Ultrasensitive Mid-Infrared Biosensing in Aqueous Solutions with Graphene Plasmons

Chenchen Wu, Xiangdong Guo, Yu Duan, Wei Lyu, Hai Hu, Debo Hu, Ke Chen, Zhipei Sun, Teng Gao, Xiaoxia Yang*, Qing Dai

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

34 Citations (Scopus)
155 Downloads (Pure)

Abstract

Identifying nanoscale biomolecules in aqueous solutions by Fourier transform infrared spectroscopy (FTIR) provides an in situ and noninvasive method for exploring the structure, reactions, and transport of biologically active molecules. However, this remains a challenge due to the strong and broad IR absorption of water which overwhelms the respective vibrational fingerprints of the biomolecules. In this work, a tunable IR transparent microfluidic system with graphene plasmons is exploited to identify approximate to 2 nm-thick proteins in physiological conditions. The acquired in situ tunability makes it possible to eliminate the IR absorption of water outside the graphene plasmonic hotspots by background subtraction. Most importantly, the ultrahigh confinement of graphene plasmons (confined to approximate to 15 nm) permits the implementation of nanoscale sensitivity. Then, the deuterium effects on monolayer proteins are characterized within an aqueous solution. The tunable graphene-plasmon-enhanced FTIR technology provides a novel platform for studying biological processes in an aqueous solution at the nanoscale.

Original languageEnglish
Article number2110525
Number of pages8
JournalAdvanced Materials
Volume34
Issue number27
Early online date29 May 2022
DOIs
Publication statusPublished - 7 Jul 2022
MoE publication typeA1 Journal article-refereed

Keywords

  • aqueous solutions
  • biosensing
  • graphene plasmons
  • surface-enhanced infrared spectroscopy

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