Artykuły w czasopismach: „Cell stretching device”

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Yadav, Sharda, Pradip Singha, Nhat-Khuong Nguyen, Chin Hong Ooi, Navid Kashaninejad i Nam-Trung Nguyen. "Uniaxial Cyclic Cell Stretching Device for Accelerating Cellular Studies". Micromachines 14, nr 8 (31.07.2023): 1537. http://dx.doi.org/10.3390/mi14081537.

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Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between the extracellular matrix and mechanical stress plays a significant role in organizing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as well as those capable of measuring the mechanical properties of biological cells, have greatly contributed to our understanding of fundamental mechanobiology. These tools have been extensively employed to unveil the substantial influence of mechanical cues on the development and progression of various diseases. In this report, we present an economical and high-performance uniaxial cell stretching device. This paper reports the detailed operation concept of the device, experimental design, and characterization. The device was tested with MDA-MB-231 breast cancer cells. The experimental results agree well with previously documented morphological changes resulting from stretching forces on cancer cells. Remarkably, our new device demonstrates comparable cellular changes within 30 min compared with the previous 2 h stretching duration. This third-generation device significantly improved the stretching capabilities compared with its previous counterparts, resulting in a remarkable reduction in stretching time and a substantial increase in overall efficiency. Moreover, the device design incorporates an open-source software interface, facilitating convenient parameter adjustments such as strain, stretching speed, frequency, and duration. Its versatility enables seamless integration with various optical microscopes, thereby yielding novel insights into the realm of mechanobiology.

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Huang, Lawrence, Pattie S. Mathieu i Brian P. Helmke. "A Stretching Device for High-Resolution Live-Cell Imaging". Annals of Biomedical Engineering 38, nr 5 (2.03.2010): 1728–40. http://dx.doi.org/10.1007/s10439-010-9968-7.

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Shao, Yue, Xinyu Tan, Roman Novitski, Mishaal Muqaddam, Paul List, Laura Williamson, Jianping Fu i Allen P. Liu. "Uniaxial cell stretching device for live-cell imaging of mechanosensitive cellular functions". Review of Scientific Instruments 84, nr 11 (listopad 2013): 114304. http://dx.doi.org/10.1063/1.4832977.

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HAYASHI, Tatsuya, Tasuku NAKAHARA, Katsuya SATO i Kazuyuki MINAMI. "Development of cell stretching micro device having micro chamber array". Proceedings of the Conference on Information, Intelligence and Precision Equipment : IIP 2016 (2016): E—2–5. http://dx.doi.org/10.1299/jsmeiip.2016.e-2-5.

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Kreutzer, Joose, Marlitt Viehrig, Risto-Pekka Pölönen, Feihu Zhao, Marisa Ojala, Katriina Aalto-Setälä i Pasi Kallio. "Pneumatic unidirectional cell stretching device for mechanobiological studies of cardiomyocytes". Biomechanics and Modeling in Mechanobiology 19, nr 1 (23.08.2019): 291–303. http://dx.doi.org/10.1007/s10237-019-01211-8.

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Sato, Kae, Manami Nitta i Aiko Ogawa. "A Microfluidic Cell Stretch Device to Investigate the Effects of Stretching Stress on Artery Smooth Muscle Cell Proliferation in Pulmonary Arterial Hypertension". Inventions 4, nr 1 (26.12.2018): 1. http://dx.doi.org/10.3390/inventions4010001.

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A microfluidic cell stretch device was developed to investigate the effects of stretching stress on pulmonary artery smooth muscle cell (PASMC) proliferation in pulmonary arterial hypertension (PAH). The microfluidic device harbors upper cell culture and lower control channels, separated by a stretchable poly(dimethylsiloxane) membrane that acts as a cell culture substrate. The lower channel inlet was connected to a vacuum pump via a digital switch-controlled solenoid valve. For cyclic stretch at heartbeat frequency (80 bpm), the open or close time for each valve was set to 0.38 s. Proliferation of normal PASMCs and those obtained from patients was enhanced by the circumferential stretching stimulation. This is the first report showing patient cells increased in number by stretching stress. These results are consistent with the abnormal proliferation observed in PAH. Circumferential stretch stress was applied to the cells without increasing the pressure inside the microchannel. Our data may suggest that the stretch stress itself promotes cell proliferation in PAH.

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Kamble, Harshad, Raja Vadivelu, Mathew Barton, Kseniia Boriachek, Ahmed Munaz, Sungsu Park, Muhammad Shiddiky i Nam-Trung Nguyen. "An Electromagnetically Actuated Double-Sided Cell-Stretching Device for Mechanobiology Research". Micromachines 8, nr 8 (22.08.2017): 256. http://dx.doi.org/10.3390/mi8080256.

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SHIMONO, Akihiro, Katsuya SATO i Kazuyuki MINAMI. "321 Fabrication of micro link mechanism for single cell stretching device". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2007.20 (2008): 119–20. http://dx.doi.org/10.1299/jsmebio.2007.20.119.

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MONJI, Ryo, Kazuyuki MINAMI, Yuta NAKASHIMA, Katsuya SATO i Keigo NAKANO. "716 Design and Fabrication of Highly Precise Cell Stretching Micro Device". Proceedings of Conference of Chugoku-Shikoku Branch 2011.49 (2011): 195–96. http://dx.doi.org/10.1299/jsmecs.2011.49.195.

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HAJI, Shigeyuki, Katsuya SATO i Kazuyuki MINAMI. "A211 Development of electro-static actuator for micro cell stretching device". Proceedings of the JSME Conference on Frontiers in Bioengineering 2007.18 (2007): 97–98. http://dx.doi.org/10.1299/jsmebiofro.2007.18.97.

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Kamble, Harshad, Matthew J. Barton i Nam-Trung Nguyen. "Modelling of an uniaxial single-sided magnetically actuated cell-stretching device". Sensors and Actuators A: Physical 252 (grudzień 2016): 174–79. http://dx.doi.org/10.1016/j.sna.2016.10.033.

