scholarly journals Nanostructural and mechanical changes in the sclera following proteoglycan depletion

2018 ◽  
Vol 2 (2) ◽  
pp. 14-17
Author(s):  
Zhuola Zhuola ◽  
Steve Barrett ◽  
Yalda Ashraf Kharaz ◽  
Riaz Akhtar
Keyword(s):  
Mechanical Properties ◽  
Collagen Fibril ◽  
Enzymatic Degradation ◽  
Ocular Tissues ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Fibril Morphology

The mechanical properties of ocular tissues, such as the sclera, have a major impact on healthy eye function, and are governed by the properties and composition of the microstructural components. For example, biomechanical degradation associated with myopia occurs alongside a reduction of proteoglycans (PGs). In this study, the role of PG degradation in the nanomechanical properties of the porcine sclera is explored. In-vitro enzymatic degradation of PGs was conducted with α-amylase and chondroitinase ABC enzymes. Collagen fibril morphology and nanomechanical stiffness were measured with atomic force microscopy (AFM). The elastic modulus of the tissue was reduced in all enzyme-treated samples relative to controls. In addition, collagen fibril organization was disrupted by PG depletion. Our data demonstrate that PGs play an important role in determining not only the mechanical properties at these length scales, but also collagen fibril arrangement.

scholarly journals Nanomechanical properties of enucleated cells: contribution of the nucleus to the passive cell mechanics

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Yuri M. Efremov ◽  
Svetlana L. Kotova ◽  
Anastasia A. Akovantseva ◽  
Peter S. Timashev
Keyword(s):  
Mechanical Properties ◽  
Cell Mechanics ◽  
Normal Cells ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Fibrosarcoma Cells ◽  
Actomyosin Cytoskeleton ◽  
Small Deformations

Abstract Background The nucleus, besides its functions in the gene maintenance and regulation, plays a significant role in the cell mechanosensitivity and mechanotransduction. It is the largest cellular organelle that is often considered as the stiffest cell part as well. Interestingly, the previous studies have revealed that the nucleus might be dispensable for some of the cell properties, like polarization and 1D and 2D migration. Here, we studied how the nanomechanical properties of cells, as measured using nanomechanical mapping by atomic force microscopy (AFM), were affected by the removal of the nucleus. Methods The mass enucleation procedure was employed to obtain cytoplasts (enucleated cells) and nucleoplasts (nuclei surrounded by plasma membrane) of two cell lines, REF52 fibroblasts and HT1080 fibrosarcoma cells. High-resolution viscoelastic mapping by AFM was performed to compare the mechanical properties of normal cells, cytoplasts, and nucleoplast. The absence or presence of the nucleus was confirmed with fluorescence microscopy, and the actin cytoskeleton structure was assessed with confocal microscopy. Results Surprisingly, we did not find the softening of cytoplasts relative to normal cells, and even some degree of stiffening was discovered. Nucleoplasts, as well as the nuclei isolated from cells using a detergent, were substantially softer than both the cytoplasts and normal cells. Conclusions The cell can maintain its mechanical properties without the nucleus. Together, the obtained data indicate the dominating role of the actomyosin cytoskeleton over the nucleus in the cell mechanics at small deformations inflicted by AFM.

scholarly journals Nanomechanical Characterization of Amyloid Fibrils Using Single-Molecule Experiments and Computational Simulations

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Bumjoon Choi ◽  
Taehee Kim ◽  
Sang Woo Lee ◽  
Kilho Eom
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Single Molecule ◽  
Amyloid Fibrils ◽  
Theoretical Models ◽  
Beam Model ◽  
Computational Simulations ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force

Amyloid fibrils have recently received much attention due to not only their important role in disease pathogenesis but also their excellent mechanical properties, which are comparable to those of mechanically strong protein materials such as spider silk. This indicates the necessity of understanding fundamental principles providing insight into how amyloid fibrils exhibit the excellent mechanical properties, which may allow for developing biomimetic materials whose material (e.g., mechanical) properties can be controlled. Here, we describe recent efforts to characterize the nanomechanical properties of amyloid fibrils using computational simulations (e.g., atomistic simulations) and single-molecule experiments (e.g., atomic force microscopy experiments). This paper summarizes theoretical models, which are useful in analyzing the mechanical properties of amyloid fibrils based on simulations and experiments, such as continuum elastic (beam) model, elastic network model, and polymer statistical model. In this paper, we suggest how the nanomechanical properties of amyloid fibrils can be characterized and determined using computational simulations and/or atomic force microscopy experiments coupled with the theoretical models.

