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Liquid-Phase Peak Force Infrared Microscopy

revised on 13.10.2020 and posted on 14.10.2020 by Haomin Wang, Joseph M. González-Fialkowski, Wenqian Li, Qing Xie, 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.


Email Address of Submitting Author


Lehigh University


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

No conflict of interest

Version Notes

This is the initial version