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Tremblay, Dominique, Sophie Chagnon-Lessard, Maryam Mirzaei, Andrew E. Pelling i Michel Godin. "A microscale anisotropic biaxial cell stretching device for applications in mechanobiology". Biotechnology Letters 36, nr 3 (16.10.2013): 657–65. http://dx.doi.org/10.1007/s10529-013-1381-5.

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Michielin, F., E. Serena, P. Pavan i N. Elvassore. "Microfluidic-assisted cyclic mechanical stimulation affects cellular membrane integrity in a human muscular dystrophy in vitro model". RSC Advances 5, nr 119 (2015): 98429–39. http://dx.doi.org/10.1039/c5ra16957g.

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The development of a microfluidic-based cell stretching device allows to investigate membrane permeability during cyclic mechanical stimulation in a human Duchenne Muscular Dystrophy skeletal musclein vitromodel.

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SATO, Katsuya, Akihiro SHIMONO, Satoshi KAMADA i Kazuyuki MINAMI. "Novel Cell Stretching Micro Device for High Spatial and Temporal Resolution Observation". Transactions of the Japan Society of Mechanical Engineers Series C 74, nr 746 (2008): 2535–41. http://dx.doi.org/10.1299/kikaic.74.2535.

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NAGASE, Hiroaki, i Eiji IWASE. "Design of Stiffness Change Measuring Device for Cultured Cell under Stretching Stimulus". Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2017 (2017): 2P2—N01. http://dx.doi.org/10.1299/jsmermd.2017.2p2-n01.

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Huang, Yuli, i Nam-Trung Nguyen. "A polymeric cell stretching device for real-time imaging with optical microscopy". Biomedical Microdevices 15, nr 6 (19.07.2013): 1043–54. http://dx.doi.org/10.1007/s10544-013-9796-2.

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Fallahi, Hedieh, Haotian Cha, Hossein Adelnia, Yuchen Dai, Hang Thu Ta, Sharda Yadav, Jun Zhang i Nam-Trung Nguyen. "On-demand deterministic release of particles and cells using stretchable microfluidics". Nanoscale Horizons 7, nr 4 (2022): 414–24. http://dx.doi.org/10.1039/d1nh00679g.

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This paper reports a stretchable microfluidic cell trapper for the on-demand release of particles and cells in a deterministic manner. The size of particles to be trapped and released can be tuned by stretching the device.

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HAYASHI, Tatsuya, Tasuku NAKAHARA, Katsuya SATO i Kazuyuki MINAMI. "Developing of micro device with cell stretching micro chamber array having uniform thickness." Proceedings of Mechanical Engineering Congress, Japan 2016 (2016): S0210106. http://dx.doi.org/10.1299/jsmemecj.2016.s0210106.

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KAMADA, Satoshi, Akihiro SHIMONO, Kazuyuki MINAMI i Katsuya SATO. "530 Novel cell stretching micro device for high spatial and temporal resolution observation". Proceedings of the JSME annual meeting 2008.8 (2008): 259–60. http://dx.doi.org/10.1299/jsmemecjo.2008.8.0_259.

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SATO, Katsuya, Satsohi KAMADA i Kazuyuki MINAMI. "2E1-4 Development of MEMS device for real time observation of stretching cell". Proceedings of the JSME Symposium on Welfare Engineering 2009 (2009): 161–62. http://dx.doi.org/10.1299/jsmewes.2009.161.

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Thompson, Mark S., Stuart R. Abercrombie, Claus-Eric Ott, Friederike H. Bieler, Georg N. Duda i Yiannis Ventikos. "Quantification and significance of fluid shear stress field in biaxial cell stretching device". Biomechanics and Modeling in Mechanobiology 10, nr 4 (18.09.2010): 559–64. http://dx.doi.org/10.1007/s10237-010-0255-1.

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Davidovich, N., J. Huang i S. S. Margulies. "Reproducible uniform equibiaxial stretch of precision-cut lung slices". American Journal of Physiology-Lung Cellular and Molecular Physiology 304, nr 4 (15.02.2013): L210—L220. http://dx.doi.org/10.1152/ajplung.00224.2012.

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Simulating ventilator-induced lung injury (VILI) in the laboratory requires stretching of lung alveolar tissue. Whereas precision-cut lung slices (PCLSs) are widely used for studying paracrine signaling pathways in the lungs, their use in stretch studies is very limited because of the technical challenge of fixing them to a stretchable substrate, stretching them uniformly, or holding them in a stretch device without causing rupture. We describe a novel method for attaching PCLSs to silicone membranes by stitching them together in a star-shaped pattern. Using a device that was previously designed in our laboratory for stretching primary alveolar epithelial cell monolayers, we demonstrate that in the central region of the PCLSs stretch is uniform, equibiaxial, and, after a short preconditioning period, also reproducible. The stitched and stretched PCLSs showed equal or better viability outcomes after 60 min of cyclic stretch at different magnitudes of physiological stretch compared with primary pulmonary alveolar epithelial cell monolayers. Preparing and stitching the PCLSs before stretch is relatively easy to perform, yields repeatable outcomes, and can be used with tissue from any species. Together with the ensuring uniform and equibiaxial stretch, the proposed methods provide an optimal model for VILI studies with PCLSs.

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Holmes, David, Graeme Whyte, Joe Bailey, Nuria Vergara-Irigaray, Andrew Ekpenyong, Jochen Guck i Tom Duke. "Separation of blood cells with differing deformability using deterministic lateral displacement". Interface Focus 4, nr 6 (6.12.2014): 20140011. http://dx.doi.org/10.1098/rsfs.2014.0011.

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Determining cell mechanical properties is increasingly recognized as a marker-free way to characterize and separate biological cells. This emerging realization has led to the development of a plethora of appropriate measurement techniques. Here, we use a fairly novel approach, deterministic lateral displacement (DLD), to separate blood cells based on their mechanical phenotype with high throughput. Human red blood cells were treated chemically to alter their membrane deformability and the effect of this alteration on the hydrodynamic behaviour of the cells in a DLD device was investigated. Cells of defined stiffness (glutaraldehyde cross-linked erythrocytes) were used to test the performance of the DLD device across a range of cell stiffness and applied shear rates. Optical stretching was used as an independent method for quantifying the variation in stiffness of the cells. Lateral displacement of cells flowing within the device, and their subsequent exit position from the device were shown to correlate with cell stiffness. Data showing how the isolation of leucocytes from whole blood varies with applied shear rate are also presented. The ability to sort leucocyte sub-populations (T-lymphocytes and neutrophils), based on a combination of cell size and deformability, demonstrates the potential for using DLD devices to perform continuous fractionation and/or enrichment of leucocyte sub-populations from whole blood.

