These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 31.05.2020 and posted on 02.06.2020by 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.