrospun nanofibers decorated with silver nanoparticles (Ag NPs) as a flexible SERS substrate through a combined process of facile electrospinning and green plasma treatment. Using rhodamine 6G (R6G) as probe molecule, the PLA/Ag NPs composite nanofibers show excellent SERS performance and allow the detection of R6G at a low concentration of 10-10 M. In addition, the SERS substrate could be used for trace detection of pesticide thiram, and exhibits high sensitivity with a detection limit of 10- 8 M. By taking advantage of the flexibility of the nanofibers, the nanofibrous membrane was pasted on the surface of an apple to sample and detect residual thiram, and the pesticide could be distinctly identified even at a low concentration of 10- 7 M. The presence of dense Ag NPs with numerous hot-spots played a crucial role in the substrate's high sensitivity for SERS detection. This environmentally friendly, self-supporting SERS substrate holds great promise for diverse applications, including environmental monitoring and medical diagnostics.