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Onoshima, Daisuke, Naoko Kawakita, Daiki Takeshita, Hirohiko Niioka, Hiroshi Yukawa, Jun Miyake i Yoshinobu Baba. "Measurement of DNA Length Changes upon CpG Hypermethylation by Microfluidic Molecular Stretching". Cell Medicine 9, nr 1-2 (styczeń 2017): 61–66. http://dx.doi.org/10.3727/215517916x693087.

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Abnormal DNA methylation in CpG-rich promoters is recognized as a distinct molecular feature of precursor lesions to cancer. Such unintended methylation can occur during in vitro differentiation of stem cells. It takes place in a subset of genes during the differentiation or expansion of stem cell derivatives under general culture conditions, which may need to be monitored in future cell transplantation studies. Here we demonstrate a microfluidic device for investigating morphological length changes in DNA methylation. Arrayed polymer chains of single DNA molecules were fluorescently observed by parallel trapping and stretching in the micro-fluidic channel. This observational study revealed that the shortened DNA length is due to the increased rigidity of the methylated DNA molecule. The trapping rate of the device for DNA molecules was substantially unaffected by changes in the CpG methylation.

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Trepat, Xavier, Mireia Grabulosa, Ferranda Puig, Geoffrey N. Maksym, Daniel Navajas i Ramon Farré. "Viscoelasticity of human alveolar epithelial cells subjected to stretch". American Journal of Physiology-Lung Cellular and Molecular Physiology 287, nr 5 (listopad 2004): L1025—L1034. http://dx.doi.org/10.1152/ajplung.00077.2004.

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Alveolar epithelial cells undergo stretching during breathing and mechanical ventilation. Stretch can modify cell viscoelastic properties, which may compromise the balance of forces in the alveolar epithelium. We studied the viscoelasticity of alveolar epithelial cells (A549) subjected to equibiaxial distention with a novel experimental approach. Cells were cultured on flexible substrates and subjected to stepwise deformations of up to 17% with a device built on an inverted microscope. Simultaneously, cell storage (G′) and loss (G″) moduli were measured (0.1–100 Hz) with optical magnetic twisting cytometry. G′ and G″ increased with strain up to 64 and 30%, respectively, resulting in a decrease in G″/G′ (15%). This stretch-induced response was inhibited by disruption of the actin cytoskeleton with latrunculin A. G′ increased with frequency following a power law with exponent α = 0.197. G″ increased proportionally to G′ but exhibited a more marked frequency dependence at high frequencies. Stretching (14%) caused a fall in α (13%). At high stretching amplitudes, actual cell strain (14.4%) was lower than the applied substrate strain (17.3%), which could indicate a partial cell detachment. These data suggest that cytoskeletal prestress modulates the elastic and frictional properties of alveolar epithelial cells in a coupled manner, according to soft glassy rheology. Stretch-induced cell stiffening could compromise the balance of forces at the cell-cell and cell-matrix adhesions.

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NAKANO, Keigo, Satoshi KAMADA, Katsuya SATO i Kazuyuki MINAMI. "711 Development of cell stretching micro device to observe cellular response to strain gradient field". Proceedings of Conference of Chugoku-Shikoku Branch 2009.47 (2009): 249–50. http://dx.doi.org/10.1299/jsmecs.2009.47.249.

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Noda, Kiyonori, i Hidehiro Oana. "Toward single-cell epigenome analysis: A microfluidic device for isolating, stretching, and imaging individual chromosomes". Sensors and Actuators B: Chemical 394 (listopad 2023): 134462. http://dx.doi.org/10.1016/j.snb.2023.134462.

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Benkherourou, M., C. Rochas, P. Tracqui, L. Tranqui i P. Y. Gume´ry. "Standardization of a Method for Characterizing Low-Concentration Biogels: Elastic Properties of Low-Concentration Agarose Gels". Journal of Biomechanical Engineering 121, nr 2 (1.04.1999): 184–87. http://dx.doi.org/10.1115/1.2835102.

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Low-concentration biogels, which provide an extracellular matrix for cells in vitro, are involved in a number of important cell biological phenomena, such as cell motility and cell differentiation. In order to characterize soft tissues, which collapse under their own weight, we developed and standardized a new experimental device that enabled us to analyze the mechanical properties of floating biogels with low concentrations, i.e., with values ranging from 2 g/L to 5 g/L. In order to validate this approach, the mechanical responses of free floating agarose gel samples submitted to compression as well as stretching tests were quantified. The values of the Young’s moduli, measured in the range of 1000 to 10,000 Pa, are compared to the values obtained from other experimental techniques. Our results showed indeed that the values we obtained with our device closely match those obtained independently by performing compression tests on an Instron device. Thus, the floating gel technique is a useful tool first to characterize and then to model soft tissues that are used in biological science to study the interaction between cell and extracellular matrix.

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Fraternali, Fernando, Narinder Singh, Ada Amendola, Gianmario Benzoni i Graeme W. Milton. "A biomimetic sliding–stretching approach to seismic isolation". Nonlinear Dynamics 106, nr 4 (2.11.2021): 3147–59. http://dx.doi.org/10.1007/s11071-021-06980-5.

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AbstractThere is growing demand in industrialized and developing countries to provide people and structures with effective earthquake protection. Here, we employ architectured material concepts and a bio-inspired approach to trail-blaze a new path to seismic isolation. We develop a novel seismic isolator whose unit cell is formed by linkages that replicate the bones of human limbs. Deformable tendons connect the limb members to a central post carrying the vertical load, which can slide against the bottom plate of the system. While the displacement capacity of the device depends only on the geometry of the limbs, its vibration period is tuned by dynamically stretching the tendons in the nonlinear stress–strain regime, so as to avoid resonance with seismic excitations. This biomimetic, sliding–stretching isolator can be scaled to seismically protect infrastructure, buildings, artworks and equipment with customized properties and sustainable materials. It does not require heavy industry or expensive materials and is easily assembled from metallic parts and 3D-printed components.

