scholarly journals Mapping the mechanical microenvironment in the ovary

2021 ◽  
Author(s):  
Thomas I. R. Hopkins ◽  
Victoria L. Bemmer ◽  
Stephen Franks ◽  
Carina Dunlop ◽  
Kate Hardy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ex Vivo ◽  
Follicle Development ◽  
Human Ovary ◽  
Follicle Growth ◽  
Common Cause ◽  
Colloidal Probe ◽  
Afm Indentation ◽  
Atomic Force ◽  
Mechanical Microenvironment

AbstractFollicle development in the human ovary must be tightly regulated to ensure cyclical release of oocytes (ovulation), and disruption of this process is a common cause of infertility. Recent ex vivo studies suggest that follicle growth may be mechanically regulated, however the actual mechanical properties of the follicle microenvironment have remained unknown. Here we map and quantify the mechanical microenvironment in mouse ovaries using colloidal probe atomic force microscope (AFM) indentation, finding an overall mean Young’s Modulus 3.3 ± 2.5 kPa. Spatially, stiffness is low at the ovarian edge and centre, which are dominated by extra-follicular ECM, and highest in an intermediate zone dominated by large follicles. This suggests that large follicles should be considered as mechanically dominant structures in the ovary, in contrast to previous expectations. Our results provide a new, physiologically accurate framework for investigating how mechanics impacts follicle development and will underpin future tissue engineering of the ovary.

Measuring elasticity of wet cellulose beads with an AFM colloidal probe using a linearized DMT model

2017 ◽  
Vol 9 (27) ◽  
pp. 4019-4022 ◽  
Author(s):  
J. Hellwig ◽  
R.-M. P. Karlsson ◽  
L. Wågberg ◽  
T. Pettersson
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscope ◽  
Colloidal Probe ◽  
Atomic Force

The mechanical properties of wet cellulose are investigated using an atomic force microscope AFM and calculated using a linearized DMT model.

scholarly journals Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM

2012 ◽  
Vol 3 ◽  
pp. 778-788 ◽  
Author(s):  
Cagri Üzüm ◽  
Johannes Hellwig ◽  
Narayanan Madaboosi ◽  
Dmitry Volodkin ◽  
Regine von Klitzing
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Lateral Position ◽  
Growth Behaviour ◽  
Colloidal Probe ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Relaxation Measurements ◽  
Polymer Deposition

Scanning- and colloidal-probe atomic force microscopy were used to study the mechanical properties of poly(L-lysine)/hyaluronan (PLL/HA) n films as a function of indentation velocity and the number of polymer deposition steps n. The film thickness was determined by two independent AFM-based methods: scratch-and-scan and newly developed full-indentation. The advantages and disadvantages of both methods are highlighted, and error minimization techniques in elasticity measurements are addressed. It was found that the film thickness increases linearly with the bilayer number n, ranging between 400 and 7500 nm for n = 12 and 96, respectively. The apparent Young’s modulus E ranges between 15 and 40 kPa and does not depend on the indenter size or the film bilayer number n. Stress relaxation measurements show that PLL/HA films have a viscoelastic behaviour, regardless of their thickness. If indentation is performed several times at the same lateral position on the film, a viscous/plastic deformation takes place.

scholarly journals Melanoma Detection By AFM Indentation of Histological Specimens

2021 ◽  
Author(s):  
ByoungJun Jeon ◽  
Hyo Gi Jung ◽  
Sang Won Lee ◽  
Gyudo Lee ◽  
Jung Hee Shim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Histopathological Analysis ◽  
Anatomical Site ◽  
Cancer Stage ◽  
Gaussian Distributions ◽  
Force Microscopy ◽  
Benign Nevus ◽  
Melanoma Detection ◽  
Afm Indentation ◽  
Atomic Force

Abstract Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elasticity of melanoma displayed multimodal Gaussian distributions, exhibiting the heterogeneous mechanical properties, in contrast with the unimodal distributions of elasticity in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.

scholarly journals Melanoma Detection by AFM Indentation of Histological Specimens

2021 ◽  
Author(s):  
ByoungJun Jeon ◽  
Hyo Gi Jung ◽  
Sang Won Lee ◽  
Gyudo Lee ◽  
Jung Hee Shim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Histopathological Analysis ◽  
Anatomical Site ◽  
Cancer Stage ◽  
Gaussian Distributions ◽  
Force Microscopy ◽  
Benign Nevus ◽  
Melanoma Detection ◽  
Afm Indentation ◽  
Atomic Force

Abstract Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elasticity of melanoma displayed multimodal Gaussian distributions, exhibiting the heterogeneous mechanical properties, in contrast with the unimodal distributions of elasticity in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.

