Bibliographies thématiques / Cell mechanics, nanoindentation

Littérature scientifique sur le sujet « Cell mechanics, nanoindentation »

Auteur : Grafiati
Publié le 10 mars 2023

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Articles de revues sur le sujet "Cell mechanics, nanoindentation"

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Adusumalli, Ramesh-Babu, William M. Mook, Raphael Passas, Patrick Schwaller et Johann Michler. « Nanoindentation of single pulp fibre cell walls ». Journal of Materials Science 45, no 10 (27 janvier 2010) : 2558–63. http://dx.doi.org/10.1007/s10853-010-4226-9.

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Li, Qing Lin, Han Ping Mao et Ping Ping Li. « Measurement of Micro-Mechanics Property of Cell Wall by Nano-Indention ». Applied Mechanics and Materials 105-107 (septembre 2011) : 1847–50. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1847.

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To investigate the micro-mechanics property of cucumber mesophyll cell wall, an experiment was conducted at nanolevel scale with the help of nanoindentation masurement system after the tissue of cucumber leaf has been treated of fixing,dehydrating,embedding,slicing for the mesophyll. Loading-unloading curve showed: the cell wall deformed elastically before the stress reach 1.0MPa, after that, the cell wall deformed plastically;It also can be seen in the range elastic deformation that the stress-strain is nonlinear relationship .
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Dragovich, Matthew, Jared Feindt, Daniel Altman, Cassandra Christman, Nathan DeRaymond, Ibrahim Hashmi, Adama Shaw et al. « Investigation of the Reliability of AFM Nanoindentation-Derived Measurements of Cell Mechanics ». Biophysical Journal 112, no 3 (février 2017) : 270a—271a. http://dx.doi.org/10.1016/j.bpj.2016.11.1466.

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Han, Liuyang, Xingling Tian, Tobias Keplinger, Haibin Zhou, Ren Li, Kirsi Svedström, Ingo Burgert, Yafang Yin et Juan Guo. « Even Visually Intact Cell Walls in Waterlogged Archaeological Wood Are Chemically Deteriorated and Mechanically Fragile : A Case of a 170 Year-Old Shipwreck ». Molecules 25, no 5 (3 mars 2020) : 1113. http://dx.doi.org/10.3390/molecules25051113.

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Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.
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Zhang, Bo, Yihan Guo, Xing'e Liu, Huiyu Chen, Shumin Yang et Yan'gao Wang. « Mechanical properties of the fiber cell wall in Bambusa pervariabilis bamboo and analyses of their influencing factors ». BioResources 15, no 3 (20 mai 2020) : 5316–27. http://dx.doi.org/10.15376/biores.15.3.5316-5327.

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The cell wall mechanical properties are an important indicator for evaluating the overall mechanical properties of natural bamboo fibers. Using the nanoindentation technique, the variation of the mechanical properties of the fiber cell wall of Bambusa pervariabilis culms with different ages and different positions (both radial and longitudinal) was studied. Moreover, x-ray diffraction (XRD) was employed to measure the microfibril angle (MFA), and the correlation between the MFA and the mechanical properties of the fiber cell wall. The results showed that there was a remarkable difference in the fiber cell wall mechanical properties at different ages and at different radial and longitudinal positions. However, at different ages and at different positions, the absolute value of variation of MFA was less than 1° and was very minor. Furthermore, there was no significant correlation between the fiber cell wall mechanics and MFA, indicating that the mechanical property of the fiber cell walls might be synergistically affected by many factors.
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Marcotti, Stefania, Gwendolen C. Reilly et Damien Lacroix. « Effect of cell sample size in atomic force microscopy nanoindentation ». Journal of the Mechanical Behavior of Biomedical Materials 94 (juin 2019) : 259–66. http://dx.doi.org/10.1016/j.jmbbm.2019.03.018.

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Arfsten, J., C. Bradtmöller, I. Kampen et A. Kwade. « Compressive testing of single yeast cells in liquid environment using a nanoindentation system ». Journal of Materials Research 23, no 12 (décembre 2008) : 3153–60. http://dx.doi.org/10.1557/jmr.2008.0383.

