Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment
- Authors
- Type
- Published Article
- Journal
- ACS Nano
- Publisher
- American Chemical Society
- Publication Date
- Aug 16, 2015
- Volume
- 9
- Issue
- 8
- Pages
- 7968–7975
- Identifiers
- DOI: 10.1021/acsnano.5b01184
- Source
- LIBNA
- Keywords
- License
- Green
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).
