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Sample records for cell sheet engineering

  1. Cell sheet engineering

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    Masayuki Yamato

    2004-05-01

    Full Text Available We have developed ‘cell sheet engineering’ in order to avoid the limitations of tissue reconstruction using biodegradable scaffolds or single cell suspension injection. Our concept is tissue reconstruction, not from single cells, but from cell sheets. Cell sheets are prepared using temperature-responsive culture dishes. Temperature-responsive polymers are covalently grafted onto the dishes, allowing various types of cells to adhere and proliferate at 37°C. The cells spontaneously detach when the temperature is reduced below 32°C without the need for proteolytic enzymes. The confluent cells are noninvasively harvested as single, contiguous cell sheets with intact cell-cell junctions and deposited extracellular matrix (ECM. We have used these harvested cell sheets for various tissue reconstructions, including ocular surfaces, periodontal ligaments, cardiac patches, and bladder augmentation.

  2. Precisely Assembled Nanofiber Arrays as a Platform to Engineer Aligned Cell Sheets for Biofabrication

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    Vince Beachley

    2014-08-01

    Full Text Available A hybrid cell sheet engineering approach was developed using ultra-thin nanofiber arrays to host the formation of composite nanofiber/cell sheets. It was found that confluent aligned cell sheets could grow on uniaxially-aligned and crisscrossed nanofiber arrays with extremely low fiber densities. The porosity of the nanofiber sheets was sufficient to allow aligned linear myotube formation from differentiated myoblasts on both sides of the nanofiber sheets, in spite of single-side cell seeding. The nanofiber content of the composite cell sheets is minimized to reduce the hindrance to cell migration, cell-cell contacts, mass transport, as well as the foreign body response or inflammatory response associated with the biomaterial. Even at extremely low densities, the nanofiber component significantly enhanced the stability and mechanical properties of the composite cell sheets. In addition, the aligned nanofiber arrays imparted excellent handling properties to the composite cell sheets, which allowed easy processing into more complex, thick 3D structures of higher hierarchy. Aligned nanofiber array-based composite cell sheet engineering combines several advantages of material-free cell sheet engineering and polymer scaffold-based cell sheet engineering; and it represents a new direction in aligned cell sheet engineering for a multitude of tissue engineering applications.

  3. Latest status of the clinical and industrial applications of cell sheet engineering and regenerative medicine.

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    Egami, Mime; Haraguchi, Yuji; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2014-01-01

    Cell sheet engineering, which allows tissue engineering to be realized without the use of biodegradable scaffolds as an original approach, using a temperature-responsive intelligent surface, has been applied in regenerative medicine for various tissues, and a number of clinical studies have been already performed for life-threatening diseases. By using the results and findings obtained from the initial clinical studies, additional investigative clinical studies in several tissues with cell sheet engineering are currently in preparation stage. For treating many patients effectively by cell sheet engineering, an automated system integrating cell culture, cell-sheet fabrication, and layering is essential, and the system should include an advanced three-dimensional suspension cell culture system and an in vitro bioreactor system to scale up the production of cultured cells and fabricate thicker vascularized tissues. In this paper, cell sheet engineering, its clinical application, and further the authors' challenge to develop innovative cell culture systems under newly legislated regulatory platform in Japan are summarized and discussed.

  4. Facile fabrication of tissue-engineered constructs using nanopatterned cell sheets and magnetic levitation

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    Penland, Nisa; Choi, Eunpyo; Perla, Mikael; Park, Jungyul; Kim, Deok-Ho

    2017-02-01

    We report a simple and versatile method for in vitro fabrication of scaffold-free tissue-engineered constructs with predetermined cellular alignment, by combining magnetic cell levitation with thermoresponsive nanofabricated substratum (TNFS) based cell sheet engineering technique. The TNFS based nanotopography provides contact guidance cues for regulation of cellular alignment and enables cell sheet transfer, while magnetic nanoparticles facilitate the magnetic levitation of the cell sheet. The temperature-mediated change in surface wettability of the thermoresponsive poly(N-isopropylacrylamide), substratum enables the spontaneous detachment of cell monolayers, which can then be easily manipulated through use of a ring or disk shaped magnet. Our developed platform could be readily applicable to production of tissue-engineered constructs containing complex physiological structures for the study of tissue structure-function relationships, drug screening, and regenerative medicine.

  5. Engineering tubular bone using mesenchymal stem cell sheets and coral particles

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    Geng, Wenxin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Ma, Dongyang [Department of Oral and Maxillofacial Surgery, Lanzhou General Hospital, Lanzhou Command of PLA, BinHe 333 South Road, Lanzhou 730052 (China); Yan, Xingrong; Liu, Liangqi; Cui, Jihong; Xie, Xin; Li, Hongmin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Chen, Fulin, E-mail: chenfl@nwu.edu.cn [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China)

    2013-04-19

    Highlights: • We developed a novel engineering strategy to solve the limitations of bone grafts. • We fabricated tubular constructs using cell sheets and coral particles. • The composite constructs showed high radiological density and compressive strength. • These characteristics were similar to those of native bone. -- Abstract: The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects.

  6. Periodontal Ligament Cell Sheet Engineering: A new Possible Strategy to Promote Periodontal Regeneration

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    Dong-sheng Zhang

    2010-06-01

    Full Text Available Introduction: Osseointegration represents a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant without the periodontium. As a result, im-plant fracture or aggressive bone loss sometime occurs because the patient cannot feel the mechanical overloads exerted on the implant. Until now, no available method has been used to solve this problem.The hypothesis: Periodontal ligament (PDL cells are a desirable cell population capable of regenerating a functional periodontal at-tachment apparatus. Cell sheet engineering has emerged as a novel alternative approach for periodontal tissue engineering without the disruption of both critical cell surface proteins such as ion channels, growth factor receptors and cell-to-cell junction proteins. PDL cells can be isolated from an extracted tooth and can be cultured on temperature-responsive culture dishes at 37°C. Transplantable cell sheets can be harvested by reducing the temperature to 20°C, and would be transplanted into the implant beds before insertion of the implant.Evaluation of the hypothesis: Controlling the differentiation of PDL cell sheets to different functional peri-implant periodontal tissues is very difficult. Further studies are required to determine the fate of implanted cells. Fluorescence protein-labeled cell sheets would be a good approach to investigate the fate of the grafted cell sheet.

  7. N-Isopropylacrylamide-co-glycidylmethacrylate as a Thermoresponsive Substrate for Corneal Endothelial Cell Sheet Engineering

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    Bernadette K. Madathil

    2014-01-01

    Full Text Available Endothelial keratoplasty is a recent shift in the surgical treatment of corneal endothelial dystrophies, where the dysfunctional endothelium is replaced whilst retaining the unaffected corneal layers. To overcome the limitation of donor corneal shortage, alternative use of tissue engineered constructs is being researched. Tissue constructs with intact extracellular matrix are generated using stimuli responsive polymers. In this study we evaluated the feasibility of using the thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate polymer as a culture surface to harvest viable corneal endothelial cell sheets. Incubation below the lower critical solution temperature of the polymer allowed the detachment of the intact endothelial cell sheet. Phase contrast and scanning electron microscopy revealed the intact architecture, cobble stone morphology, and cell-to-cell contact in the retrieved cell sheet. Strong extracellular matrix deposition was also observed. The RT-PCR analysis confirmed functionally active endothelial cells in the cell sheet as evidenced by the positive expression of aquaporin 1, collagen IV, Na+-K+ ATPase, and FLK-1. Na+-K+ ATPase protein expression was also visualized by immunofluorescence staining. These results suggest that the in-house developed thermoresponsive culture dish is a suitable substrate for the generation of intact corneal endothelial cell sheet towards transplantation for endothelial keratoplasty.

  8. Oxygen plasma-treated thermoresponsive polymer surfaces for cell sheet engineering.

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    Shimizu, Kazunori; Fujita, Hideaki; Nagamori, Eiji

    2010-06-01

    Although cell sheet tissue engineering is a potent and promising method for tissue engineering, an increase of mechanical strength of a cell sheet is needed for easy manipulation of it during transplantation or 3D tissue fabrication. Previously, we developed a cell sheet-polymer film complex that had enough mechanical strength that can be manipulated even by tweezers (Fujita et al., 2009. Biotechnol Bioeng 103(2): 370-377). We confirmed the polymer film involving a temperature sensitive polymer and extracellular matrix (ECM) proteins could be removed by lowering temperature after transplantation, and its potential use in regenerative medicine was demonstrated. However, the use of ECM proteins conflicted with high stability in long-term storage and low cost. In the present study, to overcome these drawbacks, we employed the oxygen plasma treatment instead of using the ECM proteins. A cast and dried film of thermoresponsive poly-N-isopropylacrylamide (PNIPAAm) was fabricated and treated with high-intensity oxygen plasma. The cells became possible to adhere to the oxygen plasma-treated PNIPAAm surface, whereas could not to the inherent surface of bulk PNIPAAm without treatment. Characterizations of the treated surface revealed the surface had high stability. The surface roughness, wettability, and composition were changed, depending on the plasma intensity. Interestingly, although bulk PNIPAAm layer had thermoresponsiveness and dissolved below lower critical solution temperature (LCST), it was found that the oxygen plasma-treated PNIPAAm surface lost its thermoresponsiveness and remained insoluble in water below LCST as a thin layer. Skeletal muscle C2C12 cells could be cultured on the oxygen plasma-treated PNIPAAm surface, a skeletal muscle cell sheet with the insoluble thin layer could be released in the medium, and thus the possibility of use of the cell sheet for transplantation was demonstrated.

  9. Monosaccharide-responsive phenylboronate-polyol cell scaffolds for cell sheet and tissue engineering applications.

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    Rachamalla Maheedhar Reddy

    Full Text Available Analyte-responsive smart polymeric materials are of great interest and have been actively investigated in the field of regenerative medicine. Phenylboronate containing copolymers form gels with polyols under alkaline conditions. Monosaccharides, by virtue of their higher affinity towards boronate, can displace polyols and solubilize such gels. In the present study, we investigate the possibility of utilizing phenylboronate-polyol interactions at physiological pH in order to develop monosaccharide-responsive degradable scaffold materials for systems dealing with cells and tissues. Amine assisted phenylboronate-polyol interactions were employed to develop novel hydrogel and cryogel scaffolds at neutral pH. The scaffolds displayed monosaccharide inducible gel-sol phase transformability. In vitro cell culture studies demonstrated the ability of scaffolds to support cell adhesion, viability and proliferation. Fructose induced gel degradation is used to recover cells cultured on the hydrogels. The cryogels displayed open macroporous structure and superior mechanical properties. These novel phase transformable phenylboronate-polyol based scaffolds displayed a great potential for various cell sheet and tissue engineering applications. Their monosaccharide responsiveness at physiological pH is very useful and can be utilized in the fields of cell immobilization, spheroid culture, saccharide recognition and analyte-responsive drug delivery.

  10. Engineered bone marrow-derived cell sheets restore structure and function of radiation-injured rat urinary bladders.

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    Imamura, Tetsuya; Ogawa, Teruyuki; Minagawa, Tomonori; Yokoyama, Hitoshi; Nakazawa, Masaki; Nishizawa, Osamu; Ishizuka, Osamu

    2015-05-01

    factor mRNAs in the cell sheet-transplanted urinary bladders that were expressed greater than or equal to two-fold over the controls. In conclusion, cell sheet engineering has great potential to restore damaged urinary bladders.

  11. Middle ear mucosal regeneration with three-dimensionally tissue-engineered autologous middle ear cell sheets in rabbit model.

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    Yaguchi, Yuichiro; Murakami, Daisuke; Yamato, Masayuki; Hama, Takanori; Yamamoto, Kazuhisa; Kojima, Hiromi; Moriyama, Hiroshi; Okano, Teruo

    2016-03-01

    The likelihood of recurrent retraction and adhesion of newly formed tympanic membrane is high when middle ear mucosa is extensively lost during cholesteatoma and adhesive otitis media surgery. If rapid postoperative regeneration of the mucosa on the exposed bone surface can be achieved, prevention of recurrent eardrum adhesion and cholesteatoma formation, for which there has been no definitive treatment, can be expected. Suture-less transplantation of tissue-engineered mucosal cell sheets was examined immediately after the operation of otitis media surgery in order to quickly regenerate middle ear mucosa lost during surgery in a rabbit model. Transplantable middle ear mucosal cell sheets with a three-dimensional tissue architecture very similar to native middle ear mucosa were fabricated from middle ear mucosal tissue fragments obtained in an autologous manner from middle ear bulla on temperature-responsive culture surfaces. Immediately after the mucosa was resected from middle ear bone bulla inner cavity, mucosal cell sheets were grafted at the resected site. Both bone hyperplasia and granulation tissue formation were inhibited and early mucosal regeneration was observed in the cell sheet-grafted group, compared with the control group in which only mucosal removal was carried out and the bone surface exposed. This result indicates that tissue engineered mucosal cell sheets would be useful to minimize complications after the surgical operation on otitis media and future clinical application is expected.

  12. Simple suspension culture system of human iPS cells maintaining their pluripotency for cardiac cell sheet engineering.

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    Haraguchi, Yuji; Matsuura, Katsuhisa; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2015-12-01

    In this study, a simple three-dimensional (3D) suspension culture method for the expansion and cardiac differentiation of human induced pluripotent stem cells (hiPSCs) is reported. The culture methods were easily adapted from two-dimensional (2D) to 3D culture without any additional manipulations. When hiPSCs were directly applied to 3D culture from 2D in a single-cell suspension, only a few aggregated cells were observed. However, after 3 days, culture of the small hiPSC aggregates in a spinner flask at the optimal agitation rate created aggregates which were capable of cell passages from the single-cell suspension. Cell numbers increased to approximately 10-fold after 12 days of culture. The undifferentiated state of expanded hiPSCs was confirmed by flow cytometry, immunocytochemistry and quantitative RT-PCR, and the hiPSCs differentiated into three germ layers. When the hiPSCs were subsequently cultured in a flask using cardiac differentiation medium, expression of cardiac cell-specific genes and beating cardiomyocytes were observed. Furthermore, the culture of hiPSCs on Matrigel-coated dishes with serum-free medium containing activin A, BMP4 and FGF-2 enabled it to generate robust spontaneous beating cardiomyocytes and these cells expressed several cardiac cell-related genes, including HCN4, MLC-2a and MLC-2v. This suggests that the expanded hiPSCs might maintain the potential to differentiate into several types of cardiomyocytes, including pacemakers. Moreover, when cardiac cell sheets were fabricated using differentiated cardiomyocytes, they beat spontaneously and synchronously, indicating electrically communicative tissue. This simple culture system might enable the generation of sufficient amounts of beating cardiomyocytes for use in cardiac regenerative medicine and tissue engineering.

  13. Sympathetic Innervation Induced in Engrafted Engineered Cardiomyocyte Sheets by Glial Cell Line Derived Neurotrophic Factor In Vivo

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    Xian-ming Fu

    2013-01-01

    Full Text Available The aim of myocardial tissue engineering is to repair or regenerate damaged myocardium with engineered cardiac tissue. However, this strategy has been hampered by lack of functional integration of grafts with native myocardium. Autonomic innervation may be crucial for grafts to function properly with host myocardium. In this study, we explored the feasibility of in vivo induction of autonomic innervation to engineered myocardial tissue using genetic modulation by adenovirus encoding glial cell line derived neurotrophic factor (GDNF. GFP-transgene (control group or GDNF overexpressing (GDNF group engineered cardiomyocyte sheets were transplanted on cryoinjured hearts in rats. Nerve fibers in the grafts were examined by immunohistochemistry at 1, 2, and 4 weeks postoperatively. Growth associated protein-43 positive growing nerves and tyrosine hydroxylase positive sympathetic nerves were first detected in the grafts at 2 weeks postoperatively in control group and 1 week in GDNF group. The densities of growing nerve and sympathetic nerve in grafts were significantly increased in GDNF group. No choline acetyltransferase immunopositive parasympathetic nerves were observed in grafts. In conclusion, sympathetic innervation could be effectively induced into engrafted engineered cardiomyocyte sheets using GDNF.

  14. Initiated chemical vapor deposition of thermoresponsive poly(N-vinylcaprolactam) thin films for cell sheet engineering.

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    Lee, Bora; Jiao, Alex; Yu, Seungjung; You, Jae Bem; Kim, Deok-Ho; Im, Sung Gap

    2013-08-01

    Poly(N-vinylcaprolactam) (PNVCL) is a thermoresponsive polymer known to be nontoxic, water soluble and biocompatible. Here, PNVCL homopolymer was successfully synthesized for the first time by use of a one-step vapor-phase process, termed initiated chemical vapor deposition (iCVD). Fourier transform infrared spectroscopy results showed that radical polymerization took place from N-vinylcaprolactam monomers without damaging the functional caprolactam ring. A sharp lower critical solution temperature transition was observed at 31°C from the iCVD poly(N-vinylcaprolactam) (PNVCL) film. The thermoresponsive PNVCL surface exhibited a hydrophilic/hydrophobic alteration with external temperature change, which enabled the thermally modulated attachment and detachment of cells. The conformal coverage of PNVCL film on various substrates with complex topography, including fabrics and nanopatterns, was successfully demonstrated, which can further be utilized to fabricate cell sheets with aligned cell morphology. The advantage of this system is that cells cultured on such thermoresponsive surfaces could be recovered as an intact cell sheet by simply lowering the temperature, eliminating the need for conventional enzymatic treatments.

  15. Scaffold Sheet Design Strategy for Soft Tissue Engineering

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    Liping Tang

    2010-02-01

    Full Text Available Creating heterogeneous tissue constructs with an even cell distribution and robust mechanical strength remain important challenges to the success of in vivo tissue engineering. To address these issues, we are developing a scaffold sheet tissue engineering strategy consisting of thin (~200 μm, strong, elastic, and porous crosslinked urethane- doped polyester (CUPE scaffold sheets that are bonded together chemically or through cell culture. Suture retention of the tissue constructs (four sheets fabricated by the scaffold sheet tissue engineering strategy is close to the surgical requirement (1.8 N rendering their potential for immediate implantation without a need for long cell culture times. Cell culture results using 3T3 fibroblasts show that the scaffold sheets are bonded into a tissue construct via the extracellular matrix produced by the cells after 2 weeks of in vitro cell culture.

  16. Cell sheet engineering: solvent effect on nanometric grafting of poly-N-isopropylacrylamide onto polystyrene substrate under ultraviolet radiation

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    Esmaeil Biazar

    2011-02-01

    potential as a biomaterial for cell sheet engineering.Keywords: nanometric grafting, solvent effect, poly-n-isopropylacrylamide, polystyrene film, ultraviolet radiation

  17. Ocular surface reconstruction with a tissue-engineered nasal mucosal epithelial cell sheet for the treatment of severe ocular surface diseases.

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    Kobayashi, Masakazu; Nakamura, Takahiro; Yasuda, Makoto; Hata, Yuiko; Okura, Shoki; Iwamoto, Miyu; Nagata, Maho; Fullwood, Nigel J; Koizumi, Noriko; Hisa, Yasuo; Kinoshita, Shigeru

    2015-01-01

    Severe ocular surface diseases (OSDs) with severe dry eye can be devastating and are currently some of the most challenging eye disorders to treat. To investigate the feasibility of using an autologous tissue-engineered cultivated nasal mucosal epithelial cell sheet (CNMES) for ocular surface reconstruction, we developed a novel technique for the culture of nasal mucosal epithelial cells expanded ex vivo from biopsy-derived human nasal mucosal tissues. After the protocol, the CNMESs had 4-5 layers of stratified, well-differentiated cells, and we successfully generated cultured epithelial sheets, including numerous goblet cells. Immunohistochemistry confirmed the presence of keratins 3, 4, and 13; mucins 1, 16, and 5AC; cell junction and basement membrane assembly proteins; and stem/progenitor cell marker p75 in the CNMESs. We then transplanted the CNMESs onto the ocular surfaces of rabbits and confirmed the survival of this tissue, including the goblet cells, up to 2 weeks. The present report describes an attempt to overcome the problems of treating severe OSDs with the most severe dry eye by treating them using tissue-engineered CNMESs to supply functional goblet cells and to stabilize and reconstruct the ocular surface. The present study is a first step toward assessing the use of tissue-engineered goblet-cell transplantation of nonocular surface origin for ocular surface reconstruction.

  18. Engineering β-sheet peptide assemblies for biomedical applications.

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    Yu, Zhiqiang; Cai, Zheng; Chen, Qiling; Liu, Menghua; Ye, Ling; Ren, Jiaoyan; Liao, Wenzhen; Liu, Shuwen

    2016-03-01

    Hydrogels have been widely studied in various biomedical applications, such as tissue engineering, cell culture, immunotherapy and vaccines, and drug delivery. Peptide-based nanofibers represent a promising new strategy for current drug delivery approaches and cell carriers for tissue engineering. This review focuses on the recent advances in the use of self-assembling engineered β-sheet peptide assemblies for biomedical applications. The applications of peptide nanofibers in biomedical fields, such as drug delivery, tissue engineering, immunotherapy, and vaccines, are highlighted. The current challenges and future perspectives for self-assembling peptide nanofibers in biomedical applications are discussed.

  19. Laminin-521 Promotes Rat Bone Marrow Mesenchymal Stem Cell Sheet Formation on Light-Induced Cell Sheet Technology

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    Zhiwei Jiang

    2017-01-01

    Full Text Available Rat bone marrow mesenchymal stem cell sheets (rBMSC sheets are attractive for cell-based tissue engineering. However, methods of culturing rBMSC sheets are critically limited. In order to obtain intact rBMSC sheets, a light-induced cell sheet method was used in this study. TiO2 nanodot films were coated with (TL or without (TN laminin-521. We investigated the effects of laminin-521 on rBMSCs during cell sheet culturing. The fabricated rBMSC sheets were subsequently assessed to study cell sheet viability, reattachment ability, cell sheet thickness, collagen type I deposition, and multilineage potential. The results showed that laminin-521 could promote the formation of rBMSC sheets with good viability under hyperconfluent conditions. Cell sheet thickness increased from an initial 26.7 ± 1.5 μm (day 5 up to 47.7 ± 3.0 μm (day 10. Moreover, rBMSC sheets maintained their potential of osteogenic, adipogenic, and chondrogenic differentiation. This study provides a new strategy to obtain rBMSC sheets using light-induced cell sheet technology.

  20. Poly(N-isopropylacrylamide) surface-grafted chitosan membranes as a new substrate for cell sheet engineering and manipulation.

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    da Silva, Ricardo M P; López-Pérez, Paula M; Elvira, Carlos; Mano, João F; Román, Julio San; Reis, Rui L

    2008-12-15

    The immobilization of poly(N-isopropylacrylamide) (PNIPAAm) on chitosan membranes was performed in order to render membranes with thermo-responsive surface properties. The aim was to create membranes suitable for cell culture and in which confluent cell sheets can be recovered by simply lowering the temperature. The chitosan membranes were immersed in a solution of the monomer that was polymerized via radical initiation. The composition of the polymerization reaction solvent, which was a mixture of a chitosan non-solvent (isopropanol) and a solvent (water), provided a tight control over the chitosan membranes swelling capability. The different swelling ratio, obtained at different solvent composition of the reaction mixture, drives simultaneously the monomer solubility and diffusion into the polymeric matrix, the polymerization reaction rate, as well as the eventual chain transfer to the side substituents of the pyranosyl groups of chitosan. A combined analysis of the modified membranes chemistry by proton nuclear magnetic resonance ((1)H-NMR), Fourier transform spectroscopy with attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) showed that it was possible to control the chitosan modification yield and depth in the solvent composition range between 75% and 100% of isopropanol. Plasma treatment was also applied to the original chitosan membranes in order to improve cell adhesion and proliferation. Chitosan membranes, which had been previously subjected to oxygen plasma treatment, were then modified by means of the previously described methodology. A human fetal lung fibroblast cell line was cultured until confluence on the plasma-treated thermo-responsive chitosan membranes and cell sheets were harvested lowering the temperature.

  1. Engineered three-dimensional rabbit oral epithelial-mesenchymal-muscular hybrid sheets

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    Shigeki Yamane; Kazunari Higa; Takashi Umezawa; Masamitsu Serikawa; Jun Shimazaki; Shinichi Abe

    2016-01-01

    Regenerative muscles are required for swallowing and mastication, and are important for functional recovery from diseases involving oral muscular defects. Therefore, we generated three-layer hybrid sheets, similar to oral mucosal structures containing submucosal muscles, using rabbit oral mucosa epithelial, mesenchymal, and myoblastic progenitor cells, and examined the structural proteins. Each cell type was obtained from rabbit oral mucosa using enzymatic digestion. Isolated mesenchymal and myoblastic cells were multi-differentiated into osteoblasts, adipocytes, and chondrocytes or myotubes. Isolated epithelial cells were cultured on collagen gels containing isolated mesenchymal cells for 2 weeks, and these epithelial–mesenchymal cell sheets were laminated onto myoblastic cell sheets. The engineered hybrid sheets were multi-stratified in the epithelial and myoblastic layers in a time-dependent manner, expressing intermediate cytoskeletal filament proteins of epithelium and muscle. Hybrid sheets also expressed extracellular matrix basement membrane proteins. Immature cell markers for epithelial and myoblastic cells were observed continuously in hybrid sheet cultures. We established engineered three-dimensional rabbit oral mucosa hybrid sheets containing each immature cell type in vitro.

  2. Methods for producing scaffold-free engineered cartilage sheets from auricular and articular chondrocyte cell sources and attachment to porous tantalum.

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    Whitney, G Adam; Mera, Hisashi; Weidenbecher, Mark; Awadallah, Amad; Mansour, Joseph M; Dennis, James E

    2012-08-01

    Scaffold-free cartilage engineering techniques may provide a simple alternative to traditional methods employing scaffolds. We previously reported auricular chondrocyte-derived constructs for use in an engineered trachea model; however, the construct generation methods were not reported in detail. In this study, methods for cartilage construct generation from auricular and articular cell sources are described in detail, and the resulting constructs are compared for use in a joint resurfacing model. Attachment of cartilage sheets to porous tantalum is also investigated as a potential vehicle for future attachment to subchondral bone. Large scaffold-free cartilage constructs were produced from culture-expanded chondrocytes from skeletally mature rabbits, and redifferentiated in a chemically-defined culture medium. Auricular constructs contained more glycosaminoglycan (39.6±12.7 vs. 9.7±1.9 μg/mg wet weight, mean and standard deviation) and collagen (2.7±0.45 vs. 1.1±0.2 μg/mg wet weight, mean and standard deviation) than articular constructs. Aggregate modulus was also higher for auricular constructs vs. articular constructs (0.23±0.07 vs. 0.12±0.03 MPa, mean and standard deviation). Attachment of constructs to porous tantalum was achieved by neocartilage ingrowth into tantalum pores. These results demonstrate that large scaffold-free neocartilage constructs can be produced from mature culture-expanded chondrocytes in a chemically-defined medium, and that these constructs can be attached to porous tantalum.

  3. A novel closed cell culture device for fabrication of corneal epithelial cell sheets.

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    Nakajima, Ryota; Kobayashi, Toyoshige; Moriya, Noboru; Mizutani, Manabu; Kan, Kazutoshi; Nozaki, Takayuki; Saitoh, Kazuo; Yamato, Masayuki; Okano, Teruo; Takeda, Shizu

    2015-11-01

    Automation technology for cell sheet-based tissue engineering would need to optimize the cell sheet fabrication process, stabilize cell sheet quality and reduce biological contamination risks. Biological contamination must be avoided in clinical settings. A closed culture system provides a solution for this. In the present study, we developed a closed culture device called a cell cartridge, to be used in a closed cell culture system for fabricating corneal epithelial cell sheets. Rabbit limbal epithelial cells were cultured on the surface of a porous membrane with 3T3 feeder cells, which are separate from the epithelial cells in the cell cartridges and in the cell-culture inserts as a control. To fabricate the stratified cell sheets, five different thicknesses of the membranes which were welded to the cell cartridge, were examined. Multilayered corneal epithelial cell sheets were fabricated in cell cartridges that were welded to a 25 µm-thick gas-permeable membrane, which was similar to the results with the cell-culture inserts. However, stratification of corneal epithelial cell sheets did not occur with cell cartridges that were welded to 100-300 µm-thick gas-permeable membranes. The fabricated cell sheets were evaluated by histological analyses to examine the expression of corneal epithelial-specific markers. Immunohistochemical analyses showed that a putative stem cell marker, p63, a corneal epithelial differentiation maker, CK3, and a barrier function marker, Claudin-1, were expressed in the appropriate position in the cell sheets. These results suggest that the cell cartridge is effective for fabricating corneal epithelial cell sheets.

  4. Cell sheet technology for regeneration of esophageal mucosa

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    Ryo Takagi; Teruo Okano; Masayuki Yamato; Nobuo Kanai; Daisuke Murakami; Makoto Kondo; Takaaki Ishii; Takeshi Ohki; Hideo Namiki; Masakazu Yamamoto

    2012-01-01

    The progress of tissue-engineering technology has realized development of new therapies to treat various disorders by using cultured cells.Cell-and tissue-based therapies have been successfully applied to human patients,and several tissue-engineered products have been approved by the regulatory agencies and are commercially available.In the review article,we describe our experience of development and clinical application of cell sheet-based regenerative medicine.Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been shown to be useful for removal of gastrointestinal neoplasms with less invasiveness compared with open surgery,especially in esophageal surgery.However,postoperative inflammation and stenosis are major complications observed after intensive mucosal resection.Therefore,we have developed novel regenerative medicine to prevent such complications and promote wound healing of esophageal mucosa after EMR or ESD.Transplantable oral mucosal epithelial cell sheets were fabricated from patients' own oral mucosa.Immediately after EMR or ESD,fabricated autologous cell sheets were endoscopically transplanted to the ulcer sites.We performed a preclinical study with a canine model.In human clinical settings,cell culture and cell sheet fabrication were performed in clean rooms according to good manufacturing practice guidelines,and pharmaceutical drugs were used as supplements to culture medium in place of research regents used in animal study.We believe that cell-based regenerative medicine would be useful to improve quality of life of patients after EMR or ESD.

  5. Polymer microlenses for quantifying cell sheet mechanics.

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    Miquelard-Garnier, Guillaume; Zimberlin, Jessica A; Sikora, Christian B; Wadsworth, Patricia; Crosby, Alfred

    2010-01-01

    Mechanical interactions between individual cells and their substrate have been studied extensively over the past decade; however, understanding how these interactions change as cells interact with neighboring cells in the development of a cell sheet, or early stage tissue, is less developed. We use a recently developed experimental technique for quantifying the mechanics of confluent cell sheets. Living cells are cultured on a thin film of polystyrene [PS], which is attached to a patterned substrate of crosslinked poly(dimethyl siloxane) [PDMS] microwells. As cells attach to the substrate and begin to form a sheet, they apply sufficient contractile force to buckle the PS film over individual microwells to form a microlens array. The curvature for each microlens is measured by confocal microscopy and can be related to the strain and stress applied by the cell sheet using simple mechanical analysis for the buckling of thin films. We demonstrate that this technique can provide insight into the important materials properties and length scales that govern cell sheet responses, especially the role of stiffness of the substrate. We show that intercellular forces can lead to significantly different behaviors than the ones observed for individual cells, where focal adhesion is the relevant parameter.

  6. Intelligent thermoresponsive substrate from modified overhead projection sheet as a tool for construction and support of cell sheets in vitro.

    Science.gov (United States)

    Nithya, Joseph; Kumar, P R Anil; Tilak, Prasad; Leena, Joseph; Sreenivasan, K; Kumary, T V

    2011-02-01

    Cell sheet engineering using thermoresponsive culture dishes allows harvesting of intact in vitro cell sheet. In this study, commercially available polyethylene terephthalate-based overhead projection transparency sheet (OHPS) was identified as a substrate for coating thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate) (NGMA) copolymer having lower critical solution temperature of 28°C. Since OHPS is highly hydrophobic and rigid, the surface was modified by alkali treatment (OHPS-M) to functionalize the surface with carboxyl and hydroxyl groups so as to make it more suitable for efficient coating of NGMA copolymer and cell culture. To impart thermoresponsiveness, OHPS-M was coated with NGMA (OHPS-MC). Surface morphology, surface chemistry, and thermoresponsive coating were analyzed by profilometry, scanning electron microscopy, water contact angle, and Fourier transform infrared spectroscopy. The cytotoxicity, cell adhesion, and proliferation on OHPS-M and OHPS-MC were analyzed using L929 cells. Specific cytocompatibility analysis was done using SIRC (Rabbit corneal) cells. Data revealed cytocompatible nature of OHPS-M and OHPS-MC. Suitability of OHPS-MC for cell sheet harvest and transfer efficiency was assessed using primary corneal cells. Corneal cell sheet constructs retrieved by temperature variation was characterized by reverse transcriptase polymerase chain reaction for markers specific to differentiated corneal cells (keratin 3 and keratin 12) and proliferating cell nuclear antigen, and assessed for viability using fluorescein diacetate staining, tissue architecture by scanning electron microscopy, and cell-cell contacts by connexin-43 staining. The retrieved cell sheets retained corneal epithelial characteristics such as keratin 3/12, viability, and tissue architecture with intact cell-cell contacts as in native tissue. The results proved that surface modification and coating with NGMA on OHPS offer a novel biocompatible thermosensitive

  7. Three-dimensional cardiac tissue fabrication based on cell sheet technology.

    Science.gov (United States)

    Masuda, Shinako; Shimizu, Tatsuya

    2016-01-15

    Cardiac tissue engineering is a promising therapeutic strategy for severe heart failure. However, conventional tissue engineering methods by seeding cells into biodegradable scaffolds have intrinsic limitations such as inflammatory responses and fibrosis arising from the degradation of scaffolds. On the other hand, we have developed cell sheet engineering as a scaffold-free approach for cardiac tissue engineering. Confluent cultured cells are harvested as an intact cell sheet using a temperature-responsive culture surface. By layering cardiac cell sheets, it is possible to form electrically communicative three-dimensional cardiac constructs. Cell sheet transplantation onto damaged hearts in several animal models has revealed improvements in heart functions. Because of the lack of vasculature, the thickness of viable cardiac cell sheet-layered tissues is limited to three layers. Pre-vascularized structure formation within cardiac tissue and multi-step transplantation methods has enabled the formation of thick vascularized tissues in vivo. Furthermore, development of original bioreactor systems with vascular beds has allowed reconstruction of three-dimensional cardiac tissues with a functional vascular structure in vitro. Large-scale culture systems to generate pluripotent stem cell-derived cardiac cells can create large numbers of cardiac cell sheets. Three-dimensional cardiac tissues fabricated by cell sheet engineering may be applied to treat heart disease and tissue model construction.

  8. FORMING FREEFORM SURFACE SHEET METAL USINGINTEGRATED REVERSE ENGINEERING TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    邢渊

    2001-01-01

    This paper presented a model of integrated reverse engineering system and set up its various data output flowchart, which is easy to be associated with other systems. The idea of integrated reverse engineer is introduced to the system of forming sheet metal with complex surface and using IDEF0 method sets up the function model of the system. The freeform surface reconstruction and CAD modeling of the system are described and decomposed. This paper discussed some problems, such as the feature expression, feature modeling and feature translation of the sheet parts and dies.

  9. Methods for Producing Scaffold-Free Engineered Cartilage Sheets from Auricular and Articular Chondrocyte Cell Sources and Attachment to Porous Tantalum

    OpenAIRE

    Whitney, G. Adam; Mera, Hisashi; Weidenbecher, Mark; Awadallah, Amad; Mansour, Joseph M.; Dennis, James E.

    2012-01-01

    Abstract Scaffold-free cartilage engineering techniques may provide a simple alternative to traditional methods employing scaffolds. We previously reported auricular chondrocyte-derived constructs for use in an engineered trachea model; however, the construct generation methods were not reported in detail. In this study, methods for cartilage construct generation from auricular and articular cell sources are described in detail, and the resulting constructs are compared for use in a joint res...

  10. Real-time, noninvasive optical coherence tomography of cross-sectional living cell-sheets in vitro and in vivo.

    Science.gov (United States)

    Kobayashi, Mari; Haraguchi, Yuji; Shimizu, Tatsuya; Mizuuchi, Kiminori; Iseki, Hiroshi

    2015-08-01

    Cell sheet technology has a history of application in regenerating various tissues, having successfully completed several clinical trials using autologous cell sheets. Tomographic analysis of living cell sheets is an important tool in the field of cell sheet-based regenerative medicine and tissue engineering to analyze the inner structure of layered living cells. Optical coherence tomography (OCT) is commonly used in ophthalmology to noninvasively analyze cross-sections of target tissues at high resolution. This study used OCT to conduct real-time, noninvasive analysis of living cell sheet cross sections. OCT showed the internal structure of cell sheets in tomographic images synthesized with backscatter signals from inside the living cell sheet without invasion or damage. OCT observations were used to analyze the static and dynamic behaviors of living cell sheets in vitro and in vivo including (1) the harvesting process of a C2C12 mouse skeletal myoblast sheet from a temperature-responsive culture surface; (2) cell-sheet adhesion onto various surfaces including a culture surface, a synthetic rubber glove, and the dorsal subcutaneous tissue of rats; and (3) the real-time propagation of beating rat cardiac cells within cardiac cell sheets. This study showed that OCT technology is a powerful tool in the field of cell sheet-based regenerative medicine and tissue engineering.

  11. Effect of bone marrow stromal cell sheet on the formation of tissue-engineered bone in dogs%犬骨髓基质细胞片层在构建组织工程骨中的作用

    Institute of Scientific and Technical Information of China (English)

    王玲玲; 李宁毅; 樊功为; 卜令学; 杨学财; 高振华

    2011-01-01

    目的:探讨犬骨髓基质细胞(bone marrow stromal cells,BMSCs)细胞片层在构建组织工程骨中的价值.方法:制备犬同种异体脱钙骨基质(dermineralized bone matrix,DBM).将人重组骨形态发生蛋白-2(rhBMP-2)复合到DBM上.抽取犬髂骨骨髓,采用密度梯度离心法分离犬骨髓基质细胞(BMSCs).将经成骨诱导的第3代细胞接种于温度反应性培养皿中,制备BMSCs细胞片层.用得到的BMSCs细胞片层包裹DBM/rhBMP-2/BMSCs复合体,植入犬背阔肌血运丰富的肌筋膜下为实验侧,以无BMSCs细胞片层包裹的DBM/rhBMP-加MSCs复合体为对照侧.术后4、8、12周取材,行组织学观察,评价体内异位成骨的情况.采用SPSS13.0软件,对数据进行两样本均数差别的t检验.结果:实验侧成骨面积大于对照侧,2组差异有显著性(P<0.05).术后12周,实验侧生成大量板层骨,有哈弗系统形成,骨髓腔内有红骨髓.对照侧有板层骨形成,无哈弗系统形成,骨髓腔内无红骨髓.结论:BMSCs细胞片层可促进具有致密板层骨和哈弗系统的组织工程骨的形成.%PURPOSE: To investigate the effect of bone marrow stromal cell sheet on the formation of tissue-engineered bone in dogs. METHODS: Demineralized bone matrix (DBM) were prepared from homologous bone. DBM was constituted with recombination human bone morphogenetic protein-2(rhBMP-2). And bone marrow stromal cells(BMSCs) were isolated from iliac bone of dogs with the method of density gradient centrifugation in vitro. BMSCs induced by osteogenic DMEM at passage 3 were incubated in the temperature-responsive culture dish to form BMSCs cell sheet. BMSCs cell sheet combined with DBM/rhBMP-2/BMSCs was implanted around the vessels of latissimus dorsi muscle in the experimental side,and DBM/rhBMP-2/BMSCs without BMSCs cell sheet was implanted around the vessels of latissimus dorsi muscle in the control side. 4,8,12 weeks after operation, the ectopic bone formation was investigated by

  12. Engineering cell-cell signaling.

    Science.gov (United States)

    Blagovic, Katarina; Gong, Emily S; Milano, Daniel F; Natividad, Robert J; Asthagiri, Anand R

    2013-10-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling on the basis of quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilize synthetic cells, advanced 'chassis' and predictive modeling to engineer the form and function of living tissues.

  13. Engineering Cell-Cell Signaling

    OpenAIRE

    Blagovic, Katarina; Gong, Emily S.; Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R

    2013-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cel...

  14. Experimental study of bone marrow stromal cell sheet on the construction of tissue-engineered bone%应用骨髓基质细胞片层构建组织工程骨的实验研究

    Institute of Scientific and Technical Information of China (English)

    王玲玲; 李宁毅; 樊功为; 卜令学; 袁荣涛; 高振华; 邢士超

    2011-01-01

    Objective To invesligale the effecl of bone marrow slromal cell sheet on the conslruclion of tissue-engineered bone in dogs. Methods Bone marrow slromal cells ( BMSCs) were isolaled from iliac bone of dogs with the melhod of density gradienl cenlrifu galion in vitro. Demineralized bone malrix( DBM) were prepared from homologuous bone. DBM was composiled wilh recombination hu man bone morphogenelic prolein-2( rhBMP-2). BMSCs induced by osleogenic DMEM al passage 3 were incubaled in the lemperalure responsive culture dish to make the BMSCs cell sheel. BMSCs cell sheel combined wilh DBM/rhBMP-2/BMSCs was implanted around the vessels of lattisimus dorsi muscle on the left side in the experiment group, and DBM/rhBMP-2/BMSCs without BMSCs cell sheet was implanted around the vessels of lattisimus dorsi muscle on the right side in the control group. 8,12,16 weeks after operation, the bone formation was investigated by histological observation. Results Osteogenesis result was experimental group > control group. Newly formed bone tissue in two groups were significantly different( P < 0. 05). 16 weeks after operation, a large number of lamellar bone and haversian system formed in experimental group,with red bone marrow in the bone marrow cavity. Lamellar bone formed in control group without haversian system and red bone marrow. Conclusions BMSCs cell sheet could promote the formation of tissue-engineered bone with dense lamellar bone and haversian system.%目的 探讨犬骨髓基质细胞(bone marrow stromal cells,BMSCs)片层在构建组织工程骨中的价值.方法 抽取犬髂骨骨髓,采用密度梯度离心法分离犬骨髓基质细胞(BMSCs).制备犬同种异体脱钙骨基质(dermineralized bone matrix,DBM).将人重组骨形态发生蛋白-2(recombination human bone morphogenetic protein-2,rhBMP-2)复合到DBM上.将经成骨诱导的第3代细胞接种于温度反应性培养皿中,制备BMSCs细胞片层.用得到的BMSCs细胞片层包裹DBM/rhBMP-2

  15. Construction of tissue engineering bone with bone marrow stromal cell sheets%应用骨髓基质细胞片层构建组织工程骨的实验研究

    Institute of Scientific and Technical Information of China (English)

    卜令学; 王艳辉; 李宁毅; 高振华; 陈欣; 荆恒

    2011-01-01

    目的 应用犬骨髓基质细胞片层构建组织工程骨,为临床提供组织工程骨来源.方法 分离培养传代犬骨髓基质细胞(bone marrow stromal cell,BMSC).将经成骨诱导的第3代BMSC接种于温度反应性培养皿中,制备BMSC细胞片层.制备犬同种异体脱钙骨基质(decalcification bone matrixes,DBM).实验用16只犬分为4组,每组4只,采用自身对照.将复合体BMSC片层-人重组骨形态生成蛋白2( rhBMP-2) -BMSC-DBM植入犬左侧背阔肌肌筋膜下为实验侧,同法右侧植入DBM-rhBMP-2-BMSC为对照侧.术后4、8、12、16周取材行组织学观察,评价体内异位成骨的情况.结果 实验侧成骨优于对照侧,成骨面积实验侧>对照侧,两侧差异有统计学意义(P<0.05).术后16周,实验侧板层骨连接成片,可见骨单位,骨髓腔内可见红骨髓.结论 BMSC细胞片层可促进功能性组织工程骨的形成.%Objective To construct tissue engineering bone with bone marrow stromal cell(BMSC)sheets of dogs.Methods BMSC were derived from dog bone marrow and cell sheets were prepared with temperature-responsive dishes after the cells were induced by osteogenesis.Allogeneic dogs decalcification bone matrixes(DBM) were prepared.Sixteen dogs were divided into 4 groups.The MSC cell sheets-rhBMP2-BMSC-DBM were implanted under the left latissimus dorsi myofascial as the experimental side; while the thBMP-2-BMSC-DBM were implanted in the right side as the control.Ectopic bone formation in vivo was evaluated by histological examination 4,8,12,16 weeks after operation.Results The osteogenesis in the experimental group was better than that in the control group.New bone area in the experimental side was larger than that in the control group,and the difference was significant ( P < 0.05 ).After 16 weeks,lamellar bone was connected into a film in the experimental group.Haversian system and red bone marrow could be seen.Conclusions BMSC cell sheets could promote the bone formation of

  16. Cell and Tissue Engineering

    CERN Document Server

    2012-01-01

    Cell and Tissue Engineering” introduces the principles and new approaches in cell and tissue engineering. It includes both the fundamentals and the current trends in cell and tissue engineering, in a way useful both to a novice and an expert in the field. The book is composed of 13 chapters all of which are written by the leading experts. It is organized to gradually assemble an insight in cell and tissue function starting form a molecular nano-level, extending to a cellular micro-level and finishing at the tissue macro-level. In specific, biological, physiological, biophysical, biochemical, medical, and engineering aspects are covered from the standpoint of the development of functional substitutes of biological tissues for potential clinical use. Topics in the area of cell engineering include cell membrane biophysics, structure and function of the cytoskeleton, cell-extracellular matrix interactions, and mechanotransduction. In the area of tissue engineering the focus is on the in vitro cultivation of ...

  17. The Integration of Nanotechnology and Biology for Cell Engineering: Promises and Challenges

    Directory of Open Access Journals (Sweden)

    Uma Maheswari Krishnan

    2013-10-01

    their variants, self-assembly, cell-printing techniques and cell sheet engineering, have all been elaborated in detail. These novel techniques may serve to overcome the challenges currently faced in tissue engineering.

  18. Porous poly(L-lactic acid) sheet prepared by stretching with starch particles as filler for tissue engineering.

    Science.gov (United States)

    Ju, Dandan; Han, Lijing; Li, Zonglin; Chen, Yunjing; Wang, Qingjiang; Bian, Junjia; Dong, Lisong

    2016-05-20

    Porous poly(L-lactic acid) (PLLA) sheets were prepared by uniaxial stretching PLLA sheets containing starch filler. Here, the starch filler content, stretching ratio, stretching rate and stretching temperature are important factors to influence the structure of the porous PLLA sheets, therefore, they have been investigated in detail. The pore size distribution and tortuosity were characterized by Mercury Intrusion Porosimetry. The results revealed that the porosity and pore size enlarged with the increase of the starch filler content and stretching ratio, while shrank with the rise of stretching temperature. On the other hand, the pore structure almost had no changes with the stretching rate ranging between 5 and 40 mm/min. In order to test and verify that the porous PLLA sheet was suitable for the tissue engineering, the starch particles were removed by selective enzymatic degradation and its in vitro biocompatibility to osteoblast-like MC3T3-E1 cells was investigated.

  19. Construction and characterization of osteogenic and vascular endothelial cell sheets from rat adipose-derived mesenchymal stem cells.

    Science.gov (United States)

    Zhang, Hualin; Yu, Na; Zhou, Yueli; Ma, Hairong; Wang, Juan; Ma, Xuerong; Liu, Jinsong; Huang, Jin; An, Yilin

    2016-10-01

    In this study, adipose-derived mesenchymal stem cells (ADSCs) were isolated from adipose tissues of rats. Flow cytometry identification showed that ADSCs of passage 3 highly expressed CD29 and CD44, but hardly expressed CD31 and CD45. Adipogenic, osteogenic, and chondrogenic differentiation were confirmed by the results of oil red O staining, alkaline phosphatase (ALP), and alcian blue staining, respectively. ADSCs at a density of 1×10(6)/cm(2) were cultured in the osteogenic medium and the osteogenic cell sheets could be obtained after 14 d. The cell sheets were positive with von kossa staining. The transmission electron microscopy (TEM) result showed that needle-like calcium salt crystals were deposited on the ECM. These results suggested that the osteogenic cell sheets may have potential osteogenesis ability. ADSCs at a density of 1×10(6)/cm(2) were cultured in the endothelial cell growth medium-2 and the endothelial cell sheets can be formed after 16 d of culture. The TEM image confirmed that the Weibel-Palade corpuscle was seen in the cells. The expression of CD31 was positive, suggesting that the endothelial cell sheets may have a strong ability to form blood vessels. In this study, two types of cell sheets with the potential abilities of osteogenesis and blood vessels formation were obtained by induced culture of ADSCs in vitro, which lays a foundation to build vascularized tissue engineered bone for the therapy of bone defects.

  20. Cell Factory Engineering.

    Science.gov (United States)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-03-22

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta-review provides general strategy guides for the broad range of applications of rational engineering of cell factories.

  1. 组织工程牙周膜细胞片的体内实验研究%An in vivo study of cell sheet technique for periodontal tissue engineering

    Institute of Scientific and Technical Information of China (English)

    王方; 谢诚; 吴国锋; 赵铱民

    2011-01-01

    目的:探索一种形成组织工程牙周膜的新方法并建立动物模型,为牙周组织工程奠定基础.方法:原代分离培养人牙周膜细胞,部分细胞复合明胶海绵设为对照组;另一部分细胞经特殊条件连续培养成细胞膜片设为实验组.2 组实验结果择优复合支架材料后植入裸鼠皮下,4 周后取材行组织病理检测.结果:经特殊条件连续培养的牙周膜细胞层叠交错相连形成具有良好的机械加工性能的生物膜片,该膜片经裸鼠体内培养形成牙周膜样组织,并在近羟基磷灰石支架侧有矿化的牙骨质样结构生成.结论:该方法制备的牙周膜细胞片在牙周组织工程具有良好的应用前景.%Objective: To develop a new way of preparation of periodontal ligament cell(PDLC) sheet and establish an animal test model. Methods: Primarily cultured human PDL cells were seeded on the surface of geffoam as the control group,and those continuously cultured in perti dishes as the experimental group. In control group no cell sheet was formed,but in experimental group cell sheets were developed. Then, the cell sheets were used to cover hydroxyapatite(HA) scafford and transplanted under the skin of immunocompromised mice. 4 weeks after implantation, the transplants were examined by histological methods ( HE staining and Masson's trichrome staining). Results: 4 weeks after implantation, PDLCs and matrix secreted by the cells formed a periodontal ligament like multilayer cell sheet on HA. Each layer of the whole sheet was connected tightly and could be shaped easily. Also, the periodontal ligament like tissue mineralized a layer of cementum like structure on HA scaffold. Conclusion: The multilayered cell sheet technique may be a novel strategy for periodontal regeneration.

  2. Addition of Adipose-Derived Stem Cells to Mesenchymal Stem Cell Sheets Improves Bone Formation at an Ectopic Site

    Directory of Open Access Journals (Sweden)

    Zhifa Wang

    2016-02-01

    Full Text Available To determine the effect of adipose-derived stem cells (ADSCs added to bone marrow-derived mesenchymal stem cell (MSC sheets on bone formation at an ectopic site. We isolated MSCs and ADSCs from the same rabbits. We then prepared MSC sheets for implantation with or without ADSCs subcutaneously in the backs of severe combined immunodeficiency (SCID mice. We assessed bone formation at eight weeks after implantation by micro-computed tomography and histological analysis. In osteogenic medium, MSCs grew to form multilayer sheets containing many calcium nodules. MSC sheets without ADSCs formed bone-like tissue; although neo-bone and cartilage-like tissues were sparse and unevenly distributed by eight weeks after implantation. In comparison, MSC sheets with ADSCs promoted better bone regeneration as evidenced by the greater density of bone, increased mineral deposition, obvious formation of blood vessels, large number of interconnected ossified trabeculae and woven bone structures, and greater bone volume/total volume within the composite constructs. Our results indicate that although sheets of only MSCs have the potential to form tissue engineered bone at an ectopic site, the addition of ADSCs can significantly increase the osteogenic potential of MSC sheets. Thus, the combination of MSC sheets with ADSCs may be regarded as a promising therapeutic strategy to stimulate bone regeneration.

  3. Cell Control Engineering

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1996-01-01

    The engineering process of creating cell control systems is described, and a Cell Control Engineering (CCE) concept is defined. The purpose is to assist people, representing different disciplines in the organisation, to implement cell controllers by addressing the complexity of having many systems...... in physically and logically different and changing manufacturing environments. The defined CCE concept combines state-of-the-art of commercially available enabling technologies for automation system software development, generic cell control models and guidelines for the complete engineering process....... It facilitates the understanding of the task and structure of cell controllers and uses this knowledge directly in the implementation of the system. By applying generic models CCE facilitates reuse of software components and maintenance of applications. In many enterprises, software makes up an increasing part...

  4. Cell Factory Engineering

    DEFF Research Database (Denmark)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely...... focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies...... in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta...

  5. Fuel cell engineering

    CERN Document Server

    Sundmacher

    2012-01-01

    Fuel cells are attractive electrochemical energy converters featuring potentially very high thermodynamic efficiency factors. The focus of this volume of Advances in Chemical Engineering is on quantitative approaches, particularly based on chemical engineering principles, to analyze, control and optimize the steady state and dynamic behavior of low and high temperature fuel cells (PEMFC, DMFC, SOFC) to be applied in mobile and stationary systems. * Updates and informs the reader on the latest research findings using original reviews * Written by leading industry experts and scholars * Review

  6. Influence of nanotopography on periodontal ligament stem cell functions and cell sheet based periodontal regeneration

    Directory of Open Access Journals (Sweden)

    Gao H

    2015-06-01

    Full Text Available Hui Gao,1–3,* Bei Li,1,2,* Lingzhou Zhao,4 Yan Jin1,21State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, 2Research and Development Center for Tissue Engineering, The Fourth Military Medical University, Xi’an, Shaanxi, 3Department of Stomatology, PLA 309th Hospital, Beijing, 4State Key Laboratory of Military Stomatology, Department of Periodontology, School of Stomatology, Fourth Military Medical University, Xi’an, Shaanxi, People’s Republic of China*These authors contributed equally to this workAbstract: Periodontal regeneration is an important part of regenerative medicine, with great clinical significance; however, the effects of nanotopography on the functions of periodontal ligament (PDL stem cells (PDLSCs and on PDLSC sheet based periodontal regeneration have never been explored. Titania nanotubes (NTs layered on titanium (Ti provide a good platform to study this. In the current study, the influence of NTs of different tube size on the functions of PDLSCs was observed. Afterward, an ectopic implantation model using a Ti/cell sheets/hydroxyapatite (HA complex was applied to study the effect of the NTs on cell sheet based periodontal regeneration. The NTs were able to enhance the initial PDLSC adhesion and spread, as well as collagen secretion. With the Ti/cell sheets/HA complex model, it was demonstrated that the PDLSC sheets were capable of regenerating the PDL tissue, when combined with bone marrow mesenchymal stem cell (BMSC sheets and HA, without the need for extra soluble chemical cues. Simultaneously, the NTs improved the periodontal regeneration result of the ectopically implanted Ti/cell sheets/HA complex, giving rise to functionally aligned collagen fiber bundles. Specifically, much denser collagen fibers, with abundant blood vessels as well as cementum-like tissue on the Ti surface, which well-resembled the structure of natural PDL

  7. 应用细胞片层技术构建组织工程骨修复犬下颌骨缺损的实验研究%A study of repairing mandibular defect using tissue engineering bone with bone marrow stem cells cell sheets in dog

    Institute of Scientific and Technical Information of China (English)

    姚超; 卜令学; 王科; 李宁毅; 王玲玲; 于跃远

    2012-01-01

    目的 应用骨髓间充质干细胞(BMSCs)细胞片层构建组织工程骨修复犬下颌骨缺损,探讨细胞片层在成骨中的作用.方法 采用密度梯度离心法分离和培养BMSCs,将BMSCs向成骨细胞诱导培养后,制备细胞片层.将细胞片层包裹到聚乳酸羟基乙酸共聚物(PLGA)支架表面,将其植入犬左侧下颌骨全层缺损中,对侧下颌骨植入无细胞片层包裹的支架复合体作同体对照.将16只犬分为4组,每组4只.术后4、8、12、16周分别处死1组,取材行大体及组织学观察.结果 实验侧成骨好于对照侧,术后16周,实验侧骨缺损大部分被新生骨替代,舌侧形成与正常骨相似的密质骨,与正常骨断端骨性愈合.实验侧新生骨光密度值大于对照侧,两者差异有统计学意义(P<0.05).实验侧可见较多哈弗氏系统及红骨髓,大量板层骨;对照侧哈弗氏系统较少.结论利用细胞片层技术可以构建出含板层骨结构的组织工程骨.%Objective To reconstruct mandibular defect using tissue engineering bone with bone mam? Stem cells (BMSCs) ceil sheets and investigate the effect of cell sheets on osteogeneeis. Methods BMSCs were isolated with the method of density gradient centrifugation from canine and cultured. BMSCs were induced to differentiate to osteo-blasts. BMSCs induced were fabricated to BMSCs cell sheets. The poly Qactic-co-glyeolic acid) (PLGA) wrapped with cell sheets were implanted into the mandibular defect in the left side (experimental side). PLGA wrapped without cell sheets were implanted into the right side (control side) of mandibles. 16 dogs were evenly divided into 4 groups, and one group of them was executed in 4, 8, 12. 16 weeks for gross investigation and histological observation. Results The osteogenesis of experimental side was better than that of control side. 16 weeks after implantation, most areas of the mandibular defect were replaced by fresh bone tissue. Compact bone similar to normal

  8. Evaluation and optimization of silicon sheet solar cells

    Science.gov (United States)

    Yoo, H.; Iles, P.; Tanner, D.; Pollock, G.; Uno, F.

    1980-01-01

    This paper describes the results and procedures to evaluate and improve the efficiency of solar cells made from various unconventional silicon sheets. The performance parameters included photovoltaic characteristics, spectral response, dark I-V characteristics, and diffusion length. The evaluation techniques used provided accurate and reliable information on sheet performance, and self-consistent results were obtained from the various measurement techniques used. Minority carrier diffusion length (L) was shown to be the ultimate limiting factor for the sheet cell performance (efficiency) and other back-up measurements confirmed this L-dependence. Limited efforts were made to identify defects which influence cell performance, and to use some improved process methods to increase cell efficiency.