scholarly journals The Inhibitory Effect of Resveratrol on Elastin Amyloidogenesis

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Antonietta Pepe ◽  
Florian Delaunay ◽  
Angelo Bracalello ◽  
Brigida Bochicchio
Keyword(s):  
Molecular Structure ◽  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Inhibitory Effect ◽  
Degenerative Diseases ◽  
Force Microscopy ◽  
Atomic Force ◽  
Circular Dichroïsm

The role of polyphenols in the prevention of degenerative diseases is emerging in the last years. In this report, we will investigate in vitro the inhibitory effect of resveratrol on elastin amyloidogenesis. The effect of resveratrol on molecular structure was investigated by circular dichroism spectroscopy, while the inhibitory effect on self-assembly was evaluated by turbidimetry as a function of temperature and by atomic force microscopy.

scholarly journals In vitro Performance of Nano-heterogeneous Dentin Adhesive

2008 ◽  
Vol 87 (9) ◽  
pp. 829-833 ◽  
Author(s):  
Q. Ye ◽  
J.G. Park ◽  
E. Topp ◽  
Y. Wang ◽  
A. Misra ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Image ◽  
Force Microscopy ◽  
Dental Tissues ◽  
Atomic Force ◽  
Dentin Adhesives ◽  
Mechanical Durability ◽  
Nanophase Separation ◽  
High Degree

Water is ubiquitous in the mouths of healthy individuals and routinely interferes with efforts to bond restorations to dental tissues. Our previous studies using tapping-mode atomic force microscopy (TMAFM) have shown that nanophase separation is a general feature of cross-linked polymethacrylates photocured in the presence of water. To explore the relationship between nanophase separation in dentin adhesives and their long-term mechanical properties, we evaluated model adhesives after 3 months of aqueous storage. The degree of contrast in the TMAFM phase image depended on the formulations used, ranging from ‘not observable’ to ‘very strong’. Correspondingly, the mechanical properties of these model adhesives varied from ‘minimal change’ to ‘significant depreciation’. The results support the hypothesis that a high degree of heterogeneity at the nano-scale is associated with poor mechanical durability in these model adhesives.

scholarly journals Ultrastructural and nanomechanical changes of the cornea following enzymatic degradation

2018 ◽  
Vol 2 (2) ◽  
pp. 24-29
Author(s):  
Ahmed Kazaili ◽  
Riaz Akhtar
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Enzymatic Degradation ◽  
Enzymatic Treatment ◽  
Force Microscopy ◽  
Collagen Organization ◽  
Atomic Force ◽  
Ocular Disorders ◽  
Porcine Cornea

Understanding of the ultrastructure and nanomechanical behavior of the cornea is important for a number of ocular disorders. In this study, atomic force microscopy (AFM) was used to determine nanoscale changes in the porcine cornea following enzymatic degradation. Diff erent concentrations of amylase were used to degrade the cornea. A reduction in elastic modulus at the nanoscale, along with disrupted collagen morphology, was observed following enzymatic treatment. This study highlights the interplay between mechanical properties and collagen organization in the healthy cornea.

scholarly journals Analysis of nanomechanical properties of Borrelia burgdorferi spirochetes under the influence of lytic factors in an in vitro model using atomic force microscopy

2015 ◽  
Vol 69 ◽  
pp. 1222-1227 ◽  
Author(s):  
Małgorzata Tokarska-Rodak ◽  
Maria Kozioł-Montewka ◽  
Krzysztof Skrzypiec ◽  
Tomasz Chmielewski ◽  
Ewaryst Mendyk ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Borrelia Burgdorferi ◽  
In Vitro Model ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Vitro Model

