Construction of flexible, transparent and mechanically robust SERS-active substrate with an efficient spin coating method for rapid in-situ target molecules detection

Abstract

Flexible, transparent and mechanically robust surface enhanced Raman scattering (SERS)-active substrates is currently the most attractive research focus in the field of Raman detection, and also a powerful analysis and identification technique in the biological research. Herein, we introduced a low-cost and large-scale method to fabricate flexible and transparent AgNPs/WPU plasmonic metafilm with monolayer-island phase nanostructures based on silver nanoparticles (AgNPs) and waterborne polyurethane emulsion (WPU) film. The obtained AgNPs/WPU plasmonic metafilm demonstrated excellent SERS sensitivity, signal uniformity and reproducibility, and the SERS substrates could still maintain excellent stability even after being bent or stretched over 100 cycles. The detection concentration was as low as 10 -9 M with 4-Mercaptobenzoic acid (4-MBA) as probe molecule, and the enhancement factor was high to 2.2×10 7 . More importantly, the flexibility and adhesivity of AgNPs/WPU plasmonic metafilm could be directly conformal coverage on the apple surface for in situ detection of thiram residue, and the detection limit was as low as 9.0165 ng cm −2 . This versatile AgNPs/WPU plasmonic metalfilm would be a promising SERS substrate for the detection of pesticide residue in chemical and biological applications.

Rapid Detection of Malathion, Phoxim and Thiram on Orange Surfaces Using Ag Nanoparticle Modified PDMS as Surface-Enhanced Raman Spectroscopy Substrate

“…The linear calibration plots of all three pesticides are also illustrated in Figure 4 b,d,f, respectively. SERS detection of thiram has been extensively studied in previous reports [ 38 , 40 , 43 , 44 ]. In this study, thiram was chosen first for pesticide detection.…”

“…Apart from metal foils, polymer films have also been studied to fabricate flexible substrates for SERS [ 39 ]. Bai et al spin-coated a monolayer of Ag island on a waterborne polyurethane emulsion film and applied the substrate for in-situ detection of thiram on apples [ 40 ]. In another study, a flexible Au nanostars/polydimethylsiloxane (PDMS) substrate was recently developed for in-situ determination of methyl parathion on fruit [ 41 ].…”

Applications of surface‐enhanced Raman spectroscopy in environmental detection

“…While the toxicity of most fungicides is generally low, prolonged exposure to these compounds may lead to adverse health effects such as neurological disruptions 126 . Several recent studies have utilized SERS to detect various fungicides, including tetramethylthiuram disulfide (THR), 39,53,61,70,79,127–161 carbendazim, 162–165 chlorothalonil, 166,167 MG, 168–173 TBZ (a fungicide and parasiticide) 20,79,153,155,173–178 and ferbam 20,178,179 . Among them, THR is the most studied due to its wide agricultural applications and strong binding with SERS nanosubstrates through the thiol group.…”

“…While THR is able to protect fruits and vegetables from fungal diseases that may destroy the plants, it also causes skin and mucosal disease in humans 140,180,181 . Numerous recent studies focus on the detection of THR using SERS methods 39,53,61,70,79,127–161 . While we cannot cover each of these references in detail, a few are expanded upon below.…”

An anti-scratch flexible SERS substrate for pesticide residue detection on the surface of fruits and vegetables

“…The surface microstructures are easily damaged during wipe sampling. Therefore, many efforts have been made to enhance the mechanical robustness of such flexible SERS substrate [29][30][31][32]. Samir Kumar et al reported a robust and flexible SERS substrate, using polydimethylsiloxane (PDMS) film to embed Ag nanorods array to improve the mechanical stability of the substrate, and the Raman signal intensity decreases by only 10% after the substrate is subjected to a tensile strain of 30% [29].…”