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Due to their versatility and accuracy, nanoindentation systems are increasingly used for the characterization of micron-sized particles. Single microbial cells (e.g., yeast cells) can be regarded as micron-sized, liquid-filled biological particles. Applying a nanoindentation system for the compressive testing of those cells offers many options, such as testing in liquid environment. However, diverse experimental problems have to be resolved, especially the visualization of the cells in liquid and the alignment of the surfaces between which the cell is compressed. Single yeast cells were tested using a nanoindenter equipped with a flat punch tip. The deformation behavior of the cells during loading as well as the shape recovery behavior during unloading was investigated. A bursting force was determined as the cell wall was failing at higher deformations. Moreover, the influence of the compression speed on the cell mechanical behavior was characterized.
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Wang, Xinzhou, Linguo Zhao, Bin Xu, Yanjun Li, Siqun Wang et Yuhe Deng. « Effects of accelerated aging treatment on the microstructure and mechanics of wood-resin interphase ». Holzforschung 72, no 3 (23 février 2018) : 235–41. http://dx.doi.org/10.1515/hf-2017-0068.

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AbstractPlywood panels prepared from loblolly pine with cured phenol resin (PF) and urea-formaldehyde resin (UF) were submitted to accelerated aging and the microstructures and mechanics of wood-resin interphase were studied by nanoindentation (NI) and nanoscale dynamic mechanical analysis (Nano-DMA). The mass loss (ML) of wood, PF and UF resins were 3.4, 5.0 and 4.6% after aging treatment, respectively, and a large amount of microcracks were observed on the surface of wood and resins after aging treatment, which also affected the static mechanics of the cell walls far from the interphase region and the resins in the interphase region. The elastic modulus (Er) and hardness (H) values of the cell wall decreased by 7.2 and 9.5%, respectively, against the untreated control. The storage and loss modulus of the resins decreased significantly after aging treatment. The significant inconsistency in the mechanics, shrinkage and swelling properties of wood cell wall and resin in the interphase region after aging treatment resulted in a decrease of about 47 and 51% on the average bonding strength of the plywood made of PF and UF resins, respectively.
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Yang, Wenjian, Damien Lacroix, Lay Poh Tan et Jinju Chen. « Revealing the nanoindentation response of a single cell using a 3D structural finite element model ». Journal of Materials Research 36, no 12 (7 janvier 2021) : 2591–600. http://dx.doi.org/10.1557/s43578-020-00004-5.

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AbstractChanges in the apparent moduli of cells have been reported to correlate with cell abnormalities and disease. Indentation is commonly used to measure these moduli; however, there is evidence to suggest that the indentation protocol employed affects the measured moduli, which can affect our understanding of how physiological conditions regulate cell mechanics. Most studies treat the cell as a homogeneous material or a simple core–shell structure consisting of cytoplasm and a nucleus: both are far from the real structure of cells. To study indentation protocol-dependent cell mechanics, a finite element model of key intracellular components (cortex layer, cytoplasm, actin stress fibres, microtubules, and nucleus) has instead been developed. Results have shown that the apparent moduli obtained with conical indenters decreased with increasing cone angle; however, this change was less significant for spherical indenters of increasing radii. Furthermore, the interplay between indenter geometry and intracellular components has also been studied, which is useful for understanding structure-mechanics-function relationships of cells.
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Wagner, Leopold, Thomas K. Bader et Karin de Borst. « Nanoindentation of wood cell walls : effects of sample preparation and indentation protocol ». Journal of Materials Science 49, no 1 (30 août 2013) : 94–102. http://dx.doi.org/10.1007/s10853-013-7680-3.

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Thèses sur le sujet "Cell mechanics, nanoindentation"

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Ramdon, Sanjay Kiran. « Nanoscale Characterization of Aged Li-Ion Battery Cathodes ». The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376625747.

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BARTOLOZZI, ALICE. « Single cell elastography from nanoindentation experiments ». Doctoral thesis, 2019. http://hdl.handle.net/2158/1160885.

