Millimeter-sized suspended plasmonic nanohole arrays for surface-tension-driven flow-through SERS

Shailabh Kumar, Sudhir Cherukulappurath, Timothy W. Johnson, Sang Hyun Oh

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

We present metallic nanohole arrays fabricated on suspended membranes as an optofluidic substrate. Millimeter-sized suspended nanohole arrays were fabricated using nanoimprint lithography. We demonstrate refractive-index-based tuning of the optical spectra using a sucrose solution for the optimization of SERS signal intensity, leading to a Raman enhancement factor of 107. Furthermore, compared to dead-ended nanohole arrays, suspended nanohole arrays capable of flow-through detection increased the measured SERS signal intensity by 50 times. For directed transport of analytes, we present a novel methodology utilizing surface tension to generate spontaneous flow through the nanoholes with flow rates of 1 μL/min, obviating the need for external pumps or microfluidic interconnects. Using this method for SERS, we obtained a 50 times higher signal as compared to diffusion-limited transport and could detect 100 pM 4-mercaptopyridine. The suspended nanohole substrates presented herein possess a uniform and reproducible geometry and show the potential for improved analyte transport and SERS detection.

Original languageEnglish (US)
Pages (from-to)6523-6530
Number of pages8
JournalChemistry of Materials
Volume26
Issue number22
DOIs
StatePublished - Nov 25 2014

Bibliographical note

Publisher Copyright:
© 2014 American Chemical Society.

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