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Issue 11, 2018
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PEGylated nanographene-mediated metallic nanoparticle clusters for surface enhanced Raman scattering-based biosensing

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Abstract

Surface-enhanced Raman scattering (SERS) is an optical spectroscopy technique that can detect a variety of analytes with high sensitivity and selectivity without any labels. Controlled clustering of metallic nanoparticles to prepare a new class of SERS nanotags is crucial for the ultra-sensitive detection of specific biological and chemical moieties because increased plasmonic hotspot junctions produce a greatly enhanced SERS signal. We report herein that controlled clustering of Au nanoparticles (AuNPs) was mediated by PEGylated nano-sized graphene (PNG) and that the PNG-induced AuNP clusters (PNG-AuNPCs) were highly sensitive SERS nanotags with colloidal stability for SERS-based biosensing. The AuNPs labeled with 4-mercaptopyridine as a Raman reporter were surface-modified with 1-aminomethylpyrene for the introduction of hydrophobic moieties, and were non-covalently complexed with PNG via π–π stacking and van der Waals forces. It resulted in the formation of PNG-AuNPCs that increased SERS intensity with an enhancement factor of 1.34 × 1011. The PNG induced a high degree of AuNP clustering by enhancing the non-covalent interactions between them, resulting in increased hotspot junctions at highly localized plasmonic centers. Furthermore, to show that the PNG-AuNPCs would serve as stable, reproducible, and highly sensitive SERS nanotags for biosensing, we formed sandwich-type immunocomplexes composed of the PNG-AuNPCs, immunoglobulin G (IgG) as the antigen, and magnetic beads. We found a linear relationship between SERS intensity and IgG concentration, with a limit of detection lower than 31.0 fM for IgG detection. Thus, the PNG-AuNPCs could be useful as SERS nanotags for highly sensitive SERS-based biosensing applications.

Graphical abstract: PEGylated nanographene-mediated metallic nanoparticle clusters for surface enhanced Raman scattering-based biosensing

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Publication details

The article was received on 21 Feb 2018, accepted on 10 Apr 2018 and first published on 10 Apr 2018


Article type: Paper
DOI: 10.1039/C8AN00329G
Citation: Analyst, 2018,143, 2604-2615
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    PEGylated nanographene-mediated metallic nanoparticle clusters for surface enhanced Raman scattering-based biosensing

    A. Ali, E. Y. Hwang, J. Choo and D. W. Lim, Analyst, 2018, 143, 2604
    DOI: 10.1039/C8AN00329G

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