The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Teruo Okano - One of the best experts on this subject based on the ideXlab platform.
-
Shear stress-dependent Cell Detachment from temperature-responsive Cell culture surfaces in a microfluidic device.
Biomaterials, 2012Co-Authors: Zhonglan Tang, Masayuki Yamato, Yoshikatsu Akiyama, Kazuyoshi Itoga, Jun Kobayashi, Teruo OkanoAbstract:Abstract A new approach to quantitatively estimate the interaction between Cells and material has been proposed by using a microfluidic system, which was made of poly(dimethylsiloxane) (PDMS) chip bonding on a temperature-responsive Cell culture surface consisted of poly( N -isopropylacrylamide) (PIPAAm) grafted tissue culture polystyrene (TCPS) (PIPAAm-TCPS) having five parallel test channels for Cell culture. This construction allows concurrently generating five different shear forces to apply to Cells in individual microchannels having various resistance of each channel and simultaneously gives an identical Cell incubation condition to all test channels. NIH/3T3 mouse fibroblast Cells (MFCs) and bovine aortic endothelial Cells (BAECs) were well adhered and spread on all channels of PIPAAm-TCPS at 37 °C. In our previous study, reducing culture temperature below the lower critical solution temperature (LCST) of PIPAAm (32 °C), Cells detach themselves from hydrated PIPAAm grafted surfaces spontaneously. In this study, Cell Detachment process from hydrated PIPAAm-TCPS was promoted by shear forces applied to Cells in microchannels. Shear stress-dependent Cell Detachment process from PIPAAm-TCPS was evaluated at various shear stresses. Either MFCs or BAECs in the microchannel with the strongest shear stress were found to be detached from the substrate more quickly than those in other microchannels. A Cell transformation rate constant C t and an intrinsic Cell Detachment rate constant k 0 were obtained through studying the effect of shear stress on Cell Detachment with a peeling model. The proposed device and quantitative analysis could be used to assess the possible interaction between Cells and PIPAAm layer with a potential application to design a Cell sheet culture surface for tissue engineering.
-
Cells adhesion Detachment control onto temperature responsive glass coverslips modified with ultra thin poly n isopropylacrylamide layer and its application of Cell Detachment process observed by tirf microscopy
International Symposium on Micro-NanoMechatronics and Human Science, 2008Co-Authors: Yoshitake Akiyama, Kazuhiro Fukumori, Masayuki Yamato, Kiyotaka Sakai, Teruo OkanoAbstract:Poly(N-isopropylacrylamide) (PIPAAm) was covalently grafted on glass coverslips (PIPAAm-CSs) by electron beam irradiation. Thickness and amount of the grafted polymer amount were increased with the initial monomer concentration. PIPAAm-CSs with thicker and larger amount of the grafted polymer exhibited more hydrophilic surfaces. When the monomer concentration was 5 wt%, the grafted polymer density was 0.84 mug/cm2, and Cells adhered, spread on the surface at 37degC, but detached at 20degC. In contrast, when the monomer concentration was 35 wt%, the polymer density was 1.28 mug/cm2, and the surfaces were Cell repellent even at 37degC. These results showed a remarkable contrast to those with temperature-responsive polymer-grafted tissue culture polystyrene dishes, since various types of Cells showed temperature-dependent Cell adhesion/Detachment when the grafted density was around 2 mug/cm2 on these surfaces. We discuss the possible molecular mechanisms underlying this discrepancy. Furthermore, we applied PIPAAm-CS surfaces to observation of Cell Detachment process by using total internal reflectance fluorescence (TIRF) microscopy.