  9. 细胞膜片技术在组织工程中的应用与研究进展%Application of cell sheet technology in tissue engineering

    Institute of Scientific and Technical Information of China (English)

    周术奎; 张楷乐; 王营; 傅强

    2016-01-01

    BACKGROUND:The cel sheet technology that is applied with the absence of scaffolds and enzymatic digestion can effectively repair tissue defects and improve organ function, by stimulating the secretion of extracelular matrix to form a dense membrane tissue. OBJECTIVE: To review the recent progress in cel sheet technology used in tissue engineering, thereby providing a new idea for relevant basic and clinical research. METHODS:The first author retrieved CNKI database, Wanfang database and PubMed with the keywords of “cel sheet, tissue engineering” in Chinese and English, respectively. Literature retrieval period was from January 2010 to July 2015. RESULTS AND CONCLUSION:Cel sheet technology combined with scaffold materials can be used for reconstruction and repair of tissues and organs. With the emerging of new technologies, multi-layer cel sheets are stratified to form a three-dimensional tissue for repair of soft tissues and organs. Compared with the monolayer cel sheet, the three-dimensional cel sheet that is laminated by same or different cel sheets has stronger regenerative ability and can be used to construct the ideal target tissue modelin vitro. Cel sheet technology combined with scaffolds can improve the mechanical strength of the composite and reduce cel loss, which has made great progress in the repair of tooth, bone and cartilage tissue. Currently, the cel sheet technology is at the laboratory stage, and little is reported on its clinical applications. We look forward to more innovative technologies that can be integrated into the cel sheet technology.%背景:细胞膜片技术无须支架材料和酶消化,通过刺激细胞外基质分泌形成致密膜片组织,能有效地修复组织缺损和改善器官功能。  目的:回顾近年来国内外细胞膜片技术应用于组织工程领域的新技术和新进展,为相关基础和临床研究提供新的思路。  方法:由第一作者检索CNKI全文数据库、

  10. Review: Gigacycle fatigue data sheets for advanced engineering materials

    Directory of Open Access Journals (Sweden)

    Koji Yamaguchi, Takayuki Abe, Kazuo Kobayashi, Etsuo Takeuchi, Hisashi Hirukawa, Yoshio Maeda, Nobuo Nagashima, Masao Hayakawa, Yoshiyuki Furuya, Masuo Shimodaira and Kensuke Miyahara

    2007-01-01

    Full Text Available Gigacycle fatigue data sheets have been published since 1997 by the National Institute for Materials Science. They cover several areas such as high-cycle-number fatigue for high-strength steels and titanium alloys, the fatigue of welded joints, and high-temperature fatigue for advanced ferritic heat-resistant steels. Some unique testing machines are used to run the tests up to an extremely high number of cycles such as 1010 cycles. A characteristic of gigacycle fatigue failure is that it is initiated inside smooth specimens; the fatigue strength decreases with increasing cycle number and the fatigue limit disappears, although ordinary fatigue failure initiates from the surface of a smooth specimen and a fatigue limit appears. For welded joints, fatigue failure initiates from the notch root of the weld, because a large amount of stress is concentrated at the weld toe. The fatigue strength of welded joints has been obtained for up to 108 cycles, which is an extremely high number of cycles for large welded joints. The project of producing gigacycle fatigue data sheets is still continuing and will take a few more years to complete.

  11. Microscale technologies for cell engineering

    CERN Document Server

    Gaharwar, Akhilesh

    2016-01-01

    This book offers readers cutting-edge research at the interface of polymer science and engineering, biomedical engineering, materials science, and biology. State-of-the-art developments in microscale technologies for cell engineering applications are covered, including technologies relevant to both pluripotent and adult stem cells, the immune system, and somatic cells of the animal and human origin. This book bridges the gap in the understanding of engineering biology at multiple length scale, including microenvironmental control, bioprocessing, and tissue engineering in the areas of cardiac, cartilage, skeletal, and vascular tissues, among others. This book also discusses unique, emerging areas of micropatterning and three-dimensional printing models of cellular engineering, and contributes to the better understanding of the role of biophysical factors in determining the cell fate. Microscale Technologies for Cell Engineering is valuable for bioengineers, biomaterial scientists, tissue engineers, clinicians,...

  12. Strengthening Interprofessional Requirements Engineering Through Action Sheets: A Pilot Study

    Science.gov (United States)

    Pohlmann, Sabrina; Heinze, Oliver; Brandner, Antje; Reiß, Christina; Kamradt, Martina; Szecsenyi, Joachim; Ose, Dominik

    2016-01-01

    Background The importance of information and communication technology for healthcare is steadily growing. Newly developed tools are addressing different user groups: physicians, other health care professionals, social workers, patients, and family members. Since often many different actors with different expertise and perspectives are involved in the development process it can be a challenge to integrate the user-reported requirements of those heterogeneous user groups. Nevertheless, the understanding and consideration of user requirements is the prerequisite of building a feasible technical solution. In the course of the presented project it proved to be difficult to gain clear action steps and priorities for the development process out of the primary requirements compilation. Even if a regular exchange between involved teams took place there was a lack of a common language. Objective The objective of this paper is to show how the already existing requirements catalog was subdivided into specific, prioritized, and coherent working packages and the cooperation of multiple interprofessional teams within one development project was reorganized at the same time. In the case presented, the manner of cooperation was reorganized and a new instrument called an Action Sheet was implemented. This paper introduces the newly developed methodology which was meant to smooth the development of a user-centered software product and to restructure interprofessional cooperation. Methods There were 10 focus groups in which views of patients with colorectal cancer, physicians, and other health care professionals were collected in order to create a requirements catalog for developing a personal electronic health record. Data were audio- and videotaped, transcribed verbatim, and thematically analyzed. Afterwards, the requirements catalog was reorganized in the form of Action Sheets which supported the interprofessional cooperation referring to the development process of a personal

  13. FORMING FREEFORM SURFACE SHEET METAL USINGINTEGRATED REVERSE ENGINEERING TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    XING; Yuan(

    2001-01-01

    [1]Puntambekar N V, Jablokow A G, Sommer H J. Unified review of 3D model generation for reverse engineering[J]. Computer Integrated Manufacturing System,1994,7(4):259~268.[2]Chikofsky E J. Reverse engineering and design recovery: a taxonomy[J]. IEEE Software,1990,6(3):13~17.[3]Chou Hon-yue. Application of reverse engineering in die and mold manufacturing[A]. 3rd Int Conf on Mould & Die Technique in Asia[C]. Taibei, China,1995.753~764.[4]Dipl-Ing Thomas Haller. Rapid mould and die making using reverse engineering and rapid prototyping[A]. 3rd Int Conf on Mould & Die Technique in Asia[C]. Taibei, China,1995.739~752.[5]Abella R J, Daschbach J M. Reverse engineering industrial applications[J]. Computers Ind Engng,1994,26(2):381~385.[6]Chen Y D, Tang X J. Automatic digitization of freeform curves by coordinate measuring machines[J]. ASME PED,1992,62:113~125.[7]Antonie van Rensburg. Implementing IDEF techniques as simulation modeling specifications[J]. Computers Ind Engng,1994,29(1-4):467~571.[8]Eastma C M, Fereshetian N. Informaiton models for use in product design: a comparison[J]. Computer-Aided Design.1994,26(7):551~572.

  14. Computer Modeling of Carbon Metabolism Enables Biofuel Engineering (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-09-01

    In an effort to reduce the cost of biofuels, the National Renewable Energy Laboratory (NREL) has merged biochemistry with modern computing and mathematics. The result is a model of carbon metabolism that will help researchers understand and engineer the process of photosynthesis for optimal biofuel production.

  15. Avidin-biotin-based approach to forming heterotypic cell clusters and cell sheets on a gas-permeable membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hamon, M; Ozawa, T; Montagne, K; Kojima, N; Ishii, R; Sakai, Y [Institute of Industrial Science (IIS), University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Yamaguchi, S; Nagamune, T [Department of Bioengineering, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ushida, T, E-mail: mzh0026@auburn.edu [Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-09-15

    Implantation of sheet-like liver tissues is a promising method in hepatocyte-based therapies, because angiogenesis is expected to occur upon implantation from the surrounding tissues. In this context, we introduce here a new methodology for the formation of a functional thick hepatic tissue usable for cell sheet technology. First, we report the formation of composite tissue elements in suspension culture. Composite elements were composed of human hepatoma Hep G2 cells and mouse NIH/3T3 fibroblasts which are important modulators for thick-tissue formation. To overcome the very low attachment and organization capability between different cells in suspension, we synthesized a new cell-to-cell binding molecule based on the avidin-biotin binding system that we previously applied to attach hepatocytes on artificial substrata. This newly synthesized biotin-conjugated biocompatible anchoring molecule was inserted in the plasma membrane of both cell types. NIH/3T3 cells were further conjugated with avidin and incubated with biotin-presenting Hep G2 cells to form highly composite tissue elements. Then, we seeded those elements on highly gas-permeable membranes at their closest packing density to induce the formation of a thick, composite, functional hepatic tissue without any perfusion. This methodology could open a new way to engineer implantable thick liver tissue sheets where different cell types are spatially organized and well supplied with oxygen.

  16. An Innovative Strategy for the Fabrication of Functional Cell Sheets Using an Electroactive Conducting Polymer.

    Science.gov (United States)

    Lee, HyungJae; Cho, Youngnam

    2015-01-01

    Here, we report the development of an electric field-assisted methodology for constructing 3D C2C12 cell sheets with the potential for cell surface modification. In this method, a conducting polymer, polypyrrole (Ppy), is electrodeposited via biotin doping, and then chemical conjugation of biotinylated bone morphogenetic protein 2 (BMP2) is achieved using a biotin-streptavidin cross-linker. Subsequently, C2C12 cells are cultured on BMP2-immobilized Ppy surfaces to induce interactions between cell surface receptors and bound BMP2 ligands. Following these procedures, layers of BMP2-immobilized cells can be easily detached from the Ppy surface by applying an electrical potential. This novel method results in high affinity, ligand-bound cell sheets, which exhibit homogeneous coverage with membrane-bound proteins and signal activation that occurs via maximal receptor accessibility. Using this strategy to engineer the cell surface with desirable ligands results in structures that mimic in vivo tissues; thus, the method reported here has potential applications in regenerative medicine and tissue engineering.

  17. Osteogenic Matrix Cell Sheets Facilitate Osteogenesis in Irradiated Rat Bone

    Directory of Open Access Journals (Sweden)

    Yoshinobu Uchihara

    2015-01-01

    Full Text Available Reconstruction of large bone defects after resection of malignant musculoskeletal tumors is a significant challenge in orthopedic surgery. Extracorporeal autogenous irradiated bone grafting is a treatment option for bone reconstruction. However, nonunion often occurs because the osteogenic capacity is lost by irradiation. In the present study, we established an autogenous irradiated bone graft model in the rat femur to assess whether osteogenic matrix cell sheets improve osteogenesis of the irradiated bone. Osteogenic matrix cell sheets were prepared from bone marrow-derived stromal cells and co-transplanted with irradiated bone. X-ray images at 4 weeks after transplantation showed bridging callus formation around the irradiated bone. Micro-computed tomography images at 12 weeks postoperatively showed abundant callus formation in the whole circumference of the irradiated bone. Histology showed bone union between the irradiated bone and host femur. Mechanical testing showed that the failure force at the irradiated bone site was significantly higher than in the control group. Our study indicates that osteogenic matrix cell sheet transplantation might be a powerful method to facilitate osteogenesis in irradiated bones, which may become a treatment option for reconstruction of bone defects after resection of malignant musculoskeletal tumors.

  18. Influence of nanotopography on periodontal ligament stem cell functions and cell sheet based periodontal regeneration.

    Science.gov (United States)

    Gao, Hui; Li, Bei; Zhao, Lingzhou; Jin, Yan

    2015-01-01

    Periodontal regeneration is an important part of regenerative medicine, with great clinical significance; however, the effects of nanotopography on the functions of periodontal ligament (PDL) stem cells (PDLSCs) and on PDLSC sheet based periodontal regeneration have never been explored. Titania nanotubes (NTs) layered on titanium (Ti) provide a good platform to study this. In the current study, the influence of NTs of different tube size on the functions of PDLSCs was observed. Afterward, an ectopic implantation model using a Ti/cell sheets/hydroxyapatite (HA) complex was applied to study the effect of the NTs on cell sheet based periodontal regeneration. The NTs were able to enhance the initial PDLSC adhesion and spread, as well as collagen secretion. With the Ti/cell sheets/HA complex model, it was demonstrated that the PDLSC sheets were capable of regenerating the PDL tissue, when combined with bone marrow mesenchymal stem cell (BMSC) sheets and HA, without the need for extra soluble chemical cues. Simultaneously, the NTs improved the periodontal regeneration result of the ectopically implanted Ti/cell sheets/HA complex, giving rise to functionally aligned collagen fiber bundles. Specifically, much denser collagen fibers, with abundant blood vessels as well as cementum-like tissue on the Ti surface, which well-resembled the structure of natural PDL, were observed in the NT5 and NT10 sample groups. Our study provides the first evidence that the nanotopographical cues obviously influence the functions of PDLSCs and improve the PDLSC sheet based periodontal regeneration size dependently, which provides new insight to the periodontal regeneration. The Ti/cell sheets/HA complex may constitute a good model to predict the effect of biomaterials on periodontal regeneration.

  19. 骨髓间充质干细胞膜片复合珊瑚支架构建管状组织工程骨的实验研究%Engineering tubular bone constructs using bone marrow mesenchymal stem cells sheets and natural coral

    Institute of Scientific and Technical Information of China (English)

    张蓉; 高瞻; 雷权; 王荣耀; 郭增良; 李猛

    2012-01-01

    目的:应用细胞膜片复合管状珊瑚材料,移植自体体内,构建具备特定形态的组织工程骨.方法:构建兔来源骨髓间充质干细胞膜片,与珊瑚支架复合,静置孵育24h后,移植动物自体背部皮下,以单纯珊瑚植入作对照组.术后4周、8周分别取材,行大体观察、扫描电镜及组织学分析其成骨能力.结果:体内培养4周和8周后,证实实验组有新骨形成;而单纯材料组空隙内为纤维组织,未见骨样组织.结论:骨髓间充质干细胞膜片与珊瑚支架材料复合,在自体体内可构建管状组织工程骨.%Objective In this study,mesenchymal stem cells (MSCs) sheets were assembled with tubular scaffolds made from natural coral (NA), for engineering of functional bone grafts. Methods MSCs were cultured to form a thin layer of cell sheet via osteogenic induction.Then.tubular long bones were constructed by wrapping the MSCs sheets on to scaffolds.In vivo, constructs were implanted subcutaneously in rabbits. Coral implants were acted as controls.The specimens were harvested and evaluated by gross examination,scanning electronic microscopy (SEM) analysis and histological examination 4 and 8 weeks after implantation. Results In vivo, SEM and histological examinations revealed neo trabecular bone were formed within the constructs in test group. In contrast, the NA was filled only with fibrous tissue in the control group.without evidence of bone formation. Conclusion These findings illustrate that large bone tissues similar to native bone can be regenerated utilizing sheet techniques in conjunction with NA.

  20. Flow visualization using the laser light sheet method in vehicle aerodynamics and combustion chamber engineering

    Science.gov (United States)

    Hentschel, Werner

    Laser light sheet flow visualization is applied in the automobile industry with a view to the reduction of air resistance. Using high power lasers a plane is cut out of the 3-D flow field and the course of flow in the plane is analyzed. In vehicle aerodynamics the flow phenomena are mainly visualized with smoke in the tail region of automobiles and in the wake, in planes parallel as well as perpendicular to the flow direction. For the investigation of flow phenomena in the combustion chamber of Otto and Diesel engines, the laser light sheet method is used on a series motor with optical access, the so-called flow motor. Typical results and requirements for future automated evaluation methods are discussed.

  1. A novel cell-sheet technology that achieves durable factor VIII delivery in a mouse model of hemophilia A.

    Science.gov (United States)

    Tatsumi, Kohei; Sugimoto, Mitsuhiko; Lillicrap, David; Shima, Midori; Ohashi, Kazuo; Okano, Teruo; Matsui, Hideto

    2013-01-01

    Gene- or cell-based therapies aimed at creating delivery systems for coagulation factor VIII (FVIII) protein have emerged as promising options for hemophilia A treatment. However, several issues remain to be addressed regarding the efficacies and adverse events of these new classes of therapies. To improve an existing cell-based therapy involving the subcutaneous transplantation of FVIII-transduced blood outgrowth endothelial cells (BOECs), we employed a novel cell-sheet technology that allows individual dispersed cells to form a thin and contiguous monolayer without traditional bioabsorbable scaffold matrices. Compared to the traditional methodology, our cell-sheet approach resulted in longer-term and 3-5-fold higher expression of FVIII (up to 11% of normal) in recipient hemophilia A mice that lacked a FVIII humoral immune response due to transient immunosuppression with cyclophosphamide. Histological studies revealed that the transplanted BOEC sheets were structured as flat clusters, supporting the long-term expression of therapeutic FVIII in plasma from an ectopic subcutaneous space. Our novel tissue-engineering approach using genetically modified BOEC sheets could aid in development of cell-based therapy that will allow safe and effective in vivo delivery of functional FVIII protein in patients with hemophilia A.

  2. A novel cell-sheet technology that achieves durable factor VIII delivery in a mouse model of hemophilia A.

    Directory of Open Access Journals (Sweden)

    Kohei Tatsumi

    Full Text Available Gene- or cell-based therapies aimed at creating delivery systems for coagulation factor VIII (FVIII protein have emerged as promising options for hemophilia A treatment. However, several issues remain to be addressed regarding the efficacies and adverse events of these new classes of therapies. To improve an existing cell-based therapy involving the subcutaneous transplantation of FVIII-transduced blood outgrowth endothelial cells (BOECs, we employed a novel cell-sheet technology that allows individual dispersed cells to form a thin and contiguous monolayer without traditional bioabsorbable scaffold matrices. Compared to the traditional methodology, our cell-sheet approach resulted in longer-term and 3-5-fold higher expression of FVIII (up to 11% of normal in recipient hemophilia A mice that lacked a FVIII humoral immune response due to transient immunosuppression with cyclophosphamide. Histological studies revealed that the transplanted BOEC sheets were structured as flat clusters, supporting the long-term expression of therapeutic FVIII in plasma from an ectopic subcutaneous space. Our novel tissue-engineering approach using genetically modified BOEC sheets could aid in development of cell-based therapy that will allow safe and effective in vivo delivery of functional FVIII protein in patients with hemophilia A.

  3. Tooth root regeneration using dental follicle cell sheets in combination with a dentin matrix - based scaffold.

    Science.gov (United States)

    Yang, Bo; Chen, Gang; Li, Jie; Zou, Qing; Xie, Dan; Chen, Yali; Wang, Hang; Zheng, Xiaohui; Long, Jie; Tang, Wei; Guo, Weihua; Tian, Weidong

    2012-03-01

    Stem cell mediated tissue engineering has been acknowledged as a prospective strategy for repairing and replacing damaged and lost tissues. However, the low survival rate of implanted stem cells proves to be a major challenge in the management of transplantation failures. While previous studies have indicated the effectiveness of tissue engineered cell sheets in improving the survival rate of implanted cells, we have recently demonstrated the use of treated dentin matrix (TDM) as a biological scaffold and dental follicle cells (DFCs) as the seeding cells for dentinogenesis and tooth root construction. This study proposes a strategy utilizing TDM with human dental follicle cell sheets (DFCSs) for root regeneration. The biological characteristics and changes of human DFCSs under the effect of TDM were studied with scanning electron microscopy, transmission electron microscopy, immunofluorescence microscopy, immunohistochemistry and quantitative real-time PCR. DFCSs combined with TDM were implanted subcutaneously into the dorsum of mice. Histological examination of the harvested grafts revealed a whirlpool-like alignment of the DFCs in multiple layers that were positive for COLI, integrinβ1, fibronectin and alkaline phosphatase (ALP), suggestive of the formation of a rich extracellular matrix. DFCSs, under the effect of TDM, highly expressed DMP-1 and bone sialoprotein (BSP), indicating their potential for odontogenesis and osteogenesis. Importantly, in vivo, TDM could induce and support DFCSs to develop new dentin-pulp like tissues and cementum-periodontal complexes that were positive for markers such as DSP, nestin and VIII factors, COLI and cementum attachment protein (CAP), implying successful root regeneration. Therefore, DFCSs combined with TDM may prove to be a better strategy for the construction of tooth root, and is a prospective approach that could be utilized for the treatment of root or tooth defect or loss in future.

  4. TRPV-1-mediated elimination of residual iPS cells in bioengineered cardiac cell sheet tissues.

    Science.gov (United States)

    Matsuura, Katsuhisa; Seta, Hiroyoshi; Haraguchi, Yuji; Alsayegh, Khaled; Sekine, Hidekazu; Shimizu, Tatsuya; Hagiwara, Nobuhisa; Yamazaki, Kenji; Okano, Teruo

    2016-02-18

    The development of a suitable strategy for eliminating remaining undifferentiated cells is indispensable for the use of human-induced pluripotent stem (iPS) cell-derived cells in regenerative medicine. Here, we show for the first time that TRPV-1 activation through transient culture at 42 °C in combination with agonists is a simple and useful strategy to eliminate iPS cells from bioengineered cardiac cell sheet tissues. When human iPS cells were cultured at 42 °C, almost all cells disappeared by 48 hours through apoptosis. However, iPS cell-derived cardiomyocytes and fibroblasts maintained transcriptional and protein expression levels, and cardiac cell sheets were fabricated after reducing the temperature. TRPV-1 expression in iPS cells was upregulated at 42 °C, and iPS cell death at 42 °C was TRPV-1-dependent. Furthermore, TRPV-1 activation through thermal or agonist treatment eliminated iPS cells in cardiac tissues for a final concentration of 0.4% iPS cell contamination. These findings suggest that the difference in tolerance to TRPV-1 activation between iPS cells and iPS cell-derived cardiac cells could be exploited to eliminate remaining iPS cells in bioengineered cell sheet tissues, which will further reduce the risk of tumour formation.

  5. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-01-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitu

  6. Osteogenesis of human adipose-derived stem cells on hydroxyapatite-mineralized poly(lactic acid) nanofiber sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Fu-Chen [Department of Health Developing and Health Marketing, Kainan University, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@thu.edu.tw [Department of Chemical and Materials Engineering, Tunghai University, Taiwan (China); Lai, Wen-Fu T., E-mail: Laitw@tmu.edu.tw [Graduate Institute of Clinical Medicine, Taipei Medical University, Taiwan (China)

    2014-12-01

    Electrospun fiber sheets with various orientations (random, partially aligned, and aligned) and smooth and roughened casted membranes were prepared. Hydroxyapatite (HA) crystals were in situ formed on these material surfaces via immersion in 10 × simulated body fluid solution. The size and morphology of the resulting fibers were examined using scanning electron microscopy. The average diameter of the fibers ranged from 225 ± 25 to 1050 ± 150 nm depending on the electrospinning parameters. Biological experiment results show that human adipose-derived stem cells exhibit different adhesion and osteogenic differentiation on the three types of fiber. The cell proliferation and osteogenic differentiation were best on the aligned fibers. Similar results were found for phosphorylated focal adhesion kinase expression. Electrospun poly(lactic acid) aligned fibers mineralized with HA crystals provide a good environment for cell growth and osteogenic differentiation and thus have great potential in the tissue engineering field. - Highlights: • hADSCs show higher adhesion and proliferation on HA-precipitate electrospun fiber sheets than those of the control membranes. • HA-mineralized fiber groups greatly improve cell growth and increase FAK and p-FAK expressions. • HA-precipitate electrospun fiber sheets present higher ALP and OC activity through the study periods. • Electrospun PLA fiber mineralized with HA provides a good environment for cell growth and osteogenic differentiation. • A simple immersion of electrospun fibers in 10 × SBF are a potential matrix for bone tissue engineering.

  7. Tissue engineering of blood vessels with endothelial cells differentiated from mouse embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    ZHEN XU; MIN XIONG SHEN; DONG ZHU MA; LI YING WANG; XI LIANG ZHA

    2003-01-01

    Endothelial cells (TEC3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8 × l06 smooth muscle cells (SMCs) obtained from rabbit arteries onto a sheet of nonwoven polyglycolic acid (PGA) fibers, which was used as a biodegradable polymer scaffold. After being cultured in DMEM medium for 7 days in vitro, SMCs grew well on the PGA fibers, and the cell-PGA sheet was then wrapped around a silicon tube, and implanted subcutaneously into nude mice. After 6~8 weeks, the silicon tube was replaced with another silicon tube in smaller diameter, and then the TEC3 cells (endothelial cells differentiated from mouse ES cells) were injected inside the engineered vessel tube as the test group. In the control group only culture medium was injected. Five days later, the engineered vessels were harvested for gross observation, histological and immunohistochemical analysis. The preliminary results demonstrated that the SMC-PGA construct could form a tubular structure in 6~8 weeks and PGA fibers were completely degraded. Histological and immunohistochemical analysis of the newly formed tissue revealed a typical blood vessel structure, including a lining of endothelial cells (ECs) on the lumimal surface and the presence of SMC and collagen in the wall. No EC lining was found in the tubes of control group. Therefore, the ECs differentiated from mouse ES cells can serve as seed cells for endothelium lining in tissue engineered blood vessels.

  8. Treatment of refractory cutaneous ulcers with mixed sheets consisting of peripheral blood mononuclear cells and fibroblasts

    Science.gov (United States)

    Ueno, Koji; Takeuchi, Yuriko; Samura, Makoto; Tanaka, Yuya; Nakamura, Tamami; Nishimoto, Arata; Murata, Tomoaki; Hosoyama, Tohru; Hamano, Kimikazu

    2016-01-01

    The purpose of this study was to confirm the therapeutic effects of mixed sheets consisting of peripheral blood mononuclear cells (PBMNCs) and fibroblasts on cutaneous skin ulcers. Vascular endothelial growth factor (VEGF) secretion in mixed cell sheets was much higher than in PBMNCs and fibroblasts. Concerning the mechanism, transforming growth factor beta 1 and platelet-derived growth factor BB secreted from PBMNCs enhanced VEGF production in fibroblasts. In wounds created on the backs of diabetic mice, the therapeutic effect of mixed cell sheets was similar to that of daily treatment with trafermin, a recombinant human basic fibroblast growth factor. Although abnormal granulation tissue and inflammatory cell infiltration were observed in trafermin-treated wounds, the transplantation of mixed cell sheets resulted in the natural anatomy of subcutaneous tissues. The expression patterns of identical wound-healing factors in wounds were different between mixed sheet-transfected and trafermin-treated animals. Because mixed cell sheets transplanted into full-thickness skin defects were eliminated in hosts by day 21 in syngeneic transplantation models, allogeneic transplantation was performed using mice with different genetic backgrounds. The wound-healing rates were similar between the mixed cell sheet and trafermin groups. Our data indicated that mixed cell sheets represent a promising therapeutic material for cutaneous ulcers. PMID:27329845

  9. Organic fuel cells and fuel cell conducting sheets

    Science.gov (United States)

    Masel, Richard I.; Ha, Su; Adams, Brian

    2007-10-16

    A passive direct organic fuel cell includes an organic fuel solution and is operative to produce at least 15 mW/cm.sup.2 when operating at room temperature. In additional aspects of the invention, fuel cells can include a gas remover configured to promote circulation of an organic fuel solution when gas passes through the solution, a modified carbon cloth, one or more sealants, and a replaceable fuel cartridge.

  10. Engineering the Polyketide Cell Factory

    DEFF Research Database (Denmark)

    Mølgaard, Louise

    sufficient titers. To improve the production of polyketides biological engineering principles have been applied for the development and engineering of microbial polyketide cell factories. The two biological hosts used for heterologous polyketide production were Aspergillus nidulans and Saccharomyces...... phosphopantetheinylase (PPTase). This versatile vector system can easily be used for expression of other polyketides of interest as well as extended to express whole gene clusters. After achieving proof of principle in terms of expression, the polyketide cell factory must be optimized. The optimization can be achieved...... characterization in bioreactors revealed that the yields of 6-MSA on biomass increased albeit not significantly. As a result of this it may be argued that there is still more work to be done in terms of model building in A. nidulans. Utilizing another well-established cell factory S. cerevisiae the capabilities...

  11. Hypoxia Created Human Mesenchymal Stem Cell Sheet for Prevascularized 3D Tissue Construction.

    Science.gov (United States)

    Zhang, Lijun; Xing, Qi; Qian, Zichen; Tahtinen, Mitchell; Zhang, Zhaoqiang; Shearier, Emily; Qi, Shaohai; Zhao, Feng

    2016-02-01

    3D tissue based on human mesenchymal stem cell (hMSC) sheets offers many interesting opportunities for regenerating multiple types of connective tissues. Prevascularizing hMSC sheets with endothelial cells (ECs) will improve 3D tissue performance by supporting cell survival and accelerating integration with host tissue. It is hypothesized that hypoxia cultured hMSC sheets can promote microvessel network formation and preserve stemness of hMSCs. This study investigates the vascularization of hMSC sheets under different oxygen tensions. It is found that the HN condition, in which hMSC sheets formed under physiological hypoxia (2% O2 ) and then cocultured with ECs under normoxia (20% O2 ), enables longer and more branched microvessel network formation. The observation is corroborated by higher levels of angiogenic factors in coculture medium. Additionally, the hypoxic hMSC sheet is more uniform and less defective, which facilitates fabrication of 3D prevascularized tissue construct by layering the prevascularized hMSC sheets and maturing in rotating wall vessel bioreactor. The hMSCs in the 3D construct still maintain multilineage differentiation ability, which indicates the possible application of the 3D construct for various connective tissues regeneration. These results demonstrate that hypoxia created hMSC sheets benefit the microvessel growth and it is feasible to construct 3D prevascularized tissue construct using the prevascularized hMSC sheets.

  12. NREL Showcases Hydrogen Internal Combustion Engine Bus, Helps DOE Set Standards for Outreach (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-11-01

    This fact sheet describes the National Renewable Energy Laboratory's (NREL's) accomplishments in showcasing a Ford hydrogen-powered internal combustion engine (H2ICE) bus at The Taste of Colorado festival in Denver. NREL started using its U.S. Department of Energy-funded H2ICE bus in May 2010 as the primary shuttle vehicle for VIP visitors, members of the media, and new employees. In September 2010, NREL featured the bus at The Taste of Colorado. This was the first major outreach event for the bus. NREL's educational brochure, vehicle wrap designs, and outreach efforts serve as a model for other organizations with DOE-funded H2ICE buses. Work was performed by the Hydrogen Education Group and Market Transformation Group in the Hydrogen Technologies and Systems Center.

  13. Genome engineering in human cells.

    Science.gov (United States)

    Song, Minjung; Kim, Young-Hoon; Kim, Jin-Soo; Kim, Hyongbum

    2014-01-01

    Genome editing in human cells is of great value in research, medicine, and biotechnology. Programmable nucleases including zinc-finger nucleases, transcription activator-like effector nucleases, and RNA-guided engineered nucleases recognize a specific target sequence and make a double-strand break at that site, which can result in gene disruption, gene insertion, gene correction, or chromosomal rearrangements. The target sequence complexities of these programmable nucleases are higher than 3.2 mega base pairs, the size of the haploid human genome. Here, we briefly introduce the structure of the human genome and the characteristics of each programmable nuclease, and review their applications in human cells including pluripotent stem cells. In addition, we discuss various delivery methods for nucleases, programmable nickases, and enrichment of gene-edited human cells, all of which facilitate efficient and precise genome editing in human cells.

  14. Cardiac tissue engineering and regeneration using cell-based therapy

    Directory of Open Access Journals (Sweden)

    Alrefai MT

    2015-05-01

    Full Text Available Mohammad T Alrefai,1–3 Divya Murali,4 Arghya Paul,4 Khalid M Ridwan,1,2 John M Connell,1,2 Dominique Shum-Tim1,2 1Division of Cardiac Surgery, 2Division of Surgical Research, McGill University Health Center, Montreal, QC, Canada; 3King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia; 4Department of Chemical and Petroleum Engineering, School of Engineering, University of Kansas, Lawrence, KS, USA Abstract: Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. Keywords: stem cells, cardiomyocytes, cardiac surgery, heart failure, myocardial ischemia, heart, scaffolds, organoids, cell sheet and tissue engineering

  15. Programming Surface Chemistry with Engineered Cells.

    Science.gov (United States)

    Zhang, Ruihua; Heyde, Keith C; Scott, Felicia Y; Paek, Sung-Ho; Ruder, Warren C

    2016-09-16

    We have developed synthetic gene networks that enable engineered cells to selectively program surface chemistry. E. coli were engineered to upregulate biotin synthase, and therefore biotin synthesis, upon biochemical induction. Additionally, two different functionalized surfaces were developed that utilized binding between biotin and streptavidin to regulate enzyme assembly on programmable surfaces. When combined, the interactions between engineered cells and surfaces demonstrated that synthetic biology can be used to engineer cells that selectively control and modify molecular assembly by exploiting surface chemistry. Our system is highly modular and has the potential to influence fields ranging from tissue engineering to drug development and delivery.

  16. An invention of thermo-responsive polymer surface, yielding cell sheet based regenerative therapies in cardiology and ophthalmology

    Directory of Open Access Journals (Sweden)

    Sawa Y

    2015-12-01

    Full Text Available The Invention: In vitro cell culture methodologies provide a conducive environment for the cells taken out of their native environment to grow and proliferate in a non-physiological environment, the culture dish. Research experiments have been focusing on various criteria for assessing how far it is possible to recapitulate the native extra-cellular environment in vitro. Scaffolds, culture media, growth factors and cell surface modified culture dishes are some of the components that provide a conducive environment for in vitro cell culture. Cells that are grown in culture dishes using conventional methodologies are usually detached using enzymatic treatment with Trypsin, Collagenase etc [1], to be transplanted when it comes to a clinical or experimental application. Such enzymes used in separating the cells may have some damaging effects to the cell membranes which might impair the cell function [1]. However, cells if can be grown as a monolayer and be harvested as a contiguous cell sheet, it is considered suitable for transplantation in certain specific applications. In addition to that, if enzymatic digestion which has some detrimental effects on the detached cells could be avoided, that is an added advantage. The work by Prof. Okano and team from the Tokyo Women's Medical University, Japan, on thermo-responsive polymer surfaces has yielded a solution which has both the advantages viz., detachability of cells grown as a monolayer in the form of a cell sheet, that too without the use of enzymes. Their research into biomaterials for more than two decades has yielded a thermo-responsive polymer, the poly(N-isopropylacrylamide (PIPAAm [1] coated culture dish for cell sheet engineering. In their technology, PIPAAm is polymerized and grafted to tissue culture polystyrene (TCPS dishes. Cells have been found to grow confluent on PIPAAm-TCPS at 37 °C. Once confluent as a monolayer, by merely reducing the temperature of the PIPAAm-TCPS to 20 °C, it

  17. Bioengineered periosteal progenitor cell sheets to enhance tendon-bone healing in a bone tunnel

    Directory of Open Access Journals (Sweden)

    Chih-Hsiang Chang

    2012-12-01

    Full Text Available Background: Tendon-bone tunnel healing is crucial for long term success in anterior cruciate liga­ment (ACL reconstruction. The periosteum contains osteochondral progenitor cells that can differenti­ate into osteoblasts and chondroblasts during tendon-bone healing. We developed a scaf­fold-free method using polymerized fibrin-coated dishes to make functional periosteal progenitor cell (PPC sheets. Bioengineered PPC sheets for enhancing tendon-bone healing were evaluated in an extra-articular bone tunnel model in rabbit. Methods: PPC derived from rabbit tibia periosteum, cultivated on polymerized fi­brin-coated dishes and harvested as PPC sheet. A confocal microscopy assay was used to evaluate the morphology of PPC sheets. PPC sheets as a periosteum to wrap around hamstring tendon grafts were pulled into a 3-mm diameter bone tunnel of tibia, and compared with a tendon graft without PPC sheets treatment. Rabbits were sacrificed at 4 and 8 weeks postoperatively for biochemical as­say and histological assay to demonstrate the enhancement of PPC sheets in tendon-bone healing. Results: PPC spread deposit on fibrin on the dish surface with continuous monolayer PPC was ob­served. Histological staining revealed that PPC sheets enhance collagen and glycosaminoglycans deposi­tion with fibrocartilage formation in the tendon-bone junction at 4 weeks. Collagen fiber with fibrocartilage formation at tendon-bone junction was also found at 8 weeks. Matured fibrocartilage and dense collagen fiber were formed at the tendon-bone interface at 8 weeks by Masson trichrome and Safranin-O staining Conclusions: Periosteal progenitor cell monolayer maintains the differentiated capacity and osteochon­dral potential in order to promote fibrocartilage formation in tendon-bone junction. Bioengi­neered PPC sheets can offer a new feasible therapeutic strategy of a novel approach to en­hance tendon-bone junction healing.

  18. Local Mechanical Stimulation of Mardin-Darby Canine Kidney Cell Sheets on Temperature-Responsive Hydrogel

    Directory of Open Access Journals (Sweden)

    Toshihiro Akaike

    2012-01-01

    Full Text Available Collective motion of cell sheets plays a role not only in development and repair, but also in devastating diseases such as cancer. However, unlike single-cell motility, collective motion of cell sheets involves complex cell-cell communication during migration; therefore, its mechanism is largely unknown. To elucidate propagation of signaling transduced by cell-cell interaction, we designed a hydrogel substrate that can cause local mechanical stretching of cell sheets. Poly (N-isopropyl acrylamide (PNIPAAm hydrogel is a temperature-responsive polymer gel whose volume changes isotropically in response to temperature changes below 37 °C. We designed a combined hydrogel substrate consisting of collagen-immobilized PNIPAAm as the local stimulation side and polyacrylamide (PAAm as the non-stimulation side to assess propagation of mechanical transduction. Mardin-Darby canine kidney (MDCK cells adhered to the collagen-immobilized PNIPAAm gel increased it area and were flattened as the gel swelled with temperature decrease. E-cadherin in these cells became undetectable in some domains, and actin stress fibers were more clearly observed at the cell base. In contrast, E-cadherin in cells adhered to the collagen-immobilized PAAm side was equally stained as that in cells adhered to the collagen-immobilized PAAm side even after temperature decrease. ERK1/2 MAPK activation of cells on the non-stimulated substrate occurred after partial stretching of the cell sheet suggesting the propagation of signaling. These results indicate that a change in the balance of mechanical tension induced by partial stretching of cell sheets leads to activation and propagation of the cell signaling.

  19. CellNet: network biology applied to stem cell engineering.

    Science.gov (United States)

    Cahan, Patrick; Li, Hu; Morris, Samantha A; Lummertz da Rocha, Edroaldo; Daley, George Q; Collins, James J

    2014-08-14

    Somatic cell reprogramming, directed differentiation of pluripotent stem cells, and direct conversions between differentiated cell lineages represent powerful approaches to engineer cells for research and regenerative medicine. We have developed CellNet, a network biology platform that more accurately assesses the fidelity of cellular engineering than existing methodologies and generates hypotheses for improving cell derivations. Analyzing expression data from 56 published reports, we found that cells derived via directed differentiation more closely resemble their in vivo counterparts than products of direct conversion, as reflected by the establishment of target cell-type gene regulatory networks (GRNs). Furthermore, we discovered that directly converted cells fail to adequately silence expression programs of the starting population and that the establishment of unintended GRNs is common to virtually every cellular engineering paradigm. CellNet provides a platform for quantifying how closely engineered cell populations resemble their target cell type and a rational strategy to guide enhanced cellular engineering.

  20. Low Sheet Resistance Counter Electrode in Dye-sensitized Solar Cell

    Institute of Scientific and Technical Information of China (English)

    Gui Qiang WANG; Rui Feng LIN; Miao WANG; Chang Neng ZHANG; Yuan LIN; Xu Rui XIAO; Xue Ping LI

    2004-01-01

    In order to search for the high efficiency and low sheet resistance counter electrode in dye-sensitized solar cell, we used Ti plate as the conducting substrate to prepare the counter electrode by thermal decomposition of H2PtCl6. Ti plate counter electrode shows low sheet resistance, good reflecting performance and matching kinetics. The dye-sensitized solar cell with the Ti plate counter electrode shows better photovoltaic performance than that of the cell with the fluorine-doped tin oxide-coated glass counter electrode.

  1. Calculated and Experimental Research of Sheet Resistances of Laser-Doped Silicon Solar Cells

    Science.gov (United States)

    Li, Tao; Wang, Wen-Jing

    2015-02-01

    The calculated and experimental research of sheet resistances of crystalline silicon solar cells by dry laser doping is investigated. The nonlinear numerical model on laser melting of crystalline silicon and liquid-phase diffusion of phosphorus atoms by dry laser doping is analyzed by the finite difference method implemented in MATLAB. The melting period and melting depth of crystalline silicon as a function of laser energy density is achieved. The effective liquid-phase diffusion of phosphorus atoms in melting silicon by dry laser doping is confirmed by the rapid decrease of sheet resistances in experimental measurement. The plateau of sheet resistances is reached at around 15Ω/□. The calculated sheet resistances as a function of laser energy density is obtained and the calculated results are in good agreement with the corresponding experimental measurement. Due to the successful verification by comparison between experimental measurement and calculated results, the simulation results could be used to optimize the virtual laser doping parameters.

  2. Bay Area Transit Agencies Propel Fuel Cell Buses Toward Commercialization (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-01

    This fact sheet describes the Zero Emission Bay Area (ZEBA) demonstration of the next generation of fuel cells buses. Several transit agencies in the San Francisco Bay Area are participating in demonstrating the largest single fleet of fuel cell buses in the United States.

  3. Engineering Stem Cells for Biomedical Applications.

    Science.gov (United States)

    Yin, Perry T; Han, Edward; Lee, Ki-Bum

    2016-01-07

    Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer.

  4. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming Analysis, Simulation and Engineering Applications

    CERN Document Server

    Hu, Ping; Liu, Li-zhong; Zhu, Yi-guo

    2013-01-01

    Over the last 15 years, the application of innovative steel concepts in the automotive industry has increased steadily. Numerical simulation technology of hot forming of high-strength steel allows engineers to modify the formability of hot forming steel metals and to optimize die design schemes. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming focuses on hot and cold forming theories, numerical methods, relative simulation and experiment techniques for high-strength steel forming and die design in the automobile industry. Theories, Methods and Numerical Technology of Sheet Metal Cold and Hot Forming introduces the general theories of cold forming, then expands upon advanced hot forming theories and simulation methods, including: • the forming process, • constitutive equations, • hot boundary constraint treatment, and • hot forming equipment and experiments. Various calculation methods of cold and hot forming, based on the authors’ experience in commercial CAE software f...

  5. Development of 3D in vitro platform technology to engineer mesenchymal stem cells.

    Science.gov (United States)

    Hosseinkhani, Hossein; Hong, Po-Da; Yu, Dah-Shyong; Chen, Yi-Ru; Ickowicz, Diana; Farber, Ira-Yudovin; Domb, Abraham J

    2012-01-01

    This study aims to develop a three-dimensional in vitro culture system to genetically engineer mesenchymal stem cells (MSC) to express bone morphogenic protein-2. We employed nanofabrication technologies borrowed from the spinning industry, such as electrospinning, to mass-produce identical building blocks in a variety of shapes and sizes to fabricate electrospun nanofiber sheets comprised of composites of poly (glycolic acid) and collagen. Homogenous nanoparticles of cationic biodegradable natural polymer were formed by simple mixing of an aqueous solution of plasmid DNA encoded bone morphogenic protein-2 with the same volume of cationic polysaccharide, dextran-spermine. Rat bone marrow MSC were cultured on electrospun nanofiber sheets comprised of composites of poly (glycolic acid) and collagen prior to the incorporation of the nanoparticles into the nanofiber sheets. Bone morphogenic protein-2 was significantly detected in MSC cultured on nanofiber sheets incorporated with nanoparticles after 2 days compared with MSC cultured on nanofiber sheets incorporated with naked plasmid DNA. We conclude that the incorporation of nanoparticles into nanofiber sheets is a very promising strategy to genetically engineer MSC and can be used for further applications in regenerative medicine therapy.

  6. Development of 3D in vitro platform technology to engineer mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Hosseinkhani H

    2012-06-01

    Full Text Available Hossein Hosseinkhani,1 Po-Da Hong,1 Dah-Shyong Yu,2 Yi-Ru Chen,3 Diana Ickowicz,4 Ira-Yudovin Farber,4 Abraham J Domb41Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology (TAIWANTECH, 2Nanomedicine Research Center, National Defense Medical Center, Taipei, Taiwan, 3Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan, 4Institute of Drug Research, The Center for Nanoscience and Nanotechnology, School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, IsraelAbstract: This study aims to develop a three-dimensional in vitro culture system to genetically engineer mesenchymal stem cells (MSC to express bone morphogenic protein-2. We employed nanofabrication technologies borrowed from the spinning industry, such as electrospinning, to mass-produce identical building blocks in a variety of shapes and sizes to fabricate electrospun nanofiber sheets comprised of composites of poly (glycolic acid and collagen. Homogenous nanoparticles of cationic biodegradable natural polymer were formed by simple mixing of an aqueous solution of plasmid DNA encoded bone morphogenic protein-2 with the same volume of cationic polysaccharide, dextran-spermine. Rat bone marrow MSC were cultured on electrospun nanofiber sheets comprised of composites of poly (glycolic acid and collagen prior to the incorporation of the nanoparticles into the nanofiber sheets. Bone morphogenic protein-2 was significantly detected in MSC cultured on nanofiber sheets incorporated with nanoparticles after 2 days compared with MSC cultured on nanofiber sheets incorporated with naked plasmid DNA. We conclude that the incorporation of nanoparticles into nanofiber sheets is a very promising strategy to genetically engineer MSC and can be used for further applications in regenerative medicine therapy.Keywords: 3D culture, nanoparticles, nanofibers, polycations, tissue engineering

  7. Rapid cell sheet detachment using spin-coated pNIPAAm films retained on surfaces by an aminopropyltriethoxysilane network.

    Science.gov (United States)

    Patel, Nikul G; Cavicchia, John P; Zhang, Ge; Zhang Newby, Bi-min

    2012-07-01

    The ability to harvest cell sheets grown on thermoresponsive polymers, such as poly(N-isopropylacrylamide) (pNIPAAm), has been widely studied for use in tissue engineering applications. pNIPAAm is of special interest because of the phase change that it undergoes in a physiologically relevant temperature range. Two primary approaches have been adopted to graft pNIPAAm chains covalently onto tissue culture polystyrene dishes: electron beam irradiation and plasma polymerization. These approaches often involve non-easily accessible (e.g. e-beam) facilities and complicated procedures that have hindered most tissue culture laboratories in adopting this technology for their specific applications. In this study, we developed a simple and cost-effective approach to create thermoresponsive surfaces using commercially available pNIPAAm. Using a simple spin-coating technique, thermoresponsive thin films were deposited on glass slides or silicon wafers using pNIPAAm blended with a small amount of 3-aminopropyltriethoxysilane (APTES), which enhances the retention of pNIPAAm on the surface. We found that the thermoresponsive films created using our method support cell attachment and proliferation without additional adhesive proteins as well as cell sheet detachment within minutes.

  8. Stem cells in bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Jeong Min [Department of Preventive and Social Dentistry and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Byung-Chul; Park, Jae-Hong; Kwon, Il Keun; Hwang, Yu-Shik [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Mantalaris, Anathathios, E-mail: yshwang@khu.ac.k [Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2010-12-15

    Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. (topical review)

  9. Mesenchymal Stem Cells and Tooth Engineering

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Ling Ye; Xue-dong Zhou

    2009-01-01

    Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.

  10. Stem cell engineering a WTEC global assessment

    CERN Document Server

    Loring, Jeanne; McDevitt, Todd; Palecek, Sean; Schaffer, David; Zandstra, Peter

    2014-01-01

    This book describes a global assessment of stem cell engineering research, achieved through site visits by a panel of experts to leading institutes, followed by dedicated workshops. The assessment made clear that engineers and the engineering approach with its quantitative, system-based thinking can contribute much to the progress of stem cell research and development. The increased need for complex computational models and new, innovative technologies, such as high-throughput screening techniques, organ-on-a-chip models and in vitro tumor models require an increasing involvement of engineers and physical scientists. Additionally, this book will show that although the US is still in a leadership position in stem cell engineering, Asian countries such as Japan, China and Korea, as well as European countries like the UK, Germany, Sweden and the Netherlands are rapidly expanding their investments in the field. Strategic partnerships between countries could lead to major advances of the field and scalable expansi...

  11. Improving the osteogenesis of human bone marrow mesenchymal stem cell sheets by microRNA-21-loaded chitosan/hyaluronic acid nanoparticles via reverse transfection

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-05-01

    Full Text Available Zhongshan Wang,1 Guangsheng Wu,2,3 Mengying Wei,4 Qian Liu,1 Jian Zhou,1 Tian Qin,1 Xiaoke Feng,1 Huan Liu,1 Zhihong Feng,1 Yimin Zhao1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, 2State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an, 3Qingdao First Sanatorium, Jinan Military Region, Qingdao, Shandong Province, 4Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi’an, People’s Republic of China Abstract: Cell sheet engineering has emerged as a novel approach to effectively deliver seeding cells for tissue regeneration, and developing human bone marrow mesenchymal stem cell (hBMMSC sheets with high osteogenic ability is a constant requirement from clinics for faster and higher-quality bone formation. In this work, we fabricated biocompatible and safe chitosan (CS/hyaluronic acid (HA nanoparticles (NPs to deliver microRNA-21 (miR-21, which has been proved to accelerate osteogenesis in hBMMSCs; then, the CS/HA/miR-21 NPs were cross-linked onto the surfaces of culture plates with 0.2% gel solution to fabricate miR-21-functionalized culture plates for reverse transfection. hBMMSC sheets were induced continuously for 14 days using a vitamin C-rich method on the miR-21-functionalized culture plates. For the characterization of CS/HA/miR-21 NPs, the particle size, zeta potential, surface morphology, and gel retardation were sequentially investigated. Then, the biological effects of hBMMSC sheets on the miR-21-functionalized culture plates were evaluated. The assay results demonstrated that the hBMMSC sheets could be successfully induced via the novel

  12. Skeletal tissue engineering using embryonic stem cells

    NARCIS (Netherlands)

    Jukes, Jojanneke Maria

    2009-01-01

    Tissue engineering aims at repairing or replacing damaged or diseased tissue. In this thesis, we investigated the potential of embryonic stem cells (ESCs) for cartilage tissue engineering. After differentiation of mouse and human ESCs into the chondrogenic and osteogenic lineage had been established

  13. Autologous preconditioned mesenchymal stem cell sheets improve left ventricular function in a rabbit old myocardial infarction model

    Science.gov (United States)

    Tanaka, Yuya; Shirasawa, Bungo; Takeuchi, Yuriko; Kawamura, Daichi; Nakamura, Tamami; Samura, Makoto; Nishimoto, Arata; Ueno, Koji; Morikage, Noriyasu; Hosoyama, Tohru; Hamano, Kimikazu

    2016-01-01

    Mesenchymal stem cells (MSCs) constitute one of the most powerful tools for therapeutic angiogenesis in infarcted hearts. However, conventional MSC transplantation approaches result in insufficient therapeutic effects due to poor retention of graft cells in severe ischemic diseases. Cell sheet technology has been developed as a new method to prolong graft cell retention even in ischemic tissue. Recently, we demonstrated that hypoxic pretreatment enhances the therapeutic efficacy of cell sheet implantation in infarcted mouse hearts. In this study, we investigated whether hypoxic pretreatment activates the therapeutic functions of bone marrow-derived MSC (BM-MSC) sheets and improves cardiac function in rabbit infarcted hearts following autologous transplantation. Production of vascular endothelial growth factor (VEGF) was increased in BM-MSC monolayer sheets and it peaked at 48 h under hypoxic culture conditions (2% O2). To examine in vivo effects, preconditioned autologous BM-MSC sheets were implanted into a rabbit old myocardial infarction model. Implantation of preconditioned BM-MSC sheets accelerated angiogenesis in the peri-infarcted area and decreased the infarcted area, leading to improvement of the left ventricular function of the infarcted heart. Importantly, the therapeutic efficacy of the preconditioned BM-MSC sheets was higher than that of standardly cultured sheets. Thus, implantation of autologous preconditioned BM-MSC sheets is a feasible approach for enhancing therapeutic angiogenesis in chronically infarcted hearts. PMID:27347329

  14. Hyaluronic acid concentration-mediated changes in structure and function of porous carriers for corneal endothelial cell sheet delivery.

    Science.gov (United States)

    Lai, Jui-Yang

    2016-02-01

    In this study, the effects of hyaluronic acid (HA) concentrations (0.05-1.25wt.%) on the properties of porous carriers for corneal endothelial tissue engineering were investigated. The pore size and porosity gradually increased with decreasing solid content. However, at relatively low HA concentration (i.e., 0.05wt.%), the material samples contained small interior pores and a dense surface skin layer, probably due to no gas bubble effect on the stirring processing of porous microstructures of freeze-dried polysaccharide hydrogels. The carriers prepared from 0.25wt.% HA solution had the highest freezable water content and oxygen and glucose permeability among the samples evaluated. Results of cell viability assays and quantitative real-time reverse transcription polymerase chain reaction analyses showed that the HA concentration-related alteration of porous microstructure dictates the compatibility of biopolymer carriers with corneal endothelial cell (CEC) cultures. In vivo studies demonstrated that the CEC sheet/HA carrier construct implants are therapeutically efficacious in the reconstruction of endothelial scrape-wounded corneas. It is concluded that the polysaccharide concentration is the major factor for affecting the processing of carriers and their structure and function. Porous hydrogels prepared from 0.25wt.% HA solution are capable of delivering bioengineered CEC sheets to the posterior surface of cornea.

  15. Engineering biomolecular microenvironments for cell instructive biomaterials.

    Science.gov (United States)

    Custódio, Catarina A; Reis, Rui L; Mano, João F

    2014-06-01

    Engineered cell instructive microenvironments with the ability to stimulate specific cellular responses are a topic of high interest in the fabrication and development of biomaterials for application in tissue engineering. Cells are inherently sensitive to the in vivo microenvironment that is often designed as the cell "niche." The cell "niche" comprising the extracellular matrix and adjacent cells, influences not only cell architecture and mechanics, but also cell polarity and function. Extensive research has been performed to establish new tools to fabricate biomimetic advanced materials for tissue engineering that incorporate structural, mechanical, and biochemical signals that interact with cells in a controlled manner and to recapitulate the in vivo dynamic microenvironment. Bioactive tunable microenvironments using micro and nanofabrication have been successfully developed and proven to be extremely powerful to control intracellular signaling and cell function. This Review is focused in the assortment of biochemical signals that have been explored to fabricate bioactive cell microenvironments and the main technologies and chemical strategies to encode them in engineered biomaterials with biological information.

  16. A silicon sheet casting experiment. [for solar cell water production

    Science.gov (United States)

    Bickler, D. B.; Sanchez, L. E.; Sampson, W. J.

    1980-01-01

    The casting of silicon blanks for solar cells directly without slicing is an exciting concept. An experiment was performed to investigate the feasibility of developing a machine that casts wafers directly. A Czochralski furnace was modified to accept a graphite ingot-simulating fixture. Silicon was melted in the middle of the ingot simulator in a boron nitride mold. Sample castings showed reasonable crystal size. Solar cells were made from the cast blanks. The performance is reported.

  17. Application of Stem Cells in Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Stem cells have become an important source of seed cells for tissue engineering because they are relatively easy to expand in vitro and can be induced to differentiate into various cell types in vitro or in vivo. In the current stage, most stem cell researches focus on in vitro studies, including in vitro induction and phenotype characterization. Our center has made a great deal of effort in the in vivo study by using stem cells as seed cells for tissue construction. We have used bone marrow stem cells (BMS...

  18. Stem Cells and Tissue Engineering

    CERN Document Server

    Pavlovic, Mirjana

    2013-01-01

    Stem cells are the building blocks for all other cells in an organism. The human body has about 200 different types of cells and any of those cells can be produced by a stem cell. This fact emphasizes the significance of stem cells in transplantational medicine, regenerative therapy and bioengineering. Whether embryonic or adult, these cells can be used for the successful treatment of a wide range of diseases that were not treatable before, such as osteogenesis imperfecta in children, different forms of leukemias, acute myocardial infarction, some neural damages and diseases, etc. Bioengineering, e.g. successful manipulation of these cells with multipotential capacity of differentiation toward appropriate patterns and precise quantity, are the prerequisites for successful outcome and treatment. By combining in vivo and in vitro techniques, it is now possible to manage the wide spectrum of tissue damages and organ diseases. Although the stem-cell therapy is not a response to all the questions, it provides more...

  19. Nanomaterials for Engineering Stem Cell Responses.

    Science.gov (United States)

    Kerativitayanan, Punyavee; Carrow, James K; Gaharwar, Akhilesh K

    2015-08-05

    Recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. Synergistic interactions between nanomaterials and stem cell engineering offer numerous possibilities to address some of the daunting challenges in regenerative medicine, such as controlling trigger differentiation, immune reactions, limited supply of stem cells, and engineering complex tissue structures. Specifically, the interactions between stem cells and their microenvironment play key roles in controlling stem cell fate, which underlines therapeutic success. However, the interactions between nanomaterials and stem cells are not well understood, and the effects of the nanomaterials shape, surface morphology, and chemical functionality on cellular processes need critical evaluation. In this Review, focus is put on recent development in nanomaterial-stem cell interactions, with specific emphasis on their application in regenerative medicine. Further, the emerging technologies based on nanomaterials developed over the past decade for stem cell engineering are reviewed, as well as the potential applications of these nanomaterials in tissue regeneration, stem cell isolation, and drug/gene delivery. It is anticipated that the enhanced understanding of nanomaterial-stem cell interactions will facilitate improved biomaterial design for a range of biomedical and biotechnological applications.

  20. [Stem cells and tissue engineering techniques].

    Science.gov (United States)

    Sica, Gigliola

    2013-01-01

    The therapeutic use of stem cells and tissue engineering techniques are emerging in urology. Here, stem cell types, their differentiating potential and fundamental characteristics are illustrated. The cancer stem cell hypothesis is reported with reference to the role played by stem cells in the origin, development and progression of neoplastic lesions. In addition, recent reports of results obtained with stem cells alone or seeded in scaffolds to overcome problems of damaged urinary tract tissue are summarized. Among others, the application of these biotechnologies in urinary bladder, and urethra are delineated. Nevertheless, apart from the ethical concerns raised from the use of embryonic stem cells, a lot of questions need to be solved concerning the biology of stem cells before their widespread use in clinical trials. Further investigation is also required in tissue engineering utilizing animal models.

