Abstract

Paper-based surface-enhanced Raman scattering (SERS) sensors have garnered much attention in the past decade owing to their ubiquity, ease of fabrication, and environmentally friendly substrate. The main drawbacks of a paper substrate for a SERS sensor are its high porosity, inherent hygroscopic nature, and hydrophilic surface property, which reduce the sensitivity and reproducibility of the SERS sensor. Here, we propose a simple, quick, convenient, and economical method for hydrophilic to hydrophobic surface modification of paper, while enhancing its mechanical and moisture-resistant properties. The hydrophobic paper (h-paper) was obtained by spin-coating diluted polydimethylsiloxane (PDMS) solution onto the filter paper, resulting in h-paper with an increased contact angle of up to ≈130°. To complete the h-paper-based SERS substrate, gold nanoparticles arranged on graphene oxide (AuNPs@GO) were synthesized using UV photoreduction, followed by drop-casting of AuNPs@GO solution on the h-paper substrate. The enhancement of the SERS signal was then assessed by attaching a rhodamine 6G (R6G) molecule as a Raman probe material to the h-paper-based SERS substrate. The limit of detection was 10 nM with an R2 of 0.966. The presented SERS sensor was also tested to detect a thiram at the micromolar level. We expect that our proposed AuNPs@GO/h-paper-based SERS sensor could be applied to point-of-care diagnostics applications in daily life and in spacecraft.

Highlights

  • Surface-enhanced Raman scattering (SERS) is a crucial tool for the analysis of molecule traces since the accidental discovery of the enhancement of Raman scattering signals upon Ag-roughened surfaces [1]

  • The dominant mechanism of surface-enhanced Raman scattering (SERS) is characterized by locally enhanced electromagnetic (EM) fields occurring in the vicinity of the metal nanostructures owing to the localized surface plasmon resonances (LSPRs) [2,3,4]

  • Raman scattering signal for the proposed SERS substrates, the AuNPs@graphene oxide (GO)/h-paper substrates were soaked in rhodamine 6G (R6G) in deionized (DI) water and thiram in ethanol of varying concentrations for 1 h

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Summary

Introduction

Surface-enhanced Raman scattering (SERS) is a crucial tool for the analysis of molecule traces since the accidental discovery of the enhancement of Raman scattering signals upon Ag-roughened surfaces [1]. We propose a simple, convenient, timesaving, and economical method for hydrophobic surface modification of the filter paper and demonstrate the h-paper-based SERS sensor composed of gold nanoparticles arranged on graphene oxide (AuNPs@GO) flakes on the h-paper SERS substrate. To fabricate a stable metal-nanoparticle platform, graphene oxide (GO) was used as a support for the arrangement of AuNPs. Graphene and graphene-based substrates are considered a promising material for SERS sensors owing to their large surface area and excellent molecule adsorption ability, and a number of graphene-based SERS devices have been proposed [7,18,19,20,21,22,23,24,25,26]. We investigated the presented SERS sensor to detect a thiram at the micromolar level

Materials and Reagents
Fabrication of the h-Paper-Based SERS Sensor
Characterization and Measurements
Results and Discussionof
Conclusions
Full Text
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