43 results on '"Kazuaki Matsumura"'
Search Results
2. Enhanced proliferation and differentiation of human mesenchymal stem cells in the gravity‐controlled environment
- Author
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Tadashi Nakaji‐Hirabayashi, Kazuaki Matsumura, Reiichi Ishihara, Tatsuya Ishiguro, Hiromitsu Nasu, Masatsugu Kanno, Shunji Ichida, and Toshikatsu Hatashima
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Biomaterials ,Osteoblasts ,Osteogenesis ,Biomedical Engineering ,Humans ,Medicine (miscellaneous) ,Cell Differentiation ,Mesenchymal Stem Cells ,Bioengineering ,General Medicine ,Environment, Controlled ,Cells, Cultured ,Cell Proliferation - Abstract
Human bone marrow mesenchymal stem cells (hMSCs) present a promising cell source with the potential to be used for curing various intractable diseases, and it is expected that the development of regenerative medicine employing cell-based therapy would be significantly accelerated when such methods are established. For that, powerful methods for selective growth and differentiation of hMSCs should be developed.We developed an efficient method for hMSC proliferation and differentiation into osteoblasts and adipocytes using gravity-controlled environments.The results indicate that the average doubling time of hMSCs cultured in a regular maintenance medium under microgravity conditions (0.001 G) was 1.5 times shorter than that of cells cultured under natural gravity conditions (1.0 G). Furthermore, 99.2% of cells grown in the microgravity environment showed the expression of hMSC markers, as indicated by flow cytometry analysis. Osteogenic and adipogenic differentiation of hMSCs expanded in the microgravity environment was enhanced under microgravity and hypergravity conditions, respectively, as evidenced by the downregulation of hMSC markers and upregulation of osteoblast and adipocyte markers, respectively. Most cells differentiated into osteoblasts in the microgravity environment after 14 days (~80%) and adipocytes in the hypergravity environment after 12 days (~90%).Our results indicate that hMSC proliferation and selective differentiation into specific cell lineages could be promoted under microgravity or hypergravity conditions, suggesting that cell culture in the gravity-controlled environment is a useful method to obtain cell preparations for potential clinical applications.
- Published
- 2022
3. Polyethylene-glycol-modified zwitterionic polymer assisted protein aggregation arrest and refolding
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Alisha Debas, Kazuaki Matsumura, and Robin Rajan
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Chemistry (miscellaneous) ,Process Chemistry and Technology ,Materials Chemistry ,Biomedical Engineering ,Energy Engineering and Power Technology ,Chemical Engineering (miscellaneous) ,Industrial and Manufacturing Engineering - Abstract
The heat-induced aggregation of lysozyme was prevented when heated in the presence of poly-sulfobetaine and PEG copolymers, which were also effective in easing the refolding of the denatured protein.
- Published
- 2022
4. Polyampholyte‐Based Polymer Hydrogels for the Long‐Term Storage, Protection and Delivery of Therapeutic Proteins
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Robin Rajan, Nishant Kumar, Dandan Zhao, Xianda Dai, Keiko Kawamoto, and Kazuaki Matsumura
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Biomaterials ,Biomedical Engineering ,Pharmaceutical Science - Published
- 2023
5. Development of an efficient vitrification method for chondrocyte sheets for clinical application
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Ayuko Uchikura, Hiroshi Nagashima, Masato Sato, Miki Maehara, Asuka Hayashi, Hitomi Matsunari, Suong-Hyu Hyon, and Kazuaki Matsumura
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0301 basic medicine ,Materials science ,Biomedical Engineering ,DMSO, dimethyl sulfoxide ,Chondrocyte ,Cryopreservation ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,FBS, fetal bovine serum ,PBS, phosphate buffered saline ,Osteoarthritis ,medicine ,Sheet structure ,Vitrification ,lcsh:QH573-671 ,Cell sheet ,lcsh:R5-920 ,lcsh:Cytology ,EG, ethylene glycol ,Cell survival rate ,Clinical Practice ,030104 developmental biology ,medicine.anatomical_structure ,LN, liquid nitrogen ,Original Article ,lcsh:Medicine (General) ,030217 neurology & neurosurgery ,LN - Liquid nitrogen ,Developmental Biology ,Biomedical engineering - Abstract
Introduction Regenerative therapy using chondrocyte sheets is effective for osteoarthritis. The clinical application of chondrocyte sheet therapy is expected to be further advanced by the use of a feasible cryopreservation technique. Previously, we developed a chondrocyte sheet vitrification method; however, it was too complex to be used for routine clinical application. Here, we aimed to develop a prototype method for vitrifying chondrocyte sheets for clinical practice. Methods We developed a “circulating vitrification bag” as a container to process cell sheets for vitrification in an efficient and sanitary fashion. Moreover, we invented the “vitrification storage box”, which is useful for the vitrification of cell sheets, long-term preservation, and transportation. These devices were used to vitrify rabbit chondrocyte sheets, which were then assessed for their structural characteristics and the viability of the component cells after rewarming. Results In all cell sheet samples (n = 7) vitrified by the circulating vitrification bag method, the integrity of the sheet structure was maintained, and the cell survival rate was similar to that of non-vitrified samples (91.0 ± 2.9% vs. 90.0 ± 3.0%). Proteoglycan and type II collagen, which are major components of cartilage, were densely and evenly distributed throughout the chondrocyte sheet subjected to vitrification similarly to that observed in the non-vitrified sheet. After long-term storage using the vitrification storage box, the cell sheets maintained normal structure and cell viability (survival rate: 81.2 ± 1.0% vs. 84.3 ± 1.8%) compared to the non-vitrified sheet. Conclusion Our results indicate that the circulating vitrification bag method is an effective approach for realizing the clinical application of vitrified chondrocyte sheets. The vitrification storage box is also useful for the long-term preservation of vitrified cell sheets, further enhancing the feasibility of the clinical application of cryopreserved chondrocyte sheets., Highlights • We developed a new device and method for the cryopreservation of cell sheets. • The method and device efficacy were evaluated using vitrified rabbit chondrocyte sheets. • Our approach allows efficient clinical application of vitrified cell sheets.
- Published
- 2020
6. Cytosolic delivery of quantum dots mediated by freezing and hydrophobic polyampholytes in RAW 264.7 cells
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Sana Ahmed, Kazuaki Matsumura, Robin Rajan, Dandan Zhao, and Tadashi Nakaji-Hirabayashi
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Biocompatibility ,Endosome ,Cell Survival ,Polymers ,Ampholyte Mixtures ,Biomedical Engineering ,Biocompatible Materials ,02 engineering and technology ,Endosomes ,010402 general chemistry ,01 natural sciences ,Cell membrane ,Mice ,Adsorption ,Cytosol ,Freezing ,Quantum Dots ,medicine ,Animals ,General Materials Science ,Polylysine ,Particle Size ,chemistry.chemical_classification ,Macrophages ,technology, industry, and agriculture ,General Chemistry ,General Medicine ,Polymer ,Fibroblasts ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,equipment and supplies ,In vitro ,0104 chemical sciences ,medicine.anatomical_structure ,RAW 264.7 Cells ,chemistry ,Quantum dot ,Biophysics ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,Intracellular - Abstract
Quantum dots (QDs) can be delivered efficiently inside macrophages using a freeze-concentration approach. In this study, we introduced a new, facile, high concentration-based freezing technology of low toxicity. We also developed QD-conjugated new hydrophobic polyampholytes using poly-L-lysine (PLL), a naturally derived polymer, which showed sustained biocompatibility, stability over one week, and enhanced intracellular delivery. When freeze-concentration was applied, the QD-encapsulated hydrophobic polyampholytes showed a higher tendency to adsorb onto the cell membrane than the non-frozen molecules. Interestingly, we observed that the efficacy of adsorption of QDs on RAW 264.7 macrophages was higher than that on fibroblasts. Furthermore, the intracellular delivery of QDs using hydrophobic polyampholytes was higher than those of PLL and QDs. In vitro studies revealed the efficient endosomal escape of QDs in the presence of hydrophobic polyampholytes and freeze-concentration. Collectively, these observations indicated that the promising combination of freeze-concentration and hydrophobic polyampholytes may act as an effective and versatile strategy for the intracellular delivery of QDs, which can be used for biological diagnosis and therapeutic applications.
- Published
- 2019
7. Effect of dual‐drug‐releasing micelle–hydrogel composite on wound healing in vivo in full‐thickness excision wound rat model
- Author
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Monika Patel, Kazuaki Matsumura, and Tadashi Nakaji-Hirabayashi
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Male ,Drug ,Materials science ,media_common.quotation_subject ,0206 medical engineering ,Rat model ,Biomedical Engineering ,Neovascularization, Physiologic ,Inflammation ,dermal wound healing ,02 engineering and technology ,Micelle ,Rats, Sprague-Dawley ,Biomaterials ,chemistry.chemical_compound ,Re-Epithelialization ,In vivo ,medicine ,Animals ,Regeneration ,Micelle-hydrogel composite ,pH-sensitive release ,Micelles ,media_common ,Wound Healing ,dual-drug release ,integumentary system ,Superoxide Dismutase ,Regeneration (biology) ,Metals and Alloys ,Hydrogels ,Catalase ,021001 nanoscience & nanotechnology ,polypeptide hydrogel ,020601 biomedical engineering ,Disease Models, Animal ,Drug Liberation ,chemistry ,Granulation Tissue ,Ceramics and Composites ,Curcumin ,Collagen ,medicine.symptom ,Rheology ,0210 nano-technology ,Wound healing ,Biomedical engineering - Abstract
Wound healing is a complex process involving an intricate cascade of body responses. A composite dressing that would effectively target different stages of wound healing and regeneration is urgently needed. In the current study, we tested the efficacy of a previously prepared micelle-hydrogel composite loaded with two drugs, in full-thickness excision wound model in rat. We found that the composite elicited almost no inflammation and effectively enhanced healing at all stages of the healing process. An initial burst of the first drug, amphotericin B, eliminated any preliminary infection. This burst was followed by a gradual release of curcumin as the healing and anti-inflammatory agent. Better healing was observed in rats treated with the drug-loaded composites than in blank and control groups. Wounds showed up to 80% closure in the treated group, with high collagen deposition. Re-epithelialization and granulation were also better in the treated group than in the non-treated control and blank groups. Histopathological examination revealed that drug-loaded composites improved cutaneous wound healing and regeneration. In conclusion, the micelle-hydrogel composite is an effective dressing and might have major applications in wound healing. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1094-1106, 2019.