  1. Stem Cell-Based Dental Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Petar Zivkovic

    2010-01-01

    Full Text Available The development of biological and biomaterial sciences profiled tissue engineering as a new and powerful tool for biological replacement of organs. The combination of stem cells and suitable scaffolds is widely used in experiments today, in order to achieve partial or whole organ regeneration. This review focuses on the use of tissue engineering strategies in tooth regeneration, using stem cells and stem cells/scaffold constructs. Although whole tooth regeneration is still not possible, there are promising results. However, to achieve this goal, it is important to understand and further explore the mechanisms underlying tooth development. Only then will we be able to mimic the natural processes with the use of stem cells and tissue engineering techniques.

  2. Engineered cell-cell communication via DNA messaging

    Directory of Open Access Journals (Sweden)

    Ortiz Monica E

    2012-09-01

    Full Text Available Abstract Background Evolution has selected for organisms that benefit from genetically encoded cell-cell communication. Engineers have begun to repurpose elements of natural communication systems to realize programmed pattern formation and coordinate other population-level behaviors. However, existing engineered systems rely on system-specific small molecules to send molecular messages among cells. Thus, the information transmission capacity of current engineered biological communication systems is physically limited by specific biomolecules that are capable of sending only a single message, typically “regulate transcription.” Results We have engineered a cell-cell communication platform using bacteriophage M13 gene products to autonomously package and deliver heterologous DNA messages of varying lengths and encoded functions. We demonstrate the decoupling of messages from a common communication channel via the autonomous transmission of various arbitrary genetic messages. Further, we increase the range of engineered DNA messaging across semisolid media by linking message transmission or receipt to active cellular chemotaxis. Conclusions We demonstrate decoupling of a communication channel from message transmission within engineered biological systems via the autonomous targeted transduction of user-specified heterologous DNA messages. We also demonstrate that bacteriophage M13 particle production and message transduction occurs among chemotactic bacteria. We use chemotaxis to improve the range of DNA messaging, increasing both transmission distance and communication bit rates relative to existing small molecule-based communication systems. We postulate that integration of different engineered cell-cell communication platforms will allow for more complex spatial programming of dynamic cellular consortia.

  3. A global assessment of stem cell engineering.

    Science.gov (United States)

    Loring, Jeanne F; McDevitt, Todd C; Palecek, Sean P; Schaffer, David V; Zandstra, Peter W; Nerem, Robert M

    2014-10-01

    Over the last 2 years a global assessment of stem cell engineering (SCE) was conducted with the sponsorship of the National Science Foundation, the National Cancer Institute at the National Institutes of Health, and the National Institute of Standards and Technology. The purpose was to gather information on the worldwide status and trends in SCE, that is, the involvement of engineers and engineering approaches in the stem cell field, both in basic research and in the translation of research into clinical applications and commercial products. The study was facilitated and managed by the World Technology Evaluation Center. The process involved site visits in both Asia and Europe, and it also included several different workshops. From this assessment, the panel concluded that there needs to be an increased role for engineers and the engineering approach. This will provide a foundation for the generation of new markets and future economic growth. To do this will require an increased investment in engineering, applied research, and commercialization as it relates to stem cell research and technology. It also will require programs that support interdisciplinary teams, new innovative mechanisms for academic-industry partnerships, and unique translational models. In addition, the global community would benefit from forming strategic partnerships between countries that can leverage existing and emerging strengths in different institutions. To implement such partnerships will require multinational grant programs with appropriate review mechanisms.

  4. A surgical robot with a heart-surface-motion synchronization mechanism for myoblast cell sheet transplantation.

    Science.gov (United States)

    Xu, Kangyi; Nakamura, Ryoichi

    2013-01-01

    Myoblast cell sheets are employed in the clinical treatment of heart disorders. We propose a surgical robot system with two endoscopic cameras, characterized by a double remote center of motion (RCM) mechanism, to realize heart-surface-motion synchronization movement for myoblast cell sheet transplantation on a beating heart surface. A robot system with the double RCM mechanism was developed for which the linear and rotation motions are totally isolated, and an experiment was conducted to evaluate the tracking accuracy of the robot system when tracking a randomly moving target. The tracking data were updated with a Polaris system at 30 Hz. The experiment results showed linear and rotation tracking errors of 4.93 ± 5.92 mm and 2.54 ± 5.44°, respectively.

  5. SUBSTRATE MATERIALS FOR POLY-CSiTF SOLAR CELLS:OPTIMIZATION OF SILICON SHEET FROM POWDER

    Institute of Scientific and Technical Information of China (English)

    Q. Ban; H. Shen; X.J. Wang; X.W. Zou; Z.C. Liang

    2005-01-01

    The optimization of silicon sheet from powder (SSP) technology as polycrystalline silicon thin film (poly-CSiTF) solar cells' substrate materials is studied by orthogonal design experimental method. Based on technological optimization of SSP prepared from electronic grade silicon powder, SSP solar cell devices with simple structure are prepared and the effect of SSP substrate is discussed. Up to now, the conversion efficiency of the prepared solar cells on low purity SSP substrate with fundamental structure has reached 8.25% (with area of 1 cm×1 cm).

  6. Atomic step-and-terrace surface of polyimide sheet for advanced polymer substrate engineering

    Science.gov (United States)

    Tan, G.; Shimada, K.; Nozawa, Y.; Kaneko, S.; Urakami, T.; Koyama, K.; Komura, M.; Matsuda, A.; Yoshimoto, M.

    2016-07-01

    Typical thermostable and flexible polyimide polymers exhibit many excellent properties such as strong mechanical and chemical resistance. However, in contrast to single-crystal substrates like silicon or sapphire, polymers mostly display disordered and rough surfaces, which may result in instability and degradation of the interfaces between thin films and polymer substrates. As a step toward the development of next-generation polymer substrates, we here report single-atom-layer imprinting onto the polyimide sheets, resulting in an ultrasmooth 0.3 nm high atomic step-and-terrace surface on the polyimides. The ultrasmooth polymer substrates are expected to be applied to the fabrication of nanostructures such as superlattices, nanowires, or quantum dots in nanoscale-controlled electronic devices. We fabricate smooth and atomically stepped indium tin oxide transparent conducting oxide thin films on the imprinted polyimide sheets for future use in organic-based optoelectronic devices processed with nanoscale precision. Furthermore, toward 2D polymer substrate nanoengineering, we demonstrate nanoscale letter writing on the atomic step-and-terrace polyimide surface via atomic force microscopy probe scratching.

  7. Study of Photovoltaic Cells Engineering Mathematical Model

    Science.gov (United States)

    Zhou, Jun; Yu, Zhengping; Lu, Zhengyi; Li, Chenhui; Zhang, Ruilan

    2016-11-01

    The characteristic curve of photovoltaic cells is the theoretical basis of PV Power, which simplifies the existing mathematical model, eventually, obtains a mathematical model used in engineering. The characteristic curve of photovoltaic cells contains both exponential and logarithmic calculation. The exponential and logarithmic spread out through Taylor series, which includes only four arithmetic and use single chip microcontroller as the control center. The result shows that: the use of single chip microcontroller for calculating exponential and logarithmic functions, simplifies mathematical model of PV curve, also can meet the specific conditions’ requirement for engineering applications.

  8. 工程化肝组织肝表面片状植入新方法%New method of liver mrface sheet implantation with engineering Liver tissue

    Institute of Scientific and Technical Information of China (English)

    刘巨超; 周海洋; 孙慧伟; 丁毅; 徐迎新

    2012-01-01

    Objective To explore the feasibility of orthotopic.ally implanting larger-size,sheet-likeengineered liver tissue on the surface of liver to facilitate the establishment of blood supply.MethodsHepatocytes and microvessel endothelial cells isolated from newborn rats using enzymatic dissociation withtypsin and by tissue adherence method,respectively,were combined with sheet-like collagen scaffold andvascular endothelial growth factor (VEGF,10 g/L) to generate bepatocytes/endotheliocytes/VEGF/colla-gen constructs.The constructs were then implanted onto the surface of 15 rats' livers through the adherencemethod of sheet-like engineered liver tissue.Gross and histological observation was taken four weeks afterimplantation.Results The viability of both hepatocytes and endotheliocytes was over 90%.Sheet engi-neering liver tissue can fit closely with the orthotopic liver by the liver surface pasting method,and formhepatocyte-like tissue which was larger than 1 cm3.Hematoxylin and eosin (HE) staining showed that thehepatocytes were in good condition and distributed evenly in the implants,and angiogenesis could also beseen.We didn' t find cell degeneration and death.Conclusion The liver surface pasting method is sim-ple and safe,which can be used to build larger size of the engineering liver tissue,and also expected toreach the purpose of repairing damaged liver in situ.%目的 探索较大尺度工程化肝组织原位肝表面贴覆片状植入、尽快建立血供的可行性.方法 将采用胰酶冷消化法分离的新生大鼠肝细胞(1×1010个/L)、肺组织块贴壁法分离的大鼠微血管内皮细胞(1 ×1010个/L),与片状胶原支架、血管内皮生长因子(VEGF,10g/L)复合构建肝细胞/内皮细胞/血管生长因子/胶原支架复合的片状工程化肝组织.将其在15只大鼠肝表面贴覆植入,4周后取样进行大体观察及组织切片苏木素-伊红(HE)染色.结果 分离的肝细胞及内皮细胞活率均为90%以上.片状工

  9. Nanotechnology, Cell Culture and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Kazutoshi Haraguchi

    2011-01-01

    Full Text Available We have fabricated new types of polymer hydrogels and polymer nanocomposites, i.e., nanocomposite gels (NC gels and soft, polymer nanocomposites (M-NCs: solid, with novel organic/inorganic network structures. Both NC gels and M-NCs were synthesized by in-situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms such as film, sheet, tube, coating, etc. and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles act as multi-functional crosslinkers to form new types of network systems. Both NC gels and M-NCs have extraordinary optical and mechanical properties including ultra-high reversible extensibility, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micro-patterning, etc. For examples, the biological testing of medical devices, comprised of a sensitization test, an irritation test, an intracutaneous test and an in vitro cytotoxicity test,was carried out for NC gels and M-NCs. The safety of NC gels and M-NCs was confirmed in all tests. Also, the interaction of living tissue with NC gel was investigated in vivo by implantation in live goats; neither inflammation nor concrescence occurred around the NC gels. Furthermore, it was found that both N-NC gels consisting of poly(N-isopropylacrylamide(PNIPA/clay network and M-NCs consisting of poly(2-methoxyethyacrylate(PMEA/clay network show characteristic cell culture and subsequent cell detachment on their surfaces, although it was almost impossible to culture cells on conventional, chemically-crosslinked PNIPA hydrogels and chemically crossslinked PMEA, regardless of their crosslinker concentration. Various kinds of cells, such ashumanhepatoma cells (HepG2, normal human dermal fibroblast (NHDF, and human umbilical vein endothelial cells (HUVEC, could be cultured to be confluent on the surfaces of N

  10. Thermo-responsive methylcellulose hydrogels as temporary substrate for cell sheet biofabrication.

    Science.gov (United States)

    Altomare, Lina; Cochis, Andrea; Carletta, Andrea; Rimondini, Lia; Farè, Silvia

    2016-05-01

    Methylcellulose (MC), a water-soluble polymer derived from cellulose, was investigated as a possible temporary substrate having thermo-responsive properties favorable for cell culturing. MC-based hydrogels were prepared by a dispersion technique, mixing MC powder (2, 4, 6, 8, 10, 12 % w/v) with selected salts (sodium sulphate, Na2SO4), sodium phosphate, calcium chloride, or phosphate buffered saline, to evaluate the influence of different compositions on the thermo-responsive behavior. The inversion test was used to determine the gelation temperatures of the different hydrogel compositions; thermo-mechanical properties and thermo-reversibility of the MC hydrogels were investigated by rheological analysis. Gelation temperatures and rheological behavior depended on the MC concentration and type and concentration of salt used in hydrogel preparation. In vitro cytotoxicity tests, performed using L929 mouse fibroblasts, showed no toxic release from all the tested hydrogels. Among the investigated compositions, the hydrogel composed of 8 % w/v MC with 0.05 M Na2SO4 had a thermo-reversibility temperature at 37 °C. For that reason, this formulation was thus considered to verify the possibility of inducing in vitro spontaneous detachment of cells previously seeded on the hydrogel surface. A continuous cell layer (cell sheet) was allowed to grow and then detached from the hydrogel surface without the use of enzymes, thanks to the thermo-responsive behavior of the MC hydrogel. Immunofluorescence observation confirmed that the detached cell sheet was composed of closely interacting cells.

  11. Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution.

    Science.gov (United States)

    Meddens, Marjolein B M; Liu, Sheng; Finnegan, Patrick S; Edwards, Thayne L; James, Conrad D; Lidke, Keith A

    2016-06-01

    We have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single molecule super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet.

  12. Genetic engineering with T cell receptors.

    Science.gov (United States)

    Zhang, Ling; Morgan, Richard A

    2012-06-01

    In the past two decades, human gene transfer research has been translated from a laboratory technology to clinical evaluation. The success of adoptive transfer of tumor-reactive lymphocytes to treat the patients with metastatic melanoma has led to new strategies to redirect normal T cells to recognize tumor antigens by genetic engineering with tumor antigen-specific T cell receptor (TCR) genes. This new strategy can generate large numbers of defined antigen-specific cells for therapeutic application. Much progress has been made to TCR gene transfer systems by optimizing gene expression and gene transfer protocols. Vector and protein modifications have enabled excellent expression of introduced TCR chains in human lymphocytes with reduced mis-pairing between the introduced and endogenous TCR chains. Initial clinical studies have demonstrated that TCR gene-engineered T cells could mediate tumor regression in vivo. In this review, we discuss the progress and prospects of TCR gene-engineered T cells as a therapeutic strategy for treating patients with melanoma and other cancers.

  13. Engineering the niche for stem cells.

    Science.gov (United States)

    Tan, Shawna; Barker, Nicholas

    2013-12-01

    Much has been made about the potential for stem cells in regenerative medicine but the reality is that the development of actual therapies has been slow. Adult stem cells rely heavily on the assortment of biochemical and biophysical elements that constitute the local microenvironment in which they exist. One goal of biomedicine is to create an artificial yet biofunctional niche to support multipotency, differentiation and proliferation. Such tools would facilitate more conclusive experimentation by biologists, pharmaceutical scientists and tissue engineers. While many bioengineering techniques and platforms are already in use, technological innovations now allow this to be done at a higher resolution and specificity. Ultimately, the multidisciplinary integration of engineering and biology will allow the niche to be generated at a scale that can be clinically exploited. Using the systems that constitute the intestinal, hematopoietic and epidermal tissues, this article summarizes the various approaches and tools currently employed to recreate stem cell niches and also explores recent advances in the field.

  14. Materials Comparison of Cutting Tools Functional Parts for Cutting of Electrical Engineering Sheets

    Directory of Open Access Journals (Sweden)

    Jan ZLÁMALÍK

    2012-06-01

    Full Text Available Paper concerns the comparison of functional materials parts of cutting tools used for the production of stator and rotor sheets in the electrical industry from point of view of their life. Alternatives and the properties of metal used for the production of stator and rotor components in electrical rotating machines are analysed. The main factors affecting the life of cutting tools of functional parts are analysed, one of the most important is the cutting tool functional parts material itself. Comparison of three variants of the cuttong tool funkcional parts material – 19 436 tool steel (chrome steel according to the Czech State Standard 41 9436, 19 830 high speed steel according to the Czech State Standard 41 9830 and a special powder metallurgy product – ledeburite tool steel Vanadis 10. Useful lifes of the functional components of individual cutting tools performances can be calculated from the theoretical lifes by their multiplying the coefficients of the tool design and the cutting edges shape complexity.

  15. Engineered Models of Confined Cell Migration

    Science.gov (United States)

    Paul, Colin D.; Hung, Wei-Chien; Wirtz, Denis; Konstantopoulos, Konstantinos

    2017-01-01

    Cells in the body are physically confined by neighboring cells, tissues, and the extracellular matrix. Although physical confinement modulates intracellular signaling and the underlying mechanisms of cell migration, it is difficult to study in vivo. Furthermore, traditional two-dimensional cell migration assays do not recapitulate the complex topographies found in the body. Therefore, a number of experimental in vitro models that confine and impose forces on cells in well-defined microenvironments have been engineered. We describe the design and use of microfluidic microchannel devices, grooved substrates, micropatterned lines, vertical confinement devices, patterned hydrogels, and micropipette aspiration assays for studying cell responses to confinement. Use of these devices has enabled the delineation of changes in cytoskeletal reorganization, cell–substrate adhesions, intracellular signaling, nuclear shape, and gene expression that result from physical confinement. These assays and the physiologically relevant signaling pathways that have been elucidated are beginning to have a translational and clinical impact. PMID:27420571

  16. Epithelial sheet folding induces lumen formation by Madin-Darby canine kidney cells in a collagen gel.

    Directory of Open Access Journals (Sweden)

    Sumire Ishida

    Full Text Available Lumen formation is important for morphogenesis; however, an unanswered question is whether it involves the collective migration of epithelial cells. Here, using a collagen gel overlay culture method, we show that Madin-Darby canine kidney cells migrated collectively and formed a luminal structure in a collagen gel. Immediately after the collagen gel overlay, an epithelial sheet folded from the periphery, migrated inwardly, and formed a luminal structure. The inhibition of integrin-β1 or Rac1 activity decreased the migration rate of the peripheral cells after the sheets folded. Moreover, lumen formation was perturbed by disruption of apical-basolateral polarity induced by transforming growth factor-β1. These results indicate that cell migration and cell polarity play an important role in folding. To further explore epithelial sheet folding, we developed a computer-simulated mechanical model based on the rigidity of the extracellular matrix. It indicated a soft substrate is required for the folding movement.

  17. Cell-Derived Extracellular Matrix: Basic Characteristics and Current Applications in Orthopedic Tissue Engineering.

    Science.gov (United States)

    Zhang, Weixiang; Zhu, Yun; Li, Jia; Guo, Quanyi; Peng, Jiang; Liu, Shichen; Yang, Jianhua; Wang, Yu

    2016-06-01

    The extracellular matrix (ECM) is a dynamic and intricate microenvironment with excellent biophysical, biomechanical, and biochemical properties, which can directly or indirectly regulate cell proliferation, adhesion, migration, and differentiation, as well as plays key roles in homeostasis and regeneration of tissues and organs. The ECM has attracted a great deal of attention with the rapid development of tissue engineering in the field of regenerative medicine. Tissue-derived ECM scaffolds (also referred to as decellularized tissues and whole organs) are considered a promising therapy for the repair of musculoskeletal defects, including those that are widely used in orthopedics, although there are a few shortcomings. Similar to tissue-derived ECM scaffolds, cell-derived ECM scaffolds also have highly advantageous biophysical and biochemical properties, in particular their ability to be produced in vitro from a number of different cell types. Furthermore, cell-derived ECM scaffolds more closely resemble native ECM microenvironments. The products of cell-derived ECM have a wide range of biomedical applications; these include reagents for cell culture substrates and biomaterials for scaffolds, hybrid scaffolds, and living cell sheet coculture systems. Although cell-derived ECM has only just begun to be investigated, it has great potential as a novel approach for cell-based tissue repair in orthopedic tissue engineering. This review summarizes and analyzes the various types of cell-derived ECM products applied in cartilage, bone, and nerve tissue engineering in vitro or in vivo and discusses future directions for investigation of cell-derived ECM.

  18. TOPICAL REVIEW: Stem cells engineering for cell-based therapy

    Science.gov (United States)

    Taupin, Philippe

    2007-09-01

    Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

  19. Cartilage Engineering from Mesenchymal Stem Cells

    Science.gov (United States)

    Goepfert, C.; Slobodianski, A.; Schilling, A. F.; Adamietz, P.; Pörtner, R.

    Mesenchymal progenitor cells known as multipotent mesenchymal stromal cells or mesenchymal stem cells (MSC) have been isolated from various tissues. Since they are able to differentiate along the mesenchymal lineages of cartilage and bone, they are regarded as promising sources for the treatment of skeletal defects. Tissue regeneration in the adult organism and in vitro engineering of tissues is hypothesized to follow the principles of embryogenesis. The embryonic development of the skeleton has been studied extensively with respect to the regulatory mechanisms governing morphogenesis, differentiation, and tissue formation. Various concepts have been designed for engineering tissues in vitro based on these developmental principles, most of them involving regulatory molecules such as growth factors or cytokines known to be the key regulators in developmental processes. Growth factors most commonly used for in vitro cultivation of cartilage tissue belong to the fibroblast growth factor (FGF) family, the transforming growth factor-beta (TGF-β) super-family, and the insulin-like growth factor (IGF) family. In this chapter, in vivo actions of members of these growth factors described in the literature are compared with in vitro concepts of cartilage engineering making use of these growth factors.

  20. Cell engineering and molecular pharming for biopharmaceuticals.

    Science.gov (United States)

    Abdullah, M A; Rahmah, Anisa Ur; Sinskey, A J; Rha, C K

    2008-05-14

    Biopharmaceuticals are often produced by recombinant E. coli or mammalian cell lines. This is usually achieved by the introduction of a gene or cDNA coding for the protein of interest into a well-characterized strain of producer cells. Naturally, each recombinant production system has its own unique advantages and disadvantages. This paper examines the current practices, developments, and future trends in the production of biopharmaceuticals. Platform technologies for rapid screening and analyses of biosystems are reviewed. Strategies to improve productivity via metabolic and integrated engineering are also highlighted.

  1. Cell Engineering and Molecular Pharming for Biopharmaceuticals

    Science.gov (United States)

    Abdullah, M.A; Rahmah, Anisa ur; Sinskey, A.J; Rha, C.K

    2008-01-01

    Biopharmaceuticals are often produced by recombinant E. coli or mammalian cell lines. This is usually achieved by the introduction of a gene or cDNA coding for the protein of interest into a well-characterized strain of producer cells. Naturally, each recombinant production system has its own unique advantages and disadvantages. This paper examines the current practices, developments, and future trends in the production of biopharmaceuticals. Platform technologies for rapid screening and analyses of biosystems are reviewed. Strategies to improve productivity via metabolic and integrated engineering are also highlighted. PMID:19662143

  2. Cell sheets image validation of phase-diversity homodyne OCT and effect of the light irradiation on cells

    Science.gov (United States)

    Senda, Naoko; Osawa, Kentaro

    2016-04-01

    Optical coherence tomography (OCT) is one of powerful 3D tissue imaging tools with no fluorescence staining. We have reported that Phase-Diversity Homodyne OCT developed in Hitachi could be useful for non-invasive regeneration tissue evaluation test. The OCT enables cell imaging because of high resolution (axial resolution; ~2.6 μm, lateral resolution; ~1 μm, in the air), whereas conventional OCT was not used for cell imaging because of low resolution (10~20 μm). Furthermore, the OCT has advantage over other 3D imaging devices in cost because the light source and the objective were originally used as an optical pickup of compact disc. In this report, we aimed to assess effectiveness and safety of Phase-Diversity Homodyne OCT cell imaging. Effectiveness of OCT was evaluated by imaging a living cell sheet of human oral mucosal epithelial cells. OCT images were compared with reflection confocal microscopy (RCM) images, because confocal optical system is the highest resolution (<1 μm) 3D in vivo imaging technique. Similar nuclei images were confirmed with OCT and RCM, which suggested the OCT has enough resolution to image nuclei inside a cell sheet. Degree of differentiation could be estimated using OCT images, which becomes possible because the size of cells depends on distribution of differentiation. Effect of the OCT light irradiation on cells was studied using NIH/3T3 cells. Light irradiation, the exposure amount of which is equivalent to OCT, had no impact on cell shape, cell viability, and proliferation rate. It suggested that the light irradiation has no cell damage under the condition.

  3. Effect of Sheet Resistance and Morphology of ITO Thin Films on Polymer Solar Cell Characteristics

    Directory of Open Access Journals (Sweden)

    Ram Narayan Chauhan

    2012-01-01

    Full Text Available Solar cell fabrication on flexible thin plastic sheets needs deposition of transparent conducting anode layers at low temperatures. ITO thin films are deposited on glass by RF sputtering at substrate temperature of 70∘C and compare their phase, morphology, optical, and electrical properties with commercial ITO. The films contain smaller nanocrystallites in (222 preferred orientation and exhibit comparable optical transmittance (~95% in the wavelength range of 550–650 nm, but high sheet resistance of ~103 Ω/□ (the value being ~36 Ω/□ for commercial ITO.The polymer solar cells with PEDOT: PSS and P3HT: PCBM layers realized on RF sputtered vis-a-vis commercial ITO thin films are shown to display a marginal difference in power conversion efficiency, low fill factor, and low open-circuit voltage but increased short-circuit current density. The decrease in fill factor, open-circuit voltage is compensated by increased short-circuit current. Detailed study is made of increased short-circuit current density.

  4. Engineered Trehalose Permeable to Mammalian Cells.

    Directory of Open Access Journals (Sweden)

    Alireza Abazari

    Full Text Available Trehalose is a naturally occurring disaccharide which is associated with extraordinary stress-tolerance capacity in certain species of unicellular and multicellular organisms. In mammalian cells, presence of intra- and extracellular trehalose has been shown to confer improved tolerance against freezing and desiccation. Since mammalian cells do not synthesize nor import trehalose, the development of novel methods for efficient intracellular delivery of trehalose has been an ongoing investigation. Herein, we studied the membrane permeability of engineered lipophilic derivatives of trehalose. Trehalose conjugated with 6 acetyl groups (trehalose hexaacetate or 6-O-Ac-Tre demonstrated superior permeability in rat hepatocytes compared with regular trehalose, trehalose diacetate (2-O-Ac-Tre and trehalose tetraacetate (4-O-Ac-Tre. Once in the cell, intracellular esterases hydrolyzed the 6-O-Ac-Tre molecules, releasing free trehalose into the cytoplasm. The total concentration of intracellular trehalose (plus acetylated variants reached as high as 10 fold the extracellular concentration of 6-O-Ac-Tre, attaining concentrations suitable for applications in biopreservation. To describe this accumulation phenomenon, a diffusion-reaction model was proposed and the permeability and reaction kinetics of 6-O-Ac-Tre were determined by fitting to experimental data. Further studies suggested that the impact of the loading and the presence of intracellular trehalose on cellular viability and function were negligible. Engineering of trehalose chemical structure rather than manipulating the cell, is an innocuous, cell-friendly method for trehalose delivery, with demonstrated potential for trehalose loading in different types of cells and cell lines, and can facilitate the wide-spread application of trehalose as an intracellular protective agent in biopreservation studies.

  5. Periodontal regeneration in swine after cell injection and cell sheet transplantation of human dental pulp stem cells following good manufacturing practice

    OpenAIRE

    2016-01-01

    Background Periodontitis, one of the most prevalent infectious diseases in humans, results in the destruction of tooth-supporting tissues. The purpose of the present study is to evaluate the effect of cell injection and cell sheet transplantation on periodontal regeneration in a swine model. Methods In the present study, human dental pulp stem cells (hDPSCs) were transplanted into a swine model for periodontal regeneration. Twelve miniature pigs were used to generate periodontitis with bone d...

  6. Design, fabrication and application of tissue engineering used cells scaffold

    Institute of Scientific and Technical Information of China (English)

    WANG Shenguo; BEI Jianzhong

    2001-01-01

    @@ FUNCTIONS OF CELLS SCAFFOLD IN THE TISSUE ENGINEERINGCell, cells scaffold and the construction of tissue and organ are three main factors for the Tissue Engineering. A main function of cells scaffold in tissue engineering is to provide an environment for cells propagation.

  7. Strategies for cell engineering in tissue repair.

    Science.gov (United States)

    Brown, R A; Smith, K D; Angus McGrouther, D

    1997-01-01

    Cellular and tissue engineering are new areas of research, currently attracting considerable interest because of the remarkable potential they have for clinical application. Some claims have indeed been dramatic, including the possibility of growing complete, artificial organs, such as the liver. However, amid such long-term aspirations there is the very real possibility that small tissues (artificial grafts) may be fabricated in the near future for use in reconstructive surgery. Logically, we should focus on how it is possible to produce modest, engineered tissues for tissue repair. It is evident that strategies to date either depend on innate information within implanted cells, to reform the target tissue or aim to provide appropriate environmental cues or guidance to direct cell behavior. It is argued here that present knowledge of tissue repair biology points us toward the latter approach, providing external cues which will direct how cells should organize the new tissue. This will be particularly true where we need to reproduce microscopic and ultrastructural features of the original tissue architecture. A number of such cues have been identified, and methods are already available, including substrate chemistry, substrate contact guidance, mechanical loading, and biochemical mediators to provide these cues. Examples of these are already being used with some success to control the formation of tissue structures.

  8. Effect of the compact Ti layer on the efficiency of dye-sensitized solar cells assembled using stainless steel sheets

    Science.gov (United States)

    Meng, Lijian; Wu, Mingxing; Wang, Yongmei; Guo, Wei; Ma, Chunyu; Ma, Tingli; Silva, Rui

    2013-06-01

    Titanium films have been deposited on stainless steel metal sheets using dc magnetron sputtering technique at different substrate temperatures. The structure of the titanium films strongly depend on the substrate temperature. The titanium film deposited at the substrate temperature lower than 300 °C has a loose flat sheet grains structure and the titanium film prepared at the substrate temperature higher than 500 °C has a dense nubby grains structure. The DSSC assembled using stainless steel sheet coated with titanium film deposited at high substrate temperature has a low charge transfer resistance in the TiO2/Ti interface and results in a high conversion efficiency. The DSSC assembled using stainless steel sheet coated with titanium film deposited at temperature higher than 500 °C has higher conversion efficiency than that assembled using titanium metal sheet as the substrate. The maximum conversion efficiency, 2.26% is obtained for DSSC assembled using stainless steel sheet coated with titanium film deposited at 700 °C substrate temperature, which is about 70% of the conversion efficiency of the FTO reference cell used in this study.

  9. Stem Cells in Functional Bladder Engineering

    Science.gov (United States)

    Smolar, Jakub; Salemi, Souzan; Horst, Maya; Sulser, Tullio; Eberli, Daniel

    2016-01-01

    Conditions impairing bladder function in children and adults, such as myelomeningocele, posterior urethral valves, bladder exstrophy or spinal cord injury, often need urinary diversion or augmentation cystoplasty as when untreated they may cause severe bladder dysfunction and kidney failure. Currently, the gold standard therapy of end-stage bladder disease refractory to conservative management is enterocystoplasty, a surgical enlargement of the bladder with intestinal tissue. Despite providing functional improvement, enterocystoplasty is associated with significant long-term complications, such as recurrent urinary tract infections, metabolic abnormalities, stone formation, and malignancies. Therefore, there is a strong clinical need for alternative therapies for these reconstructive procedures, of which stem cell-based tissue engineering (TE) is considered to be the most promising future strategy. This review is focused on the recent progress in bladder stem cell research and therapy and the challenges that remain for the development of a functional bladder wall.

  10. Quantitative neuroanatomy of all Purkinje cells with light sheet microscopy and high-throughput image analysis

    Directory of Open Access Journals (Sweden)

    Ludovico eSilvestri

    2015-05-01

    Full Text Available Characterizing the cytoarchitecture of mammalian central nervous system on a brain-wide scale is becoming a compelling need in neuroscience. For example, realistic modeling of brain activity requires the definition of quantitative features of large neuronal populations in the whole brain. Quantitative anatomical maps will also be crucial to classify the cytoarchtitectonic abnormalities associated with neuronal pathologies in a high reproducible and reliable manner. In this paper, we apply recent advances in optical microscopy and image analysis to characterize the spatial distribution of Purkinje cells across the whole cerebellum. Light sheet microscopy was used to image with micron-scale resolution a fixed and cleared cerebellum of an L7-GFP transgenic mouse, in which all Purkinje cells are fluorescently labeled. A fast and scalable algorithm for fully automated cell identification was applied on the image to extract the position of all the fluorescent Purkinje cells. This vectorized representation of the cell population allows a thorough characterization of the complex three-dimensional distribution of the neurons, highlighting the presence of gaps inside the lamellar organization of Purkinje cells, whose density is believed to play a significant role in autism spectrum disorders. Furthermore, clustering analysis of the localized somata permits dividing the whole cerebellum in groups of Purkinje cells with high spatial correlation, suggesting new possibilities of anatomical partition. The quantitative approach presented here can be extended to study the distribution of different types of cell in many brain regions and across the whole encephalon, providing a robust base for building realistic computational models of the brain, and for unbiased morphological tissue screening in presence of pathologies and/or drug treatments.

  11. Low cost monocrystalline silicon sheet fabrication for solar cells by advanced ingot technology

    Science.gov (United States)

    Fiegl, G. F.; Bonora, A. C.

    1980-01-01

    The continuous liquid feed (CLF) Czochralski furnace and the enhanced I.D. slicing technology for the low-cost production of monocrystalline silicon sheets for solar cells are discussed. The incorporation of the CLF system is shown to improve ingot production rate significantly. As demonstrated in actual runs, higher than average solidification rates (75 to 100 mm/hr for 150 mm 1-0-0 crystals) can be achieved, when the system approaches steady-state conditions. The design characteristics of the CLF furnace are detailed, noting that it is capable of precise control of dopant impurity incorporation in the axial direction of the crystal. The crystal add-on cost is computed to be $11.88/sq m, considering a projected 1986 25-slice per cm conversion factor with an 86% crystal growth yield.

  12. Nano scaffolds and stem cell therapy in liver tissue engineering

    Science.gov (United States)

    Montaser, Laila M.; Fawzy, Sherin M.

    2015-08-01

    Tissue engineering and regenerative medicine have been constantly developing of late due to the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Although stem cells hold great potential for the treatment of many injuries and degenerative diseases, several obstacles must be overcome before their therapeutic application can be realized. These include the development of advanced techniques to understand and control functions of micro environmental signals and novel methods to track and guide transplanted stem cells. A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. The application of nanotechnology to stem cell biology would be able to address those challenges. Combinations of stem cell therapy and nanotechnology in tissue engineering and regenerative medicine have achieved significant advances. These combinations allow nanotechnology to engineer scaffolds with various features to control stem cell fate decisions. Fabrication of Nano fiber cell scaffolds onto which stem cells can adhere and spread, forming a niche-like microenvironment which can guide stem cells to proceed to heal damaged tissues. In this paper, current and emergent approach based on stem cells in the field of liver tissue engineering is presented for specific application. The combination of stem cells and tissue engineering opens new perspectives in tissue regeneration for stem cell therapy because of the potential to control stem cell behavior with the physical and chemical characteristics of the engineered scaffold environment.

  13. Engineered T cells: the promise and challenges of cancer immunotherapy.

    Science.gov (United States)

    Fesnak, Andrew D; June, Carl H; Levine, Bruce L

    2016-08-23

    The immune system evolved to distinguish non-self from self to protect the organism. As cancer is derived from our own cells, immune responses to dysregulated cell growth present a unique challenge. This is compounded by mechanisms of immune evasion and immunosuppression that develop in the tumour microenvironment. The modern genetic toolbox enables the adoptive transfer of engineered T cells to create enhanced anticancer immune functions where natural cancer-specific immune responses have failed. Genetically engineered T cells, so-called 'living drugs', represent a new paradigm in anticancer therapy. Recent clinical trials using T cells engineered to express chimeric antigen receptors (CARs) or engineered T cell receptors (TCRs) have produced stunning results in patients with relapsed or refractory haematological malignancies. In this Review we describe some of the most recent and promising advances in engineered T cell therapy with a particular emphasis on what the next generation of T cell therapy is likely to entail.

  14. Characterization of Tensile Mechanical Behavior of MSCs/PLCL Hybrid Layered Sheet

    Directory of Open Access Journals (Sweden)

    Azizah Intan Pangesty

    2016-06-01

    Full Text Available A layered construct was developed by combining a porous polymer sheet and a cell sheet as a tissue engineered vascular patch. The primary objective of this study is to investigate the influence of mesenchymal stem cells (MSCs sheet on the tensile mechanical properties of porous poly-(l-lactide-co-ε-caprolactone (PLCL sheet. The porous PLCL sheet was fabricated by the solid-liquid phase separation method and the following freeze-drying method. The MSCs sheet, prepared by the temperature-responsive dish, was then layered on the top of the PLCL sheet and cultured for 2 weeks. During the in vitro study, cellular properties such as cell infiltration, spreading and proliferation were evaluated. Tensile test of the layered construct was performed periodically to characterize the tensile mechanical behavior. The tensile properties were then correlated with the cellular properties to understand the effect of MSCs sheet on the variation of the mechanical behavior during the in vitro study. It was found that MSCs from the cell sheet were able to migrate into the PLCL sheet and actively proliferated into the porous structure then formed a new layer of MSCs on the opposite surface of the PLCL sheet. Mechanical evaluation revealed that the PLCL sheet with MSCs showed enhancement of tensile strength and strain energy density at the first week of culture which is characterized as the effect of MSCs proliferation and its infiltration into the porous structure of the PLCL sheet. New technique was presented to develop tissue engineered patch by combining MSCs sheet and porous PLCL sheet, and it is expected that the layered patch may prolong biomechanical stability when implanted in vivo.

  15. Delayed minimally invasive injection of allogenic bone marrow stromal cell sheets regenerates large bone defects in an ovine preclinical animal model.

    Science.gov (United States)

    Berner, Arne; Henkel, Jan; Woodruff, Maria A; Steck, Roland; Nerlich, Michael; Schuetz, Michael A; Hutmacher, Dietmar W

    2015-05-01

    Cell-based tissue engineering approaches are promising strategies in the field of regenerative medicine. However, the mode of cell delivery is still a concern and needs to be significantly improved. Scaffolds and/or matrices loaded with cells are often transplanted into a bone defect immediately after the defect has been created. At this point, the nutrient and oxygen supply is low and the inflammatory cascade is incited, thus creating a highly unfavorable microenvironment for transplanted cells to survive and participate in the regeneration process. We therefore developed a unique treatment concept using the delayed injection of allogenic bone marrow stromal cell (BMSC) sheets to regenerate a critical-sized tibial defect in sheep to study the effect of the cells' regeneration potential when introduced at a postinflammatory stage. Minimally invasive percutaneous injection of allogenic BMSCs into biodegradable composite scaffolds 4 weeks after the defect surgery led to significantly improved bone regeneration compared with preseeded scaffold/cell constructs and scaffold-only groups. Biomechanical testing and microcomputed tomography showed comparable results to the clinical reference standard (i.e., an autologous bone graft). To our knowledge, we are the first to show in a validated preclinical large animal model that delayed allogenic cell transplantation can provide applicable clinical treatment alternatives for challenging bone defects in the future.

  16. QR Factorization for the Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Jakub Kurzak

    2009-01-01

    Full Text Available The QR factorization is one of the most important operations in dense linear algebra, offering a numerically stable method for solving linear systems of equations including overdetermined and underdetermined systems. Modern implementations of the QR factorization, such as the one in the LAPACK library, suffer from performance limitations due to the use of matrix–vector type operations in the phase of panel factorization. These limitations can be remedied by using the idea of updating of QR factorization, rendering an algorithm, which is much more scalable and much more suitable for implementation on a multi-core processor. It is demonstrated how the potential of the cell broadband engine can be utilized to the fullest by employing the new algorithmic approach and successfully exploiting the capabilities of the chip in terms of single instruction multiple data parallelism, instruction level parallelism and thread-level parallelism.

  17. Engineering the work function of buckled boron α-sheet by lithium adsorption: a first-principles investigation.

    Science.gov (United States)

    Zheng, Bing; Yu, Hai-tao; Xie, Ying; Lian, Yong-fu

    2014-11-26

    First-principles density functional theory calculations were performed to study the effect of Li adsorption on the structural and electronic properties, particularly the work function, of boron α-sheet. The calculated binding energies indicated that boron α-sheet could be well stabilized by the adsorption of Li atoms. Furthermore, the work functions of Li-adsorbed boron α-sheets were observed to decrease drastically with increasing Li coverage. The work functions are lower than that of Mg and even, for some of them, lower than that of Ca, indicating a considerable potential application of Li-adsorbed boron α-sheets as field-emission and electrode materials. Based on the calculated geometric and electronic structures, we discuss in details some possible aspects affecting the work function. The Li coverage dependence of the work functions of Li-adsorbed boron α-sheets was further confirmed by electrostatic potential analyses. The relationship between the work function variation and the Fermi and vacuum energy level shifts was also discussed, and we observed that the variation of the work function is primarily associated with the shift of the Fermi energy level. It is the surface dipole formed by the interaction between adatoms and substrate that should be responsible for the observed variation of the work function, whereas the increasing negative charge and rumpling for boron α-sheet only play minor roles. Additionally, the effect of Li adatoms on the work function of boron α-sheet was confirmed to be much stronger than that of graphene or a graphene double layer.

  18. The properties of bioengineered chondrocyte sheets for cartilage regeneration

    Directory of Open Access Journals (Sweden)

    Ota Naoshi

    2009-03-01

    Full Text Available Abstract Background Although the clinical results of autologous chondrocyte implantation for articular cartilage defects have recently improved as a result of advanced techniques based on tissue engineering procedures, problems with cell handling and scaffold imperfections remain to be solved. A new cell-sheet technique has been developed, and is potentially able to overcome these obstacles. Chondrocyte sheets applicable to cartilage regeneration can be prepared with this cell-sheet technique using temperature-responsive culture dishes. However, for clinical application, it is necessary to evaluate the characteristics of the cells in these sheets and to identify their similarities to naive cartilage. Results The expression of SOX 9, collagen type 2, 27, integrin α10, and fibronectin genes in triple-layered chondrocyte sheets was significantly increased in comparison to those in conventional monolayer culture and in a single chondrocyte sheet, implying a nature similar to ordinary cartilage. In addition, immunohistochemistry demonstrated that collagen type II, fibronectin, and integrin α10 were present in the triple-layered chondrocyte sheets. Conclusion The results of this study indicate that these chondrocyte sheets with a consistent cartilaginous phenotype and adhesive properties may lead to a new strategy for cartilage regeneration.

  19. Stem cell engineering for treatment of heart diseases: potentials and challenges.

    Science.gov (United States)

    Li, Shengwen Calvin; Wang, Lang; Jiang, Hong; Acevedo, Julyana; Chang, Anthony Christopher; Loudon, William Gunter

    2009-03-01

    Heart disorders are a major health concern worldwide responsible for millions of deaths every year. Among the many disorders of the heart, myocardial infarction, which can lead to the development of congestive heart failure, arrhythmias, or even death, has the most severe social and economic ramifications. Lack of sufficient available donor hearts for heart transplantation, the only currently viable treatment for heart failure other than medical management options (ACE inhibition, beta blockade, use of AICDs, etc.) that improve the survival of patients with heart failure emphasises the need for alternative therapies. One promising alternative replaces cardiac muscle damaged by myocardial infarction with new contractile cardiomyocytes and vessels obtained through stem cell-based regeneration. We report on the state of the art of recovery of cardiac functions by using stem cell engineering. Current research focuses on (a) inducing stem cells into becoming cardiac cells before or after injection into a host, (b) growing replacement heart tissue in vitro, and (c) stimulating the proliferation of the post-mitotic cardiomyocytes in situ. The most promising treatment option for patients is the engineering of new heart tissue that can be implanted into damaged areas. Engineering of cardiac tissue currently employs the use of co-culture of stem cells with scaffold microenvironments engineered to improve tissue survival and enhance differentiation. Growth of heart tissue in vitro using scaffolds, soluble collagen, and cell sheets has unique advantages. To compensate for the loss of ventricular mass and contractility of the injured cardiomyocytes, different stem cell populations have been extensively studied as potential sources of new cells to ameliorate the injured myocardium and eventually restore cardiac function. Unresolved issues including insufficient cell generation survival, growth, and differentiation have led to mixed results in preclinical and clinical studies

  20. Construction of Tissue Engineering Artificial Cornea with Skin Stem Cells

    Institute of Scientific and Technical Information of China (English)

    Yuan LIU; Yan JIN

    2005-01-01

    @@ 1 Introduction The clinical need for an alternative to donor corneal tissue has encouraged much interests in recent years. An artificial cornea must fulfill the functions of the cornea it replaces. More recently, the idea of a bio-engineered cornea has risen. Corneal equivalents have been reconstructed by tissue engineering method. Aim of this study is to construct an artificial rabbit cornea by employing tissue engineering method and to determine if skin stem cells have a role in tissue engineered cornea construction.

  1. The Principles of Engineering Immune Cells to Treat Cancer.

    Science.gov (United States)

    Lim, Wendell A; June, Carl H

    2017-02-09

    Chimeric antigen receptor (CAR) T cells have proven that engineered immune cells can serve as a powerful new class of cancer therapeutics. Clinical experience has helped to define the major challenges that must be met to make engineeredcells a reliable, safe, and effective platform that can be deployed against a broad range of tumors. The emergence of synthetic biology approaches for cellular engineering is providing us with a broadly expanded set of tools for programming immune cells. We discuss how these tools could be used to design the next generation of smart T cell precision therapeutics.

  2. Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

    Science.gov (United States)

    Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

    2000-04-01

    Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy.

  3. Highly Efficient Fuel Cell Electrodes from Few-Layer Graphene Sheets and Electrochemically Deposited Palladium Nanoparticles

    CERN Document Server

    Höltig, Michael; Kipp, Tobias; Mews, Alf

    2016-01-01

    An extremely efficient ethanol fuel cell electrode is produced by combining the large surface area of vertically oriented and highly conductive few-layer graphene sheets with electrochemically deposited palladium nanoparticles. The electrodes show an extraordinary high catalyst activity of up to 7977 mA/(mg Pd) at low catalyst loadings of 0.64 $\\mu$g/cm$^2$ and a very high current density of up to 106 mA/cm$^2$ at high catalyst loadings of 83 $\\mu$g/cm$^2$. Moreover, the low onset potentials combined with a good poisoning resistance and long-term stability make these electrodes highly suitable for real applications. These features are achieved by using a newly developed electrochemical catalyst deposition process exploiting high voltages of up to 3.5 kV. This technique allows controlling the catalyst amount ranging from a homogeneous widespread distribution of small ($\\leq$ 10 nm) palladium nanoparticles to rather dense layers of particles, while every catalyst particle has electrical contact to the graphene ...

  4. Non-genetic engineering of cells for drug delivery and cell-based therapy.

    Science.gov (United States)

    Wang, Qun; Cheng, Hao; Peng, Haisheng; Zhou, Hao; Li, Peter Y; Langer, Robert

    2015-08-30

    Cell-based therapy is a promising modality to address many unmet medical needs. In addition to genetic engineering, material-based, biochemical, and physical science-based approaches have emerged as novel approaches to modify cells. Non-genetic engineering of cells has been applied in delivering therapeutics to tissues, homing of cells to the bone marrow or inflammatory tissues, cancer imaging, immunotherapy, and remotely controlling cellular functions. This new strategy has unique advantages in disease therapy and is complementary to existing gene-based cell engineering approaches. A better understanding of cellular systems and different engineering methods will allow us to better exploit engineered cells in biomedicine. Here, we review non-genetic cell engineering techniques and applications of engineered cells, discuss the pros and cons of different methods, and provide our perspectives on future research directions.

  5. Cell-Based Strategies for Meniscus Tissue Engineering

    Science.gov (United States)

    Niu, Wei; Guo, Weimin; Han, Shufeng; Zhu, Yun; Liu, Shuyun; Guo, Quanyi

    2016-01-01

    Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a fundamental role in meniscal regeneration. According to current studies, the main cell-based strategies for meniscus tissue engineering are single cell type strategies; cell coculture strategies also were applied to meniscus tissue engineering. Likewise, on the one side, the zonal recapitulation strategies based on mimicking meniscal differing cells and internal architectures have received wide attentions. On the other side, cell self-assembling strategies without any scaffolds may be a better way to build a bionic meniscus. In this review, we primarily discuss cell seeds for meniscus tissue engineering and their application strategies. We also discuss recent advances and achievements in meniscus repair experiments that further improve our understanding of meniscus tissue engineering. PMID:27274735

  6. Cell-Based Strategies for Meniscus Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Wei Niu

    2016-01-01

    Full Text Available Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a fundamental role in meniscal regeneration. According to current studies, the main cell-based strategies for meniscus tissue engineering are single cell type strategies; cell coculture strategies also were applied to meniscus tissue engineering. Likewise, on the one side, the zonal recapitulation strategies based on mimicking meniscal differing cells and internal architectures have received wide attentions. On the other side, cell self-assembling strategies without any scaffolds may be a better way to build a bionic meniscus. In this review, we primarily discuss cell seeds for meniscus tissue engineering and their application strategies. We also discuss recent advances and achievements in meniscus repair experiments that further improve our understanding of meniscus tissue engineering.

  7. Training human mesenchymal stromal cells for bone tissue engineering applications

    NARCIS (Netherlands)

    Doorn, J.

    2012-01-01

    Human mesenchymal stromal cells (hMSCs) are an interesting source for cell therapies and tissue engineering applications, because these cells are able to differentiate into various target tissues, such as bone, cartilage, fat and endothelial cells. In addition, they secrete a wide array of growth fa

  8. Engineering models and methods for industrial cell control

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1997-01-01

    control and monitor-ing systems for production cells. The project participants are The Danish Academy of Technical Sciences, the Institute of Manufacturing Engineering at the Technical University of Denmark and ODENSE STEEL SHIPYARD Ltd.The manufacturing environment and the current practice......This paper is concerned with the engineering, i.e. the designing and making, of industrial cell control systems. The focus is on automated robot welding cells in the shipbuilding industry. The industrial research project defines models and methods for design and implemen-tation of computer based....... Further, an engineering methodology is defined. The three elements enablers, architecture and methodology constitutes the Cell Control Engineering concept which has been defined and evaluated through the implementation of two cell control systems for robot welding cells in production at ODENSE STEEL...

  9. Glycosylation Helps Cellulase Enzymes Bind to Plant Cell Walls (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-06-01

    Computer simulations suggest a new strategy to design enhanced enzymes for biofuels production. Large-scale computer simulations predict that the addition of glycosylation on carbohydrate-binding modules can dramatically improve the binding affinity of these protein domains over amino acid mutations alone. These simulations suggest that glycosylation can be used as a protein engineering tool to enhance the activity of cellulase enzymes, which are a key component in the conversion of cellulose to soluble sugars in the production of biofuels. Glycosylation is the covalent attachment of carbohydrate molecules to protein side chains, and is present in many proteins across all kingdoms of life. Moreover, glycosylation is known to serve a wide variety of functions in biological recognition, cell signaling, and metabolism. Cellulase enzymes, which are responsible for deconstructing cellulose found in plant cell walls to glucose, contain glycosylation that when modified can affect enzymatic activity-often in an unpredictable manner. To gain insight into the role of glycosylation on cellulase activity, scientists at the National Renewable Energy Laboratory (NREL) used computer simulation to predict that adding glycosylation on the carbohydrate-binding module of a cellulase enzyme dramatically boosts the binding affinity to cellulose-more than standard protein engineering approaches in which amino acids are mutated. Because it is known that higher binding affinity in cellulases leads to higher activity, this work suggests a new route to designing enhanced enzymes for biofuels production. More generally, this work suggests that tuning glycosylation in cellulase enzymes is a key factor to consider when engineering biochemical conversion processes, and that more work is needed to understand how glycosylation affects cellulase activity at the molecular level.

  10. Hypoxia and Stem Cell-Based Engineering of Mesenchymal Tissues

    OpenAIRE

    Ma, Teng; Grayson, Warren L.; Fröhlich, Mirjam; Vunjak-Novakovic, Gordana

    2009-01-01

    Stem cells have the ability for prolonged self-renewal and differentiation into mature cells of various lineages, which makes them important cell sources for tissue engineering applications. Their remarkable ability to replenish and differentiate in vivo is regulated by both intrinsic and extrinsic cellular mechanisms. The anatomical location where the stem cells reside, known as the “stem cell niche or microenvironment,” provides signals conducive to the maintenance of definitive stem cell p...

  11. Dynamic culture induces a cell type-dependent response impacting on the thickness of engineered connective tissues.

    Science.gov (United States)

    Fortier, Guillaume Marceau; Gauvin, Robert; Proulx, Maryse; Vallée, Maud; Fradette, Julie

    2013-04-01

    Mesenchymal cells are central to connective tissue homeostasis and are widely used for tissue-engineering applications. Dermal fibroblasts and adipose-derived stromal cells (ASCs) allow successful tissue reconstruction by the self-assembly approach of tissue engineering. This method leads to the production of multilayered tissues, devoid of exogenous biomaterials, that can be used as stromal compartments for skin or vesical reconstruction. These tissues are formed by combining cell sheets, generated through cell stimulation with ascorbic acid, which favours the cell-derived production/organization of matrix components. Since media motion can impact on cell behaviour, we investigated the effect of dynamic culture on mesenchymal cells during tissue reconstruction, using the self-assembly method. Tissues produced using ASCs in the presence of a wave-like movement were nearly twice thicker than under standard conditions, while no difference was observed for tissues produced from dermal fibroblasts. The increased matrix deposition was not correlated with an increased proliferation of ASCs, or by higher transcript levels of fibronectin or collagens I and III. A 30% increase of type V collagen mRNA was observed. Interestingly, tissues engineered from dermal fibroblasts featured a four-fold higher level of MMP-1 transcripts under dynamic conditions. Mechanical properties were similar for tissues reconstructed using dynamic or static conditions. Finally, cell sheets produced using ASCs under dynamic conditions could readily be manipulated, resulting in a 2 week reduction of the production time (from 5 to 3 weeks). Our results describe a distinctive property of ASCs' response to media motion, indicating that their culture under dynamic conditions leads to optimized tissue engineering.

  12. Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

    Directory of Open Access Journals (Sweden)

    Wan Nurlina Wan Yahya

    2014-07-01

    Full Text Available Liver transplantation is the most common treatment for patients with end-stage liver failure. However, liver transplantation is greatly limited by a shortage of donors. Liver tissue engineering may offer an alternative by providing an implantable engineered liver. Currently, diverse types of engineering approaches for in vitro liver cell culture are available, including scaffold-based methods, microfluidic platforms, and micropatterning techniques. Active cell patterning via dielectrophoretic (DEP force showed some advantages over other methods, including high speed, ease of handling, high precision and being label-free. This article summarizes liver function and regenerative mechanisms for better understanding in developing engineered liver. We then review recent advances in liver tissue engineering techniques and focus on DEP-based cell patterning, including microelectrode design and patterning configuration.

  13. Energizing Engineering Students with Hydrogen Fuel Cell Project

    Science.gov (United States)

    Cannell, Nori; Zavaleta, Dan

    2010-01-01

    At Desert Vista High School, near Phoenix, Arizona, Perkins Innovation Grant funding is being used to fund a program that is helping to prepare students for careers in engineering by giving them hands-on experience in areas like hydrogen generation and fuel cell utilization. As one enters Dan Zavaleta's automotive and engineering classroom and lab…

  14. Fuel Cell Car Design Project for Freshman Engineering Courses

    Science.gov (United States)

    Duke, Steve R.; Davis, Virginia A.

    2014-01-01

    In the Samuel Ginn College of Engineering at Auburn University, we have integrated a semester long design project based on a toy fuel cell car into our freshman "Introduction to Chemical Engineering Class." The project provides the students a basic foundation in chemical reactions, energy, and dimensional analysis that facilitates…

  15. Cell death in mammalian cell culture: molecular mechanisms and cell line engineering strategies.

    Science.gov (United States)

    Krampe, Britta; Al-Rubeai, Mohamed

    2010-07-01

    Cell death is a fundamentally important problem in cell lines used by the biopharmaceutical industry. Environmental stress, which can result from nutrient depletion, by-product accumulation and chemical agents, activates through signalling cascades regulators that promote death. The best known key regulators of death process are the Bcl-2 family proteins which constitute a critical intracellular checkpoint of apoptosis cell death within a common death pathway. Engineering of several members of the anti-apoptosis Bcl-2 family genes in several cell types has extended the knowledge of their molecular function and interaction with other proteins, and their regulation of cell death. In this review, we describe the various modes of cell death and their death pathways at molecular and organelle level and discuss the relevance of the growing knowledge of anti-apoptotic engineering strategies to inhibit cell death and increase productivity in mammalian cell culture.

  16. Construction of Tissue Engineering Artificial Cornea with Skin Stem Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionThe clinical need for an alternative to donor corneal tissue has encouraged much interests in recent years. An artificial cornea must fulfill the functions of the cornea it replaces. More recently, the idea of a bio-engineered cornea has risen. Corneal equivalents have been reconstructed by tissue engineering method. Aim of this study is to construct an artificial rabbit cornea by employing tissue engineering method and to determine if skin stem cells have a role in tissue engineered cornea co...

  17. Stem and progenitor cells: advancing bone tissue engineering.

    Science.gov (United States)

    Tevlin, R; Walmsley, G G; Marecic, O; Hu, Michael S; Wan, D C; Longaker, M T

    2016-04-01

    Unlike many other postnatal tissues, bone can regenerate and repair itself; nevertheless, this capacity can be overcome. Traditionally, surgical reconstructive strategies have implemented autologous, allogeneic, and prosthetic materials. Autologous bone--the best option--is limited in supply and also mandates an additional surgical procedure. In regenerative tissue engineering, there are myriad issues to consider in the creation of a functional, implantable replacement tissue. Importantly, there must exist an easily accessible, abundant cell source with the capacity to express the phenotype of the desired tissue, and a biocompatible scaffold to deliver the cells to the damaged region. A literature review was performed using PubMed; peer-reviewed publications were screened for relevance in order to identify key advances in stem and progenitor cell contribution to the field of bone tissue engineering. In this review, we briefly introduce various adult stem cells implemented in bone tissue engineering such as mesenchymal stem cells (including bone marrow- and adipose-derived stem cells), endothelial progenitor cells, and induced pluripotent stem cells. We then discuss numerous advances associated with their application and subsequently focus on technological advances in the field, before addressing key regenerative strategies currently used in clinical practice. Stem and progenitor cell implementation in bone tissue engineering strategies have the ability to make a major impact on regenerative medicine and reduce patient morbidity. As the field of regenerative medicine endeavors to harness the body's own cells for treatment, scientific innovation has led to great advances in stem cell-based therapies in the past decade.

