In Liquid Infrared Scattering Scanning Near-Field Optical Microscopy for Chemical and Biological Nanoimaging

Imaging biological systems with simultaneous intrinsic chemical specificity and nanometer spatial resolution in their typical native liquid environment has remained a long-standing challenge. Here, we demonstrate a general approach of chemical nanoimaging in liquid based on infrared scattering scann...

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Bibliographic Details
Published in:Nano letters 2020-06, Vol.20 (6), p.4497-4504
Main Authors: O'Callahan, Brian T, Park, Kyoung-Duck, Novikova, Irina V, Jian, Tengyue, Chen, Chun-Long, Muller, Eric A, El-Khoury, Patrick Z, Raschke, Markus B, Lea, A Scott
Format: Article
Language:English
Subjects:
bio-nanoimaging
in-liquid
in-situ
nano-spectroscopy
NANOSCIENCE AND NANOTECHNOLOGY
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Summary:Imaging biological systems with simultaneous intrinsic chemical specificity and nanometer spatial resolution in their typical native liquid environment has remained a long-standing challenge. Here, we demonstrate a general approach of chemical nanoimaging in liquid based on infrared scattering scanning near-field optical microscopy (IR -SNOM). It is enabled by combining AFM operation in a fluid cell with evanescent IR illumination via total internal reflection, which provides spatially confined excitation for minimized IR water absorption, reduced far-field background, and enhanced directional signal emission and sensitivity. We demonstrate in-liquid IR -SNOM vibrational nanoimaging and conformational identification of catalase nanocrystals and spatio-spectral analysis of biomimetic peptoid sheets with monolayer sensitivity and chemical specificity at the few zeptomole level. This work establishes the principles of in-liquid and IR -SNOM spectroscopic chemical nanoimaging and its general applicability to biomolecular, cellular, catalytic, electrochemical, or other interfaces and nanosystems in liquids or solutions.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.0c01291