Thermo-Optoplasmonic Single-Molecule Sensing on Optical Microcavities

Nikita A. Toropov, Matthew C. Houghton, Deshui Yu, Frank Vollmer

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)

Abstract

Whispering-gallery-mode (WGM) resonators are powerful instruments for single-molecule sensing in biological and biochemical investigations. WGM sensors leveraged by plasmonic nanostructures, known as optoplasmonic sensors, provide sensitivity down to single atomic ions. In this article, we describe that the response of optoplasmonic sensors upon the attachment of single protein molecules strongly depends on the intensity of WGM. At low intensity, protein binding causes red shifts of WGM resonance wavelengths, known as the reactive sensing mechanism. By contrast, blue shifts are obtained at high intensities, which we explain as thermo-optoplasmonic (TOP) sensing, where molecules transform absorbed WGM radiation into heat. To support our conclusions, we experimentally investigated seven molecules and complexes; we observed blue shifts for dye molecules, amino acids, and anomalous absorption of enzymes in the near-infrared spectral region. As an example of an application, we propose a physical model of TOP sensing that can be used for the development of single-molecule absorption spectrometers.

Original languageEnglish
Pages (from-to)17534-17546
Number of pages13
JournalACS Nano
Volume18
Issue number27
Early online date26 Jun 2024
DOIs
Publication statusPublished - 9 Jul 2024
Externally publishedYes

Funding

The authors acknowledge funding from UKRI Engineering and Physical Sciences Research Council [EP/T002875/1]. M.C.H. acknowledges funding from the UKRI Biotechnology and Biological Sciences Research Council-funded South West Biosciences Doctoral Training Partnership [BB/T008741/1].

FundersFunder number
Engineering and Physical Sciences Research CouncilEP/T002875/1
Engineering and Physical Sciences Research Council
UKRI CDT in Accountable, Responsible and Transparent AIBB/T008741/1

Keywords

  • absorption
  • microresonator
  • plasmon
  • protein
  • sensor
  • tryptophan

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy

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