  18. Reconstruction of Multiple Facial Nerve Branches Using Skeletal Muscle-Derived Multipotent Stem Cell Sheet-Pellet Transplantation.

    Directory of Open Access Journals (Sweden)

    Kosuke Saito

    Full Text Available Head and neck cancer is often diagnosed at advanced stages, and surgical resection with wide margins is generally indicated, despite this treatment being associated with poor postoperative quality of life (QOL. We have previously reported on the therapeutic effects of skeletal muscle-derived multipotent stem cells (Sk-MSCs, which exert reconstitution capacity for muscle-nerve-blood vessel units. Recently, we further developed a 3D patch-transplantation system using Sk-MSC sheet-pellets. The aim of this study is the application of the 3D Sk-MSC transplantation system to the reconstitution of facial complex nerve-vascular networks after severe damage. Mouse experiments were performed for histological analysis and rats were used for functional examinations. The Sk-MSC sheet-pellets were prepared from GFP-Tg mice and SD rats, and were transplanted into the facial resection model (ST. Culture medium was transplanted as a control (NT. In the mouse experiment, facial-nerve-palsy (FNP scoring was performed weekly during the recovery period, and immunohistochemistry was used for the evaluation of histological recovery after 8 weeks. In rats, contractility of facial muscles was measured via electrical stimulation of facial nerves root, as the marker of total functional recovery at 8 weeks after transplantation. The ST-group showed significantly higher FNP (about three fold scores when compared to the NT-group after 2-8 weeks. Similarly, significant functional recovery of whisker movement muscles was confirmed in the ST-group at 8 weeks after transplantation. In addition, engrafted GFP+ cells formed complex branches of nerve-vascular networks, with differentiation into Schwann cells and perineurial/endoneurial cells, as well as vascular endothelial and smooth muscle cells. Thus, Sk-MSC sheet-pellet transplantation is potentially useful for functional reconstitution therapy of large defects in facial nerve-vascular networks.

  19. Genetic engineering of human pluripotent cells using TALE nucleases.

    Science.gov (United States)

    Hockemeyer, Dirk; Wang, Haoyi; Kiani, Samira; Lai, Christine S; Gao, Qing; Cassady, John P; Cost, Gregory J; Zhang, Lei; Santiago, Yolanda; Miller, Jeffrey C; Zeitler, Bryan; Cherone, Jennifer M; Meng, Xiangdong; Hinkley, Sarah J; Rebar, Edward J; Gregory, Philip D; Urnov, Fyodor D; Jaenisch, Rudolf

    2011-07-07

    Targeted genetic engineering of human pluripotent cells is a prerequisite for exploiting their full potential. Such genetic manipulations can be achieved using site-specific nucleases. Here we engineered transcription activator-like effector nucleases (TALENs) for five distinct genomic loci. At all loci tested we obtained human embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) clones carrying transgenic cassettes solely at the TALEN-specified location. Our data suggest that TALENs employing the specific architectures described here mediate site-specific genome modification in human pluripotent cells with similar efficiency and precision as do zinc-finger nucleases (ZFNs).

  20. Implementation of Scientific Computing Applications on the Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Guochun Shi

    2009-01-01

    Full Text Available The Cell Broadband Engine architecture is a revolutionary processor architecture well suited for many scientific codes. This paper reports on an effort to implement several traditional high-performance scientific computing applications on the Cell Broadband Engine processor, including molecular dynamics, quantum chromodynamics and quantum chemistry codes. The paper discusses data and code restructuring strategies necessary to adapt the applications to the intrinsic properties of the Cell processor and demonstrates performance improvements achieved on the Cell architecture. It concludes with the lessons learned and provides practical recommendations on optimization techniques that are believed to be most appropriate.

  1. How to prevent contamination with Candida albicans during the fabrication of transplantable oral mucosal epithelial cell sheets

    Directory of Open Access Journals (Sweden)

    Ryo Takagi

    2015-06-01

    Full Text Available We have utilized patients' own oral mucosa as a cell source for the fabrication of transplantable epithelial cell sheets to treat limbal stem cell deficiency and mucosal defects after endoscopic submucosal dissection of esophageal cancer. Because there are abundant microbiotas in the human oral cavity, the oral mucosa was sterilized and 40 μg/mL gentamicin and 0.27 μg/mL amphotericin B were added to the culture medium in our protocol. Although an oral surgeon carefully checked each patient's oral cavity and although candidiasis was not observed before taking the biopsy, contamination with Candida albicans (C. albicans was detected in the conditioned medium during cell sheet fabrication. After adding 1 μg/mL amphotericin B to the transportation medium during transport from Nagasaki University Hospital to Tokyo Women's Medical University, which are 1200 km apart, no proliferation of C. albicans was observed. These results indicated that the supplementation of transportation medium with antimycotics would be useful for preventing contamination with C. albicans derived from the oral mucosa without hampering cell proliferation.

  2. Mesenchymal stem cells support hepatocyte function in engineered liver grafts.

    Science.gov (United States)

    Kadota, Yoshie; Yagi, Hiroshi; Inomata, Kenta; Matsubara, Kentaro; Hibi, Taizo; Abe, Yuta; Kitago, Minoru; Shinoda, Masahiro; Obara, Hideaki; Itano, Osamu; Kitagawa, Yuko

    2014-01-01

    Recent studies suggest that organ decellularization is a promising approach to facilitate the clinical application of regenerative therapy by providing a platform for organ engineering. This unique strategy uses native matrices to act as a reservoir for the functional cells which may show therapeutic potential when implanted into the body. Appropriate cell sources for artificial livers have been debated for some time. The desired cell type in artificial livers is primary hepatocytes, but in addition, other supportive cells may facilitate this stem cell technology. In this context, the use of mesenchymal stem cells (MSC) is an option meeting the criteria for therapeutic organ engineering. Ideally, supportive cells are required to (1) reduce the hepatic cell mass needed in an engineered liver by enhancing hepatocyte function, (2) modulate hepatic regeneration in a paracrine fashion or by direct contact, and (3) enhance the preservability of parenchymal cells during storage. Here, we describe enhanced hepatic function achieved using a strategy of sequential infusion of cells and illustrate the advantages of co-cultivating bone marrow-derived MSCs with primary hepatocytes in the engineered whole-liver scaffold. These co-recellularized liver scaffolds colonized by MSCs and hepatocytes were transplanted into live animals. After blood flow was established, we show that expression of adhesion molecules and proangiogenic factors was upregulated in the graft.

  3. MATE (Materials for Advanced Turbine Engines) Program, Project 3. Volume 2: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner

    Science.gov (United States)

    Bose, S.; Sheffler, K. D.

    1988-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Two yttria (Y2O3) dispersion strengthened alloys were evaluated; Incoloy MA956 and Haynes Development Alloy (HDA) 8077 (NiCrAl base). Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. MA956 was selected as the final alloy based on manufacturing reproducibility for evaluation as a burner liner. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components and using a louvered configuration was designed and constructed. The louvered configuration was chosen because of field experience and compatibility with the bill of material PW2037 design. The simulated flight cycle for the ground based engine tests consisted of 4.5 min idle, 1.5 min takeoff and intermediate conditions in a PW2037 engine with average uncorrected combustor exit temperature of 1527 C. Post test evaluation consisting of visual observations and fluorescent penetrant inspections was conducted after 500 cycles of testing. No loss of integrity in the burner liner was shown.

  4. Assembly of cells and vesicles for organ engineering

    Directory of Open Access Journals (Sweden)

    Tetsushi Taguchi

    2011-01-01

    Full Text Available The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration.

  5. Assembly of cells and vesicles for organ engineering

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Tetsushi, E-mail: taguchi.tetsushi@nims.go.jp [Biofunctional Materials Unit, Nano-Bio Field, Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2011-12-15

    The development of materials and technologies for the assembly of cells and/or vesicles is a key for the next generation of tissue engineering. Since the introduction of the tissue engineering concept in 1993, various types of scaffolds have been developed for the regeneration of connective tissues in vitro and in vivo. Cartilage, bone and skin have been successfully regenerated in vitro, and these regenerated tissues have been applied clinically. However, organs such as the liver and pancreas constitute numerous cell types, contain small amounts of extracellular matrix, and are highly vascularized. Therefore, organ engineering will require the assembly of cells and/or vesicles. In particular, adhesion between cells/vesicles will be required for regeneration of organs in vitro. This review introduces and discusses the key technologies and materials for the assembly of cells/vesicles for organ regeneration. (topical review)

  6. Light-sheet Bayesian microscopy enables deep-cell super-resolution imaging of heterochromatin in live human embryonic stem cells

    Science.gov (United States)

    Hu, Ying S; Zhu, Quan; Elkins, Keri; Tse, Kevin; Li, Yu; Fitzpatrick, James A J; Verma, Inder M; Cang, Hu

    2016-01-01

    Background Heterochromatin in the nucleus of human embryonic cells plays an important role in the epigenetic regulation of gene expression. The architecture of heterochromatin and its dynamic organization remain elusive because of the lack of fast and high-resolution deep-cell imaging tools. We enable this task by advancing instrumental and algorithmic implementation of the localization-based super-resolution technique. Results We present light-sheet Bayesian super-resolution microscopy (LSBM). We adapt light-sheet illumination for super-resolution imaging by using a novel prism-coupled condenser design to illuminate a thin slice of the nucleus with high signal-to-noise ratio. Coupled with a Bayesian algorithm that resolves overlapping fluorophores from high-density areas, we show, for the first time, nanoscopic features of the heterochromatin structure in both fixed and live human embryonic stem cells. The enhanced temporal resolution allows capturing the dynamic change of heterochromatin with a lateral resolution of 50–60 nm on a time scale of 2.3 s. Conclusion Light-sheet Bayesian microscopy opens up broad new possibilities of probing nanometer-scale nuclear structures and real-time sub-cellular processes and other previously difficult-to-access intracellular regions of living cells at the single-molecule, and single cell level.

  7. Cell death in mammalian cell culture: molecular mechanisms and cell line engineering strategies

    OpenAIRE

    Krampe, Britta; Al-Rubeai, Mohamed

    2010-01-01

    Cell death is a fundamentally important problem in cell lines used by the biopharmaceutical industry. Environmental stress, which can result from nutrient depletion, by-product accumulation and chemical agents, activates through signalling cascades regulators that promote death. The best known key regulators of death process are the Bcl-2 family proteins which constitute a critical intracellular checkpoint of apoptosis cell death within a common death pathway. Engineering of several members o...

  8. Strategies to genetically engineer T cells for cancer immunotherapy.

    Science.gov (United States)

    Spear, Timothy T; Nagato, Kaoru; Nishimura, Michael I

    2016-06-01

    Immunotherapy is one of the most promising and innovative approaches to treat cancer, viral infections, and other immune-modulated diseases. Adoptive immunotherapy using gene-modified T cells is an exciting and rapidly evolving field. Exploiting knowledge of basic T cell biology and immune cell receptor function has fostered innovative approaches to modify immune cell function. Highly translatable clinical technologies have been developed to redirect T cell specificity by introducing designed receptors. The ability to engineer T cells to manifest desired phenotypes and functions is now a thrilling reality. In this review, we focus on outlining different varieties of genetically engineered T cells, their respective advantages and disadvantages as tools for immunotherapy, and their promise and drawbacks in the clinic.

  9. Concise review: Human cell engineering: cellular reprogramming and genome editing.

    Science.gov (United States)

    Mali, Prashant; Cheng, Linzhao

    2012-01-01

    Cell engineering is defined here as the collective ability to both reset and edit the genome of a mammalian cell. Until recently, this had been extremely challenging to achieve as nontransformed human cells are significantly refractory to both these processes. The recent success in reprogramming somatic cells into induced pluripotent stem cells that are self-renewable in culture, coupled with our increasing ability to effect precise and predesigned genomic editing, now readily permits cellular changes at both the genetic and epigenetic levels. These dual capabilities also make possible the generation of genetically matched, disease-free stem cells from patients for regenerative medicine. The objective of this review is to summarize the key enabling developments on these two rapidly evolving research fronts in human cell engineering, highlight unresolved issues, and outline potential future research directions.

  10. Cell surface engineering with edible protein nanoshells.

    Science.gov (United States)

    Drachuk, Irina; Shchepelina, Olga; Harbaugh, Svetlana; Kelley-Loughnane, Nancy; Stone, Morley; Tsukruk, Vladimir V

    2013-09-23

    Natural protein (silk fibroin) nanoshells are assembled on the surface of Saccharomyces cerevisiae yeast cells without compromising their viability. The nanoshells facilitate initial protection of the cells and allow them to function in encapsulated state for some time period, afterwards being completely biodegraded and consumed by the cells. In contrast to a traditional methanol treatment, the gentle ionic treatment suggested here stabilizes the shell silk fibroin structure but does not compromise the viability of the cells, as indicated by the fast response of the encapsulated cells, with an immediate activation by the inducer molecules. Extremely high viability rates (up to 97%) and preserved activity of encapsulated cells are facilitated by cytocompatibility of the natural proteins and the formation of highly porous shells in contrast to traditional polyelectrolyte-based materials. Moreover, in a high contrast to traditional synthetic shells, the silk proteins are biodegradable and can be consumed by cells at a later stage of growth, thus releasing the cells from their temporary protective capsules. These on-demand encapsulated cells can be considered a valuable platform for biocompatible and biodegradable cell encapsulation, controlled cell protection in a synthetic environment, transfer to a device environment, and cell implantation followed by biodegradation and consumption of protective protein shells.

  11. Distributed Shared Memory for the Cell Broadband Engine (DSMCBE)

    DEFF Research Database (Denmark)

    Larsen, Morten Nørgaard; Skovhede, Kenneth; Vinter, Brian

    2009-01-01

    in and out of non-coherent local storage blocks for each special processor element. In this paper we present a software library, namely the Distributed Shared Memory for the Cell Broadband Engine (DSMCBE). By using techniques known from distributed shared memory DSMCBE allows programmers to program the CELL...

  12. Engineering considerations for process development in mammalian cell cultivation.

    Science.gov (United States)

    Zhang, Hu; Wang, Weixiang; Quan, Chunshan; Fan, Shengdi

    2010-01-01

    Mammalian cell cultivation plays a great role in producing protein therapeutics in the last decades. Many engineering parameters are considered for optimization during process development in mammalian cell cultivation, only shear and mixing are especially highlighted in this paper. It is believed that shear stress due to agitation has been over-estimated to damage cells, but shear may result in nonlethal physiological responses. There is no cell damage in the regions where bubbles form, break up and coalescence, but shear stress becomes significant in the wake of rising bubbles and causes great damage to cells in bubble burst regions. Mixing is not sufficient to provide homogeneous dissolved oxygen tension, pH, CO2 and nutrients in large-scale bioreactors, which can bring severe problems for cell growth, product formation and process control. Scale-down reactors have been developed to address mixing and shear problems for parallel operations. Engineering characterization in conventional and recently developed scale-down bioreactors has been briefly introduced. Process challenges for cultivation of industrial cell lines in high cell densities as well as cultivation of stem cells and other human cells for regenerative medicine, tissue engineering and gene therapy are prospected. Important techniques, such as micromanipulation and nanomanipulation (optical tweezers) for single cell analysis, computational fluid dynamics (CFD) for shear and mixing characterization, and miniaturized bioreactors, are being developed to address those challenges.

  13. Virgin birth: engineered heart muscle from parthenogenetic stem cells.

    Science.gov (United States)

    McSweeney, Sara J; Schneider, Michael D

    2013-03-01

    Cardiac muscle restitution, or true regeneration, is an unmet need in the treatment of myocardial infarction (MI), prompting a decade of study with stem cells of many kinds. Among key obstacles to effective cardiac cell grafting are the cost of autologous stem cell-derived cardiomyocytes, the ethical implications of using embryonic stem cell (ESC) products, immunological barriers to allogeneic cells, functional maturation beyond just the correct lineage decision, and the lack of durable engraftment. In this issue of the JCI, Didié and colleagues show that cardiomyocytes made from parthenogenetic stem cells (PSCs) and deployed as engineered heart muscle (EHM) may overcome all of these formidable barriers.

  14. [The microencapsulated genetic engineering cells: a new platform on treatment of cancer instead of genetic engineering drugs].

    Science.gov (United States)

    Pan, Yuelong; Zheng, Shu

    2003-06-01

    The microencapsulated genetic cells may be a new platform instead of genetic engineering drugs, as they can overcome the genetic engineering drugs' shortages such as short half-life in vivo, low activity, and incomplete elimination of organic solvent. This article reviews and summarizes the advantages, possible problems and solution and the feasibility of using microencapsulated genetic engineering cells in the treatment of cancer.

  15. Chemical engineering of cell penetrating antibodies.

    Science.gov (United States)

    Zhao, Y; Lou, D; Burkett, J; Kohler, H

    2001-08-01

    Antibodies, being exquisitely specific tools in biology, are routinely used to detect and identify intra-cellular structures. However, current intra-cellular application of antibodies requires that the membrane be rendered leaky, resulting in the death of cells. Here, we present a novel method to allow antibodies to penetrate the cellular membrane of living cells without affecting cell viability. A peptide (MTS, membrane transport sequence) that facilitates transport across membranes has been site-specifically attached to antibodies. MTS-antibodies enter the living cells in culture and can be detected by immunofluorescence and ELISA after extraction. Cellular structures are visualized in living cells using a specific MTS-antibody. Antibodies with membrane penetrating properties can become an important tool for the study of intra-cellular processes in living cells. Furthermore, such membrane penetrating antibodies can be used to selectively stimulate or suppress functions of the cellular machinery.

  16. Allogeneic Transplantation of an Adipose-Derived Stem Cell Sheet Combined With Artificial Skin Accelerates Wound Healing in a Rat Wound Model of Type 2 Diabetes and Obesity.

    Science.gov (United States)

    Kato, Yuka; Iwata, Takanori; Morikawa, Shunichi; Yamato, Masayuki; Okano, Teruo; Uchigata, Yasuko

    2015-08-01

    One of the most common complications of diabetes is diabetic foot ulcer. Diabetic ulcers do not heal easily due to diabetic neuropathy and reduced blood flow, and nonhealing ulcers may progress to gangrene, which necessitates amputation of the patient's foot. This study attempted to develop a new cell-based therapy for nonhealing diabetic ulcers using a full-thickness skin defect in a rat model of type 2 diabetes and obesity. Allogeneic adipose-derived stem cells (ASCs) were harvested from the inguinal fat of normal rats, and ASC sheets were created using cell sheet technology and transplanted into full-thickness skin defects in Zucker diabetic fatty rats. The results indicate that the transplantation of ASC sheets combined with artificial skin accelerated wound healing and vascularization, with significant differences observed 2 weeks after treatment. The ASC sheets secreted large amounts of several angiogenic growth factors in vitro, and transplanted ASCs were observed in perivascular regions and incorporated into the newly constructed vessel structures in vivo. These results suggest that ASC sheets accelerate wound healing both directly and indirectly in this diabetic wound-healing model. In conclusion, allogeneic ASC sheets exhibit potential as a new therapeutic strategy for the treatment of diabetic ulcers.

  17. Materials for Advanced Turbine Engines (MATE): Project 3: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner, volume 1

    Science.gov (United States)

    Henricks, R. J.; Sheffler, K. D.

    1984-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Incoloy MA 956 (FeCrAl base) and Haynes Developmental Alloy (HDA) 8077 (NiCrAl base) were evaluated. Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. Both alloys demonstrated a +167C (300 F) advantage of creep and oxidation resistance with no improvement in thermal fatigue capability compared to a current generation combustor alloy (Hastelloy X). MA956 alloy was selected for further demonstration because it exhibited better manufacturing reproducibility than HDA8077. Additional property tests were conducted on MA956. To accommodate the limited thermal fatigue capability of ODS alloys, two segmented, mechanically attached, low strain ODS combustor design concepts having predicted fatigue lives or = 10,000 engine cycles were identified. One of these was a relatively conventional louvered geometry, while the other involved a transpiration cooled configuration. A series of 10,000 cycle combustor rig tests on subscale MA956 and Hastelloy X combustor components showed no cracking, thereby confirming the beneficial effect of the segmented design on thermal fatigue capability. These tests also confirmed the superior oxidation and thermal distortion resistance of the ODS alloy. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components was designed and constructed.

  18. Utilizing stem cells for three-dimensional neural tissue engineering.

    Science.gov (United States)

    Knowlton, Stephanie; Cho, Yongku; Li, Xue-Jun; Khademhosseini, Ali; Tasoglu, Savas

    2016-05-26

    Three-dimensional neural tissue engineering has made great strides in developing neural disease models and replacement tissues for patients. However, the need for biomimetic tissue models and effective patient therapies remains unmet. The recent push to expand 2D neural tissue engineering into the third dimension shows great potential to advance the field. Another area which has much to offer to neural tissue engineering is stem cell research. Stem cells are well known for their self-renewal and differentiation potential and have been shown to give rise to tissues with structural and functional properties mimicking natural organs. Application of these capabilities to 3D neural tissue engineering may be highly useful for basic research on neural tissue structure and function, engineering disease models, designing tissues for drug development, and generating replacement tissues with a patient's genetic makeup. Here, we discuss the vast potential, as well as the current challenges, unique to integration of 3D fabrication strategies and stem cells into neural tissue engineering. We also present some of the most significant recent achievements, including nerve guidance conduits to facilitate better healing of nerve injuries, functional 3D biomimetic neural tissue models, physiologically relevant disease models for research purposes, and rapid and effective screening of potential drugs.

  19. Engineered peptide-based nanobiomaterials for electrochemical cell chip

    Science.gov (United States)

    Kafi, Md. Abdul; Cho, Hyeon-Yeol; Choi, Jeong-Woo

    2016-07-01

    Biomaterials having cell adhesion ability are considered to be integral part of a cell chip. A number of researches have been carried out to search for a suitable material for effective immobilization of cell on substrate. Engineered ECM materials or their components like collagen, Poly- l-Lysine (PLL), Arg-Gly-Asp (RGD) peptide have been extensively used for mammalian cell adhesion and proliferation with the aim of tissue regeneration or cell based sensing application. This review focuses on the various approaches for two- and three-dimensionally patterned nanostructures of a short peptide i.e. RGD peptide on chip surfaces together with their effects on cell behaviors and electrochemical measurements. Most of the study concluded with positive remarks on the well-oriented engineered RGD peptide over their homogenous thin film. The engineered RGD peptide not only influences cell adhesion, spreading and proliferation but also their periodic nano-arrays directly influence electrochemical measurements of the chips. The electrochemical signals found to be enhanced when RGD peptides were used in well-defined two-dimensional nano-arrays. The topographic alteration of three-dimensional structure of engineered RGD peptide was reported to be suitably contacted with the integrin receptors of cellular membrane which results indicated the enhanced cell-electrode adhesion and efficient electron exchange phenomenon. This enhanced electrochemical signal increases the sensitivity of the chip against the target analytes. Therefore, development of engineered cellular recognizable peptides and its 3D topological design for fabrication of cell chip will provide the synergetic effect on bio-affinity, sensitivity and accuracy for the in situ real-time monitoring of analytes.

  20. T cell receptor-engineered T cells to treat solid tumors: T cell processing toward optimal T cell fitness

    NARCIS (Netherlands)

    C.H.J. Lamers (Cor); S. van Steenbergen-Langeveld (Sabine); M. van Brakel (Mandy); C.M. Groot-van Ruijven (Corrien); P.M.M.L. van Elzakker (Pascal); B.A. van Krimpen (Brigitte); S. Sleijfer (Stefan); J.E.M.A. Debets (Reno)

    2014-01-01

    textabstractTherapy with autologous T cells that have been gene-engineered to express chimeric antigen receptors (CAR) or T cell receptors (TCR) provides a feasible and broadly applicable treatment for cancer patients. In a clinical study in advanced renal cell carcinoma (RCC) patients with CAR T ce

  1. Optimal Materials and Deposition Technique Lead to Cost-Effective Solar Cell with Best-Ever Conversion Efficiency (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    This fact sheet describes how the SJ3 solar cell was invented, explains how the technology works, and why it won an R&D 100 Award. Based on NREL and Solar Junction technology, the commercial SJ3 concentrator solar cell - with 43.5% conversion efficiency at 418 suns - uses a lattice-matched multijunction architecture that has near-term potential for cells with {approx}50% efficiency. Multijunction solar cells have higher conversion efficiencies than any other type of solar cell. But developers of utility-scale and space applications crave even better efficiencies at lower costs to be both cost-effective and able to meet the demand for power. The SJ3 multijunction cell, developed by Solar Junction with assistance from foundational technological advances by the National Renewable Energy Laboratory, has the highest efficiency to date - almost 2% absolute more than the current industry standard multijunction cell-yet at a comparable cost. So what did it take to create this cell having 43.5% efficiency at 418-sun concentration? A combination of materials with carefully designed properties, a manufacturing technique allowing precise control, and an optimized device design.

  2. Micro & nano-engineering of fuel cells

    CERN Document Server

    Leung, Dennis YC

    2015-01-01

    Fuel cells are clean and efficient energy conversion devices expected to be the next generation power source. During more than 17 decades of research and development, various types of fuel cells have been developed with a view to meet the different energy demands and application requirements. Scientists have devoted a great deal of time and effort to the development and commercialization of fuel cells important for our daily lives. However, abundant issues, ranging from mechanistic study to system integration, still need to be figured out before massive applications can be used. Miniaturizatio

  3. Engineering the electrochemical capacitive properties of graphene sheets in ionic-liquid electrolytes by correct selection of anions.

    Science.gov (United States)

    Shi, Minjie; Kou, Shengzhong; Yan, Xingbin

    2014-11-01

    Graphene sheet (GS)-ionic liquid (IL) supercapacitors are receiving intense interest because their specific energy density far exceeds that of GS-aqueous electrolytes supercapacitors. The electrochemical properties of ILs mainly depend on their diverse ions, especially anions. Therefore, identifying suitable IL electrolytes for GSs is currently one of the most important tasks. The electrochemical behavior of GSs in a series of ILs composed of 1-ethyl-3-methylimidazolium cation (EMIM(+)) with different anions is systematically studied. Combined with the formula derivation and building models, it is shown that the viscosity, ion size, and molecular weight of ILs affect the electrical conductivity of ILs, and thus, determine the electrochemical performances of GSs. Because the EMIM-dicyanamide IL has the lowest viscosity, ion size, and molecular weight, GSs in it exhibit the highest specific capacitance, smallest resistance, and best rate capability. In addition, because the tetrafluoroborate anion (BF4(-)) has the best electrochemical stability, the GS-[EMIM][BF4] supercapacitor has the widest potential window, and thus, displays the largest energy density. These results may provide valuable information for selecting appropriate ILs and designing high-performance GS-IL supercapacitors to meet different needs.

  4. Application of adult stem cells in neural tissue engineering

    Institute of Scientific and Technical Information of China (English)

    Lihong Piao; Wei Wang

    2006-01-01

    OBJECTTIVE:To investigate the progress in finding,isolation and culture.proliferation and differentiation,and application in neural tissue engineering of adult stem cells(ASCs).DATA SOURCES:Using the terms"adult stem cells,nerve,tissue engineering".we searched the PubMed for adult stem ceils-related studies published in English from January 2001 to August 2006.Meanwhile,we also performed a China National Knowledge Infrastructure(CNKI)search for homochronous correlative literatures on the computer by inputting the terms"adult stem cells,nerve,tissue engineering"in Chinese.texts were searched for.Inclusive criteria:①Literatures about the sources,distribution,culture.proliferation and differentiation.and application in the repair of neural ASCs by tissue engineering.②Articles recommended either by randomized.blind or by other methods were not excluded.Exclusive criteria:①Embryonic stem cells.②Review,repetitive study,case report,Meta analysis. DATA EXTRACTION:Totally 1 278 articles related to ASCs were collected,32 were involved and the other 1 246 were excluded. DATA SYNTHESIS:Adult stem cell has the ability of self-renewal.unceasing proliferation and transdifferentiation.It has wide source,which does not involved in ethical problems.It has advantages over embryonic stem cell.Studies on the isolation and culture,induction and differentiation and application in neural ASCs by tissue engineering contribute to obtaining considerable ASCs,so as to provide experimental and theoretical bases for CONCLUSION:ASCs play a very important role in neural tissue engineering.

  5. Pressure cell engine - engine of the future?; Der Druckzellenmotor - die Motor-Alternative der Zukunft ?

    Energy Technology Data Exchange (ETDEWEB)

    Platzhoff, A. [Hochschule Wismar, Fachbereich Maschinenbau, Verfahrens- und Umwelttechnik (Germany); Reitz, J. [Initiativkreis Druckzellenmotor e.V., Heilbronn (Germany); Windisch, H. [Fachhochschule Heilbronn (Germany); Mueller, H.

    2004-07-01

    Can the growing demand for inexpensive mobile or steady state traction units still be met in 50 years? Limited resources of crude oil and changes of the earth climate by an increasing greenhouse gas pollution are calling the established stroke piston engine more and more into question. Now an evolutionary method of resolution was made out of characteristics from the Otto-, the Diesel-, the Wankel engine and the gas turbine. The new ''Druckzellen-Motor DZM'' (Pressure Cell Engine) is a thermodynamical engine, working after the basic Otto-engine rules, but significantly enhancing efficiency by functionally separating the single working processes into dedicated function units. The compression ratio and the expansion ratio are independently variable from each other. The continous isochorous combustion in a thermal accumulator only requires a low quality in fuel conditioning. Starting the engine from zero r.p.m. can be achieved by the charged thermal accumulator at maximum torque similar to a steam engine or a DC motor. (orig.)

  6. Animal and plant stem cells concepts, propagation and engineering

    CERN Document Server

    Pavlović, Mirjana

    2017-01-01

    This book provides a multifaceted look into the world of stem cells and explains the similarities and differences between plant and human stem cells. It explores the intersection between animals and plants and explains their cooperative role in bioengineering studies. The book treats both theoretical and practical aspects of stem cell research. It covers the advantages and limitations of many common applications related to stem cells: their sources, categories, engineering of these cells, reprogramming of their functions, and their role as novel cellular therapeutic approach. Written by experts in the field, the book focuses on aspects of stem cells ranging from expansion-propagation to metabolic reprogramming. It introduces the emergence of cancer stem cells and different modalities in targeted cancer stem cell therapies. It is a valuable source of fresh information for academics and researchers, examining molecular mechanisms of animal and plant stem cell regulation and their usage for therapeutic applicati...

  7. Genetically modified cells in regenerative medicine and tissue engineering.

    Science.gov (United States)

    Sheyn, Dima; Mizrahi, Olga; Benjamin, Shimon; Gazit, Zulma; Pelled, Gadi; Gazit, Dan

    2010-06-15

    Regenerative medicine appears to take as its patron, the Titan Prometheus, whose liver was able to regenerate daily, as the field attempts to restore lost, damaged, or aging cells and tissues. The tremendous technological progress achieved during the last decade in gene transfer methods and imaging techniques, as well as recent increases in our knowledge of cell biology, have opened new horizons in the field of regenerative medicine. Genetically engineered cells are a tool for tissue engineering and regenerative medicine, albeit a tool whose development is fraught with difficulties. Gene-and-cell therapy offers solutions to severe problems faced by modern medicine, but several impediments obstruct the path of such treatments as they move from the laboratory toward the clinical setting. In this review we provide an overview of recent advances in the gene-and-cell therapy approach and discuss the main hurdles and bottlenecks of this approach on its path to clinical trials and prospective clinical practice.

  8. Engineering three-dimensional cell mechanical microenvironment with hydrogels.

    Science.gov (United States)

    Huang, Guoyou; Wang, Lin; Wang, Shuqi; Han, Yulong; Wu, Jinhui; Zhang, Qiancheng; Xu, Feng; Lu, Tian Jian

    2012-12-01

    Cell mechanical microenvironment (CMM) significantly affects cell behaviors such as spreading, migration, proliferation and differentiation. However, most studies on cell response to mechanical stimulation are based on two-dimensional (2D) planar substrates, which cannot mimic native three-dimensional (3D) CMM. Accumulating evidence has shown that there is a significant difference in cell behavior in 2D and 3D microenvironments. Among the materials used for engineering 3D CMM, hydrogels have gained increasing attention due to their tunable properties (e.g. chemical and mechanical properties). In this paper, we provide an overview of recent advances in engineering hydrogel-based 3D CMM. Effects of mechanical cues (e.g. hydrogel stiffness and externally induced stress/strain in hydrogels) on cell behaviors are described. A variety of approaches to load mechanical stimuli in 3D hydrogel-based constructs are also discussed.

  9. Stem Cells and Scaffolds for Vascularizing Engineered Tissue Constructs

    Science.gov (United States)

    Luong, E.; Gerecht, S.

    The clinical impact of tissue engineering depends upon our ability to direct cells to form tissues with characteristic structural and mechanical properties from the molecular level up to organized tissue. Induction and creation of functional vascular networks has been one of the main goals of tissue engineering either in vitro, for the transplantation of prevascularized constructs, or in vivo, for cellular organization within the implantation site. In most cases, tissue engineering attempts to recapitulate certain aspects of normal development in order to stimulate cell differentiation and functional tissue assembly. The induction of tissue growth generally involves the use of biodegradable and bioactive materials designed, ideally, to provide a mechanical, physical, and biochemical template for tissue regeneration. Human embryonic stem cells (hESCs), derived from the inner cell mass of a developing blastocyst, are capable of differentiating into all cell types of the body. Specifically, hESCs have the capability to differentiate and form blood vessels de novo in a process called vasculogenesis. Human ESC-derived endothelial progenitor cells (EPCs) and endothelial cells have substantial potential for microvessel formation, in vitro and in vivo. Human adult EPCs are being isolated to understand the fundamental biology of how these cells are regulated as a population and to explore whether these cells can be differentiated and reimplanted as a cellular therapy in order to arrest or even reverse damaged vasculature. This chapter focuses on advances made toward the generation and engineering of functional vascular tissue, focusing on both the scaffolds - the synthetic and biopolymer materials - and the cell sources - hESCs and hEPCs.

  10. Silicon-on ceramic process. Silicon sheet growth and device development for the large-area silicon sheet and cell development tasks of the low-cost solar array project. Quarterly report No. 12, April 2, 1979-June 29, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W.; Zook, J.D.; Heaps, J.D.; Grung, B.L.; Koepke, B.; Schuldt, S.B.

    1979-07-31

    The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon. We plan to do this by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. During the quarter, significant progress was demonstrated in several areas: (1) a 10-cm/sup 2/ cell having 9.9 percent conversion efficiency (AM1, AR) was fabricated; (2) the Honeywall-sponsored SCIM coating development succeeded in producing a 225-cm/sup 2/ layer of sheet silicon (18 inches x 2 inches); and (3) 100 ..mu..m-thick coatings at pull speed of 0.15 cm/sec wer$obta9ned, although apoproximately 50 percent of the layer exhibited dendritic growth. Other results and accomplishments during the quarter are reported in detail. (WHK)

  11. Fabrication of a carbon nanofiber sheet as a micro-porous layer for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Qiongjuan; Wang, Jiong; Lu, Yonggen [College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Biao; Wang, Huaping [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2010-12-15

    A carbon nanofiber sheet (CNFS) has been prepared by electrospinning, stabilisation and subsequent carbonisation processes. Imaging with scanning electron microscope (SEM) indicates that the CNFS is formed by nonwoven nanofibers with diameters between 400 and 700 nm. The CNFS, with its three-dimensional pores, shows excellent electrical conductivity and hydrophobicity. In addition, it is found that the CNFS can be successfully applied as a micro-porous layer (MPL) in the cathode gas diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC). The GDL with the CNFS as a MPL has higher gas permeability than a conventional GDL. Moreover, the resultant cathode GDL exhibits excellent fuel cell performance with a higher peak power density than that of a cathode GDL fabricated with a conventional MPL under the same test condition. (author)

  12. Natural Polymer-Cell Bioconstructs for Bone Tissue Engineering.

    Science.gov (United States)

    Titorencu, Irina; Albu, Madalina Georgiana; Nemecz, Miruna; Jinga, Victor V

    2017-01-01

    The major goal of bone tissue engineering is to develop bioconstructs which substitute the functionality of damaged natural bone structures as much as possible if critical-sized defects occur. Scaffolds that mimic the structure and composition of bone tissue and cells play a pivotal role in bone tissue engineering applications. First, composition, properties and in vivo synthesis of bone tissue are presented for the understanding of bone formation. Second, potential sources of osteoprogenitor cells have been investigated for their capacity to induce bone repair and regeneration. Third, taking into account that the main property to qualify one scaffold as a future bioconstruct for bone tissue engineering is the biocompatibility, the assessments which prove it are reviewed in this paper. Forth, various types of natural polymer- based scaffolds consisting in proteins, polysaccharides, minerals, growth factors etc, are discussed, and interaction between scaffolds and cells which proved bone tissue engineering concept are highlighted. Finally, the future perspectives of natural polymer-based scaffolds for bone tissue engineering are considered.

  13. Engineering aspects of nitrification with immobilized cells.

    NARCIS (Netherlands)

    Hunik, J.H.

    1993-01-01

    Several aspects of a nitrification process with artificially immobilized cells in an airlift loop reactor have been investigated and are described in this thesis. In chapter 1 an overview of immobilization methods, suitable reactors, modelling, small-scaleapplications and scale-up strategy is given.

  14. Site-Specific Genome Engineering in Human Pluripotent Stem Cells

    Science.gov (United States)

    Merkert, Sylvia; Martin, Ulrich

    2016-01-01

    The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies. PMID:27347935

  15. Site-Specific Genome Engineering in Human Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Sylvia Merkert

    2016-06-01

    Full Text Available The possibility to generate patient-specific induced pluripotent stem cells (iPSCs offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies.

  16. Engineering Replacement Tissues with Amniotic Stem Cells

    Science.gov (United States)

    2012-10-01

    chondrogenic conditions (2D) formed tight nodes after 14 days. From left to right, nodes stained positive for alcian blue, safranin -O, and collagen II. 3...potential (alcian blue, safranin -O, collagen II staining) and colony forming ability were established (Figure 2). We were able to expand the cell...groups appear to be negative for Safranin -O stain (Figure 16) and weakly positive for alcian blue stain (Figure 17). Upon examination at a higher

  17. Engineered CHO cells for production of diverse, homogeneous glycoproteins

    DEFF Research Database (Denmark)

    Yang, Zhang; Wang, Shengjun; Halim, Adnan;

    2015-01-01

    genes controlling N-glycosylation in CHO cells and constructed a design matrix that facilitates the generation of desired glycosylation, such as human-like alpha 2,6-linked sialic acid capping. This engineering approach will aid the production of glycoproteins with improved properties and therapeutic...

  18. Mammalian designer cells: Engineering principles and biomedical applications.

    Science.gov (United States)

    Xie, Mingqi; Fussenegger, Martin

    2015-07-01

    Biotechnology is a widely interdisciplinary field focusing on the use of living cells or organisms to solve established problems in medicine, food production and agriculture. Synthetic biology, the science of engineering complex biological systems that do not exist in nature, continues to provide the biotechnology industry with tools, technologies and intellectual property leading to improved cellular performance. One key aspect of synthetic biology is the engineering of deliberately reprogrammed designer cells whose behavior can be controlled over time and space. This review discusses the most commonly used techniques to engineer mammalian designer cells; while control elements acting on the transcriptional and translational levels of target gene expression determine the kinetic and dynamic profiles, coupling them to a variety of extracellular stimuli permits their remote control with user-defined trigger signals. Designer mammalian cells with novel or improved biological functions not only directly improve the production efficiency during biopharmaceutical manufacturing but also open the door for cell-based treatment strategies in molecular and translational medicine. In the future, the rational combination of multiple sets of designer cells could permit the construction and regulation of higher-order systems with increased complexity, thereby enabling the molecular reprogramming of tissues, organisms or even populations with highest precision.

  19. Interface engineering of Graphene-Silicon heterojunction solar cells

    Science.gov (United States)

    Xu, Dikai; Yu, Xuegong; Yang, Lifei; Yang, Deren

    2016-11-01

    Graphene has attracted great research interests due to its unique mechanical, electrical and optical properties, which opens up a huge number of opportunities for applications. Recently, Graphene-Silicon (Grsbnd Si) solar cell has been recognized as one interesting candidate for the future photovoltaic. Since the first Grsbnd Si solar cell reported in 2010, Grsbnd Si solar cell has been intensively investigated and the power converse efficiency (PCE) of it has been developed to 15.6%. This review presents and discusses current development of Grsbnd Si solar cell. Firstly, the basic concept and mechanism of Grsbnd Si solar cell are introduced. Then, several key technologies are introduced to improve the performance of Grsbnd Si solar cells, such as chemical doping, annealing, Si surface passivation and interlayer insertion. Particular emphasis is placed on strategies for Grsbnd Si interface engineering. Finally, new pathways and opportunities of "MIS-like structure" Grsbnd Si solar cells are described.

  20. Cell surface engineering of yeast for applications in white biotechnology.

    Science.gov (United States)

    Kuroda, Kouichi; Ueda, Mitsuyoshi

    2011-01-01

    Cell surface engineering is a promising strategy for the molecular breeding of whole-cell biocatalysts. By using this strategy, yeasts can be constructed by the cell surface display of functional proteins; these yeasts are referred to as arming yeasts. Because reactions using arming yeasts as whole-cell biocatalysts occur on the cell surface, materials that cannot enter the cell can be used as reaction substrates. Numerous arming yeasts have therefore been constructed for a wide range of uses such as biofuel production, synthesis of valuable chemicals, adsorption or degradation of environmental pollutants, recovery of rare metal ions, and biosensors. Here, we review the science of yeast cell surface modification as well as current applications and future opportunities.

  1. Dependence of lattice strain relaxation, absorbance, and sheet resistance on thickness in textured ZnO@B transparent conductive oxide for thin-film solar cell applications

    Directory of Open Access Journals (Sweden)

    Kuang-Yang Kou

    2016-01-01

    Full Text Available The interplay of surface texture, strain relaxation, absorbance, grain size, and sheet resistance in textured, boron-doped ZnO (ZnO@B, transparent conductive oxide (TCO materials of different thicknesses used for thin film, solar cell applications is investigated. The residual strain induced by the lattice mismatch and the difference in the thermal expansion coefficient for thicker ZnO@B is relaxed, leading to an increased surface texture, stronger absorbance, larger grain size, and lower sheet resistance. These experimental results reveal the optical and material characteristics of the TCO layer, which could be useful for enhancing the performance of solar cells through an optimized TCO layer.

  2. Investigation of solar cells fabricated on low-cost silicon sheet materials using 1 MeV electron irradiation

    Science.gov (United States)

    Kachare, A. H.; Hyland, S. L.; Garlick, G. F. J.

    1981-01-01

    The use of high energy electron irradiation is investigated as a controlled means to study in more detail the junction depletion layer processes of solar cells made on various low-cost silicon sheet materials. Results show that solar cells made on Czochralski grown silicon exhibit enhancement of spectral response in the shorter wavelength region when irradiated with high energy electrons. The base region damage can be reduced by subsequent annealing at 450 C which restores the degraded longer wavelength response, although the shorter wavelength enhancement persists. The second diode component of the cell dark forward bias current is also reduced by electron irradiation, while thermal annealing at 450 C without electron irradiation can also produce these same effects. Electron irradiation produces small changes in the shorter wavelength spectral responses and junction improvements in solar cells made on WEB, EFG, and HEM silicon. It is concluded that these beneficial effects on cell characteristics are due to the reduction of oxygen associated deep level recombination centers in the N(+) diffused layer and in the junction.

  3. Silicon-on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

    Science.gov (United States)

    Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

    1979-01-01

    The technical and economic feasibility of producing solar cell-quality silicon was investigated. This was done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress in the following areas was demonstrated: (1) fabricating a 10 sq cm cell having 9.9 percent conversion efficiency; (2) producing a 225 sq cm layer of sheet silicon; and (3) obtaining 100 microns thick coatings at pull speed of 0.15 cm/sec, although approximately 50 percent of the layer exhibited dendritic growth.

  4. 5D imaging via light sheet microscopy reveals cell dynamics during the eye-antenna disc primordium formation in Drosophila

    Science.gov (United States)

    Huang, Yu Shan; Ku, Hui Yu; Tsai, Yun Chi; Chang, Chin Hao; Pao, Sih Hua; Sun, Y. Henry; Chiou, Arthur

    2017-03-01

    5D images of engrailed (en) and eye gone (eyg) gene expressions during the course of the eye-antenna disc primordium (EADP) formation of Drosophila embryos from embryonic stages 13 through 16 were recorded via light sheet microscopy and analyzed to reveal the cell dynamics involved in the development of the EADP. Detailed analysis of the time-lapsed images revealed the process of EADP formation and its invagination trajectory, which involved an inversion of the EADP anterior-posterior axis relative to the body. Furthermore, analysis of the en-expression pattern in the EADP provided strong evidence that the EADP is derived from one of the en-expressing head segments.

  5. Effects of Sheet Resistance on mc-Si Selective Emitter Solar Cells Using Laser Opening and One-Step Diffusion

    Directory of Open Access Journals (Sweden)

    Sheng-Shih Wang

    2015-01-01

    Full Text Available In order to simplify process procedure and improve conversion efficiency (η, we present new steps of laser opening and one-step POCl3 diffusion to fabricate selective emitter (SE solar cells, in which heavily doped regions (HDR and lightly doped regions (LDR were formed simultaneously. For HDR, we divided six cells into two groups for POCl3 diffusion with sheet resistance (RS of 40 Ω/sq (for group A and 50 Ω/sq (for group B. The dry oxidation duration at a temperature of 850°C was 18, 25, and 35 min for the 3 different cells in each group. This created six SE samples with different RS pairings for the HDR and LDR. The optimal cell (sample SE2 with RS values of 40/81 Ω/Sq in HDR/LDR showed the best η of 16.20%, open circuit voltage (VOC of 612.52 mV, and fill factor (FF of 75.83%. The improvement ratios are 1.57% for η and 14.32% for external quantum efficiency (EQE as compared with those of the two-step diffusion process of our previous study. Moreover, the one-step laser opening process and omitting the step of removing the damage caused by laser ablation especially reduce chemistry pollution, thus showing ecofriendly process for use in industrial-scale production.

  6. Performance of a proton exchange membrane fuel cell stack with thermally conductive pyrolytic graphite sheets for thermal management

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Chih-Yung; Lin, Yu-Sheng; Lu, Chien-Heng [Department of Aeronautics and Astronautics, National Cheng-Kung University, Tainan 70101 (China)

    2009-04-15

    This work experimentally investigates the effects of the pyrolytic graphite sheets (PGS) on the performance and thermal management of a proton exchange membrane fuel cell (PEMFC) stack. These PGS with the features of light weight and high thermal conductivity serve as heat spreaders in the fuel cell stack for the first time to reduce the volume and weight of cooling systems, and homogenizes the temperature in the reaction areas. A PEMFC stack with an active area of 100 cm{sup 2} and 10 cells in series is constructed and used in this research. Five PGS of thickness 0.1 mm are cut into the shape of flow channels and bound to the central five cathode gas channel plates. Four thermocouples are embedded on the cathode gas channel plates to estimate the temperature variation in the stack. It is shown that the maximum power of the stack increase more than 15% with PGS attached. PGS improve the stack performance and alleviate the flooding problem at low cathode flow rates significantly. Results of this study demonstrate the feasibility of application of PGS to the thermal management of a small-to-medium-sized fuel cell stack. (author)

  7. Award-Winning Etching Process Cuts Solar Cell Costs (Revised) (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-05-01

    The NREL "black silicon" nanocatalytic wet-chemical etch is an inexpensive, one-step method to minimize reflections from crystalline silicon solar cells. The technology enables high-efficiency solar cells without the use of expensive antireflection coatings.

  8. Spatiotemporal control of cell-cell reversible interactions using molecular engineering

    Science.gov (United States)

    Shi, Peng; Ju, Enguo; Yan, Zhengqing; Gao, Nan; Wang, Jiasi; Hou, Jianwen; Zhang, Yan; Ren, Jinsong; Qu, Xiaogang

    2016-10-01

    Manipulation of cell-cell interactions has potential applications in basic research and cell-based therapy. Herein, using a combination of metabolic glycan labelling and bio-orthogonal click reaction, we engineer cell membranes with β-cyclodextrin and subsequently manipulate cell behaviours via photo-responsive host-guest recognition. With this methodology, we demonstrate reversible manipulation of cell assembly and disassembly. The method enables light-controllable reversible assembly of cell-cell adhesion, in contrast with previously reported irreversible effects, in which altered structure could not be reused. We also illustrate the utility of the method by designing a cell-based therapy. Peripheral blood mononuclear cells modified with aptamer are effectively redirected towards target cells, resulting in enhanced cell apoptosis. Our approach allows precise control of reversible cell-cell interactions and we expect that it will promote further developments of cell-based therapy.

  9. Interleukin 7-engineered stromal cells: a new approach for hastening naive T cell recruitment.

    Science.gov (United States)

    Di Ianni, Mauro; Del Papa, Beatrice; De Ioanni, Maria; Terenzi, Adelmo; Sportoletti, Paolo; Moretti, Lorenzo; Falzetti, Franca; Gaozza, Eugenia; Zei, Tiziana; Spinozzi, Fabrizio; Bagnis, Claude; Mannoni, Patrice; Bonifacio, Elisabetta; Falini, Brunangelo; Martelli, Massimo F; Tabilio, Antonio

    2005-06-01

    In this study we determined whether human stromal cells could be engineered with a retroviral vector carrying the interleukin 7 (IL-7) gene and investigated the effects on T cells in vitro and in vivo in a murine model. Transduced mesenchymal cells strongly express CD90 (98.15%), CD105 (87.6%), and STRO-1 (86.7%). IL-7 production was 16.37 (+/-2 SD) pg/ml, which remained stable for 60 days. In vitro-immunoselected naive T cells maintained the CD45RA+ CD45RO- naive phenotype (4.2 times more than controls) after 7 days of culture with IL-7-engineered stromal cells. The apoptosis rate (4.7%) of the naive T cells cultured with transduced stromal cells overlapped with that of freshly isolated cells. Immunohistological analysis detected stromal cells in bone marrow, spleen, and thymus. Cotransplantation of IL-7-engineered stromal cells with CD34+ cells improved engraftment in terms of CD45+ cells and significantly increased the CD3+ cell count in peripheral blood, bone marrow, and spleen. These data demonstrate the following: (1) human stromal cells can be transduced, generating a normal layer; (2) transduced stromal cells in vitro maintain the naive T cell phenotype; and (3) IL-7-transduced stromal cells in vivo home to lymphoid organs and produce sufficient IL-7 in loco, supporting T cell development in a cotransplantation model. Because of their efficient cytokine production and homing, IL-7-engineered stromal cells might be an ideal vehicle to hasten immunological reconstitution in T cell-depleted hosts.

  10. A Modified Porous Titanium Sheet Prepared by Plasma-Activated Sintering for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Yukimichi Tamaki

    2010-01-01

    Full Text Available This study aimed to develop a contamination-free porous titanium scaffold by a plasma-activated sintering within an originally developed TiN-coated graphite mold. The surface of porous titanium sheet with or without a coated graphite mold was characterized. The cell adhesion property of porous titanium sheet was also evaluated in this study. The peak of TiC was detected on the titanium sheet processed with the graphite mold without a TiN coating. Since the titanium fiber elements were directly in contact with the carbon graphite mold during processing, surface contamination was unavoidable event in this condition. The TiC peak was not detectable on the titanium sheet processed within the TiN-coated carbon graphite mold. This modified plasma-activated sintering with the TiN-coated graphite mold would be useful to fabricate a contamination-free titanium sheet. The number of adherent cells on the modified titanium sheet was greater than that of the bare titanium plate. Stress fiber formation and the extension of the cells were observed on the titanium sheets. This modified titanium sheet is expected to be a new tissue engineering material in orthopedic bone repair.

  11. Defect engineering in solar cell manufacturing and thin film solar cell development

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    During the last few years many defect engineering concepts were successfully applied to fabricate high efficiency silicon solar cells on low-cost substrates. Some of the research advances are described.

  12. Effect of the hydrophobic basal layer of thermoresponsive block co-polymer brushes on thermally-induced cell sheet harvest.

    Science.gov (United States)

    Matsuzaka, Naoki; Takahashi, Hironobu; Nakayama, Masamichi; Kikuchi, Akihiko; Okano, Teruo

    2012-01-01

    Thermoresponsive poly(benzyl methacrylate)-b-poly(N-isopropylacrylamide) (PBzMA-b-PIPAAm) block co-polymer brush surfaces were prepared by surface-initiated two-step reversible addition-fragmentation chain transfer radical (RAFT) polymerization. PBzMA brushes were fabricated on azoinitiator-immobilized glass substrates in the presence of dithiobenzoate (DTB) compound as a RAFT agent. The amount of grafted polymer was regulated by initial monomer concentrations. The second thermoresponsive blocks were added to the RAFT-related DTB groups located at PBzMA termini through the propagation of PIPAAm chains, resulting in formation of PBzMA-b-PIPAAm brushes. Surface characteristics of the block co-polymer brushes and its influence on thermally regulated cellular behavior were investigated using bovine carotid artery endothelial cells (BAECs), compared with PIPAAm brush surfaces. Cell adhesion/detachment behavior on thermoresponsive polymer brush surfaces significantly depended on their individual polymer architectures and chemical compositions of grafted polymers. Low-temperature treatment at 20°C, below the phase-transition temperature of PIPAAm, induced the spontaneous detachment of adhering cells from the PBzMA-b-PIPAAm brush surfaces with a higher rate than that from PIPAAm brush surfaces. In addition, the cell-repellent effect of the hydrophobic basal layer successfully accelerated for harvesting BAEC sheets from the block co-polymer brush surfaces. Unique features of thermoresponsive block co-polymer brush architectures can be applied to control cell-adhesion strength for enhancing cell adhesion or accelerating cell detachment.

  13. Genetic Engineering of Mesenchymal Stem Cells for Regenerative Medicine.

    Science.gov (United States)

    Nowakowski, Adam; Walczak, Piotr; Janowski, Miroslaw; Lukomska, Barbara

    2015-10-01

    Mesenchymal stem cells (MSCs), which can be obtained from various organs and easily propagated in vitro, are one of the most extensively used types of stem cells and have been shown to be efficacious in a broad set of diseases. The unique and highly desirable properties of MSCs include high migratory capacities toward injured areas, immunomodulatory features, and the natural ability to differentiate into connective tissue phenotypes. These phenotypes include bone and cartilage, and these properties predispose MSCs to be therapeutically useful. In addition, MSCs elicit their therapeutic effects by paracrine actions, in which the metabolism of target tissues is modulated. Genetic engineering methods can greatly amplify these properties and broaden the therapeutic capabilities of MSCs, including transdifferentiation toward diverse cell lineages. However, cell engineering can also affect safety and increase the cost of therapy based on MSCs; thus, the advantages and disadvantages of these procedures should be discussed. In this review, the latest applications of genetic engineering methods for MSCs with regenerative medicine purposes are presented.

  14. Developing Novel Therapeutic Approaches in Small Cell Lung Carcinoma Using Genetically Engineered Mouse Models and Human Circulating Tumor Cells

    Science.gov (United States)

    2015-10-01

    Using Genetically Engineered Mouse Models and Human Circulating Tumor Cells PRINCIPAL INVESTIGATOR: Jeffrey Engelman MD PhD CONTRACTING...SUBTITLE Developiing Novel Therapeutic Approaches in Small Cell Lung 5a. CONTRACT NUMBER Carcinoma Using Genetically Engineered Mouse Models and 5b...biomarkers. 15. SUBJECT TERMS Small cell lung cancer (SCLC), Genetically engineered mouse model (GEMM), BH3 mimetic, TORC inhibitor, Apoptosis

  15. Skin Tissue Engineering: Application of Adipose-Derived Stem Cells

    Science.gov (United States)

    Zimoch, Jakub; Biedermann, Thomas

    2017-01-01

    Perception of the adipose tissue has changed dramatically over the last few decades. Identification of adipose-derived stem cells (ASCs) ultimately transformed paradigm of this tissue from a passive energy depot into a promising stem cell source with properties of self-renewal and multipotential differentiation. As compared to bone marrow-derived stem cells (BMSCs), ASCs are more easily accessible and their isolation yields higher amount of stem cells. Therefore, the ASCs are of high interest for stem cell-based therapies and skin tissue engineering. Currently, freshly isolated stromal vascular fraction (SVF), which may be used directly without any expansion, was also assessed to be highly effective in treating skin radiation injuries, burns, or nonhealing wounds such as diabetic ulcers. In this paper, we review the characteristics of SVF and ASCs and the efficacy of their treatment for skin injuries and disorders.

  16. Silicon-on-ceramic process: silicon sheet growth and device development for the Large-Area Silicon Sheet and Cell Development Tasks of the Low-Cost Solar Array Project. Quarterly report No. 11, January 1-March 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W.; Zook, J.D.; Heaps, J.D.; Grung, B.L.; Koepke, B.; Schuldt, S.B.

    1979-04-30

    The purpose of the research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 12 percent or greater. By applying a graphite coating to one face of a ceramic substrate, molten silicon can be caused to wet only that graphite-coated face and produce uniform thin layers of large-grain polycrystalline silicon; thus, only a minimal quantity of silicon is consumed. A dip-coating method for putting silicon on ceramic (SOC) has been shown to produce solar-cell-quality sheet silicon. This method and a continuous coating process also being investigated have excellent scale-up potential which offers an outstanding, cost-effective way to manufacture large-area solar cells. Results and accomplishments are described.

  17. Preparation and characterization of mono-sheet bipolar membranes by pre-irradiation grafting method for fuel cell applications

    Science.gov (United States)

    Guan, Yingjie; Fang, Jun; Fu, Tao; Zhou, Huili; Wang, Xin; Deng, Zixiang; Zhao, Jinbao

    2016-09-01

    A new method for the preparation of the mono-sheet bipolar membrane applied to fuel cells was developed based on the pre-irradiation grafting technology. A series of bipolar membranes were successfully prepared by simultaneously grafting of styrene onto one side of the poly(ethylene-co-tetrafluoroethylene) base film and 1-vinylimidazole onto the opposite side, followed by the sulfonation and alkylation, respectively. The chemical structures and microstructures of the prepared membranes were investigated by ATR-FTIR and SEM-EDS. The TGA measurements demonstrated the prepared bipolar membranes have reasonable thermal stability. The ion exchange capacity, water uptake and ionic conductivity of the membranes were also characterized. The H2/O2 single fuel cells using these membranes were evaluated and revealed a maximum power density of 107 mW cm-2 at 35 °C with unhumidified hydrogen and oxygen. The preliminary performances suggested the great prospect of these membranes in application of bipolar membrane fuel cells.

