TY - JOUR
AU - Brian O’Callahan
AU - Kyoung-Duck Park
AU - Irina Novikova
AU - Tengyue Jian
AU - Chun-Long Chen
AU - Eric Muller
AU - Patrick El-Khoury
AU - Markus Raschke
AU - Scott Lea
AB - Imaging heterogeneous 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 nano-imaging in liquid based on infrared scattering scanning near-field optical microscopy (IR s-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 s-SNOM vibrational nano-imaging and conformational identification of catalase nano-crystals 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 in-situ IR s-SNOM spectroscopic chemical nano-imaging and its general applicability to bio-molecular, cellular, catalytic, electrochemical, or other interfaces and nano-systems in liquids or solutions.
BT - Nano Letters
DA - 2020-05
DO - 10.1021/acs.nanolett.0c01291
IS - 6
M1 - ja
N1 - PMID: 32356991
N2 - Imaging heterogeneous 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 nano-imaging in liquid based on infrared scattering scanning near-field optical microscopy (IR s-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 s-SNOM vibrational nano-imaging and conformational identification of catalase nano-crystals 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 in-situ IR s-SNOM spectroscopic chemical nano-imaging and its general applicability to bio-molecular, cellular, catalytic, electrochemical, or other interfaces and nano-systems in liquids or solutions.
PY - 2020
EP - 4497–4504
T2 - Nano Letters
TI - In liquid infrared scattering scanning near-field optical microscopy for chemical and biological nano-imaging
UR - https://doi.org/10.1021/acs.nanolett.0c01291
VL - 20
ER -