- Published
- 2019
8. Controlling the degradation of cellulose scaffolds with Malaprade oxidation for tissue engineering
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Xida Yuan, Tadashi Nakaji-Hirabayashi, Kazuaki Matsumura, and Wichchulada Chimpibul
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Biomedical Engineering ,Ionic Liquids ,Biocompatible Materials ,Aldehyde ,Cell Line ,symbols.namesake ,chemistry.chemical_compound ,Tissue engineering ,Animals ,General Materials Science ,Cellulose ,Cell Proliferation ,chemistry.chemical_classification ,Tissue Engineering ,Periodate ,Proteins ,General Chemistry ,General Medicine ,Biodegradation ,Maillard reaction ,chemistry ,Chemical engineering ,Ionic liquid ,symbols ,Adsorption ,Oxidation-Reduction ,Porosity ,Protein adsorption - Abstract
This study was conducted to develop biodegradable cellulose scaffolds by oxidising porous cellulose sponges for tissue engineering applications. Cellulose powder was dissolved in ionic liquid using a salt leaching method, and porous cellulose scaffolds of various pore sizes were prepared. The scaffolds were oxidised with periodate to introduce aldehyde at a rate controlled by the periodate concentration. Oxidised scaffolds exhibited weight loss in cell culture medium, but not in phosphate buffer. Therefore, we confirmed that Schiff base formation between the aldehyde and amino groups through a Maillard reaction triggered cellulose molecular degradation. The degradation rate was controlled by the oxidation degree, whereas the aldehyde content controlled protein adsorption and cell proliferation. Additionally, in vivo implantation tests revealed that optimising the oxidation ratio not only improved biodegradability but also reduced inflammation. In conclusion, our results suggest that simple oxidised cellulose is useful as a low-toxicity biodegradable scaffold.
- Published
- 2020
9. Biodegradable shape memory polymers functionalized with anti-biofouling interpenetrating polymer networks
- Author
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Kazuaki Matsumura, Tadashi Nakaji-Hirabayashi, I. Dueramae, Hiromi Kitano, and Miku Nishida
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chemistry.chemical_classification ,Materials science ,Biomedical Engineering ,02 engineering and technology ,General Chemistry ,General Medicine ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Contact angle ,chemistry.chemical_compound ,Shape-memory polymer ,Membrane ,chemistry ,Copolymer ,General Materials Science ,Interpenetrating polymer network ,Composite material ,0210 nano-technology ,Polyurethane ,Protein adsorption - Abstract
A novel type of shape memory polyurethane (SMPU) with high mechanical properties and biodegradability was constructed using a lactone copolymer (poly(e-caprolactone-co-γ-butyrolactone), PCLBL), a diol- or triol-based chain extender (1,5-pentanediol, glycerol and 2-amino-2-hydroxymethyl-1,3-propanediol) and a diisocyanate cross-linker (1,6-hexamethylene diisocyanate). All types of SMPUs possessed high mechanical properties, and the shape recovery test indicated that the SMPU sheets prepared using a triol-chain extender with an amine group recovered completely the original shape at 80 °C. Moreover, the degradation products of the SMPUs were innoxious, which is an important property for use in the biomedical field. Furthermore, the SMPU sheets were interpenetrated with a zwitterionic polymer, poly(carboxymethyl betaine) (PCMB), using the interpenetrating polymer network (IPN) method to additionally introduce an anti-biofouling property. Water contact angle measurements of the surface of PCMB-introduced SMPU sheets showed a drastic reduction from 87° to approximately 30° due to the exposure of the PCMB chains from the SMPU sheets. These SMPU-IPN sheets suppressed significantly both protein adsorption and cell adhesion. Consequently, the PCLBL-PU-based SMPUs interpenetrated with PCMB are promising materials for biomedical devices because of their high mechanical, shape memory, biodegradable, and anti-biofouling properties. These materials are expected to be applied to biomaterials such as embolization materials for aneurysms and a novel type of membrane for postoperative adhesion prevention.
- Published
- 2020
10. Comparative analysis of the cellular entry of polystyrene and gold nanoparticles using the freeze concentration method
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Sana Ahmed, Kazuaki Matsumura, and Koyo Okuma
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endocytic mechanism ,Confocal ,Sonication ,Cells ,Biomedical Engineering ,Nanoparticle ,Metal Nanoparticles ,02 engineering and technology ,polystyrene ,010402 general chemistry ,01 natural sciences ,Citric Acid ,Nanomaterials ,chemistry.chemical_compound ,Mice ,Adsorption ,Cryoprotective Agents ,Animals ,General Materials Science ,Dimethyl Sulfoxide ,Particle Size ,Cryopreservation ,Drug Carriers ,Chemistry ,Biological Transport ,Fibroblasts ,gold ,021001 nanoscience & nanotechnology ,Polystyrene nanoparticles ,Endocytosis ,0104 chemical sciences ,freeze concentration ,Colloidal gold ,Biophysics ,Polystyrenes ,nanoparticles ,Polystyrene ,0210 nano-technology - Abstract
Despite advances in nanoparticle delivery, established physical approaches, such as electroporation and sonication, result in cell damage, limiting their practical applications. In this study, we proposed a unique freeze concentration-based technique and evaluated the efficacy of the method using two types of nanoparticles: citrate-capped gold nanoparticles and carboxylated polystyrene nanoparticles. We further compared the internalisation behaviour of particles of various sizes with and without freezing. Confocal microscopic images showed that the uptake efficacy of 50 nm nanomaterials was greater than that of 100 nm particles. Polystyrene nanoparticles of 50 nm size had more favourable adsorption and internalisation behaviours compared to those of gold nanoparticles after freeze concentration. We also examined the possible endocytic pathways involved in the uptake of gold and polystyrene nanoparticles, and found that the route differed between non-frozen and frozen conditions. Overall, we determined the influence of the freeze concentration strategy on both nanomaterial internalisation and the endocytic uptake pathway. Our findings provide a mechanistic understanding of the internalisation of nanoparticles using a freezing approach and thereby contribute to further developments in nanotherapeutic applications.
- Published
- 2018
11. Freezing Assisted Gene Delivery Combined with Polyampholyte Nanocarriers
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Tadashi Nakaji-Hirabayashi, Takayoshi Watanabe, Kazuaki Matsumura, Takahiro Hohsaka, and Sana Ahmed
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0301 basic medicine ,Materials science ,Biomedical Engineering ,02 engineering and technology ,Gene delivery ,Biomaterials ,03 medical and health sciences ,chemistry.chemical_compound ,Succinylation ,polyampholytes ,Surface charge ,gene delivery ,Polyethylenimine ,Chromatography ,Electroporation ,endosome escape ,Transfection ,021001 nanoscience & nanotechnology ,030104 developmental biology ,freeze concentration ,chemistry ,Chemical engineering ,Agarose gel electrophoresis ,nanoparticles ,Nanocarriers ,0210 nano-technology - Abstract
Physical methodologies such as electroporation and the gene-gun technology have been widely used for transfection; however, their applicability is limited because they lead to cell damage and low cell viability. Therefore, to address these limitations we developed a new freeze concentration-based gene transfection system that provides enhanced in vitro gene delivery compared to that provided by the commercially available systems. The system employs a facile freeze concentration step, whereby cells are simply frozen to very low temperatures in the presence of polymer-pDNA complexes. As part of system development, we also synthesized a low toxicity polyethyleneimine (PEI)-based polyampholyte prepared through succinylation with butylsuccinic anhydride. In aqueous solution, this modified polyampholyte self-assembles to form small (20 nm diameter), positively charged (net surface charge of 35 mV), nanoparticles through a combination of hydrophobic and electrostatic interactions. Agarose gel electrophoresis analysis indicated that the polyampholyte nanoparticle was able to form a complex with pDNA that provided stability against nuclease degradation. Using transfection of HEK-293T cells, we demonstrated that a combination of polyampholyte: pDNA, at an appropriate ratio, and the freeze concentration method resulted in significant enhancement of GFP and luciferase expression compared to commercially available carriers. Endosomal escape of pDNA was also found to be increased when using the modified polyampholyte compared to branched PEI. This study suggests that the efficient combination of freeze concentration and the modified polyampholyte described here has great potential for in vitro gene therapy.
- Published
- 2017
12. Switchable release nano-reservoirs for co-delivery of drugs via a facile micelle-hydrogel composite
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Tatsuo Kaneko, Monika Patel, and Kazuaki Matsumura
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Materials science ,polypeptides ,micelles ,Composite number ,Biomedical Engineering ,Nanotechnology ,02 engineering and technology ,dual delivery ,010402 general chemistry ,01 natural sciences ,Micelle ,chemistry.chemical_compound ,Amphiphile ,Nano ,Side chain ,General Materials Science ,technology, industry, and agriculture ,General Chemistry ,General Medicine ,021001 nanoscience & nanotechnology ,Controlled release ,0104 chemical sciences ,Chemical engineering ,chemistry ,Drug delivery ,drug delivery ,Genipin ,0210 nano-technology - Abstract
Precise and controlled drug delivery systems are required to facilitate effective therapeutics. To address this need, we devised a micelle-hydrogel composite based on amphiphilic polypeptides as a general carrier model for the switchable and controlled release of dual drugs. Two different di-block polypeptides, poly (L-lysine-b-L- phenylalanine) and poly (L-glutamic acid-b-L-phenylalanine) (PGA-PPA), were synthesized to form distinct self-assembling micellar systems that were loaded with curcumin and amphotericin B, respectively, as model drugs. The drug-loaded micellar mixture was crosslinked utilizing the pendant amino groups of the L-lysine side chains via genipin to yield a micelle-hydrogel composite with PGA-PPA micelles trapped in the interlinked hydrogel system. This composite allowed for controlled multiphasic drug release and could be effectively tuned to moderate the pace and amount of drug release and be easily regulated to switch the drug release kinetics over a range of simple factors such as change in pH, cross-linking density, and composition.