  18. Patterning methods for polymers in cell and tissue engineering.

    Science.gov (United States)

    Kim, Hong Nam; Kang, Do-Hyun; Kim, Min Sung; Jiao, Alex; Kim, Deok-Ho; Suh, Kahp-Yang

    2012-06-01

    Polymers provide a versatile platform for mimicking various aspects of physiological extracellular matrix properties such as chemical composition, rigidity, and topography for use in cell and tissue engineering applications. In this review, we provide a brief overview of patterning methods of various polymers with a particular focus on biocompatibility and processability. The materials highlighted here are widely used polymers including thermally curable polydimethyl siloxane, ultraviolet-curable polyurethane acrylate and polyethylene glycol, thermo-sensitive poly(N-isopropylacrylamide) and thermoplastic and conductive polymers. We also discuss how micro- and nanofabricated polymeric substrates of tunable elastic modulus can be used to engineer cell and tissue structure and function. Such synergistic effect of topography and rigidity of polymers may be able to contribute to constructing more physiologically relevant microenvironment.

  19. Interfacial Engineering for Quantum-Dot-Sensitized Solar Cells.

    Science.gov (United States)

    Shen, Chao; Fichou, Denis; Wang, Qing

    2016-04-20

    Quantum-dot-sensitized solar cells (QDSCs) are promising solar-energy-conversion devices, as low-cost alternatives to the prevailing photovoltaic technologies. Compared with molecular dyes, nanocrystalline quantum dot (QD) light absorbers exhibit higher molar extinction coefficients and a tunable photoresponse. However, the power-conversion efficiencies (PCEs) of QDSCs are generally below 9.5 %, far behind their molecular sensitizer counterparts (up to 13 %). These low PCEs have been attributed to a large free-energy loss during sensitizer regeneration, energy loss during the charge-carrier transport and transfer processes, and inefficient charge separation at the QD/electrolyte interfaces, and various interfacial engineering strategies for enhancing the PCE and cell stability have been reported. Herein, we review recent progress in the interfacial engineering of QDSCs and discuss future prospects for the development of highly efficient and stable QDSCs.

  20. Silicon sheet with molecular beam epitaxy for high efficiency solar cells

    Science.gov (United States)

    Allen, F. G.

    1983-01-01

    The capabilities of the new technique of Molecular Beam Epitaxy (MBE) are applied to the growth of high efficiency silicon solar cells. Because MBE can provide well controlled doping profiles of any desired arbitrary design, including doping profiles of such complexity as built-in surface fields or tandem junction cells, it would appear to be the ideal method for development of high efficiency solar cells. It was proposed that UCLA grow and characterize silicon films and p-n junctions of MBE to determine whether the high crystal quality needed for solar cells could be achieved.

  1. Engineering novel cell surface chemistry for selective tumor cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, C.R. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    A common feature of many different cancers is the high expression level of the two monosaccharides sialic acid and fucose within the context of cell-surface associated glycoconjugates. A correlation has been made between hypersialylation and/or hyperfucosylation and the highly metastatic phenotype. Thus, a targeting strategy based on sialic acid or fucose expression would be a powerful tool for the development of new cancer cell-selective therapies and diagnostic agents. We have discovered that ketone groups can be incorporated metabolically into cell-surface associated sialic acids. The ketone is can be covalently ligated with hydrazide functionalized proteins or small molecules under physiological conditions. Thus, we have discovered a mechanism to selectively target hydrazide conjugates to highly sialylated cells such as cancer cells. Applications of this technology to the generation of novel cancer cell-selective toxins and MRI contrast reagents will be discussed, in addition to progress towards the use of cell surface fucose residues as vehicles for ketone expression.

  2. Genetic engineering of hematopoietic stem cells to generate invariant natural killer T cells.

    Science.gov (United States)

    Smith, Drake J; Liu, Siyuan; Ji, Sunjong; Li, Bo; McLaughlin, Jami; Cheng, Donghui; Witte, Owen N; Yang, Lili

    2015-02-03

    Invariant natural killer T (iNKT) cells comprise a small population of αβ T lymphocytes. They bridge the innate and adaptive immune systems and mediate strong and rapid responses to many diseases, including cancer, infections, allergies, and autoimmunity. However, the study of iNKT cell biology and the therapeutic applications of these cells are greatly limited by their small numbers in vivo (∼0.01-1% in mouse and human blood). Here, we report a new method to generate large numbers of iNKT cells in mice through T-cell receptor (TCR) gene engineering of hematopoietic stem cells (HSCs). We showed that iNKT TCR-engineered HSCs could generate a clonal population of iNKT cells. These HSC-engineered iNKT cells displayed the typical iNKT cell phenotype and functionality. They followed a two-stage developmental path, first in thymus and then in the periphery, resembling that of endogenous iNKT cells. When tested in a mouse melanoma lung metastasis model, the HSC-engineered iNKT cells effectively protected mice from tumor metastasis. This method provides a powerful and high-throughput tool to investigate the in vivo development and functionality of clonal iNKT cells in mice. More importantly, this method takes advantage of the self-renewal and longevity of HSCs to generate a long-term supply of engineered iNKT cells, thus opening up a new avenue for iNKT cell-based immunotherapy.

  3. Magnetically labeled cells with surface-modified fe3 o4 spherical and rod-shaped magnetic nanoparticles for tissue engineering applications.

    Science.gov (United States)

    Gil, Sara; Correia, Clara R; Mano, João F

    2015-04-22

    Magnetically targeted cells with internalized magnetic nanoparticles (MNPs) could allow the success of cell transplantation and cell-based therapies, overcoming low cell retention that occurs when delivering cells by intravenous or local injection. Upon magnetization, these cells could then accumulate and stimulate the regeneration of the tissue in situ. Magnetic targeting of cells requires a detailed knowledge between interactions of engineered nanomaterials and cells, in particular the influence of shape and surface functionalization of MNPs. For the first time, cellular internalization of amino surface-modified iron oxide nanoparticles of two different shapes (nanospheres or nanorods) is studied. MNPs show high cellular uptake and labeled cells could exhibit a strong reaction with external magnetic fields. Compared to nanorods, nanospheres show better internalization efficiency, and labeled cells exhibit strong transportation reaction with external magnetic fields. Contiguous viable cell-sheets are developed by magnetic-force-based tissue engineering. The results confirm that the developed magnetic-responsive nano-biomaterials have potential applicability in tissue engineering or cellular therapies.

  4. Photobiology Research Laboratory (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-06-01

    This fact sheet provides information about Photobiology Research Laboratory capabilities and applications at NREL. The photobiology group's research is in four main areas: (1) Comprehensive studies of fuel-producing photosynthetic, fermentative, and chemolithotrophic model microorganisms; (2) Characterization and engineering of redox enzymes and proteins for fuel production; (3) Genetic and pathway engineering of model organisms to improve production of hydrogen and hydrocarbon fuels; and (4) Studies of nanosystems using biological and non-biological materials in hybrid generation. NREL's photobiology research capabilities include: (1) Controlled and automated photobioreactors and fermenters for growing microorganisms under a variety of environmental conditions; (2) High-and medium-throughput screening of H{sub 2}-producing organisms; (3) Homologous and heterologous expression, purification, and biochemical/biophysical characterization of redox enzymes and proteins; (4) Qualitative and quantitative analyses of gases, metabolites, carbohydrates, lipids, and proteins; (5) Genetic and pathway engineering and development of novel genetic toolboxes; and (6) Design and spectroscopic characterization of enzyme-based biofuel cells and energy conversion nanodevices.

  5. Stem Cell-assisted Approaches for Cartilage Tissue Engineering

    OpenAIRE

    Park, In-Kyu; Cho, Chong-Su

    2010-01-01

    The regeneration of damaged articular cartilage remains challenging due to its poor intrinsic capacity for repair. Tissue engineering of articular cartilage is believed to overcome the current limitations of surgical treatment by offering functional regeneration in the defect region. Selection of proper cell sources and ECM-based scaffolds, and incorporation of growth factors or mechanical stimuli are of primary importance to successfully produce artificial cartilage for tissue repair. When d...

  6. Enamel tissue engineering using subcultured enamel organ epithelial cells in combination with dental pulp cells.

    Science.gov (United States)

    Honda, Masaki J; Shinmura, Yuka; Shinohara, Yoshinori

    2009-01-01

    We describe a strategy for the in vitro engineering of enamel tissue using a novel technique for culturing enamel organ epithelial (EOE) cells isolated from the enamel organ using 3T3-J2 cells as a feeder layer. These subcultured EOE cells retain the capacity to produce enamel structures over a period of extended culture. In brief, enamel organs from 6-month-old porcine third molars were dissociated into single cells and subcultured on 3T3-J2 feeder cell layers. These subcultured EOE cells were then seeded onto a collagen sponge in combination with primary dental pulp cells isolated at an early stage of crown formation, and these constructs were transplanted into athymic rats. After 4 weeks, complex enamel-dentin structures were detected in the implants. These results show that our culture technique maintained ameloblast lineage cells that were able to produce enamel in vivo. This novel subculture technique provides an important tool for tooth tissue engineering.

  7. Engineering the Interface Between Inorganic Materials and Cells

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, David

    2014-05-31

    To further optimize cell function in hybrid “living materials”, it would be advantageous to render mammalian cells responsive to novel “orthogonal” cues, i.e. signals they would not ordinarily respond to but that can be engineered to feed into defined intracellular signaling pathways. We recently developed an optogenetic method, based on A. thaliana Cry2, for rapid and reversible protein oligomerization in response to blue light. We also demonstrated the ability to use this method to channel the light input into several defined signaling pathways, work that will enhance communication between inorganic devices and living systems.

  8. Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells.

    Science.gov (United States)

    Zhao, Yixin; Zhu, Kai

    2014-12-04

    Organic and inorganic hybrid perovskites (e.g., CH3NH3PbI3) have emerged as a revolutionary class of light-absorbing semiconductors that has demonstrated a rapid increase in efficiency within a few years of active research. Controlling perovskite morphology and composition has been found critical to developing high-performance perovskite solar cells. The recent development of solution chemistry engineering has led to fabrication of greater than 15-17%-efficiency solar cells by multiple groups, with the highest certified 17.9% efficiency that has significantly surpassed the best-reported perovskite solar cell by vapor-phase growth. In this Perspective, we review recent progress on solution chemistry engineering processes and various control parameters that are critical to the success of solution growth of high-quality perovskite films. We discuss the importance of understanding the impact of solution-processing parameters and perovskite film architectures on the fundamental charge carrier dynamics in perovskite solar cells. The cost and stability issues of perovskite solar cells will also be discussed.

  9. Engineered microtopographies and surface chemistries direct cell attachment and function

    Science.gov (United States)

    Magin, Chelsea Marie

    Harrison, in 1914, first recognized that cells respond to physicochemical cues such as substratum topography when he observed that fibroblasts elongated while cultured on spider silk. Recently, techniques developed in the micro-electronics industry have been used to create molds for producing microscaled topographies with various shapes and spatial arrangements. Although these patterning techniques are well-established, very little is known about the mechanisms underlying cell sensing and response to microtopographies. In this work cellular micro-environments with varying surface topographies and chemistries were evaluated with marine organisms and mammalian cells to investigate cellular sensing and response. Biofouling---the accumulation of micro-organisms, plants, and animals on submerged surfaces---is an environmental and economic concern. Engineered topographies, replicated in polydimethylsiloxane elastomer (PDMSe) and functionalized poly(ethylene glycol)-dimethacrylate (PEGDMA) hydrogels, were evaluated for inhibition of marine fouling organism attachment. Microtopographies replicated in PDMSe inhibited attachment of the marine bacterium, Cobetia marina up to 99% versus smooth. The average normalized attachment densities of cells of C. marina and zoospores of the green algae Ulva on PDMSe topographies scaled inversely with the Engineered Roughness Index (ERIII), a representation of surface energy. Attachment densities of Ulva from four assays and C. marina from two growth phases to PDMSe surfaces scaled inversely with one equation: ERI II multiplied by the Reynolds number of the organism (Re) (R 2 = 0.77). The same microtopographies created in PDMSe reduced the initial attachment density and attachment strength of cells of the diatoms Navicula incerta and Seminavis robusta compared to smooth PDMSe. The average normalized attachment density of Navicula after exposure to shear stress (48 Pa) was correlated with the contact area between the diatom and a

  10. Silicon-on-ceramic coating process. Silicon sheet growth development for the Large-Area Silicon Sheet and Cell Development Tasks of the Low-Cost Silicon Solar Array Project. Quarterly report No. 8, December 28, 1977--March 28, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, P.W. Zook, J.D.; Heaps, J D; Maclolek, R B; Koepke, B; Butter, C D; Schult, S B

    1978-04-20

    A research program to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon is described. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 12 percent or greater. By applying a graphite coating to one face of a ceramic substrate, molten silicon can be caused to wet only that graphite-coated face and produce uniform thin layers of large-grain polycrystalline silicon; thus, only a minimal quantity of silicon is consumed. A dip-coating method for putting silicon on ceramic (SOC) has been shown to produce solar-cell-quality sheet silicon. This method and a continuous coating process also being investigated have excellent scale-up potential which offers an outstanding cost-effective way to manufacture large-area solar cells. A variety of ceramic materials have been dip-coated with silicon. The investigation has shown that mullite substrates containing an excess of SiO/sub 2/ best match the thermal expansion coefficient of silicon and hence produce the best SOC layers. With such substrates, smooth and uniform silicon layers 25 cm/sup 2/ in area have been achieved with single-crystal grains as large as 4 mm in width and several cm in length. Solar cells with areas from 1 to 10 cm/sup 2/ have been fabricated from material withas-grown surface. Recently, an antireflection (AR) coating has been applied to SOC cells. Conversion efficiencies greater than 9% have been achieved without optimizing series resistance characteristics. Such cells typically have open-circuit voltages and short-circuit current densities of 0.51 V and 20 mA/cm/sup 2/, respectively.

  11. NREL Invention Speeds Solar Cell Quality Testing for Industry (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-08-01

    A solid-state optical system, invented by the National Renewable Energy Laboratory (NREL), measures solar cell quantum efficiency (QE) in less than a second, enabling a suite of new capabilities for solar cell manufacturers. QE is a measurement of how cells respond to light across the solar spectrum, but traditional methods for measuring QE had been too slow, limiting its application to small samples pulled from the production line and analyzed in laboratories. NREL's technique, commercialized by Tau Science as the FlashQE(TM) system, uses a solid-state light source, synchronized electronics, and advanced mathematical analysis to parallel-process QE data in a tiny fraction of the time required by the current method, allowing its use on every solar cell passing through a production line.

  12. Silicon on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

    Science.gov (United States)

    Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Pickering, C.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

    1979-01-01

    The technical and economic feasibility of producing solar cell quality sheet silicon was investigated. It was hoped this could be done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Work was directed towards the solution of unique cell processing/design problems encountered with the silicon-ceramic (SOC) material due to its intimate contact with the ceramic substrate. Significant progress was demonstrated in the following areas; (1) the continuous coater succeeded in producing small-area coatings exhibiting unidirectional solidification and substatial grain size; (2) dip coater succeeded in producing thick (more than 500 micron) dendritic layers at coating speeds of 0.2-0.3 cm/sec; and (3) a standard for producing total area SOC solar cells using slotted ceramic substrates was developed.

  13. Modeling crawling cell movement on soft engineered substrates.

    Science.gov (United States)

    Löber, Jakob; Ziebert, Falko; Aranson, Igor S

    2014-03-07

    Self-propelled motion, emerging spontaneously or in response to external cues, is a hallmark of living organisms. Systems of self-propelled synthetic particles are also relevant for multiple applications, from targeted drug delivery to the design of self-healing materials. Self-propulsion relies on the force transfer to the surrounding. While self-propelled swimming in the bulk of liquids is fairly well characterized, many open questions remain in our understanding of self-propelled motion along substrates, such as in the case of crawling cells or related biomimetic objects. How is the force transfer organized and how does it interplay with the deformability of the moving object and the substrate? How do the spatially dependent traction distribution and adhesion dynamics give rise to complex cell behavior? How can we engineer a specific cell response on synthetic compliant substrates? Here we generalize our recently developed model for a crawling cell by incorporating locally resolved traction forces and substrate deformations. The model captures the generic structure of the traction force distribution and faithfully reproduces experimental observations, like the response of a cell on a gradient in substrate elasticity (durotaxis). It also exhibits complex modes of cell movement such as "bipedal" motion. Our work may guide experiments on cell traction force microscopy and substrate-based cell sorting and can be helpful for the design of biomimetic "crawlers" and active and reconfigurable self-healing materials.

  14. Engineering molecular circuits using synthetic biology in mammalian cells.

    Science.gov (United States)

    Wieland, Markus; Fussenegger, Martin

    2012-01-01

    Synthetic biology has made significant leaps over the past decade, and it now enables rational and predictable reprogramming of cells to conduct complex physiological activities. The bases for cellular reprogramming are mainly genetic control components affecting gene expression. A huge variety of these modules, ranging from engineered fusion proteins regulating transcription to artificial RNA devices affecting translation, is available, and they often feature a highly modular scaffold. First endeavors to combine these modules have led to autoregulated expression systems and genetic cascades. Analogous to the rational engineering of electronic circuits, the existing repertoire of artificial regulatory elements has further enabled the ambitious reprogramming of cells to perform Boolean calculations or to mimic the oscillation of circadian clocks. Cells harboring synthetic gene circuits are not limited to cell culture, as they have been successfully implanted in animals to obtain tailor-made therapeutics that have made it possible to restore urea or glucose homeostasis as well as to offer an innovative approach to artificial insemination.

  15. Genetic engineering of stem cells for enhanced therapy.

    Science.gov (United States)

    Nowakowski, Adam; Andrzejewska, Anna; Janowski, Miroslaw; Walczak, Piotr; Lukomska, Barbara

    2013-01-01

    Stem cell therapy is a promising strategy for overcoming the limitations of current treatment methods. The modification of stem cell properties may be necessary to fully exploit their potential. Genetic engineering, with an abundance of methodology to induce gene expression in a precise and well-controllable manner, is particularly attractive for this purpose. There are virus-based and non-viral methods of genetic manipulation. Genome-integrating viral vectors are usually characterized by highly efficient and long-term transgene expression, at a cost of safety. Non-integrating viruses are also highly efficient in transduction, and, while safer, offer only a limited duration of transgene expression. There is a great diversity of transfectable forms of nucleic acids; however, for efficient shuttling across cell membranes, additional manipulation is required. Both physical and chemical methods have been employed for this purpose. Stem cell engineering for clinical applications is still in its infancy and requires further research. There are two main strategies for inducing transgene expression in therapeutic cells: transient and permanent expression. In many cases, including stem cell trafficking and using cell therapy for the treatment of rapid-onset disease with a short healing process, transient transgene expression may be a sufficient and optimal approach. For that purpose, mRNA-based methods seem ideally suited, as they are characterized by a rapid, highly efficient transfection, with outstanding safety. Permanent transgene expression is primarily based on the application of viral vectors, and, due to safety concerns, these methods are more challenging. There is active, ongoing research toward the development of non-viral methods that would induce permanent expression, such as transposons and mammalian artificial chromosomes.

  16. NREL Explores Earth-Abundant Materials for Future Solar Cells (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-10-01

    Researchers at the National Renewable Energy Laboratory (NREL) are using a theory-driven technique - sequential cation mutation - to understand the nature and limitations of promising solar cell materials that can replace today's technologies. Finding new materials that use Earth-abundant elements and are easily manufactured is important for large-scale solar electricity deployment.

  17. Adhesion, resistivity and structural, optical properties of molybdenum on steel sheet coated with barrier layer done by sol–gel for CIGS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Amouzou, Dodji, E-mail: dodji.amouzou@fundp.ac.be [Research Centre in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Rue de Bruxelles 61, 5000 Namur (Belgium); Dumont, Jacques [Research Centre in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Rue de Bruxelles 61, 5000 Namur (Belgium); Fourdrinier, Lionel; Richir, Jean-Baptiste; Maseri, Fabrizio [CRM-Group, Boulevard de Colonster, B 57, 4000 Liège (Belgium); Sporken, Robert [Research Centre in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Rue de Bruxelles 61, 5000 Namur (Belgium)

    2013-03-01

    Molybdenum films are investigated on stainless steel substrates coated with polysilazane based sol–gel and SiO{sub x} layers for flexible CIGS solar cell applications. Thermal stability of the multilayer has been studied. The thickness of polysilazane films are significantly reduced (17%) after heat treatment suggesting a thermal degradation. Four different microstructures were found for Mo films by varying argon total pressure from 2.6 × 10{sup −1} Pa to 2.6 Pa. It was shown that continuous films, low sheet resistance (0.5 Ω/□) and well facetted grains can be achieved when Mo films are deposited on heated substrates at homologous temperature, T of 0.2. - Highlights: ► Steel sheet is functionalized for Cu[Inx,Ga(1 − x)Se2] solar cells. ► Varying deposition pressure impacts the microstructure of Mo films. ► High thermal stability of the sol gel based barrier layer has been investigated. ► Low sheet resistance and continuous Mo films have been obtained at 550°C. ► Thermal stability of functionalized steel sheets at 550°C has been investigated.

  18. Stem Cell-assisted Approaches for Cartilage Tissue Engineering.

    Science.gov (United States)

    Park, In-Kyu; Cho, Chong-Su

    2010-05-01

    The regeneration of damaged articular cartilage remains challenging due to its poor intrinsic capacity for repair. Tissue engineering of articular cartilage is believed to overcome the current limitations of surgical treatment by offering functional regeneration in the defect region. Selection of proper cell sources and ECM-based scaffolds, and incorporation of growth factors or mechanical stimuli are of primary importance to successfully produce artificial cartilage for tissue repair. When designing materials for cartilage tissue engineering, biodegradability and biocompatibility are the key factors in selecting material candidates, for either synthetic or natural polymers. The unique environment of cartilage makes it suitable to use a hydrogel with high water content in the cross-linked or thermosensitive (injectable) form. Moreover, design of composite scaffolds from two polymers with complementary physicochemical and biological properties has been explored to provide residing chondrocytes with a combination of the merits that each component contributes.

  19. Metabolically engineered cells for the production of polyunsaturated fatty acids

    DEFF Research Database (Denmark)

    2005-01-01

    The present invention relates to the construction and engineering of cells, more particularly microorganisms for producing PUFAs with four or more double bonds from non-fatty acid substrates through heterologous expression of an oxygen requiring pathway. The invention especially involves...... improvement of the PUFA content in the host organism through fermentation optimization, e.g. decreasing the temperature and/or designing an optimal medium, or through improving the flux towards fatty acids by metabolic engineering, e.g. through over-expression of fatty acid synthases, over-expression of other...... enzymes involved in biosynthesis of the precursor for PUFAs, or codon optimization of the heterologous genes, or expression of heterologous enzymes involved in the biosynthesis of the precursor for PUFAs....

  20. New Fabrication Method Improves the Efficiency and Economics of Solar Cells (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    Synthetic fabrication strategy optimizes the illumination geometry and transport properties of dye-sensitized solar cells. Using oriented titanium oxide (TiO{sub 2}) nanotube (NT) arrays has shown promise for dye-sensitized solar cells (DSSCs). High solar conversion efficiency requires that the incident light enters the cell from the photoelectrode side. However, for NT-based DSSCs, the light normally enters the cell through the counter electrode because a nontransparent titanium foil is typically used as the substrate for forming the aligned NTs and for making electrical contact with them. It has been synthetically challenging to prepare transparent TiO{sub 2} NT electrodes by directly anodizing Ti metal films on transparent conducting oxide (TCO) substrates because it is difficult to control the synthetic conditions. National Renewable Energy Laboratory (NREL) researchers have developed a general synthetic strategy for fabricating transparent TiO{sub 2} NT films on TCO substrates. With the aid of a conducting Nb-doped TiO{sub 2} (NTO) layer between the Ti film and TCO substrate, the Ti film can be anodized completely without degrading the TCO. The NTO layer protects the TCO from degradation through a self-terminating mechanism by arresting the electric field-assisted dissolution process at the NT-NTO interface. NREL researchers found that the illumination direction and wavelength of the light incident on the DSSCs strongly influenced the incident photon-to-current conversion efficiency, light-harvesting, and charge-collection properties, which, in turn, affect the photocurrent density, photovoltage, and solar energy conversion efficiency. Researchers also examined the effects of NT film thickness on the properties and performance of DSSCs and found that illuminating the cell from the photoelectrode side substantially increased the conversion efficiency compared with illuminating it from the counter-electrode side. This method solves a key challenge in fabricating

  1. Epidermal stem cells and skin tissue engineering in hairfollicle regeneration

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The reconstitution of a fully organized and functionalhair follicle from dissociated cells propagated underdefined tissue culture conditions is a challenge stillpending in tissue engineering. The loss of hair folliclescaused by injuries or pathologies such as alopecia notonly affects the patients' psychological well-being, butalso endangers certain inherent functions of the skin. Itis then of great interest to find different strategies aimingto regenerate or neogenerate the hair follicle underconditions proper of an adult individual. Based uponcurrent knowledge on the epithelial and dermal cells andtheir interactions during the embryonic hair generationand adult hair cycling, many researchers have tried toobtain mature hair follicles using different strategies andapproaches depending on the causes of hair loss. Thisreview summarizes current advances in the differentexperimental strategies to regenerate or neogenerate hairfollicles, with emphasis on those involving neogenesisof hair follicles in adult individuals using isolated cellsand tissue engineering. Most of these experiments wereperformed using rodent cells, particularly from embryonicor newborn origin. However, no successful strategy togenerate human hair follicles from adult cells has yetbeen reported. This review identifies several issues thatshould be considered to achieve this objective. Perhapsthe most important challenge is to provide threedimensionalculture conditionsmimicking the structure ofliving tissue. Improving culture conditions that allow theexpansion of specific cells while protecting their inductiveproperties, as well as methods for selecting populationsof epithelial stem cells, should give us the necessary toolsto overcome the difficulties that constrain human hairfollicle neogenesis. An analysis of patent trends showsthat the number of patent applications aimed at hairfollicle regeneration and neogenesis has been increasingduring the last decade. This field is attractive not only

  2. Recent developments in low cost silicon solar cells for terrestrial applications. [sheet production methods

    Science.gov (United States)

    Leipold, M. H.

    1978-01-01

    A variety of techniques may be used for photovoltaic energy systems. Concentrated or not concentrated sunlight may be employed, and a number of materials can be used, including silicon, gallium arsenide, cadmium sulfide, and cadmium telluride. Most of the experience, however, has been obtained with silicon cells employed without sunlight concentration. An industrial base exists at present for producing solar cells at a price in the range from $15 to $30 per peak watt. A major federal program has the objective to reduce the price of power provided by silicon solar systems to approximately $1 per peak watt in the early 1980's and $0.50 per watt by 1986. The approaches considered for achieving this objective are discussed.

  3. Quantum Dots Promise to Significantly Boost Solar Cell Efficiencies (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-08-01

    In the search for a third generation of solar-cell technologies, a leading candidate is the use of 'quantum dots' -- tiny spheres of semiconductor material measuring only about 2-10 billionths of a meter in diameter. Quantum dots have the potential to dramatically increase the efficiency of converting sunlight into energy -- perhaps even doubling it in some devices -- because of their ability to generate more than one bound electron-hole pair, or exciton, per incoming photon. NREL has produced quantum dots using colloidal suspensions; then, using molecular self-assembly, they have been fabricated into the first-ever quantum-dot solar cells. While these devices operate with only 4.4% efficiency, they demonstrate the capability for low-cost manufacturing.

  4. Dielectrophoresis-assisted massively parallel cell pairing and fusion based on field constriction created by a micro-orifice array sheet.

    Science.gov (United States)

    Kimura, Yuji; Gel, Murat; Techaumnat, Boonchai; Oana, Hidehiro; Kotera, Hidetoshi; Washizu, Masao

    2011-09-01

    In this paper, we present a novel electrofusion device that enables massive parallelism, using an electrically insulating sheet having a two-dimensional micro-orifice array. The sheet is sandwiched by a pair of micro-chambers with immersed electrodes, and each chamber is filled with the suspensions of the two types of cells to be fused. Dielectrophoresis, assisted by sedimentation, is used to position the cells in the upper chamber down onto the orifices, then the device is flipped over to position the cells on the other side, so that cell pairs making contact in the orifice are formed. When a pulse voltage is applied to the electrodes, most voltage drop occurs around the orifice and impressed on the cell membrane in the orifice. This makes possible the application of size-independent voltage to fuse two cells in contact at all orifices exclusively in 1:1 manner. In the experiment, cytoplasm of one of the cells is stained with a fluorescence dye, and the transfer of the fluorescence to the other cell is used as the indication of fusion events. The two-dimensional orifice arrangement at the pitch of 50 μm realizes simultaneous fusion of 6 × 10³ cells on a 4 mm diameter chip, and the fusion yield of 78-90% is achieved for various sizes and types of cells.

  5. Wrapping of a single bacterium with Functionalized - Chemically Modified Graphene (FCMG) sheets via highly specific protein-cell wall interaction

    Science.gov (United States)

    Mohanty, Nihar; Berry, Vikas

    2009-03-01

    Graphene has recently generated a lot of interest due to its unique structural and electrical properties. It's micro-scale area and sub-nano-scale thickness coupled with ballistic electronic transport at room temperature, low Johnston noise and low charge scattering, have made it a gold mine for novel applications. Since its discovery in 2004, there have been a plethora of studies on characterizing its unique physical, chemical and electrical properties of graphene as well as on integrating it with various physical/chemical systems to utilize these properties. But there have been limited or no studies on the integration of graphene with living microorganisms or mammalian cells. Here we describe the novel wrapping of a single live bacterium (Bacillus cereus) with a chemically modified graphene sheet functionalized with the protein Concanavalin-A (Con-A) via the highly specific Con-A - Teichoic acid interaction. We are investigating the structural and the electrical properties of these novel bacteria-FCMG ensembles. Further, we are also interested in characterizing this wrapping process in detail by studying the kinetics and the mechanism of action of bacterial-wrapping via 3D modelling. This is a first step towards the live-bio-nano-integration of graphene which would open up avenues for applications as diverse as bio-batteries using the Geobacter to recombinant enzyme compartmentalization.

  6. Speech recognition systems on the Cell Broadband Engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y; Jones, H; Vaidya, S; Perrone, M; Tydlitat, B; Nanda, A

    2007-04-20

    In this paper we describe our design, implementation, and first results of a prototype connected-phoneme-based speech recognition system on the Cell Broadband Engine{trademark} (Cell/B.E.). Automatic speech recognition decodes speech samples into plain text (other representations are possible) and must process samples at real-time rates. Fortunately, the computational tasks involved in this pipeline are highly data-parallel and can receive significant hardware acceleration from vector-streaming architectures such as the Cell/B.E. Identifying and exploiting these parallelism opportunities is challenging, but also critical to improving system performance. We observed, from our initial performance timings, that a single Cell/B.E. processor can recognize speech from thousands of simultaneous voice channels in real time--a channel density that is orders-of-magnitude greater than the capacity of existing software speech recognizers based on CPUs (central processing units). This result emphasizes the potential for Cell/B.E.-based speech recognition and will likely lead to the future development of production speech systems using Cell/B.E. clusters.

  7. Engineered cells as biosensing systems in biomedical analysis.

    Science.gov (United States)

    Raut, Nilesh; O'Connor, Gregory; Pasini, Patrizia; Daunert, Sylvia

    2012-04-01

    Over the past two decades there have been great advances in biotechnology, including use of nucleic acids, proteins, and whole cells to develop a variety of molecular analytical tools for diagnostic, screening, and pharmaceutical applications. Through manipulation of bacterial plasmids and genomes, bacterial whole-cell sensing systems have been engineered that can serve as novel methods for analyte detection and characterization, and as more efficient and cost-effective alternatives to traditional analytical techniques. Bacterial cell-based sensing systems are typically sensitive, specific and selective, rapid, easy to use, low-cost, and amenable to multiplexing, high-throughput, and miniaturization for incorporation into portable devices. This critical review is intended to provide an overview of available bacterial whole-cell sensing systems for assessment of a variety of clinically relevant analytes. Specifically, we examine whole-cell sensing systems for detection of bacterial quorum sensing molecules, organic and inorganic toxic compounds, and drugs, and for screening of antibacterial compounds for identification of their mechanisms of action. Methods used in the design and development of whole-cell sensing systems are also reviewed.

  8. The stem cell and tissue engineering research in Chinese ophthalmology

    Institute of Scientific and Technical Information of China (English)

    GE Jian; LIU Jingbo

    2007-01-01

    Much has been considerably developed recently in the ophthalmic research of stem cell (SC) and tissue engineering (TE).They have become closer to the clinical practice,standardized and observable.Leading edge research of SC and TE on the ocular surface reconstruction,neuroregeneration and protection,and natural animal model has become increasingly available.However,challenges remain on the way,especially on the aspects of function reconstruction and specific differentiation.This paper reviews the new developments in this area with an intention of identifying research priorities for the future.

  9. Adipose-derived stem cells and periodontal tissue engineering.

    Science.gov (United States)

    Tobita, Morikuni; Mizuno, Hiroshi

    2013-01-01

    Innovative developments in the multidisciplinary field of tissue engineering have yielded various implementation strategies and the possibility of functional tissue regeneration. Technologic advances in the combination of stem cells, biomaterials, and growth factors have created unique opportunities to fabricate tissues in vivo and in vitro. The therapeutic potential of human multipotent mesenchymal stem cells (MSCs), which are harvested from bone marrow and adipose tissue, has generated increasing interest in a wide variety of biomedical disciplines. These cells can differentiate into a variety of tissue types, including bone, cartilage, fat, and nerve tissue. Adipose-derived stem cells have some advantages compared with other sources of stem cells, most notably that a large number of cells can be easily and quickly isolated from adipose tissue. In current clinical therapy for periodontal tissue regeneration, several methods have been developed and applied either alone or in combination, such as enamel matrix proteins, guided tissue regeneration, autologous/allogeneic/xenogeneic bone grafts, and growth factors. However, there are various limitations and shortcomings for periodontal tissue regeneration using current methods. Recently, periodontal tissue regeneration using MSCs has been examined in some animal models. This method has potential in the regeneration of functional periodontal tissues because the various secreted growth factors from MSCs might not only promote the regeneration of periodontal tissue but also encourage neovascularization of the damaged tissues. Adipose-derived stem cells are especially effective for neovascularization compared with other MSC sources. In this review, the possibility and potential of adipose-derived stem cells for regenerative medicine are introduced. Of particular interest, periodontal tissue regeneration with adipose-derived stem cells is discussed.

  10. Semaphorin 3A-modified adipose-derived stem cell sheet may improve osseointegration in a type 2 diabetes mellitus rat model

    Science.gov (United States)

    Fang, Kaixiu; Song, Wen; Wang, Lifeng; Xu, Xiaoru; Tan, Naiwen; Zhang, Sijia; Wei, Hongbo; Song, Yingliang

    2016-01-01

    Although titanium (Ti) implants are considered to be an optimal choice for the replacement of missing teeth, it remains difficult to obtain sufficient osseointegration in patients with type 2 diabetes mellitus (T2DM). The present study aimed to investigate whether adipose-derived stem cells (ASCs) may be used to improve Ti implant osseointegration in T2DM conditions with the addition of semaphorin 3A (Sema3A), a recently identified osteoprotective protein. Cell morphology was observed using a scanning electron microscope. Cell proliferation was determined using Cell Counting Kit-8. Osteogenic differentiation was confirmed by the staining of alkaline phosphatase, collagen secretion and calcium deposition. An in vivo evaluation was performed in the T2DM rat model, which was induced by a high-fat diet and a low-dose streptozotocin intraperitoneal injection. A Sema3A-modified ASC sheet was wrapped around the Ti implant, which was subsequently inserted into the tibia. The rats were then exposed to Sema3A stimulation. The morphology and proliferation ability of ASCs remained unchanged; however, their osteogenic differentiation ability was increased. Micro-computed tomography scanning and histological observations confirmed that formation of new bone was improved with the use of the Sema3A-modified ASCs sheet. The present study indicated that the Sema3A-modified ASCs sheet may be used to improve osseointegration under T2DM conditions. PMID:27484405

  11. Reverse engineering human neurodegenerative disease using pluripotent stem cell technology.

    Science.gov (United States)

    Liu, Ying; Deng, Wenbin

    2016-05-01

    With the technology of reprogramming somatic cells by introducing defined transcription factors that enables the generation of "induced pluripotent stem cells (iPSCs)" with pluripotency comparable to that of embryonic stem cells (ESCs), it has become possible to use this technology to produce various cells and tissues that have been difficult to obtain from living bodies. This advancement is bringing forth rapid progress in iPSC-based disease modeling, drug screening, and regenerative medicine. More and more studies have demonstrated that phenotypes of adult-onset neurodegenerative disorders could be rather faithfully recapitulated in iPSC-derived neural cell cultures. Moreover, despite the adult-onset nature of the diseases, pathogenic phenotypes and cellular abnormalities often exist in early developmental stages, providing new "windows of opportunity" for understanding mechanisms underlying neurodegenerative disorders and for discovering new medicines. The cell reprogramming technology enables a reverse engineering approach for modeling the cellular degenerative phenotypes of a wide range of human disorders. An excellent example is the study of the human neurodegenerative disease amyotrophic lateral sclerosis (ALS) using iPSCs. ALS is a progressive neurodegenerative disease characterized by the loss of upper and lower motor neurons (MNs), culminating in muscle wasting and death from respiratory failure. The iPSC approach provides innovative cell culture platforms to serve as ALS patient-derived model systems. Researchers have converted iPSCs derived from ALS patients into MNs and various types of glial cells, all of which are involved in ALS, to study the disease. The iPSC technology could be used to determine the role of specific genetic factors to track down what's wrong in the neurodegenerative disease process in the "disease-in-a-dish" model. Meanwhile, parallel experiments of targeting the same specific genes in human ESCs could also be performed to control

  12. Metabolically Engineered Fungal Cells With Increased Content Of Polyunsaturated Fatty Acids

    DEFF Research Database (Denmark)

    2008-01-01

    This invention relates to the production of fatty acids and particularly to the production of the polyunsaturated fatty acids (PUFAs) arachidonic acid (ARA) and eicosapentaenoic acid (EPA) in genetically engineered fungal cells, in particular, to metabolically engineered Saccharomyces cerevisiae...

  13. Adult stem cells applied to tissue engineering and regenerative medicine.

    Science.gov (United States)

    Cuenca-López, M D; Zamora-Navas, P; García-Herrera, J M; Godino, M; López-Puertas, J M; Guerado, E; Becerra, J; Andrades, J A

    2008-01-01

    Regeneration takes place in the body at a moment or another throughout life. Bone, cartilage, and tendons (the key components of the structure and articulation in the body) have a limited capacity for self-repair and, after traumatic injury or disease, the regenerative power of adult tissue is often insufficient. When organs or tissues are irreparably damaged, they may be replaced by an artificial device or by a donor organ. However, the number of available donor organs is considerably limited. Generation of tissue-engineered replacement organs by extracting stem cells from the patient, growing them and modifying them in clinical conditions after re-introduction in the body represents an ideal source for corrective treatment. Mesenchymal stem cells (MSCs) are the multipotential progenitors that give rise to skeletal cells, vascular smooth muscle cells, muscle (skeletal and cardiac muscle), adipocytes (fat tissue) and hematopoietic (blood)-supportive stromal cells. MSCs are found in multiple connective tissues, in adult bone marrow, skeletal muscles and fat pads. The wide representation in adult tissues may be related to the existence of a circulating blood pool or that MSCs are associated to the vascular system.

  14. Human dental pulp stem cell is a promising autologous seed cell for bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    LI Jing-hui; LIU Da-yong; ZHANG Fang-ming; WANG Fan; ZHANG Wen-kui; ZHANG Zhen-ting

    2011-01-01

    Background The seed cell is a core problem in bone tissue engineering research.Recent research indicates that human dental pulp stem cells (hDPSCs) can differentiate into osteoblasts in vitro,which suggests that they may become a new kind of seed cells for bone tissue engineering.The aim of this study was to evaluate the osteogenic differentiation of hDPSCs in vitro and bone-like tissue formation when transplanted with three-dimensional gelatin scaffolds in vivo,and hDPSCs may become appropriate seed cells for bone tissue engineering.Methods We have utilized enzymatic digestion to obtain hDPSCs from dental pulp tissue extracted during orthodontic treatment.After culturing and expansion to three passages,the cells were seeded in 6-well plates or on three-dimensional gelatin scaffolds and cultured in osteogenic medium.After 14 days in culture,the three-dimensional gelatin scaffolds were implanted subcutaneously in nude mice for 4 weeks.In 6-well plate culture,osteogenesis was assessed by alkaline phosphatase staining,Von Kossa staining,and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the osteogenesis-specific genes type I collagen (COL l),bone sialoprotein (BSP),osteocalcin (OCN),RUNX2,and osterix (OSX).In three-dimensional gelatin scaffold culture,X-rays,hematoxylin/eosin staining,and immunohistochemical staining were used to examine bone formation.Results In vitro studies revealed that hDPSCs do possess osteogenic differentiation potential.In vivo studies revealed that hDPSCs seeded on gelatin scaffolds can form bone structures in heterotopic sites of nude mice.Conclusions These findings suggested that hDPSCs may be valuable as seed cells for bone tissue engineering.As a special stem cell source,hDPSCs may blaze a new path for bone tissue engineering.

  15. Dependence of lattice strain relaxation, absorbance, and sheet resistance on thickness in textured ZnO@B transparent conductive oxide for thin-film solar cell applications

    OpenAIRE

    2016-01-01

    The interplay of surface texture, strain relaxation, absorbance, grain size, and sheet resistance in textured, boron-doped ZnO (ZnO@B), transparent conductive oxide (TCO) materials of different thicknesses used for thin film, solar cell applications is investigated. The residual strain induced by the lattice mismatch and the difference in the thermal expansion coefficient for thicker ZnO@B is relaxed, leading to an increased surface texture, stronger absorbance, larger grain size, and lower s...

  16. Reconstitution of the complete rupture in musculotendinous junction using skeletal muscle-derived multipotent stem cell sheet-pellets as a “bio-bond”

    Directory of Open Access Journals (Sweden)

    Hiroyuki Hashimoto

    2016-07-01

    Full Text Available Background. Significant and/or complete rupture in the musculotendinous junction (MTJ is a challenging lesion to treat because of the lack of reliable suture methods. Skeletal muscle-derived multipotent stem cell (Sk-MSC sheet-pellets, which are able to reconstitute peripheral nerve and muscular/vascular tissues with robust connective tissue networks, have been applied as a “bio-bond”. Methods. Sk-MSC sheet-pellets, derived from GFP transgenic-mice after 7 days of expansion culture, were detached with EDTA to maintain cell–cell connections. A completely ruptured MTJ model was prepared in the right tibialis anterior (TA of the recipient mice, and was covered with sheet-pellets. The left side was preserved as a contralateral control. The control group received the same amount of the cell-free medium. The sheet-pellet transplantation (SP group was further divided into two groups; as the short term (4–8 weeks and long term (14–18 weeks recovery group. At each time point after transplantation, tetanic tension output was measured through the electrical stimulation of the sciatic nerve. The behavior of engrafted GFP+ tissues and cells was analyzed by fluorescence immunohistochemistry. Results. The SP short term recovery group showed average 64% recovery of muscle mass, and 36% recovery of tetanic tension output relative to the contralateral side. Then, the SP long term recovery group showed increased recovery of average muscle mass (77% and tetanic tension output (49%. However, the control group showed no recovery of continuity between muscle and tendon, and demonstrated increased muscle atrophy, with coalescence to the tibia during 4–8 weeks after operation. Histological evidence also supported the above functional recovery of SP group. Engrafted Sk-MSCs primarily formed the connective tissues and muscle fibers, including nerve-vascular networks, and bridged the ruptured tendon–muscle fiber units, with differentiation into skeletal

  17. Multifunctional Fullerene Derivative for Interface Engineering in Perovskite Solar Cells.

    Science.gov (United States)

    Li, Yaowen; Zhao, Yue; Chen, Qi; Yang, Yang Michael; Liu, Yongsheng; Hong, Ziruo; Liu, Zonghao; Hsieh, Yao-Tsung; Meng, Lei; Li, Yongfang; Yang, Yang

    2015-12-16

    In perovskite based planar heterojunction solar cells, the interface between the TiO2 compact layer and the perovskite film is critical for high photovoltaic performance. The deep trap states on the TiO2 surface induce several challenging issues, such as charge recombination loss and poor stability etc. To solve the problems, we synthesized a triblock fullerene derivative (PCBB-2CN-2C8) via rational molecular design for interface engineering in the perovskite solar cells. Modifying the TiO2 surface with the compound significantly improves charge extraction from the perovskite layer. Together with its uplifted surface work function, open circuit voltage and fill factor are dramatically increased from 0.99 to 1.06 V, and from 72.2% to 79.1%, respectively, resulting in 20.7% improvement in power conversion efficiency for the best performing devices. Scrutinizing the electrical properties of this modified interfacial layer strongly suggests that PCBB-2CN-2C8 passivates the TiO2 surface and thus reduces charge recombination loss caused by the deep trap states of TiO2. The passivation effect is further proven by stability testing of the perovskite solar cells with shelf lifetime under ambient conditions improved by a factor of more than 4, from ∼40 h to ∼200 h, using PCBB-2CN-2C8 as the TiO2 modification layer. This work offers not only a promising material for cathode interface engineering, but also provides a viable approach to address the challenges of deep trap states on TiO2 surface in planar perovskite solar cells.

  18. Advancing Concentrating Solar Power Research (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) provide scientific, engineering, and analytical expertise to help advance innovation in concentrating solar power (CSP). This fact sheet summarizes how NREL is advancing CSP research.

  19. Engineering tumor cell targeting in nanoscale amyloidal materials

    Science.gov (United States)

    Unzueta, Ugutz; Seras-Franzoso, Joaquin; Virtudes Céspedes, María; Saccardo, Paolo; Cortés, Francisco; Rueda, Fabián; Garcia-Fruitós, Elena; Ferrer-Miralles, Neus; Mangues, Ramon; Vázquez, Esther; Villaverde, Antonio

    2017-01-01

    Bacterial inclusion bodies are non-toxic, mechanically stable and functional protein amyloids within the nanoscale size range that are able to naturally penetrate into mammalian cells, where they deliver the embedded protein in a functional form. The potential use of inclusion bodies in protein delivery or protein replacement therapies is strongly impaired by the absence of specificity in cell binding and penetration, thus preventing targeting. To address this issue, we have here explored whether the genetic fusion of two tumor-homing peptides, the CXCR4 ligands R9 and T22, to an inclusion body-forming green fluorescent protein (GFP), would keep the interaction potential and the functionality of the fused peptides and then confer CXCR4 specificity in cell binding and further uptake of the materials. The fusion proteins have been well produced in Escherichia coli in their full-length form, keeping the potential for fluorescence emission of the partner GFP. By using specific inhibitors of CXCR4 binding, we have demonstrated that the engineered protein particles are able to penetrate CXCR4+ cells, in a receptor-mediated way, without toxicity or visible cytopathic effects, proving the availability of the peptide ligands on the surface of inclusion bodies. Since no further modification is required upon their purification, the biological production of genetically targeted inclusion bodies opens a plethora of cost-effective possibilities in the tissue-specific intracellular transfer of functional proteins through the use of structurally and functionally tailored soft materials.

  20. Tissue engineering bone using autologous progenitor cells in the peritoneum.

    Directory of Open Access Journals (Sweden)

    Jinhui Shen

    Full Text Available Despite intensive research efforts, there remains a need for novel methods to improve the ossification of scaffolds for bone tissue engineering. Based on a common phenomenon and known pathological conditions of peritoneal membrane ossification following peritoneal dialysis, we have explored the possibility of regenerating ossified tissue in the peritoneum. Interestingly, in addition to inflammatory cells, we discovered a large number of multipotent mesenchymal stem cells (MSCs in the peritoneal lavage fluid from mice with peritoneal catheter implants. The osteogenic potential of these peritoneal progenitor cells was demonstrated by their ability to easily infiltrate decalcified bone implants, produce osteocalcin and form mineralized bone in 8 weeks. Additionally, when poly(l-lactic acid scaffolds loaded with bone morphogenetic protein-2 (a known osteogenic differentiation agent were implanted into the peritoneum, signs of osteogenesis were seen within 8 weeks of implantation. The results of this investigation support the concept that scaffolds containing BMP-2 can stimulate the formation of bone in the peritoneum via directed autologous stem and progenitor cell responses.

  1. Engineering microbial fuels cells: recent patents and new directions.

    Science.gov (United States)

    Biffinger, Justin C; Ringeisen, Bradley R

    2008-01-01

    Fundamental research into how microbes generate electricity within microbial fuel cells (MFCs) has far outweighed the practical application and large scale development of microbial energy harvesting devices. MFCs are considered alternatives to standard commercial polymer electrolyte membrane (PEM) fuel cell technology because the fuel supply does not need to be purified, ambient operating temperatures are maintained with biologically compatible materials, and the biological catalyst is self-regenerating. The generation of electricity during wastewater treatment using MFCs may profoundly affect the approach to anaerobic treatment technologies used in wastewater treatment as a result of developing this energy harvesting technology. However, the materials and engineering designs for MFCs were identical to commercial fuel cells until 2003. Compared to commercial fuel cells, MFCs will remain underdeveloped as long as low power densities are generated from the best systems. The variety of designs for MFCs has expanded rapidly in the last five years in the literature, but the patent protection has lagged behind. This review will cover recent and important patents relating to MFC designs and progress.

  2. Engineering antigen-specific T cells from genetically modified human hematopoietic stem cells in immunodeficient mice.

    Directory of Open Access Journals (Sweden)

    Scott G Kitchen

    Full Text Available There is a desperate need for effective therapies to fight chronic viral infections. The immune response is normally fastidious at controlling the majority of viral infections and a therapeutic strategy aimed at reestablishing immune control represents a potentially powerful approach towards treating persistent viral infections. We examined the potential of genetically programming human hematopoietic stem cells to generate mature CD8+ cytotoxic T lymphocytes that express a molecularly cloned, "transgenic" human anti-HIV T cell receptor (TCR. Anti-HIV TCR transduction of human hematopoietic stem cells directed the maturation of a large population of polyfunctional, HIV-specific CD8+ cells capable of recognizing and killing viral antigen-presenting cells. Thus, through this proof-of-concept we propose that genetic engineering of human hematopoietic stem cells will allow the tailoring of effector T cell responses to fight HIV infection or other diseases that are characterized by the loss of immune control.

  3. Production and characterization of engineered alginate-based microparticles containing ECM powder for cell/tissue engineering applications.

    Science.gov (United States)

    Mazzitelli, Stefania; Luca, Giovanni; Mancuso, Francesca; Calvitti, Mario; Calafiore, Riccardo; Nastruzzi, Claudio; Johnson, Scott; Badylak, Stephen F

    2011-03-01

    A method for the production of engineered alginate-based microparticles, containing extracellular matrix and neonatal porcine Sertoli cells (SCs), is described. As a source for extracellular matrix, a powder form of isolated and purified urinary bladder matrix (UBM) was employed. We demonstrated that the incorporation of UBM does not significantly alter the morphological and dimensional characteristics of the microparticles. The alginate microparticles were used for SC encapsulation as an immunoprotective barrier for transplant purposes, while the co-entrapped UBM promoted retention of cell viability and function. These engineered microparticles could represent a novel approach to enhancing immunological acceptance and increasing the functional life-span of the entrapped cells for cell/tissue engineering applications. In this respect, it is noteworthy that isolated neonatal porcine SCs, administered alone in highly biocompatible microparticles, led to diabetes prevention and reversion in nonobese diabetic (NOD) mice.

  4. 拉森钢板桩支护在河道堤防抢险工程中的应用%The Application of Larsen Steel Sheet Pile Support in the Rescue and Engineering River Embankments

    Institute of Scientific and Technical Information of China (English)

    罗永青

    2014-01-01

    This article introduces the emergency rescue and repair by using the steel sheet pile supportand cofferdam construction schemes in the white mud colapsed engineering of Leizhou youth canal river of Zhanjiang city Guangdong province, which has achieved the effect of fast, safety and saving the cost of construction project, to provide reference for similar rescue and engineering construction.%本文介绍了广东湛江市雷州青年运河东海河白泥沟堤段坍塌抢险工程中使用钢板桩支护、围堰的施工方案进行抢险并修复,取得快速、安全、节省工程成本等效果,供同类抢险工程施工提供参考。

  5. Genetic engineering of platelets to neutralize circulating tumor cells.

    Science.gov (United States)

    Li, Jiahe; Sharkey, Charles C; Wun, Brittany; Liesveld, Jane L; King, Michael R

    2016-04-28

    Mounting experimental evidence demonstrates that platelets support cancer metastasis. Within the circulatory system, platelets guard circulating tumor cells (CTCs) from immune elimination and promote their arrest at the endothelium, supporting CTC extravasation into secondary sites. Neutralization of CTCs in blood circulation can potentially attenuate metastases to distant organs. Therefore, extensive studies have explored the blockade of platelet-CTC interactions as an anti-metastatic strategy. Such an intervention approach, however, may cause bleeding disorders since the platelet-CTC interactions inherently rely on the blood coagulation cascade including platelet activation. On the other hand, platelets have been genetically engineered to correct inherited bleeding disorders in both animal models and human clinical trials. In this study, inspired by the physical association between platelets and CTCs, platelets were genetically modified to express surface-bound tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a cytokine known to induce apoptosis specifically in tumor cells. The TRAIL-expressing platelets were demonstrated to kill cancer cells in vitro and significantly reduce metastases in a mouse model of prostate cancer metastasis. Our results suggest that using platelets to produce and deliver cancer-specific therapeutics can provide a Trojan-horse strategy of neutralizing CTCs to attenuate metastasis.

  6. Re: Engineered Nanoparticles Induce Cell Apoptosis: Potential for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Fehmi Narter

    2016-09-01

    Full Text Available Engineered nanoparticles (ENPs have been widely applied in industry, biology and medicine recently (i.e. clothes, sunscreens, cosmetics, foods, diagnostic medicine, imaging and drug delivery. There are many kinds of manufactured nanomaterial products including TiO2, ZnO, CeO2, Fe2O3, and CuO (as metal oxide nanoparticles as well as gold, silver, platinum and palladium (as metal nanoparticles, and other carbon-based ENP’s such as carbon nanotububes and quantum dots. ENPs with their sizes no larger than 100 nm are able to enter the human body and accumulate in organs and cause toxic effects. In many researches, ENP effects on the cancer cells of different organs with related cell apoptosis were noted (AgNP, nano-Cr2O3, Au-Fe2O3 NPs, nano-TiO2, nano-HAP, nano-Se, MoO3 nanoplate, Realgar nanoparticles. ENPs, with their unique properties, such as surface charge, particle size, composition and surface modification with tissue recognition ligands or antibodies, has been increasingly explored as a tool to carry small molecular weight drugs as well as macromolecules for cancer therapy, thus generating the new concept “nanocarrier”. Direct induction of cell apoptosis by ENPs provides an opportunity for cancer treatment. In the century of nanomedicine that depends on development of the nanotechnology, ENPs have a great potential for application in cancer treatment with minimal side effects.

  7. Process engineering of ceramic composite coatings for fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.; Kim, H.; Chen, M.; Yang, Q.; Troczynski, T. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Metals and Materials Engineering

    2003-07-01

    Researchers at UBCeram at the Department of Metals and Materials Engineering at the University of British Columbia have developed a technology to chemically bond composite sol-gel (CB-CSG) coating onto metallic surfaces of complex or concave shapes. The process has been optimized for electrically resistive coatings and corrosion-resistant coatings. The CSG is sprayed onto metallic surfaces and is heat-treated at 300 degrees C to partially dehydrate the hydroxides. The CSG film is then chemically bonded through reaction of active alumina with metal phosphates, such as aluminium phosphate. A new chromate-free process is being developed to address the issue of coatings porosity. The electrodeposition technique involves polymer particles mixed with suspended fine alumina particles which are co-deposited by electrophoretic means or by electrocoagulation. The composite e-coatings have excellent mechanical properties and are being considered as a protective coating for various components of fuel cell systems. 9 refs., 7 figs.

  8. CRISPR mediated somatic cell genome engineering in the chicken.

    Science.gov (United States)

    Véron, Nadège; Qu, Zhengdong; Kipen, Phoebe A S; Hirst, Claire E; Marcelle, Christophe

    2015-11-01

    Gene-targeted knockout technologies are invaluable tools for understanding the functions of genes in vivo. CRISPR/Cas9 system of RNA-guided genome editing is revolutionizing genetics research in a wide spectrum of organisms. Here, we combined CRISPR with in vivo electroporation in the chicken embryo to efficiently target the transcription factor PAX7 in tissues of the developing embryo. This approach generated mosaic genetic mutations within a wild-type cellular background. This series of proof-of-principle experiments indicate that in vivo CRISPR-mediated cell genome engineering is an effective method to achieve gene loss-of-function in the tissues of the chicken embryo and it completes the growing genetic toolbox to study the molecular mechanisms regulating development in this important animal model.

  9. Stem Cells for Bone Regeneration: From Cell-Based Therapies to Decellularised Engineered Extracellular Matrices

    Science.gov (United States)

    Fisher, James N.; Peretti, Giuseppe M.; Scotti, Celeste

    2016-01-01

    Currently, autologous bone grafting represents the clinical gold standard in orthopaedic surgery. In certain cases, however, alternative techniques are required. The clinical utility of stem and stromal cells has been demonstrated for the repair and regeneration of craniomaxillofacial and long bone defects although clinical adoption of bone tissue engineering protocols has been very limited. Initial tissue engineering studies focused on the bone marrow as a source of cells for bone regeneration, and while a number of promising results continue to emerge, limitations to this technique have prompted the exploration of alternative cell sources, including adipose and muscle tissue. In this review paper we discuss the advantages and disadvantages of cell sources with a focus on adipose tissue and the bone marrow. Additionally, we highlight the relatively recent paradigm of developmental engineering, which promotes the recapitulation of naturally occurring developmental processes to allow the implant to optimally respond to endogenous cues. Finally we examine efforts to apply lessons from studies into different cell sources and developmental approaches to stimulate bone growth by use of decellularised hypertrophic cartilage templates. PMID:26997959

  10. Tissue-culture light sheet fluorescence microscopy (TC-LSFM) allows long-term imaging of three-dimensional cell cultures under controlled conditions.

