Hotspot-type silver-polymers grafted nanocellulose paper with analyte enrichment as flexible plasmonic sensors for highly sensitive SERS sensing

Abstract

High order plasmonic types by integrating a novel heterogeneous plasmonic and flexible model based on the co-existence of Ag nanospheres (NSs) and Ag nanocubes (NCs) are introduced. The point-to-facet type in these hybrid shapes produces surface-enhanced Raman scattering (SERS) signals many-fold larger than in single-plasmonic constructs. A high enhancement factor (EF = 4.6 × 108) in coupled plasmonic particulates allowed SERS-probing at ultralow sample quantities. Then, these plasmonic constructs are anchored onto a flexible polymethyl methacrylate (PMMA)-treated cellulose paper. In addition to strong electromagnetic enhancement, the hydrophobic surface could concentrate target analytes in the hotspot areas, resulting in highly active SERS responses in highly diluted solutions. As a result, the flexible SERS sensing platform exhibits high sensitivity with detection around 10−10 M and point-to-face relative standard deviation (RSD) in one sensor as low as 7.28%, thereby demonstrating good reproducibility. Furthermore, it exhibits perfectly selective detection for trace amounts of interest analytes in a complex solution, significantly enhancing the analyte identification efficiency at nanomolar concentration levels. This study has proven a promising route for an integrated SERS platform with plasmonic nanoconstructs and analyte enrichment as a versatile SERS sensor for highly sensitive, quantitative, selective, and cost-effective SERS detection.

Keywords

• SERS
• Analyte enrichment
• Hotspot type
• Hybrid shape self-assembly
• Polymers