Hydrophobic Paper-Based SERS Sensor Using Gold Nanoparticles Arranged on Graphene Oxide Flakes

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.

UV Irradiation-Induced SERS Enhancement in Randomly Distributed Au Nanostructures

“…Figure 3 a shows the Raman spectrum of the Au4.5 sample annealed at RT. This spectrum shows strong peaks of the vibrational bands at approximately 611, 773, 1310, 1363, and 1651 cm −1 , corresponding to the Raman characteristic peaks of R6G [ 32 , 33 , 34 ]. The vibrational band at 611 cm −1 is due to the in-plane and out-of-plane xanthene ring deformations.…”

A Review of Graphene-Based Surface Plasmon Resonance and Surface-Enhanced Raman Scattering Biosensors: Current Status and Future Prospects

“…There is another technique in which the Raman signal does not depend on the substrate but on the molecular analyte. By taking advantage of the increased probability of the Raman transition when the analyte is absorbed, this technique is known as chemical enhancement [104][105][106]. Graphene has been shown to be a very outstanding SERS active substrate due to its advantages over other traditional materials.…”

3D Hotspot Matrix of Au Nanoparticles on Au Nanostructures with a Spacer Layer of Dithiol Molecules for Highly Sensitive Surface-Enhanced Raman Spectroscopy

“…For monitoring of SERS behaviors to R6G, AuNSs samples and AuNP@BDMT@AuNSs samples were dipped in an aqueous solution of R6G with different concentrations ranging from 10 µM to 1 nM for 1 h, as described in our previous studies 28, 39 . The samples were then rinsed in Milli-Q water and dried with a nitrogen blow to remove the un xed molecules.…”