- Published
- 2017
13. Cryopreservation of a two-dimensional monolayer using a slow vitrification method with polyampholyte to inhibit ice crystal formation
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Daisuke Tanaka, Kazuaki Matsumura, Shigehiro Yoshimura, Masahiro Takeuchi, Keiko Kawamoto, and Suong-Hyu Hyon
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0301 basic medicine ,Materials science ,Cryoprotectant ,Biomedical Engineering ,Nanotechnology ,02 engineering and technology ,cryopreservation ,polyampholyte ,Cryopreservation ,law.invention ,Biomaterials ,03 medical and health sciences ,chemistry.chemical_compound ,law ,Monolayer ,Vitrification ,Crystallization ,Thermal analysis ,021001 nanoscience & nanotechnology ,vitrification ,030104 developmental biology ,Devitrification ,chemistry ,ice crystallization ,tissue-engineered construct ,Biophysics ,0210 nano-technology ,Ethylene glycol - Abstract
Vitrification methods have been developed to improve the preservation of oocytes and embryos. However, successful vitrification and preservation typically requires very high cooling speeds. Here, we report a novel slow vitrification method for cryopreservation of two-dimensional (2D) cell constructs using a vitrification solution (VS) in PBS containing 6.5 M ethylene glycol, 0.5 M sucrose, and 10% w/w carboxylated poly-L-lysine (COOH-PLL), a novel polymeric cryoprotectant and stabilizing agent that is likely to inhibit ice crystallization. Stabilization of the glassy state and inhibition of devitrification was confirmed by thermal analysis using differential scanning calorimetry. The viability of cultured human mesenchymal stem cell (MSC) monolayers after freezing by our novel slow vitrification method at a rate of 4.9°C/min in VS with 10% COOH-PLL was significantly higher than that of cells frozen using our slow vitrification method in VS without COOH-PLL. Moreover, cells maintained the capacity for differentiation. We further confirmed that COOH-PLL improved the vitrification properties of the current vitrification system through inhibition of recrystallization properties. This novel, simple method for slow vitrification can be widely applicable for the preservation of tissue-engineered constructs and may facilitate the industrialization of regenerative medicine.
- Published
- 2016
14. Polyampholyte- and nanosilicate-based soft bionanocomposites with tailorable mechanical and cell adhesion properties
- Author
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Kazuaki Matsumura and Minkle Jain
- Subjects
Materials science ,Nanocomposite ,Mechanical Phenomena ,Metals and Alloys ,Biomedical Engineering ,02 engineering and technology ,Polyethylene glycol ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Controlled release ,0104 chemical sciences ,Biomaterials ,chemistry.chemical_compound ,Succinimide ,chemistry ,Chemical engineering ,Polylysine ,Self-healing hydrogels ,Ceramics and Composites ,Composite material ,0210 nano-technology ,Cell adhesion - Abstract
Engineered tissues are excellent substitutes for treating organ failure associated with disease, injury, and degeneration. Designing new biomaterials with controlled release profiles, good mechanical properties, and cell adhesion characteristics can be useful for the formation of specific functional tissues. Here, we report the formulation of nanocomposite hydrogels based on carboxylated poly-l-lysine and synthetic clay laponite XLG in which four-arm polyethylene glycol with N-hydroxy succinimide ester (PEG-NHS) was used as the chemical crosslinker. Interestingly, the degradation of this gel could be adjusted from a few days to a few months. Incorporation of laponite XLG resulted in the formation of mechanically tough hydrogels and conferred cytocompatibility. The mechanical properties of the nanocomposite could be modulated by changing the crosslinking density and laponite concentration. The feasibility of using this system for cellular therapies was investigated by evaluating cell adhesion on the nanocomposite surface. Thus, these nanocomposites can serve as scaffolds with tunable mechanical and degradation properties that also provide structural integrity to tissue constructs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1379-1386, 2016.
- Published
- 2016
15. A zwitterionic polymer as a novel inhibitor of protein aggregation
- Author
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Robin Rajan and Kazuaki Matsumura
- Subjects
chemistry.chemical_classification ,Biomedical Engineering ,Chain transfer ,General Chemistry ,General Medicine ,Polymer ,Raft ,Protein aggregation ,Random coil ,chemistry.chemical_compound ,chemistry ,Polymerization ,Biophysics ,Organic chemistry ,General Materials Science ,Lysozyme ,Solubility - Abstract
We report the novel one-step synthesis of a zwitterionic polymer, polysulfobetaine, via living reversible addition fragmentation chain transfer (RAFT) polymerization. Lysozyme did not aggregate when heated in the presence of this polymer. Amyloid formation, the cause of many diseases, was also suppressed. The zwitterionic polymer was significantly more efficient than previously described inhibitors of protein aggregation. Lysozyme heated in the presence of polysulfobetaine retained its solubility and very high enzymatic efficiency, even after prolonged heating. The secondary structures of lysozyme change with increasing temperature, accompanied by an increase in the β-structure. This change was prevented by mixing the polymer with lysozyme. 1H-NMR before and after aggregation revealed the conformational changes taking place in the lysozyme: during aggregation, lysozyme is transformed into a random coil conformation, thus losing its secondary structure. Presence of the polymer facilitates retention of partial higher order structures and lysozyme solubility at higher temperatures. The high efficiency of the polyampholyte was ascribed to its ability to prevent collisions between aggregating species by acting as a molecular shield.
- Published
- 2015
16. StemCell Keep™ is Effective for Cryopreservation of Human Embryonic Stem Cells by Vitrification
- Author
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Jun-Jae Lee, S.-H. Hyon, Akemi Ota, Kazuaki Matsumura, and Shoichiro Sumi
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0301 basic medicine ,Cryoprotectant ,Cell Culture Techniques ,Biomedical Engineering ,lcsh:Medicine ,Buffers ,Biology ,Stem cell marker ,Article ,Cryopreservation ,Flow cytometry ,03 medical and health sciences ,Cryoprotective Agents ,Acetamides ,medicine ,Humans ,Dimethyl Sulfoxide ,Embryonic Stem Cells ,reproductive and urinary physiology ,Cell Proliferation ,Transplantation ,medicine.diagnostic_test ,Reverse Transcriptase Polymerase Chain Reaction ,lcsh:R ,Human embryonic stem cells (hESCs) ,Cell Biology ,Cell sorting ,Dimethyl sulfoxide free ,Flow Cytometry ,equipment and supplies ,Polyampholytes ,Propylene Glycol ,Vitrification ,Embryonic stem cell ,Molecular biology ,030104 developmental biology ,Cell culture ,Karyotyping ,embryonic structures ,Alkaline phosphatase ,biological phenomena, cell phenomena, and immunity - Abstract
Safe and stable cryopreservation is critical for research involving human embryonic stem cells (hESCs). Dimethyl sulfoxide (DMSO) is a popular cryoprotective agent; however, its cytotoxicity cannot be ignored. Thus, there is a need for an alternate cryoprotectant. We reported previously that a novel cryopreservation reagent, StemCell Keep™ (SCK), was effective for cryopreserving human induced pluripotent stem cells (hiPSCs) by vitrification. Because hESCs and hiPSCs are not identical, the current study examined the use of SCK on hESCs. hESCs cryopreserved with SCK were thawed and cultured on SNL 76/7 cells, which were derived from a mouse fibroblast STO cell line transformed with neomycin resistance and murine LIF genes. After cryopreservation, cultured hESCs were assessed for their attachment ability and characterized by alkaline phosphatase (AP) and immunocytochemical (ICC) staining, fluorescence-activated cell sorting (FACS), reverse transcription polymerase chain reaction (RT-PCR), and karyotyping. The proliferation of SCK-cryopreserved hESCs cultured on SNL cells, or in feeder-free conditions, was higher than that of cells preserved in a solution of 2 M DMSO, 1 M acetamide, and 3 M propylene glycol (DAP). The cell number with SCK-cryopreserved hESCs was about twice that of hESCs cryopreserved in DAP. The pluripotency of SCK-cryopreserved hESCs was similar to that of DAP-cryopreserved hESCs based on AP staining. Data from ICC, FACS, and RT-PCR analyses showed that stem cell markers were continually expressed on SCK-cryopreserved hESCs. The teratoma assay showed that SCK-cryopreserved hESCs differentiated into three germ layers. Furthermore, SCK-cryopreserved hESCs had normal karyotypes. These data indicate that SCK was effective for cryopreservation of hESCs by vitrification.
- Published
- 2017
17. Hypothermicpreservation of Mouse Induced Pluripotent Stem Cells by Polyampholytes
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Kazuaki Matsumura, Suong-Hyu Hyon, and Hak Hee Kim
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Chemistry ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Induced pluripotent stem cell ,Biotechnology ,Cell biology - Published
- 2014
18. Hydrogelation of dextran-based polyampholytes with cryoprotective properties via click chemistry
- Author
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Robin Rajan, Minkle Jain, Kazuaki Matsumura, and Suong-Hyu Hyon
- Subjects
Cryopreservation ,Biocompatibility ,Cryoprotectant ,Biomedical Engineering ,complex mixtures ,chemistry.chemical_compound ,Hydrogel ,Dextran ,chemistry ,Tissue engineering ,Polymer chemistry ,Self-healing hydrogels ,Click chemistry ,Biophysics ,General Materials Science ,Cell encapsulation ,Injectable hydrogel - Abstract
Hydrogels are promising substrates for tissue engineering applications because of their unique biocompatibility, flexible methods of synthesis, range of constituents, and desirable physical characteristics. Cryopreservation of cell-containing constructs using such hydrogel scaffolds is in high demand in tissue-engineering applications for the production of “off-the-shelf” tissue-engineered products. However, cryopreservation of regenerated tissues including cell sheets and cell constructs is not easy compared to the preservation of cell suspensions, even when cryoprotectants are used. Here, we report a dextran-based polyampholyte hydrogel that itself shows cryoprotective properties, which could be useful for cell encapsulation and tissue engineering applications involving hydrogel formation. Amination was performed by introducing poly-L-lysine onto azide groups conjugated with dextran, and a portion of the amino groups was converted into carboxyl groups. These dextran-based polyampholytes showed good cryoprotective properties for mammalian cells, and the addition of dextran substituted with dibenzylcyclooctyne acid induced in situ hydrogel formation via Cu-free click chemistry with high biocompatibility. Cells encapsulated with such in situ hydrogels can be cryopreserved well without the addition of any cryoprotectants. Thus, these hydrogels can serve as scaffolds with cryoprotective properties that also provide structural integrity to tissue constructs.
