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In situ electrochemical regeneration of nanogap hotspots for continuously reusable ultrathin SERS sensors

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Peer-reviewed

Repository DOI


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Authors

Sibug-Torres, Sarah May  ORCID logo  https://orcid.org/0000-0002-6015-4090
Grys, David-Benjamin 
Niihori, Marika 
Wyatt, Elle 

Abstract

jats:titleAbstract</jats:title>jats:pSurface-enhanced Raman spectroscopy (SERS) harnesses the confinement of light into metallic nanoscale hotspots to achieve highly sensitive label-free molecular detection that can be applied for a broad range of sensing applications. However, challenges related to irreversible analyte binding, substrate reproducibility, fouling, and degradation hinder its widespread adoption. Here we show how in-situ electrochemical regeneration can rapidly and precisely reform the nanogap hotspots to enable the continuous reuse of gold nanoparticle monolayers for SERS. Applying an oxidising potential of +1.5 V (vs Ag/AgCl) for 10 s strips a broad range of adsorbates from the nanogaps and forms a metastable oxide layer of few-monolayer thickness. Subsequent application of a reducing potential of −0.80 V for 5 s in the presence of a nanogap-stabilising molecular scaffold, cucurbit[5]uril, reproducibly regenerates the optimal plasmonic properties with SERS enhancement factors ≈10jats:sup6</jats:sup>. The regeneration of the nanogap hotspots allows these SERS substrates to be reused over multiple cycles, demonstrating ≈5% relative standard deviation over at least 30 cycles of analyte detection and regeneration. Such continuous and reliable SERS-based flow analysis accesses diverse applications from environmental monitoring to medical diagnostics.</jats:p>

Description

Acknowledgements: The authors greatly appreciate helpful comments from many colleagues including Oren Scherman, Luis Liz-Marzán, and Duncan Graham. The authors acknowledge financial support from the European Research Council (ERC) under Horizon 2020 research and innovation programme PICOFORCE (Grant Agreement No. 883703), and POSEIDON (Grant Agreement No. 861950) and from the EPSRC (Cambridge NanoDTC EP/L015978/1, EP/L027151/1, EP/X037770/1). S.M.S.-T. is supported by the University of Cambridge Harding Distinguished Postgraduate Scholars Programme. S.M.S.-T., D.-B.G., and N.S. acknowledge support from EPSRC Grant EP/L015889/1 for the EPSRC Centre for Doctoral Training in Sensor Technologies and Applications, and from AstraZeneca (MedImmune Ltd). M.N. is supported by a Gates Cambridge fellowship (OPP1144). B.d.N. acknowledges support from the Royal Society (URF/R1/211162).


Funder: University of Cambridge Harding Distinguished Postgraduate Scholars Programme

Keywords

Journal Title

Nature Communications

Conference Name

Journal ISSN

2041-1723

Volume Title

15

Publisher

Springer Science and Business Media LLC
Sponsorship
EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council) (PICOFORCE (Grant Agreement No. 883703), POSEIDON (Grant Agreement No. 861950))
RCUK | Engineering and Physical Sciences Research Council (EPSRC) (EP/L015978/1, EP/L027151/1, EP/X037770/1, EP/L015889/1, EP/L015889/1, EP/L015889/1)
Gates Cambridge Trust (OPP1144)
Royal Society (URF\R1\211162)