Double enhanced flower-like SERS sensor based on aptamer modification for high specific recognition and sensitive rapidly detection of kanamycin

Abstract

Chronic intake of animal-derived foods with excessive kanamycin (Kana) residues risks human drug accumulation, posing significant health threats. To mitigate this, a layer of 4-mercaptophenyl-boronic acid (MPBA) was incorporated between the branched Au nanoflowers (NFs) core and the Ag shell to generate an inter-metallic nanogap, resulting in an aptamer (Apt)-functionalized surface-enhanced Raman scattering (SERS) probe (Au NFs-MPBA@Ag-Apt). When combined with MPBA as the Raman probes, exhibits an intense SERS signal at 1060 cm⁻¹. Concurrently, magnetic nanoparticles modified with flower-like molybdenum disulfide (Fe₃O₄@MoS₂@Ag-Apt) were synthesized. These particles possess a strongly paramagnetic Fe₃O₄ core enveloped by a high-surface-area, flower-like MoS₂ layer, efficiently anchoring Ag nanoparticles (NPs) and Kana-Apt for enhanced target capture. Coupling semiconductor MoS₂ with Ag NPs creates a coupled enhancement: electromagnetic amplification between Ag NPs and at the Ag NPs-MoS₂ interface boosts “hot spots” density. As a semiconductor, MoS₂ facilitates separation of photogenerated electron-hole pairs when interfaced with Ag NPs, driving substantial interfacial electron transfer toward Kana molecules. This substrate achieves a remarkable enhancement factor (EF) of 8.1 × 10⁹. This integrated SERS sensor, using two types of probes at the same time, enables highly specific recognition, rapid, sensitive quantification of Kana. The detection range was 1 × 10¹ ~ 1 × 10⁶ pg/mL, and the limit of detection (LOD) was 0.23 pg/mL. Compared to conventional methods, this biosensor exhibits superior detection breadth and sensitivity. Applied to milk analysis, recoveries were 93.0 ~ 103%. Its portability aligns with point-of-care testing (POCT) needs, offering a viable platform for food safety monitoring.