Monolithically integrated microfluidic nanoporous gold disk (NPGD) surface-enhanced Raman scattering (SERS) sensor for rapid and label-free biomolecular detection

Ming Li, Fusheng Zhao, Jianbo Zeng, Greggy M. Santos, Wei-Chuan Shih

Research output: Chapter in Book/Report/Conference proceedingConference contributionResearchpeer-review

Abstract

We present a novel microfluidic surface-enhanced Raman scattering (SERS) sensor for rapid and label-free biomolecular detection. Our sensor design mitigates a common limiting factor in microfluidic SERS sensors that utilize integrated nanostructures: low-efficiency transport of biomolecules to nanostructured surface which adversely impacts sensitivity. Our strategy is to increase the total usable nanostructured surface area, which provides more adsorption sites for biomolecules. Specifically, nanoporous gold disk (NPGD) array, a highly effective SERS substrate, has been monolithically integrated inside a microfluidic chip. Individual NPGD is known to feature an order of magnitude larger surface area than its projected disk area. The increased surface area arises from nanoscale pores and ligaments 3- dimensionally distributed in the NPGD, which manifest themselves as high-density SERS hot-spots. High-density NPGD arrays further guarantee large coverage of these hot-spots on the microchannel floor. The SERS-active NPGD arrays enable highly-reproducible SERS measurements with relative intensity variations from 8% to -8%. R6G solutions in the concentrations ranging from 1 μM to 1 mM have been detected and quantitatively evaluated, and the performance of the sensor in continuous-flow condition has been assessed. Moreover, the sensor’s capabilities have been studied by detecting and identifying a physiological metabolite (urea), and the results show lower detection limit compared to best results from most recent work using integrated nanostructured surface inside microchannels. We expect that the sensor would be applicable for detecting, identifying and quantifying molecules for some point-of-care applications, i.e. urine screening.
Original languageEnglish
Title of host publicationMicrofluidics, BioMEMS, and Medical Microsystems XIII
EditorsBonnie L. Gray, Holger Becker
Place of PublicationBellingham, WA
PublisherSPIE
Pages1-7
Number of pages7
ISBN (Print)9781628414103
DOIs
Publication statusPublished - 2015
Externally publishedYes
EventSPIE Photonics West 2015: Microfluidics, BioMEMS, and Medical Microsystems XIII - San Francisco, United States
Duration: 7 Feb 20159 Feb 2015

Publication series

NameProceedings of SPIE
PublisherSPIE
Volume9320

Conference

ConferenceSPIE Photonics West 2015
CountryUnited States
CitySan Francisco
Period7/02/159/02/15

Keywords

  • Surface-enhanced Raman scattering (SERS)
  • microfluidics
  • nanoporous gold disk (NPGD)
  • biomolecular sensing
  • urea

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    Li, M., Zhao, F., Zeng, J., Santos, G. M., & Shih, W-C. (2015). Monolithically integrated microfluidic nanoporous gold disk (NPGD) surface-enhanced Raman scattering (SERS) sensor for rapid and label-free biomolecular detection. In B. L. Gray, & H. Becker (Eds.), Microfluidics, BioMEMS, and Medical Microsystems XIII (pp. 1-7). [93200K] (Proceedings of SPIE; Vol. 9320). SPIE. https://doi.org/10.1117/12.2078519