title: Surface enhanced Raman scattering by graphene-nanosheet-gapped plasmonic nanoparticle arrays for multiplexed DNA detection.
abstract: We have developed a new type of surface enhanced Raman scattering (SERS) substrate with thiolated graphene oxide (tGO) nanosheets sandwiched between two layers of closely packed plasmonic nanoparticles. The trilayered substrate is built up through alternative loading of interfacially assembled plasmonic nanoparticle arrays and tGO nanosheets, followed by coating the nanoparticle surfaces with poly(ethylene glycol) (PEG). Here tGO plays multifunctional roles as a 2D scaffold to immobilized interfacially assembled plasmonic nanoparticles, a nanospacer to create SERS-active nanogaps between two layers of nanoparticle arrays, and a molecule harvester to enrich molecules of interest viaπ-π interaction. In particular, the molecule harvesting capability of the tGO nanospacer and the stealth properties of PEG coating on the plasmonic nanoparticles collectively lead to preferential positioning of selective targets such as aromatic molecules and single-stranded DNA at the SERS-active nanogap hotspots. We have demonstrated that an SERS assay based on the PEGylated trilayered substrate, in combination with magnetic separation, allows for sensitive, multiplexed "signal-off" detection of DNA sequences of bacterial pathogens.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457. mbechan@ntu.edu.sg hduan@ntu.edu.sg.
authors.forename: Bo
authors.initials: B
authors.lastname: Duan
authors.forename: Jiajing
authors.initials: J
authors.lastname: Zhou
authors.forename: Zheng
authors.initials: Z
authors.lastname: Fang
authors.forename: Chenxu
authors.initials: C
authors.lastname: Wang
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Wang
authors.forename: Harold F
authors.initials: HF
authors.lastname: Hemond
authors.forename: Mary B
authors.initials: MB
authors.lastname: Chan-Park
authors.forename: Hongwei
authors.initials: H
authors.lastname: Duan
mesh_terms: D004247:DNA / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D011092:Polyethylene Glycols / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: D010087:Oxides; D012834:Silver; D011092:Polyethylene Glycols; D006046:Gold; D006108:Graphite; D004247:DNA