Rapid and scalable fabrication of electrospun cellulose acetate nanofiber-based SERS sensors for ultrasensitive pesticide residue detection on non-planar surfaces.

AuNPs-decorated electrospun cellulose acetate nanofiber (AuNPs@CA-NF) SERS substrates were fabricated using a straightforward magnetron sputtering approach. Magnetron sputtering enables not only the uniform deposition of gold nanoparticles on electrospun nanofiber membranes, but also offers advantages such as high speed, scalability for mass production, and the absence of chemical reagents. Consequently, the optimized AuNPs@CA-NF SERS substrate achieved a detection limit of 10− 11 M for 4-mercaptobenzoic acid (4-MBA), with reliable signal uniformity (RSD = 9.5%) and strong storage stability. The excellent linear relationship between SERS intensity and logarithmic concentrations shows great potential for rapid and quantitative determination of hazardous molecules. Moreover, thanks to the excellent flexibility of the electrospun polymer substrate, the SERS substrate can also detect pesticide residues on irregular fruit surfaces through a simple “adhere-and-read” method. The flexible electrospun polymer SERS substrate achieves a detection limit of 10− 7 M for thiram, underscoring its strong potential for rapid and ultra-trace monitoring of hazardous substances in food safety.