Sandwiching analytes with structurally diverse plasmonic nanoparticles on paper substrates for surface enhanced Raman spectroscopy

Abstract

Systematic combination of plasmonic nanoparticles on a paper-based substrate introduces SERS-based signal-enhancement environments via interparticle coupling and hot spots.

3D Silver Dendrites for Single‐molecule Imaging by Surface‐enhanced Raman Spectroscopy

“…[6] An abnormal increase of a Raman signal from analyte molecules is observed when they are adsorbed on or located in a close vicinity to SERS-active substrates. [7] These substrates are important tools of the SERS-spectroscopy and comprise nanoparticles (NPs) of noble metals in colloids [8,9] or immobilized on soft materials including paper, [10][11][12] fabrics, [13,14] polymers, [15,16] plant derivatives [17,18] and the hard ones made of dielectrics [19][20][21] and semiconductors. [22][23][24] Each substrate's type has its own purpose and advantages.…”

Rapid Vertical Flow Assay On Aunp Plasmonic Paper For Sers-Based Point Of Need Diagnostics

“…In this work miRNA was sandwiched between a silver nanoparticle and anisotropic gold nanoparticle. As is evident in ref [61], SERS response of the miRNA sandwiched between a silver nanoparticle and anisotropic gold nanoparticle was substantially greater than miRNA sandwiched between two spherical AuNPs. These results suggest our plasmonic capture substrate should be prepared with anisotropic gold particles and the ERLs should consist of a silver nanoparticle core for even greater enhancement.…”

“…While the dynamic range and overall curve shape, i.e., biding behavior, is similar for each assay, the differences in maximum signal are attributed to differences in the synthesized plasmonic paper substrates responsible for the SERS enhancement. To support this claim, we recently found ~20% variability in SERS signals collected from plasmonic papers [98].…”

“…Second, the AuNP embedded in the paper will form a sandwich-like structure with ERLs bound to captured antigen. This architecture greatly supports plasmonic coupling between the AuNPs to generate a large localized electric field between the sandwiched nanoparticles and significantly enhance the SERS signal relative to the isolated ERL in the absence of plasmonic coupling[98,[109][110][111][112]. In addition to the uniquely designed plasmonic paper to maximize analytical signal, the vertical flow format overcomes diffusional mass transport limitations of traditional immunoassays to substantially reduce assay time and does not suffer from the hook effect, as is the case for lateral flow assays, to improve quantitative capabilities[45].A model antibody-antigen system was employed to establish proof-of-principle for the SERS-based LFA and illustrate the role of the plasmonic capture substrate.…”

“…After completing the reaction, the final solution was adjusted to 80 mL in total volume (exhibiting an extinction maximum of □2.4) and stored at room temperature without further purification prior to use.Preparation of Plasmonic Paper Capture SubstrateWhatman grade 4 and 40 filter paper with 8 and 25 µm pores sizes, respectively, were selected to prepare the plasmonic paper capture substrate. Prepared AuNPs were embedded in the two filter papers using a previously developed dipping method[97][98][99][100]. The papers were first dried at 50 °C in an oven overnight and then immersed in 10 mL of the synthesized AuNP suspension in a plastic petri dishes (60 mm x 15 mm).…”