Nano-chemical infrared imaging of membrane proteins in lipid bilayers
Samuel Berweger1, Duc M Nguyen, Eric A Muller
1Department 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.
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.
