The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Chang Mo Hwang - One of the best experts on this subject based on the ideXlab platform.
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simultaneous generation of Chemical Concentration and mechanical shear stress gradients using microfluidic osmotic flow comparable to interstitial flow
Lab on a Chip, 2009Co-Authors: Joong Yull Park, Chang Mo HwangAbstract:Cells are very sensitive to various microenvironmental cues, including mechanical stress and Chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here we describe a simple and versatile method to study the generation of Chemical Concentration and mechanical shear stress gradients in a single microfluidic chip. Our system uses an osmotic pump that produces very slow (Chemical Concentration. We also established a shear stress gradient passively via a circular channel in the interstitial level. For evaluation of the system, we used L929 mouse fibroblast cells and simultaneously exposed them to a mechanical stress gradient and a Chemical nutrient gradient. The interstitial shear stress level clearly affected cell alignment, mobility velocity, and attachment. At the same time, cell proliferation reflected nutrient Concentration level. Our system, which enables continuous and long-term culture of cells in a combined Chemical and mechanical gradient, provides physiologically realistic conditions and will be applicable to studies of cancer metastasis and stem cell differentiation.
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Simultaneous generation of Chemical Concentration and mechanical shear stress gradients using microfluidic osmotic flow comparable to interstitial flow.
Lab on a chip, 2009Co-Authors: Joong Yull Park, Chang Mo Hwang, Sung Ju Yoo, Sang Hoon LeeAbstract:Cells are very sensitive to various microenvironmental cues, including mechanical stress and Chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here we describe a simple and versatile method to study the generation of Chemical Concentration and mechanical shear stress gradients in a single microfluidic chip. Our system uses an osmotic pump that produces very slow (
Joong Yull Park - One of the best experts on this subject based on the ideXlab platform.
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simultaneous generation of Chemical Concentration and mechanical shear stress gradients using microfluidic osmotic flow comparable to interstitial flow
Lab on a Chip, 2009Co-Authors: Joong Yull Park, Chang Mo HwangAbstract:Cells are very sensitive to various microenvironmental cues, including mechanical stress and Chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here we describe a simple and versatile method to study the generation of Chemical Concentration and mechanical shear stress gradients in a single microfluidic chip. Our system uses an osmotic pump that produces very slow (Chemical Concentration. We also established a shear stress gradient passively via a circular channel in the interstitial level. For evaluation of the system, we used L929 mouse fibroblast cells and simultaneously exposed them to a mechanical stress gradient and a Chemical nutrient gradient. The interstitial shear stress level clearly affected cell alignment, mobility velocity, and attachment. At the same time, cell proliferation reflected nutrient Concentration level. Our system, which enables continuous and long-term culture of cells in a combined Chemical and mechanical gradient, provides physiologically realistic conditions and will be applicable to studies of cancer metastasis and stem cell differentiation.
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Simultaneous generation of Chemical Concentration and mechanical shear stress gradients using microfluidic osmotic flow comparable to interstitial flow.
Lab on a chip, 2009Co-Authors: Joong Yull Park, Chang Mo Hwang, Sung Ju Yoo, Sang Hoon LeeAbstract:Cells are very sensitive to various microenvironmental cues, including mechanical stress and Chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here we describe a simple and versatile method to study the generation of Chemical Concentration and mechanical shear stress gradients in a single microfluidic chip. Our system uses an osmotic pump that produces very slow (
Jinyi Wang - One of the best experts on this subject based on the ideXlab platform.
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Construction of oxygen and Chemical Concentration gradients in a single microfluidic device for studying tumor cell–drug interactions in a dynamic hypoxia microenvironment
Lab on a chip, 2013Co-Authors: Lei Wang, Wenming Liu, Yaolei Wang, Jianchun Wang, Rui Liu, Jinyi WangAbstract:Recent microfluidic advancements in oxygen gradients have greatly promoted controllable oxygen-sensitive cellular investigations at microscale resolution. However, multi-gradient integration in a single microfluidic device for tissue-mimicking cell investigation is not yet well established. In this study, we describe a method that can generate oxygen and Chemical Concentration gradients in a single microfluidic device via the formation of an oxygen gradient in a chamber and a Chemical Concentration gradient between adjacent chambers. The oxygen gradient dynamics were systematically investigated, and were quantitatively controlled using simple exchange between the aerial oxygen and the oxygen-free conditions in the gas-permeable polydimethylsiloxane channel. Meanwhile, the Chemical gradient dynamics was generated using a special channel-branched device. For potential medical applications of the established oxygen and Chemical Concentration gradients, a tumor cell therapy assessment was performed using two antitumor drugs (tirapazamine and bleomycin) and two tumor cell lines (human lung adenocarcinoma A549 cells and human cervical carcinoma HeLa cells). The results of the proof-of-concept experiment indicate the dose-dependent antitumor effect of the drugs and hypoxia-induced cytotoxicity of tirapazamine. We demonstrate that the integration of oxygen and Chemical Concentration gradients in a single device can be applied to investigating oxygen- and Chemical-sensitive cell events, which can also be valuable in the development of multi-gradient generating procedures and specific drug screening.