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Cell mechanics is currently an exciting and active area of research, and it has great potential to provide a new and different outlook on pathologies and classical biological problems. It is known cells can actively sense and respond to a huge variety of mechanical signals. New different scientific branches are addressing the mechanisms underlying these processes of sens- ing and responding, called respectively mechanosensing and mechanotrans- duction. Mechanobiology is a novel field that stands at a meeting point among biology, bioengineering and physiscs and its purpose is to address these processes with a quantitative, model based approach. The increas- ing growth of mechanobiology has been supported by the advancement of new technologies, especially in measuring force. Indeed the exploitation of nanotechnology to the study of biological systems opened new avenues to- wards innovative approaches based on single cell mechanical characterization. Nanoindentation experiments played a major role in this process, and still do. This thesis aimed to find a simple and robust analytical procedure which can provide new insight in cell mechanical properties, starting from nanoin- dentation experiments, allowing to make inferences into the functional state of the cell. At the beginning the whole existing procedure was optimized to achieve a higher throughput. Then, an existing model, the most used in literature to describe cell mechanical properties, was extended, in order to increase and supplement the information gained from nanoindentation experiments. This new procedure, called Elastography, allowed to identify different stiffness layers into the single cell, putatively associated with inner components and compartments of the cell. The Elastography was tested and proved to work both simulating the system and in experimental tests. Then it was applied in many different biological problems, to several coltures of different cell lines, in order to address specific questions about changes in cell mechanical properties.
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Meng, Yujie. « Methods for characterizing mechanical properties of wood cell walls via nanoindentation ». 2010. http://trace.tennessee.edu/utk_gradthes/731.

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Nanoindentation is a method of contacting a material whose mechanical properties are unknown with another material whose properties are known. Nanoindentation has the advantage of being able to probe a material’s microstructure while being sensitive enough to detect variations in mechanical properties. However, nanoindentation has some limitations as a testing technique due to the specific formation and structure of some biomaterials. The main objective of this research is to identify any factors that influence the nanoindentation measurement of wood cell walls (a typical biomaterial).The function of the embedding media in describing the properties of wood cells is poorly understood. This research demonstrated that Spurr’s resin, when diffused into wood cell wall during the embedding process, enhanced both the Young’s modulus and hardness of the cell walls. A substitute sample preparation method was developed to avoid this resin penetration into cell wall and was determined to be both effective and easy to perform.The nanoindentation procedure involves the application of a monitor and an analysis of the load-displacement behavior and the response in the material. It can be anticipated that various ways of loading, including the maximum force, the loading time, and others, will cause a variety of mechanical properties. Thus, our second aim was to study the effect of load function on nanoindentation measurement in wood. It was discovered that a fast loading rate contributed to greater contact depth and lower hardness. Increasing the holding time decreased measured values for both Young’s modulus and hardness. However, no significant difference of Young’s modulus and hardness among three loading functions with different unloading rates.The final part of the research was to study the effect of moisture content on the micromechanical properties of wood material. Several nanoindentations were performed on the wood cell wall while varying the moisture content of wood. Results indicated that both the Young’s modulus and hardness decreased significantly with an increase of moisture content. A rheology model was developed to describe the nanoindentation behaviors of wood cell walls at different moisture contents. Five parameters were extracted from Burger’s model, and the relationships among those five parameters were quantified.
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Hsu, Tun-Chieh, et 徐敦傑. « Study on Nano Mechanical Properties of Softwood cell Walls by Nanoindentation ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/95591143439054709845.

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碩士
國立臺灣大學
森林環境暨資源學研究所
99
With the progress of technology, the trend of material science has shifted from macro-scale to micro-scale study. Atomic force microscopy (AFM), which probes via the Van der Waals force between atoms, can be applied in nanoindentation technology and have detailed analysis of the mechanical properties and the structure of materials. With the understanding of the surface properties and nanoindentation mechanics, we can make the best use of materials in academic research and industrial applications. It has large potential in both two fields. The S2 cell wall layer of common softwood species in Taiwan are studied through nanoindentation in our study. The micro-mechanics and biological properties such as lignin content and microfibril angles (MFA) are studied. The results indicate that there are high variability of the mechanical properties between early and latewood in micro-scale. It is affected by the differences of wood components and structures. Some plastic deformations may also exist due to the effect of indentation loading parameters. The trend of elastic modulus is close to the model calculation and the consideration of the geometry of indentation probes. It decreases with the increase of MFA, but shows a more gentle curve than macro study due to micro-scale observations. Furthermore, the hardness in micro scale is generally decrease with the increasing MFA, but some deviating samples exist. Considering the material properties of wood, we can infer that the micro hardness is affected by matrix, structure, and the inhomogenerous nature of wood. From the results of our study, the mechanical properties of wood in micro scale are much more complex than macro ones. And there is also high variability exist. The study on the mechanical properties of wood in micro scale still has large potential in the future. Our study provides a preliminary research on the material preparation and mechanical properties for the nanoindentation of Taiwanese tree species, which serves as references of further researches in the future.
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Chapitres de livres sur le sujet "Cell mechanics, nanoindentation"