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Kim, Jaewon, Atsushi Tamura, Sachiko Tsukita i Sungsu Park. "Uniaxial stretching device for studying maturity-dependent morphological response of epithelial cell monolayers to tensile strain". Journal of Industrial and Engineering Chemistry 99 (lipiec 2021): 282–91. http://dx.doi.org/10.1016/j.jiec.2021.04.036.

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MONJI, Ryo, Kazuyuki MINAMI, Yuta NAKASHIMA i Katsuya SATO. "1019 Improvement of the precision of the fabrication and motion of the cell stretching micro device". Proceedings of Conference of Chugoku-Shikoku Branch 2013.51 (2013): _1019–1_—_1019–2_. http://dx.doi.org/10.1299/jsmecs.2013.51._1019-1_.

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Walker, Matthew, Michel Godin i Andrew E. Pelling. "Mechanical stretch sustains myofibroblast phenotype and function in microtissues through latent TGF-β1 activation". Integrative Biology 12, nr 8 (sierpień 2020): 199–210. http://dx.doi.org/10.1093/intbio/zyaa015.

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Abstract Developing methods to study tissue mechanics and myofibroblast activation may lead to new targets for therapeutic treatments that are urgently needed for fibrotic disease. Microtissue arrays are a promising approach to conduct relatively high-throughput research into fibrosis as they recapitulate key biomechanical aspects of the disease through a relevant 3D extracellular environment. In early work, our group developed a device called the MVAS-force to stretch microtissues while enabling simultaneous assessment of their dynamic mechanical behavior. Here, we investigated TGF-β1-induced fibroblast to myofibroblast differentiation in microtissue cultures using our MVAS-force device through assessing α-SMA expression, contractility and stiffness. In doing so, we linked cell-level phenotypic changes to functional changes that characterize the clinical manifestation of fibrotic disease. As expected, TGF-β1 treatment promoted a myofibroblastic phenotype and microtissues became stiffer and possessed increased contractility. These changes were partially reversible upon TGF-β1 withdrawal under a static condition, while, in contrast, long-term cyclic stretching maintained myofibroblast activation. This pro-fibrotic effect of mechanical stretching was absent when TGF-β1 receptors were inhibited. Furthermore, stretching promoted myofibroblast differentiation when microtissues were given latent TGF-β1. Altogether, these results suggest that external mechanical stretch may activate latent TGF-β1 and, accordingly, might be a powerful stimulus for continued myofibroblast activation to progress fibrosis. Further exploration of this pathway with our approach may yield new insights into myofibroblast activation and more effective therapeutic treatments for fibrosis.

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Gerstmair, Axel, Giorgio Fois, Siegfried Innerbichler, Paul Dietl i Edward Felder. "A device for simultaneous live cell imaging during uni-axial mechanical strain or compression". Journal of Applied Physiology 107, nr 2 (sierpień 2009): 613–20. http://dx.doi.org/10.1152/japplphysiol.00012.2009.

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Mechanical stimuli control multiple cellular processes such as secretion, growth, and differentiation. A widely used method to investigate cell strain ex vivo is stretching an elastic membrane to which cells adhere. However, simultaneous imaging of dynamic signals from single living cells grown on elastic substrates during uni-axial changes of cell length is usually hampered by the movement of the sample along the strain axis out of the narrow optical field of view. We used a thin, prestrained, elastic chamber as growth substrate for the cells and deformed the chamber with a computer-controlled stretch device. An algorithm that compensates the lateral displacement during stretch kept any selected point of the whole chamber at a constant position on the microscope during strain or relaxation (compression). Adherent cells or other materials that adhere to the bottom of the chamber at any given position could be imaged during controlled positive (stretch) or negative (compression) changes of cell length. The system was tested on living alveolar type II cells, in which mechanical effects on secretion have been intensively investigated in the past.

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NAKANO, Keigo, Katsuya SATO, Yuta NAKASHIMA i Kazuyuki MINAMI. "8H-05 Development of a cell stretching micro device to observe cellular response to strain gradient field". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2010.23 (2011): 151–52. http://dx.doi.org/10.1299/jsmebio.2010.23.151.

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Ahrens, Dave, Wolfgang Rubner, Ronald Springer, Nico Hampe, Jenny Gehlen, Thomas M. Magin, Bernd Hoffmann i Rudolf Merkel. "A Combined AFM and Lateral Stretch Device Enables Microindentation Analyses of Living Cells at High Strains". Methods and Protocols 2, nr 2 (24.05.2019): 43. http://dx.doi.org/10.3390/mps2020043.

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Mechanical characterization of living cells undergoing substantial external strain promises insights into material properties and functional principles of mechanically active tissues. However, due to the high strains that occur in physiological situations (up to 50%) and the complex structure of living cells, suitable experimental techniques are rare. In this study, we introduce a new system composed of an atomic force microscope (AFM), a cell stretching system based on elastomeric substrates, and light microscopy. With this system, we investigated the influence of mechanical stretch on monolayers of keratinocytes. In repeated indentations at the same location on one particular cell, we found significant stiffening at 25% and 50% strain amplitude. To study the contribution of intermediate filaments, we used a mutant keratinocyte cell line devoid of all keratins. For those cells, we found a softening in comparison to the wild type, which was even more pronounced at higher strain amplitudes.

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Huang, Wenjing, Sheng Zhang, Belal Ahmad i Tomohiro Kawahara. "Three-Motorized-Stage Cyclic Stretching System for Cell Monitoring Based on Chamber Local Displacement Waveforms". Applied Sciences 9, nr 8 (15.04.2019): 1560. http://dx.doi.org/10.3390/app9081560.

