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Enhanced broadband fluorescence detection of nucleic acids using multipolar gap-plasmons on biomimetic Au metasurfaces

Narasimhan, Vinayak and Siddique, Radwanul Hasan and Hoffmann, Magnus and Kumar, Shailabh and Choo, Hyuck (2019) Enhanced broadband fluorescence detection of nucleic acids using multipolar gap-plasmons on biomimetic Au metasurfaces. Nanoscale, 11 (29). pp. 13750-13757. ISSN 2040-3364. doi:10.1039/c9nr03178b.

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Recent studies on metal–insulator–metal-based plasmonic antennas have shown that emitters could couple with higher-order gap-plasmon modes in sub-10-nm gaps to overcome quenching. However, these gaps are often physically inaccessible for functionalization and are not scalably manufacturable. Here, using a simple biomimetic batch-fabrication, a plasmonic metasurface is created consisting of closely-coupled nanodisks and nanoholes in a metal–insulator–metal arrangement. The quadrupolar mode of this system exhibits strong broadband resonance in the visible-near-infrared regime with minimal absorptive losses and effectively supresses quenching, making it highly suitable for broadband plasmon-enhanced fluorescence. Functionalizing the accessible insulator nanogap, analytes are selectively immobilized onto the plasmonic hotspot enabling highly-localized detection. Sensing the streptavidin–biotin complex, a 91-, 288-, 403- and 501-fold fluorescence enhancement is observed for Alexa Fluor 555, 647, 750 and 790, respectively. Finally, the detection of single-stranded DNA (gag, CD4 and CCR5) analogues of genes studied in the pathogenesis of HIV-1 between 10 pM–10 μM concentrations and then CD4 mRNA in the lysate of transiently-transfected cells with a 5.4-fold increase in fluorescence intensity relative to an untransfected control is demonstrated. This outcome promises the use of biomimetic Au metasurfaces as platforms for robust detection of low-abundance nucleic acids.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Narasimhan, Vinayak0000-0003-4165-402X
Siddique, Radwanul Hasan0000-0001-7494-5857
Hoffmann, Magnus0000-0003-4923-9568
Kumar, Shailabh0000-0001-5383-3282
Choo, Hyuck0000-0002-8903-7939
Additional Information:© 2019 The Royal Society of Chemistry. The article was received on 13 Apr 2019, accepted on 18 May 2019 and first published on 20 May 2019. The authors acknowledge the financial support provided by the SAMSUNG Global Research Outreach (GRO) program. The authors are also thankful for the support and resources provided by the Kavli Nanoscience Institute and the Beckman Institute Biological Imaging Facility at Caltech. There are no conflicts to declare.
Group:Kavli Nanoscience Institute
Funding AgencyGrant Number
SAMSUNG Global Research OutreachUNSPECIFIED
Kavli Nanoscience InstituteUNSPECIFIED
Caltech Beckman InstituteUNSPECIFIED
Issue or Number:29
Record Number:CaltechAUTHORS:20190529-154819907
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95892
Deposited By: Tony Diaz
Deposited On:29 May 2019 22:59
Last Modified:16 Nov 2021 17:16

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