Tumor microenvironment activated SERS-response stable magnetic nano-trackers for symptom monitoring of H2O2

Magnetic nano-detection systems for monitoring symptoms subsequent to cancer treatment have drawn significant attention within the domain of therapeutic diagnostics. However, the weak affinity of target analytes with traditional magnetic SERS substrate and complex matrix interference impede the achievement of high sensitivity and precision necessary for practical H 2 O 2 applications. Herein, Based on Fe 3 O 4 @SiO 2 @Au seed-MBN (4-mercaptobenzoonitrile) @Au (FSAMA) substrate and the electro-driven adsorption strategy, this study develops a SERS sensor for quantification of H 2 O 2 residue. The magnetic core can improve cytocompatibility and reduce cytotoxicity with the inorganic SiO 2 layer. Au@DTNB (5,5'-Dithiobis-(2-nitrobenzoic acid)) @Ag molecules can be adsorbed onto the “hotspot” region of FSAMA substrate to obtain enhanced SERS signals. Though the enhanced second-harmonic generation (SHG) effect, the H 2 O 2 oxidizes the Ag layer of FSAMA-Au@DTNB@Ag to Ag (I), which will significantly cause changes the SERS signal, which is improved by 2-3 orders of magnitude. The incorporation of inner-layer labeling molecules within the Au NPs enhances the stability of SERS signal output while maintaining excellent Raman signal contrast for H₂O₂ detection. In summary, the FSAMA-SERS sensing system developed for detecting H₂O₂ levels may serve as a promising platform for diagnostic and prognostic monitoring, applicable across a wide range of complex serum samples.