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Researchers have developed a cell stretching device to mimic the in vivo mechanical environment in vitro in order to investigate cell mechanotransduction. Cyclic stretch is involved in lengthening and relaxation phases. Cells may respond to mechanical stimulation rapidly within a few seconds, and sudden disruption of cell cytoskeletons may also occur at any point in any phase of cyclic stretch. However, until now, no research has been done to establish a method of collecting cell images at the two phases of cyclic stretch. Because image processing is time-consuming, it is difficult to adjust focus and collect high-resolution images simultaneously at the two phases during the process. In this study, a three-motorized-stage system was developed to meet the requirements. The results demonstrated that linear compensation is effective for cell imaging, and it is applicable to have a feed-forward control method without image processing. A method was then developed to determine the maximum displacement of the target in the horizontal and vertical directions, and the linear compensation waveforms were designed using the C program automatically and immediately before stretching. Further, the cyclic stretch was applied to cells using the three motorized stages, and clear phase-contrast cell imaging (30 fps) were obtained almost at any point in time. Detailed cell changes such as sudden disruption of cell–cell junctions, not only long-term cell response, were observed. Therefore, our study established a methodology to greatly improve the time resolution of imaging of cyclic stretch for the research of detailed cellular mechanotransduction.

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Peussa, Heidi, Joose Kreutzer, Elina Mäntylä, Antti-Juhana Mäki, Soile Nymark, Pasi Kallio i Teemu O. Ihalainen. "Pneumatic equiaxial compression device for mechanical manipulation of epithelial cell packing and physiology". PLOS ONE 17, nr 6 (3.06.2022): e0268570. http://dx.doi.org/10.1371/journal.pone.0268570.

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It is well established that mechanical cues, e.g., tensile- compressive- or shear forces, are important co-regulators of cell and tissue physiology. To understand the mechanistic effects these cues have on cells, technologies allowing precise mechanical manipulation of the studied cells are required. As the significance of cell density i.e., packing on cellular behavior is beginning to unravel, we sought to design an equiaxial cell compression device based on our previously published cell stretching system. We focused on improving the suitability for microscopy and the user-friendliness of the system. By introducing a hinge structure to the substrate stretch generating vacuum chamber, we managed to decrease the z-displacement of the cell culture substrate, thus reducing the focal plane drift. The vacuum battery, the mini-incubator, as well as the custom-made vacuum pressure controller make the experimental setup more flexible and portable. Furthermore, we improved the efficiency and repeatability of manufacture of the device by designing a mold that can be used to cast the body of the device. We also compared several different silicone membranes, and chose SILPURAN® due to its best microscopy imaging properties. Here, we show that the device can produce a maximum 8.5% radial pre-strain which leads to a 15% equiaxial areal compression as the pre-strain is released. When tested with epithelial cells, upon compression, we saw a decrease in cell cross-sectional area and an increase in cell layer height. Additionally, before compression the cells had two distinct cell populations with different cross-sectional areas that merged into a more uniform population due to compression. In addition to these morphological changes, we detected an alteration in the nucleo-cytoplasmic distribution of YAP1, suggesting that the cellular packing is enough to induce mechanical signaling in the epithelium.

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Barbee, Kenneth A. "Loading-Rate Dependent Cell Injury: A Design Criterion for Engineered Tissue Constructs". Microscopy and Microanalysis 6, S2 (sierpień 2000): 984–85. http://dx.doi.org/10.1017/s1431927600037417.

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Vascular endothelial cells experience a wide range of mechanical stimuli in vivo, including dynamic stretching and time-varying shear stress due to pulsatile blood flow. Under physiologic conditions, these hemodynamic forces constitute an important component of the cells' environment and are necessary for the normal maintenance of the structure and function of the vessel wall. Implantation of artificial vascular graft materials can significantly alter the mechanical environment of the cell. Furthermore, an important design criterion for engineered tissue constructs is the production of a mechanical environment that, ideally, stimulates normal growth and structural adaptation and. At least, avoids extremes in mechanical loading that might cause cellular trauma. In this paper, we investigate the mechanical loading conditions associated with normal and pathological mechanotransduction and cellular injury with an emphasis on the loading rate dependence of the cellular responses.A custom designed cone-and-plate device] allows arbitrary cone velocity waveforms to be generated.

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Gerometta, R., A. C. Zamudio, D. P. Escobar i O. A. Candia. "Volume change of the ocular lens during accommodation". American Journal of Physiology-Cell Physiology 293, nr 2 (sierpień 2007): C797—C804. http://dx.doi.org/10.1152/ajpcell.00094.2007.

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During accommodation, mammalian lenses change shape from a rounder configuration (near focusing) to a flatter one (distance focusing). Thus the lens must have the capacity to change its volume, capsular surface area, or both. Because lens topology is similar to a torus, we developed an approach that allows volume determination from the lens cross-sectional area (CSA). The CSA was obtained from photographs taken perpendicularly to the lenticular anterior-posterior (A-P) axis and computed with software. We calculated the volume of isolated bovine lenses in conditions simulating accommodation by forcing shape changes with a custom-built stretching device in which the ciliary body-zonulae-lens complex (CB-Z-L) was placed. Two measurements were taken (CSA and center of mass) to calculate volume. Mechanically stretching the CB-Z-L increased the equatorial length and decreased the A-P length, CSA, and lens volume. The control parameters were restored when the lenses were stretched and relaxed in an aqueous physiological solution, but not when submerged in oil, a condition with which fluid leaves the lens and does not reenter. This suggests that changes in lens CSA previously observed in humans could have resulted from fluid movement out of the lens. Thus accommodation may involve changes not only in capsular surface but also in volume. Furthermore, we calculated theoretical volume changes during accommodation in models of human lenses using published structural parameters. In conclusion, we suggest that impediments to fluid flow between the aquaporin-rich lens fibers and the lens surface could contribute to the aging-related loss of accommodative power.

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Weafer, Fiona M., Sharon Duffy, Ines Machado, Gillian Gunning, Pasquale Mordasini, Ellen Roche, Peter E. McHugh i Michael Gilvarry. "Characterization of strut indentation during mechanical thrombectomy in acute ischemic stroke clot analogs". Journal of NeuroInterventional Surgery 11, nr 9 (19.01.2019): 891–97. http://dx.doi.org/10.1136/neurintsurg-2018-014601.