    Science.gov (United States)

    Pampaloni, Francesco; Berge, Ulrich; Marmaras, Anastasios; Horvath, Peter; Kroschewski, Ruth; Stelzer, Ernst H K

    2014-10-01

    Fluorescence long-term imaging of cellular processes in three-dimensional cultures requires the control of media supply, temperature, and pH, as well as minimal photodamage. We describe a system based on a light sheet fluorescence microscope (LSFM), which is optimized for long-term, multi-position imaging of three-dimensional in-gel cell cultures. The system integrates a stable culture condition control system in the optical path of the light-sheet microscope. A further essential element is a biocompatible agarose container suitable for the LSFM, in which any cell type can be cultured in different gel matrices. The TC-LSFM allows studying any in vitro cultured cell type reacting to, dividing in, or migrating through a three-dimensional extracellular matrix (ECM) gel. For this reason we called it "tissue culture-LSFM" (TC-LSFM). The TC-LSFM system allows fast imaging at multiple locations within a millimeter-sized ECM gel. This increases the number of analyzed events and allows testing population effects. As an example, we show the maturation of a cyst of MDCK (canine kidney epithelial) cells over a period of three days. Moreover, we imaged, tracked, and analyzed MDCK cells during the first five days of cell aggregate formation and discovered a remarkable heterogeneity in cell cycle lengths and an interesting cell death pattern. Thus, TC-LSFM allows performing new long-term assays assessing cellular behavior in three-dimensional ECM-gel cultures. For example migration, invasion or differentiation in epithelial cell systems, stem cells, as well as cancer cells can be investigated.

  11. A blueprint for engineering cell fate: current technologies to reprogram cell identity

    Institute of Scientific and Technical Information of China (English)

    Samantha A Morris; George Q Daley

    2013-01-01

    Human diseases such as heart failure,diabetes,neurodegenerative disorders,and many others result from the deficiency or dysfunction of critical cell types.Strategies for therapeutic tissue repair or regeneration require the in vitro manufacture of clinically relevant quantities of defined cell types.In addition to transplantation therapy,the generation of otherwise inaccessible cells also permits disease modeling,toxicology testing and drug discovery in vitro.In this review,we discuss current strategies to manipulate the identity of abundant and accessible cells by differentiation from an induced pluripotent state or direct conversion between differentiated states.We contrast these approaches with recent advances employing partial reprogramming to facilitate lineage switching,and discuss the mechanisms underlying the engineering of cell fate.Finally,we address the current limitations of the field and how the resulting cell types can be assessed to ensure the production of medically relevant populations.

  12. AI applications in sheet metal forming

    CERN Document Server

    Hussein, Hussein

    2017-01-01

    This book comprises chapters on research work done around the globe in the area of artificial intelligence (AI) applications in sheet metal forming. The first chapter offers an introduction to various AI techniques and sheet metal forming, while subsequent chapters describe traditional procedures/methods used in various sheet metal forming processes, and focus on the automation of those processes by means of AI techniques, such as KBS, ANN, GA, CBR, etc. Feature recognition and the manufacturability assessment of sheet metal parts, process planning, strip-layout design, selecting the type and size of die components, die modeling, and predicting die life are some of the most important aspects of sheet metal work. Traditionally, these activities are highly experience-based, tedious and time consuming. In response, researchers in several countries have applied various AI techniques to automate these activities, which are covered in this book. This book will be useful for engineers working in sheet metal industri...

  13. Engineering complex tissue-like microgel arrays for evaluating stem cell differentiation

    DEFF Research Database (Denmark)

    Guermani, Enrico; Shaki, Hossein; Mohanty, Soumyaranjan

    2016-01-01

    Development of tissue engineering scaffolds with native-like biology and microarchitectures is a prerequisite for stem cell mediated generation of off-the-shelf-tissues. So far, the field of tissue engineering has not full-filled its grand potential of engineering such combinatorial scaffolds...... for engineering functional tissues. This is primarily due to the many challenges associated with finding the right microarchitectures and ECM compositions for optimal tissue regeneration. Here, we have developed a new microgel array to address this grand challenge through robotic printing of complex stem cell...... platform will be used for high-throughput identification of combinatorial and native-like scaffolds for tissue engineering of functional organs....

  14. Effects of Hemodynamic Forces on the Vascular Differentiation of Stem Cells: Implications for Vascular Graft Engineering

    Science.gov (United States)

    Diop, Rokhaya; Li, Song

    Although the field of vascular tissue engineering has made tremendous advances in the past decade, several complications have yet to be overcome in order to produce biocompatible small-diameter vascular conduits with long-term patency. Stem cells and progenitor cells represent potential cell sources in the development of autologous (or allogeneic), nonthrombogenic vascular grafts with mechanical properties comparable to native blood vessel. However, a better understanding of the effects of mechanical forces on stem cells and progenitor cells is needed to properly utilize these cells for tissue engineering applications. In this chapter, we discuss the current understanding of the effects of hemodynamic forces on the differentiation and function of adult stem cells, embryonic stem cells, and progenitor cells. We also review the use of stem cells and progenitor cells in vascular graft engineering.

  15. Cell engineering: nanometric grafting of poly-N-isopropylacrylamide onto polystyrene film by different doses of gamma radiation

    Directory of Open Access Journals (Sweden)

    Esmaeil Biazar

    2010-07-01

    the grafted surfaces. Differential scanning calorimetry analysis also revealed the low critical solution temperature of the grafted sample to be 32°C. Thermoresponsive polymers were grafted to dishes covalently which allowed fibroblast cells to attach and proliferate at 37°C; the cells also detached spontaneously without using enzymes when the temperature dropped below 32°C. This characteristic proves that this type of grafted material has potential as a biomaterial for cell sheet engineering.Keywords: Nanometric grafting, PNIPAAm, polystyrene film, gamma ray, dose, cell engineering

  16. Engineered antifouling microtopographies: surface pattern effects on cell distribution.

    Science.gov (United States)

    Decker, Joseph T; Sheats, Julian T; Brennan, Anthony B

    2014-12-23

    Microtopography has been observed to lead to altered attachment behavior for marine fouling organisms; however, quantification of this phenomenon is lacking in the scientific literature. Here, we present quantitative measurement of the disruption of normal attachment behavior of the fouling algae Ulva linza by antifouling microtopographies. The distribution of the diatom Navicula incerta was shown to be unaffected by the presence of topography. The radial distribution function was calculated for both individual zoospores and cells as well as aggregates of zoospores from attachment data for a variety topographic configurations and at a number of different attachment densities. Additionally, the screening distance and maximum values were mapped according to the location of zoospore aggregates within a single unit cell. We found that engineered topographies decreased the distance between spore aggregates compared to that for a smooth control surface; however, the distributions for individual spores were unchanged. We also found that the local attachment site geometry affected the screening distance for aggregates of zoospores, with certain geometries decreasing screening distance and others having no measurable effect. The distribution mapping techniques developed and explored in this article have yielded important insight into the design parameters for antifouling microtopographies that can be implemented in the next generation of antifouling surfaces.

  17. Evaluation of silk biomaterials in combination with extracellular matrix coatings for bladder tissue engineering with primary and pluripotent cells.

    Directory of Open Access Journals (Sweden)

    Debra Franck

    Full Text Available Silk-based biomaterials in combination with extracellular matrix (ECM coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1 or rough, porous lamellar-like sheets (Group 2. Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC and induced pluripotent stem (iPS cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of α-actin and SM22α mRNA and protein expression levels following TGFβ1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These

  18. Differentiation of human ESCs to retinal ganglion cells using a CRISPR engineered reporter cell line.

    Science.gov (United States)

    Sluch, Valentin M; Davis, Chung-ha O; Ranganathan, Vinod; Kerr, Justin M; Krick, Kellin; Martin, Russ; Berlinicke, Cynthia A; Marsh-Armstrong, Nicholas; Diamond, Jeffrey S; Mao, Hai-Quan; Zack, Donald J

    2015-11-13

    Retinal ganglion cell (RGC) injury and cell death from glaucoma and other forms of optic nerve disease is a major cause of irreversible vision loss and blindness. Human pluripotent stem cell (hPSC)-derived RGCs could provide a source of cells for the development of novel therapeutic molecules as well as for potential cell-based therapies. In addition, such cells could provide insights into human RGC development, gene regulation, and neuronal biology. Here, we report a simple, adherent cell culture protocol for differentiation of hPSCs to RGCs using a CRISPR-engineered RGC fluorescent reporter stem cell line. Fluorescence-activated cell sorting of the differentiated cultures yields a highly purified population of cells that express a range of RGC-enriched markers and exhibit morphological and physiological properties typical of RGCs. Additionally, we demonstrate that aligned nanofiber matrices can be used to guide the axonal outgrowth of hPSC-derived RGCs for in vitro optic nerve-like modeling. Lastly, using this protocol we identified forskolin as a potent promoter of RGC differentiation.

  19. Discarded leukoreduction filters: a new source of stem cells for research, cell engineering and therapy?

    Science.gov (United States)

    Peytour, Yann; Villacreces, Arnaud; Chevaleyre, Jean; Ivanovic, Zoran; Praloran, Vincent

    2013-09-01

    New adult stem cell sources, devoid of the technical/ethical/economical barriers of those presently available, would favor the ongoing development of in vitro cell engineering and transplantation. Hematopoietic transplantation opened the way to and remains the most successful cell transplantation procedure. CD34+ cells that include hematopoietic stem cells (HSCs) and hematopoietic progenitors (HPs) are presently harvested from bone marrow (BM), cord blood or peripheral blood (after being mobilized from BM). The panel of potential donors, the quantities of collected cells and some other technical/medical problems still represent limiting factors to their transplantation in some patients. Steady state peripheral blood (SSPB) contains very low frequencies of CD34+ cells. They are trapped in leukoreduction filters (LRFs), which are discarded after the preparation of therapeutic red blood cell concentrates from individual blood donations. We recently developed a procedure allowing the easy and rapid elution of CD34+ cells from LRFs and we showed that they are functionally similar to those harvested from other sources. After providing an overview of the sources, interests and limitations of therapeutic HSCs presently available, we will provide arguments based on our and others' results suggesting that SSPB could become an attractive source of HSCs for hematopoietic transplantation and of other cell types for various research/development procedures.

  20. Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Arend Jan Schouten

    2011-10-01

    Full Text Available Polycaprolactone (PCL polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suitable in applications in which scaffold support is needed for a shorter time. A recently developed class of polyacylurethanes (PAUs is expected to fulfill such requirements. Our aim was to assess in vitro the degradation of PAUs and evaluate their suitability as temporary scaffold materials to support soft tissue repair. With both a mass loss of 2.5–3.0% and a decrease in molar mass of approx. 35% over a period of 80 days, PAUs were shown to degrade via both bulk and surface erosion mechanisms. Fourier Transform Infra Red (FTIR spectroscopy was successfully applied to study the extent of PAUs microphase separation during in vitro degradation. The microphase separated morphology of PAU1000 (molar mass of the oligocaprolactone soft segment = 1000 g/mol provided this polymer with mechano-physical characteristics that would render it a suitable material for constructs and devices. PAU1000 exhibited excellent haemocompatibility in vitro. In addition, PAU1000 supported both adhesion and proliferation of vascular endothelial cells and this could be further enhanced by pre-coating of PAU1000 with fibronectin (Fn. The contact angle of PAU1000 decreased both with in vitro degradation and by incubation in biological fluids. In endothelial cell culture medium the contact angle reached 60°, which is optimal for cell adhesion. Taken together, these results support the application of PAU1000 in the field of soft tissue repair as a temporary degradable scaffold.

  1. Engineering cell-compatible paper chips for cell culturing, drug screening, and mass spectrometric sensing.

    Science.gov (United States)

    Chen, Qiushui; He, Ziyi; Liu, Wu; Lin, Xuexia; Wu, Jing; Li, Haifang; Lin, Jin-Ming

    2015-10-28

    Paper-supported cell culture is an unprecedented development for advanced bioassays. This study reports a strategy for in vitro engineering of cell-compatible paper chips that allow for adherent cell culture, quantitative assessment of drug efficiency, and label-free sensing of intracellular molecules via paper spray mass spectrometry. The polycarbonate paper is employed as an excellent alternative bioscaffold for cell distribution, adhesion, and growth, as well as allowing for fluorescence imaging without light scattering. The cell-cultured paper chips are thus amenable to fabricate 3D tissue construction and cocultures by flexible deformation, stacks and assembly by layers of cells. As a result, the successful development of cell-compatible paper chips subsequently offers a uniquely flexible approach for in situ sensing of live cell components by paper spray mass spectrometry, allowing profiling the cellular lipids and quantitative measurement of drug metabolism with minimum sample pretreatment. Consequently, the developed paper chips for adherent cell culture are inexpensive for one-time use, compatible with high throughputs, and amenable to label-free and rapid analysis.

  2. CD19-CAR engineered NK-92 cells are sufficient to overcome NK cell resistance in B-cell malignancies.

    Science.gov (United States)

    Romanski, Annette; Uherek, Christoph; Bug, Gesine; Seifried, Erhard; Klingemann, Hans; Wels, Winfried S; Ottmann, Oliver G; Tonn, Torsten

    2016-07-01

    Many B-cell acute and chronic leukaemias tend to be resistant to killing by natural killer (NK) cells. The introduction of chimeric antigen receptors (CAR) into T cells or NK cells could potentially overcome this resistance. Here, we extend our previous observations on the resistance of malignant lymphoblasts to NK-92 cells, a continuously growing NK cell line, showing that anti-CD19-CAR (αCD19-CAR) engineered NK-92 cells can regain significant cytotoxicity against CD19 positive leukaemic cell lines and primary leukaemia cells that are resistant to cytolytic activity of parental NK-92 cells. The 'first generation' CAR was generated from a scFv (CD19) antibody fragment, coupled to a flexible hinge region, the CD3ζ chain and a Myc-tag and cloned into a retrovirus backbone. No difference in cytotoxic activity of NK-92 and transduced αCD19-CAR NK-92 cells towards CD19 negative targets was found. However, αCD19-CAR NK-92 cells specifically and efficiently lysed CD19 expressing B-precursor leukaemia cell lines as well as lymphoblasts from leukaemia patients. Since NK-92 cells can be easily expanded to clinical grade numbers under current Good Manufactoring Practice (cGMP) conditions and its safety has been documented in several phase I clinical studies, treatment with CAR modified NK-92 should be considered a treatment option for patients with lymphoid malignancies.

  3. Transdifferentiation of adipose-derived stem cells into keratinocyte-like cells: engineering a stratified epidermis.

    Directory of Open Access Journals (Sweden)

    Claudia Chavez-Munoz

    Full Text Available Skin regeneration is an important area of research in the field of tissue-engineering, especially for cases involving loss of massive areas of skin, where current treatments are not capable of inducing permanent satisfying replacements. Human adipose-derived stem cells (ASC have been shown to differentiate in-vitro into both mesenchymal lineages and non-mesenchymal lineages, confirming their transdifferentiation ability. This versatile differentiation potential, coupled with their ease of harvest, places ASC at the advancing front of stem cell-based therapies. In this study, we hypothesized that ASC also have the capacity to transdifferentiate into keratinocyte-like cells and furthermore are able to engineer a stratified epidermis. ASC were successfully isolated from lipoaspirates and cell sorted (FACS. After sorting, ASC were either co-cultured with human keratinocytes or with keratinocyte conditioned media. After a 14-day incubation period, ASC developed a polygonal cobblestone shape characteristic of human keratinocytes. Western blot and q-PCR analysis showed the presence of specific keratinocyte markers including cytokeratin-5, involucrin, filaggrin and stratifin in these keratinocyte-like cells (KLC; these markers were absent in ASC. To further evaluate if KLC were capable of stratification akin to human keratinocytes, ASC were seeded on top of human decellularized dermis and cultured in the presence or absence of EGF and high Ca(2+ concentrations. Histological analysis demonstrated a stratified structure similar to that observed in normal skin when cultured in the presence of EGF and high Ca(2+. Furthermore, immunohistochemical analysis revealed the presence of keratinocyte markers such as involucrin, cytokeratin-5 and cytokeratin-10. In conclusion this study demonstrates for the first time that ASC have the capacity to transdifferentiate into KLC and engineer a stratified epidermis. This study suggests that adipose tissue is potentially a

  4. Concise review: cell-based strategies in bone tissue engineering and regenerative medicine

    NARCIS (Netherlands)

    Ma, J.; Both, S.K.; Yang, F.; Cui, F.Z.; Pan, J.; Meijer, G.J.; Jansen, J.A.; Beucken, J.J.J.P van den

    2014-01-01

    Cellular strategies play an important role in bone tissue engineering and regenerative medicine (BTE/RM). Variability in cell culture procedures (e.g., cell types, cell isolation and expansion, cell seeding methods, and preculture conditions before in vivo implantation) may influence experimental ou

  5. Gene editing for cell engineering: trends and applications.

    Science.gov (United States)

    Gupta, Sanjeev K; Shukla, Pratyoosh

    2016-08-18

    Gene editing with all its own advantages in molecular biology applications has made easy manipulation of various production hosts with the discovery and implementation of modern gene editing tools such as Crispr (Clustered regularly interspaced short palindromic repeats), TALENs (Transcription activator-like effector nucleases) and ZFNs (Zinc finger nucleases). With the advent of these modern tools, it is now possible to manipulate the genome of industrial production hosts such as yeast and mammalian cells which allows developing a potential and cost effective recombinant therapeutic protein. These tools also allow single editing to multiple genes for knocking-in or knocking-out of a host genome quickly in an efficient manner. A recent study on "multiplexed" gene editing revolutionized the knock-out and knock-in events of yeast and CHO, mammalian cells genome for metabolic engineering as well as high, stable, and consistent expression of a transgene encoding complex therapeutic protein such as monoclonal antibody. The gene of interest can either be integrated or deleted at single or multiple loci depending on the strategy and production requirement. This review will give a gist of all the modern tools with a brief description and advances in genetic manipulation using three major tools being implemented for the modification of such hosts with the emphasis on the use of Crispr-Cas9 for the "multiplexing gene-editing approach" for genetic manipulation of yeast and CHO mammalian hosts that ultimately leads to a fast track product development with consistent, improved product yield, quality, and thus affordability for a population at large.

  6. An Engineered Herpesvirus Activates Dendritic Cells and Induces Protective Immunity

    Science.gov (United States)

    Ma, Yijie; Chen, Min; Jin, Huali; Prabhakar, Bellur S.; Valyi-Nagy, Tibor; He, Bin

    2017-01-01

    Herpes simplex viruses (HSV) are human pathogens that switch between lytic and latent infection. While attenuated HSV is explored for vaccine, the underlying event remains poorly defined. Here we report that recombinant HSV-1 with a mutation in the γ134.5 protein, a virulence factor, stimulates dendritic cell (DC) maturation which is dependent on TANK-binding kinase 1 (TBK1). When exposed to CD11+ DCs, the mutant virus that lacks the amino terminus of γ134.5 undergoes temporal replication without production of infectious virus. Mechanistically, this leads to sequential phosphorylation of interferon regulatory factor 3 (IRF3) and p65/RelA. In correlation, DCs up-regulate the expression of co-stimulatory molecules and cytokines. However, selective inhibition of TBK1 precludes phosphorylation of IRF3 and subsequent DC activation by the γ134.5 mutant. Herein, the γ134.5 mutant is immune-stimulatory and non-destructive to DCs. Remarkably, upon immunization the γ134.5 mutant induces protection against lethal challenge by the wild type virus, indicative of its vaccine potential. Furthermore, CD11+ DCs primed by the γ134.5 mutant in vivo mediate protection upon adoptive transfer. These results suggest that activation of TBK1 by engineered HSV is crucial for DC maturation, which may contribute to protective immunity. PMID:28150813

  7. CRISPR-Cas9 Genome Engineering in Saccharomyces cerevisiae Cells.

    Science.gov (United States)

    Ryan, Owen W; Poddar, Snigdha; Cate, Jamie H D

    2016-06-01

    This protocol describes a method for CRISPR-Cas9-mediated genome editing that results in scarless and marker-free integrations of DNA into Saccharomyces cerevisiae genomes. DNA integration results from cotransforming (1) a single plasmid (pCAS) that coexpresses the Cas9 endonuclease and a uniquely engineered single guide RNA (sgRNA) expression cassette and (2) a linear DNA molecule that is used to repair the chromosomal DNA damage by homology-directed repair. For target specificity, the pCAS plasmid requires only a single cloning modification: replacing the 20-bp guide RNA sequence within the sgRNA cassette. This CRISPR-Cas9 protocol includes methods for (1) cloning the unique target sequence into pCAS, (2) assembly of the double-stranded DNA repair oligonucleotides, and (3) cotransformation of pCAS and linear repair DNA into yeast cells. The protocol is technically facile and requires no special equipment. It can be used in any S. cerevisiae strain, including industrial polyploid isolates. Therefore, this CRISPR-Cas9-based DNA integration protocol is achievable by virtually any yeast genetics and molecular biology laboratory.

  8. Vascularization and innervation of slits within polydimethylsiloxane sheets in the subcutaneous space of athymic nude mice.

    Science.gov (United States)

    Gurlin, Rachel E; Keating, Mark T; Li, Shiri; Lakey, Jonathan Rt; de Feraudy, Sébastien; Shergill, Bhupinder S; Botvinick, Elliot L

    2017-01-01

    Success of cell therapy in avascular sites will depend on providing sufficient blood supply to transplanted tissues. A popular strategy of providing blood supply is to embed cells within a functionalized hydrogel implanted within the host to stimulate neovascularization. However, hydrogel systems are not always amenable for removal post-transplantation; thus, it may be advantageous to implant a device that contains cells while also providing access to the circulation so retrieval is possible. Here we investigate one instance of providing access to a vessel network, a thin sheet with through-cut slits, and determine if it can be vascularized from autologous materials. We compared the effect of slit width on vascularization of a thin sheet following subcutaneous implantation into an animal model. Polydimethylsiloxane sheets with varying slit widths (approximately 150, 300, 500, or 1500 µm) were fabricated from three-dimensional printed molds. Subcutaneous implantation of sheets in immunodeficient mice revealed that smaller slit widths have evidence of angiogenesis and new tissue growth, while larger slit widths contain native mature tissue squeezing into the space. Our results show that engineered slit sheets may provide a simple approach to cell transplantation by providing a prevascularized and innervated environment.

  9. Genetic engineering of human ES and iPS cells using TALE nucleases

    OpenAIRE

    Hockemeyer, Dirk; Wang, Haoyi; Kiani, Samira; Lai, Christine S.; Gao, Qing; Cassady, John P.; Cost, Gregory J.; Zhang, Lei; Santiago, Yolanda; Miller, Jeffrey C; Zeitler, Bryan; Cherone, Jennifer M.; Meng, Xiangdong; Hinkley, Sarah J; Rebar, Edward J.

    2011-01-01

    Targeted genetic engineering of human pluripotent cells is a prerequisite for exploiting their full potential. Such genetic manipulations can be achieved using site-specific nucleases. Here we engineered transcription activator–like effector nucleases (TALENs) for five distinct genomic loci. At all loci tested we obtained human embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) clones carrying transgenic cassettes solely at the TALEN-specified location. Our data suggest that T...

  10. Treatment of bladder dysfunction using stem cell or tissue engineering technique.

    Science.gov (United States)

    Kim, Jae Heon; Lee, Hong Jun; Song, Yun Seob

    2014-04-01

    Tissue engineering and stem cell transplantation are two important options that may help overcome limitations in the current treatment strategy for bladder dysfunction. Stem cell therapy holds great promise for treating pathophysiology, as well as for urological tissue engineering and regeneration. To date, stem cell therapy in urology has mainly focused on oncology and erectile dysfunction. The therapeutic potency of stem cells (SCs) was originally thought to derive from their ability to differentiate into various cell types including smooth muscle. The main mechanisms of SCs in reconstituting or restoring bladder function are migration, differentiation, and paracrine effects. Nowadays, paracrine effects of stem cells are thought to be more prominent because of their stimulating effects on stem cells and adjacent cells. Studies of stem cell therapy for bladder dysfunction have been limited to experimental models and have been less focused on tissue engineering for bladder regeneration. Bladder outlet obstruction is a representative model. Adipose-derived stem cells, bone marrow stem cells (BMSCs), and skeletal muscle-derived stem cells or muscle precursor cells are used for transplantation to treat bladder dysfunction. The aim of this study is to review stem cell therapy and updated tissue regeneration as treatments for bladder dysfunction and to provide the current status of stem cell therapy and tissue engineering for bladder dysfunction including its mechanisms and limitations.

  11. 拉森钢板桩在太化基坑支护工程中的应用探讨%The application discussion of Larsen steel sheet pile in Taihua foundation pit support engineering

    Institute of Scientific and Technical Information of China (English)

    吴文生

    2014-01-01

    以太化新材料园区工程为例,对工程的水文地质条件进行了分析,确立了钢筋混凝土灌注排桩支护+深层搅拌水泥桩作止水帷幕与拉森钢板桩支护两种基坑支护方案,并对两者作了对比研究,指出拉森钢板桩方案可有效节约成本,缩短施工工期,确保施工安全。%Taking the Taihua new materials industrial park project as an example,this paper analyzed the engineering hydrogeology condition, determined two foundation pit support schemes making reinforced concrete bored piles support + deep mixing cement pile as water curtain and Larssen steel sheet pile support,and made comparative research on both,pointed out that Larsen steel sheet pile scheme could effectively save cost,shorten construction period,ensured the construction safety.

  12. The Effects of Environmental Factors on Smooth Muscle Cells Differentiation from Adipose-Derived Stem Cells and Esophagus Tissues Engineering

    DEFF Research Database (Denmark)

    Wang, Fang

    Adipose-derived stem cells (ASCs) are increasingly being used for regenerative medicine and tissue engineering. Smooth muscle cells (SMCs) can be differentiated from ASCs. Oxygen is a key factor influencing the stem cell differentiation. Tissue engineered esophagus has been a preferred solution...... of esophagus was studied. Our results showed that both SMCs and ASCs could attach on the porcine esophageal acellular matrix (EAM) scaffold in vitro after 24 hours and survive until 7 days. Thus ASCs might be a substitute for SMCs in the construction of tissue engineered esophageal muscle layer....

  13. Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

    Science.gov (United States)

    Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

    2016-05-17

    Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs.

  14. Prototypical model for tensional wrinkling in thin sheets

    KAUST Repository

    Davidovitch, B.

    2011-10-31

    The buckling and wrinkling of thin films has recently seen a surge of interest among physicists, biologists, mathematicians, and engineers. This activity has been triggered by the growing interest in developing technologies at ever-decreasing scales and the resulting necessity to control the mechanics of tiny structures, as well as by the realization that morphogenetic processes, such as the tissue-shaping instabilities occurring in animal epithelia or plant leaves, often emerge from mechanical instabilities of cell sheets. Although the most basic buckling instability of uniaxially compressed plates was understood by Euler more than two centuries ago, recent experiments on nanometrically thin (ultrathin) films have shown significant deviations from predictions of standard buckling theory. Motivated by this puzzle, we introduce here a theoretical model that allows for a systematic analysis of wrinkling in sheets far from their instability threshold. We focus on the simplest extension of Euler buckling that exhibits wrinkles of finite length--a sheet under axisymmetric tensile loads. The first study of this geometry, which is attributed to Lamé, allows us to construct a phase diagram that demonstrates the dramatic variation of wrinkling patterns from near-threshold to far-from-threshold conditions. Theoretical arguments and comparison to experiments show that the thinner the sheet is, the smaller is the compressive load above which the far-from-threshold regime emerges. This observation emphasizes the relevance of our analysis for nanomechanics applications.

  15. Renewable Fuels and Lubricants Laboratory (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-08-01

    This fact sheet describes the Renewable Fuels and Lubricants (ReFUEL) Laboratory at the U.S. Department of Energy National Renewable Energy Laboratory (NREL) is a state-of-the-art research and testing facility for advanced fuels and vehicles. Research and development aims to improve vehicle efficiency and overcome barriers to the increased use of renewable diesel and other nonpetroleum-based fuels, such as biodiesel and synthetic diesel derived from biomass. The ReFUEL Laboratory features a chassis dynamometer for vehicle performance and emissions research, two engine dynamometer test cells for advanced fuels research, and precise emissions analysis equipment. As a complement to these capabilities, detailed studies of fuel properties, with a focus on ignition quality, are performed at NREL's Fuel Chemistry Laboratory.

  16. Innovative methods to use silicon sheets for high efficiency solar cells. Final report; Innovative Verfahren zum Einsatz von Siliciumfolien fuer hocheffiziente Solarzellen. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, W.

    2001-01-01

    This project was organised into three main activity units. The design and test of continuous process equipment and related handling and control systems for multicrystalline and EFG (edge-defined film-fed growth) silicon wafers lead to an important knowledge base for the design of a fully automated (pilot) production line for high efficiency solar cells, specially suited for the application of silicon sheets with their different surface morphology in comparison to conventional sliced silicon wafers. The development of new continuous processing equipment closed the gaps in the design concept of an automated production line to realise a simple process sequence and related innovative continuous processing schemes for the production of high efficiency solar cells from silicon sheets. Based on the results achieved so far, a fully automated pilot production line with continuous processing equipment for all process steps for the production of high efficiency solar cells was set up. The test results demonstrated the suitability of the selected concept for a future mass production in the 50 to 100 MW range: Mean cell efficiencies of 14% for EFG sheets and 14.5-15% for cast multicrystalline silicon wafers were achieved. A thorough cell production cost analysis based on all collected data revealed a 20% reduction in comparison to the former state-of-the-art. (orig.) [German] In diesem Vorhaben wurden drei Arbeitsschwerpunkte bearbeitet. Die Konzeption und Erprobung von Durchlaufanlagen und zugehoerigen Handhabungs- und Steuerungssystemen fuer mc(multikristalline)- und EFG(edge-defined film-fed growth)-Siliciumscheiben lieferte wesentliche Erkenntnisse fuer die Gestaltung einer vollautomatischen Pilotfertigung fuer hocheffiziente Solarzellen, speziell geeignet fuer den Einsatz von Siliciumfolien mit ihrer gegenueber konventionellen gesaegten Siliciumscheiben andersartigen Oberflaechenstruktur. Die Entwicklung neuartiger Durchlaufanlagen schloss die bestehenden Luecken im

  17. Liposome-based engineering of cells to package hydrophobic compounds in membrane vesicles for tumor penetration.

    Science.gov (United States)

    Lee, Junsung; Kim, Jiyoung; Jeong, Moonkyoung; Lee, Hyoungjin; Goh, Unbyeol; Kim, Hyaeyeong; Kim, Byungji; Park, Ji-Ho

    2015-05-13

    Natural membrane vesicles (MVs) derived from various types of cells play an essential role in transporting biological materials between cells. Here, we show that exogenous compounds are packaged in the MVs by engineering the parental cells via liposomes, and the MVs mediate autonomous intercellular migration of the compounds through multiple cancer cell layers. Hydrophobic compounds delivered selectively to the plasma membrane of cancer cells using synthetic membrane fusogenic liposomes were efficiently incorporated into the membrane of MVs secreted from the cells and then transferred to neighboring cells via the MVs. This liposome-mediated MV engineering strategy allowed hydrophobic photosensitizers to significantly penetrate both spheroids and in vivo tumors, thereby enhancing the therapeutic efficacy. These results suggest that innate biological transport systems can be in situ engineered via synthetic liposomes to guide the penetration of chemotherapeutics across challenging tissue barriers in solid tumors.

  18. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    Science.gov (United States)

    Myung, Nosang; Narayanan, Sekharipuram; Wiberg, Dean

    2008-01-01

    Nano-engineered catalysts, and a method of fabricating them, have been developed in a continuing effort to improve the performances of direct methanol fuel cells as candidate power sources to supplant primary and secondary batteries in a variety of portable electronic products. In order to realize the potential for high energy densities (as much as 1.5 W h/g) of direct methanol fuel cells, it will be necessary to optimize the chemical compositions and geometric configurations of catalyst layers and electrode structures. High performance can be achieved when catalyst particles and electrode structures have the necessary small feature sizes (typically of the order of nanometers), large surface areas, optimal metal compositions, high porosity, and hydrophobicity. The present method involves electrodeposition of one or more catalytic metal(s) or a catalytic-metal/polytetrafluoroethylene nanocomposite on an alumina nanotemplate. The alumina nanotemplate is then dissolved, leaving the desired metal or metal/polytetrafluoroethylene-composite catalyst layer. Unlike some prior methods of making fine metal catalysts, this method does not involve processing at elevated temperature; all processing can be done at room temperature. In addition, this method involves fewer steps and is more amenable to scaling up for mass production. Alumina nanotemplates are porous alumina membranes that have been fabricated, variously, by anodizing either pure aluminum or aluminum that has been deposited on silicon by electronbeam evaporation. The diameters of the pores (7 to 300 nm), areal densities of pores (as much as 7 x 10(exp 10)sq cm), and lengths of pores (up to about 100 nm) can be tailored by selection of fabrication conditions. In a given case, the catalytic metal, catalytic metal alloy, or catalytic metal/ polytetrafluoroethylene composite is electrodeposited in the pores of the alumina nanotemplate. The dimensions of the pores, together with the electrodeposition conditions

  19. PDX1-engineered embryonic stem cell-derived insulin producing cells regulate hyperglycemia in diabetic mice

    Directory of Open Access Journals (Sweden)

    Raikwar Sudhanshu P

    2012-10-01

    GFP/RIP-Luc ES cells can be efficiently differentiated in vitro into IPCs. Our new data suggest that R1Pdx1AcGFP/RIP-Luc ES cells efficiently differentiate into glucose responsive IPCs. The ES cell differentiation led to pancreatic lineage commitment and expression of pancreatic β cell-specific genes, including Pax4, Pax6, Ngn3, Isl1, insulin 1, insulin 2 and PC2/3. Transplantation of the IPCs under the kidney capsule led to sustained long-term correction of hyperglycemia in diabetic mice. Although these newly generated IPCs effectively rescued hyperglycemic mice, an unexpected result was teratoma formation in 1 out of 12 mice. We attribute the development of the teratoma to the presence of either non-differentiated or partially differentiated stem cells. Conclusions Our data show the potential of Pdx1-engineered ES cells to enhance pancreatic lineage commitment and to robustly drive the differentiation of ES cells into glucose responsive IPCs. However, there is an unmet need for eliminating the partially differentiated stem cells.

  20. Sheet Bending using Soft Tools

    Science.gov (United States)

    Sinke, J.

    2011-05-01

    Sheet bending is usually performed by air bending and V-die bending processes. Both processes apply rigid tools. These solid tools facilitate the generation of software for the numerical control of those processes. When the lower rigid die is replaced with a soft or rubber tool, the numerical control becomes much more difficult, since the soft tool deforms too. Compared to other bending processes the rubber backed bending process has some distinct advantages, like large radius-to-thickness ratios, applicability to materials with topcoats, well defined radii, and the feasibility of forming details (ridges, beads). These advantages may give the process exclusive benefits over conventional bending processes, not only for industries related to mechanical engineering and sheet metal forming, but also for other disciplines like Architecture and Industrial Design The largest disadvantage is that also the soft (rubber) tool deforms. Although the tool deformation is elastic and recovers after each process cycle, the applied force during bending is related to the deformation of the metal sheet and the deformation of the rubber. The deformation of the rubber interacts with the process but also with sheet parameters. This makes the numerical control of the process much more complicated. This paper presents a model for the bending of sheet materials using a rubber lower die. This model can be implemented in software in order to control the bending process numerically. The model itself is based on numerical and experimental research. In this research a number of variables related to the tooling and the material have been evaluated. The numerical part of the research was used to investigate the influence of the features of the soft lower tool, like the hardness and dimensions, and the influence of the sheet thickness, which also interacts with the soft tool deformation. The experimental research was focused on the relation between the machine control parameters and the most

  1. CRISPR/Cas9 advances engineering of microbial cell factories

    DEFF Research Database (Denmark)

    Jakociunas, Tadas; Jensen, Michael Krogh; Keasling, Jay D.

    2016-01-01

    interspaced palindromic repeats (CRISPR) and its associated proteins (Cas) have become the method of choice for precision genome engineering in many organisms due to their orthogonality, versatility and efficacy. Here we review the strategies adopted for implementation of RNA-guided CRISPR/Cas9 genome editing......-RNAs will be highlighted. Finally, this review will provide a perspective on the immediate challenges and opportunities foreseen by the use of CRISPR/Cas9 genome engineering and regulation in the context of metabolic engineering....

  2. Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering

    NARCIS (Netherlands)

    Jovanovic, Danijela; Roukes, Frans V.; Loeber, Andrea; Engels, Gerwin E.; van Oeveren, Willem; van Seijen, Xavier J. Gallego; van Luyn, Marja J. A.; Harmsen, Martin C.; Schouten, Arend Jan

    2011-01-01

    Polycaprolactone (PCL) polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suit

  3. Biomedical engineers use electric pulses to destroy cancer cells

    OpenAIRE

    Nystrom, Lynn A.

    2007-01-01

    A team of biomedical engineers at Virginia Tech and the University of California at Berkeley has developed a new minimally invasive method of treating cancer, and they anticipate clinical trials on individuals with prostate cancer will begin soon.

  4. Tissue engineered periodontal products.

    Science.gov (United States)

    Bartold, P M; Gronthos, S; Ivanovski, S; Fisher, A; Hutmacher, D W

    2016-02-01

    Attainment of periodontal regeneration is a significant clinical goal in the management of advanced periodontal defects arising from periodontitis. Over the past 30 years numerous techniques and materials have been introduced and evaluated clinically and have included guided tissue regeneration, bone grafting materials, growth and other biological factors and gene therapy. With the exception of gene therapy, all have undergone evaluation in humans. All of the products have shown efficacy in promoting periodontal regeneration in animal models but the results in humans remain variable and equivocal concerning attaining complete biological regeneration of damaged periodontal structures. In the early 2000s, the concept of tissue engineering was proposed as a new paradigm for periodontal regeneration based on molecular and cell biology. At this time, tissue engineering was a new and emerging field. Now, 14 years later we revisit the concept of tissue engineering for the periodontium and assess how far we have come, where we are currently situated and what needs to be done in the future to make this concept a reality. In this review, we cover some of the precursor products, which led to our current position in periodontal tissue engineering. The basic concepts of tissue engineering with special emphasis on periodontal tissue engineering products is discussed including the use of mesenchymal stem cells in bioscaffolds and the emerging field of cell sheet technology. Finally, we look into the future to consider what CAD/CAM technology and nanotechnology will have to offer.

  5. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells

    Directory of Open Access Journals (Sweden)

    Yunfan He

    2016-01-01

    Full Text Available Adipose stem cells have prominent implications in tissue regeneration due to their abundance and relative ease of harvest from adipose tissue and their abilities to differentiate into mature cells of various tissue lineages and secrete various growth cytokines. Development of tissue engineering techniques in combination with various carrier scaffolds and adipose stem cells offers great potential in overcoming the existing limitations constraining classical approaches used in plastic and reconstructive surgery. However, as most tissue engineering techniques are new and highly experimental, there are still many practical challenges that must be overcome before laboratory research can lead to large-scale clinical applications. Tissue engineering is currently a growing field of medical research; in this review, we will discuss the progress in research on biomaterials and scaffolds for tissue engineering applications using adipose stem cells.

  6. Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells.

    Science.gov (United States)

    He, Yunfan; Lu, Feng

    2016-01-01

    Adipose stem cells have prominent implications in tissue regeneration due to their abundance and relative ease of harvest from adipose tissue and their abilities to differentiate into mature cells of various tissue lineages and secrete various growth cytokines. Development of tissue engineering techniques in combination with various carrier scaffolds and adipose stem cells offers great potential in overcoming the existing limitations constraining classical approaches used in plastic and reconstructive surgery. However, as most tissue engineering techniques are new and highly experimental, there are still many practical challenges that must be overcome before laboratory research can lead to large-scale clinical applications. Tissue engineering is currently a growing field of medical research; in this review, we will discuss the progress in research on biomaterials and scaffolds for tissue engineering applications using adipose stem cells.

  7. Efficient derivation and genetic modifications of human pluripotent stem cells on engineered human feeder cell lines.

    Science.gov (United States)

    Zou, Chunlin; Chou, Bin-Kuan; Dowey, Sarah N; Tsang, Kitman; Huang, Xiaosong; Liu, Cyndi F; Smith, Cory; Yen, Jonathan; Mali, Prashant; Zhang, Yu Alex; Cheng, Linzhao; Ye, Zhaohui

    2012-08-10

    Derivation of pluripotent stem cells (iPSCs) induced from somatic cell types and the subsequent genetic modifications of disease-specific or patient-specific iPSCs are crucial steps in their applications for disease modeling as well as future cell and gene therapies. Conventional procedures of these processes require co-culture with primary mouse embryonic fibroblasts (MEFs) to support self-renewal and clonal growth of human iPSCs as well as embryonic stem cells (ESCs). However, the variability of MEF quality affects the efficiencies of all these steps. Furthermore, animal sourced feeders may hinder the clinical applications of human stem cells. In order to overcome these hurdles, we established immortalized human feeder cell lines by stably expressing human telomerase reverse transcriptase, Wnt3a, and drug resistance genes in adult mesenchymal stem cells. Here, we show that these immortalized human feeders support efficient derivation of virus-free, integration-free human iPSCs and long-term expansion of human iPSCs and ESCs. Moreover, the drug-resistance feature of these feeders also supports nonviral gene transfer and expression at a high efficiency, mediated by piggyBac DNA transposition. Importantly, these human feeders exhibit superior ability over MEFs in supporting homologous recombination-mediated gene targeting in human iPSCs, allowing us to efficiently target a transgene into the AAVS1 safe harbor locus in recently derived integration-free iPSCs. Our results have great implications in disease modeling and translational applications of human iPSCs, as these engineered human cell lines provide a more efficient tool for genetic modifications and a safer alternative for supporting self-renewal of human iPSCs and ESCs.

  8. 两种细胞膜片对牙生物性种植体牙周再生影响的动物实验%Periodontal tissue in a bio-implant by periodontal ligament cells sheet and bone marrow stromal cells sheet

    Institute of Scientific and Technical Information of China (English)

    孙传明; 刘宏伟

    2014-01-01

    目的 应用牙周膜细胞(periodontal ligament cells,PDLC)膜片、骨髓基质细胞(bone marrow stromal cells,BMSC)膜片与自体牙根体外构建牙生物性种植体,研究构建具有新生牙周组织支持的生物性牙根的可行性.方法 拔除2只比格犬下颌两侧双尖牙制作缺牙区,将比格犬自体牙根预备成近似圆柱状.培养犬第3代PDLC和BMSC成细胞膜片,体外将PDLC和BMSC膜片单独或共同包裹于牙根表面构建自体牙根种植体,将种植体分为4组:①双膜片组(每只犬2颗),将PDLC、BMSC先后包裹于同一牙根表面;②PDLC膜片组(每只犬2颗),将PDLC单膜片包裹于牙根表面;③BMSC膜片组(每只犬2颗),将BMSC单膜片包裹于牙根表面;④无膜片组(空白对照组)(每只犬1颗),无膜片牙根.制作缺牙区手术8周后,将种植体植入自体缺牙区牙槽嵴,12周时取材制作石蜡切片行HE和Masson三色染色,观察各组切片的组织学结果.结果 PDLC膜片组种植体根面可见包括牙骨质、牙周膜及牙槽骨的牙周组织样结构,其中可见类似牙周穿通纤维样组织垂直插入根面及骨面;双膜片组种植体和BMSC膜片组种植体根面多为骨性结合;空白对照组亦未见牙周组织样结构形成.结论 PDLC膜片能促进牙生物性种植体的牙周再生,可部分再生出包括牙骨质、牙周膜和牙槽骨的复杂牙周组织.%Objective To fabricate the bio-implant supported by regenerated periodontal tissue utilizing periodontal ligament cells(PDLC)-bone marrow stromal cells(BMSC) sheet and natural root.Methods Premolars of 2 beagle dogs were extracted to prepare the implanted area.Autologous tooth roots were carved into cylinders.PDLC and BMSC separated from beagle dogs were cultured into cell sheets in medium.Tooth roots were wrapped by one type of cell sheets or both to fabricate bio-implant and divided into four groups,tooth roots were wrapped by PDLC sheets and BMSC sheets successively (2 samples

  9. Normal human epithelial cells regulate the size and morphology of tissue-engineered capillaries.

    Science.gov (United States)

    Rochon, Marie-Hélène; Fradette, Julie; Fortin, Véronique; Tomasetig, Florence; Roberge, Charles J; Baker, Kathleen; Berthod, François; Auger, François A; Germain, Lucie

    2010-05-01

    The survival of thick tissues/organs produced by tissue engineering requires rapid revascularization after grafting. Although capillary-like structures have been reconstituted in some engineered tissues, little is known about the interaction between normal epithelial cells and endothelial cells involved in the in vitro angiogenic process. In the present study, we used the self-assembly approach of tissue engineering to examine this relationship. An endothelialized tissue-engineered dermal substitute was produced by adding endothelial cells to the tissue-engineered dermal substitute produced by the self-assembly approach. The latter consists in culturing fibroblasts in the medium supplemented with serum and ascorbic acid. A network of tissue-engineered capillaries (TECs) formed within the human extracellular matrix produced by dermal fibroblasts. To determine whether epithelial cells modify TECs, the size and form of TECs were studied in the endothelialized tissue-engineered dermal substitute cultured in the presence or absence of epithelial cells. In the presence of normal keratinocytes from skin, cornea or uterine cervix, endothelial cells formed small TECs (cross-sectional area estimated at less than 50 microm(2)) reminiscent of capillaries found in the skin's microcirculation. In contrast, TECs grown in the absence of epithelial cells presented variable sizes (larger than 50 microm(2)), but the addition of keratinocyte-conditioned media or exogenous vascular endothelial growth factor induced their normalization toward a smaller size. Vascular endothelial growth factor neutralization inhibited the effect of keratinocyte-conditioned media. These results provide new direct evidence that normal human epithelial cells play a role in the regulation of the underlying TEC network, and advance our knowledge in tissue engineering for the production of TEC networks in vitro.

  10. 温度敏感性材料培养的脂肪源性干细胞作为眼表重建种子细胞的可行性研究%Feasibility of adipose tissue-derived stem cell sheet fabricated ex vivo on temperature-responsive scaffolds as seed cells for ocular surface reconstruction

    Institute of Scientific and Technical Information of China (English)

    韦巧玲; 徐建江

    2015-01-01

    子显微镜下观察可见ADSCs和OMECs表面均有致密的上皮微绒毛结构,细胞间连接紧密.结论 自制的TRSs可作为脂肪干细胞的培养支架,ADSCs取材广泛,TRSs上培养的ADSCs层片细胞活力好,可操作性强,可作为眼表重建新的种子来源.%Background Development of corneal tissue engineering creates a new therapeutic method for severe corneal diseases.However,ideal seed cells and scaffold for corneal surface reconstruction have not yet been investigated well.Adipose-derived stem cells (ADSCs) are varified to have a self-renewal ability and epithelioid features,and temperature-responsive scaffolds (TRSs) can offer technical support for stem cell sheet.Objective This study was to investigate the characteristics of ADSCs cultured on TRSs and compare these features to typical oral mucosal epithelial cells (OMECs),and therefore to explore the feasibility of reconstruction of ocular surface with ADSCs as seed cells.Methods Self-made TRSs were prepared by adding isopropyl alcohol dissolved poly-Nisopropylacrylamide (PNIPAAm) to each polystyrene tissue culture dish and then irradiating using an election beam.Subcutaneious fatty tissue of rabbit neck was obtained to culture ADSCs,and 4 pieces of oral cavity mucosal tissue were digested and cultured to obtain OMECs.Then the ADSCs and OMECs were incubated on TRSs,and cell morphology,growth rate,detached duration and survival counts were compared between ADSCs and OMECs.The ADSCs sheet and OMECs sheet were stained with hematoxylin and eosin for morphological examination.Immunochemistry was used to observe the expressions of stem-cell biomakers and epithelioid-cell biomakers in the cells.The ultrastructure of cell surface was observed under the scanning electron microscope.Results Self-made TRSs were similar to ordinary culture dish in the transparancy and smoothness.The water contact angle of 4 in 5 samples were >10° with the effective rate upto 80%.A DSCs showed the elongated

  11. Fibrin Gel as an Injectable Biodegradable Scaffold and Cell Carrier for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Yuting Li

    2015-01-01

    Full Text Available Due to the increasing needs for organ transplantation and a universal shortage of donated tissues, tissue engineering emerges as a useful approach to engineer functional tissues. Although different synthetic materials have been used to fabricate tissue engineering scaffolds, they have many limitations such as the biocompatibility concerns, the inability to support cell attachment, and undesirable degradation rate. Fibrin gel, a biopolymeric material, provides numerous advantages over synthetic materials in functioning as a tissue engineering scaffold and a cell carrier. Fibrin gel exhibits excellent biocompatibility, promotes cell attachment, and can degrade in a controllable manner. Additionally, fibrin gel mimics the natural blood-clotting process and self-assembles into a polymer network. The ability for fibrin to cure in situ has been exploited to develop injectable scaffolds for the repair of damaged cardiac and cartilage tissues. Additionally, fibrin gel has been utilized as a cell carrier to protect cells from the forces during the application and cell delivery processes while enhancing the cell viability and tissue regeneration. Here, we review the recent advancement in developing fibrin-based biomaterials for the development of injectable tissue engineering scaffold and cell carriers.

  12. Surface functionalization of nanobiomaterials for application in stem cell culture, tissue engineering, and regenerative medicine.

    Science.gov (United States)

    Rana, Deepti; Ramasamy, Keerthana; Leena, Maria; Jiménez, Constanza; Campos, Javier; Ibarra, Paula; Haidar, Ziyad S; Ramalingam, Murugan

    2016-05-01

    Stem cell-based approaches offer great application potential in tissue engineering and regenerative medicine owing to their ability of sensing the microenvironment and respond accordingly (dynamic behavior). Recently, the combination of nanobiomaterials with stem cells has paved a great way for further exploration. Nanobiomaterials with engineered surfaces could mimic the native microenvironment to which the seeded stem cells could adhere and migrate. Surface functionalized nanobiomaterial-based scaffolds could then be used to regulate or control the cellular functions to culture stem cells and regenerate damaged tissues or organs. Therefore, controlling the interactions between nanobiomaterials and stem cells is a critical factor. However, surface functionalization or modification techniques has provided an alternative approach for tailoring the nanobiomaterials surface in accordance to the physiological surrounding of a living cells; thereby, enhancing the structural and functional properties of the engineered tissues and organs. Currently, there are a variety of methods and technologies available to modify the surface of biomaterials according to the specific cell or tissue properties to be regenerated. This review highlights the trends in surface modification techniques for nanobiomaterials and the biological relevance in stem cell-based tissue engineering and regenerative medicine. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:554-567, 2016.

  13. Diabetes Fact Sheet

    Science.gov (United States)

    ... diabetes by losing weight. Related information Fitness and nutrition Heart disease and stroke Obesity and weight loss fact sheet Physical activity fact sheet Pregnancy The javascript used in this widget is not ...

  14. Zika Virus Fact Sheet

    Science.gov (United States)

    ... sheets Fact files Questions & answers Features Multimedia Contacts Zika virus Fact sheet Updated 6 September 2016 Key ... and last for 2-7 days. Complications of Zika virus disease Based on a systematic review of ...

  15. Pharmacogenomics Fact Sheet

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Pharmacogenomics Fact Sheet Pharmacogenomics Fact Sheet Tagline (Optional) Middle/Main Content Area What is pharmacogenomics? Pharmacogenomics (sometimes called pharmacogenetics) is a field of ...

  16. Structural Biology Fact Sheet

    Science.gov (United States)

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  17. Fetal and adult liver stem cells for liver regeneration and tissue engineering.

    Science.gov (United States)

    Fiegel, H C; Lange, Claudia; Kneser, U; Lambrecht, W; Zander, A R; Rogiers, X; Kluth, D

    2006-01-01

    For the development of innovative cell-based liver directed therapies, e.g. liver tissue engineering, the use of stem cells might be very attractive to overcome the limitation of donor liver tissue. Liver specific differentiation of embryonic, fetal or adult stem cells is currently under investigation. Different types of fetal liver (stem) cells during development were identified, and their advantageous growth potential and bipotential differentiation capacity were shown. However, ethical and legal issues have to be addressed before using fetal cells. Use of adult stem cells is clinically established, e.g. transplantation of hematopoietic stem cells. Other bone marrow derived liver stem cells might be mesenchymal stem cells (MSC). However, the transdifferentiation potential is still in question due to the observation of cellular fusion in several in vivo experiments. In vitro experiments revealed a crucial role of the environment (e.g. growth factors and extracellular matrix) for specific differentiation of stem cells. Co-cultured liver cells also seemed to be important for hepatic gene expression of MSC. For successful liver cell transplantation, a novel approach of tissue engineering by orthotopic transplantation of gel-immobilized cells could be promising, providing optimal environment for the injected cells. Moreover, an orthotopic tissue engineering approach using bipotential stem cells could lead to a repopulation of the recipients liver with healthy liver and biliary cells, thus providing both hepatic functions and biliary excretion. Future studies have to investigate, which stem cell and environmental conditions would be most suitable for the use of stem cells for liver regeneration or tissue engineering approaches.

  18. Engineering PQS biosynthesis pathway for enhancement of bioelectricity production in Pseudomonas aeruginosa microbial fuel cells

    DEFF Research Database (Denmark)

    Wang, Victor Bochuan; Chua, Song-Lin; Cao, Bin;

    2013-01-01

    . aeruginosa strain that produces higher concentrations of phenazines under anaerobic conditions by over-expressing the PqsE effector in a PQS negative ΔpqsC mutant. The engineered strain exhibited an improved electrical performance in microbial fuel cells (MFCs) and potentiostat-controlled electrochemical...... cells with an approximate five-fold increase of maximum current density relative to the parent strain. Electrochemical analysis showed that the current increase correlates with an over-synthesis of phenazines. These results therefore demonstrate that targeting microbial cell-to-cell communication...... by genetic engineering is a suitable technique to improve power output of bioelectrochemical systems....

  19. Bidirectional Promoter Engineering for Single Cell MicroRNA Sensors in Embryonic Stem Cells.

    Science.gov (United States)

    Sladitschek, Hanna L; Neveu, Pierre A

    2016-01-01

    MicroRNAs have emerged as important markers and regulators of cell identity. Precise measurements of cellular miRNA levels rely traditionally on RNA extraction and thus do not allow to follow miRNA expression dynamics at the level of single cells. Non-invasive miRNA sensors present an ideal solution but they critically depend on the performance of suitable ubiquitous promoters that reliably drive expression both in pluripotent and differentiated cell types. Here we describe the engineering of bidirectional promoters that drive the expression of precise ratiometric fluorescent miRNA sensors in single mouse embryonic stem cells (mESCs) and their differentiated derivatives. These promoters are based on combinations of the widely used CAG, EF1α and PGK promoters as well as the CMV and PGK enhancers. miR-142-3p, which is known to be bimodally expressed in mESCs, served as a model miRNA to gauge the precision of the sensors. The performance of the resulting miRNA sensors was assessed by flow cytometry in single stable transgenic mESCs undergoing self-renewal or differentiation. EF1α promoters arranged back-to-back failed to drive the robustly correlated expression of two transgenes. Back-to-back PGK promoters were shut down during mESC differentiation. However, we found that a back-to-back arrangement of CAG promoters with four CMV enhancers provided both robust expression in mESCs undergoing differentiation and the best signal-to-noise for measurement of miRNA activity in single cells among all the sensors we tested. Such a bidirectional promoter is therefore particularly well suited to study the dynamics of miRNA expression during cell fate transitions at the single cell level.

  20. Bidirectional Promoter Engineering for Single Cell MicroRNA Sensors in Embryonic Stem Cells.

    Directory of Open Access Journals (Sweden)

    Hanna L Sladitschek

    Full Text Available MicroRNAs have emerged as important markers and regulators of cell identity. Precise measurements of cellular miRNA levels rely traditionally on RNA extraction and thus do not allow to follow miRNA expression dynamics at the level of single cells. Non-invasive miRNA sensors present an ideal solution but they critically depend on the performance of suitable ubiquitous promoters that reliably drive expression both in pluripotent and differentiated cell types. Here we describe the engineering of bidirectional promoters that drive the expression of precise ratiometric fluorescent miRNA sensors in single mouse embryonic stem cells (mESCs and their differentiated derivatives. These promoters are based on combinations of the widely used CAG, EF1α and PGK promoters as well as the CMV and PGK enhancers. miR-142-3p, which is known to be bimodally expressed in mESCs, served as a model miRNA to gauge the precision of the sensors. The performance of the resulting miRNA sensors was assessed by flow cytometry in single stable transgenic mESCs undergoing self-renewal or differentiation. EF1α promoters arranged back-to-back failed to drive the robustly correlated expression of two transgenes. Back-to-back PGK promoters were shut down during mESC differentiation. However, we found that a back-to-back arrangement of CAG promoters with four CMV enhancers provided both robust expression in mESCs undergoing differentiation and the best signal-to-noise for measurement of miRNA activity in single cells among all the sensors we tested. Such a bidirectional promoter is therefore particularly well suited to study the dynamics of miRNA expression during cell fate transitions at the single cell level.

  1. CRISPR/Cas9 advances engineering of microbial cell factories.

    Science.gov (United States)

    Jakočiūnas, Tadas; Jensen, Michael K; Keasling, Jay D

    2016-03-01

    One of the key drivers for successful metabolic engineering in microbes is the efficacy by which genomes can be edited. As such there are many methods to choose from when aiming to modify genomes, especially those of model organisms like yeast and bacteria. In recent years, clustered regularly interspaced palindromic repeats (CRISPR) and its associated proteins (Cas) have become the method of choice for precision genome engineering in many organisms due to their orthogonality, versatility and efficacy. Here we review the strategies adopted for implementation of RNA-guided CRISPR/Cas9 genome editing with special emphasis on their application for metabolic engineering of yeast and bacteria. Also, examples of how nuclease-deficient Cas9 has been applied for RNA-guided transcriptional regulation of target genes will be reviewed, as well as tools available for computer-aided design of guide-RNAs will be highlighted. Finally, this review will provide a perspective on the immediate challenges and opportunities foreseen by the use of CRISPR/Cas9 genome engineering and regulation in the context of metabolic engineering.

