Apparent elastic modulus and hysteresis of skeletal muscle cells throughout differentiation

2002 ◽  
Vol 283 (4) ◽  
pp. C1219-C1227 ◽  
Author(s):  
Amy M. Collinsworth ◽  
Sarah Zhang ◽  
William E. Kraus ◽  
George A. Truskey
Keyword(s):  
Mechanical Properties ◽  
Skeletal Muscle ◽  
Elastic Modulus ◽  
Viscoelastic Behavior ◽  
Muscle Cells ◽  
Cytochalasin D ◽  
Skeletal Muscle Cells ◽  
Force Microscopy ◽  
Relative Contribution ◽  
Atomic Force

The effect of differentiation on the transverse mechanical properties of mammalian myocytes was determined by using atomic force microscopy. The apparent elastic modulus increased from 11.5 ± 1.3 kPa for undifferentiated myoblasts to 45.3 ± 4.0 kPa after 8 days of differentiation ( P< 0.05). The relative contribution of viscosity, as determined from the normalized hysteresis area, ranged from 0.13 ± 0.02 to 0.21 ± 0.03 and did not change throughout differentiation. Myosin expression correlated with the apparent elastic modulus, but neither myosin nor β-tubulin were associated with hysteresis. Microtubules did not affect mechanical properties because treatment with colchicine did not alter the apparent elastic modulus or hysteresis. Treatment with cytochalasin D or 2,3-butanedione 2-monoxime led to a significant reduction in the apparent elastic modulus but no change in hysteresis. In summary, skeletal muscle cells exhibited viscoelastic behavior that changed during differentiation, yielding an increase in the transverse elastic modulus. Major contributors to changes in the transverse elastic modulus during differentiation were actin and myosin.

Stretch-induced nitric oxide modulates mechanical properties of skeletal muscle cells

2004 ◽  
Vol 287 (2) ◽  
pp. C292-C299 ◽  
Author(s):  
Jingying Sarah Zhang ◽  
William E. Kraus ◽  
George A. Truskey
Keyword(s):  
Nitric Oxide ◽  
Mechanical Properties ◽  
Skeletal Muscle ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Calpain Inhibitor ◽  
No Donor ◽  
Static Stretch ◽  
Force Microscopy ◽  
Protein Levels

In this study, we examined the hypothesis that stretch-induced (nitric oxide) NO modulates the mechanical properties of skeletal muscles by increasing accumulation of protein levels of talin and vinculin and by inhibiting calpain-induced proteolysis, thereby stabilizing the focal contacts and the cytoskeleton. Differentiating C2C12 myotubes were subjected to a single 10% step stretch for 0–4 days. The apparent elastic modulus of the cells, Eapp, was subsequently determined by atomic force microscopy. Static stretch led to significant increases ( P < 0.01) in Eapp beginning at 2 days. These increases were correlated with increases in NO activity and neuronal NO synthase (nNOS) protein expression. Expression of talin was upregulated throughout, whereas expression of vinculin was significantly increased only on days 3 and 4. Addition of the NO donor l-arginine onto stretched cells further enhanced Eapp, NOS activity, and nNOS expression, whereas the presence of the NO inhibitor Nω-nitro-l-arginine methyl ester (l-NAME) reversed the effects of mechanical stimulation and of l-arginine. Overall, viscous dissipation, as determined by the value of hysteresis, was not significantly altered. For assessment of the role of vinculin and talin stability, cells treated with l-NAME showed a significant decrease in Eapp, whereas addition of a calpain inhibitor abolished the effect. Thus our results show that NO inhibition of calpain-initiated cleavage of cytoskeleton proteins was correlated with the changes in Eapp. Together, our data suggest that NO modulates the mechanical behavior of skeletal muscle cells through the combined action of increased talin and vinculin levels and a decrease in calpain-mediated talin proteolysis.

Nanoscale Mechanical Properties of Polymer Composites: Changes in Elastic Modulus and Measurement of Ion Penetration Depth Due to α-radiation

2000 ◽  
Vol 15 (4) ◽  
pp. 838-841
Author(s):  
Allen T. Chien ◽  
Tom Felter ◽  
James D. LeMay ◽  
Mehdi Balooch
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Penetration Depth ◽  
Depth Profiling ◽  
Force Microscopy ◽  
Microscopy Technique ◽  
Atomic Force ◽  
Sample Edge ◽  
Composite Samples ◽  
Ion Penetration

The local mechanical properties of silica-reinforced silicone composites were investigated using a modified atomic force microscopy technique. Elastic modulus measurements (1.5 ± 0.1 MPa) are consistent with bulk measurements (1.9 MPa), and changes in the modulus at the surface of the composite samples (E = 1.5 to 3.5 MPa) were observed as a result of α-irradiation (dose = 1.7 × 1010 to 2.0 × 1012 α/cm2). The sensitivity of the technique was demonstrated by a detectable change in modulus at even the small dose of 1.7 × 1010 α/cm2. The penetration depth of the α-particles into the material, estimated to be 22 ± 2 μm from the sample edge, was determined by cross-section depth profiling; and modeling of the ion penetration depth using transport of ions in matter codes (24.4 ± 0.4 μm) closely matched experimental observations.