-
copolymerization of 2 carboxyisopropylacrylamide with n isopropylacrylamide accelerates Cell Detachment from grafted surfaces by reducing temperature
Biomacromolecules, 2003Co-Authors: Mitsuhiro Ebara, Akihiko Kikuchi, Masayuki Yamato, Kiyotaka Sakai, Motohiro Hirose, Takao Aoyagi, Teruo OkanoAbstract:Acrylic acid (AAc) has been utilized to introduce reactive carboxyl groups to a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm). However, AAc introduction shifts the copolymer phase transition temperatures higher and dampens the steep homopolymer phase transition with increasing AAc content. We previously synthesized 2-carboxyisopropylacrylamide (CIPAAm) having both a similar side chain structure to IPAAm and a functional carboxylate group in order to overcome these shortcomings. In the present study, these copolymers, grafted onto Cell culture plastic, were assessed for Cell adhesion control using their phase transition. AAc introduction to PIPAAm-grafted surfaces resulted in excessive surface hydration and hindered Cell spreading in culture at 37 degrees C. In contrast, CIPAAm-containing copolymer-grafted surfaces exhibited relatively weak hydrophobicity similar to both homopolymer PIPAAm-grafted surfaces as well as commercial ungrafted tissue culture polystyrene dish surfaces. Cells adhered and spread well on these surfaces at 37 degrees C in culture. As observed previously on PIPAAm-grafted surfaces, Cells were spontaneously detached from the copolymer-grafted surfaces by reducing culture temperature. Cell Detachment was accelerated on the CIPAAm copolymer-grafted surfaces compared to pure IPAAm surfaces, suggesting that hydrophilic carboxyl group microenvironment in the monomer and polymer is important to accelerate grafted surface hydration below the lower critical solution temperature, detaching Cells.
-
Signal transduction and cytoskeletal reorganization are required for Cell Detachment from Cell culture surfaces grafted with a temperature- responsive polymer
Journal of Biomedical Materials Research, 1998Co-Authors: Masayuki Yamato, F. Karikusa, Masayuki Okuhara, Akihiko Kikuchi, Yasuhisa Sakurai, Teruo OkanoAbstract:We have developed a new Cell culture substrate grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm) using an electron beam irradiation method. These surfaces are hydrophobic in culture at 37 degrees C due to the hydration/dehydration changes intrinsic to PIPAAm at 32 degrees C, and they become highly hydrophilic below 32 degrees C. At 37 degrees C grafted and ungrafted surfaces showed no difference with regard to attachment, spreading, growth, confluent Cell density, and morphology of bovine aortic endothelial Cells. Stress fibers, peripheral bands, and focal contacts were established in similar ways. After the medium temperature was decreased to 20 degrees C, spread Cells lost their flattened morphology, acquiring a rounded Cell appearance similar to that of Cells immediately after plating. After mild agitation Cells floated free from the dish surface without trypsin treatment. Neither Cell morphological changes nor Cell Detachment occurred on ungrafted surfaces. An ATP synthesis inhibitor, sodium azide, and a tyrosine kinase inhibitor, genistein, suppressed Cell morphological changes and Cell Detachment while a protein synthesis inhibitor, cycloheximide, slightly enhanced Cell Detachment. An actin filament stabilizer, phalloidin, and its depolymerizer, cytochalasin D, also inhibited Cell Detachment. These findings suggest that Cell Detachment on grafted surfaces is mediated by intraCellular signal transduction and reorganization of the cytoskeleton. While trypsinization causes damage to the Cell membrane surface and extraCellular matrix proteins, this alternative low temperature treatment is exceptionally noninvasive. The temperature-responsive Cell culture surface also should prove useful for investigating the molecular machinery involved in Cell-surface Detachment.
-
mechanism of Cell Detachment from temperature modulated hydrophilic hydrophobic polymer surfaces
Biomaterials, 1995Co-Authors: Teruo Okano, Noriko Yamada, Minako Okuhara, Hideaki SakaiAbstract:Abstract Poly( N -isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 °C in physiological phosphate buffered saline solution (pH 7.4) and at 32 ° C in pure water, was grafted onto the surfaces of commercial polystyrene Cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial Cells and hepatocytes attached and proliferated on PIPAAmgrafted surfaces at 37 ° C, above the LCST. The cultured Cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for Cell Detachment was 10 ° C for hepatocytes and 20 ° C for endothelial Cells. Cell Detachment was partially inhibited by sodium azide treatment, suggesting that Cell metabolism directly affects Cell Detachment. Morphological changes of the adherent Cells during Cell Detachment experiments indicated further involvement of active Cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced Cell surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active Cell morphological changes which were a function of Cell metabolism.
