Magnetic-assisted and aptamer-based SERS biosensor for high enrichment, ultrasensitive detection of multicomponent...

The high-sensitivity detection of low-concentration multicomponent biomarkers in the blood of heart failure (HF) patients using surface-enhanced Raman spectroscopy (SERS) remains a significant challenge. In this study, an ultrasensitive biosensor for the detection of multicomponent HF biomarkers was designed. This biosensor utilizes Au@Ag nanoparticles (Au@Ag NPs) functionalized with Raman reporter molecules (RaRs) as SERS probes, and Ag-coated Fe₃O₄ nanoparticles (Fe₃O₄-Ag NPs) modified with internal standard (IS) molecules as the capture substrate, offering the dual advantages of magnetic enrichment and SERS enhancement. Additionally, specific aptamers or antibodies were conjugated to the surfaces of Au@Ag NPs and Fe₃O₄-Ag NPs to specifically recognize target proteins to construct a three-layer composite structure (Fe₃O₄-Ag/HF biomarkers/Au@Ag). The limit of detection (LOD) of HF markers for cTnI, NT-proBNP, and sST2 is 0.1 pg/mL, 1.0 fg/mL, and 1.0 fg/mL, respectively, surpassing most reported methods. Additionally, the analysis of 45 clinical serum samples revealed no statistically significant differences between the SERS-based results and those obtained by conventional clinical methods, as confirmed by the Shapiro-Wilk test (p > 0.05). In conclusion, this SERS biosensor successfully developed an easy-to-operate accurate diagnosis method capable of simultaneous, quantitative detection of multiple HF biomarkers and provided a new technique for accurate diagnosis of other diseases in clinical testing.