Magnetic-responsive Fe3O4@PDA@AgNPs SERS substrates for ultrasensitive detection of multi-component trace industrial dyes

In this work, integrated in-situ reducibility of polydopamine (PDA) with magnetic-responsive performance of ferroferric oxide (Fe 3 O 4 ) nanoparticles, a series of Fe 3 O 4 @PDA@AgNPs were engineered through in-situ grown silver nanoparticles (AgNPs) on the surface of Fe 3 O 4 nanoparticles. The synthesized Fe 3 O 4 @PDA@AgNPs could serve as superb surface enhancement Raman scattering (SERS) substrates for ultrasensitive detection of multi-component industrial dyes in the complex environment. With 4-aminothiophenol (4-ATP) as probe molecules, the Fe 3 O 4 @PDA@AgNPs demonstrated exceptional SERS sensitivity and uniformity, achieving an enhancement factor as high as 7.8 × 10 6 . Notably, the Fe 3 O 4 @PDA@AgNPs demonstrated outstanding magnetic response and molecular enrichment effect, and realized multi-component detection of Rhodamine 6 G (R6G) and Nile Blue A (NBA) molecular mixtures. The detection limit for R6G and NBA was 1 × 10⁻⁷ M and 5 × 10⁻⁷ M respectively. The magnetic Fe 3 O 4 @PDA@AgNPs represent outstanding SERS platforms, and would hold great potential in the quantitative and qualitative detection of dye molecules.