Wenjian Weng - One of the best experts on this subject based on the ideXlab platform.
-
effects of rgd immobilization on light induced Cell sheet Detachment from tio2 nanodots films
Materials Science and Engineering: C, 2016Co-Authors: Kui Cheng, Wenjian Weng, Jun Lin, Hongping Wan, Tiantian Wang, Huiming WangAbstract:Light-induced Cell Detachment is reported to be a safe and effective Cell sheet harvest method. In the present study, the effects of arginine-glycine-aspartic acid (RGD) immobilization on Cell growth, Cell sheet construction and Cell harvest through light illumination are investigated. RGD was first immobilized on TiO2 nanodots films through simple physical adsorption, and then mouse pre-osteoblastic MC3T3-E1 Cells were seeded on the films. It was found that RGD immobilization promoted Cell adhesion and proliferation. It was also observed that Cells cultured on RGD immobilized films showed relatively high level of pan-cadherin. Cells harvested with ultraviolet illumination (365 nm) showed good viability on both RGD immobilized and unmodified TiO2 nanodot films. Single Cell Detachment assay showed that Cells detached more quickly on RGD immobilized TiO2 nanodot films. That could be ascribed to the RGD release after UV365 illumination. The current study demonstrated that RGD immobilization could effectively improve both the Cellular responses and light-induced Cell harvest.
-
improved light induced Cell Detachment on rutile tio nanodot films
Acta Biomaterialia, 2015Co-Authors: Kui Cheng, Wenjian Weng, Jun Lin, Yu Sun, Hongping Wan, Xiaozhao Wang, Huiming WangAbstract:Abstract Anatase TiO2 nanodot films have been found to be able to release Cells under light illumination with exCellent efficiency and safety. In the present study, we investigated the effects of rutile contents in TiO2 nanodot films on such light induced Cell Detachment behavior. The results showed that TiO2 nanodot films with different contents of rutile phase have been prepared successfully. The content of rutile phase increased with the increase in calcination temperature. All films possessed good Cell adhesion but there was a decrease in Cell proliferation with the increasing content of rutile phase. Single Cell Detachment assay showed that the films with high rutile contents (calcined at 900 °C and 1100 °C) showed better Cell Detachment performance. That was ascribed to the changes of the secondary structure of extraCellular proteins adsorbed on the nanodot surface after ultraviolet (365 nm, UV365) illumination. In addition, Cell sheets detached through UV365 illumination maintained high activity and could be further used in tissue engineering. The present work showed that the existence of rutile phase is helpful in Cell Detachment behavior and it could be utilized to optimize light-induced Cell Detachment behavior. Statement of Significance This work discovers that the presence of rutile phase in TiO2 nanodot films could improve the light-induced Cell Detachment behavior, although rutile phase is inferior to anatase phase on light induced superhydrophilicity. That strongly supported that the behaviors of adsorbed proteins are crucial in acquiring Cell sheet with light illumination. In fact, the state and behavior of adsorbed protein greatly affect the interaction between biomaterials and living Cells. Therefore, we consider this work is not only important in harvesting Cells or Cell sheets through light illumination, but also helpful in further understanding of interaction between biomaterials and Cells.
-
light induced Cell Detachment for Cell sheet technology
Biomaterials, 2013Co-Authors: Yi Hong, Wenjian Weng, Kui Cheng, Huiming Wang, Jun LinAbstract:The phenomenon of light-induced Cell Detachment is reported. Mouse calvaria-derived, pre-osteoblastic (MC3T3-E1) Cells were cultured on a TiO(2) nanodot-coated quartz substrate. After 20 min of UV365 illumination, over 90% of the Cells would detach from the surface. Moreover, intact Cell sheets could be obtained in the same way. It was found that the as-obtained Cells showed good viability, and could be used for further culture processes and other applications. Also, biocompatibility and safety characterizations indicated that the use of TiO(2) nanodots and UV365 illumination was safe for such Cell Detachment. It is suggested that adsorbed extraCellular matrix proteins play key roles in developing Cell sheets and ensuring biocompatibility. The present light-induced Cell Detachment method demonstrates a promising way for rapid Cell/Cell sheet harvesting.
