Construction of magnetic Au/Fe3O4/POPs substrate with high enrichment capacity for SERS detection of gastric cancer marker 4-hydroxybenzoic acid

The molecular diagnosis of diseases through the highly sensitive and specific detection of very small amounts of biomarkers in biological samples remains a great challenge, and powerful detection strategies are urgently needed for basic research and clinical applications. Herein, a novel synergistic signal amplification strategy based on Au/Fe 3 O 4 /POPs to integrate magnetic porous composite Fe 3 O 4 /POPs with strong adsorption capabilities for target molecules and gold nanoparticles (AuNPs) with plasmonic properties, is proposed for ultra-high sensitivity and specific Surface-enhanced Raman spectroscopy (SERS) detection of the gastric cancer marker 4-hydroxybenzoic acid (4-HBA). The Au/Fe 3 O 4 /POPs-based SERS assay for gastric cancer-related biomarkers achieved significantly enhanced SERS signals arising from multiple signal amplifications, had good linear calibration from 10 −11 to 10 −5 mol/L, and could detect 4-HBA with a limit of detection (LOD) as low as 1.52 × 10 −12 mol/L. The detection of 4-HBA doped serum exhibited good specificity, homogeneity, and reliability. This material is easy to synthesize and simplifies the sample pretreatment process. This innovative SERS substrate is promising for the rapid detection of disease markers, particularly for early diagnosis and monitoring the effectiveness of gastric cancer treatments.