Fabrication of rose-petal-like flexible substrate for rapid sampling and in-situ Raman detection

Abstract

Numerous natural biological materials have been used in surface-enhanced Raman scattering due to the unique properties contributed by their composite structures on the surface, yet the fragility of these materials limits their application prospects. In this study, a rose-petal-like substrate was constructed by imitating the structure of fresh rose petals on the surface of polydimethylsiloxane for direct sampling and in-situ Raman detection. These substrates were created with high precision based on molding the fresh rose petals. The unique three-dimensional structures endow the prepared substrate with excellent hydrophobicity (141.3°) and large specific surface area for holding more hotspots under one laser shot. After loading silver nanoparticles, the substrate exhibited good repeatability (relative standard deviation was 11.5%), and excellent detection limit (10–15 mol·L−1) with rhodamine 6G as the probe molecule. In particular, attributed to its inherent flexibility, the substrate was used for direct sampling and detection of pesticide molecules, such as thiram and methyl parathion, on the apple peels, and the detection limits were found to be 1.8 and 1.2 ng·cm−2, respectively. The results show the ability of the substrate in in-situ sampling and detection, demonstrating significant potential in practical applications.