Extremely Sensitive SERS Sensors Based on a Femtosecond Laser-Fabricated Superhydrophobic/-philic Microporous Platform

The detection of molecules from highly diluted solutions with a limited amount is vital for precancer diagnosis, food safety, and forensic analysis. The sensitivity and convenience of detection techniques are the primary concerns. In this study, a hybrid superhydrophobic/-philic (SH/SHL) microporous platform is designed and fabricated by a femtosecond laser to improve surface-enhanced Raman scattering (SERS) performances. Relying on the micropores fabricated at the center of SHL patterns, sediments distributed at the central regions are avoided, leading to the further enrichment of the target molecules. The engineered micropores with high identification further improve the speed of Raman tests, and the fabricated SERS substrate shows an advantage in outdoor handheld detection and automated inspection applications. The optimized SERS sensor is sufficient for attomolar-level detection (10-17 M) of rhodamine 6G using analyte volumes of just 5 μL, corresponding to an enhancement factor of 5.19 × 1013. Meanwhile, a relative standard deviation of 7.48% at 10-10 M shows the excellent uniformity of this proposed SERS platform. This work further pushes forward the practical applications of SERS technology in ultratrace molecular detections.