Atomic force microscopy-based nanomechanical characterization of kenaf fiber

2019 ◽  
Vol 54 (15) ◽  
pp. 2065-2071 ◽  
Author(s):  
M Subbir Parvej ◽  
Xinnan Wang ◽  
Joseph Fehrenbach ◽  
Chad A Ulven
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Adhesion Force ◽  
Fiber Surface ◽  
Gauge Length ◽  
Hibiscus Cannabinus ◽  
Kenaf Fiber ◽  
Force Microscopy ◽  
Atomic Force

Kenaf ( Hibiscus cannabinus L.) fiber is being extensively used as a reinforcement material in composites due to its excellent mechanical properties. To use this fiber more efficiently, it is necessary to understand its mechanical properties at micro/nano meter scale. Despite the evidence of some past studies to determine the elastic modulus of kenaf fiber, most of them were performed on fiber bundles. Bundle-based method to find the elastic moduli has some obvious issues of foreign materials being present, incorrect gauge length, and sample diameter due to void spaces. These issues pose as obvious hurdles to determine the elastic modulus accurately. In this study, individual kenaf micro fiber was used to find elastic modulus in the radial direction. The radial elastic modulus of the fiber was characterized by atomic force microscopy-based nanoindentation. To determine the radial elastic modulus from the force versus sample deformation data, the extended Johnson–Kendall–Roberts model was used which considered adhesion force from the fiber surface. The radial elastic modulus of the kenaf fiber was found to be 2.3 GPa.

scholarly journals Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J. K. Wenderott ◽  
Carmen G. Flesher ◽  
Nicki A. Baker ◽  
Christopher K. Neeley ◽  
Oliver A. Varban ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metabolic Disease ◽  
Atomic Force Microscopy ◽  
Adipose Tissue ◽  
Elastic Modulus ◽  
Tissue Mechanics ◽  
Health Concern ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

AbstractObesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.

Mechanical properties of the interaction between fibronectin and α5β1-integrin on vascular smooth muscle cells studied using atomic force microscopy

2005 ◽  
Vol 289 (6) ◽  
pp. H2526-H2535 ◽  
Author(s):  
Zhe Sun ◽  
Luis A. Martinez-Lemus ◽  
Andreea Trache ◽  
Jerome P. Trzeciakowski ◽  
George E. Davis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Focal Contact ◽  
Force Microscopy ◽  
Atomic Force

The mechanical properties of integrin-extracellular matrix (ECM) interactions are important for the mechanotransduction of vascular smooth muscle cells (VSMC), a process that is associated with focal adhesions, and can be of particular significance in cardiovascular disease. In this study, we characterized the unbinding force and binding activity of the initial fibronectin (FN)-α5β1 interaction on the surface of VSMC using atomic force microscopy (AFM). It is postulated that these initial binding events are important to the subsequent focal adhesion assembly. FN-VSMC adhesions were selectively blocked by antibodies against α5- and β1-integrins as well as RGD-containing peptides but not by antibodies against α4- and β3-integrins, indicating that FN primarily bound to α5β1. A characteristic unbinding force of 39 ± 8 pN was observed and interpreted to represent the FN-α5β1 single-bond strength. The ability of FN to adhere to VSMC (binding probability) was significantly reduced by integrin antagonists, serum starvation, and platelet-derived growth factor (PDGF)-BB, whereas lysophosphatidic acid (LPA) increased FN binding. However, no significant change in the resolved unbinding force was observed. After engagement, the force required to dislodge the FN-coated bead from VSMC increased with increasing of contact time, suggesting a time-dependent increase in number of adhesions and/or altered binding affinity. LPA enhanced this process, whereas PDGF reduced it, suggesting that these factors also affect the multimolecular process of focal contact assembly. Thus AFM is a powerful tool for the characterization of the mechanical properties of integrin-ECM interactions and their regulation. Our results indicate that the functional activity of α5β1 and focal contact assembly can be rapidly regulated.

Mapping of Nanoscale Mechanical Properties of Polymers in Quasi-static and Oscillatory Atomic Force Microscopy Modes

MRS Advances ◽  
2016 ◽  
Vol 1 (40) ◽  
pp. 2763-2768 ◽  
Author(s):  
Sergei Magonov ◽  
Marko Surtchev ◽  
John Alexander ◽  
Ivan Malovichko ◽  
Sergey Belikov
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Polymer Materials ◽  
Work Of Adhesion ◽  
Force Microscopy ◽  
Atomic Force ◽  
Time Dependencies ◽  
Force Curves ◽  
20 Nm

