title: Nano-chemical infrared imaging of membrane proteins in lipid bilayers.
abstract: The spectroscopic characterization of biomolecular structures requires nanometer spatial resolution and chemical specificity. We perform full spatio-spectral imaging of dried purple membrane patches purified from Halobacterium salinarum with infrared vibrational scattering-type scanning near-field optical microscopy (s-SNOM). Using near-field spectral phase contrast based on the Amide I resonance of the protein backbone, we identify the protein distribution with 20 nm spatial resolution and few-protein sensitivity. This demonstrates the general applicability of s-SNOM vibrational nanospectroscopy, with potential extension to a wide range of biomolecular systems.
authors.affiliation: Department of Physics and Department of Chemistry, ‡Department of Chemical and Biological Engineering, and §Department of Molecular, Cellular, and Developmental Biology, University of Colorado , Boulder, Colorado, 80309, United States.
authors.forename: Samuel
authors.initials: S
authors.lastname: Berweger
authors.forename: Duc M
authors.initials: DM
authors.lastname: Nguyen
authors.forename: Eric A
authors.initials: EA
authors.lastname: Muller
authors.forename: Hans A
authors.initials: HA
authors.lastname: Bechtel
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Perkins
authors.forename: Markus B
authors.initials: MB
authors.lastname: Raschke
mesh_terms: D008051:Lipid Bilayers; D008565:Membrane Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins