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-enhancedRaman scattering (SERS) substrates mostly achievehighly sensitive detection by designing various hot spots; however,how to guide molecules to hot spots and prevent them from leavinghas not been thoroughly considered and studied. Here, a compositeMoS(2)/Ag NP nanopocket detector composed of MoS2 covered with a Ag NP film was fabricated to develop a general SERSmethod for actively capturing target molecules into hotspots. A finiteelement method (FEM) simulation of the multiphysics model was usedto analyze the distributions of electric field enhancements and hydrodynamicprocesses in solution and air of the MoS2/Ag NP nanopocket.The results revealed that covering MoS2 slowed the evaporationof the solution, extended the window period for SERS detection, andenhanced the electric field in comparison with the monolayer Ag NPfilm. Therefore, in the process of dynamic detection, the MoS2/Ag NP nanopocket can provide an efficient and stable signalwithin 8 min, increasing the high sensitivity and long-term stabilityof the SERS method. Furthermore, a MoS2/Ag NP nanopocketdetector was applied to detect antitumor drugs and monitor hypoxanthinestructural changes in serum, which demonstrated long-term stabilityand high sensitivity for SERS analysis. This MoS2/Ag NPnanopocket detector paves the way for developing the SERS method invarious fields.