- Published
- 2013
19. Low cytotoxic tissue adhesive based on oxidized dextran and epsilon-poly-<scp>l</scp>-lysine
- Author
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Hajime Sugai, Suong-Hyu Hyon, Kazuaki Matsumura, and Naoki Nakajima
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chemistry.chemical_classification ,food.ingredient ,Metals and Alloys ,Biomedical Engineering ,Periodate ,Aldehyde ,Gelatin ,Allylamine ,Biomaterials ,Acylation ,chemistry.chemical_compound ,Dextran ,food ,chemistry ,Polymer chemistry ,Ceramics and Composites ,Amine gas treating ,Glutaraldehyde - Abstract
A novel adhesive hydrogel consisting of dextran and epsilon-poly(L-lysine) (dextran-PL) with multiple biomedical applications was developed. Periodate oxidation in aqueous media almost stoichiometrically introduces aldehyde groups in dextran molecules, and aldehyde dextran can react with the primary amino groups in epsilon-PL (ɛ-PL) at neutral pH to form a hydrogel. The gelation time of the hydrogel can be easily controlled by the extent of oxidation in dextran and of the acylation in ɛ-PL by anhydrides. The shear adhesion strength of dextran-PL was 10 times higher than that of fibrin glue, when wet collagen sheets were selected as test specimens. The cytotoxicity of aldehyde dextran and ɛ-PL were 1000 times lower than that of glutaraldehyde and poly(allylamine). The considerably low cytotoxicity of aldehyde dextran could be ascribed to its low reactivity with amine species when compared with glutaraldehyde. In contrast, a high reactivity of amino groups in ɛ-PL was observed when compared with glycine, L-lysine, and gelatin, which could be explained by their poor dissociation at neutral pH, thus leading to low cytotoxicity.
- Published
- 2013
20. Cryoprotective properties of completely synthetic polyampholytes via reversible addition-fragmentation chain transfer (RAFT) polymerization and the effects of hydrophobicity
- Author
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Kazuaki Matsumura, Minkle Jain, and Robin Rajan
- Subjects
Materials science ,Cryoprotectant ,Cell Survival ,Polymers ,Biomedical Engineering ,Biophysics ,Bioengineering ,cryopreservation ,polyampholyte ,Cell Line ,Biomaterials ,Mice ,chemistry.chemical_compound ,biocompatibility ,Cryoprotective Agents ,Polymer chemistry ,Cryoprotective Agent ,Animals ,Reversible addition−fragmentation chain-transfer polymerization ,chemistry.chemical_classification ,RAFT polymerization ,Cationic polymerization ,Chain transfer ,Polymer ,Monomer ,chemistry ,Polymerization ,Methacrylates ,Hydrophobic and Hydrophilic Interactions - Abstract
A completely synthetic polyampholyte cryoprotectant was developed with cationic and anionic monomers by reversible addition-fragmentation chain transfer polymerization. The neutralized random polyampholyte, which had an equal composition ratio of monomers, showed high cryoprotective properties in mammalian cells. Introduction of a small amount of hydrophobic monomer enhanced cell viability after cryopreservation, indicating the importance of hydrophobicity. Leakage experiments confirmed that these polyampholytes protected the cell membrane during cryopreservation. Due to low cytotoxicity, this polyampholyte has the potential to replace the convention cryoprotective agent dimethyl sulfoxide. The present study is the first to show that we can design a polymeric cryoprotectant that will protect the cell membrane during freezing using appropriate polymerization techniques.
- Published
- 2013
21. Long-term cryopreservation of human mesenchymal stem cells using carboxylated poly-l-lysine without the addition of proteins or dimethyl sulfoxide
- Author
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Suong-Hyu Hyon, Kazuaki Matsumura, Fumiaki Hayashi, and Toshio Nagashima
- Subjects
Succinic Anhydrides ,Materials science ,Cell Survival ,Cellular differentiation ,Biomedical Engineering ,Biophysics ,Bioengineering ,Osteocytes ,Regenerative medicine ,Cryopreservation ,Biomaterials ,chemistry.chemical_compound ,Cryoprotective Agents ,Tissue engineering ,polyampholytes ,stem cells ,Humans ,Polylysine ,Viability assay ,Cell Proliferation ,Cell growth ,Dimethyl sulfoxide ,Mesenchymal stem cell ,Cell Differentiation ,Mesenchymal Stem Cells ,Cell biology ,Biochemistry ,chemistry ,tissue engineering - Abstract
Human bone marrow-derived mesenchymal stem cells (hBMSCs) are known for their potential to undergo mesodermal differentiation into many cell types, including osteocytes, adipocytes, and chondrocytes. Therefore, hBMSCs could be used for a variety of regenerative medicine therapies; in fact, hBMC-derived osteocytes have already been used in bone reconstruction. This study discusses the viability and the differentiation properties of hBMSCs that have been cryopreserved in the absence of proteins or dimethyl sulfoxide (DMSO), by using a novel polyampholyte cryoprotectant (CPA). This CPA is based on carboxylated poly-L-lysine (COOH-PLL) and was prepared by a reaction between -poly-L-lysine and succinic anhydride. 1H-NMR and two-dimensional correlation (1H-13C HSQC) spectroscopy revealed that COOH-PLL did not have a special structure in solution. hBMSCs can be cryopreserved for 24 months at −80°C by using a 7.5% (w/w) cryopreserving solution of COOH-PLL which introduces carboxyl groups that result in >90% cell viability after thawing. Furthermore, the cryopreserved hBMSCs fully retained both their proliferative capacity as well as their potential for osteogenic, adipogenic, and chondrogenic differentiation. Confocal laser-scanning microscopy findings showed that the polyampholyte CPA did not penetrate the cell membrane; rather, it attached to the membrane during cryopreservation. These results indicate that the cryoprotective mechanisms of COOH-PLL might differ from those of currently used small-molecule CPAs. These results also suggest that using COOH-PLL as a cryoprotectant for hBMSC preservation can eliminate the use of proteins and DMSO, which would be safer if these cells were used for cell transplantation or regenerative medicine.
- Published
- 2013
22. Thixotropic injectable hydrogel using a polyampholyte and nanosilicate prepared directly after cryopreservation
- Author
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Kazuaki Matsumura and Minkle Jain
- Subjects
Thixotropy ,Materials science ,Cell Survival ,Static Electricity ,injectable hydrogel ,Bioengineering ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Regenerative medicine ,polyampholyte ,Cryopreservation ,thixotropy ,Hydrogel, Polyethylene Glycol Dimethacrylate ,Cell Line ,Injections ,Nanocomposites ,Biomaterials ,Mice ,Tissue engineering ,X-Ray Diffraction ,Elastic Modulus ,Cryoprotective Agent ,Spectroscopy, Fourier Transform Infrared ,Cell Adhesion ,Animals ,Polylysine ,Cell survival ,Cell Proliferation ,Nanocomposite ,nanocomposite ,Silicates ,food and beverages ,Succinates ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Mechanics of Materials ,Self-healing hydrogels ,Nanoparticles ,0210 nano-technology ,Biomedical engineering - Abstract
Success of tissue engineering applications in regenerative medicine requires the preservation of tissue-engineered products at a low temperature. This can be successfully achieved by the use of cryoprotective agent (CPA). In this study, we formulated a unique injectable hydrogel for the purpose of cell delivery after cryopreservation by using polyampholyte CPA. The polyampholyte showed excellent post-thaw cell survival, and after thawing, the polymeric CPA did not have to be removed because of its low cytotoxicity. The polyampholyte could be transformed into a hydrogel by mixing with nanosilicates. Previously, nanosilicates were used to improve mechanical properties, but this is the first report of the use of a nanosilicate together with CPA to formulate hydrogels. Inclusion of the nanosilicate led to the formation of thixotropic hydrogels, which can be injected using fine needles. These gels with tunable mechanical properties can be injected into defect sites to form scaffolds for cell growth and tissue repair, and they do not require any separate seeding of cells before injection, thus eliminating the need for cell harvesting and cell maintenance. This is a distinct system in which cells can be cryopreserved until before usage; when required, the cells in the polyampholyte can be revived to their original state and the thixotropic hydrogel can be formed. The combination of thixotropy and cytocompatibility of the gels could enable a wide range of biomedical applications such as cell delivery and orthopedic repair.
- Published
- 2016
23. Cell encapsulation and cryostorage in PVA-gelatin cryogels: incorporation of carboxylated ε-poly-L-lysine as cryoprotectant
- Author
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Clement L. Higginbotham, Suong-Hyu Hyon, John G. Lyons, Kazuaki Matsumura, Paul A. Cahill, Nihal Engin Vrana, Luke M. Geever, James E. Kennedy, and Garrett B. McGuinness
- Subjects
Scaffold ,food.ingredient ,Cryoprotectant ,Cell Survival ,Myocytes, Smooth Muscle ,Biomedical Engineering ,Medicine (miscellaneous) ,Gelatin ,Polyvinyl alcohol ,Biomaterials ,chemistry.chemical_compound ,Cryoprotective Agents ,food ,In vivo ,Tensile Strength ,Materials Testing ,Animals ,Polylysine ,Cell encapsulation ,Cytotoxicity ,Cell Proliferation ,Cryopreservation ,Calorimetry, Differential Scanning ,Chemistry ,Endothelial Cells ,Cells, Immobilized ,Coculture Techniques ,Biomechanical Phenomena ,Endothelial stem cell ,Polyvinyl Alcohol ,Biophysics ,Cattle ,Stress, Mechanical ,Cryogels ,Biomedical engineering - Abstract
It is desirable to produce cryopreservable cell-laden tissue-engineering scaffolds whose final properties can be adjusted during the thawing process immediately prior to use. Polyvinyl alcohol (PVA)-based solutions provide platforms in which cryoprotected cell suspensions can be turned into a ready-to-use, cell-laden scaffold by a process of cryogelation. In this study, such a PVA system, with DMSO as the cryoprotectant, was successfully developed. Vascular smooth muscle cell (vSMC)-encapsulated cryogels were investigated under conditions of cyclic strain and in co-culture with vascular endothelial cells to mimic the environment these cells experience in vivo in a vascular tissue-engineering setting. In view of the cytotoxicity DMSO imposes with respect to the production procedure, carboxylated poly-L-lysine (COOH-PLL) was substituted as a non-cytotoxic cryoprotectant to allow longer, slower thawing periods to generate more stable cryogels. Encapsulated vSMC with DMSO as a cryoprotectant responded to 10% cyclic strain with increased alignment and proliferation. Cells were stored frozen for 1 month without loss of viability compared to immediate thawing. SMC-encapsulated cryogels also successfully supported functional endothelial cell co-culture. Substitution of COOH-PLL in place of DMSO resulted in a significant increase in cell viability in encapsulated cryogels for a range of thawing periods. We conclude that incorporation of COOH-PLL during cryogelation preserved cell functionality while retaining fundamental cryogel physical properties, thereby making it a promising platform for tissue-engineering scaffolds, particularly for vascular tissue engineering, or cell preservation within microgels.