  2. The investigation of human periodontal ligament cell-sheet in vitro%人牙周韧带细胞膜片的体外实验研究

    Institute of Scientific and Technical Information of China (English)

    张剑英; 付云; 俞少杰

    2013-01-01

    Objective To investigate human periodontal ligament cells' capacities of osteogenesis and adipogenesis,and to identify the expression of type-Ⅰ collagen,laminin and fibronectin which are the main components of extracellular matrix in human periodontal ligament cell sheet through establish cell sheet model in vitro experiment.Methods Human periondontal ligament cells were purified and cultured by using enzymes digesting/tissue culture method.Immunocytochemistry was applied to identify the source and putative stem-cell marker STRO-1 of hPDLCs.The second to fourth passages of hPDLCs were cultured in the osteogenic medium and adipogenic medium for indicated days.Alizarin red and Oil red O staining method were applied to identify capabilities of osteogenesis and adipogenesis of hPDLCs.Haematoxylin-eosin staining and immunohistochemistry were applied to identify expression of type-Ⅰ collagen,laminin and fibronectin in hPDLCs cell sheet.Results The cultured hPDLCs demonstrated extensive proliferation and could be expanded in vitro.Immunostaining demonstrated that the cells expressed intermediate filament protein vimentin and the mesenchymal stem-cell marker STRO-1.hPDLCs in the osteogenic medium formed alizarin red-positive nodules.When hPDLCs were incubated in adipogenic medium,the cells developed into oil red O-positive lipid clusters and a significant high expression of type-Ⅰ collagen,laminin and fibronectin in human periodontalligament cell sheet.Conclusions Our findings confirm that hPDLCs contained stem cells population from culture,source identification,expression of the mesenchymai stem cell marker STRO-1,multilineage differentiation potent under defined culture conditions.Our study indicates that the hPDLCs turn out to be an efficient source and cell sheet to be an excellent bio-material that can be used for periodontal tissue regeneration.%目的 观察体外培养人牙周韧带细胞(hPDLCs)的成骨、成脂能力;构建hPDLCs膜片并鉴定膜片

  3. Advances in tissue engineering through stem cell-based co-culture.

    Science.gov (United States)

    Paschos, Nikolaos K; Brown, Wendy E; Eswaramoorthy, Rajalakshmanan; Hu, Jerry C; Athanasiou, Kyriacos A

    2015-05-01

    Stem cells are the future in tissue engineering and regeneration. In a co-culture, stem cells not only provide a target cell source with multipotent differentiation capacity, but can also act as assisting cells that promote tissue homeostasis, metabolism, growth and repair. Their incorporation into co-culture systems seems to be important in the creation of complex tissues or organs. In this review, critical aspects of stem cell use in co-culture systems are discussed. Direct and indirect co-culture methodologies used in tissue engineering are described, along with various characteristics of cellular interactions in these systems. Direct cell-cell contact, cell-extracellular matrix interaction and signalling via soluble factors are presented. The advantages of stem cell co-culture strategies and their applications in tissue engineering and regenerative medicine are portrayed through specific examples for several tissues, including orthopaedic soft tissues, bone, heart, vasculature, lung, kidney, liver and nerve. A concise review of the progress and the lessons learned are provided, with a focus on recent developments and their implications. It is hoped that knowledge developed from one tissue can be translated to other tissues. Finally, we address challenges in tissue engineering and regenerative medicine that can potentially be overcome via employing strategies for stem cell co-culture use.

  4. Engineering Escherichia coli Cell Factories for n-Butanol Production.

    Science.gov (United States)

    Dong, Hongjun; Zhao, Chunhua; Zhang, Tianrui; Lin, Zhao; Li, Yin; Zhang, Yanping

    2016-01-01

    The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies.

  5. Adult stem cell-based tissue engineered blood vessels: a review.

    Science.gov (United States)

    Krawiec, Jeffrey T; Vorp, David A

    2012-04-01

    With the high occurrence of cardiovascular disease and increasing numbers of patients requiring vascular access, there is a significant need for a small-diameter (adult stem cells can address limitations previously realized in the use of terminally differentiated vascular cells, without introducing the ethical concerns that continue to limit the exploration and use of embryonic stem cells. This review summarizes the exciting work that has been reported on the application of adult stem cells to tissue engineered vascular grafts. Work in this area to date has employed bone marrow mononuclear progenitor cells, mesenchymal stem cells from various sources, and endothelial precursor cells.

  6. Cancer cell-oriented migration of mesenchymal stem cells engineered with an anticancer gene (PTEN: an imaging demonstration

    Directory of Open Access Journals (Sweden)

    Yang ZS

    2014-03-01

    Full Text Available Zhuo-Shun Yang,1,* Xiang-Jun Tang,2,* Xing-Rong Guo,1 Dan-Dan Zou,1 Xu-Yong Sun,3 Jing-Bo Feng,1 Jie Luo,1 Long-Jun Dai,1,4 Garth L Warnock4 1Hubei Key Laboratory of Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 2Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China; 3Guangxi Key Laboratory for Transplant Medicine, 303 Hospital of PLA, Nanning, People’s Republic of China; 4Department of Surgery, University of British Columbia, Vancouver, BC, Canada *These authors contributed equally to this work Background: Mesenchymal stem cells (MSCs have been considered to hold great potential as ideal carriers for the delivery of anticancer agents since the discovery of their tumor tropism. This study was performed to demonstrate the effects of phosphatase and tensin homolog (PTEN engineering on MSCs’ capacity for cancer cell-oriented migration. Methods: MSCs were engineered with a PTEN-bearing plasmid and the expression was confirmed with Western blotting. A human glioma cell line (DBTRG was used as the target cell; DBTRG cell-oriented migration of MSCs was monitored with a micro speed photographic system. Results: The expression of transfected PTEN in MSCs was identified by immunoblotting analysis and confirmed with cell viability assessment of target cells. The DBTRG cell-oriented migration of PTEN-engineered MSCs was demonstrated by a real-time dynamic monitoring system, and a phagocytosis-like action of MSCs was also observed. Conclusion: MSCs maintained their capacity for cancer cell-directed migration after they were engineered with anticancer genes. This study provides the first direct evidence of MSCs’ tropism post-anticancer gene engineering. Keywords: gene therapy, mesenchymal stem cells, phosphatase and tensin homolog, cancer

  7. Engineered nanomaterial uptake and tissue distribution: from cell to organism

    Directory of Open Access Journals (Sweden)

    Kettiger H

    2013-08-01

    Full Text Available Helene Kettiger,1,* Angela Schipanski,2,* Peter Wick,2 Jörg Huwyler1 1Department of Pharmaceutical Sciences, Division of Pharmaceutical Technology, University of Basel, Basel, Switzerland; 2Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Materials-Biology Interactions, St Gallen, Switzerland *These authors contributed equally to this work Abstract: Improved understanding of interactions between nanoparticles and biological systems is needed to develop safety standards and to design new generations of nanomaterials. This article reviews the molecular mechanisms of cellular uptake of engineered nanoparticles, their intracellular fate, and their distribution within an organism. We have reviewed the available literature on the uptake and disposition of engineered nanoparticles. Special emphasis was placed on the analysis of experimental systems and their limitations with respect to their usefulness to predict the in vivo situation. The available literature confirms the need to study particle characteristics in an environment that simulates the situation encountered in biological systems. Phenomena such as protein binding and opsonization are of prime importance since they may have a strong impact on cellular internalization, biodistribution, and immunogenicity of nanoparticles in vitro and in vivo. Extrapolation from in vitro results to the in vivo situation in the whole organism remains a challenge. However, improved understanding of physicochemical properties of engineered nanoparticles and their influence on biological systems facilitates the design of nanomaterials that are safe, well tolerated, and suitable for diagnostic or therapeutic use in humans. Keywords: biodistribution, cellular transport, cellular uptake, endocytosis, engineered nanomaterials, nanosafety

  8. Engineering a cyanobacterial cell factory for production of lactic acid.

    NARCIS (Netherlands)

    Angermayr, S.A.; Paszota, M.; Hellingwerf, K.J.

    2012-01-01

    Metabolic engineering of microorganisms has become a versatile tool to facilitate production of bulk chemicals, fuels, etc. Accordingly, CO(2) has been exploited via cyanobacterial metabolism as a sustainable carbon source of biofuel and bioplastic precursors. Here we extended these observations by

  9. Mathematical modelling of cell aggregation in liver tissue engineering

    OpenAIRE

    Green, John Edward E.

    2006-01-01

    A promising method for growing functional liver tissue in vitro involves culturing hepatocytes as spheroidal cell aggregates. In this thesis, we develop mathematical models of cell aggregation, and use them to determine how hepatocytes' interactions with the extracellular matrix (ECM) on which they are seeded, and with stellate cells, affect the process. Chapters 2-4 focus on the effect that cell-ECM coupling has on the aggregation process. We use a novel formulation that couples a mechani...

  10. Method to determine factors contributing to thermoplastic sheet shrinkage

    Science.gov (United States)

    Rensch, Greg J.; Frye, Brad A.

    A test method is presented for the determination of shrinkage behavior in vacuum-formed thermoplastic resin sheeting, as presently simulated for various resin lots, sheet-gage thicknesses, sheet orientations, and mold profiles. The thermoforming machine and vacuum-forming mold characteristics are discussed. It is established that the four variable factors exert statistically significant effects on the shrinkage response of three Declar resin lots, but that these are of no real practical significance for either engineering or manufacturing operations.

  11. Control of stem cell fate by engineering their micro andnanoenvironment

    Institute of Scientific and Technical Information of China (English)

    Michelle F Griffin; Peter E Butler; Alexander M Seifalian; Deepak M Kalaskar

    2015-01-01

    Stem cells are capable of long-term self-renewal anddifferentiation into specialised cell types, making theman ideal candidate for a cell source for regenerativemedicine. The control of stem cell fate has become amajor area of interest in the field of regenerative medicineand therapeutic intervention. Conventional methodsof chemically inducing stem cells into specific lineagesis being challenged by the advances in biomaterialtechnology, with evidence highlighting that materialproperties are capable of driving stem cell fate. Materialsare being designed to mimic the clues stem cells receivein their in vivo stem cell niche including topographicaland chemical instructions. Nanotopographical clues thatmimic the extracellular matrix (ECM) in vivo have shownto regulate stem cell differentiation. The delivery of ECMcomponents on biomaterials in the form of short peptidessequences has also proved successful in directing stem celllineage. Growth factors responsible for controlling stemcell fate in vivo have also been delivered via biomaterialsto provide clues to determine stem cell differentiation. Analternative approach to guide stem cells fate is to providegenetic clues including delivering DNA plasmids andsmall interfering RNAs via scaffolds. This review, aims toprovide an overview of the topographical, chemical andmolecular clues that biomaterials can provide to guidestem cell fate. The promising features and challenges ofsuch approaches will be highlighted, to provide directionsfor future advancements in this exciting area of stem celltranslation for regenerative medicine.

  12. Engineering T cell immunity by TCR gene transfer

    NARCIS (Netherlands)

    Linnemann, Carsten

    2013-01-01

    T cell responses against tumor-antigens are frequently observed for some human malignancies, in particular melanoma. However, the spontaneous development of T cell responses of a sufficient strength to eradicate human malignancies is rare. The transfer of T cell receptor (TCR) αβ genes into autologo

  13. Clean, Efficient, and Reliable Heat and Power for the 21st Century, Fuel Cell Technologies Program (FCTP) (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-05-01

    This overview of the U.S. Department of Energy's Fuel Cell Technologies Program describes the program's focus and goals, along with current fuel cell applications and future potential. The program focuses on research and development of fuel cell systems for diverse applications in the stationary power, portable power, and transportation sectors. It works to reduce costs and improve technologies to advance fuel cell uses in areas such as combined heat and power, auxiliary power units, portable power systems, and stationary and backup power. To help ensure that fuel cell advances are realized, the program rigorously analyzes energy efficiency, economic, and environmental benefits of fuel cells and seeks to optimize synergies among fuel cell applications and other renewable technologies.

  14. Photovoltaics Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-01

    This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

  15. Cell-Biomaterial Mechanical Interaction in the Framework of Tissue Engineering: Insights, Computational Modeling and Perspectives

    Directory of Open Access Journals (Sweden)

    Esther Reina-Romo

    2011-11-01

    Full Text Available Tissue engineering is an emerging field of research which combines the use of cell-seeded biomaterials both in vitro and/or in vivo with the aim of promoting new tissue formation or regeneration. In this context, how cells colonize and interact with the biomaterial is critical in order to get a functional tissue engineering product. Cell-biomaterial interaction is referred to here as the phenomenon involved in adherent cells attachment to the biomaterial surface, and their related cell functions such as growth, differentiation, migration or apoptosis. This process is inherently complex in nature involving many physico-chemical events which take place at different scales ranging from molecular to cell body (organelle levels. Moreover, it has been demonstrated that the mechanical environment at the cell-biomaterial location may play an important role in the subsequent cell function, which remains to be elucidated. In this paper, the state-of-the-art research in the physics and mechanics of cell-biomaterial interaction is reviewed with an emphasis on focal adhesions. The paper is focused on the different models developed at different scales available to simulate certain features of cell-biomaterial interaction. A proper understanding of cell-biomaterial interaction, as well as the development of predictive models in this sense, may add some light in tissue engineering and regenerative medicine fields.

  16. Cell-Biomaterial Mechanical Interaction in the Framework of Tissue Engineering: Insights, Computational Modeling and Perspectives

    Science.gov (United States)

    Sanz-Herrera, Jose A.; Reina-Romo, Esther

    2011-01-01

    Tissue engineering is an emerging field of research which combines the use of cell-seeded biomaterials both in vitro and/or in vivo with the aim of promoting new tissue formation or regeneration. In this context, how cells colonize and interact with the biomaterial is critical in order to get a functional tissue engineering product. Cell-biomaterial interaction is referred to here as the phenomenon involved in adherent cells attachment to the biomaterial surface, and their related cell functions such as growth, differentiation, migration or apoptosis. This process is inherently complex in nature involving many physico-chemical events which take place at different scales ranging from molecular to cell body (organelle) levels. Moreover, it has been demonstrated that the mechanical environment at the cell-biomaterial location may play an important role in the subsequent cell function, which remains to be elucidated. In this paper, the state-of-the-art research in the physics and mechanics of cell-biomaterial interaction is reviewed with an emphasis on focal adhesions. The paper is focused on the different models developed at different scales available to simulate certain features of cell-biomaterial interaction. A proper understanding of cell-biomaterial interaction, as well as the development of predictive models in this sense, may add some light in tissue engineering and regenerative medicine fields. PMID:22174660

  17. Efficient CRISPR/Cas9-Based Genome Engineering in Human Pluripotent Stem Cells.

    Science.gov (United States)

    Kime, Cody; Mandegar, Mohammad A; Srivastava, Deepak; Yamanaka, Shinya; Conklin, Bruce R; Rand, Tim A

    2016-01-01

    Human pluripotent stem cells (hPS cells) are rapidly emerging as a powerful tool for biomedical discovery. The advent of human induced pluripotent stem cells (hiPS cells) with human embryonic stem (hES)-cell-like properties has led to hPS cells with disease-specific genetic backgrounds for in vitro disease modeling and drug discovery as well as mechanistic and developmental studies. To fully realize this potential, it will be necessary to modify the genome of hPS cells with precision and flexibility. Pioneering experiments utilizing site-specific double-strand break (DSB)-mediated genome engineering tools, including zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), have paved the way to genome engineering in previously recalcitrant systems such as hPS cells. However, these methods are technically cumbersome and require significant expertise, which has limited adoption. A major recent advance involving the clustered regularly interspaced short palindromic repeats (CRISPR) endonuclease has dramatically simplified the effort required for genome engineering and will likely be adopted widely as the most rapid and flexible system for genome editing in hPS cells. In this unit, we describe commonly practiced methods for CRISPR endonuclease genomic editing of hPS cells into cell lines containing genomes altered by insertion/deletion (indel) mutagenesis or insertion of recombinant genomic DNA.

  18. Human Cardiac Tissue Engineering: From Pluripotent Stem Cells to Heart Repair

    Science.gov (United States)

    Jackman, Christopher P.; Shadrin, Ilya Y.; Carlson, Aaron L.; Bursac, Nenad

    2014-01-01

    Engineered cardiac tissues hold great promise for use in drug and toxicology screening, in vitro studies of human physiology and disease, and as transplantable tissue grafts for myocardial repair. In this review, we discuss recent progress in cell-based therapy and functional tissue engineering using pluripotent stem cell-derived cardiomyocytes and we describe methods for delivery of cells into the injured heart. While significant hurdles remain, notable advances have been made in the methods to derive large numbers of pure human cardiomyocytes, mature their phenotype, and produce and implant functional cardiac tissues, bringing the field a step closer to widespread in vitro and in vivo applications. PMID:25599018

  19. Genetic engineering of human embryonic stem cells with lentiviral vectors.

    Science.gov (United States)

    Xiong, Chen; Tang, Dong-Qi; Xie, Chang-Qing; Zhang, Li; Xu, Ke-Feng; Thompson, Winston E; Chou, Wayne; Gibbons, Gary H; Chang, Lung-Ji; Yang, Li-Jun; Chen, Yuqing E

    2005-08-01

    Human embryonic stem (hES) cells present a valuable source of cells with a vast therapeutic potential. However, the low efficiency of directed differentiation of hES cells remains a major obstacle in their uses for regenerative medicine. While differentiation may be controlled by the genetic manipulation, effective and efficient gene transfer into hES cells has been an elusive goal. Here, we show stable and efficient genetic manipulations of hES cells using lentiviral vectors. This method resulted in the establishment of stable gene expression without loss of pluripotency in hES cells. In addition, lentiviral vectors were effective in conveying the expression of an U6 promoter-driven small interfering RNA (siRNA), which was effective in silencing its specific target. Taken together, our results suggest that lentiviral gene delivery holds great promise for hES cell research and application.

  20. [Micro/nano-engineering to control growth of neuronal cells and tissue engineering applied to the central nervous system].

    Science.gov (United States)

    Béduer, Amélie; Vaysse, Laurence; Loubinoux, Isabelle; Vieu, Christophe

    2013-01-01

    Central nervous system pathologies are often characterized by the loss of cell populations. A promising therapy now being developed consists in using bioactive materials, associating grafted cells to biopolymers which provide a scaffold for the in vitro building of new tissues, to be implanted in vivo. In the present article, the state of the art of this field, at crossroads between microtechnology and neuroscience, is described in detail; thereafter our own approach and results about interactions between adult human neural stem cells and microstructured polymers are summarized and discussed. In a second part, some central nervous system repair strategies, based on cerebral tissue engineering, are presented. We will report the main results of our studies to work out and characterize in vivo a cerebral bioprosthesis.

  1. Tooth engineering: searching for dental mesenchymal cells sources.

    Directory of Open Access Journals (Sweden)

    Laetitia eKeller

    2011-03-01

    Full Text Available The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at ED14 allowed making full teeth with crown, root, periodontal ligament fibers and bone. Although representing valuable tools to set up methodologies embryonic cells are not easily available. This work thus aimed to replace the embryonic cells by dental mesenchymal cell lines or cultured expanded embryonic cells, and to test their ability to mediate tooth development in vitro when re-associated with a competent dental epithelium. Histology, immunostaining and RT-PCR allowed getting complementary sets of results. Two different immortalized cell lines from ED18 dental mesenchyme failed in mediating tooth formation. The potentialities of embryonic dental mesenchymal cells decreased from ED14 to ED16 and were lost at ED18. This is likely related to a change in the mesenchymal cell phenotype and/or populations during development. Attempts to cultivate ED14 or ED16 embryonic dental mesenchymal cells prior to re-association led to the loss of their ability to support tooth development. This was accompanied by a down-regulation of Fgf3 transcription. Supplementation of the culture medium with FGF2 allowed restoring Fgf3 expression, but not the ability of mesenchymal cells to engage in tooth formation. Altogether, these observations suggest that a competent cell population exists in the dental mesenchyme at ED14, progressively decreases during development, and cannot as such be maintained in vitro. This study evidenced the need for specific conditions to maintain the ability of dental mesenchymal cells to initiate whole tooth formation, when re-associated with an odontogenic epithelium. Efforts to improve the culture conditions will have to be combined with attempts to characterize the competent cells within the dental mesenchyme.

  2. Cell patch seeding and functional analysis of cellularized scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P R Anil [Division of Implant Biology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala 695012 (India); Varma, H K [Bioceramics Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala 695012 (India); Kumary, T V [Division of Implant Biology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala 695012 (India)

    2007-03-01

    Cell seeding has a direct impact on the final structure and function of tissue constructs, especially for applications like tissue engineering and regeneration. In this study seeding cell patches retrieved from the thermoresponsive poly(N-isopropylacrylamide) surface were used to generate in vitro tissue constructs. Porous and dense bone substitute materials were cellularized using osteoblast cells by a patch transfer and a trypsin method. The function and proliferation of cells was analyzed after 7 days of culture. The relative cell growth rate was found to be higher in cellularized porous hydroxyapatite (PHA) than in dense hydroxyapatite. Live-dead staining confirmed viable cells inside the pores of PHA. Increased alkaline phosphatase activity of cells transferred by the cell patch over the trypsin method revealed the significance of cell patch seeding. This novel method of generating tissue constructs by cell patch seeding was successful in cellularizing scaffolds with intact cell function.

  3. Cell patch seeding and functional analysis of cellularized scaffolds for tissue engineering.

    Science.gov (United States)

    Anil Kumar, P R; Varma, H K; Kumary, T V

    2007-03-01

    Cell seeding has a direct impact on the final structure and function of tissue constructs, especially for applications like tissue engineering and regeneration. In this study seeding cell patches retrieved from the thermoresponsive poly(N-isopropylacrylamide) surface were used to generate in vitro tissue constructs. Porous and dense bone substitute materials were cellularized using osteoblast cells by a patch transfer and a trypsin method. The function and proliferation of cells was analyzed after 7 days of culture. The relative cell growth rate was found to be higher in cellularized porous hydroxyapatite (PHA) than in dense hydroxyapatite. Live-dead staining confirmed viable cells inside the pores of PHA. Increased alkaline phosphatase activity of cells transferred by the cell patch over the trypsin method revealed the significance of cell patch seeding. This novel method of generating tissue constructs by cell patch seeding was successful in cellularizing scaffolds with intact cell function.

  4. Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionRecently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells (NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesenchymal stem cel...

  5. Emerging engineering principles for yield improvement in microbial cell design.

    Science.gov (United States)

    Comba, Santiago; Arabolaza, Ana; Gramajo, Hugo

    2012-01-01

    Metabolic Engineering has undertaken a rapid transformation in the last ten years making real progress towards the production of a wide range of molecules and fine chemicals using a designed cellular host. However, the maximization of product yields through pathway optimization is a constant and central challenge of this field. Traditional methods used to improve the production of target compounds from engineered biosynthetic pathways in non-native hosts include: codon usage optimization, elimination of the accumulation of toxic intermediates or byproducts, enhanced production of rate-limiting enzymes, selection of appropriate promoter and ribosome binding sites, application of directed evolution of enzymes, and chassis re-circuit. Overall, these approaches tend to be specific for each engineering project rather than a systematic practice based on a more generalizable strategy. In this mini-review, we highlight some novel and extensive approaches and tools intended to address the improvement of a target product formation, founded in sophisticated principles such as dynamic control, pathway genes modularization, and flux modeling.

  6. EMERGING ENGINEERING PRINCIPLES FOR YIELD IMPROVEMENT IN MICROBIAL CELL DESIGN

    Directory of Open Access Journals (Sweden)

    Santiago Comba

    2012-10-01

    Full Text Available Metabolic Engineering has undertaken a rapid transformation in the last ten years making real progress towards the production of a wide range of molecules and fine chemicals using a designed cellular host. However, the maximization of product yields through pathway optimization is a constant and central challenge of this field. Traditional methods used to improve the production of target compounds from engineered biosynthetic pathways in non-native hosts include: codon usage optimization, elimination of the accumulation of toxic intermediates or byproducts, enhanced production of rate-limiting enzymes, selection of appropriate promoter and ribosome binding sites, application of directed evolution of enzymes, and chassis re-circuit. Overall, these approaches tend to be specific for each engineering project rather than a systematic practice based on a more generalizable strategy. In this mini-review, we highlight some novel and extensive approaches and tools intended to address the improvement of a target product formation, founded in sophisticated principles such as dynamic control, pathway genes modularization, and flux modeling.

  7. Studying biomolecule localization by engineering bacterial cell wall curvature.

    Directory of Open Access Journals (Sweden)

    Lars D Renner

    Full Text Available In this article we describe two techniques for exploring the relationship between bacterial cell shape and the intracellular organization of proteins. First, we created microchannels in a layer of agarose to reshape live bacterial cells and predictably control their mean cell wall curvature, and quantified the influence of curvature on the localization and distribution of proteins in vivo. Second, we used agarose microchambers to reshape bacteria whose cell wall had been chemically and enzymatically removed. By combining microstructures with different geometries and fluorescence microscopy, we determined the relationship between bacterial shape and the localization for two different membrane-associated proteins: i the cell-shape related protein MreB of Escherichia coli, which is positioned along the long axis of the rod-shaped cell; and ii the negative curvature-sensing cell division protein DivIVA of Bacillus subtilis, which is positioned primarily at cell division sites. Our studies of intracellular organization in live cells of E. coli and B. subtilis demonstrate that MreB is largely excluded from areas of high negative curvature, whereas DivIVA localizes preferentially to regions of high negative curvature. These studies highlight a unique approach for studying the relationship between cell shape and intracellular organization in intact, live bacteria.

  8. One-step fabrication of copper sulfide nanoparticles decorated on graphene sheets as highly stable and efficient counter electrode for CdS-sensitized solar cells

    Science.gov (United States)

    Hessein, Amr; Wang, Feiju; Masai, Hirokazu; Matsuda, Kazunari; Abd El-Moneim, Ahmed

    2016-11-01

    Quantum-dot-sensitized solar cells (QDSSCs) are thin-film photovoltaics and highly promising as next-generation solar cells owing to their high theoretical efficiency, easy fabrication process, and low production cost. However, the practical photoconversion efficiencies (PCEs) of QDSSCs are still far below the theoretically estimated value owing to the lack of an applicable design of the materials and electrodes. In this work, we developed a highly stable and efficient counter electrode (CE) from copper sulfide nanocrystals and reduced graphene oxide (Cu x S@RGO) for QDSSC applications. The Cu x S@RGO electrocatalyst was successfully prepared by a facile one-pot hydrothermal method, then directly applied to a fluorine-doped tin oxide (FTO)-coated glass substrate by the simple drop-casting technique. Owing to the synergistic effect between Cu x S nanocrystals and conductive RGO sheets, the Cu x S@RGO CE showed high electrocatalytic activity for polysulfide electrolyte reduction. A CdS QDSSC based on the Cu x S@RGO CE yielded a high and reproducible PCE of 2.36%, exceeding those of 1.57 and 1.33% obtained with the commonly used Cu2S/brass and Pt CEs, respectively. Moreover, the QDSSC with the Cu x S@RGO CE showed excellent photostability in a light-soaking test without any obvious decay in the photocurrent, whereas the cell based on the Cu2S/brass CE was severely degraded.

  9. Promising Therapeutic Strategies for Mesenchymal Stem Cell-Based Cardiovascular Regeneration: From Cell Priming to Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Seung Taek Ji

    2017-01-01

    Full Text Available The primary cause of death among chronic diseases worldwide is ischemic cardiovascular diseases, such as stroke and myocardial infarction. Recent evidence indicates that adult stem cell therapies involving cardiovascular regeneration represent promising strategies to treat cardiovascular diseases. Owing to their immunomodulatory properties and vascular repair capabilities, mesenchymal stem cells (MSCs are strong candidate therapeutic stem cells for use in cardiovascular regeneration. However, major limitations must be overcome, including their very low survival rate in ischemic lesion. Various attempts have been made to improve the poor survival and longevity of engrafted MSCs. In order to develop novel therapeutic strategies, it is necessary to first identify stem cell modulators for intracellular signal triggering or niche activation. One promising therapeutic strategy is the priming of therapeutic MSCs with stem cell modulators before transplantation. Another is a tissue engineering-based therapeutic strategy involving a cell scaffold, a cell-protein-scaffold architecture made of biomaterials such as ECM or hydrogel, and cell patch- and 3D printing-based tissue engineering. This review focuses on the current clinical applications of MSCs for treating cardiovascular diseases and highlights several therapeutic strategies for promoting the therapeutic efficacy of MSCs in vitro or in vivo from cell priming to tissue engineering strategies, for use in cardiovascular regeneration.

  10. High-density cell systems incorporating polymer microspheres as microenvironmental regulators in engineered cartilage tissues.

    Science.gov (United States)

    Solorio, Loran D; Vieregge, Eran L; Dhami, Chirag D; Alsberg, Eben

    2013-06-01

    To address the significant clinical need for tissue-engineered therapies for the repair and regeneration of articular cartilage, many systems have recently been developed using bioactive polymer microspheres as regulators of the chondrogenic microenvironment within high-density cell cultures. In this review, we highlight various densely cellular systems utilizing polymer microspheres as three-dimensional (3D) structural elements within developing engineered cartilage tissue, carriers for cell expansion and delivery, vehicles for spatiotemporally controlled growth factor delivery, and directors of cell behavior via regulation of cell-biomaterial interactions. The diverse systems described herein represent a shift from the more traditional tissue engineering approach of combining cells and growth factors within a biomaterial scaffold, to the design of modular systems that rely on the assembly of cells and bioactive polymer microspheres as building blocks to guide the creation of articular cartilage. Cell-based assembly of 3D microsphere-incorporated structures represents a promising avenue for the future of tissue engineering.

  11. Establishment and characterization of human engineered cells stably expressing large extracellular matrix proteins.

    Science.gov (United States)

    Kwon, Daekee; Kang, Gwang-Sik; Han, Dong Keun; Park, Kwideok; Kim, Jae-Hwan; Lee, Soo-Hong

    2014-01-01

    Commercially available extracellular matrix (ECM) hydrogel-coated culture plates have been used to study the relationship between the ECM microenvironment and stem cell behavior. However, it is unclear whether ECM-coated dishes mimic the natural ECM microenvironment because the architecture of the ECM is constructed of randomly distributed fibers. The purpose of this study was the production and confirmation of human engineered cell lines stably expressing large ECM proteins such as collagen I/II and fibronectin. First, large (over 10 kb) ECM vectors encoding human collagen I/II and fibronectin were constructed and the circular vectors were linearized. Second, the linear ECM vectors were introduced into immortalized human embryonic kidney cells using various transfection methods. The polyethylenimine and liposome methods showed higher efficiencies than electroporation for transfection of these large vectors. Third, human ECM engineered cells were established by stable integration of the vector into the genomic DNA and resulted in stable overexpression of mRNA and proteins. In summary, human engineered cell lines stably expressing large ECM proteins such as human collagen I/II and fibronectin were successfully prepared, and secretion of the ECM components into the surrounding environment was confirmed by immunocytochemistry. Thus, human ECM engineered cells naturally secreting ECM components could be valuable for studying the relationship between the native ECM microenvironment and stem cell behavior.

  12. Engineered glass seals for solid-oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Surdoval, Wayne; Lara-Curzio, Edgar; Stevenson, Jeffry; Muth, Joseph Thomas; Armstrong, Beth L.; Shyam, Amit; Trejo, Rosa M.; Wang, Yanli; Chou, Yeong Shyung; Shultz, Travis Ray

    2017-02-07

    A seal for a solid oxide fuel cell includes a glass matrix having glass percolation therethrough and having a glass transition temperature below 650.degree. C. A deformable second phase material is dispersed in the glass matrix. The second phase material can be a compliant material. The second phase material can be a crushable material. A solid oxide fuel cell, a precursor for forming a seal for a solid oxide fuel cell, and a method of making a seal for a solid oxide fuel cell are also disclosed.

  13. Preclinical targeting of human T-cell malignancies using CD4-specific chimeric antigen receptor (CAR)-engineered T cells.

    Science.gov (United States)

    Pinz, K; Liu, H; Golightly, M; Jares, A; Lan, F; Zieve, G W; Hagag, N; Schuster, M; Firor, A E; Jiang, X; Ma, Y

    2016-03-01

    Peripheral T-cell lymphomas (PTCLs) are aggressive lymphomas with no effective upfront standard treatment and ineffective options in relapsed disease, resulting in poorer clinical outcomes as compared with B-cell lymphomas. The adoptive transfer of T cells engineered to express chimeric antigen receptors (CARs) is a promising new approach for treatment of hematological malignancies. However, preclinical reports of targeting T-cell lymphoma with CARs are almost non-existent. Here we have designed a CAR, CD4CAR, which redirects the antigen specificity of CD8+ cytotoxic T cells to CD4-expressing cells. CD4CAR T cells derived from human peripheral blood mononuclear cells and cord blood effectively redirected T-cell specificity against CD4+ cells in vitro. CD4CAR T cells efficiently eliminated a CD4+ leukemic cell line and primary CD4+ PTCL patient samples in co-culture assays. Notably, CD4CAR T cells maintained a central memory stem cell-like phenotype (CD8+CD45RO+CD62L+) under standard culture conditions. Furthermore, in aggressive orthotropic T-cell lymphoma models, CD4CAR T cells efficiently suppressed the growth of lymphoma cells while also significantly prolonging mouse survival. Combined, these studies demonstrate that CD4CAR-expressing CD8+ T cells are efficacious in ablating malignant CD4+ populations, with potential use as a bridge to transplant or stand-alone therapy for the treatment of PTCLs.

  14. On the road to synthetic life: the minimal cell and genome-scale engineering.

    Science.gov (United States)

    Juhas, Mario

    2016-01-01

    Synthetic biology employs rational engineering principles to build biological systems from the libraries of standard, well characterized biological parts. Biological systems designed and built by synthetic biologists fulfill a plethora of useful purposes, ranging from better healthcare and energy production to biomanufacturing. Recent advancements in the synthesis, assembly and "booting-up" of synthetic genomes and in low and high-throughput genome engineering have paved the way for engineering on the genome-wide scale. One of the key goals of genome engineering is the construction of minimal genomes consisting solely of essential genes (genes indispensable for survival of living organisms). Besides serving as a toolbox to understand the universal principles of life, the cell encoded by minimal genome could be used to build a stringently controlled "cell factory" with a desired phenotype. This review provides an update on recent advances in the genome-scale engineering with particular emphasis on the engineering of minimal genomes. Furthermore, it presents an ongoing discussion to the scientific community for better suitability of minimal or robust cells for industrial applications.

  15. Cell surface glycan engineering of neural stem cells augments neurotropism and improves recovery in a murine model of multiple sclerosis

    KAUST Repository

    Merzaban, Jasmeen S.

    2015-09-13

    Neural stem cell (NSC)-based therapies offer potential for neural repair in central nervous system (CNS) inflammatory and degenerative disorders. Typically, these conditions present with multifocal CNS lesions making it impractical to inject NSCs locally, thus mandating optimization of vascular delivery of the cells to involved sites. Here, we analyzed NSCs for expression of molecular effectors of cell migration and found that these cells are natively devoid of E-selectin ligands. Using glycosyltransferase-programmed stereosubstitution (GPS), we glycan engineered the cell surface of NSCs ("GPS-NSCs") with resultant enforced expression of the potent E-selectin ligand HCELL (hematopoietic cell E-/L-selectin ligand) and of an E-selectin-binding glycoform of neural cell adhesion molecule ("NCAM-E"). Following intravenous (i.v.) injection, short-term homing studies demonstrated that, compared with buffer-treated (control) NSCs, GPS-NSCs showed greater neurotropism. Administration of GPS-NSC significantly attenuated the clinical course of experimental autoimmune encephalomyelitis (EAE), with markedly decreased inflammation and improved oligodendroglial and axonal integrity, but without evidence of long-term stem cell engraftment. Notably, this effect of NSC is not a universal property of adult stem cells, as administration of GPS-engineered mouse hematopoietic stem/progenitor cells did not improve EAE clinical course. These findings highlight the utility of cell surface glycan engineering to boost stem cell delivery in neuroinflammatory conditions and indicate that, despite the use of a neural tissue-specific progenitor cell population, neural repair in EAE results from endogenous repair and not from direct, NSC-derived cell replacement.

  16. Engineering vascularized bone grafts by integrating a biomimetic periosteum and β-TCP scaffold.

    Science.gov (United States)

    Kang, Yunqing; Ren, Liling; Yang, Yunzhi

    2014-06-25

    Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration.

  17. Concise review: tailoring bioengineered scaffolds for stem cell applications in tissue engineering and regenerative medicine.

    Science.gov (United States)

    Cosson, Steffen; Otte, Ellen A; Hezaveh, Hadi; Cooper-White, Justin J

    2015-02-01

    The potential for the clinical application of stem cells in tissue regeneration is clearly significant. However, this potential has remained largely unrealized owing to the persistent challenges in reproducibly, with tight quality criteria, and expanding and controlling the fate of stem cells in vitro and in vivo. Tissue engineering approaches that rely on reformatting traditional Food and Drug Administration-approved biomedical polymers from fixation devices to porous scaffolds have been shown to lack the complexity required for in vitro stem cell culture models or translation to in vivo applications with high efficacy. This realization has spurred the development of advanced mimetic biomaterials and scaffolds to increasingly enhance our ability to control the cellular microenvironment and, consequently, stem cell fate. New insights into the biology of stem cells are expected to eventuate from these advances in material science, in particular, from synthetic hydrogels that display physicochemical properties reminiscent of the natural cell microenvironment and that can be engineered to display or encode essential biological cues. Merging these advanced biomaterials with high-throughput methods to systematically, and in an unbiased manner, probe the role of scaffold biophysical and biochemical elements on stem cell fate will permit the identification of novel key stem cell behavioral effectors, allow improved in vitro replication of requisite in vivo niche functions, and, ultimately, have a profound impact on our understanding of stem cell biology and unlock their clinical potential in tissue engineering and regenerative medicine.

  18. Ice sheet in peril

    DEFF Research Database (Denmark)

    Hvidberg, Christine Schøtt

    2016-01-01

    Earth's large ice sheets in Greenland and Antarctica are major contributors to sea level change. At present, the Greenland Ice Sheet (see the photo) is losing mass in response to climate warming in Greenland (1), but the present changes also include a long-term response to past climate transitions....... On page 590 of this issue, MacGregor et al. (2) estimate the mean rates of snow accumulation and ice flow of the Greenland Ice Sheet over the past 9000 years based on an ice sheet-wide dated radar stratigraphy (3). They show that the present changes of the Greenland Ice Sheet are partly an ongoing...... response to the last deglaciation. The results help to clarify how sensitive the ice sheet is to climate changes....

  19. Molecular and Nanoscale Engineering of High Efficiency Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jenekhe, Samson A. [Univ. of Washington, Seattle, WA (United States); Ginger, David S. [Univ. of Washington, Seattle, WA (United States); Cao, Guozhong [Univ. of Washington, Seattle, WA (United States)

    2016-01-15

    We combined the synthesis of new polymers and organic-inorganic hybrid materials with new experimental characterization tools to investigate bulk heterojunction (BHJ) polymer solar cells and hybrid organic-inorganic solar cells during the 2007-2010 period (phase I) of this project. We showed that the bulk morphology of polymer/fullerene blend solar cells could be controlled by using either self-assembled polymer semiconductor nanowires or diblock poly(3-alkylthiophenes) as the light-absorbing and hole transport component. We developed new characterization tools in-house, including photoinduced absorption (PIA) spectroscopy, time-resolved electrostatic force microscopy (TR-EFM) and conductive and photoconductive atomic force microscopy (c-AFM and pc-AFM), and used them to investigate charge transfer and recombination dynamics in polymer/fullerene BHJ solar cells, hybrid polymer-nanocrystal (PbSe) devices, and dye-sensitized solar cells (DSSCs); we thus showed in detail how the bulk photovoltaic properties are connected to the nanoscale structure of the BHJ polymer solar cells. We created various oxide semiconductor (ZnO, TiO2) nanostructures by solution processing routes, including hierarchical aggregates and nanorods/nanotubes, and showed that the nanostructured photoanodes resulted in substantially enhanced light-harvesting and charge transport, leading to enhanced power conversion efficiency of dye-sensitized solar cells.

  20. 小鼠胚胎干细胞条件培养液培养的人角膜内皮细胞在脱细胞猪角膜基质上单层细胞片的构建%Formation of cell sheet on acellular porcine corneal stroma with human corneal endothelial cells cocultured by mouse embryonic stem cell conditioned medium

    Institute of Scientific and Technical Information of China (English)

    鹿晓燕; 王智崇

    2016-01-01

    Background Corneal transplantation faces a great challenge because of the shortage of corneal donors and difficulty of human corneal endothelial cells (HCECs) regeneration in vitro.So the study on tissue engineering cornea is still a main topic.Previous research showed that mouse embryonic stem cell conditioned medium (ESC-CM) improved the proliferative capacity of HCECs in vitro,and acellular porcine corneal stroma (APCS) was a good saffold material.However,whether HECEs cultured by mouse ESC-CM can form cell sheet in vitro were rarely studied.Objective This study was to investigate the potential that HCECs cultured by mouse ESC-CM form a monolayer cell sheet.Methods The supernatant of ESC-CM was collected after mouse ES-E14 cells were cultured,and the cultured medium was centrifuged and mixed with 75% human corneal endothelium medium (CEM)at a proportion of 1 ∶ 3 to prepare the 25% ESC-CM system.Primary cultures of HCECs were established from explants of corneal limbal with Descemet's membrane,and the cells were identified by using reverse-transcription PCR to determine the expressions of collagen Ⅷ (Col Ⅷ) mRNA and neuron-specific enolase (NSE) mRNA in the cells.APCS was prepared by decellularization with phospholipase A2 and bicarbonate solution,and the second generation of HCECs were inoculated on the sterilized APCS at a 800/mm2 density.The morphology of the cells was observed by hematoxylin-eosin staining under the phase-contrast microscope.The expressions of zona occludens protein-1 (ZO-1)and Na+-K+-ATPase in the cell sheet were detected by immunofluorescence staining.Results The second generation of HCECs cultured with 25% ESC-CM in vitro showed the hexagon in shape with positive expressions for Col Ⅷ mRNA and NSE mRNA.Decellularization APCS was transparent,and no corneal cells were seen,the structures of corneal collagenous fibres were regular.HCECs attached closely to APCS and formed monolayer sheet 7 days after culture on the APCS with the

  1. Engineering controlled mammalian type O-Glycosylation in plant cells

    DEFF Research Database (Denmark)

    Yang, Zhang; Drew, Damian Paul; Jørgensen, Bodil

    2011-01-01

    Human mucins are large heavily O-glycosylated glycoproteins (>200 kDa), which account for the majority of proteins in mucus layers that e.g. hydrate, lubricate and protect cells from proteases as well as from pathogens. O-linked mucin glycans are truncated in many cancers, yielding truncated cancer...... specific glyco-peptide epitopes, such as the Tn epitope (GalNAc sugar attached to either Serine or Threonine), which are antigenic to the immune system. In the present study, we have identified plant cells as the only eukaryotic cells without mammalian type O-glycosylation or competing (for sites) O...

  2. Tissue engineering bioreactor systems for applying physical and electrical stimulations to cells.

    Science.gov (United States)

    Jin, GyuHyun; Yang, Gi-Hoon; Kim, GeunHyung

    2015-05-01

    Bioreactor systems in tissue engineering applications provide various types of stimulation to mimic the tissues in vitro and in vivo. Various bioreactors have been designed to induce high cellular activities, including initial cell attachment, cell growth, and differentiation. Although cell-stimulation processes exert mostly positive effects on cellular responses, in some cases such stimulation can also have a negative effect on cultured cells. In this review, we discuss various types of bioreactor and the positive and negative effects of stimulation (physical, chemical, and electrical) on various cultured cell types.

  3. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ino, Hiroichi; Ueta, Shouhei; Suzuki, Hiroshi; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tobita, Tsutomu [Nuclear Engineering Company, Ltd., Tokai, Ibaraki (Japan)

    2002-01-01

    This report summarizes design requirements and design results for shields, ventilation system and fuel handling devices for the high temperature irradiation materials inspection cells (spent fuel inspection cells). These cells are small cells to carry out few post-irradiation examinations of spent fuels, specimen, etc., which are irradiated in the High Temperature Engineering Test Reactor, since the cells should be built in limited space in the HTTR reactor building, the cells are designed considering relationship between the cells and the reactor building to utilize the limited space effectively. The cells consist of three partitioned hot cells with wall for neutron and gamma-ray shields, ventilation system including filtering units and fuel handling devices. The post-irradiation examinations of the fuels and materials are planed by using the cells and the Hot Laboratory of the Japan Materials Testing Reactor to establish the technology basis on high temperature gas-cooled reactors (HTGRs). In future, irradiation tests and post-irradiation examinations will be carried out with the cells to upgrade present HTGR technologies and to make the innovative basic research on high-temperature engineering. (author)

  4. High Sensitive and Selective Sensing of Hydrogen Peroxide Released from Pheochromocytoma Cells Based on Pt-Au Bimetallic Nanoparticles Electrodeposited on Reduced Graphene Sheets

    Directory of Open Access Journals (Sweden)

    Guangxia Yu

    2015-01-01

    Full Text Available In this study, a high sensitive and selective hydrogen peroxide (H2O2 sensor was successfully constructed with Pt-Au bimetallic nanoparticles (Pt-Au NPs/reduced graphene sheets (rGSs hybrid films. Various molar ratios of Au to Pt and different electrodeposition conditions were evaluated to control the morphology and electrocatalytic activity of the Pt-Au bimetallic nanoparticles. Upon optimal conditions, wide linear ranges from 1 µM to 1.78 mM and 1.78 mM to 16.8 mM were obtained, with a detection limit as low as 0.31 µM. Besides, due to the synergetic effects of the bimetallic NPs and rGSs, the amperometric H2O2 sensor could operate at a low potential of 0 V. Under this potential, not only common anodic interferences induced from ascorbic acid, uric acid and dopamine, but also the cathodic interference induced from endogenous O2 could be effectively avoided. Furthermore, with rat pheochromocytoma cells (PC 12 as model, the proposed sensor had been successfully used in the detection of H2O2 released from the cancer cells. This method with wide linear ranges and excellent selectivity can provide a promising alternative for H2O2 monitoring in vivo in the fields of physiology, pathology and diagnosis.

  5. Cell surface engineering of industrial microorganisms for biorefining applications.

    Science.gov (United States)

    Tanaka, Tsutomu; Kondo, Akihiko

    2015-11-15

    In order to decrease carbon emissions and negative environmental impacts of various pollutants, biofuel/biochemical production should be promoted for replacing fossil-based industrial processes. Utilization of abundant lignocellulosic biomass as a feedstock has recently become an attractive option. In this review, we focus on recent efforts of cell surface display using industrial microorganisms such as Escherichia coli and yeast. Cell surface display is used primarily for endowing cellulolytic activity on the host cells, and enables direct fermentation to generate useful fuels and chemicals from lignocellulosic biomass. Cell surface display systems are systematically summarized, and the drawbacks/perspectives as well as successful application of surface display for industrial biotechnology are discussed.

  6. The Neurovascular Properties of Dental Stem Cells and Their Importance in Dental Tissue Engineering

    Science.gov (United States)

    Ratajczak, Jessica; Bronckaers, Annelies; Dillen, Yörg; Gervois, Pascal; Vangansewinkel, Tim; Driesen, Ronald B.; Wolfs, Esther; Lambrichts, Ivo

    2016-01-01

    Within the field of tissue engineering, natural tissues are reconstructed by combining growth factors, stem cells, and different biomaterials to serve as a scaffold for novel tissue growth. As adequate vascularization and innervation are essential components for the viability of regenerated tissues, there is a high need for easily accessible stem cells that are capable of supporting these functions. Within the human tooth and its surrounding tissues, different stem cell populations can be distinguished, such as dental pulp stem cells, stem cells from human deciduous teeth, stem cells from the apical papilla, dental follicle stem cells, and periodontal ligament stem cells. Given their straightforward and relatively easy isolation from extracted third molars, dental stem cells (DSCs) have become an attractive source of mesenchymal-like stem cells. Over the past decade, there have been numerous studies supporting the angiogenic, neuroprotective, and neurotrophic effects of the DSC secretome. Together with their ability to differentiate into endothelial cells and neural cell types, this makes DSCs suitable candidates for dental tissue engineering and nerve injury repair. PMID:27688777

  7. Electron Acceptor Materials Engineering in Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Liu, Huan

    2011-07-15

    Lead sulfide colloidal quantum dot (CQD) solar cells with a solar power conversion efficiency of 5.6% are reported. The result is achieved through careful optimization of the titanium dioxide electrode that serves as the electron acceptor. Metal-ion-doped sol-gel-derived titanium dioxide electrodes produce a tunable-bandedge, well-passivated materials platform for CQD solar cell optimization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Hair follicle: a novel source of multipotent stem cells for tissue engineering and regenerative medicine.

    Science.gov (United States)

    Mistriotis, Panagiotis; Andreadis, Stelios T

    2013-08-01

    The adult body harbors powerful reservoirs of stem cells that enable tissue regeneration under homeostatic conditions or in response to disease or injury. The hair follicle (HF) is a readily accessible mini organ within the skin and contains stem cells from diverse developmental origins that were shown to have surprisingly broad differentiation potential. In this review, we discuss the biology of the HF with particular emphasis on the various stem cell populations residing within the tissue. We summarize the existing knowledge on putative HF stem cell markers, the differentiation potential, and technologies to isolate and expand distinct stem cell populations. We also discuss the potential of HF stem cells for drug and gene delivery, tissue engineering, and regenerative medicine. We propose that the abundance of stem cells with broad differentiation potential and the ease of accessibility makes the HF an ideal source of stem cells for gene and cell therapies.

  9. The use of hTERT-immortalized cells in tissue engineering

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Abdallah, Basem; Yu, Zentao

    2004-01-01

    The use of human telomerase reverse transcriptase (hTERT)-immortalized cells in tissue engineering protocols is a potentially important application of telomere biology. Several human cell types have been created that overexpress the hTERT gene with enhanced telomerase activity, extended life span...... and maintained or even improved functional activities. Furthermore, some studies have employed the telomerized cells in tissue engineering protocols with very good results. However, high telomerase activity allows extensive cell proliferation that may be associated with genomic instability and risk for cell...... transformation. Thus, safety issues should be studied carefully before using the telomerized tissues in the clinic. Alternatively, the development of conditional or intermittent telomerase activation protocols is needed....

  10. Genetic engineering of mesenchymal stem cells and its application in human disease therapy.

    Science.gov (United States)

    Hodgkinson, Conrad P; Gomez, José A; Mirotsou, Maria; Dzau, Victor J

    2010-11-01

    The use of stem cells for tissue regeneration and repair is advancing both at the bench and bedside. Stem cells isolated from bone marrow are currently being tested for their therapeutic potential in a variety of clinical conditions including cardiovascular injury, kidney failure, cancer, and neurological and bone disorders. Despite the advantages, stem cell therapy is still limited by low survival, engraftment, and homing to damage area as well as inefficiencies in differentiating into fully functional tissues. Genetic engineering of mesenchymal stem cells is being explored as a means to circumvent some of these problems. This review presents the current understanding of the use of genetically engineered mesenchymal stem cells in human disease therapy with emphasis on genetic modifications aimed to improve survival, homing, angiogenesis, and heart function after myocardial infarction. Advancements in other disease areas are also discussed.

  11. Reverse engineering the mechanical and molecular pathways in stem cell morphogenesis.

    Science.gov (United States)

    Lu, Kai; Gordon, Richard; Cao, Tong

    2015-03-01

    The formation of relevant biological structures poses a challenge for regenerative medicine. During embryogenesis, embryonic cells differentiate into somatic tissues and undergo morphogenesis to produce three-dimensional organs. Using stem cells, we can recapitulate this process and create biological constructs for therapeutic transplantation. However, imperfect imitation of nature sometimes results in in vitro artifacts that fail to recapitulate the function of native organs. It has been hypothesized that developing cells may self-organize into tissue-specific structures given a correct in vitro environment. This proposition is supported by the generation of neo-organoids from stem cells. We suggest that morphogenesis may be reverse engineered to uncover its interacting mechanical pathway and molecular circuitry. By harnessing the latent architecture of stem cells, novel tissue-engineering strategies may be conceptualized for generating self-organizing transplants.

  12. Tissue engineering and cell-based therapy toward integrated strategy with artificial organs.

    Science.gov (United States)

    Gojo, Satoshi; Toyoda, Masashi; Umezawa, Akihiro

    2011-09-01

    Research in order that artificial organs can supplement or completely replace the functions of impaired or damaged tissues and internal organs has been underway for many years. The recent clinical development of implantable left ventricular assist devices has revolutionized the treatment of patients with heart failure. The emerging field of regenerative medicine, which uses human cells and tissues to regenerate internal organs, is now advancing from basic and clinical research to clinical application. In this review, we focus on the novel biomaterials, i.e., fusion protein, and approaches such as three-dimensional and whole-organ tissue engineering. We also compare induced pluripotent stem cells, directly reprogrammed cardiomyocytes, and somatic stem cells for cell source of future cell-based therapy. Integrated strategy of artificial organ and tissue engineering/regenerative medicine should give rise to a new era of medical treatment to organ failure.

  13. An Ultra-thin Amniotic Membrane as Carrier in Corneal Epithelium Tissue-Engineering.

    Science.gov (United States)

    Zhang, Liying; Zou, Dulei; Li, Sanming; Wang, Junqi; Qu, Yangluowa; Ou, Shangkun; Jia, Changkai; Li, Juan; He, Hui; Liu, Tingting; Yang, Jie; Chen, Yongxiong; Liu, Zuguo; Li, Wei

    2016-02-15

    Amniotic membranes (AMs) are widely used as a corneal epithelial tissue carrier in reconstruction surgery. However, the engineered tissue transparency is low due to the translucent thick underlying AM stroma. To overcome this drawback, we developed an ultra-thin AM (UAM) by using collagenase IV to strip away from the epithelial denuded AM (DAM) some of the stroma. By thinning the stroma to about 30 μm, its moist and dry forms were rendered acellular, optically clear and its collagen framework became compacted and inerratic. Engineered rabbit corneal epithelial cell (RCEC) sheets generated through expansion of limbal epithelial cells on UAM were more transparent and thicker than those expanded on DAM. Moreover, ΔNp63 and ABCG2 gene expression was greater in tissue engineered cell sheets expanded on UAM than on DAM. Furthermore, 2 weeks after surgery, the cornea grafted with UAM based cell sheets showed higher transparency and more stratified epithelium than the cornea grafted with DAM based cell sheets. Taken together, tissue engineered corneal epithelium generated on UAM has a preferable outcome because the transplanted tissue is more transparent and better resembles the phenotype of the native tissue than that obtained by using DAM for this procedure. UAM preserves compact layer of the amniotic membrane and maybe an ideal substrate for corneal epithelial tissue engineering.

  14. Concise Review : Engineering Myocardial Tissue: The Convergence of Stem Cells Biology and Tissue Engineering Technology

    NARCIS (Netherlands)

    Buikema, Jan Willem; Van der Meer, Peter; Sluijter, Joost P. G.; Domian, Ibrahim J.

    2013-01-01

    Advanced heart failure represents a leading public health problem in the developed world. The clinical syndrome results from the loss of viable and/or fully functional myocardial tissue. Designing new approaches to augment the number of functioning human cardiac muscle cells in the failing heart ser

  15. Electrical detachment of cells for engineering capillary-like structures in a photocrosslinkable hydrogel.

    Science.gov (United States)

    Osaki, Tatsuya; Kakegawa, Takahiro; Suzuki, Hiroaki; Fukuda, Junji

    2011-01-01

    A major challenge in tissue engineering is the fabrication of vascular networks capable of delivering oxygen and nutrients throughout tissue constructs. Because cells located more than a few hundred micrometers away from the nearest capillaries are susceptible to oxygen shortages, it is crucial to develop microscale technologies for engineering a vascular structure in three-dimensionally thick tissues. This study describes an electrochemical approach for fabricating capillary-like structures precisely aligned within micrometer distances, the internal surfaces of which are covered with vascular endothelial cells in a photocrosslinkable hydrogel.

  16. Nanophase Engineering of Organic Semiconductor-based Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Ming [ORNL; Keum, Jong Kahk [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL

    2015-01-01

    Organic photovoltaics are promising low-cost, easily-processable energy sources of the future, and are the subject of current academic and industrial interest. In order to achieve the envisioned device efficiencies to surpass commercialization target values, several challenges must be met: (1) to design and synthesize conjugated molecules with low optical bandgaps and optimized electronic energy levels, (2) optimization the morphology of donor/acceptor interpenetrating networks by controlling nanoscale phase separation and self-assembly, and (3) precise tuning of the active layer/electrode interfaces and donor/acceptor interfaces for optimized charge transfer. Here, we focus on recent advances in: (i) synthetic strategies for low-bandgap conjugated polymers and novel fullerene acceptors, (ii) processing to tune film morphologies by solvent annealing, thermal annealing, and the use of solvent additives and compatibilizers, and (iii) engineering of active layer/electrode interfaces and donor/acceptor interfaces with self-assembled monolayer dipoles.

  17. Metabolically engineered cells for the production of pinosylvin

    DEFF Research Database (Denmark)

    2008-01-01

    A genetically engineered micro-organism having an operative metabolic pathway producing cinnamoyl-CoA and producing pinosylvin therefrom by the action of a stilbene synthase is used for pinosylvin production. Said cinnamic acid may be formed from L-phenylalanine by a L-phenylalanine ammonia lyase...... (PAL) which is one accepting phenylalanine as a substrate and producing cinammic acid therefrom, preferably such that if the PAL also accepts tyrosine as a substrate and forms coumaric acid therefrom, the ratio Km(phenylalanine)/Km(tyrosine) for said PAL is less than 1:1 and if said micro......-organism produces a cinammate-4- hydroxylase enzyme (C4H), the ratio Kcat(PAL)/Kcat(C4H) is at least 2:1....

