Triple-enhanced Raman scattering sensor based on superhydrophobic/-philic microsphere platform and heating evaporation assisted for high-sensitivity detection

The ability to detect molecules in small volumes of highly diluted solutions is crucial for applications such as food quality and safety, environmental monitoring, biomedical diagnostics, and so on. The primary concern lies in the sensitivity and efficiency of detection technology. In this work, an ultra-sensitive surface-enhanced Raman scattering (SERS) detection strategy is presented, which is based on superhydrophobic/-philic microsphere SERS (SSM-SERS) platform and heating evaporation assisted for high-sensitivity detection. Relying on the heating-assisted evaporation, the evaporation efficiency of the droplet is increased by 378.5 times, and the deposition area after evaporation is reduced by 10.4 times, leading to the extremely high detection efficiency and further enrichment of the target molecules. When the microspheres array approaches the superhydrophobic/-philic (SH/SHL) substrate, the optical-plasmonic hybrid structure is formed, enhancing light-matter interactions and resulting in an improvement of the Raman signal. The optimized SERS sensor is capable of detecting Rhodamine 6 G (R6G) at the femtomolar level (10−16 M), with a sample volume of only 5 μL and an enhancement factor of 3.29 × 109. Considering the misuse of fish drugs, malachite green (MG) and methylene blue (MB) were chosen to validate the performance of SERS sensor. These findings highlight the consistent high sensitivity of the SERS sensor, offering valuable insights for applications in food safety and related fields. •Novel strategy for enhancing Raman signals via analyte enrichment, plasmonic resonance, and reamplification by microsphere.•Heating-evaporation-assisted superhydrophobic/-philic substrates enable efficient localization and enrichment of analytes.•Dielectric microspheres further enhance surface-enhanced Raman scattering signals by two orders of magnitude.•The constructed sensing platform detects femtomolar concentrations of rhodamine 6 G molecules and harmful fish drugs.