Microscopic Methods for Characterization of Selected Surface Properties of Biodegradable, Nanofibrous Tissue Engineering Scaffolds

2017 ◽  
Vol 890 ◽  
pp. 213-216 ◽  
Author(s):  
Adrian Chlanda ◽  
Ewa Kijeńska ◽  
Wojciech Święszkowski
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Force Spectroscopy ◽  
Operating Mode ◽  
Tissue Engineering Scaffolds ◽  
Force Microscopy ◽  
Atomic Force

Biodegradable polymeric fibers with nanoand submicron diameters, produced by electrospinning can be used as scaffolds in tissue engineering. It is necessary to characterize their mechanical properties especially at the nanoscale. The Force Spectroscopy is suitable atomic force microscopy mode, which allows to probe mechanical properties of the material, such as: reduced Young's modulus, deformation, adhesion, and dissipation. If combined with standard operating mode: contact or semicontact, it will also provide advanced topographical analysis. In this paper we are presenting results of Force Spectroscopy characterization of two kinds of electrospun fibers: polycaprolactone and polycaprolactone with hydroxyapatite addition. The average calculated from Johnson-Kendall-Roberts theory Young's modulus was 4 ± 1 MPa for pure polymer mesh and 20 ± 3 MPa for composite mesh.

scholarly journals Alteration of nanomechanical properties of pancreatic cancer cells through anticancer drug treatment revealed by atomic force microscopy

2021 ◽  
Vol 12 ◽  
pp. 1372-1379
Author(s):  
Xiaoteng Liang ◽  
Shuai Liu ◽  
Xiuchao Wang ◽  
Dan Xia ◽  
Qiang Li
Keyword(s):  
Mechanical Properties ◽  
Pancreatic Cancer ◽  
Atomic Force Microscopy ◽  
Cancer Cells ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Force Microscopy ◽  
Pancreatic Cancer Cells ◽  
Atomic Force ◽  
Aggressive Cancer

The mechanical properties of cells are key to the regulation of cell activity, and hence to the health level of organisms. Here, the morphology and mechanical properties of normal pancreatic cells (HDPE6-C7) and pancreatic cancer cells (AsPC-1, MIA PaCa-2, BxPC-3) were studied by atomic force microscopy. In addition, the mechanical properties of MIA PaCa-2 after treatment with different concentrations of doxorubicin hydrochloride (DOX) were also investigated. The results show the Young's modulus of normal cells is greater than that of three kinds of cancer cells. The Young's modulus of more aggressive cancer cell AsPC-1 is smaller than that of less aggressive cancer cell BxPC-3. In addition, the Young's modulus of MIA PaCa-2 rises with the increasing of DOX concentration. This study may provide a new strategy of detecting cancer, and evaluate the possible interaction of drugs on cells.

Mechanical Characterization of Hepatoma Cells Using Atomic Force Microscope

2011 ◽  
Vol 694 ◽  
pp. 869-873
Author(s):  
Jing He Wang ◽  
Miao Yu ◽  
Li Liu ◽  
Jie Zhao ◽  
Hong Xiang Wang
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Hepatoma Cell ◽  
Hepatoma Cells ◽  
Peripheral Region ◽  
Hertz Model ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Difference

In order to reveal variation of mechanical properties of hepatoma cells with nanometer resolution, atomic force microscopy (AFM)-based nanoindentation experiments are performed on hepatoma cell to derive Young’s modulus employing a corrected Hertz model. Under load conditions of nanoindentation force as 0.43809-0.73015nN and penetration rate as 0.4 Hz, the calculated value of Young’s modulus of hepatoma cells is 34.137±0.67kPa with a 95% confidence interval. The results demonstrate the Young’s modulus varies with the measurement position, and the center of cell possesses lower value than peripheral region. Variation of Young’s modulus is resulted from external reaction, which supports well the theory of cytoskeleton structure. Furthermore, the difference of Young’s modulus between normal cells and cancerous ones are also discussed, and it will provide possibility of a new route for early diagnosis of hepatoma.

scholarly journals Atomic Simulation of Nanoindentation on the Regular Wrinkled Graphene Sheet

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1127
Author(s):  
Ruonan Wang ◽  
Haosheng Pang ◽  
Minglin Li ◽  
Lianfeng Lai
Keyword(s):  
Mechanical Properties ◽  
Boundary Condition ◽  
Boundary Conditions ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Md Simulations ◽  
Force Microscopy ◽  
Atomic Simulation ◽  
Atomic Force ◽  
Surface Wrinkling

