Construct high-precise SERS sensor by hierarchical superhydrophobic Si/Cu(OH)2 platform for ultratrace detection of food contaminants

Abstract

Construction of the high-quality noble metal nanoparticle cluster (NMNPC) with big size for surface-enhanced Raman spectrum is still a challenge nowadays, due to its difficulty in integration of the uniformity, repeatability and sensibility. To realize this goal, a superhydrophobic platform composed of hierarchical Si/Cu(OH)2 nanowires with stable Cassie state was designed and prepared in this work. The optimal Ag NPC region is larger than 0.6 mm × 0.6 mm, and the limit of detection and relative standard deviation of it are respectively 2 × 10−18 M and 13.85%, indicating the fine SERS performance of it. Finite difference time domain simulations and systematic experimental analysis were made in detail here to figure out the underlying mechanism behind these phenomena. Furthermore, as a proof of concept, the Ag NPC was proved as an outstanding food contaminant sensor and successfully realized an ultratrace detection of both melamine in milk and malachite green on fish surface (ca 10−15 M, approaching to single-molecule level). This work provides a new way in constructing high-performance SERS substrate and shows promising application prospect in food safety inspection.