Design and synthesis of a sandwiched silver microsphere/TiO₂ nanoparticles/molecular imprinted polymers structure for suppressing background noise interference in high sensitivity surface-enhanced Raman scattering detection

The combination of surface-enhanced Raman scattering (SERS) with molecular imprinting technology has shown great potential in bioanalysis, medical delivery, and environmental monitoring. However remain, and leakage of imprinting molecule limits detection reliability and sensitivity. Herein, the first time presents an effective strategy to solve this issue. In this case, TiO₂ nanoparticles are employed here to in situ grow on silver microspheres, forming a plasmonic structure. A sandwiched silver microsphere/TiO₂ nanoparticles/molecular imprinted polymers (Ag-TiO₂@MIPs) has obtained by a surface molecular imprinting approach. Remarkably, the unique Ag-TiO₂ plasmonic structures not offer efficient Raman enhancement but also possess excellent photocatalytic activity. By taking advantage of self-cleaning characteristics, the residual template within MIPs matrix can be decomposed by photocatalytic degradation, thereby suppressing interference of background noise and enhancing detection selectivity. Besides, Ag-TiO₂@MIPs with high sensitivity and selectivity in sulfamethazine detection has been demonstrating. The density functional theory calculations have been performed to choose optimal functional monomers and predict Raman spectra of sulfamethazine. Finally, proposed Ag-TiO₂@MIPs for detection of sulfamethazine with good selectivity and recyclability. The minimum detection concentration of sulfamethazine was as low as 3.6 × 10^-9 mol L^-1. Our study points a way for improving the reliability and sensitivity of SERS detection for future practical applications.