Surface landscapes have vague impact on the mechanical properties of graphene. In this paper, single-layered graphene sheets (SLGS) with regular wrinkles were first constructed by applying shear deformation using molecular dynamics (MD) simulations and then indented to extract their mechanical properties. The influence of the boundary condition of SLGS were considered. The wrinkle features and wrinkle formation processes of SLGS were found to be significantly related to the boundary conditions as well as the applied shear displacement and velocity. The wrinkling amplitude and degree of wrinkling increased with the increase in the applied shear displacements, and the trends of wrinkling wavelengths changed with the different boundary conditions. With the fixed boundary condition, the degree of graphene wrinkling was only affected when the velocity was greater than a certain value. The effect of wrinkles on the mechanical characterization of SLGS by atomic force microscopy (AFM) nanoindentation was finally investigated. The regular surface wrinkling of SLGS was found to weaken the Young’s modulus of graphene. The Young’s modulus of graphene deteriorates with the increase in the degree of regular wrinkling.

Microstructure and Mechanical Properties of TiN/NbN Multilayered Coating

2010 ◽  
Vol 434-435 ◽  
pp. 466-468
Author(s):  
Chien Cheng Liu ◽  
Kuang I Liu ◽  
Huai Wei Yan ◽  
Chia Li Ma ◽  
Jow Lay Huang
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Steel Ball ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pin On Disk ◽  
Heating Up ◽  
Steel Substrates ◽  
Stylus Profiler

In this study, multilayers of TiN/NbN were deposited by d.c. magnetron sputtering on die steel substrates. The structure, morphology and nano-hardness were assessed using X-ray diffraction, atomic force microscopy (AFM), stylus profiler (XP-2 stylus profiler) and nanoindentation, respectively. Wear tests were performed on pin-on-disk configuration and dry sliding conditions, at 5N load by using hardened steel ball. The result shows TiN with highly (111) preferred orientation. On mechanical properties, Young’s modulus and hardness values increase for layers number increase. At 64 layers films had the highest nano-hardness, Young’s modulus values. The TiN/NbN multilayer films presented changes in its morphology becoming more granulated and density after heating up to 500°C. A significant decrease in friction coefficient has been achieved for TiN/NbN multilayers against steel ball.

Characterization of Gold Nanowire Through Beam Deflection Using Atomic Force Microscopy

2011 ◽  
Author(s):  
Paul Phamduy ◽  
Adam McLaughlin ◽  
Fan Gao ◽  
Byungki Kim ◽  
Zhiyong Gu
Keyword(s):  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Beam Deflection ◽  
Gold Nanowire ◽  
Force Microscopy ◽  
Atomic Force ◽  
Order Of Magnitude ◽  
Deflection Test

The objective of this report is to calculate the Young’s modulus of gold cantilevers on the nanoscale using a force-deflection test performed on an Atomic Force Microscope (AFM). These results are then compared to the Young’s modulus of gold on the macroscale. As shown from the results, the beam deflection tests confirm that the elastic modulus values obtained by this method are on the same order of magnitude as its macroscale counterpart.

scholarly journals Finite Element Analysis of Porosity Effects on Mechanical Properties for Tissue Engineering Scaffold

2020 ◽  
Vol 11 (2) ◽  
pp. 8836-8843
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Pore Size ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Vital Role ◽  
Tissue Engineering Scaffolds ◽  
Element Analysis

Porosity plays a vital role in the development of tissue engineering scaffolds. It influences the biocompatibility performance of the scaffolds by increasing cell proliferation and allowing the transportation of the nutrients, oxygen, and metabolites in the blood rapidly to generate new tissue structure. However, a high amount of porosity can reduce the mechanical properties of the scaffold. Thus, this study aims to determine the geometry of the porous structure of a scaffold which exhibits good mechanical properties while maintaining its porosity at a percentage of more than 80%. Circle and square geometries were used since they are categorized as simple geometry. A unit cell of 12mm x 12mm x 12mm for square shape and pore area of 25π mm2 for circle shape was modeled and simulated by using Finite Element Analysis. The simulation consists of a compression test that determines which geometry exhibits better Young’s Modulus. Since the circle geometry has better Young’s Modulus, the pore size was furthered varied while maintaining the porosity of the scaffold to be above 80%. The same method of the simulation was done on the models. The result shows that the smallest pore size model has the highest Young’s Modulus, which still able to maintain the porosity at 80%.

