Ag Nanoparticle-Decorated Graphene Oxide Coatings on the Inner Walls of Optofluidic Capillaries for Real-Time Trace SERS Detection

Abstract

Surface-enhanced Raman scattering (SERS) is a rapid and nondestructive spectroscopic method for trace detection. The enhancement based on both electromagnetic and chemical mechanism requires the molecules to be in close contact with the SERS-active material. Therefore, it is difficult to detect trace amounts of molecules in liquid directly. In this paper, graphene oxide (GO) and Ag nanoparticles (AgNPs) are uniformly modified on the inner wall of the capillary. GO can provide chemical enhancement by adsorbing the analyte onto its flat surface and producing efficient charge transfer resonance with the analyte. AgNPs can provide strong localized surface plasmon resonance for electromagnetic enhancement, while capillary can shorten the molecular enrichment time and provide long light–analyte interaction length. The synergism of GO, AgNPs, and capillary makes the optofluidic platform have the ability of ultrasensitive and real-time detection. The detection limit of Rhodamine 6G and thiram is as low as 10–12 and 10–10 M, respectively, and the enhancement factor is as high as 0.9 × 1010 and 108, which indicates that the SERS-active capillaries have great potentials in real-time ultratrace detection of water environment pollutants.

Plasmonic Ag/ZnO Nanoscale Villi in Microstructure Fibers for Sensitive and Reusable Surface-Enhanced Raman Scattering Sensing

“…The diameter and density of AgNPs were optimized by adjusting the reaction time and the concentration of Ag(NH 3 ) 2+ . Our previous works show that when the reaction time is 3 min and the concentration ratio of Ag(NH 3 ) 2+ to glucose is 2:1, the most suitable deposition density of AgNPs can be obtained . Based on the above reaction parameters, AgNPs were sporadically distributed on ZnO nanorods (Figure S3a, Supporting Information).…”

“…Our previous works show that when the reaction time is 3 min and the concentration ratio of Ag(NH 3 ) 2+ to glucose is 2:1, the most suitable deposition density of AgNPs can be obtained. 29 Based on the above reaction parameters, AgNPs were sporadically distributed on ZnO nanorods (Figure S3a, Supporting Information). After repeating the reaction twice, the number of AgNPs distributed on the top of ZnO nanorods increased significantly, as shown in Figure 1d.…”

Machine Learning-Assisted Pesticide Detection on a Flexible Surface-Enhanced Raman Scattering Substrate Prepared by Silver Nanoparticles

“…Pesticide residues in foods are a serious problem for public health and environment, and it is important to detect them label-free. ,− The high signal enhancement, good homogeneity, and good sample-to-sample repeatability of the green SERS paper are encouraging for its adoption as a sensor platform. Therefore, the platform is used to detect and categorize common pesticides regularly found as pollutants in drinking water.…”

Novel metal enhanced dual-mode fluorometric and SERS aptasensor incorporating a heterostructure nanoassembly for ultrasensitive T-2 toxin detection

“…30–32 GO can interact easily with various organic analyte molecules via π–π stacking to facilitate the transfer of charge from the analyte molecules which makes it an ideal substrate material for various applications in SERS. 6,33,34 The hybridization of plasmonic nanostructures (Au, Ag) with GO has been confirmed for high-performance SERS biosensing and pinpointed Au nanostars (AuNS) as excellent SERS substrates. These heterostructures 35–37 played a pivotal role in the development of dual-mode sensing platforms.…”