Development of a MoS2/Ag NP Nanopocket to Trap Target Molecules for Surface-Enhanced Raman Scattering Detection with Long-Term Stability and High Sensitivity

Surface-enhanced Raman scattering (SERS) substrates mostly achieve highly sensitive detection by designing various hot spots; however, how to guide molecules to hot spots and prevent them from leaving has not been thoroughly considered and studied. Here, a composite MoS2/Ag NP nanopocket detector composed of MoS2 covered with a Ag NP film was fabricated to develop a general SERS method for actively capturing target molecules into hotspots. A finite element method (FEM) simulation of the multiphysics model was used to analyze the distributions of electric field enhancements and hydrodynamic processes in solution and air of the MoS2/Ag NP nanopocket. The results revealed that covering MoS2 slowed the evaporation of the solution, extended the window period for SERS detection, and enhanced the electric field in comparison with the monolayer Ag NP film. Therefore, in the process of dynamic detection, the MoS2/Ag NP nanopocket can provide an efficient and stable signal within 8 min, increasing the high sensitivity and long-term stability of the SERS method. Furthermore, a MoS2/Ag NP nanopocket detector was applied to detect antitumor drugs and monitor hypoxanthine structural changes in serum, which demonstrated long-term stability and high sensitivity for SERS analysis. This MoS2/Ag NP nanopocket detector paves the way for developing the SERS method in various fields.