True non-contact atomic force microscopy imaging of heterogeneous biological samples in liquids: topography and material contrast

Almonte, Lisa; Colchero, J.

doi:10.1039/c6nr07967a

Cited by 14 publications

(12 citation statements)

References 51 publications

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“…S1c & S1d). The substantial phase decrease 30 for the triangular areas indicated their chemical transformation. The optical bleaching and disappearance of Raman and photoluminescence peaks characteristic of WS2 (Fig.…”

Section: Resultsmentioning

confidence: 98%

Optically facet-resolved reaction anisotropy in two-dimensional transition metal dichalcogenides

Song¹,

Kang²,

Rhodes³

et al. 2021

2D Mater.

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Anisotropic material properties of two-dimensional (2D) crystals are not only intriguing but also of potential use for many applications. In this work, we report the anisotropy of bond-breaking reactions is governed by the structural anisotropy and significantly material-dependent for 2D semiconducting transition metal dichalcogenides (TMDs). The degree of the anisotropy that led to trigonal oxidation patterns was much higher in MoS2 and MoSe2 than WS2 and WSe2. Using optical second-harmonic generation spectroscopy, we establish crystal-facet-resolved kinetic measurements and show that the reactions proceed fastest (slowest) for chalcogen (metal)-terminated zigzag edges. Edge-specific reaction rates fed into kinetic Wulff construction also verified the material-dependent anisotropy. We also show that the reactions are initiated at substrate-mediated defects that are located on the bottom and top surfaces of 2D TMDs. ASSOCIATED CONTENTSupporting Information. AFM height and phase images of 1L TMDs, Raman and photoluminescence spectra of 3L WS2, determination of crystallographic orientation, complementary AFM images of four multilayer TMDs, TEs in multilayer MoSe2, oxidation patterns predicted by the KWC theory, density of reaction centers, no reactions for WSe2 supported on hBN, size distribution of TOs in 1L WSe2. This material is available free of charge via the Internet at http://pubs.acs.org.

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Section: Resultsmentioning

confidence: 98%

Optically facet-resolved reaction anisotropy in two-dimensional transition metal dichalcogenides

Song¹,

Kang²,

Rhodes³

et al. 2021

2D Mater.

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“…Recently, studies have shown that dynamic AFM allows imaging in a non-contact regime where essentially no forces are applied on the sample. 195 Non-contact imaging eliminates the cellular deformation caused by the mechanical contact from the scanning AFM tip, and thus is a promising way to improve imaging resolution. AFM is capable of probing specific molecular interactions via single-molecule force recognition spectroscopy with the use of functionalized tips.…”

Section: Discussion and Perspectivementioning

confidence: 99%

Nanoscale imaging and force probing of biomolecular systems using atomic force microscopy: from single molecules to living cells

Dang

et al. 2017

Nanoscale

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Due to the lack of adequate tools for observation, native molecular behaviors at the nanoscale have been poorly understood. The advent of atomic force microscopy (AFM) provides an exciting instrument for investigating physiological processes on individual living cells with molecular resolution, which attracts the attention of worldwide researchers. In the past few decades, AFM has been widely utilized to investigate molecular activities on diverse biological interfaces, and the performances and functions of AFM have also been continuously improved, greatly improving our understanding of the behaviors of single molecules in action and demonstrating the important role of AFM in addressing biological issues with unprecedented spatiotemporal resolution. In this article, we review the related techniques and recent progress about applying AFM to characterize biomolecular systems in situ from single molecules to living cells. The challenges and future directions are also discussed.

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“…Again, these requirements cannot be met by most samples or most AFM setups. However, the principle idea that local attractive forces F attr are specific for the local chemical composition and structure (as shown before by ncAFM [15,29] and NF-DAFM [30]) can also be utilized for force spectroscopy under ambient conditions.…”

Section: Introductionmentioning

confidence: 99%

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

Silbernagl

Khorasani

Murillo

et al. 2021

Beilstein J. Nanotechnol.

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A key application of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, k r) of nanoscopic heterogeneous materials. For a complete structure–property correlation, these mechanical measurements are considered to lack the ability to identify the chemical structure of the materials. In this study, the measured attractive force, F attr, acting between the AFM tip and the sample is shown to be an independent measurement for the local chemical composition and hence a complete structure–property correlation can be obtained. A proof of concept is provided by two model samples comprised of (1) epoxy/polycarbonate and (2) epoxy/boehmite. The preparation of the model samples allowed for the assignment of material phases based on AFM topography. Additional chemical characterization on the nanoscale is performed by an AFM/infrared-spectroscopy hybrid method. Mechanical properties (k r) and attractive forces (F attr) are calculated and a structure–property correlation is obtained by a manual principle component analysis (mPCA) from a k r/F attr diagram. A third sample comprised of (3) epoxy/polycarbonate/boehmite is measured by ImAFM. The measurement of a 2 × 2 µm cross section yields 128 × 128 force curves which are successfully evaluated by a k r/F attr diagram and the nanoscopic heterogeneity of the sample is determined.

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True non-contact atomic force microscopy imaging of heterogeneous biological samples in liquids: topography and material contrast

Cited by 14 publications

References 51 publications

Optically facet-resolved reaction anisotropy in two-dimensional transition metal dichalcogenides

Optically facet-resolved reaction anisotropy in two-dimensional transition metal dichalcogenides

Nanoscale imaging and force probing of biomolecular systems using atomic force microscopy: from single molecules to living cells

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

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