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Liquid-Phase Peak Force Infrared Microscopy

preprint
submitted on 31.05.2020 and posted on 02.06.2020 by Haomin Wang, Joseph M. González-Fialkowski, Wenqian Li, Yan Yu, Xiaoji Xu
Atomic force microscopy-infrared microscopy (AFM-IR) provides a route to bypass Abbe’s diffraction limit through photothermal detections of infrared absorption. With the combination of total internal reflection, AFM-IR can operate in the aqueous phase. However, AFM-IR in contact mode suffers from surface damage from the lateral shear force between the tip and sample, and can only achieve 20~25-nm spatial resolution. Here, we develop the liquid-phase peak force infrared (LiPFIR) microscopy that avoids the detrimental shear force and delivers an 8-nm spatial resolution. The non-destructiveness of the LiPFIR microscopy enables in situ chemical measurement of heterogeneous materials and investigations on a range of chemical and physical transformations, including polymer surface reorganization, hydrogen-deuterium isotope exchange, and ethanol-induced denaturation of proteins. We also perform LiPFIR imaging of the budding site of yeast cell wall in the fluid as a demonstration of biological applications. LiPFIR unleashes the potential of in liquid AFM-IR for chemical nanoscopy.

History

Email Address of Submitting Author

haw515@lehigh.edu

Institution

Lehigh University

Country

United States

ORCID For Submitting Author

0000-0001-7193-8651

Declaration of Conflict of Interest

No conflict of interest

Version Notes

This is the initial version

Exports