- Published
- 2011
24. Preservation of Platelets by Adding Epigallocatechin-3-O-Gallate to Platelet Concentrates
- Author
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Mitsuru Kurihara, Jung Yoon Bae, Sadami Tsutsumi, Hiroshi Takayama, Kazuaki Matsumura, and Suong-Hyu Hyon
- Subjects
Blood Platelets ,Biomedical Engineering ,lcsh:Medicine ,Apoptosis ,Epigallocatechin gallate ,Pharmacology ,complex mixtures ,Antioxidants ,Catechin ,Thromboplastin ,chemistry.chemical_compound ,Platelet preservation ,Prothrombinase ,Blood plasma ,Humans ,heterocyclic compounds ,Platelet ,Platelet activation ,Chemokine CCL5 ,Gelsolin ,Transplantation ,L-Lactate Dehydrogenase ,Caspase 3 ,Chemistry ,lcsh:R ,food and beverages ,Cell Biology ,P-Selectin ,Biochemistry ,Blood Preservation ,sense organs - Abstract
The effect of epigallocatechin-3- O-gallate (EGCG), a major component of green tea, on platelet preservation was evaluated. Single donor platelets ( N = 10) were collected and preserved by the standard method. EGCG was added to the platelet concentrates before preservation and then the functional and biochemical parameters were monitored throughout the storage period. After 6 days of preservation, the aggregability of the platelets was significantly maintained by addition of 50 and 100 μg/ml of EGCG. Platelet prothrombinase activity was also significantly retained by the addition of EGCG. The accumulation of P-selectin and RANTES in the plasma preserved with EGCG was less than those preserved without EGCG, which indicated that EGCG might inhibit platelet activation. Furthermore, EGCG reduced the increase of LDH in plasma during preservation and inhibited the activation of caspase-3 and cleavage of gelsolin, thereby showing that EGCG could inhibit the apoptosis of platelets. These results suggest that EGCG may play an effective role in preserving platelets by inhibiting the activation and apoptosis of platelets.
- Published
- 2009
25. Tea Polyphenol Inhibits Allostimulation in Mixed Lymphocyte Culture
- Author
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Hirofumi Noguchi, Tatsuo Kina, Suong-Hyu Hyon, Kazuaki Matsumura, Yasuhiro Iwanaga, and Jong-yoon Kim
- Subjects
0301 basic medicine ,Green Tea Polyphenols ,Biomedical Engineering ,lcsh:Medicine ,Apoptosis ,Pharmacology ,Lymphocyte Activation ,complex mixtures ,Catechin ,Mice ,03 medical and health sciences ,Phenols ,Animals ,Allorecognition ,Cells, Cultured ,Cell Proliferation ,Immunosuppressive effect ,Flavonoids ,Mice, Inbred BALB C ,Transplantation ,Tea ,030102 biochemistry & molecular biology ,Plant Extracts ,Chemistry ,lcsh:R ,Polyphenols ,food and beverages ,Cell Biology ,Flow Cytometry ,Mice, Inbred C57BL ,030104 developmental biology ,Polyphenol ,Interleukin-2 ,Female ,Lymphocyte Culture Test, Mixed ,Immunosuppressive Agents ,Mixed lymphocyte culture - Abstract
Green tea polyphenols are known to protect allogenic donor tissues from acute rejection by their recipients. This immunosuppressive effect may be generated by a unique chemical property of the major component, epigallocatechin-o-gallate (EGCG), which can block specific cell surface molecules of the donor tissues. To test this hypothesis, we examined the effects of EGCG on the murine mixed lymphocyte reactions. EGCG treatment of stimulator cells significantly attenuated the proliferation of responder T cells. The proliferation did not recover upon the secondary stimulations by fresh untreated cells or exogenous IL-2. Flow cytometric analyses showed that EGCG treatment decreased the staining intensities of various cell surface molecules including MHC II, which plays a major role in antigen presentation, and B7.1, B7.2, and their ligand, CD28, which are required for costimulatory signals in T-cell activation. These results suggest that an anergic state of alloreactive T cells may be induced by either weakening of antigen signaling or blockage of costimulatory signals with EGCG. Other possible mechanisms behind the immunosuppressive effect and a potential use of EGCG treatment of donor tissues in transplantation medicine are discussed.
- Published
- 2007
26. A Freeze‐Concentration and Polyampholyte‐Modified Liposome‐Based Antigen‐Delivery System for Effective Immunotherapy
- Author
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Kazuaki Matsumura, Sana Ahmed, and Satoshi Fujita
- Subjects
0301 basic medicine ,liposomes ,medicine.medical_treatment ,Biomedical Engineering ,Pharmaceutical Science ,02 engineering and technology ,Major histocompatibility complex ,polyampholyte ,Biomaterials ,03 medical and health sciences ,Mice ,Antigen ,Freezing ,medicine ,Animals ,Antigens ,Liposome ,freeze-concentration ,biology ,Antigen delivery ,Immunotherapy ,021001 nanoscience & nanotechnology ,Molecular biology ,Cancer treatment ,Cell biology ,Cytosol ,Ovalbumin ,030104 developmental biology ,RAW 264.7 Cells ,biology.protein ,Cytokines ,immunotherapy ,0210 nano-technology - Abstract
Immunotherapy is an exciting new approach in cancer treatment. Here, we describe the development of a novel freeze-concentration method that could be applicable in immunotherapy. The method involves freezing cells in the presence of pH-sensitive, polyampholyte-modified liposomes with encapsulated ovalbumin (OVA) as the antigen. In RAW 264.7 cells, compared to the non-frozen condition, freeze-concentration of polyampholyte-modified liposomes encapsulating OVA resulted in efficient OVA uptake and also allowed for its delivery to the cytosol. Efficient delivery of OVA to the cytosol was shown to be partly due to the pH-dependence of the polyampholyte-modified liposomes. Cytosolic OVA delivery also resulted in significant up-regulation of the major histocompatibility complex class I pathway through a process known as cross-stimulation, as well as an increase in the release of IL-1β, IL-6, and TNF-α. Our results demonstrate that the combination of a simple freeze-concentration method and polyampholyte-modified liposomes might be useful in future immunotherapy applications.
- Published
- 2017
27. Surface modification of poly(ethylene-co-vinyl alcohol) (EVA). Part I. Introduction of carboxyl groups and immobilization of collagen
- Author
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Chunyan Peng, Naoki Nakajima, Sadami Tsutsumi, Suong-Hyu Hyon, and Kazuaki Matsumura
- Subjects
Titanium ,Vinyl alcohol ,Materials science ,Biocompatibility ,Surface Properties ,Biomedical Engineering ,Biocompatible Materials ,Polyethylene ,Biomaterials ,chemistry.chemical_compound ,Ozone ,Polymerization ,chemistry ,Polymer chemistry ,Surface modification ,Polyvinyls ,Collagen ,Ethylene glycol ,Type I collagen ,Protein Binding ,Acrylic acid - Abstract
To enhance the surface biocompatibility of poly(ethylene-co-vinyl alcohol) (EVA) and high-density polyethylene (HDPE), carboxyl groups were introduced by ozone exposure. Type I collagen was immobilized onto the surface through polyion complexing. The carboxyl groups on the EVA were characterized by electron spectroscopy for chemical analysis and neutralization. The amounts of the carboxylic group and collagen increased with increases in time and temperature of exposure. Water-soluble fragments were produced by ozone exposure to EVA, and they acted as collagen crosslinkers. The differences in charge distribution of carboxyl groups affected the amount of collagen immobilization. Graft polymerization of acrylic acid was also carried out onto EVA and HDPE surfaces. The amount of collagen immobilized by graft polymerization was much higher than that by ozone exposure despite the introduction of almost the same amounts of carboxylic groups. It was suggested that the negative charge distribution influences the amount of collagen immobilized onto films.
- Published
- 2000
28. Morphologic study and syntheses of type I collagen and fibronectin of human periodontal ligament cells cultured on poly(ethylene-co-vinyl alcohol) (EVA) with collagen immobilization
- Author
-
Suong-Hyu Hyon, Naoki Nakajima, Sadami Tsutsumi, Kazuaki Matsumura, and Chunyan Peng
- Subjects
Materials science ,Periodontal Ligament ,Cell Culture Techniques ,Biomedical Engineering ,Biomaterials ,stomatognathic system ,otorhinolaryngologic diseases ,Humans ,Periodontal fiber ,Cell adhesion ,Cells, Cultured ,Dental Implants ,biology ,Regeneration (biology) ,Adhesion ,Molecular biology ,In vitro ,Fibronectins ,Fibronectin ,Kinetics ,Cell culture ,biology.protein ,Polyvinyls ,Collagen ,sense organs ,Cell Division ,Type I collagen ,Biomedical engineering - Abstract
The purpose of this study was to regenerate the human periodontal ligament (PDL) around dental implants by using a hybrid structure of cells with materials, such as PDL cells + collagen + poly(ethylene-co-vinyl alcohol) (EVA) on titanium implant. Human PDL cells were cultured on the EVA surface coated with type I collagen and the cell adhesion and extension were investigated. Furthermore, collagen type I and fibronectin syntheses were analyzed. The serum free culture was also tried, to investigate the role of collagen in detail. The results showed that: 1. Satisfactory adhesion, extension, and proliferation of the PDL cells on the EVA films coated with collagen were observed, but were not good without collagen. 2. Immunostaining of cultured PDL cells revealed the syntheses of type I collagen, when cultured on the EVA coated with collagen or conventional culture dish, though fibronectin synthesis was observed even in the EVA without collagen. 3. Only PDL cells on the EVA coated with collagen proliferated well in the absence of serum. These results indicate that our novel implant material (EVA coated with collagen) provides a possibility of PDL regeneration on dental implants.