Nanomechanical Properties of Tooth and Bone Revealed by Nanoindentation and AFM

2007 ◽  
Vol 353-358 ◽  
pp. 2263-2266 ◽  
Author(s):  
Fu Zhai Cui ◽  
Zhen Jiang Chen ◽  
Jun Ge
Keyword(s):  
Mechanical Properties ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Mechanical Measurements ◽  
Hard Tissues ◽  
Instrument Technology ◽  
Properties Of Materials ◽  
Skeletal Bone ◽  
Different Parts

In this paper, an overview on nanoindentation and its combination with AFM is presented with regard to current instrument technology and applications on dental and bony tissues. Nanoindentation has been a widely used technique to determine the mechanical properties such as nanohardness and Young’s modulus for nanostructured materials. Especially, atomic force microscopy (AFM) combined with nanoindentation, with the pit positions controlled accurately, become a powerful technique used to measure mechanical properties of materials on the nanoscale, and has been applied to the study of biological hard tissues, such as bone and tooth. Examples will be shown that significantly different nanohardness and modulus in the isolated domains within single enamel, the prisms, interprisms, the surrounding sheaths and the different parts of skeletal bone, could been distinguished, while such information was unable to be obtained by traditional methods of mechanical measurements.

scholarly journals Role of Polysaccharides on Mechanical and Adhesion Properties of Flax Fibres in Flax/PLA Biocomposite

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Gijo Raj ◽  
Eric Balnois ◽  
Christophe Baley ◽  
Yves Grohens
Keyword(s):  
Mechanical Properties ◽  
Morphological Changes ◽  
Cellulose Microfibrils ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Flax Fibres ◽  
Atomic Force ◽  
Multilength Scale ◽  
Fibre Morphology

The effect of alkali and enzymatic treatments on flax fibre morphology, mechanical, and adhesion properties was investigated. The multilength scale analysis allows for the correlation of the fibre's morphological changes induced by the treatments with mechanical properties to better explain the adherence properties between flax and PLA. The atomic force microscopy (AFM) images revealed the removal of primary layers, upon treatments, down to cellulose microfibrils present in the secondary layers. The variation in mechanical properties was found to be dependent, apart from the crystalline content, on interaction between cellulose microfibrils and encrusting polysaccharides, pectins and hemicelluloses, in the secondary layers. Finally, microbond tests between the modified fibres and PLA emphasize the important role of the outer fibre's surface on the overall composite properties. It was observed here that gentle treatments of the fibres, down to the oriented microfibrils, are favourable to a better adherence with a PLA drop. This paper highlights the important role of amorphous polymers, hemicellulose and pectin, in the optimisation of the adhesion and mechanical properties of flax fibres in the biocomposite.

scholarly journals Role of AL, FE, CU in the Alterations of Mechanical Properties of Cortical Neurons Probed by Atomic Force Microscopy

2016 ◽  
Vol 110 (3) ◽  
pp. 148a
Author(s):  
Maria Carmela Lauriola ◽  
Massimiliano Papi ◽  
Giuseppe Maulucci ◽  
Gabriele Ciasca ◽  
Valentina Palmieri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Cortical Neurons ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Atomic force microscopy reveals the mechanical properties of breast cancer bone metastases

2021 ◽  
Author(s):  
Xinyue Chen ◽  
Russell Hughes ◽  
Nic Mullin ◽  
Rhoda J Hawkins ◽  
Ingunn Holen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Metastatic Cancer ◽  
Metastatic Breast ◽  
Metastatic Tumour ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cancer Metastases

Mechanically dependent processes are essential in cancer metastases. However, reliable mechanical characterisation of metastatic cancer remains challenging whilst maintaining the tissue complexity and an intact sample. Using atomic force microscopy, we quantified the micro-mechanical properties of relatively intact metastatic breast tumours and their surrounding bone microenvironment isolated from mice, and compared with other breast cancer models both ex vivo and in vitro. A unique mechanical distribution of extremely low elastic modulus and viscosity was identified on metastatic tumours, which were significantly more compliant than both 2D in vitro cultured cancer cells and subcutaneous tumour explants. The presence of mechanically distinct metastatic tumour did not result in alterations of the mechanical properties of the surrounding microenvironment at meso-scale distances (> 200 μm). These findings demonstrate the utility of atomic force microscopy in studies of complex tissues and provide new insights into the mechanical properties of cancer metastases in bone.

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