双金属双硅层核-壳纳米结构Au@SiO₂@Ag@SiO₂用于葡萄糖检测

Surface-enhanced Raman scattering(SERS) was demonstrated as a highly efficient approach for the amplification of extremely low signals due to the strong electromagnetic field enhancement that occurs near closely-packed metallic nanostructures, which was dependent on the unique localized surface plasmon resonance(LSPR). To develop sensitive SERS probes, different geometric configurations as approaches are focusing on the synthesis of advanced nanostructures, or efficient Raman label compounds that are resonant with excitation light. These geometric factors affect the polarization direction and magnitude of plasmonic coupling and the SERS signal intensity. As we know, plasmonic properties of Au and Ag NPs are highly sensitive to their shapes. In order to improve the performance of metal nanoparticles in SERS detection, we prepared a highly sensitive and stable bimetallic double silicon core-shell nanostructured material of Au@SiO₂@Ag@SiO₂. The nanoparticles have good Raman scattering properties and excellent stability, since the silicon layer between the bimetals promotes remote plasma excitation transfer. The main component of human urine can be directly detected by using this SERS active material, and the material exhibits the ability to detect highly effectiveness 10^-6 mol/L glucose with label-free Au@SiO₂@Ag@SiO₂ nanoparticles. In addition, simultaneous detection of medium concentrations of 10^-3 mol/L glucose and urea molecules in artificial urine and detection of 10^-3 mol/L glucose in actual urine were also achieved. The Au@SiO₂@Ag@SiO₂ nanoparticles show the potential for detection glucose in the presence of multiple biomolecules.