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Němeček, Jiří. « Nanoindentation Applied to Closed-Cell Aluminium Foams ». Dans Solid Mechanics and Its Applications, 173–88. Dordrecht : Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6919-9_9.

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Mirabet, Vincent, Nelly Dubrulle, Léa Rambaud, Léna Beauzamy, Mathilde Dumond, Yuchen Long, Pascale Milani et Arezki Boudaoud. « NanoIndentation, an Plugin for the Quantification of Cell Mechanics ». Dans Methods in Molecular Biology, 97–106. New York, NY : Springer New York, 2021. http://dx.doi.org/10.1007/978-1-0716-1816-5_6.

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Boccaccio, Antonio, Michele Fiorentino, Vito Modesto Manghisi, Giuseppe Monno et Antonio E. Uva. « Effect of Cell Shape on Nanoindentation Measurements ». Dans Lecture Notes in Mechanical Engineering, 37–44. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31154-4_4.

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Actes de conférences sur le sujet "Cell mechanics, nanoindentation"

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Xu, Yun-Yun, Shan-Dan Zhou et Tao Zhang. « Application of Nanoindentation Technology in Determining the Mechanical Properties of Wood Cell Wall ». Dans 2016 International Conference on Mechanics and Materials Science (MMS2016). WORLD SCIENTIFIC, 2017. http://dx.doi.org/10.1142/9789813228177_0058.

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Clausner, A., S. Schlipf, G. Kurz, M. Otto, J. Paul, K. U. Giering, J. Warmuth et al. « Analysis of 28 nm SRAM cell stability under mechanical load applied by nanoindentation ». Dans 2018 IEEE International Reliability Physics Symposium (IRPS). IEEE, 2018. http://dx.doi.org/10.1109/irps.2018.8353607.

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Whitcomb, Julie E., Rouzbeh Amini, Narendra Simha et Victor H. Barocas. « Mechanical Properties of the Iris Dilator and Stroma Using Nanoindentation ». Dans ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206373.

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In certain disorders of the eye such as angle-closure glaucoma [1], pigment dispersion syndrome [2], and intra-operative floppy iris syndrome [3] the contour of the iris plays an important role. The active iris contour is determined by a combination of external stresses arising from the flow of the aqueous humor and internal stresses due to the passive and active components of the constituent tissues. For example, in angle closure, the iris bows anteriorly, and the abnormal shape and position of the iris are directly related to the blockage of aqueous humor outflow, increasing the intraocular pressure. While the interaction between the aqueous humor and iris has been studied [4], little is known about the effect of the components of the iris on the contour. The iris is composed of stroma, pigment epithelial cells, and two constituent muscles, the sphincter iridis and dilator pupillae (Fig1).
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Zhang, Jingzhou, et Timothy C. Ovaert. « Mechanical Property Determination of Bone Through Nanoindentation Testing and Finite Element Simulation ». Dans ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176801.

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Measurement of the mechanical properties of bone is important for estimation of the local mechanical response of bone cells to loading experienced on a larger scale. An increasing number of measurements of the hardness and Young’s modulus of bone tissue have been undertaken using nanoindentation [1,2]. However, testing conditions have not been uniform. The interactions that can occur between testing condition parameters were considered in this study, and average hardness and Young’s modulus were obtained as a function of indentation creep testing conditions (maximum load, loading/unloading rate (both equal in magnitude), load-holding time, and indenter shape).
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Pandya, Hardik J., Hyun Tae Kim et Jaydev P. Desai. « A Microscale Piezoresistive Force Sensor for Nanoindentation of Biological Cells and Tissues ». Dans ASME 2013 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/dscc2013-3994.