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construction of oxygen and Chemical Concentration gradients in a single microfluidic device for studying tumor cell drug interactions in a dynamic hypoxia microenvironment
Lab on a Chip, 2013Co-Authors: Lei Wang, Wenming Liu, Yaolei Wang, Jianchun Wang, Rui Liu, Jinyi WangAbstract:Recent microfluidic advancements in oxygen gradients have greatly promoted controllable oxygen-sensitive cellular investigations at microscale resolution. However, multi-gradient integration in a single microfluidic device for tissue-mimicking cell investigation is not yet well established. In this study, we describe a method that can generate oxygen and Chemical Concentration gradients in a single microfluidic device via the formation of an oxygen gradient in a chamber and a Chemical Concentration gradient between adjacent chambers. The oxygen gradient dynamics were systematically investigated, and were quantitatively controlled using simple exchange between the aerial oxygen and the oxygen-free conditions in the gas-permeable polydimethylsiloxane channel. Meanwhile, the Chemical gradient dynamics was generated using a special channel-branched device. For potential medical applications of the established oxygen and Chemical Concentration gradients, a tumor cell therapy assessment was performed using two antitumor drugs (tirapazamine and bleomycin) and two tumor cell lines (human lung adenocarcinoma A549 cells and human cervical carcinoma HeLa cells). The results of the proof-of-concept experiment indicate the dose-dependent antitumor effect of the drugs and hypoxia-induced cytotoxicity of tirapazamine. We demonstrate that the integration of oxygen and Chemical Concentration gradients in a single device can be applied to investigating oxygen- and Chemical-sensitive cell events, which can also be valuable in the development of multi-gradient generating procedures and specific drug screening.
Judith Rivlin - One of the best experts on this subject based on the ideXlab platform.
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A comprehensive mathematical model for transport of soil-dissolved Chemicals by overland flow
Journal of Hydrology, 2001Co-Authors: Rony Wallach, Galina Grigorin, Judith RivlinAbstract:The model developed in this study simulates the contamination of overland flow by soil Chemicals that reside near its surface during a surface runoff event. The model includes mass-balance equations for both water flow and Chemical transport in the soil profile and surface runoff. A rate-limited mass transfer through an overland-flow boundary layer at the soil overland flow interface controls the dissolved Chemical transfer from soil solution to overland flow, once formed. The model predicts water flow and Chemical transport in the soil profile prior to the rainfall ponding (when overland flow starts) and during the surface runoff event. The predictions of these variables, together with the total load to the surface runoff, were successfully compared with the measured data of Hubbard et al. [Trans. ASAE, 32(4) (1989) 1239]. Being physically based, the model was used to investigate the dependence of surface runoff pollution and its extent on the system hydrological parameters. A key factor on the availability of soil Chemicals to pollute the overland flow is their displacement by infiltrating water prior to runoff initiation. Being dependent on soil moisture prior to rainfall initiation and on rainfall intensity, a lower Chemical Concentration and a lower load in surface runoff are obtained for longer ponding times, ones that are associated with lower rainfall rates and initially drier soil profiles. During the surface runoff flow, the Chemical Concentration in overland flow at the slope outlet is affected by the contact time of an overland flow parcel with the soil surface. Thus, it increases for higher values of equilibrium time — tE, lower rainfall rates, slope gradients, and higher soil-surface roughness coefficients. These parameters have an inverse effect on the surface runoff Concentration by affecting the transfer coefficient of soil Chemical to overland flow. A different insight into the relationship between the relevant dynamic processes throughout the storm event is achieved by studying the transient variation of soil Chemical flux to overland flow, the Chemical flux at the slope outlet, and the change of Chemical mass in the overland flow.
