High-sensitivity SERS detection via heated evaporation enrichment on superhydrophobic/hydrophilic substrates coupled with microspheres

This work focuses on the highly sensitive and rapid detection of target molecules from small samples through surface-enhanced Raman scattering (SERS). By creating patterned surfaces with adhesion differences using femtosecond laser, we successfully achieved rapid localization of target droplets. The coupling enhancement between the Photonic Nanojets (PNJs) generated by dielectric microspheres and the Localized Surface Plasmon Resonances (LSPRs) generated by metallic nanostructures provides a synergistic enhancement mode produced by hybrid multi-scale structures for high-sensitivity Raman detection. Moreover, to overcome the prolonged evaporation time of droplets on superhydrophobic surfaces, we utilized the Leidenfrost effect to aid evaporation. Compared to natural evaporation, this strategy can overcome diffusion limitations in SERS measurements, allowing diluted analyte molecules to rapidly concentrate within a very short time, and significantly reducing the deposition area of the analyte. The new method of SERS sensing, which involves enriching analytes through heating-evaporation on superhydrophobic/hydrophilic (SH/SHL) substrates and combining them with microspheres, demonstrates a rapid and ultrasensitive biochemical detection strategy, potentially paving the way for future automation in Raman detection.