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We present the design and fabrication of a Micro-Electro-Mechanical Systems based piezoresistive cantilever force sensor as a potential candidate for micro/nano indentation of biological specimens such as cells and tissues. The fabricated force sensor consists of a silicon cantilever beam with a p-type piezoresistor and a cylindrical probing tip made from SU-8 polymer. One of the key features of the sensor is that a standard silicon wafer is used to make silicon-on-insulator (SOI), thereby reducing the cost of fabrication. To make SOI from standard silicon wafer the silicon film was sputtered on an oxidized silicon wafer and annealed at 1050 °C so as to obtain polycrystalline silicon. The sputtered silicon layer was used to fabricate the cantilever beam. The as-deposited and annealed silicon films were experimentally characterized using X-ray diffraction (XRD) and Atomic Force Microscopy (AFM). The annealed silicon film was polycrystalline with a low surface roughness of 3.134 nm (RMS value).
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Kotoka, Ruben, Sudheer Neralla, Sergey Yarmolenko, Devdas Pai et Jag Sankar. « Structural and Mechanical Properties of Mg/MgO and Mg/Al2O3 Nanolaminate Coating for Implant Applications ». Dans ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65410.

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Nanostructured magnesium coatings have the potential of enhancing the integration of implant to bone tissues due to their ability to regulate the functions of integrin, which modulates cell proliferation and differentiation. However, they are soft, ductile and have low wear resistance. These limitations prevent the practical use of Mg coatings for this application. However, application of Mg thin films in the form of nanolaminate coatings has been found to improve hardness as well as wear properties. In this study, Mg/MgO and Mg/Al2O3 nanolaminates with bilayer thicknesses (Λ) 10, 20, 40, 100, 200, 1000 nm were deposited on glass substrate using the reactive pulsed DC magnetron sputtering process. The Mg/MgO nanolaminates were developed from an Mg target. Λ was controlled by the duration of oxygen flow during the sputtering process. Values of Λ were obtained from low angle-XRD. We found that the rate of MgO deposition significantly depends on water vapor content in the chamber and that a partial base pressure of water below 10−8 Torr is required to achieve repeatable results. Structure and properties of multilayered coatings were studied by X-ray diffractometry, nanoindentation, SEM and AFM. At Λ < 100 nm, MgO and Mg have preferred orientations <200> and <002> respectively, while at higher Λ, other orientations are present in the XRD patterns. The nanoindentation results showed slightly higher hardness of Mg/MgO and Mg/Al2O3 nanolaminate coatings compared to that of pure Mg. Nanolaminates have high ductility compared to MgO and Al2O3. Nanolaminate coatings at Λ < 100 nm exhibit an improvement in the mechanical properties due to the presence of interfaces which act as barrier to dislocation movement.
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Pagano, Claudia, et Curtis R. Taylor. « Nanomechanical Property Analysis of Silica Aerogel ». Dans ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13271.

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Aerogels (AGs) are open-cell nanofoams. AGs are lightweight and possess high thermal and acoustic insulation properties. Due to their ∼ 90% porosity, AGs are very brittle and fragile, which inhibits its use for load-bearing applications. For this reason an area of open research is the study and improvement of the mechanical properties of aerogels without altering their unique properties. Due to the extreme brittleness and low applied stress that AGs can support, direct mechanical measurements of AGs are challenging. To date very few experiments have been carried out to characterize the mechanical properties of aerogels; in particular at small contact dimensions and ultralow loads (nN-μN). In this paper, silica aerogel has been studied by nanoindentation using a diamond Berkovich indenter. We characterize the elasticity, stiffness, and hardness of the material as a function of contact depth (≤ 500 nm) at ultralow loads. The modulus and hardness are shown to change with depth with moduli and hardness ranging from 15–23 MPa and 3.5–6.8 MPa, respectively.
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Zhang, Qingwei, Ioannis Neitzel, Vadym N. Mochalin, Isabel Knoke, David M. Wootton, Yury Gogotsi, Peter I. Lelkes et Jack G. Zhou. « PLLA-Nanodiamond Composites and Their Application in Bone Tissue Engineering ». Dans ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13336.