ABSTRACTRecent advances in studies of local mechanical properties of polymers with different atomic force microscopy techniques (contact, Hybrid and amplitude modulation modes) are described in interplay between experiment and theory. Analysis of force curves and time dependencies of probe response to sample compliance, which were recorded on a number of polymer materials at various temperatures, leads to quantitative mapping of specific mechanical properties (elastic modulus, work of adhesion, etc). High spatial resolution of elastic modulus mapping (10-20 nm) is illustrated in measurements of lamellar structures of several polymers. Challenges of examination of viscoelastic properties are pointed out and a possible solution is presented.

scholarly journals Quantitative Nanomechanical Mapping of Polyolefin Elastomer at Nanoscale with Atomic Force Microscopy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shuting Zhang ◽  
Yihui Weng ◽  
Chunhua Ma
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Response ◽  
Adhesion Force ◽  
Time Dependent ◽  
Surface Adhesion ◽  
Force Microscopy ◽  
Mechanics Model ◽  
Atomic Force ◽  
Force Volume

AbstractElastomeric nanostructures are normally expected to fulfill an explicit mechanical role and therefore their mechanical properties are pivotal to affect material performance. Their versatile applications demand a thorough understanding of the mechanical properties. In particular, the time dependent mechanical response of low-density polyolefin (LDPE) has not been fully elucidated. Here, utilizing state-of-the-art PeakForce quantitative nanomechanical mapping jointly with force volume and fast force volume, the elastic moduli of LDPE samples were assessed in a time-dependent fashion. Specifically, the acquisition frequency was discretely changed four orders of magnitude from 0.1 up to 2 k Hz. Force data were fitted with a linearized DMT contact mechanics model considering surface adhesion force. Increased Young’s modulus was discovered with increasing acquisition frequency. It was measured 11.7 ± 5.2 MPa at 0.1 Hz and increased to 89.6 ± 17.3 MPa at 2 kHz. Moreover, creep compliance experiment showed that instantaneous elastic modulus E1, delayed elastic modulus E2, viscosity η, retardation time τ were 22.3 ± 3.5 MPa, 43.3 ± 4.8 MPa, 38.7 ± 5.6 MPa s and 0.89 ± 0.22 s, respectively. The multiparametric, multifunctional local probing of mechanical measurement along with exceptional high spatial resolution imaging open new opportunities for quantitative nanomechanical mapping of soft polymers, and can potentially be extended to biological systems.

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.

In Situ Measurement of Elastic and Frictional Properties Using Atomic Force Microscopy

2021 ◽  
pp. 1-10
Author(s):  
Ngoc-Phat Huynh ◽  
Tuan-Em Le ◽  
Koo-Hyun Chung
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Force Microscopy ◽  
Frictional Properties ◽  
Atomic Force ◽  
Proposed Model ◽  
Significant Difference ◽  
Modulus Measurement

Atomic force microscopy (AFM) can determine mechanical properties, associated with surface topography and structure, of a material at the nanoscale. Force–indentation curves that depict the deformation of a target specimen as a function of an applied force are widely used to determine the elastic modulus of a material based on a contact model. However, a hysteresis may arise due to friction between the AFM tip and a specimen. Consequently, the normal force detected using a photodetector during extension and retraction could be underestimated and overestimated, respectively, and the extension/retraction data could result in a significant difference in the elastic modulus measurement result. In this study, elastic modulus and friction coefficient values were determined based on an in situ theoretical model that compensated for the effect of friction on force–indentation data. It validated the proposed model using three different polymer specimens and colloidal-tipped probes for the force–indentation curve and friction loop measurements. This research could contribute to the accurate measurement of mechanical properties using AFM by enhancing the interpretation of force–indentation curves with friction-induced hysteresis. Furthermore, the proposed approach may be useful for analyzing in situ relationships between mechanical and frictional properties from a fundamental tribological perspective.

Measurement of the Transverse Apparent Elastic Modulus in Mammalian Cardiac Myocytes

2003 ◽  
Author(s):  
Samuel C. Lieber ◽  
Nadine Aubry ◽  
Jayashree Pain ◽  
Gissela Diaz ◽  
Song-Jung Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Brown Norway ◽  
F1 Hybrid ◽  
Force Microscopy ◽  
Physiological Processes ◽  
Atomic Force ◽  
Afm Probe

Transverse mechanical properties of mammalian cardiac myocytes, was determined by using atomic force microscopy (AFM). The AFM can be used as a nano-indentation device allowing transverse stiffness measurements to be conducted on biological cells in a physiological environment. This enables real-time biomechanical and physiological processes to be monitored with nano-scale resolution. Cellular mechanical properties were determined by indenting the cell’s body, and analyzing the indentation data with classical infinitesimal strain theory (CIST). This calculation was accomplished by modeling the AFM probe as a blunted cone. The blunted cone geometry fits the AFM force indentation data well and was used to calculate the apparent elastic modulus of the cardiac myocyte body. The mechanical properties of male 344 x Brown Norway F1 hybrid (F344×BN) rat cells was measured and an apparent elastic modulus of 35.1 ± 0.7 kPa (n = 53) was calculated. Further studies are being conducted on myocytes isolated from aged hearts to determine whether age effects cardiac mechanical properties at the level of the single myocyte.

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