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BackgroundAlthough it is common practice to wait for an ‘embedding time’ during mechanical thrombectomy (MT) to allow strut integration of a stentriever device into an occluding thromboembolic clot, there is a scarcity of evidence demonstrating the value or optimal timing for the wide range of thrombus compositions. This work characterizes the behavior of clot analogs of varying fibrin and cellular compositions subject to indentation forces and embedding times representative of those imparted by a stentriever during MT. The purpose of this study is to quantify the effect of thrombus composition on device strut embedding, and to examine the precise nature of clot integration into a stentriever device at a microstructural level.MethodClot analogs with 0% (varying densities), 5%, 40%, and 80% red blood cell (RBC) content were created using ovine blood. Clot indentation behavior during an initial load application (loading phase) followed by a 5-min embedding time (creep phase) was analyzed using a mechanical tester under physiologically relevant conditions. The mechanism of strut integration was examined using micro-computed tomography (µCT) with an EmboTrap MT device (Cerenovus, Galway, Ireland) deployed in each clot type. Microstructural clot characteristics were identified using scanning electron microscopy (SEM).ResultsCompressive clot stiffness measured during the initial loading phase was shown to be lowest in RBC-rich clots, with a corresponding greatest maximum indentation depth. Meanwhile, additional depth achieved during the simulated embedding time was most pronounced in fibrin-rich clots. SEM imaging identified variations in microstructural mechanisms (fibrin stretching vs rupturing) which was dependent on fibrin:cellular content, while µCT analysis demonstrated the mechanism of strut integration was predominantly the formation of surface undulations rather than clot penetration.ConclusionsDisparities in indentation behavior between clot analogs were attributed to varying microstructural features induced by the cellular:fibrin content. Greater indentation was identified in clots with higher RBC content, but with an increased level of fibrin rupture, suggesting an increased propensity for fragmentation. Additional embedding time improves strut integration, especially in fibrin-rich clots, through the mechanism of fibrin stretching with the majority of additional integration occurring after 3 mins. The level of thrombus incorporation into the EmboTrap MT device (Cerenovus, Galway, Ireland) was primarily influenced by the stentriever design, with increased integration in regions of open architecture.

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Shao, Lei, Bingchu Pan, Ruxia Hou, Yuan Jin i Yudong Yao. "User-friendly microfluidic manufacturing of hydrogel microspheres with sharp needle". Biofabrication 14, nr 2 (7.03.2022): 025017. http://dx.doi.org/10.1088/1758-5090/ac57a5.

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Abstract Hydrogel microspheres are flexible microstructures with many fascinating functions, such as three-dimensional cell culture, injection therapy, drug delivery, organoids and microtissues construction. The traditional methods of manufacturing hydrogel microspheres more or less have some shortcomings, such as atomization/emulsion method with uneven sizes; piezoelectric-/thermal-/electric-assisted inkjet with high cell damage and unknown cell growth effects; microfluidic manufacturing with sophisticated microdevices etc, which lead to poor user experiences. Here, we designed a user-friendly microfluidic device to generate hydrogel microspheres with sharp needles that can be replaced at will. Specifically, a commercial tapered opening sharp needle was inserted into a transparent silicone tube with the tapered opening facing the upper wall of the silicone tube. Then, gelatin methacrylate (GelMA) solution and paraffin oil were pumped into the sharp needle and the silicone tube respectively. GelMA microdroplets were formed under the shear stress of the silicone tube and the oil phase, and after being photo-crosslinked in situ, GelMA microspheres with uniform and adjustable sizes can be generated. Due to the simplicity of our original device, heterogeneous microspheres such as Janus, core–shell and hollow microspheres can be easily manufactured by simple modification of the device. In addition, we demonstrated the strong flexibility and maneuverability of the microspheres through macroscopic free assembly. Finally, we prepared different cell-laden GelMA microspheres, and the cells showed stretching behavior similar to that in vivo after a short period culture, which indicated the high bioactivity of GelMA microspheres. Meanwhile, we cultured the Janus cell-laden GelMA microspheres and the assembly of cell-laden GelMA microspheres, where the cells stretched and interacted, demonstrating the potential of GelMA microspheres for co-culture and fabrication of large-scale tissue constructs. In view of the above results, our user-friendly microfluidic manufacturing method of hydrogel microspheres with sharp needles will provide great convenience to relevant researchers.

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Li, Zhengqiang, Junfa Zheng, Di Wan i Xiaoqin Yang. "Uniaxial Static Strain Promotes Osteoblast Proliferation and Bone Matrix Formation in Distraction Osteogenesis In Vitro". BioMed Research International 2020 (13.08.2020): 1–12. http://dx.doi.org/10.1155/2020/3906426.

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Objective. We aimed at investigating the effects of uniaxial static strain on osteoblasts in distraction osteogenesis (DO). Methods. To simulate the mechanical stimulation of osteoblasts during DO, 10% uniaxial static strain was applied to osteoblasts using a homemade multiunit cell stretching and compressing device. Before and after applying strain stimulation, the morphological changes of osteoblasts were observed by inverted phase-contrast microscopy, Coomassie blue staining, and immunofluorescence. Alkaline phosphatase (ALP) activity, mRNA levels (proliferating cell nuclear antigen [PCNA], ALP, Runx2, osteocalcin [OCN], collagen type I, hypoxia-inducible factor- [HIF-] 1α, and vascular endothelial growth factor [VEGF]), and protein levels (Runx2, OCN, collagen type I, HIF-1α, and VEGF) were evaluated by using ALP kit, real-time quantitative reverse transcription-polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay. Results. After the mechanical stimulation, the cytoskeleton microfilaments were rearranged, and the cell growth direction of the osteoblasts became ordered, with their direction being at an angle of about 45° from the direction of strain. The proliferation of osteoblasts and the expression levels of mRNA and protein of ALP, Runx2, OCN, collagen type I, HIF-1α, and VEGF were significantly higher than in the nonstretch control groups. Conclusion. Our homemade device can exert uniaxial static strain and promote the proliferation of osteoblasts and bone matrix formation. It can be used to simulate the mechanical stimulation of osteoblasts during DO.