Masae Sumita - One of the best experts on this subject based on the ideXlab platform.
-
quantitative evaluation of Cell attachment to glass polystyrene and fibronectin or collagen coated polystyrene by measurement of Cell adhesive shear force and Cell Detachment energy
Journal of Biomedical Materials Research, 2000Co-Authors: Akiko Yamamoto, Shuzo Mishima, Norio Maruyama, Masae SumitaAbstract:Quantitative evaluation of a material's affinity for Cells is essential to understanding Cell–material interaction inside a body and it is also necessary for the development of new biomaterials with superior biocompatibility. In the present study, the shear force and the total energy necessary to detach a single murine fibroblast L929 adhering to glass, polystyrene, and fibronectin- or collagen-coated polystyrene were measured directly by applying a lateral force, using a cantilever, to the Cell. The projected area of the Cell was also measured, and then Cell adhesive shear strength and Cell Detachment surface energy were determined by dividing the shear force and the total energy by the area. Among these four materials, the Cells on collagen-coated polystyrene have the highest Cell adhesive shear strength and Cell Detachment surface energy (1500 Pa and 29 pJ on average, respectively), followed by the Cells on fibronectin-coated polystyrene (1000 Pa and 16 pJ, respectively). The Cells on glass and polystyrene had almost the same Cell adhesive shear strength and Cell Detachment surface energy (420–670 Pa and 7–11 pJ, respectively). These observations suggest that Cell adhesive shear strength and Cell Detachment surface energy depend on the number of the bindings between the Cell and a material's surface rather than on the strength of each binding. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 50, 114–124, 2000.
-
quantitative evaluation of Cell attachment to glass polystyrene and fibronectin or collagen coated polystyrene by measurement of Cell adhesive shear force and Cell Detachment energy
Journal of Biomedical Materials Research, 2000Co-Authors: Akiko Yamamoto, Shuzo Mishima, Norio Maruyama, Masae SumitaAbstract:Quantitative evaluation of a material's affinity for Cells is essential to understanding Cell-material interaction inside a body and it is also necessary for the development of new biomaterials with superior biocompatibility. In the present study, the shear force and the total energy necessary to detach a single murine fibroblast L929 adhering to glass, polystyrene, and fibronectin- or collagen-coated polystyrene were measured directly by applying a lateral force, using a cantilever, to the Cell. The projected area of the Cell was also measured, and then Cell adhesive shear strength and Cell Detachment surface energy were determined by dividing the shear force and the total energy by the area. Among these four materials, the Cells on collagen-coated polystyrene have the highest Cell adhesive shear strength and Cell Detachment surface energy (1500 Pa and 29 pJ on average, respectively), followed by the Cells on fibronectin-coated polystyrene (1000 Pa and 16 pJ, respectively). The Cells on glass and polystyrene had almost the same Cell adhesive shear strength and Cell Detachment surface energy (420-670 Pa and 7-11 pJ, respectively). These observations suggest that Cell adhesive shear strength and Cell Detachment surface energy depend on the number of the bindings between the Cell and a material's surface rather than on the strength of each binding.
Yasuhisa Sakurai - One of the best experts on this subject based on the ideXlab platform.