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Nanodiamond (ND) is an attractive nanomaterial for reinforcement of polymers [1] due to the ND’s superior mechanical and chemical properties, and low biotoxicity. A novel composite material has been produced for bone scaffolds utilizing the biodegradable polymer, poly(L-lactic acid) (PLLA), and octadecylamine-functionalized nanodiamond (ND-ODA) [2]. Composites were prepared by admixing to a PLLA/chloroform solution chloroform suspensions of ND-ODA at concentrations of 0, 1, 3, 5, 7, and 10 (w/w). Dispersion of ND-ODA in the composites was studied by transmission electron microscopy (TEM). The lower-resolution TEM micrograph of 1% wt ND-ODA/PLLA film (Fig. 1a) shows nanodiamond particles dispersed in PLLA film on amorphous carbon support. Due to long hydrocarbon chains of ODA the ND-ODA particles have good wettability with the PLLA so there is no segregation of ND-ODA and PLLA, and the polymer completely surrounds the particles. The high-resolution TEM image (Fig. 1b) shows ND crystals with attached organic material that can be ODA or PLLA. Nanoindentation tests show that the mechanical strength of ND-ODA/PLLA composites improves upon addition of ND (Table 1). Even at low concentrations (1% wt) the ND-ODA increased the hardness of the composite by 60% and Young’s modulus by 20% over neat PLLA. Based on our preliminary observations, we conclude that further additions of ND-ODA resulted in smaller changes with subsequent saturation in the mechanical properties at ∼7% wt (see Table 1). ND is relatively novel nanomaterial. Establishing its biocompatibility requires further studies, especially for modified ND. We studied the biocompatibility of 5–10nm ND and ND-ODA in experiments with a murine osteoblast cell line (7F2, from ATCC). Incubation of a cultured osteoblasts with 1–100μg/ml of ND or ND-ODA particles for 4 hours did not show much influence on the cell viability (Fig. 2), as inferred from an alamarBlue™ assay. To test the feasibility of ND-ODA/PLLA as a matrix material supporting cell growth, osteoblasts were cultured on the composites for 6 days. The attactment and proliferation of 7F2 cells on the scaffolds were assessed, respectively, by fluorescent nuclear staining with Hoechst 33258 and the alamarBlueTM assay. Our results showed that the addition of ND-ODA had only a negligibly small effect on cell proliferation, which is indicative of good biocompatibility of the composites (Fig. 3). The morphology of 7F2 cells growing on all ND-ODA/PLLA composite scaffolds was assessed by SEM. The data (not shown) confirm that the osteoblasts spread on the scaffolds similar to their spreading on TCP (tissue culture plastic). To summarize, the improved mechanical properties of the PLLA/ND-ODA composites and their good biocompatibility suggest that these materials may be suitable for applications in musculoskeletal tissue engineering.
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Zhang, Qingwei, Vadym Mochalin, Ioannis Neitzel, Yury Gogotsi, Peter I. Lelkes et Jack Zhou. « The Study on PLLA-Nanodiamond Composites for Surgical Fixation Devices ». Dans ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38287.