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Ghareaghaji, Ali. "Piezoelectric Nanowire toward Harvesting Energy from In-Vivo Environment". Bulletin of Electrical Engineering and Informatics 4, nr 1 (1.03.2015): 59–66. http://dx.doi.org/10.11591/eei.v4i1.327.

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This paper discusses technologies used to harvest energies from in-vivo environment. The discussion mainly concentrated on nanogenerators based on Piezoelectric nanowires which are employed for converting biomechanical energy (such as muscle stretching), vibration energy (such as heart rate sound, sound waves) and biohydraulic energy (such as blood flow, contraction of blood vessel) into electric energy. At the end this paper studies an approach for harvesting biomechanical and biochemical energies from living organisms simultaneously. This system, by using aligned nanowire arrays, can power medical nanosystems and nanodevices through converting vibration, biomechanical and biohydrulic energies into electricity. On the other hand by using biofuel cell structure, this hybrid cell can convert biochemical (glucose/O2) energy in biofluid into electricity. This technology can provide adequate power required for feeding nanodevices and nanosystems or at least to indirectly charge battery of the device. This technology can provide a sound basis for designing wireless self-powered nanodevices with direct energy harvesting from in-vivo environment.

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Kızılkurtlu, Ahmet Akif, Tuğçe Polat, Gül Banu Aydın i Ali Akpek. "Lung on a Chip for Drug Screening and Design". Current Pharmaceutical Design 24, nr 45 (16.04.2019): 5386–96. http://dx.doi.org/10.2174/1381612825666190208122204.

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Lung-on-a-chip is a micro device that combines the techniques of bioengineering, microbiology, polymer science and microfluidics disciplines in order to mimic physicochemical features and microenvironments, multicellular constructions, cell-cell interfaces of a human lung. Specifically, most novel lung on a chip designs consist of two micro-channeled outer parts, flexible and porous Polydimethylsiloxane (PDMS) membrane to create separation of air-blood chamber and subsidiary vacuum channels which enable stretching of the PDMS membrane to mimic movement mechanisms of the lung. Therefore, studies aim to emulate both tissue and organ functionality since it shall be creating great potential for advancing the studies about drug discovery, disease etiology and organ physiology compared with 2D (two dimensional) and 3D (three dimensional) cell culture models and current organoids. In this study, history of researches on lung anatomy and physiology, techniques of recreating lung functionality such as cell cultures in 2D and 3D models, organoids were covered and finally most advanced and recent state of the art technology product lung-on-a-chips’ construction steps, advantages compared with other techniques, usage in lung modeling and diseases, present and future offers were analyzed in detail.

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COOK, A. M., J. B. ROSENZWEIG, M. DUNNING, P. FRIGOLA i K. SERRATTO. "MITIGATION OF RF GUN BREAKDOWN BY REMOVAL OF TUNING RODS IN HIGH FIELD REGIONS". International Journal of Modern Physics A 22, nr 23 (20.09.2007): 4039–50. http://dx.doi.org/10.1142/s0217751x07037615.

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The π-mode resonant frequency of the 1.6 cell SLAC/BNL/UCLA style RF photoinjector electron gun is conventionally tuned using cylindrical copper tuning pieces that extend into the full-cell cavity through holes in the side of the gun. This design begins to fail in many versions of this popular gun design at higher voltage levels, when the cavity undergoes electric breakdown in the vicinity of the tuners. In order to remove the tuners from the region of high electric field, mitigating this problem, one must change the full cell geometry significantly. We have investigated a method for accomplishing this, in which we stretch the gun structure to tune the resonant frequency up by over 2 MHz. We constructed a device to perform this stretching and tested the modified photoinjector in an RF test bed. We succeeded in putting approximately 8.4 MW of RF power into the gun, an improvement over the 4 MW routinely achieved with a similar gun using conventional tuning methods installed at the UCLA Neptune laboratory. Recent results in testing this gun with a magnesium cathode insert are reported as well.

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TONELLO, SARAH, MICHELA BORGHETTI, NICOLA F. LOPOMO, MAURO SERPELLONI, EMILIO SARDINI, MARIAGRAZIA MARZIANO, MARIALAURA SERZANTI i in. "INK-JET PRINTED STRETCHABLE SENSORS FOR CELL MONITORING UNDER MECHANICAL STIMULI: A FEASIBILITY STUDY". Journal of Mechanics in Medicine and Biology 19, nr 06 (wrzesień 2019): 1950049. http://dx.doi.org/10.1142/s0219519419500490.

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Impedance-based sensors represent a promising tool for cell monitoring to improve current invasive biological assays. A novel research field is represented by measurements performed in dynamic conditions, monitoring cells (e.g., myocytes) for which the mechanical stimulus plays an important role for promoting maturation. In this picture, we applied printed and stretchable electronics principles, developing a system able to evaluate cells adhesion during substrate cyclic strain. Cytocompatible and stretchable sensors were ink-jet printed using carbon-based ink on crosslinked poly([Formula: see text]-caprolactone) electrospun mats. Moreover, a customized stretching device was produced, with a complete user interface to control testing condition, validated in order to correlate impedance changes with myoblasts — i.e., myocytes precursors — adhesion. Overall system sensitivity was evaluated using three different cell concentrations and DAPI imaging assay was performed to confirm myoblast adhesion. Preliminary results showed the possibility to correlate an average increase of impedance magnitude of 1[Formula: see text]k[Formula: see text] every 15,000 cells/cm2 seeded, suggesting the possibility to discriminate between different cell concentrations, with a sensitivity of 80[Formula: see text]m[Formula: see text]/(cells/cm2). In conclusion, the present system might be generalized in the development of future applications, including the differentiation process of cardiac myocytes with the aid of mechanical stimuli.

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Nath, Sanatan Kr, i Pradip Kumar Kalita. "Structural, Optical and Ionic Properties of PVA Capped CuS Quantum Dots". Journal of Nano Research 77 (30.03.2023): 119–33. http://dx.doi.org/10.4028/p-i9y6sp.