-
Signal transduction and cytoskeletal reorganization are required for Cell Detachment from Cell culture surfaces grafted with a temperature- responsive polymer
Journal of Biomedical Materials Research, 1998Co-Authors: Masayuki Yamato, F. Karikusa, Masayuki Okuhara, Akihiko Kikuchi, Yasuhisa Sakurai, Teruo OkanoAbstract:We have developed a new Cell culture substrate grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm) using an electron beam irradiation method. These surfaces are hydrophobic in culture at 37 degrees C due to the hydration/dehydration changes intrinsic to PIPAAm at 32 degrees C, and they become highly hydrophilic below 32 degrees C. At 37 degrees C grafted and ungrafted surfaces showed no difference with regard to attachment, spreading, growth, confluent Cell density, and morphology of bovine aortic endothelial Cells. Stress fibers, peripheral bands, and focal contacts were established in similar ways. After the medium temperature was decreased to 20 degrees C, spread Cells lost their flattened morphology, acquiring a rounded Cell appearance similar to that of Cells immediately after plating. After mild agitation Cells floated free from the dish surface without trypsin treatment. Neither Cell morphological changes nor Cell Detachment occurred on ungrafted surfaces. An ATP synthesis inhibitor, sodium azide, and a tyrosine kinase inhibitor, genistein, suppressed Cell morphological changes and Cell Detachment while a protein synthesis inhibitor, cycloheximide, slightly enhanced Cell Detachment. An actin filament stabilizer, phalloidin, and its depolymerizer, cytochalasin D, also inhibited Cell Detachment. These findings suggest that Cell Detachment on grafted surfaces is mediated by intraCellular signal transduction and reorganization of the cytoskeleton. While trypsinization causes damage to the Cell membrane surface and extraCellular matrix proteins, this alternative low temperature treatment is exceptionally noninvasive. The temperature-responsive Cell culture surface also should prove useful for investigating the molecular machinery involved in Cell-surface Detachment.
-
mechanism of Cell Detachment from temperature modulated hydrophilic hydrophobic polymer surfaces
Biomaterials, 1995Co-Authors: Teruo Okano, Noriko Yamada, Minako Okuhara, Hideaki Sakai, Yasuhisa SakuraiAbstract:Poly(N-isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 degrees C in physiological phosphate buffered saline solution (pH 7.4) and at 32 degrees C in pure water, was grafted onto the surfaces of commercial polystyrene Cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial Cells and hepatocytes attached and proliferated on PIPAAm-grafted surfaces at 37 degrees C, above the LCST. The cultured Cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for Cell Detachment was 10 degrees C for hepatocytes and 20 degrees C for endothelial Cells. Cell Detachment was partially inhibited by sodium azide treatment, suggesting that Cell metabolism directly affects Cell Detachment. Morphological changes of the adherent Cells during Cell Detachment experiments indicated further involvement of active Cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced Cell-surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active Cell morphological changes which were a function of Cell metabolism.
Hideaki Sakai - One of the best experts on this subject based on the ideXlab platform.
-
mechanism of Cell Detachment from temperature modulated hydrophilic hydrophobic polymer surfaces
Biomaterials, 1995Co-Authors: Teruo Okano, Noriko Yamada, Minako Okuhara, Hideaki SakaiAbstract:Abstract Poly( N -isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 °C in physiological phosphate buffered saline solution (pH 7.4) and at 32 ° C in pure water, was grafted onto the surfaces of commercial polystyrene Cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial Cells and hepatocytes attached and proliferated on PIPAAmgrafted surfaces at 37 ° C, above the LCST. The cultured Cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for Cell Detachment was 10 ° C for hepatocytes and 20 ° C for endothelial Cells. Cell Detachment was partially inhibited by sodium azide treatment, suggesting that Cell metabolism directly affects Cell Detachment. Morphological changes of the adherent Cells during Cell Detachment experiments indicated further involvement of active Cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced Cell surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active Cell morphological changes which were a function of Cell metabolism.
-
mechanism of Cell Detachment from temperature modulated hydrophilic hydrophobic polymer surfaces
Biomaterials, 1995Co-Authors: Teruo Okano, Noriko Yamada, Minako Okuhara, Hideaki Sakai, Yasuhisa SakuraiAbstract:Poly(N-isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 degrees C in physiological phosphate buffered saline solution (pH 7.4) and at 32 degrees C in pure water, was grafted onto the surfaces of commercial polystyrene Cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial Cells and hepatocytes attached and proliferated on PIPAAm-grafted surfaces at 37 degrees C, above the LCST. The cultured Cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for Cell Detachment was 10 degrees C for hepatocytes and 20 degrees C for endothelial Cells. Cell Detachment was partially inhibited by sodium azide treatment, suggesting that Cell metabolism directly affects Cell Detachment. Morphological changes of the adherent Cells during Cell Detachment experiments indicated further involvement of active Cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced Cell-surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active Cell morphological changes which were a function of Cell metabolism.