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Biopolymers have a great potential in biomedical engineering, having been used as scaffolds for hard and soft tissues, such as bone and blood vessels for many years. More recently biopolymers have also found applications in surgical fixation devices. Compared with conventional metal fixation devices, bone grafts and organ substitutes, biopolymer products have advantages of no long-term implant palpability or temperature sensitivity, predictable degradation to provide progressive bone loading and no stress shielding, all of which leads to a better bone healing, reduced patient trauma and cost, elimination of second surgery for implant removal, and fewer complications from infections. However lack of initial fixation strength and bioactivity are two major concerns which limited more widespread applications of biopolymers in orthopedic surgery. Nanodiamond is attractive for its use in reinforcement of composite materials due to their outstanding mechanical, chemical and biological properties. Nanotechnology shows us many innovations and it is generally accepted view that many could be further developed and applied in tissue engineering. In this work, we conduct poly(L-lactic acid) (PLLA) and octadecylamine functionalized nanodiamond (ND-ODA) composite research to optimize the polymer/ND interface, thus to reinforce the mechanical strength. Composites comprising PLLA matrix with embedded ND-ODA were prepared by mixing PLLA/chloroform solution with chloroform suspension of nanodiamonds at concentrations of 0–10 by weight percent. The dispersion of ND-ODA was observed by transmission electron microscopy (TEM). TEM micrographs show that ND-ODA can disperse uniformly in PLLA till 10% wt. Nanoindentation result shows the mechanical strength of ND-ODA/PLLA composites improving following increasing the concentration of ND-ODA in composites. The noncytotoxicity of ND-ODA was demonstrated on 7F2 Osteoblasts. To test the usefulness of ND-ODA/PLLA composites as scaffolds for supporting cell growth, 7F2 Osteoblasts were cultured on scaffolds for 6 days. The attachment and proliferation of 7F2 on all scaffolds were assessed by fluorescent nuclear staining with Hoechst 33258 and Alamar BlueTM assay. The results showed that the adding ND-ODA does small influence cell growth, which indicates the composites have good biocompatibility. The morphology of 7F2 cells growing on all ND-ODA/PLLA composite scaffolds was determined by SEM, which confirms the Osteoblasts spread on the scaffolds. All these results combined suggest that ND-ODA/PLLA might provide a novel composite suitable for surgical fixation devices.
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Hasseldine, Benjamin P. J., Chao Gao et Yaning Li. « Damage Initiation and Evolution of Panicum Miliaceum Seeds Under Compression ». Dans ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71826.

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Panicum Miliaceum (common millet) is an ancient crop and spread widely across the world. The high survivability and adaptability of this species is attributed to the unique structure of the seedcoat. Recently, it was found the seedcoat has a fascinating complex microstructure with star-shaped epidermis cells, articulated together via wavy suture interfaces, to form a compact jigsaw puzzle-like layer. To explore the damage initiation and evolution during quasi-static uniaxial compression, finite element simulations were performed for full seeds, and single seedcoat and kernels. A parametric study was conducted for the seedcoat and kernel to explore the relationship between material properties and damage. The material properties of the seedcoat and kernel were obtained by nanoindentation testing. A Hashin progressive damage material model was used to capture damage evolution of the seedcoat, combined with a damage plasticity model for the kernel. The simulation results show the capabilities in modeling the damage of seeds.
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Rapports d'organisations sur le sujet "Cell mechanics, nanoindentation"

1

Pailino, Lia, Lihua Lou, Alberto Sesena Rubfiaro, Jin He et Arvind Agarwal. Nanomechanical Properties of Engineered Cardiomyocytes Under Electrical Stimulation. Florida International University, octobre 2021. http://dx.doi.org/10.25148/mmeurs.009775.

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Engineered cardiomyocytes made of human-induced pluripotent stem cells (iPSC) present phenotypical characteristics similar to human fetal cardiomyocytes. There are different factors that are essential for engineered cardiomyocytes to be functional, one of them being that their mechanical properties must mimic those of adult cardiomyocytes. Techniques, such as electrical stimulation, have been used to improve the extracellular matrix's alignment and organization and improve the intracellular environment. Therefore, electrical stimulation could potentially be used to enhance the mechanical properties of engineered cardiac tissue. The goal of this study is to establish the effects of electrical stimulation on the elastic modulus of engineered cardiac tissue. Nanoindentation tests were performed on engineered cardiomyocyte constructs under seven days of electrical stimulation and engineered cardiomyocyte constructs without electrical stimulation. The tests were conducted using BioSoft™ In-Situ Indenter through displacement control mode with a 50 µm conospherical diamond fluid cell probe. The Hertzian fit model was used to analyze the data and obtain the elastic modulus for each construct. This study demonstrated that electrically stimulated cardiomyocytes (6.98 ± 0.04 kPa) present higher elastic modulus than cardiomyocytes without electrical stimulation (4.96 ± 0.29 kPa) at day 7 of maturation. These results confirm that electrical stimulation improves the maturation of cardiomyocytes. Through this study, an efficient nanoindentation method is demonstrated for engineered cardiomyocyte tissues, capable of capturing the nanomechanical differences between electrically stimulated and non-electrically stimulated cardiomyocytes.
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