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Copper sulphide quantum dots were synthesized by a simple chemical route using ammonia (aq.) as a complexing agent in PVA matrix. Copper acetate monohydrate and thiourea were used as precursors. The particle sizes as obtained from XRD results were found to be in good agreement with those of HRTEM. The UV-Vis. absorption and PL emission spectra exhibited a systematic blue shift of absorption and emission respectively confirming quantum confinement effect in the synthesized quantum dots. The band gap as estimated from Tauc-plot increased from 3.26eV to 3.92eV with change of concentration of complexing agent. The FTIR spectra exhibited Cu-S stretching peaks characteristic of CuS. Ionic contributions of the electrolytic ionic CuS solution as measured by a standard conductivity cell clearly showed the semiconducting behavior of the product material. The synthesized material may be exploited in fabrication of an optoelectronic device in UV-blue region.

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Xue, Ziao, Li Wu, Junlin Yuan, Guodong Xu i Yuxiang Wu. "Self-Powered Biosensors for Monitoring Human Physiological Changes". Biosensors 13, nr 2 (7.02.2023): 236. http://dx.doi.org/10.3390/bios13020236.

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Human physiological signals have an important role in the guidance of human health or exercise training and can usually be divided into physical signals (electrical signals, blood pressure, temperature, etc.) and chemical signals (saliva, blood, tears, sweat). With the development and upgrading of biosensors, many sensors for monitoring human signals have appeared. These sensors are characterized by softness and stretching and are self-powered. This article summarizes the progress in self-powered biosensors in the past five years. Most of these biosensors are used as nanogenerators and biofuel batteries to obtain energy. A nanogenerator is a kind of generator that collects energy at the nanoscale. Due to its characteristics, it is very suitable for bioenergy harvesting and sensing of the human body. With the development of biological sensing devices, the combination of nanogenerators and classical sensors so that they can more accurately monitor the physiological state of the human body and provide energy for biosensor devices has played a great role in long-range medical care and sports health. A biofuel cell has a small volume and good biocompatibility. It is a device in which electrochemical reactions convert chemical energy into electrical energy and is mostly used for monitoring chemical signals. This review analyzes different classifications of human signals and different forms of biosensors (implanted and wearable) and summarizes the sources of self-powered biosensor devices. Self-powered biosensor devices based on nanogenerators and biofuel cells are also summarized and presented. Finally, some representative applications of self-powered biosensors based on nanogenerators are introduced.

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Amalina, Auliya Nur, Veinardi Suendo, Muhammad Reza, Phutri Milana, Risa Rahmawati Sunarya, Damar Rastri Adhika i Viny Veronika Tanuwijaya. "Preparation of Polyaniline Emeraldine Salt for Conducting-Polymer-Activated Counter Electrode in Dye Sensitized Solar Cell (DSSC) using Rapid-Mixing Polymerization at Various Temperature". Bulletin of Chemical Reaction Engineering & Catalysis 14, nr 3 (1.12.2019): 521. http://dx.doi.org/10.9767/bcrec.14.3.3854.521-528.

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Polyaniline Emeraldine Salt (PANI ES) as a conductive polymer has been used as a Pt-free counter electrode materials in DSSC. In this study, polymerization temperature was varied at relatively high temperature from 308 to 348 K with respect to the standard low polymerization temperature at 273 K. The synthesis held in varied high-temperature to study the effect of synthesis condition resulted to the performance as counter electrode in DSSC. The effect of high-temperature synthesis condition gives interesting results, the FTIR-ATR spectra show the presence of vibrational modes of phenazine structure obtained at high polymerization temperature, indicate the changing in the chain geometry. Raman Spectroscopy shows the decrease of the I1194/I1623 intensity ratio that can be interpreted that the degree-of-freedom of C-H bond bending mode decreases in the benzenoid ring, while the stretching mode degree-of-freedom along the chain is preserved or increased. The electrical conductivity profile has changed from metal-like at low-temperature into a semiconductor-like profile at high-temperature. Scanning Electron Microscope images reveals that a change in the morphology of PANI ES with temperature. At low-temperature (273 K) the morphology has a globular shape, while at high-temperature it tends to form nanorod structure. DSSC device with highest efficiency is attained for PANI ES polymerized at 273 K (1.91%) due to its high conductivity. The lowest efficiency is observed in device using PANI ES synthesized at 328 K (1.15%) due to its low conductivity due to the formation of phenazine structure. Copyright © 2019 BCREC Group. All rights reserved

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Huang, Chun-Ping, Chao-Min Cheng, Hong-Lin Su i Yi-Wen Lin. "Syndecan-4 Promotes Epithelial Tumor Cells Spreading and Regulates the Turnover of PKCα Activity under Mechanical Stimulation on the Elastomeric Substrates". Cellular Physiology and Biochemistry 36, nr 4 (2015): 1291–304. http://dx.doi.org/10.1159/000430297.

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Background: Heparan sulfate proteoglycans (HSPGs) at the cell surface play an important role in cell adhesion, spreading, formation of focal adhesion complexes (FACs), and sensing mechanical stress. Syndecans are members of the HSPGs family and are highly expressed in various tumor cells. Syndecan-4 (SDC4) is a unique member of syndecans that activates protein kinase C alpha (PKCα). However, syndecan-4 in tumor cells development is not clear when receiving mechanical stress. Aims: Here we investigate the role of syndecan-4 in tumor cells spreading and its downstream kinases under mechanical stimulation. Methods: Epithelial tumor cells were seeded onto elastomeric polydimethylsiloxane (PDMS) membranes coated with poly-L-lysine (Pl), fibronectin (Fn), or anti-SDC4 antibody and stretched with a modified pressure-driven cell-stretching (PreCS) device. Results: When cells received mechanical stimulation, engagement of syndecan-4 promoted the phosphorylation of focal adhesion kinase (FAK) at tyrosine 397 and PKCα at serine 657. Furthermore, we analyzed the cell contractility marker—myosin light chain 2 (MLC2) in 30 min time courses. The levels of phosphorylated MLC2 at serine19 were augmented through ligations of syndecan-4 but not integrin binding motif (RGD) at 10 min mechanical stimulation and were suppressed at 30 min and this phenomenon was associated with the activity of PKCα. Conclusion: Our data demonstrate that syndecan-4 is essential for transmitting the mechanotransduction signals via activation of PKCα and is important for tumor cells spreading, assembly of actin cytoskeleton and cell contractility.

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