- Published
- 2000
29. Type I atelocollagen grafting onto ozone-treated polyurethane films: Cell attachment, proliferation, and collagen synthesis
- Author
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Ki Dong Park, Hwal Suh, Yu Shik Hwang, Jong Chul Park, Jong Eun Lee, Kazuaki Matsumura, and Suong-Hyu Hyon
- Subjects
chemistry.chemical_classification ,Materials science ,Iodide ,Biomedical Engineering ,Matrix (biology) ,Grafting ,Peroxide ,Biomaterials ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Polymerization ,Chemical engineering ,Polymer chemistry ,Copolymer ,medicine ,Fibroblast ,Polyurethane - Abstract
An approach is presented for the graft copolymerization of type I atelocollagen onto the surface of polyurethane (PU) films treated with ozone. Through inducing oxidization to modify PU surface by ozone, peroxide groups are easily generated on the surface. Those peroxides are broken by redox-polymerization, and provide active species which initiate graft polymerization by reacting with amines in the collagen molecules. The ozone oxidation time and voltage could readily control the amount of peroxide production. The surface density of generated peroxides on PU surface was determined by iodide method. The maximum concentration of peroxide was about 10.20 × 10−8mol/cm2 when ozone oxidation was performed at 60 V for 30 min. After the reaction of PU by ozone oxidation, type I atelocollagen was graft-copolymerized onto the PU film. All the physical measurements on the collagen-grafted surface indicated that the PU surface was effectively covered with type I atelocollagen. The interaction of the collagen-grafted PU surface with fibroblasts could be greatly enhanced by the surface graft polymerization with type I atelocollagen. Attachment and proliferation of fibroblasts on the grafted type I atelocollagen were significantly enhanced, and it is assumed that the atelocollagen matrix supported the initial attachment and growth of cells. In the early stage of proliferation, collagen synthesis in fibroblasts was not activated and remained at a relatively low level due to the grafted type I atelocollagen, increasing only with fibroblast differentiation. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 52, 669–677, 2000.
- Published
- 2000
30. Development of Artificial Intra-articular Polyethylene Glycol (PEG) Lubricant for Survival of Total Knee Joint Patient (Preliminary Study for Clinical Application)
- Author
-
Yoshiyuki Honda, Suong-Hyu Hyon, Naoki Nakajima, Masanori Kobayashi, and Kazuaki Matsumura
- Subjects
chemistry.chemical_classification ,Materials science ,Scanning electron microscope ,technology, industry, and agriculture ,Polyethylene glycol ,Polymer ,Tribology ,Polyethylene ,chemistry.chemical_compound ,Lubricity ,chemistry ,PEG ratio ,Lubricant ,Biomedical engineering - Abstract
We have developed polyethylene glycol (PEG) with excellent tribology as artificial joint lubricity agent for reducing the wear of UHMWPE. PEG of molecular weight two million was used. And the PEG lubricity agent samples prepared a kinds of 3wt% in this study. We performed mechanical experiment and observation of wear surface. The mechanical experiment for wear test on ultra-high molecular weight polyethylene (UHMWPE) and Co-Cr alloy of artificial joint : a control group and PEG group. The human symovial fluid and hyaluronic acid were prepared for the control group. The wear surface observation of UHMWPE was performed by scanning electron microscope (SEM). The mechanical experiment results suggested that the wear of control group less volume than that of PEG group. The SEM pictures showed the wear of control group progressing than that of PEG group. These results showed that PEG lubricant might be effective as an artificial lubricant in joint.
- Published
- 2011
31. In Vivo Cancer Targeting of Water-Soluble Taxol by Folic Acid Immobilization
- Author
-
Naoki Nakajima, Suong-Hyu Hyon, Junichi Nakamura, and Kazuaki Matsumura
- Subjects
Materials science ,business.industry ,medicine.medical_treatment ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Cancer targeting ,Pharmacology ,In vitro ,Biotechnology ,chemistry.chemical_compound ,Dextran ,Folic acid ,chemistry ,Paclitaxel ,In vivo ,polycyclic compounds ,medicine ,business ,Saline ,Survival rate ,hormones, hormone substitutes, and hormone antagonists - Abstract
Previously, folic acid receptor-targeted Dextran-Taxol-Folic acid (Dex-TXL-FA) has shown the in vitro superior and selective antitumor activity against human oral cancer cell line (KB) compared with the absent of folic acid, Dextran- Taxol. Present study is given for further investigation of in vivo antitumor efficacy of Dex-TXL-FA in the murine tumor xenograft model. To evaluate the antitumor effect of taxol, tumor bearing mice were prepared by s.c. inoculation of 1.0 × 10 6 KB cells in the back of nude mice. Seven days after inoculation, the administration of saline, paclitaxel for injection (PTX), Dex-TXL, FA-adsorbed Dex-TXL and Dex-TXL-FA (covalent) was started at a dose of 10mg/kg, by i.v. injection via the lateral tail vein three times ( on day 7, 9, and 11) and animal survival rate and tumor sizes were monitored.FA- adsorbed Dex-TXL and Dex-TXL-FA (covalent) showed approximately 3 times greater anticancer effect than that of taxol at the 30th day after tumor implantation. Furthermore, these FA immobilized TXL showed 2-3 month longer animal survival than that of taxol. These results suggest the conjugation with Dex and FA could provide an improvement in the anticancer therapy of taxol.
- Published
- 2011
32. Polyampholytes as Cryoprotective Agents for Mammalian Cell Cryopreservation
- Author
-
Kazuaki Matsumura, Jung Yoon Bae, and Suong-Hyu Hyon
- Subjects
Cell Survival ,Biomedical Engineering ,lcsh:Medicine ,Buffers ,Cryopreservation ,Cell Line ,chemistry.chemical_compound ,Cryoprotective Agents ,Cryoprotective Agent ,Glycerol ,Animals ,Humans ,Cytotoxicity ,Mammals ,Transplantation ,Chemistry ,Dimethyl sulfoxide ,Ice ,lcsh:R ,Succinic anhydride ,Cell Differentiation ,Mesenchymal Stem Cells ,Cell Biology ,Rats ,Biochemistry ,Cell culture ,Crystallization ,Ethylene glycol - Abstract
Cryoprotective agents (CPAs) such as dimethyl sulfoxide (DMSO), glycerol, ethylene glycol, and propylene glycol have been used for the cryopreservation of cells and tissues. DMSO is the most effective CPA but shows high cytotoxicity and can effect differentiation. ∈-Poly-l-lysine (PLL) derivatives show higher cryopreservation efficiency than the conventional CPAs. Culture medium solutions with 7.5 w/w% of PLL whose amino groups of more than 50 mol% were converted to carboxyl groups by succinic anhydride showed higher postthaw survival efficiency of L929 cells than those of current CPAs without the addition of any proteins. In addition, rat mesenchymal stem cells were cryopreserved more effectively than with DMSO and fully retained the potential for proliferation and differentiation. Furthermore, many kinds of cells could be cryopreserved with PLL having the appropriate ratio of COOH groups, regardless of the cell types, including adhesive and floating cells, human- and mouse-derived cells, primary cells, and established cell lines. The properties might be associated with the antifreeze protein properties. These results indicate that these polymeric extracellular CPAs may replace current CPAs and the high viability after thawing and nonnecessity of serum ensure that these CPAs may be used in various preservation fields.
- Published
- 2010
33. Effects of epigallocatechin gallate on osteogenic capability of human mesenchymal stem cells after suspension in phosphate-buffered saline
- Author
-
Mika Tadokoro, Shinichi Yoshiya, Noriko Kotobuki, Kazuaki Matsumura, Kaori Kashiwa, Hajime Ohgushi, and Suong-Hyu Hyon
- Subjects
Adult ,Male ,Cell Survival ,medicine.medical_treatment ,Biomedical Engineering ,Bioengineering ,Epigallocatechin gallate ,Buffers ,Sodium Chloride ,Biochemistry ,Antioxidants ,Catechin ,Suspension (chemistry) ,Phosphates ,Biomaterials ,chemistry.chemical_compound ,Osteogenesis ,medicine ,Humans ,Saline ,Cells, Cultured ,Cell Proliferation ,Chemistry ,Regeneration (biology) ,Mesenchymal stem cell ,Phosphate buffered saline ,Cell Differentiation ,Mesenchymal Stem Cells ,Green tea ,Cell biology ,Female ,Biomedical engineering - Abstract
Administration of culture-expanded mesenchymal stem cells (MSCs) has been sought for regeneration of various damaged tissues/organs in clinical situations. Liquid suspensions of MSCs have either been directly injected into organs or generally infused. In this study, we focused on the viability and differentiation of MSCs after suspension in phosphate-buffered saline. When the MSCs were treated with epigallocatechin gallate, which is purified from green tea catechin, the MSCs showed high viability as well as osteogenic differentiation capability even while suspended in phosphate-buffered saline for 4 days at 4 degrees C. In contrast, nontreated MSCs showed low viability and showed hardly any differentiation. The rate of proliferation of the treated MSCs was much higher than that of the nontreated MSCs. These results indicate the usefulness of epigallocatechin gallate treatment for fabrication of ready-to-use cellular products of MSC suspension.
- Published
- 2009
34. Long-Term Preservation of Rat Skin Tissue by Epigallocatechin-3--Gallate
- Author
-
Takeshi Kawazoe, Suong-Hyu Hyon, Hak Hee Kim, Shigehiko Suzuki, and Kazuaki Matsumura
- Subjects
Male ,Antioxidant ,Time Factors ,medicine.medical_treatment ,Biomedical Engineering ,Mice, Nude ,lcsh:Medicine ,Epigallocatechin gallate ,Biology ,Pharmacology ,Carbohydrate metabolism ,complex mixtures ,Cryopreservation ,Antioxidants ,Catechin ,Green fluorescent protein ,chemistry.chemical_compound ,Mice ,Biopsy ,medicine ,Animals ,heterocyclic compounds ,Gallic acid ,Skin ,Transplantation ,medicine.diagnostic_test ,integumentary system ,lcsh:R ,food and beverages ,Cell Biology ,Skin Transplantation ,Rats ,Glucose ,chemistry ,Biochemistry ,Polyphenol ,Tissue Preservation ,sense organs - Abstract
Skin grafts can be preserved by cryopreservation and refrigerated storage at 4 degrees C. Epigallocatechin-3-O-gallate (EGCG) enhances the viability of stored skin grafts and also extends the storage time up to 7 weeks at 4 degrees C. EGCG, the major polyphenolic constituent present in green tea, has potent antioxidant, antimicrobial, antiproliferative, and free radical scavenging effects. This study examined the effects of EGCG on skin cryopreservation. Skin sample biopsy specimens from GFP rats were previously treated with/without EGCG then moved to -196 degrees C. Skin samples were transplanted to nude mice after 2, 8, and 24 weeks of preservation. Glucose consumption was measured after thawing to assess the metabolic activity. Two weeks later the transplanted skin grafts were excised and histologically analyzed. Histological examinations revealed the degeneration of the epidermal and dermal layers in all groups. In the EGCG groups, the grafts showed higher integrity in the epidermal layer and dermal matrix. The present findings suggest the future clinical usefulness of EGCG for skin preservation; however, the mechanism by which EGCG promotes skin preservation still remains unclear.