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A comprehensive mathematical model for transport of soil-dissolved Chemicals by overland flow
Journal of Hydrology, 2001Co-Authors: Rony Wallach, Galina Grigorin, Judith RivlinAbstract:The model developed in this study simulates the contamination of overland flow by soil Chemicals that reside near its surface during a surface runoff event. The model includes mass-balance equations for both water flow and Chemical transport in the soil profile and surface runoff. A rate-limited mass transfer through an overland-flow boundary layer at the soil overland flow interface controls the dissolved Chemical transfer from soil solution to overland flow, once formed. The model predicts water flow and Chemical transport in the soil profile prior to the rainfall ponding (when overland flow starts) and during the surface runoff event. The predictions of these variables, together with the total load to the surface runoff, were successfully compared with the measured data of Hubbard et al. [Trans. ASAE, 32(4) (1989) 1239]. Being physically based, the model was used to investigate the dependence of surface runoff pollution and its extent on the system hydrological parameters. A key factor on the availability of soil Chemicals to pollute the overland flow is their displacement by infiltrating water prior to runoff initiation. Being dependent on soil moisture prior to rainfall initiation and on rainfall intensity, a lower Chemical Concentration and a lower load in surface runoff are obtained for longer ponding times, ones that are associated with lower rainfall rates and initially drier soil profiles. During the surface runoff flow, the Chemical Concentration in overland flow at the slope outlet is affected by the contact time of an overland flow parcel with the soil surface. Thus, it increases for higher values of equilibrium time — tE, lower rainfall rates, slope gradients, and higher soil-surface roughness coefficients. These parameters have an inverse effect on the surface runoff Concentration by affecting the transfer coefficient of soil Chemical to overland flow. A different insight into the relationship between the relevant dynamic processes throughout the storm event is achieved by studying the transient variation of soil Chemical flux to overland flow, the Chemical flux at the slope outlet, and the change of Chemical mass in the overland flow.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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Construction of oxygen and Chemical Concentration gradients in a single microfluidic device for studying tumor cell–drug interactions in a dynamic hypoxia microenvironment
Lab on a chip, 2013Co-Authors: Lei Wang, Wenming Liu, Yaolei Wang, Jianchun Wang, Rui Liu, Jinyi WangAbstract:Recent microfluidic advancements in oxygen gradients have greatly promoted controllable oxygen-sensitive cellular investigations at microscale resolution. However, multi-gradient integration in a single microfluidic device for tissue-mimicking cell investigation is not yet well established. In this study, we describe a method that can generate oxygen and Chemical Concentration gradients in a single microfluidic device via the formation of an oxygen gradient in a chamber and a Chemical Concentration gradient between adjacent chambers. The oxygen gradient dynamics were systematically investigated, and were quantitatively controlled using simple exchange between the aerial oxygen and the oxygen-free conditions in the gas-permeable polydimethylsiloxane channel. Meanwhile, the Chemical gradient dynamics was generated using a special channel-branched device. For potential medical applications of the established oxygen and Chemical Concentration gradients, a tumor cell therapy assessment was performed using two antitumor drugs (tirapazamine and bleomycin) and two tumor cell lines (human lung adenocarcinoma A549 cells and human cervical carcinoma HeLa cells). The results of the proof-of-concept experiment indicate the dose-dependent antitumor effect of the drugs and hypoxia-induced cytotoxicity of tirapazamine. We demonstrate that the integration of oxygen and Chemical Concentration gradients in a single device can be applied to investigating oxygen- and Chemical-sensitive cell events, which can also be valuable in the development of multi-gradient generating procedures and specific drug screening.
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construction of oxygen and Chemical Concentration gradients in a single microfluidic device for studying tumor cell drug interactions in a dynamic hypoxia microenvironment
Lab on a Chip, 2013Co-Authors: Lei Wang, Wenming Liu, Yaolei Wang, Jianchun Wang, Rui Liu, Jinyi WangAbstract:Recent microfluidic advancements in oxygen gradients have greatly promoted controllable oxygen-sensitive cellular investigations at microscale resolution. However, multi-gradient integration in a single microfluidic device for tissue-mimicking cell investigation is not yet well established. In this study, we describe a method that can generate oxygen and Chemical Concentration gradients in a single microfluidic device via the formation of an oxygen gradient in a chamber and a Chemical Concentration gradient between adjacent chambers. The oxygen gradient dynamics were systematically investigated, and were quantitatively controlled using simple exchange between the aerial oxygen and the oxygen-free conditions in the gas-permeable polydimethylsiloxane channel. Meanwhile, the Chemical gradient dynamics was generated using a special channel-branched device. For potential medical applications of the established oxygen and Chemical Concentration gradients, a tumor cell therapy assessment was performed using two antitumor drugs (tirapazamine and bleomycin) and two tumor cell lines (human lung adenocarcinoma A549 cells and human cervical carcinoma HeLa cells). The results of the proof-of-concept experiment indicate the dose-dependent antitumor effect of the drugs and hypoxia-induced cytotoxicity of tirapazamine. We demonstrate that the integration of oxygen and Chemical Concentration gradients in a single device can be applied to investigating oxygen- and Chemical-sensitive cell events, which can also be valuable in the development of multi-gradient generating procedures and specific drug screening.