Investigating hollow corundum microspheres exfoliation of the elastomeric matrix

2019 ◽  
pp. 135-142
Author(s):  
N. V. Shadrinov ◽  
U. V. Evseeva
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscope ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
Elastomeric Matrix ◽  
Atomic Force

The results of study of the influence of hollow corundum microspheres HCM-S (5–100 µm) and HCM-L (70–180 µm) on the properties of nitrile butadiene rubber BNKS-18 are presented. The dependence of elastomer resistance to abrasion impact and physic and mechanical properties on the dispersion and concentration of hollow corundum microspheres is shown. The process of hollow corundum microspheres exfoliation of the elastomeric matrix, which largely determines the change of physic and mechanical properties, has been studied by specially developed stretching device compatible with an atomic force microscope. The paper describes microspheres exfoliation which is conventionally divided into 3 stages.

Mechanical Properties of Membrane Surface of Cultured Astrocyte Revealed by Atomic Force Microscopy

2000 ◽  
Vol 39 (Part 1, No. 6B) ◽  
pp. 3711-3716 ◽  
Author(s):  
Hatsuki Shiga ◽  
Yukako Yamane ◽  
Etsuro Ito ◽  
Kazuhiro Abe ◽  
Kazushige Kawabata ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Membrane Surface ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Nanocomposite Coating ◽  
Superhydrophobic Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Scanning Electron

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.

scholarly journals The Infuence of Salicin on Rheological and Film-Forming Properties of Collagen

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1661
Author(s):  
Katarzyna Adamiak ◽  
Katarzyna Lewandowska ◽  
Alina Sionkowska
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Infrared Spectroscopy ◽  
Rheological Properties ◽  
Silver Carp ◽  
Shear Tests ◽  
Force Microscopy ◽  
Atomic Force ◽  
Film Forming ◽  
Potential Applications

Collagen films are widely used as adhesives in medicine and cosmetology. However, its properties require modification. In this work, the influence of salicin on the properties of collagen solution and films was studied. Collagen was extracted from silver carp skin. The rheological properties of collagen solutions with and without salicin were characterized by steady shear tests. Thin collagen films were prepared by solvent evaporation. The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM). Mechanical properties were measured as well. It was found that the addition of salicin modified the roughness of collagen films and their mechanical and rheological properties. The above-mentioned parameters are very important in potential applications of collagen films containing salicin.

scholarly journals Granulosal and thecal expression of bone morphogenetic protein- and activin-binding protein mRNA transcripts during bovine follicle development and factors modulating their expression in vitro

Reproduction ◽  
2011 ◽  
Vol 142 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Claire Glister ◽  
Leanne Satchell ◽  
Phil G Knight
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Mrna Level ◽  
Transcript Abundance ◽  
Transforming Growth Factor Β ◽  
Follicle Development ◽  
Mrna Levels ◽  
Theca Interna

Evidence supports local roles for transforming growth factor β superfamily members including activins and bone morphogenetic proteins (BMP) in follicle development. Access of these ligands to signalling receptors is likely modulated by extracellular binding proteins (BP). In this study, we comparedex vivoexpression of four BPs (chordin, gremlin, noggin and follistatin) in granulosal (GC) and theca interna (TC) compartments of developing bovine antral follicles (1–18 mm). Effects of FSH and IGF on BMP and BP expression by cultured GC, and effects of LH and BMPs on BP expression by cultured TC were also examined. Follicular expression of all four BP transcripts was higher in GC than TC compartments (P<0.001) a finding confirmed by immunohistochemistry. Follicle category affected (P<0.01) gremlin and follistatin mRNA abundance, with a significant cell-type×follicle category interaction for chordin, follistatin and noggin. Noggin transcript abundance was lower (P<0.05) in GC of large ‘E-active’ than ‘E-inactive’ follicles while follistatin mRNA level was higher (P<0.01). FSH enhanced CYP19, FSHR, INHBA and follistatin by GC without affecting BMP or BMP–BP expression. IGF increased CYP19 and follistatin, reduced BMP4, noggin and gremlin but did not affect chordin orFSHRmRNA levels. LH increased TC androgen secretion but had no effect on BMP or BP expression. BMPs uniformly suppressed TC androgen production whilst increasing chordin, noggin and gremlin mRNA levels up to 20-fold (P<0.01). These findings support the hypothesis that extracellular BP, mostly from GC, contribute to the regulation of intrafollicular BMP/activin signalling. Enhancement of thecal BP expression by BMP implies an autoregulatory feedback role to prevent excessive signalling.

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