- Published
- 2009
35. Beneficial Storage Effects of Epigallocatechin-3--Gallate on the Articular Cartilage of Rabbit Osteochondral Allografts
- Author
-
Suong-Hyu Hyon, Jung Yoon Bae, Sadami Tsutsumi, Amu Kawaguchi, Shigeyuki Wakitani, and Kazuaki Matsumura
- Subjects
Cartilage, Articular ,medicine.medical_specialty ,Time Factors ,Biomedical Engineering ,Cold storage ,lcsh:Medicine ,Epigallocatechin gallate ,Antioxidants ,Catechin ,Glycosaminoglycan ,Andrology ,Extracellular matrix ,chemistry.chemical_compound ,medicine ,Cytotoxic T cell ,Animals ,Transplantation, Homologous ,Glycosaminoglycans ,Transplantation ,Hyaline cartilage ,Cartilage ,lcsh:R ,food and beverages ,Cell Biology ,Surgery ,medicine.anatomical_structure ,Hyaline Cartilage ,chemistry ,Cancer cell ,Rabbits ,Tissue Preservation - Abstract
A fresh osteochondral allograft is one of the most effective treatments for cartilage defects of the knee. Despite the clinical success, fresh osteochondral allografts have great limitations in relation to the short storage time that cartilage tissues can be well-preserved. Fresh osteochondral grafts are generally stored in culture medium at 4°C. While the viability of articular cartilage stored in culture medium is significantly diminished within 1 week, appropriate serology testing to minimize the chances for the disease transmission requires a minimum of 2 weeks. (–)-Epigallocatechin-3- O-gallate (EGCG) has differential effects on the proliferation of cancer and normal cells, thus a cytotoxic effect on various cancer cells, but a cytopreservative effect on normal cells. Therefore, a storage solution containing EGCG might extend the storage duration of articular cartilages. Rabbit osteochondral allografts were performed with osteochondral grafts stored at 4°C in culture medium containing EGCG for 2 weeks and then the clinical effects were examined with macroscopic and histological assessment after 4 weeks. The cartilaginous structure of an osteochondral graft stored with EGCG was well-preserved with high cell viability and glycosaminoglycan (GAG) content of the extracellular matrix (ECM). After an osteochondral allograft, the implanted osteochondral grafts stored with EGCG also provided a significantly better retention of the articular cartilage with viability and metabolic activity. These data suggest that EGCG can be an effective storage agent that allows long-term preservation of articular cartilage under cold storage conditions.
- Published
- 2009
36. Reversible Regulation of Cell Cycle-Related Genes by Epigallocatechin Gallate for Hibernation of Neonatal Human Tarsal Fibroblasts
- Author
-
Kazuaki Matsumura, Jun Kanamune, Suong-Hyu Hyon, Jung Yoon Bae, and Dong-Wook Han
- Subjects
Male ,Cell ,Population ,Biomedical Engineering ,lcsh:Medicine ,Cell Cycle Proteins ,complex mixtures ,Catechin ,medicine ,Humans ,heterocyclic compounds ,education ,Cells, Cultured ,Cell Proliferation ,Oligonucleotide Array Sequence Analysis ,Transplantation ,Cyclin-dependent kinase 1 ,education.field_of_study ,biology ,Cell growth ,Cell Cycle ,Cyclin-dependent kinase 2 ,lcsh:R ,Infant ,food and beverages ,Tarsal Bones ,Cell Biology ,Fibroblasts ,Cell cycle ,Molecular biology ,medicine.anatomical_structure ,Gene Expression Regulation ,biology.protein ,Cell Cycle Profile ,Cyclin-dependent kinase 6 ,sense organs - Abstract
We investigated the hibernation effect of epigallocatechin-3- O-gallate (EGCG) on neonatal human tarsal fibroblasts (nHTFs) by analyzing the expression of cell cycle-related genes. EGCG application to culture media moderately inhibited the growth of nHTFs, and the removal of EGCG from culture media led to complete recovery of cell growth. EGCG resulted in a slight decrease in the cell population of the S and G2/M phases of cell cycle with concomitant increase in that of the G0/G1 phase, but this cell cycle profile was restored to the initial level after EGCG removal. The expression of cyclin D1 (CCND1), CCNE2, CCN-dependent kinase 6 (CDK6), and CDK2 was restored, whereas that of CCNA, CCNB1, and CDK1 was irreversibly attenuated. The expression of a substantial number of genes analyzed by cDNA microarray was affected by EGCG application, and these affected expression levels were restored to the normal levels after EGCG removal. We also found the incorporation of FITC-EGCG into the cytosol of nHTFs and its further nuclear translocation, which might lead to the regulation of the exogenous signals directed to genes for cellular responses including proliferation and cell cycle progression. These results suggest that EGCG temporarily affects not only genes related to the cell cycle but also various other cellular functions.
- Published
- 2009
37. Control of proliferation and differentiation of osteoblasts on apatite-coated poly(vinyl alcohol) hydrogel as an artificial articular cartilage material
- Author
-
Kazuaki Matsumura, Takashi Hayami, Sadami Tsutsumi, and Suong-Hyu Hyon
- Subjects
Cartilage, Articular ,Vinyl alcohol ,Materials science ,Biocompatibility ,Surface Properties ,Osteocalcin ,Biomedical Engineering ,Hydrogel, Polyethylene Glycol Dimethacrylate ,Biomaterials ,chemistry.chemical_compound ,Tissue culture ,Mice ,Dogs ,Coated Materials, Biocompatible ,Implants, Experimental ,Apatites ,Materials Testing ,medicine ,Animals ,Femur ,Cell Proliferation ,Osteoblasts ,integumentary system ,biology ,Cartilage ,Lasers ,Metals and Alloys ,Biomaterial ,Osteoblast ,Cell Differentiation ,3T3 Cells ,Alkaline Phosphatase ,medicine.anatomical_structure ,Durapatite ,chemistry ,Polyvinyl Alcohol ,Ceramics and Composites ,Biophysics ,biology.protein ,Alkaline phosphatase ,Biomedical engineering - Abstract
One of the key challenges in employing biomaterials is determining how to fix them into the surrounding tissue. To enhance the interaction with surrounding bone, amorphous hydroxyapatite (HA) was coated onto the surface of the bio-inert poly(vinyl alcohol) hydrogel (PVA-H), as an artificial cartilage material, by a pulsed laser deposition technique. Next we examined the binding effects of the HA thin film (300 nm thick) to the underlying bone using osteoblast proliferation and differentiation. A mouse osteoblast cell line, MC3T3E1, was cultured on the HA-coated and noncoated PVA-H with a water content of 33% or 53% for 3 weeks. Cell proliferation, alkaline phosphatase (ALP) activity, and levels of osteocalcin were evaluated for biocompatibility and differentiation. HA coating enhanced the cell proliferation, the ALP activity, and the levels of osteocalcin on both low and high water-content PVA-Hs. The cell growth rates on the PVA-H were lower than on tissue culture dishes even after the HA coating was added; however, osteoblastic differentiation was highly promoted by the HA coating on low water content PVA-H. These results suggested that the HA coating on the PVA-H enhanced the affinity between the bone and the PVA-H as an artificial cartilage material in surface replacement arthroplasty.
- Published
- 2009
38. The behavior of vascular smooth muscle cells and platelets onto epigallocatechin gallate-releasing poly(l-lactide-co-epsilon-caprolactone) as stent-coating materials
- Author
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Sadami Tsutsumi, Dong-Wook Han, Kazuaki Matsumura, Han Hee Cho, and Suong-Hyu Hyon
- Subjects
Blood Platelets ,Male ,Materials science ,Vascular smooth muscle ,Chemical Phenomena ,medicine.medical_treatment ,Polyesters ,Myocytes, Smooth Muscle ,Biophysics ,Bioengineering ,Biocompatible Materials ,Epigallocatechin gallate ,complex mixtures ,Polylactic acid ,Catechin ,Muscle, Smooth, Vascular ,Biomaterials ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Restenosis ,Cell Movement ,Spectroscopy, Fourier Transform Infrared ,medicine ,Stent ,Animals ,Platelet ,heterocyclic compounds ,Platelet activation ,Cells, Cultured ,Chemistry, Physical ,food and beverages ,Drug-Eluting Stents ,Adhesion ,Drug release ,medicine.disease ,Platelet Activation ,Controlled release ,Rats ,Polycaprolactone ,chemistry ,Smooth muscle cells ,Mechanics of Materials ,Ceramics and Composites ,Microscopy, Electron, Scanning ,sense organs ,Biomedical engineering - Abstract
Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, thrombosis, inflammation, and restenosis are still major problems for the utility of cardiovascular prostheses such as vascular grafts and stents. Epigallocatechin-3-O-gallate (EGCG), a major polyphenolic constituent of green tea, has been shown to have anti-thrombotic, anti-inflammatory and anti-proliferative activities. It was hypothesized that controlled release of EGCG from biodegradable poly(lactide-co-epsilon-caprolactone, PLCL) stent coatings would suppress migration and invasion of vascular smooth muscle cells (VSMCs) as well as platelet-mediated thrombosis. EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with 5% EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG did, however, EGCG appreciably increase the hydrophilicity of PLCL. EGCG was found to be uniformly dispersed throughout E-PLCL without direct chemical interactions with PLCL. E-PLCL displayed diffusion controlled release of EGCG release for periods up to 34 days. E-PLCL significantly suppressed the migration and invasion of VSMCs as well as the adhesion and activation of platelets. E-PLCL coatings were able to smooth the surface of bare stents with neither cracks nor webbings after balloon expansion. The structural integrity of coatings was sufficient to resist delamination or destruction during 90% dilatation. These results suggest that EGCG-releasing polymers can be effectively applied for fabricating an EGCG-eluting vascular stent to prevent in-stent restenosis and thrombosis.
