Abstract
Noble metal nanostructures have been intensively investigated as active substrates for surface-enhanced Raman spectroscopy (SERS) from visible to near-IR wavelengths. However, metal nanoparticle-based SERS analysis in solutions is very challenging due to uncontrollable and irreproducible colloid aggregation. Here we report the templated synthesis of porous gold-silica hybrid microspheres and their application as reusable colloidal SERS substrates. Mesoporous polymer microspheres are synthesized and used as templates for the synthesis of non-aggregated gold nanoparticles, followed by polydopamine-mediated silicification to fabricate mesoporous gold-silica hybrid microspheres. The mesoporous hybrid particles detect crystal violet in the order of 10–8 M and provide the structural durability of the immobilized gold nanoparticles, allowing them to be recycled for repeated SERS analyses for analytes in a solution with the similar sensitivity. This work suggests that the mesoporous gold-silica hybrid microspheres are attractive SERS substrates in terms of reusability, sensitivity, and stability.
Highlights
By the difficulty of the formation of controllable and reproducible hotspots in colloidal systems
Porous poly(ethylene glycol dimethacrylate-co-acrylonitrile) (poly(EGDMA-co-AN)) microspheres were synthesized by suspension polymerization and used as an architecture template for the in situ synthesis of AuNPs and a silica matrix[33,35]
Microspheres were synthesized by suspension polymerization using toluene as a porogen according to our previous reports[33,35]
Summary
HoYeon Son[1], Kyeong Rak Kim 1, Jun Bae Lee[2,3], Trang Huyen Le Kim[1], Jihui Jang[2], Su Ji Kim[2], Moung SeokYoon[2], Jin Woong Kim3,4 &Yoon Sung Nam 1,5. This synthetic scheme enables the synthesis of gold nanostructures on the surface of nanoscale pores of silica microparticles, which are clearly different from gold nanostructures encapsulated within a silica shell. We examined different procedures and compositions to control the structural properties of the gold-silica hybrid microspheres and evaluated their applicability as reusable colloidal SERS substrates using crystal violet (CV) as a model analyte in a solution
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