Atomic force microscopy characterization of corneocytes: effect of moisturizer on their topology, rigidity, and friction

Gaikwad, Ravi; Vasilyev, S.; Datta, Saurabh; Sokolov, Igor

doi:10.1111/j.1600-0846.2010.00446.x

Cited by 11 publications

(11 citation statements)

References 23 publications

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“…This analysis agrees with the two-layer interpretation of the shape of the force curves, and corresponds to the known structure of the corneocyte: i.e., an external lipid-protein envelope (the softer, outer layer) surrounding a stiffer, internal matrix of keratin filament bundles. The value of B100 MPa calculated for small indentation depths is similar to the surface elastic modulus of corneocytes determined by using indentation with standard AFM probes (Gaikwad et al, 2010). A significant scatter of results for depths 4100 nm, which can even be seen in data from the same volunteer, might possibly be attributed to local structural variations within corneocytes (perhaps due, as suggested above, to the presence of filaggrin at different stages in its degradation).…”

Section: Resultssupporting

confidence: 79%

Mechanical Tomography of Human Corneocytes with a Nanoneedle

Beard

Guy

Gordeev

2013

Journal of Investigative Dermatology

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Atomic force microscopy (AFM) can image biological samples and characterize their mechanical properties. However, the low aspect ratio of standard AFM probes typically limits these measurements to surface properties. Here, the intracellular mechanical behavior of human corneocytes is determined using "nanoneedle" AFM probes. The method evaluates the forces experienced by a nanoneedle as it is pushed into and then retracted from the cell. Indentation loops yield the stiffness profile and information on the elastic and nonelastic mechanical properties at a specific depth below the surface of the corneocytes. A clear difference between the softer ∼50-nm-thick external layer and the more rigid internal structure of corneocytes is apparent, which is consistent with the current understanding of the structure of these cells. There are also significant variations in the mechanical properties of corneocytes from different volunteers. The small diameter of the nanoneedle allows this "mechanical tomography" to be performed with high spatial resolution, potentially offering an opportunity to detect biomechanical changes in corneocytes because of, e.g., environmental factors, aging, or dermatological pathologies.

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Section: Resultssupporting

confidence: 79%

Mechanical Tomography of Human Corneocytes with a Nanoneedle

Beard

Guy

Gordeev

2013

Journal of Investigative Dermatology

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“…From the applied point of view, one can speculate that various skin diseases and abnormalities might be identified based on such images. These maps may also be interesting in cosmetics to characterize skin mechanical properties 53 . It might practically be interesting because of simplicity of collecting corneocytes.…”

Section: Resultsmentioning

confidence: 99%

High-resolution high-speed dynamic mechanical spectroscopy of cells and other soft materials with the help of atomic force microscopy

Dokukin

Sokolov

2015

Sci Rep

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Dynamic mechanical spectroscopy (DMS), which allows measuring frequency-dependent viscoelastic properties, is important to study soft materials, tissues, biomaterials, polymers. However, the existing DMS techniques (nanoindentation) have limited resolution when used on soft materials, preventing them from being used to study mechanics at the nanoscale. The nanoindenters are not capable of measuring cells, nanointerfaces of composite materials. Here we present a highly accurate DMS modality, which is a combination of three different methods: quantitative nanoindentation (nanoDMA), gentle force and fast response of atomic force microscopy (AFM), and Fourier transform (FT) spectroscopy. This new spectroscopy (which we suggest to call FT-nanoDMA) is fast and sensitive enough to allow DMS imaging of nanointerfaces, single cells, while attaining about 100x improvements on polymers in both spatial (to 10–70 nm) and temporal resolution (to 0.7s/pixel) compared to the current art. Multiple frequencies are measured simultaneously. The use of 10 frequencies are demonstrated here (up to 300 Hz which is a rather relevant range for biological materials and polymers, in both ambient conditions and liquid). The method is quantitatively verified on known polymers and demonstrated on cells and polymers blends. Analysis shows that FT-nanoDMA is highly quantitative. The FT-nanoDMA spectroscopy can easily be implemented in the existing AFMs.

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“…With the tactile working principle of AFM, mechanical properties like rigidity (Young's modulus) became accessible on subcellular level and have been reported for corneocytes as well . While dry corneocytes conceivably are more rigid than living keratinocytes (water makes soft), it is not predictable, how the contributions of cytoskeletal fibres or proteins or lipid mixture alter their rigidity in diseased states.…”

Section: Ex Vivo Methods For Barrier Assessmentmentioning

confidence: 99%

Assessing the skin barrier via corneocyte morphometry

Riethmüller

2018

Experimental Dermatology

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The skin barrier is an inevitable physiological function. Virtually all skin diseases exhibit an altered barrier. Because of its diversity, this vital function cannot be assessed adequately by a single method. Preference in both pharmaceutical and cosmetic testing is given to noninvasive assays, mostly macroscopic methods like optical or electrical or mechanical measurements. The present review focuses on advances in ultrastructural assays based on corneocytes obtained via tape stripping-highlighting candidates for automated processing. Among these are electron microscopic (EM) and atomic force microscopic (AFM) analyses, which are discussed with respect to clinical signs and skin hydration, as assessed by Raman spectroscopy or by concentration of natural moisturizing factor.

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Atomic force microscopy characterization of corneocytes: effect of moisturizer on their topology, rigidity, and friction

Abstract: AFM can be used as a very sensitive tool for early detection of changes in corneocytes.

Cited by 11 publications

References 23 publications

Mechanical Tomography of Human Corneocytes with a Nanoneedle

Mechanical Tomography of Human Corneocytes with a Nanoneedle

High-resolution high-speed dynamic mechanical spectroscopy of cells and other soft materials with the help of atomic force microscopy

Assessing the skin barrier via corneocyte morphometry

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