title: Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment.
abstract: Scattering scanning near-field optical microscopy (s-SNOM) has emerged as a powerful nanoscale spectroscopic tool capable of characterizing individual biomacromolecules and molecular materials. However, applications of scattering-based near-field techniques in the infrared (IR) to native biosystems still await a solution of how to implement the required aqueous environment. In this work, we demonstrate an IR-compatible liquid cell architecture that enables near-field imaging and nanospectroscopy by taking advantage of the unique properties of graphene. Large-area graphene acts as an impermeable monolayer barrier that allows for nano-IR inspection of underlying molecular materials in liquid. Here, we use s-SNOM to investigate the tobacco mosaic virus (TMV) in water underneath graphene. We resolve individual virus particles and register the amide I and II bands of TMV at ca. 1520 and 1660 cm(-1), respectively, using nanoscale Fourier transform infrared spectroscopy (nano-FTIR). We verify the presence of water in the graphene liquid cell by identifying a spectral feature associated with water absorption at 1610 cm(-1).
authors.affiliation: Department of Physics, Department of Chemistry, and JILA, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Omar
authors.initials: O
authors.lastname: Khatib
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Wood
authors.forename: Alexander S
authors.initials: AS
authors.lastname: McLeod
authors.forename: Michael D
authors.initials: MD
authors.lastname: Goldflam
authors.forename: Martin
authors.initials: M
authors.lastname: Wagner
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Damhorst
authors.forename: Justin C
authors.initials: JC
authors.lastname: Koepke
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Doidge
authors.forename: Aniruddh
authors.initials: A
authors.lastname: Rangarajan
authors.forename: Rashid
authors.initials: R
authors.lastname: Bashir
authors.affiliation: Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Pop
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Lyding
authors.forename: Mark H
authors.initials: MH
authors.lastname: Thiemens
authors.affiliation: Ludwig-Maximilians-Universität and Center for Nanoscience , 80539 München, Germany.
authors.forename: Fritz
authors.initials: F
authors.lastname: Keilmann
authors.forename: D N
authors.initials: DN
authors.lastname: Basov
mesh_terms: D006108:Graphite / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation* / Q000379:methods; D014027:Tobacco Mosaic Virus / Q000648:ultrastructure; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D006108:Graphite
keywords: biomaterials; infrared nanospectroscopy; nanoimaging; near-field; s-SNOM; water