Ultrasensitive aptasensor based on SERS-coupled immunochromatography for rapid detection of fenvalerate in food samples.

Development of an ultrasensitive magnetic biosensing platform using SERS and aptamer for the ratio detection of chlorpyrifos in tea.

The rapid and accurate detection of chlorpyrifos (CPF), a widely used pesticide in agricultural products, is crucial for food safety assurance. While traditional methods like HPLC and GC-MS are accurate, they remain costly, slow, and lack portability. Herein, an ultrasensitive magnetic biosensing platform was developed for the ratiometric detection of CPF in tea by integrating surface-enhanced Raman spectroscopy (SERS) with an aptamer-based recognition strategy. The platform employed a competitive displacement mechanism, where specific binding between aptamer and CPF triggered the release of signal probes upon magnetic separation. This process altered the Raman intensity ratio of two reporter molecules (4-MPY and 4-MBN). The ratiometric sensing approach, combined with magnetic separation, improved operational convenience and reduced matrix interference from complex samples. Furthermore, the platform exhibited a wide linear detection range (10-9 M to 10-4 M) with a limit of detection (LOD) of 1.4 × 10-6 mg/kg. It demonstrated high sensitivity, stability, reproducibility and specificity across six tea varieties, offering an effective solution for detecting pesticide residues in complex food matrices.

Au@AgNPs-based SERS for the simultaneous detection of carbendazim and thiabendazole residues in tobacco leaves

Core–shell Au@CeO2 nanozyme-mediated aptasensor for dual-mode SERS/colorimetric detection of kanamycin

A multi-mode vertical flow immunofiltration detection system based on multifunctional PB@Au NPs for highly sensitive and diversified detection of brucellosis antibodies

Colorimetric-Catalytic-SERS Trimodal Immunochromatographic Assay for Multi-Scenario Monitoring of Gastrointestinal Infections.

Direct pathogen detection in stool samples is the gold standard for diagnosing gastrointestinal infections, yet substantial technical challenges remain. Here, we report a versatile immunochromatographic assay (ICA) for simultaneous detection of both bacteria and virus, integrating a trimodal readout strategy combining magnetic enrichment with colorimetric, catalytic, and surface-enhanced Raman scattering (SERS) signals. We developed a self-assembled magnetic SERS nanozyme by electrostatically layer-by-layer depositing multilayer PtIr nanoparticles and Au nanostars onto a magnetic core, affording strong peroxidase-like activity and electromagnetic enhancement. In addition, a multi-feature fusion neural-network model was designed for intelligent SERS signal analysis, enabling accurate quantification of pathogen concentrations. The method exhibits high analytical performance across all three modalities: in colorimetric mode, the visual limits of detection (vLODs) were 5 × 103 CFU/mL for Escherichia coli O157 and 0.05 ng/mL for norovirus; in catalytic mode, a 2 min substrate-catalysis step reduced the colorimetric vLOD by 100-fold; in SERS mode, the detection limits were further lowered to 8 CFU/mL and 0.11 pg/mL via a quantitative algorithm. Application to 116 clinical stool samples showed detection rates consistent with quantitative real-time PCR, while reducing the assay time to 1/8. Therefore, this trimodal ICA holds strong potential for rapid and accurate detection of gastrointestinal infections across diverse scenarios.

Multiplexed Detection of Cancer Protein Biomarkers via Surface-Enhanced Raman Scattering Immunoassays on Natural Diatomite Strips.

In this study, we used flexible and inexpensive diatomite/AgNPs strips and Layer-by-Layer (LbL) assembly to develop sandwich assays for the detection of cancer biomarkers of interest via Surface-enhanced Raman scattering (SERS). The modified SERS active strips were used to capture antigens of interest, incubate Raman probes, and generate SERS maps based on specific Raman peaks of the Raman probes. Simultaneous detection and quantification of multiple biomarkers, including HER2, CA15-3, CA27-29, PSA, and MUC4, were demonstrated by the immobilization of specific antibodies and the use of uniquely labeled Raman probes. Spatially resolved and co-immobilized multiplexing strategies were developed and successfully validated, showing high specificity and sensitivity with negligible background interference from serum components. The flexible and cost-effective nature of the diatomite/AgNPs substrate, combined with its strong SERS enhancement, offers significant advantages over traditional immunoassay techniques.