Ultrasensitive and quantitative SERS detection using SiO2@Au core-satellite structures on paper-based super-hydrophobic substrates for food safety applications

Achieving highly sensitive surface-enhanced Raman scattering (SERS) detection requires precise collection of trace target analyte molecules into small hot spot regions. In this study, we propose a convenient and cost-effective method to construct a high-performance SERS platform based on the super-hydrophobic delivery (SHD) effect to overcome the diffusion limit during sample evaporation. A paper based super-hydrophobic substrate (PBSH substrate) was employed as a concentrator to enrich the analytes, along with SiO 2 @Au core-satellite structures (SiO 2 @Au CSSs) to form “molecule in hot spot” matrices. Benefiting from the SHD effect and the high SERS activity of SiO 2 @Au CSSs in three-dimensional space, we achieved excellent SERS sensitivity and reproducibility. This platform exhibits a good linear response for detecting Rhodamine 6G (R6G) across concentration ranges from nanomolar (10 −7  M) to femtomolar (10 −13  M) levels, with a low relative standard deviation (RSD) of 6.42 % observed across 30 randomly selected spots. Moreover, the platform enables sensitive detection of various contaminants and multicomponent residues of pesticides and organic dyes in real samples, exhibiting great practical potential in the field of food safety.