Development of a MoS 2 /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 MoS 2 /Ag NP nanopocket detector composed of MoS 2 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 MoS 2 /Ag NP nanopocket. The results revealed that covering MoS 2 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 MoS 2 /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 MoS 2 /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 MoS 2 /Ag NP nanopocket detector paves the way for developing the SERS method in various fields.