Accurate determination of the mechanical properties of thin aluminum films deposited on sapphire flats using nanoindentations

1999 ◽  
Vol 14 (6) ◽  
pp. 2314-2327 ◽  
Author(s):  
Y. Y. Lim ◽  
M. M. Chaudhri ◽  
Y. Enomoto
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Accurate Determination ◽  
Direct Methods ◽  
Polycrystalline Aluminum ◽  
Aluminum Films ◽  
Force Microscopy ◽  
Contact Areas ◽  
Atomic Force

Nanoindentations using a Berkovich diamond indenter have been made on 1, 2, and 5 μm thick 99.99% purity polycrystalline aluminum films thermally evaporated in vacuum on to 2 mm thick R-cut polished sapphire flats. The projected contact areas of the residual indentations were estimated from the unloading load-displacement curves, and some of the indentations were imaged with an atomic force microscope (AFM). It was found that a large majority of indents showed material pileup, and the projected areas of these indents, as measured with the AFM, were up to 50% greater than those calculated from the unloading curves. This discrepancy between the calculated and directly measured indentation areas has a strong influence on the derived values of Young's modulus and hardness of the aluminum films. Using a new analytical model, Young's modulus of the aluminum films has been determined to be in the range of 50–70 GPa, independent of the relative indentation depth. The composite nanohardness of the 1 and 2 μm thick films was found to have a load-independent value of 1 GPa, whereas the composite nanohardness of the 5 μm film decreased from 1 to 0.7 Gpa with increasing indenter penetration. Finally, it has been suggested that in order to improve the accuracy with which the mechanical properties of thin films or bulk specimens can be determined by nanoindentation techniques, the projected contact areas should be measured by direct methods, such as atomic force microscopy.

scholarly journals Evaluation methods of mechanical properties for low-k dielectrics

2021 ◽  
Vol 9 (3) ◽  
pp. 40-48
Author(s):  
I. S. Ovchinnikov
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Dielectric Constant ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Low Dielectric Constant ◽  
Insulating Materials ◽  
Force Microscopy ◽  
Low Dielectric ◽  
Atomic Force

This review introduces the study of state-of-art methods for assessing the mechanical properties of insulating materials with low dielectric constant. The main features of measuring Young’s modulus of thin films insulating materials with low dielectric constant are determined by usage of Brillouin light scattering, surface acoustic wave spectroscopy, picosecond laser-acoustic method, ellipsometric porosimetry, nanoindentation and atomic force microscopy in various modes. The author estimated the optimum lateral and optimum depth resolution for each above method. The review analyzes the degree of sample preparation complexity for the measurements by these methods and describes what methods of measurement are destructive for the samples. Besides, the review makes a comparison for the results of evaluating Young’s modulus of insulating materials with low dielectric constant achieved by different methods. Comparative analysis of the methods for assessing mechanical properties lead us to the conclusion that the method of atomic force microscopy is superior to other methods described above, both in lateral (8 nm) and optimum depth (10 nm) resolution. It is shown that due to the small impact force of the atomic force microscope probe on the surface, the method does not have a destructive effect on the sample. In addition, there is no need to create special conditions for the experiment (e.g., the cleanliness level of the premises, the possibility of an experiment under environmental conditions, etc.). This makes the experiment relatively simple in terms of preparing the object of research. It has been also established that the method of atomic force microscopy in the mode of quantitative nanomechanical mapping allows forming a map of the distribution of the Young’s modulus of the insulating material as part of the metallization system of integrated circuits.

scholarly journals Mechanical Properties of Isolated Primary Cilia Measured by Micro-tensile Test and Atomic Force Microscopy

2021 ◽  
Vol 9 ◽  
Author(s):  
Tien-Dung Do ◽  
Jimuro Katsuyoshi ◽  
Haonai Cai ◽  
Toshiro Ohashi
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Primary Cilia ◽  
Flexural Rigidity ◽  
Young's Modulus ◽  
Optical Trap ◽  
Mechanical Stimuli ◽  
Force Microscopy ◽  
Atomic Force

Mechanotransduction is a well-known mechanism by which cells sense their surrounding mechanical environment, convert mechanical stimuli into biochemical signals, and eventually change their morphology and functions. Primary cilia are believed to be mechanosensors existing on the surface of the cell membrane and support cells to sense surrounding mechanical signals. Knowing the mechanical properties of primary cilia is essential to understand their responses, such as sensitivity to mechanical stimuli. Previous studies have so far conducted flow experiments or optical trap techniques to measure the flexural rigidity EI (E: Young’s modulus, I: second moment of inertia) of primary cilia; however, the flexural rigidity is not a material property of materials and depends on mathematical models used in the determination, leading to a discrepancy between studies. For better characterization of primary cilia mechanics, Young’s modulus should be directly and precisely measured. In this study, the tensile Young’s modulus of isolated primary cilia is, for the first time, measured by using an in-house micro-tensile tester. The different strain rates of 0.01–0.3 s−1 were applied to isolated primary cilia, which showed a strain rate–dependent Young’s modulus in the range of 69.5–240.0 kPa on average. Atomic force microscopy was also performed to measure the local Young’s modulus of primary cilia, showing the Young’s modulus within the order of tens to hundreds of kPa. This study could directly provide the global and local Young’s moduli, which will benefit better understanding of primary cilia mechanics.

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