- Published
- 2007
39. Effects on gingival cells of hydroxyapatite immobilized on poly(ethylene-co-vinyl alcohol)
- Author
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Kazuaki Matsumura, Naoki Nakajima, Suong-Hyu Hyon, and Sadami Tsutsumi
- Subjects
Collagen Type XII ,Periodontium ,Vinyl alcohol ,Materials science ,Osteocalcin ,Biomedical Engineering ,Gingiva ,Biocompatible Materials ,Collagen Type I ,Biomaterials ,Tissue culture ,chemistry.chemical_compound ,Coated Materials, Biocompatible ,Materials Testing ,otorhinolaryngologic diseases ,Periodontal fiber ,Humans ,Regeneration ,Osteonectin ,RNA, Messenger ,Cells, Cultured ,Cell Proliferation ,DNA Primers ,Base Sequence ,Cell growth ,Reverse Transcriptase Polymerase Chain Reaction ,Regeneration (biology) ,Metals and Alloys ,Alkaline Phosphatase ,Molecular biology ,Durapatite ,chemistry ,Ceramics and Composites ,Alkaline phosphatase ,Polyvinyls ,sense organs ,Implant ,Crystallization ,Biomedical engineering - Abstract
Hydroxyapatite was immobilized on poly(ethylene-co-vinyl alcohol) (EVA) by alternate soaking in aqueous CaCl2 and Na2HPO4 solutions, followed by carboxyl groups introduction through ozone exposure in order to investigate the nature of the gingival cells, to control their proliferation and properties and to develop a highly organized hybrid implant possessing periodontium. Human gingival cells were cultured on the ozone-exposed EVA, collagen-immobilized EVA, hydroxyapatite-immobilized EVA, and a conventional tissue culture dish. Cell proliferation was highest on the tissue culture dish and lowest on the hydroxyapatite-immobilized EVA. The results of RT-PCR of gingival cells on hydroxyapatite-immobilized EVA shows that mRNAs expressed in bone and periodontal ligament were determined. Furthermore, alkaline phosphatase activity and ELISA assay revealed that gingival cells acquired the osteoblastic properties when cultured on hydroxyapatite-immobilized EVA, suggesting that the periodontium might be regenerated around implants using gingival cells. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
- Published
- 2007
40. Preservation of Rat Aortic Tissue Transplant with Green Tea Polyphenols
- Author
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Jong-yoon Kim, Dohoon Kim, S.-H. Hyon, Wanxing Cui, Sadami Tsutsumi, and Kazuaki Matsumura
- Subjects
0301 basic medicine ,Preservative ,Cell Survival ,Cell ,Green Tea Polyphenols ,Biomedical Engineering ,lcsh:Medicine ,Pharmacology ,03 medical and health sciences ,0302 clinical medicine ,Phenols ,medicine ,Aortic tissue ,Animals ,Aorta ,Cells, Cultured ,Flavonoids ,Transplantation ,Tea ,Plant Extracts ,Chemistry ,lcsh:R ,Polyphenols ,food and beverages ,Organ Preservation ,Organ Transplantation ,Cell Biology ,Green tea ,Antimicrobial ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,Polyphenol ,030217 neurology & neurosurgery - Abstract
Green tea polyphenols have recently attracted medical attention as bioactive agents with anticancer, antimicrobial, and antiviral effects. We discovered their new usage as preservative agents for tissue transplants. We preserved rat aortas in a DMEM solution containing polyphenols extracted from green tea leaves. The preserved aortas retained original structures and mechanical strength, and were devoid of any undesirable cell secretions for over a month under physiological conditions. In addition, aortas from Lewis rats preserved for a month and transplanted to allogenic ACI rats completely avoided rejection by the host, suggesting that the polyphenols have immunosuppressive actions on the aortic tissues. From these results, we conclude that polyphenol treatment of aortic tissue transplant can maintain its viability for extended periods of time either before or after transplantation, and the method can be applicable to other transplantation situations.
- Published
- 2006
41. Attachment of artificial cartilage to underlying bone
- Author
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Junya Toguchida, Masanori Oka, S. Yura, Suong-Hyu Hyon, Kazuaki Matsumura, Kazuyasu Ushio, Takashi Hayami, and Takashi Nakamura
- Subjects
Artificial bone ,Materials science ,Time Factors ,Composite number ,Biomedical Engineering ,Biocompatible Materials ,Molding (process) ,Bone and Bones ,Biomaterials ,Dogs ,Tissue engineering ,medicine ,Animals ,Composite material ,Titanium ,integumentary system ,Tissue Engineering ,Cartilage ,technology, industry, and agriculture ,Shear resistance ,Prostheses and Implants ,medicine.anatomical_structure ,Titanium fiber ,Polyvinyl Alcohol ,Bone Substitutes ,Polyvinyl alcohol hydrogel ,Biomedical engineering - Abstract
The key problem with artificial joint materials is obtaining quick and firm attachment onto the underlying bone. In developing artificial articular cartilage, composed of polyvinyl alcohol hydrogel (PVA-H), this problem was solved by using a composite osteo-chondral device (COD). This enables attachment within four weeks post-operation by massive bone ingrowth into the pores. The COD consists of PVA-H as an artificial cartilage and titanium fiber mesh (TFM) as porous artificial bone. In this study, the strength of the shear resistance force at the interface of the PVA-H and the TFM fabricated by injection molding and the changes in the mechanical properties of the PVA-H fabricated by high temperature during the injection-molding process were examined. The shear resistance force was strengthened markedly by using injection molding and no important deterioration of the PVA-H was found. Morphological examination of canine spines, to which artificial intervertebral discs made of the COD were implanted, showed good bonding of the COD with the vertebral bodies for an extended period of 30 months, and encouraged us to use the COD clinically.
- Published
- 2003
42. Adhesion between poly(ethylene-co-vinyl alcohol) (EVA) and titanium
- Author
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Sadami Tsutsumi, Chunyan Peng, Kazuaki Matsumura, Hiroo Iwata, Suong-Hyu Hyon, and Naoki Nakajima
- Subjects
Vinyl alcohol ,Materials science ,Surface Properties ,Biomedical Engineering ,chemistry.chemical_element ,Biocompatible Materials ,Biomaterials ,Contact angle ,chemistry.chemical_compound ,Ozone ,Shear strength ,Composite material ,poly(ethylene-co-vinyl alcohol) (EVA) ,chemistry.chemical_classification ,Titanium ,lap shear adhesive strength ,Adhesiveness ,Water ,Adhesion ,Polymer ,Hydrogen Peroxide ,Microscopy, Electron ,chemistry ,Surface modification ,Polyvinyls ,Adhesive ,Stress, Mechanical ,Polyethylenes ,T-peel strength - Abstract
Lap shear adhesive strength between titanium and various kinds of commercial polymers was evaluated. Among them, poly(ethylene-co-vinyl alcohol) (EVA) showed the highest strength. The results of electron spectroscopy for chemical analysis and the contact angle to water indicated that the high adhesive strength of EVA might be due to its high hydrophilicity. Water resistance of adhesion by water immersing at 37°C was investigated. In the case of polyurethane-titanium, the adhesive strength decreased immediately. In contrast, EVA-titanium kept its initial adhesive strength for at least up to 1 month. It was confirmed that surface modification of titanium by hydrogen peroxide enhanced the adhesive and peeling strength. It was based on not only an increase in surface adhesive area but also an increase in the hydrophilicity of titanium by the production of Ti-OH. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 309–315, 2002; DOI 10.1002/jbm.10051
- Published
- 2002
43. Development of a novel vitrification method for chondrocyte sheets
- Author
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Joji Mochida, T. Kanai, Masahito Watanabe, Masato Sato, Miki Maehara, Mami Kokubo, Hiroshi Nagashima, Suong-Hyu Hyon, Munetaka Yokoyama, Michio Sato, Hitomi Matsunari, and Kazuaki Matsumura
- Subjects
Cryoprotectant ,Cell Survival ,Cell Culture Techniques ,cell sheet ,engineering.material ,Biology ,Chondrocyte ,Cryopreservation ,chemistry.chemical_compound ,Cartilage repair ,Chondrocytes ,Coating ,Tissue engineering ,medicine ,Animals ,Vitrification ,Cell sheet therapy ,Dimethyl sulfoxide ,business.industry ,Methodology Article ,Embryo, Mammalian ,chondrocyte shee ,Biotechnology ,medicine.anatomical_structure ,chemistry ,tissue engineering ,engineering ,Rabbits ,business ,Ethylene glycol ,Chondrocyte sheet ,biomaterials ,Biomedical engineering - Abstract
Background There is considerable interest in using cell sheets for the treatment of various lesions as part of regenerative medicine therapy. Cell sheets can be prepared in temperature-responsive culture dishes and applied to injured tissue. For example, cartilage-derived cell sheets are currently under preclinical testing for use in treatment of knee cartilage injuries. The additional use of cryopreservation technology could increase the range and practicality of cell sheet therapies. To date, however, cryopreservation of cell sheets has proved impractical. Results Here we have developed a novel and effective method for cryopreserving fragile chondrocyte sheets. We modified the vitrification method previously developed for cryopreservation of mammalian embryos to vitrify a cell sheet through use of a minimum volume of vitrification solution containing 20% dimethyl sulfoxide, 20% ethylene glycol, 0.5 M sucrose, and 10% carboxylated poly-L-lysine. The principal feature of our method is the coating of the cell sheet with a viscous vitrification solution containing permeable and non-permeable cryoprotectants prior to vitrification in liquid nitrogen vapor. This method prevented fracturing of the fragile cell sheet even after vitrification and rewarming. Both the macro- and microstructures of the vitrified cell sheets were maintained without damage or loss of major components. Cell survival in the vitrified sheets was comparable to that in non-vitrified samples. Conclusions We have shown here that it is feasible to vitrify chondrocyte cell sheets and that these sheets retain their normal characteristics upon thawing. The availability of a practical cryopreservation method should make a significant contribution to the effectiveness and range of applications of cell sheet therapy.
- Published
- 2013
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