Internal Standard-Embedded Shell-Isolated Satellite Nanostructures for Enhanced SERS Sensing

To address the critical challenge of quantitative analysis in SERS, we designed an internal standard-embedded shell-isolated satellite nanostructure (SHINs-Au) for the accurate and rapid detection of trace substances. These architectures feature three-dimensional plasmonic hotspots engineered through gold satellite encapsulation, with co-embedded internal standards for post-acquisition signal normalization. By precisely controlling the size and spatial distribution of the outer gold nanoparticles (AuNPs), the spatial positioning of hotspots and the distribution of local electromagnetic fields can be finely manipulated at the nanoscale, thereby significantly enhancing Raman responses. Furthermore, the tunability of the outer AuNP size provides a novel strategy to optimize the near-field coupling efficiency of specific molecules and regulate their surface chemical reaction pathways. Employing this platform, we achieved a detection limit of 0.05 mg/L for the representative synthetic drug methamphetamine with excellent post-calibration linearity (R² = 0.9934). This technology offers a robust solution for drugged driving screening and drug-related crime prevention while demonstrating significant potential for public safety management.