  18. Membrane transporter engineering in industrial biotechnology and whole cell biocatalysis.

    Science.gov (United States)

    Kell, Douglas B; Swainston, Neil; Pir, Pınar; Oliver, Stephen G

    2015-04-01

    Because they mainly do not involve chemical changes, membrane transporters have been a Cinderella subject in the biotechnology of small molecule production, but this is a serious oversight. Influx transporters contribute significantly to the flux towards product, and efflux transporters ensure the accumulation of product in the much greater extracellular space of fermentors. Programmes for improving biotechnological processes might therefore give greater consideration to transporters than may have been commonplace. Strategies for identifying important transporters include expression profiling, genome-wide knockout studies, stress-based selection, and the use of inhibitors. In addition, modern methods of directed evolution and synthetic biology, especially those effecting changes in energy coupling, offer huge opportunities for increasing the flux towards extracellular product formation by transporter engineering.

  19. Proteomics in Cell Culture: From Genomics to Combined ‘Omics for Cell Line Engineering and Bioprocess Development

    DEFF Research Database (Denmark)

    Heffner, Kelley; Kaas, Christian Schrøder; Kumar, Amit;

    2015-01-01

    The genetic sequencing of Chinese hamster ovary cells has initiated a systems biology era for biotechnology applications. In addition to genomics, critical omics data sets also include proteomics, transcriptomics and metabolomics. Recently, the use of proteomics in cell lines for recombinant...... in media development and cell line engineering to improve growth or productivity, delay the onset of apoptosis, or utilize nutrients efficiently. Mass-spectrometry based and other proteomics methods can provide for the detection of thousands of proteins from cell culture and bioinformatics analysis serves...

  20. Advances of mesenchymal stem cells derived from bone marrow and dental tissue in craniofacial tissue engineering.

    Science.gov (United States)

    Yang, Maobin; Zhang, Hongming; Gangolli, Riddhi

    2014-05-01

    Bone and dental tissues in craniofacial region work as an important aesthetic and functional unit. Reconstruction of craniofacial tissue defects is highly expected to ensure patients to maintain good quality of life. Tissue engineering and regenerative medicine have been developed in the last two decades, and been advanced with the stem cell technology. Bone marrow derived mesenchymal stem cells are one of the most extensively studied post-natal stem cell population, and are widely utilized in cell-based therapy. Dental tissue derived mesenchymal stem cells are a relatively new stem cell population that isolated from various dental tissues. These cells can undergo multilineage differentiation including osteogenic and odontogenic differentiation, thus provide an alternative source of mesenchymal stem cells for tissue engineering. In this review, we discuss the important issues in mesenchymal stem cell biology including the origin and functions of mesenchymal stem cells, compare the properties of these two types of mesenchymal cells, update recent basic research and clinic applications in this field, and address important future challenges.

  1. Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    Yan JIN; Liu-Yu BAO; Yi-Jing WANG; Hui-Xia HE

    2005-01-01

    @@ 1 Introduction Recently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells(NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesenchymal stem cells(EMSC) and to demonstrate that EMSCs have the ability of plasticity both in vivo and in vitro. The further interesting was to evaluate the role of EMSC in producing of a tissue engineering tooth together with odontogenic epithelium.

  2. Recent Progress on Systems and Synthetic Biology Approaches to Engineer Fungi As Microbial Cell Factories.

    Science.gov (United States)

    Amores, Gerardo Ruiz; Guazzaroni, María-Eugenia; Arruda, Letícia Magalhães; Silva-Rocha, Rafael

    2016-04-01

    Filamentous fungi are remarkable organisms naturally specialized in deconstructing plant biomass and this feature has a tremendous potential for biofuel production from renewable sources. The past decades have been marked by a remarkable progress in the genetic engineering of fungi to generate industry-compatible strains needed for some biotech applications. In this sense, progress in this field has been marked by the utilization of high-throughput techniques to gain deep understanding of the molecular machinery controlling the physiology of these organisms, starting thus the Systems Biology era of fungi. Additionally, genetic engineering has been extensively applied to modify wellcharacterized promoters in order to construct new expression systems with enhanced performance under the conditions of interest. In this review, we discuss some aspects related to significant progress in the understating and engineering of fungi for biotechnological applications, with special focus on the construction of synthetic promoters and circuits in organisms relevant for industry. Different engineering approaches are shown, and their potential and limitations for the construction of complex synthetic circuits in these organisms are examined. Finally, we discuss the impact of engineered promoter architecture in the single-cell behavior of the system, an often-neglected relationship with a tremendous impact in the final performance of the process of interest. We expect to provide here some new directions to drive future research directed to the construction of high-performance, engineered fungal strains working as microbial cell factories.

  3. Cartilage tissue engineering: From biomaterials and stem cells to osteoarthritis treatments.

    Science.gov (United States)

    Vinatier, C; Guicheux, J

    2016-06-01

    Articular cartilage is a non-vascularized and poorly cellularized connective tissue that is frequently damaged as a result of trauma and degenerative joint diseases such as osteoarthrtis. Because of the absence of vascularization, articular cartilage has low capacity for spontaneous repair. Today, and despite a large number of preclinical data, no therapy capable of restoring the healthy structure and function of damaged articular cartilage is clinically available. Tissue-engineering strategies involving the combination of cells, scaffolding biomaterials and bioactive agents have been of interest notably for the repair of damaged articular cartilage. During the last 30 years, cartilage tissue engineering has evolved from the treatment of focal lesions of articular cartilage to the development of strategies targeting the osteoarthritis process. In this review, we focus on the different aspects of tissue engineering applied to cartilage engineering. We first discuss cells, biomaterials and biological or environmental factors instrumental to the development of cartilage tissue engineering, then review the potential development of cartilage engineering strategies targeting new emerging pathogenic mechanisms of osteoarthritis.

  4. Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue

    Science.gov (United States)

    Armstrong, James P. K.; Shakur, Rameen; Horne, Joseph P.; Dickinson, Sally C.; Armstrong, Craig T.; Lau, Katherine; Kadiwala, Juned; Lowe, Robert; Seddon, Annela; Mann, Stephen; Anderson, J. L. Ross; Perriman, Adam W.; Hollander, Anthony P.

    2015-06-01

    Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymer-surfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymer-surfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.

  5. Photovoltaics. Interface engineering of highly efficient perovskite solar cells.

    Science.gov (United States)

    Zhou, Huanping; Chen, Qi; Li, Gang; Luo, Song; Song, Tze-bing; Duan, Hsin-Sheng; Hong, Ziruo; You, Jingbi; Liu, Yongsheng; Yang, Yang

    2014-08-01

    Advancing perovskite solar cell technologies toward their theoretical power conversion efficiency (PCE) requires delicate control over the carrier dynamics throughout the entire device. By controlling the formation of the perovskite layer and careful choices of other materials, we suppressed carrier recombination in the absorber, facilitated carrier injection into the carrier transport layers, and maintained good carrier extraction at the electrodes. When measured via reverse bias scan, cell PCE is typically boosted to 16.6% on average, with the highest efficiency of ~19.3% in a planar geometry without antireflective coating. The fabrication of our perovskite solar cells was conducted in air and from solution at low temperatures, which should simplify manufacturing of large-area perovskite devices that are inexpensive and perform at high levels.

  6. Engineering Cell Fate for Tissue Regeneration by In Vivo Transdifferentiation.

    Science.gov (United States)

    de Lázaro, I; Kostarelos, K

    2016-02-01

    Changes in cell identity occur in adult mammalian organisms but are rare and often linked to disease. Research in the last few decades has thrown light on how to manipulate cell fate, but the conversion of a particular cell type into another within a living organism (also termed in vivo transdifferentiation) has only been recently achieved in a limited number of tissues. Although the therapeutic promise of this strategy for tissue regeneration and repair is exciting, important efficacy and safety concerns will need to be addressed before it becomes a reality in the clinical practice. Here, we review the most relevant in vivo transdifferentiation studies in adult mammalian animal models, offering a critical assessment of this potentially powerful strategy for regenerative medicine.

  7. Bandgap Engineering in High-Efficiency Multijunction Concentrator Cells

    Energy Technology Data Exchange (ETDEWEB)

    King, R. R.; Sherif, R. A.; Kinsey, G. S.; Kurtz, S.; Fetzer, C. M.; Edmondson, K. M.; Law, D. C.; Cotal, H. L.; Krut, D. D.; Ermer, J. H.; Karam, N. H.

    2005-08-01

    This paper discusses semiconductor device research paths under investigation with the aim of reaching the milestone efficiency of 40%. A cost analysis shows that achieving very high cell efficiencies is crucial for the realization of cost-effective photovoltaics, because of the strongly leveraging effect of efficiency on module packaging and balance-of systems costs. Lattice-matched (LM) GaInP/ GaInAs/ Ge 3-junction cells have achieved the highest independently confirmed efficiency at 175 suns, 25?C, of 37.3% under the standard AM1.5D, low-AOD terrestrial spectrum. Lattice-mismatched, or metamorphic (MM), materials offer still higher potential efficiencies, if the crystal quality can be maintained. Theoretical efficiencies well over 50% are possible for a MM GaInP/ 1.17-eV GaInAs/ Ge 3-junction cell limited by radiative recombination at 500 suns. The bandgap - open circuit voltage offset, (Eg/q) - Voc, is used as a valuable theoretical and experimental tool to characterize multijunction cells with subcell bandgaps ranging from 0.7 to 2.1 eV. Experimental results are presented for prototype 6-junction cells employing an active {approx}1.1-eV dilute nitride GaInNAs subcell, with active-area efficiency greater than 23% and over 5.3 V open-circuit voltage under the 1-sun AM0 space spectrum. Such cell designs have theoretical efficiencies under the terrestrial spectrum at 500 suns concentration exceeding 55% efficiency, even for lattice-matched designs.

  8. Acceleration of cell factories engineering using CRISPR-based technologies

    DEFF Research Database (Denmark)

    Ronda, Carlotta

    potentially be standardized in an automatable platform and, in the future be integrated with metabolic modeling tools. In particularly it describes the technologies developed in the three widely used organisms: E. coli, S. cerevisiae and CHO mammalian cells using the recent breakthrough CRISPR/ Cas9 system....... These include CRMAGE, a MAGE improved recombineering platform using CRISPR negative selection, CrEdit, a system for multi-loci marker-free simultaneous gene and pathway integrations and CRISPy a platform to accelerate genome editing in CHO cells....

  9. Engineering Synthetic Gene Circuits in Living Cells with CRISPR Technology.

    Science.gov (United States)

    Jusiak, Barbara; Cleto, Sara; Perez-Piñera, Pablo; Lu, Timothy K

    2016-07-01

    One of the goals of synthetic biology is to build regulatory circuits that control cell behavior, for both basic research purposes and biomedical applications. The ability to build transcriptional regulatory devices depends on the availability of programmable, sequence-specific, and effective synthetic transcription factors (TFs). The prokaryotic clustered regularly interspaced short palindromic repeat (CRISPR) system, recently harnessed for transcriptional regulation in various heterologous host cells, offers unprecedented ease in designing synthetic TFs. We review how CRISPR can be used to build synthetic gene circuits and discuss recent advances in CRISPR-mediated gene regulation that offer the potential to build increasingly complex, programmable, and efficient gene circuits in the future.

  10. Contamination of genetically engineered Chinese hamster ovary cells.

    Science.gov (United States)

    Burstyn, D G

    1996-01-01

    In late 1988, during production of a recombinant protein for phase I clinical trials, a failure of the cell culture production system occurred due to contamination of the cells by an orbivirus [1]. The incident occurred at Bioferon GmbH & Co, Laupheim, Germany, a joint venture of Biogen, Inc., Cambridge, MA, and Dr. Renstschler Arzneimittel GmbH & Co (Bioferon is currently a wholly owned subsidiary of Rentschler and is now known as Dr. Rentschler Biotechnologie GmbH). The investigation into, and the subsequent response to, the infection can be divided into three stages: Stage I, Investigation and initial response; Stage II, Secondary response; and Stage III: Continuing response.

  11. Tissue engineering of ligaments : A comparison of bone marrow stromal cells, anterior cruciate ligament, and skin fibroblasts as cell source

    NARCIS (Netherlands)

    Van Eijk, F; Riesle, J; Willems, WJ; Van Blitterswijk, CA; Verbout, AJ; Dhert, WJA

    2004-01-01

    Anterior cruciate ligament (ACL) reconstruction surgery still has important problems to overcome, such as "donor site morbidity" and the limited choice of grafts in revision surgery. Tissue engineering of ligaments may provide a solution for these problems. Little is known about the optimal cell sou

  12. Regional effects of enzymatic digestion on knee meniscus cell yield and phenotype for tissue engineering.

    Science.gov (United States)

    Sanchez-Adams, Johannah; Athanasiou, Kyriacos A

    2012-03-01

    An abundant cell source is the cornerstone of most tissue engineering strategies, but extracting cells from the knee meniscus is hindered by its dense fibrocartilaginous matrix. Identifying a method to efficiently isolate meniscus cells is important, as it can reduce the cost and effort required to perform meniscus engineering research. In this study, six enzymatic digestion regimens used for cartilaginous cell isolation were used to isolate cells from the outer, middle, and inner regions of the bovine knee meniscus. Each regimen in each region was assessed in terms of cell yield, impact on cell phenotype, and cytotoxicity. All digestion regimens caused an overall upregulation of cartilage-specific genes Sox9, collagen type I (Col 1), collagen type II (Col 2), cartilage oligomeric matrix protein, and aggrecan (AGC) in cells from all meniscus regions, but was highest for cells isolated using 1075 U/mL of collagenase for 3 h (high collagenase). In response to isolation, outer meniscus cells showed highest upregulation of Sox9 and Col 1 genes, whereas greatest upregulation for middle meniscus cells was seen in Col 1 expression, and Col 2 expression for inner cells. Cell yield was highest in all regions when subjected to 45 min of 61 U/mL pronase followed by 3 h of 1075 U/mL collagenase (pronase/collagenase [P/C]) digestion regimen (outer: 6.57±0.37, middle: 12.77±1.41, inner: 22.17±1.47×10(6) cells/g tissue). The second highest cell yield was achieved using the low collagenase (LC) digestion regimen that applied 433 U/mL of collagenase for 18 h (outer: 1.95±0.54, middle: 3.3±4.4, inner: 6.06±2.44×10(6) cells/g tissue). Cytotoxicity analysis showed higher cell death in the LC group compared with the P/C group. Self-assembled constructs formed from LC-isolated cells were less dense than constructs formed from P/C-isolated cells, and P/C constructs showed higher glycosaminoglycan content and compressive moduli than LC constructs. All isolation methods tested

  13. Engineered neural tissue with aligned, differentiated adipose-derived stem cells promotes peripheral nerve regeneration across a critical sized defect in rat sciatic nerve.

    Science.gov (United States)

    Georgiou, Melanie; Golding, Jon P; Loughlin, Alison J; Kingham, Paul J; Phillips, James B

    2015-01-01

    Adipose-derived stem cells were isolated from rats and differentiated to a Schwann cell-like phenotype in vitro. The differentiated cells (dADSCs) underwent self-alignment in a tethered type-1 collagen gel, followed by stabilisation to generate engineered neural tissue (EngNT-dADSC). The pro-regenerative phenotype of dADSCs was enhanced by this process, and the columns of aligned dADSCs in the aligned collagen matrix supported and guided neurite extension in vitro. EngNT-dADSC sheets were rolled to form peripheral nerve repair constructs that were implanted within NeuraWrap conduits to bridge a 15 mm gap in rat sciatic nerve. After 8 weeks regeneration was assessed using immunofluorescence imaging and transmission electron microscopy and compared to empty conduit and nerve graft controls. The proportion of axons detected in the distal stump was 3.5 fold greater in constructs containing EngNT-dADSC than empty tube controls. Our novel combination of technologies that can organise autologous therapeutic cells within an artificial tissue construct provides a promising new cellular biomaterial for peripheral nerve repair.

  14. Thermoforming of foam sheet

    NARCIS (Netherlands)

    Akkerman, Remko; Pronk, Ruud M.

    1997-01-01

    Thermoforming is a widely used process for the manufacture of foam sheet products. Polystyrene foam food trays for instance can be produced by first heating the thermoplastic foam sheet, causing the gas contained to build up pressure and expand, after which a vacuum pressure can be applied to draw t

  15. Paper-based bioactive scaffolds for stem cell-mediated bone tissue engineering.

    Science.gov (United States)

    Park, Hyun-Ji; Yu, Seung Jung; Yang, Kisuk; Jin, Yoonhee; Cho, Ann-Na; Kim, Jin; Lee, Bora; Yang, Hee Seok; Im, Sung Gap; Cho, Seung-Woo

    2014-12-01

    Bioactive, functional scaffolds are required to improve the regenerative potential of stem cells for tissue reconstruction and functional recovery of damaged tissues. Here, we report a paper-based bioactive scaffold platform for stem cell culture and transplantation for bone reconstruction. The paper scaffolds are surface-engineered by an initiated chemical vapor deposition process for serial coating of a water-repellent and cell-adhesive polymer film, which ensures the long-term stability in cell culture medium and induces efficient cell attachment. The prepared paper scaffolds are compatible with general stem cell culture and manipulation techniques. An optimal paper type is found to provide structural, physical, and mechanical cues to enhance the osteogenic differentiation of human adipose-derived stem cells (hADSCs). A bioactive paper scaffold significantly enhances in vivo bone regeneration of hADSCs in a critical-sized calvarial bone defect. Stacking the paper scaffolds with osteogenically differentiated hADSCs and human endothelial cells resulted in vascularized bone formation in vivo. Our study suggests that paper possesses great potential as a bioactive, functional, and cost-effective scaffold platform for stem cell-mediated bone tissue engineering. To the best of our knowledge, this is the first study reporting the feasibility of a paper material for stem cell application to repair tissue defects.

  16. Full-thickness tissue engineered skin constructed with autogenic bone marrow mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To explore the feasibility of repairing clinical cutaneous deficiency, autogenic bone marrow mesen-chymal stem cells (BMSCs) were isolated and differentiated into epidermal cells and fibroblasts in vitro supplemented with different inducing factors and biomaterials to construct functional tissue- engineered skin. The results showed that after 72 h induction, BMSCs displayed morphologic changes such as typical epidermal cell arrangement, from spindle shape to round or oval; tonofibrils, melano-somes and keratohyaline granules were observed under a transmission electronic microscope. The differentiated cells expressed epidermal stem cell surface marker CK19 (59.66% ± 4.2%) and epidermal cells differentiation marker CK10. In addition, the induced epidermal cells acquired the anti-radiation capacity featured by lowered apoptosis following exposure to UVB. On the other hand, the collagen microfibrils deposition was noticed under a transmission electronic microscope after differentiating into dermis fibroblasts; RT-PCR identified collagen type I mRNA expression in differentiated cells; radioimmunoassay detected the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8) (up to 115.06 pg/mL and 0.84 ng/mL, respectively). Further in vivo implanting BMSCs with scaffold material short-ened skin wound repair significantly. In one word, autogenic BMSCs have the potential to differentiate into epidermal cells and fibroblasts in vitro, and show clinical feasibility acting as epidermis-like and dermis-like seed cells in skin engineering.

  17. Development of a 3D cell printed construct considering angiogenesis for liver tissue engineering.

    Science.gov (United States)

    Lee, Jin Woo; Choi, Yeong-Jin; Yong, Woon-Jae; Pati, Falguni; Shim, Jin-Hyung; Kang, Kyung Shin; Kang, In-Hye; Park, Jaesung; Cho, Dong-Woo

    2016-01-12

    Several studies have focused on the regeneration of liver tissue in a two-dimensional (2D) planar environment, whereas actual liver tissue is three-dimensional (3D). Cell printing technology has been successfully utilized for building 3D structures; however, the poor mechanical properties of cell-laden hydrogels are a major concern. Here, we demonstrate the printing of a 3D cell-laden construct and its application to liver tissue engineering using 3D cell printing technology through a multi-head tissue/organ building system. Polycaprolactone (PCL) was used as a framework material because of its excellent mechanical properties. Collagen bioink containing three different types of cells-hepatocytes (HCs), human umbilical vein endothelial cells , and human lung fibroblasts--was infused into the canals of a PCL framework to induce the formation of capillary--like networks and liver cell growth. A co-cultured 3D microenvironment of the three types of cells was successfully established and maintained. The vascular formation and functional abilities of HCs (i.e., albumin secretion and urea synthesis) demonstrated that the heterotypic interaction among HCs and nonparenchymal cells increased the survivability and functionality of HCs within the collagen gel. Therefore, our results demonstrate the prospect of using cell printing technology for the creation of heterotypic cellular interaction within a structure for liver tissue engineering.

  18. Construction of tissue-engineered cartilage using human placenta-derived stem cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Human placenta-derived stem cells (hPDSCs) were isolated by trypsinization and further induced into cartilage cells in vitro.The engineered cartilage was constructed by combining hPDSCs with collagen sponge and the cartilage formation was observed by implantation into nude mice.Results showed that hPDSCs featured mesenchymal stem cells and maintained proliferation in vitro for over 30 passages while remaining undifferentiated.All results indicated that hPDSCs have the potential to differentiate into functional cartilage cells in vitro when combined with collagen sponge,which provided experimental evidence for prospective clinical application.

  19. Cellular Immune Response to an Engineered Cell-Based Tumor Vaccine at the Vaccination Site

    OpenAIRE

    Zhou,Qiang; Johnson, Bryon D.; Rimas J Orentas

    2007-01-01

    The engineered expression of the immune co-stimulatory molecules CD80 and CD137L on the surface of a neuroblastoma cell line converts this tumor into a cell-based cancer vaccine. The mechanism by which this vaccine activates the immune system was investigated by capturing and analyzing immune cells responding to the vaccine cell line embedded in a collagen matrix and injected subcutaneously. The vaccine induced a significant increase in the number of activated CD62L− CCR7− CD49b+ CD8 effector...

  20. Can Engineered “Designer” T Cells Outsmart Chronic Hepatitis B?

    Directory of Open Access Journals (Sweden)

    U. Protzer

    2010-01-01

    Full Text Available More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered “designer” T cells.

  1. Engineering skeletal muscle tissues from murine myoblast progenitor cells and application of electrical stimulation.

    Science.gov (United States)

    van der Schaft, Daisy W J; van Spreeuwel, Ariane C C; Boonen, Kristel J M; Langelaan, Marloes L P; Bouten, Carlijn V C; Baaijens, Frank P T

    2013-03-19

    Engineered muscle tissues can be used for several different purposes, which include the production of tissues for use as a disease model in vitro, e.g. to study pressure ulcers, for regenerative medicine and as a meat alternative (1). The first reported 3D muscle constructs have been made many years ago and pioneers in the field are Vandenburgh and colleagues (2,3). Advances made in muscle tissue engineering are not only the result from the vast gain in knowledge of biochemical factors, stem cells and progenitor cells, but are in particular based on insights gained by researchers that physical factors play essential roles in the control of cell behavior and tissue development. State-of-the-art engineered muscle constructs currently consist of cell-populated hydrogel constructs. In our lab these generally consist of murine myoblast progenitor cells, isolated from murine hind limb muscles or a murine myoblast cell line C2C12, mixed with a mixture of collagen/Matrigel and plated between two anchoring points, mimicking the muscle ligaments. Other cells may be considered as well, e.g. alternative cell lines such as L6 rat myoblasts (4), neonatal muscle derived progenitor cells (5), cells derived from adult muscle tissues from other species such as human (6) or even induced pluripotent stem cells (iPS cells) (7). Cell contractility causes alignment of the cells along the long axis of the construct (8,9) and differentiation of the muscle progenitor cells after approximately one week of culture. Moreover, the application of electrical stimulation can enhance the process of differentiation to some extent (8). Because of its limited size (8 x 2 x 0.5 mm) the complete tissue can be analyzed using confocal microscopy to monitor e.g. viability, differentiation and cell alignment. Depending on the specific application the requirements for the engineered muscle tissue will vary; e.g. use for regenerative medicine requires the up scaling of tissue size and vascularization, while

  2. Mechanics of Sheeting Joints

    Science.gov (United States)

    Martel, S. J.

    2015-12-01

    Physical breakdown of rock across a broad scale spectrum involves fracturing. In many areas large fractures develop near the topographic surface, with sheeting joints being among the most impressive. Sheeting joints share many geometric, textural, and kinematic features with other joints (opening-mode fractures) but differ in that they are (a) discernibly curved, (b) open near the topographic surface, and (c) form subparallel to the topographic surface. Where sheeting joints are geologically young, the surface-parallel compressive stresses are typically several MPa or greater. Sheeting joints are best developed beneath domes, ridges, and saddles; they also are reported, albeit rarely, beneath valleys or bowls. A mechanism that accounts for all these associations has been sought for more than a century: neither erosion of overburden nor high lateral compressive stresses alone suffices. Sheeting joints are not accounted for by Mohr-Coulomb shear failure criteria. Principles of linear elastic fracture mechanics, together with the mechanical effect of a curved topographic surface, do provide a basis for understanding sheeting joint growth and the pattern sheeting joints form. Compressive stresses parallel to a singly or doubly convex topographic surface induce a tensile stress perpendicular to the surface at shallow depths; in some cases this alone could overcome the weight of overburden to open sheeting joints. If regional horizontal compressive stresses, augmented by thermal stresses, are an order of magnitude or so greater than a characteristic vertical stress that scales with topographic amplitude, then topographic stress perturbations can cause sheeting joints to open near the top of a ridge. This topographic effect can be augmented by pressure within sheeting joints arising from water, ice, or salt. Water pressure could be particularly important in helping drive sheeting joints downslope beneath valleys. Once sheeting joints have formed, the rock sheets between

  3. Engineering PQS biosynthesis pathway for enhancement of bioelectricity production in pseudomonas aeruginosa microbial fuel cells.

    Directory of Open Access Journals (Sweden)

    Victor Bochuan Wang

    Full Text Available The biosynthesis of the redox shuttle, phenazines, in Pseudomonas aeruginosa, an ubiquitous microorganism in wastewater microflora, is regulated by the 2-heptyl-3,4-dihydroxyquinoline (PQS quorum-sensing system. However, PQS inhibits anaerobic growth of P. aeruginosa. We constructed a P. aeruginosa strain that produces higher concentrations of phenazines under anaerobic conditions by over-expressing the PqsE effector in a PQS negative ΔpqsC mutant. The engineered strain exhibited an improved electrical performance in microbial fuel cells (MFCs and potentiostat-controlled electrochemical cells with an approximate five-fold increase of maximum current density relative to the parent strain. Electrochemical analysis showed that the current increase correlates with an over-synthesis of phenazines. These results therefore demonstrate that targeting microbial cell-to-cell communication by genetic engineering is a suitable technique to improve power output of bioelectrochemical systems.

  4. Current status of engineered T-cell therapy for synovial sarcoma.

    Science.gov (United States)

    Dallos, Matthew; Tap, William D; D'Angelo, Sandra P

    2016-09-01

    Synovial sarcoma is a rare soft tissue sarcoma characterized by a t(X;18) translocation, which results in a SYT-SSX gene fusion. In the metastatic setting, chemotherapy has limited, durable efficacy prompting the necessity for new therapeutic modalities. One emerging new strategy involves T-cell-directed therapy such as tumor-infiltrating lymphocytes or the development of T cells that are genetically engineered to express a T-cell receptor against a cancer testis antigen. Of these approaches, engineered T cells that recognize NY-ESO-1 are the furthest along in development. Completed and on-going clinical trials have shown promise and there are efforts to continue to optimize the current approach.

  5. PROSPECTS FOR APPLICATION OF Aplysinidae FAMILY MARINE SPONGE SKELETONS AND MESENCHYMAL STROMAL CELLS IN TISSUE ENGINEERING

    Directory of Open Access Journals (Sweden)

    О. Yu. Rogulska

    2011-10-01

    Full Text Available Development of the new types of tissue engineered structures is one of the promising trends of current biotechnology. The study was directed to the assessment of prospects for the application of chitin-based skeletons derived from marine sponges of Aplysinidae family (Aplysina fulva and Aplysina aerophoba for creation of bioengineered constructs based on human mesenchymal stromal cells. After cleaning and demineralization procedures, sponge skeletons appeared as three-dimensional macroporous matrices formed by intersecting chitin fibrils. After seeding into chitin-based matrices the cells were attached to the surface of the fibrils and were able to spread and proliferate. Mesenchymal stromal cells within Aplysina fulva differentiated into osteogenic and adipogenic directions under the influence of appropriate inductors. Demineralized skeletons derived from marine sponges of Aplysinidae family could be used as scaffolds for mesenchymal stromal cells which provides new opportunities for the creation of adipose and bone tissue engineered structures.

  6. Automatically extracting sheet-metal features from solid model

    Institute of Scientific and Technical Information of China (English)

    刘志坚; 李建军; 王义林; 李材元; 肖祥芷

    2004-01-01

    With the development of modern industry, sheet-metal parts in mass production have been widely applied in mechanical, communication, electronics, and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry, feature matching, and feature relationship. Since the extracted features include abundant geometry and engineering information, they will be effective for downstream application such as feature rebuilding and stamping process planning.

  7. Automatically extracting sheet-metal features from solid model

    Institute of Scientific and Technical Information of China (English)

    刘志坚; 李建军; 王义林; 李材元; 肖祥芷

    2004-01-01

    With the development of modern industry,sheet-metal parts in mass production have been widely applied in mechanical,communication,electronics,and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry,feature matching,and feature relationship. Since the extracted features include abundant geometry and engineering information,they will be effective for downstream application such as feature rebuilding and stamping process planning.

  8. TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORAT

    Science.gov (United States)

    1963-01-01

    TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORATORY HEFL - TRANSDUCER INSTRUMENTATION CONSOLE SE-10 - TEMPERATURE INSTRUMENTATION CONSOLE SE-10 - MODULE FUEL CELL EXPERIMENT SE-8 -

  9. Engineered myocardial tissues constructed in vivo using cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells in rats

    Directory of Open Access Journals (Sweden)

    Xing Yujie

    2012-01-01

    Full Text Available Abstract Background To explore the feasibility of constructing engineered myocardial tissues (EMTs in vivo, using polylactic acid -co-glycolic acid (PLGA for scaffold and cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells (BMMSCs for seeded cells. Methods BMMSCs were isolated from femur and tibia of Sprague-Dawley (SD rats by density-gradient centrifugation. The third passage cells were treated with 10 μmol/L 5-azacytidine (5-aza and 0.1 μmol/L angiotensin II (Ang II for 24 h, followed by culturing in complete medium for 3 weeks to differentiated into cardiomyocyte-like cells. The cardiomyocyte-like cells were seeded into PLGA scaffolds to form the grafts. The grafts were cultured in the incubator for three days and then implanted into the peritoneal cavity of SD rats. Four weeks later, routine hematoxylin-eosin (HE staining, immunohistochemical staining for myocardium-specific cardiac troponin I (cTnI, scanning electron microscopy and transmission electron microscopy were used to analyze the morphology and microconstruction of the EMTs in host rats. Results HE staining showed that the cardiomyocyte-like cells distributed equally in the PLGA scaffold, and the nuclei arranged in the spindle shape. Immunohistochemical staining revealed that majority of engrafted cells in the PLGA -Cardiomyocyte-like cells group were positive for cTnI. Scanning electron microscopy showed that the inoculated cells well attached to PLGA and grew in 3 dimensions in construct. Transmission electron microscopy showed that the EMTs contained well arranged myofilaments paralleled to the longitudinal cell axis, the cells were rich in endoplasmic reticulum and mitochondria, while desmosomes, gap junction and Z line-like substances were also can be observed as well within the engrafted cells. Conclusion We have developed an in vivo method to construct engineered myocardial tissue. The in vivo microenvironment helped engrafted cells/tissue survive and

  10. Hydrogen-bonded LbL Shells for Living Cell Surface Engineering

    Science.gov (United States)

    2011-03-21

    phospholipids into the lipid bilayer membrane, and cell decoration with/inclusion into biodegradable gel microparti- cles.7–11 However, for these strategies...polymer membrane. The poly(allylamine hydrochloride)/poly(styrene sulfonate) ( PAH /PSS) coating is the mostly explored poly- electrolyte pair used to...this approach for cell surface engineering.42,43 As suggested, overall toxicity of the PAH /PSS LbL shells originates from the positive charge of

  11. Overview of KRAS-Driven Genetically Engineered Mouse Models of Non-Small Cell Lung Cancer.

    Science.gov (United States)

    Sheridan, Clare; Downward, Julian

    2015-01-01

    KRAS, the most frequently mutated oncogene in non-small cell lung cancer, has been utilized extensively to model human lung adenocarcinomas. The results from such studies have enhanced considerably an understanding of the relationship between KRAS and the development of lung cancer. Detailed in this overview are the features of various KRAS-driven genetically engineered mouse models (GEMMs) of non-small cell lung cancer, their utilization, and the potential of these models for the study of lung cancer biology.

  12. Trends and approaches in N-Glycosylation engineering in Chinese hamster ovary cell culture

    DEFF Research Database (Denmark)

    Fan, Yuzhou; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    will summarize a group of recent strategies andapproaches and come up with case studies for N-glycosylation engineering in CHO cells and show several examples of relevantstudy cases from our research: 1) media and feed design, 2) culture process optimization, 3) substrate addition, 4) geneticengineering, 5...

  13. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  14. Trends and approaches in N-Glycosylation engineering in Chinese hamster ovary cell culture

    DEFF Research Database (Denmark)

    Fan, Yuzhou; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    , in particular, of those as drug substances, is extremely concerned in drug development andapproval, as it will largely affect their stability, efficacy, clearance rate and immunogenicity. Therefore to engineering N-glycosylationof CHO cell-derived recombinant proteins are extremely important. Here, we...

  15. Platelet-Rich Blood Derivatives for Stem Cell-Based Tissue Engineering and Regeneration

    NARCIS (Netherlands)

    Masoudi, E.A.; Ribas, J.; Kaushik, G.; Leijten, J.C.H.; Khademhosseini, A.

    2016-01-01

    Platelet-rich blood derivatives have been widely used in different fields of medicine and stem cell-based tissue engineering. They represent natural cocktails of autologous growth factors, which could provide an alternative for recombinant protein-based approaches. Platelet-rich blood derivatives, s

  16. In situ tissue engineering of functional small-diameter blood vessels by host circulating cells only

    NARCIS (Netherlands)

    Talacua, Hanna; Smits, Anthal I P M; Muylaert, Dimitri E P; Van Rijswijk, Jan Willem; Vink, Aryan; Verhaar, Marianne C.; Driessen-Mol, Anita; Van Herwerden, Lex A.; Bouten, Carlijn V C; Kluin, Jolanda; Baaijens, Frank P T

    2015-01-01

    Inflammation is a natural phase of the wound healing response, which can be harnessed for the in situ tissue engineering of small-diameter blood vessels using instructive, bioresorbable synthetic grafts. This process is dependent on colonization of the graft by host circulating cells and subsequent

  17. Comparative DNA damage and transcriptomic effects of engineered nanoparticles in human lung cells in vitro

    Science.gov (United States)

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), various types of DNA damage, and transcriptional changes in human respiratory BEAS-2B cells exposed in vitro at se...

  18. Human umbilical cord stem cell encapsulation in novel macroporous and injectable fibrin for muscle tissue engineering

    Science.gov (United States)

    Liu, Jun; Xu, Hockin H.K.; Zhou, Hongzhi; Weir, Michael D.; Chen, Qianming; Trotman, Carroll Ann

    2012-01-01

    There has been little research on the seeding of human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of this study were: (i) to seed hUCMSCs in a fibrin hydrogel containing fast-degradable microbeads (dMBs) to create macropores to enhance cell viability; and (ii) to investigate the encapsulated cell proliferation and myogenic differentiation for muscle tissue engineering. Mass fractions of 0–80% of dMBs were tested, and 35% of dMBs in fibrin was shown to avoid fibrin shrinkage while creating macropores and promoting cell viability. This construct was referred to as “dMB35”. Fibrin without dMBs was termed “dMB0”. Microbead degradation created macropores in fibrin and improved cell viability. The percentage of live cells in dMB35 reached 91% at 16 days, higher than the 81% in dMB0 (p muscle tissue engineering applications. PMID:22902812

  19. Stem cells and biopharmaceuticals: vital roles in the growth of tissue-engineered small intestine.

    Science.gov (United States)

    Belchior, Gustavo Gross; Sogayar, Mari Cleide; Grikscheit, Tracy Cannon

    2014-06-01

    Tissue engineering currently constitutes a complex, multidisciplinary field exploring ideal sources of cells in combination with scaffolds or delivery systems in order to form a new, functional organ to replace native organ lack or loss. Short bowel syndrome (SBS) is a life-threatening condition with high morbidity and mortality rates in children. Current therapeutic strategies consist of costly and risky allotransplants that demand lifelong immunosuppression. A promising alternative is the implantation of autologous organoid units (OU) to create a tissue-engineered small intestine (TESI). This strategy is proven to be stem cell and mesenchyme dependent. Intestinal stem cells (ISCs) are located at the base of the crypt and are responsible for repopulating the cycling mucosa up to the villus tip. The stem cell niche governs the biology of ISCs and, together with the rest of the epithelium, communicates with the underlying mesenchyme to sustain intestinal homeostasis. Biopharmaceuticals are broadly used in the clinic to activate or enhance known signaling pathways and may greatly contribute to the development of a full-thickness intestine by increasing mucosal surface area, improving blood supply, and determining stem cell fate. This review will focus on tissue engineering as a means of building the new small intestine, highlighting the importance of stem cells and recombinant peptide growth factors as biopharmaceuticals.

  20. Bioethanol Production from Uncooked Raw Starch by Immobilized Surface-engineered Yeast Cells

    Science.gov (United States)

    Chen, Jyh-Ping; Wu, Kuo-Wei; Fukuda, Hideki

    Surface-engineered yeast Saccharomyces cerevisiae codisplaying Rhizopus oryzae glucoamylase and Streptococcus bovis α-amylase on the cell surface was used for direct production of ethanol from uncooked raw starch. By using 50 g/L cells during batch fermentation, ethanol concentration could reach 53 g/L in 7 days. During repeated batch fermentation, the production of ethanol could be maintained for seven consecutive cycles. For cells immobilized in loofa sponge, the concentration of ethanol could reach 42 g/L in 3 days in a circulating packed-bed bioreactor. However, the production of ethanol stopped thereafter because of limited contact between cells and starch. The bioreactor could be operated for repeated batch production of ethanol, but ethanol concentration dropped to 55% of its initial value after five cycles because of a decrease in cell mass and cell viability in the bioreactor. Adding cells to the bioreactor could partially restore ethanol production to 75% of its initial value.

  1. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vinicius Rosa

    2016-01-01

    Full Text Available Stem cells from human exfoliated deciduous teeth (SHED are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates. The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies.

  2. Stem cell therapy and cellular engineering for treatment of neuronal dysfunction in Huntington's disease.

    Science.gov (United States)

    Choi, Kyung-Ah; Hwang, Insik; Park, Hang-soo; Oh, Seung-Ick; Kang, Seongman; Hong, Sunghoi

    2014-07-01

    Huntington's disease (HD) is a fatal inherited neurodegenerative disorder characterized by progressive loss of neurons in the striatum, a sub-cortical region of the forebrain. The sub-cortical region of the forebrain is associated with the control of movement and behavior, thus HD initially presents with coordination difficulty and cognitive decline. Recent reprogramming technologies, including induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs), have created opportunities to understand the pathological cascades that underlie HD and to develop new treatments for this currently incurable neurological disease. The ultimate objectives of stem cell-based therapies for HD are to replace lost neurons and to prevent neuronal dysfunction and death. In this review, we examine the current understanding of the molecular and pathological mechanisms involved in HD. We discuss disease modeling with HD-iPSCs derived from the somatic cells of patients, which could provide an invaluable platform for understanding HD pathogenesis. We speculate about the benefits and drawbacks of using iNSCs as an alternative stem cell source for HD treatment. Finally, we discuss cell culture and engineering systems that promote the directed differentiation of pluripotent stem cell-derived NSCs into a striatal DARPP32(+) GABAergic MSN phenotype for HD. In conclusion, this review summarizes the potentials of cell reprogramming and engineering technologies relevant to the development of cell-based therapies for HD.

  3. Cardiac tissue engineering: cell seeding, cultivation parameters, and tissue construct characterization.

    Science.gov (United States)

    Carrier, R L; Papadaki, M; Rupnick, M; Schoen, F J; Bursac, N; Langer, R; Freed, L E; Vunjak-Novakovic, G

    1999-09-01

    Cardiac tissue engineering has been motivated by the need to create functional tissue equivalents for scientific studies and cardiac tissue repair. We previously demonstrated that contractile cardiac cell-polymer constructs can be cultivated using isolated cells, 3-dimensional scaffolds, and bioreactors. In the present work, we examined the effects of (1) cell source (neonatal rat or embryonic chick), (2) initial cell seeding density, (3) cell seeding vessel, and (4) tissue culture vessel on the structure and composition of engineered cardiac muscle. Constructs seeded under well-mixed conditions with rat heart cells at a high initial density ((6-8) x 10(6) cells/polymer scaffold) maintained structural integrity and contained macroscopic contractile areas (approximately 20 mm(2)). Seeding in rotating vessels (laminar flow) rather than mixed flasks (turbulent flow) resulted in 23% higher seeding efficiency and 20% less cell damage as assessed by medium lactate dehydrogenase levels (p laminar and dynamic, yielded constructs with a more active, aerobic metabolism as compared to constructs cultured in mixed or static flasks. After 1-2 weeks of cultivation, tissue constructs expressed cardiac specific proteins and ultrastructural features and had approximately 2-6 times lower cellularity (p < 0.05) but similar metabolic activity per unit cell when compared to native cardiac tissue.

  4. TRAIL-engineered pancreas-derived mesenchymal stem cells: characterization and cytotoxic effects on pancreatic cancer cells.

    Science.gov (United States)

    Moniri, M R; Sun, X-Y; Rayat, J; Dai, D; Ao, Z; He, Z; Verchere, C B; Dai, L-J; Warnock, G L

    2012-09-01

    Mesenchymal stem cells (MSCs) have attracted great interest in cancer therapy owing to their tumor-oriented homing capacity and the feasibility of autologous transplantation. Currently, pancreatic cancer patients face a very poor prognosis, primarily due to the lack of therapeutic strategies with an effective degree of specificity. Anticancer gene-engineered MSCs specifically target tumor sites and can produce anticancer agents locally and constantly. This study was performed to characterize pancreas-derived MSCs and investigate the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-engineered MSCs on pancreatic cancer cells under different culture conditions. Pancreas-derived MSCs exhibited positive expression on CD44, CD73, CD95, CD105, negative on CD34 and differentiated into adipogenic and osteogenic cells. TRAIL expression was assessed by both enzyme-linked immunosorbent assay and western blot analysis. Different patterns of TRAIL receptor expression were observed on the pancreatic cancer cell lines, including PANC1, HP62, ASPC1, TRM6 and BXPC3. Cell viability was assessed using a real-time monitoring system. Pancreatic cancer cell death was proportionally related to conditioned media from MSC(nsTRAIL) and MSC(stTRAIL). The results suggest that MSCs exhibit intrinsic inhibition of pancreatic cancer cells and that this effect can be potentiated by TRAIL-transfection on death receptor-bearing cell types.

  5. Dielectric and diffusion barrier multilayer for Cu(In,Ga)Se{sub 2} solar cells integration on stainless steel sheet

    Energy Technology Data Exchange (ETDEWEB)

    Amouzou, Dodji, E-mail: dodji.amouzou@fundp.ac.be [Research Centre in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Rue de Bruxelles, 61, 5000 Namur (Belgium); Guaino, Philippe; Fourdrinier, Lionel; Richir, Jean-Baptiste; Maseri, Fabrizio [CRM-Group, Boulevard de Colonster, B 57, 4000 Liège (Belgium); Sporken, Robert [Research Centre in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), Rue de Bruxelles, 61, 5000 Namur (Belgium)

    2013-09-02

    For the fabrication of monolithically integrated flexible Cu(In, Ga)Se{sub 2}, CIGS modules on stainless steel, individual photovoltaic cells must be insulated from metal substrates by a barrier layer that can sustain high thermal treatments. In this work, a combination of sol–gel (organosilane-sol) and sputtered SiAlxOy forming thin diffusion barrier layers (TDBL) was prepared on stainless steel substrates. The deposition of organosilane-sol dielectric layers on the commercial stainless steel (maximal roughness, Rz = 500 nm and Root Mean Square roughness, RMS = 56 nm) induces a planarization of the surface (RMS = 16.4 nm, Rz = 176 nm). The DC leakage current through the dielectric layers was measured for the metal-insulator-metal (MIM) junctions that act as capacitors. This method allowed us to assess the quality of our TDBL insulating layer and its lateral uniformity. Indeed, evaluating a ratio of the number of valid MIM capacitors to the number of tested MIM capacitors, a yield of ∼ 95% and 50% has been reached respectively with non-annealed and annealed samples based on sol–gel double layers. A yield of 100% was achieved for sol–gel double layers reinforced with a sputtered SiAlxOy coating and a third sol–gel monolayer. Since this yield is obtained on several samples, it can be extrapolated to any substrate size. Furthermore, according to Glow Discharge Optical Emission Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy measurements, these barrier layers exhibit excellent barrier properties against the diffusion of undesired atoms which could otherwise spoil the electronic and optical properties of CIGS photovoltaic cells. - Highlights: • We functionalize steel for monolithically integrated Cu(In,Ga)Se{sub 2} solar cells • Thin dielectric and diffusion barrier layers (TDDBL) prepared on steel • Reliability and breakdown voltage of dielectric layers have been studied. • Investigation of thermal treatment effect on dielectric

  6. The experimental study of genetic engineering human neural stem cells mediated by lentivirus to express multigene

    Institute of Scientific and Technical Information of China (English)

    CAI Pei-qiang; TANG Xun; LIN Yue-qiu; Oudega Martin; SUN Guang-yun; XU Lin; YANG Yun-kang; ZHOU Tian-hua

    2006-01-01

    Objective:To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs)mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI).Methods: Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3(NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot.Results: Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot.Conclusions: Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.

  7. High Field Sodium MRI Assessment of Stem Cell Chondrogenesis in a Tissue-Engineered Matrix.

    Science.gov (United States)

    Majumdar, Shreyan; Pothirajan, Padmabharathi; Dorcemus, Deborah; Nukavarapu, Syam; Kotecha, Mrignayani

    2016-04-01

    The development of non-invasive assessment techniques in vitro and in vivo is essential for monitoring and evaluating the growth of engineered cartilage tissues. Magnetic resonance imaging (MRI) is the leading non-invasive imaging modality used for assessing engineered cartilage. Typical MRI uses water proton relaxation times (T1 and T2) and apparent diffusion coefficient (ADC) to assess tissue growth. These techniques, while excellent in providing the first assurance of tissue growth, are unspecific to monitor the progress of engineered cartilage extracellular matrix components. In the current article, we present high field (11.7 T, (1)H freq. = 500 MHz) sodium MRI assessment of tissue-engineered cartilage at the early stage of tissue growth in vitro. We observed the chondrogenesis of human bone marrow derived stromal cells seeded in a gradient polymer-hydrogel matrix made out of poly(85 lactide-co-15 glycolide)--PuraMatrix™ for 4 weeks. We calculated the sodium concentration in the engineered constructs using a model of sodium MRI voxels that takes into account scaffold volume, cell density and amount of glycosaminoglycan (GAG). The sodium concentration was then converted to the fixed charge density (FCD) and compared with FCD derived from biochemical GAG analysis. Despite the small amount of GAG present in the engineered constructs, the sodium MRI derived FCD is found to be correlated (Pearson correlation coefficient R = 0.79) with the FCD derived from biochemical analysis. We conclude that sodium MRI could prove to be an invaluable tool in assessing engineered cartilage quantitatively during the repair or regeneration of cartilage defects.

  8. Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass.

    Science.gov (United States)

    Jordan, Adam; Chandler, Jenna; MacCready, Joshua S; Huang, Jingcheng; Osteryoung, Katherine W; Ducat, Daniel C

    2017-02-24

    Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends upon the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology in order to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus sp. PCC 7942. The Min system has established functions in controlling cell division by regulating assembly of FtsZ, a tubulin-like protein required to define the bacterial division plane. We show that altering expression of two FtsZ-regulatory proteins, MinC and Cdv3, permits control over cell morphology by disrupting FtsZ localization and cell division, without preventing continued cell growth. By varying the expression of these proteins, we can tune the length of cyanobacterial cells across a broad dynamic range: anywhere from a ∼20% increased length relative to wildtype to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach towards decreasing harvesting and processing costs associated with mass cyanobacterial cultivation through altering morphology at the cellular level.Importance: We show that the cell length of a model cyanobacterial species can be programmed through the rational manipulation of expression of protein factors that suppress cell division. In some instances, we are able to increase the size of these cells to near millimeter lengths through this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore

  9. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions.

    Science.gov (United States)

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C; Alexander, Morgan R; Langer, Robert; Anderson, Daniel G; Jaenisch, Rudolf

    2011-11-15

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell migration, and results in significant increases in cell growth of undifferentiated cells. These chemically defined xeno-free substrates generate more than three times the number of cells than feeder-containing substrates per surface area. Further, reprogramming and typical gene-targeting protocols can be readily performed on these engineered surfaces. These substrates provide an attractive cell culture platform for the production of clinically relevant factor-free reprogrammed cells from patient tissue samples and facilitate the definition of standardized scale-up friendly methods for disease modeling and cell therapeutic applications.

  10. Corneal stem cells and tissue engineering: Current advances and future perspectives.

    Science.gov (United States)

    de Araujo, Aline Lütz; Gomes, José Álvaro Pereira

    2015-06-26

    Major advances are currently being made in regenerative medicine for cornea. Stem cell-based therapies represent a novel strategy that may substitute conventional corneal transplantation, albeit there are many challenges ahead given the singularities of each cellular layer of the cornea. This review recapitulates the current data on corneal epithelial stem cells, corneal stromal stem cells and corneal endothelial cell progenitors. Corneal limbal autografts containing epithelial stem cells have been transplanted in humans for more than 20 years with great successful rates, and researchers now focus on ex vivo cultures and other cell lineages to transplant to the ocular surface. A small population of cells in the corneal endothelium was recently reported to have self-renewal capacity, although they do not proliferate in vivo. Two main obstacles have hindered endothelial cell transplantation to date: culture protocols and cell delivery methods to the posterior cornea in vivo. Human corneal stromal stem cells have been identified shortly after the recognition of precursors of endothelial cells. Stromal stem cells may have the potential to provide a direct cell-based therapeutic approach when injected to corneal scars. Furthermore, they exhibit the ability to deposit organized connective tissue in vitro and may be useful in corneal stroma engineering in the future. Recent advances and future perspectives in the field are discussed.

  11. Engineering targeted chromosomal amplifications in human breast epithelial cells.

    Science.gov (United States)

    Springer, Simeon; Yi, Kyung H; Park, Jeenah; Rajpurohit, Anandita; Price, Amanda J; Lauring, Josh

    2015-07-01

    Chromosomal amplifications are among the most common genetic alterations found in human cancers. However, experimental systems to study the processes that lead to specific, recurrent amplification events in human cancers are lacking. Moreover, some common amplifications, such as that at 8p11-12 in breast cancer, harbor multiple driver oncogenes, which are poorly modeled by conventional overexpression approaches. We sought to develop an experimental system to model recurrent chromosomal amplification events in human cell lines. Our strategy is to use homologous-recombination-mediated gene targeting to deliver a dominantly selectable, amplifiable marker to a specified chromosomal location. We used adeno-associated virus vectors to target human MCF-7 breast cancer cells at the ZNF703 locus, in the recurrent 8p11-12 amplicon, using the E. coli inosine monophosphate dehydrogenase (IMPDH) enzyme as a marker. We applied selective pressure using IMPDH inhibitors. Surviving clones were found to have increased copy number of ZNF703 (average 2.5-fold increase) by droplet digital PCR and FISH. Genome-wide array comparative genomic hybridization confirmed that amplifications had occurred on the short arm of chromosome 8, without changes on 8q or other chromosomes. Patterns of amplification were variable and similar to those seen in primary human breast cancers, including "sawtooth" patterns, distal copy number loss, and large continuous regions of copy number gain. This system will allow study of the cis- and trans-acting factors that are permissive for chromosomal amplification and provide a model to analyze oncogene cooperativity in amplifications harboring multiple candidate driver genes.

  12. Ultrasound Technologies for the Spatial Patterning of Cells and Extracellular Matrix Proteins and the Vascularization of Engineered Tissue

    Science.gov (United States)

    Garvin, Kelley A.

    Technological advancements in the field of tissue engineering could save the lives of thousands of organ transplant patients who die each year while waiting for donor organs. Currently, two of the primary challenges preventing tissue engineers from developing functional replacement tissues and organs are the need to recreate complex cell and extracellular microenvironments and to vascularize the tissue to maintain cell viability and function. Ultrasound is a form of mechanical energy that can noninvasively and nondestructively interact with tissues at the cell and protein level. In this thesis, novel ultrasound-based technologies were developed for the spatial patterning of cells and extracellular matrix proteins and the vascularization of three-dimensional engineered tissue constructs. Acoustic radiation forces associated with ultrasound standing wave fields were utilized to noninvasively control the spatial organization of cells and cell-bound extracellular matrix proteins within collagen-based engineered tissue. Additionally, ultrasound induced thermal mechanisms were exploited to site-specifically pattern various extracellular matrix collagen microstructures within a single engineered tissue construct. Finally, ultrasound standing wave field technology was used to promote the rapid and extensive vascularization of three-dimensional tissue constructs. As such, the ultrasound technologies developed in these studies have the potential to provide the field of tissue engineering with novel strategies to spatially pattern cells and extracellular matrix components and to vascularize engineered tissue, and thus, could advance the fabrication of functional replacement tissues and organs in the field of tissue engineering.

  13. Generation of functionally competent and durable engineered blood vessels from human induced pluripotent stem cells.

    Science.gov (United States)

    Samuel, Rekha; Daheron, Laurence; Liao, Shan; Vardam, Trupti; Kamoun, Walid S; Batista, Ana; Buecker, Christa; Schäfer, Richard; Han, Xiaoxing; Au, Patrick; Scadden, David T; Duda, Dan G; Fukumura, Dai; Jain, Rakesh K

    2013-07-30

    Efficient generation of competent vasculogenic cells is a critical challenge of human induced pluripotent stem (hiPS) cell-based regenerative medicine. Biologically relevant systems to assess functionality of the engineered vessels in vivo are equally important for such development. Here, we report a unique approach for the derivation of endothelial precursor cells from hiPS cells using a triple combination of selection markers--CD34, neuropilin 1, and human kinase insert domain-containing receptor--and an efficient 2D culture system for hiPS cell-derived endothelial precursor cell expansion. With these methods, we successfully generated endothelial cells (ECs) from hiPS cells obtained from healthy donors and formed stable functional blood vessels in vivo, lasting for 280 d in mice. In addition, we developed an approach to generate mesenchymal precursor cells (MPCs) from hiPS cells in parallel. Moreover, we successfully generated functional blood vessels in vivo using these ECs and MPCs derived from the same hiPS cell line. These data provide proof of the principle that autologous hiPS cell-derived vascular precursors can be used for in vivo applications, once safety and immunological issues of hiPS-based cellular therapy have been resolved. Additionally, the durability of hiPS-derived blood vessels in vivo demonstrates a potential translation of this approach in long-term vascularization for tissue engineering and treatment of vascular diseases. Of note, we have also successfully generated ECs and MPCs from type 1 diabetic patient-derived hiPS cell lines and use them to generate blood vessels in vivo, which is an important milestone toward clinical translation of this approach.

  14. Release of tissue inhibitor of metalloproteinase-2 from alginate microcapsule encapsulating genetically engineered cells

    Directory of Open Access Journals (Sweden)

    Kim YS

    2013-11-01

    Full Text Available Yeon Seong Kim,1,* Young-Il Jeong,2,* Shu-Guang Jin,2 Jian Pei,2 Min Wen,2 In-Young Kim,1 Kyung-Sub Moon,1 Tae-Young Jung,1 Hyang-Hwa Ryu2, Shin Jung1–3 1Department of Neurosurgery, 2Brain Tumor Research Laboratory, 3Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Jeollanam-do, Korea *These authors contributed equally to this work Background: In this study, 293T cells were genetically engineered to secrete tissue inhibitor of metalloproteinase-2 (TIMP2 and encapsulated into alginate microcapsules to continuously release TIMP2 protein. Methods: The anti-invasive potential of the microcapsules was studied in vitro using brain tumor cells. The TIMP2 gene was transfected to 293T cells, and genetically engineered 293TIMP2 cells were encapsulated into alginate microcapsules. Release of TIMP2 protein was detected with Western blot analysis and the anti-invasive potential against U87MG cells was tested using gelatin zymography and a Matrigel assay. Results: Cell viability within the alginate microcapsules was maintained at a cell density of 5 × 106. Because polycationic polymers are helpful for maintaining the mechanical strength of microcapsules with good cell viability, the alginate microcapsules were reinforced with chitosan (0.1% w/v. Expression of TIMP2 protein in cell lysates and secretion of TIMP2 into the conditioned medium was confirmed by Western blot analysis. Alginate microcapsules encapsulating 293TIMP2 cells released TIMP2 protein into the medium efficiently, where the TIMP2 protein participated in degradation of the matrix metalloproteinase-2 enzyme and inhibited invasion of U87MG cells. Conclusion: Alginate microcapsules encapsulating 293TIMP2 cells are promising candidates for anti-invasive treatment of glioma. Keywords: 293T cells, tissue inhibitor of metalloproteinase-2, alginate microcapsule, therapeutic protein

  15. Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

    Science.gov (United States)

    Smith, W. A.; Lam, K.-P.; Dempsey, K. P.; Mazzocchi-Jones, D.; Richardson, J. B.; Yang, Y.

    2014-02-01

    Within the field of tissue engineering there is an emphasis on studying 3-D live tissue structures. Consequently, to investigate and identify cellular activities and phenotypes in a 3-D environment for all in vitro experiments, including shape, migration/proliferation and axon projection, it is necessary to adopt an optical imaging system that enables monitoring 3-D cellular activities and morphology through the thickness of the construct for an extended culture period without cell labeling. This paper describes a new 3-D tracking algorithm developed for Cell-IQ®, an automated cell imaging platform, which has been equipped with an environmental chamber optimized to enable capturing time-lapse sequences of live cell images over a long-term period without cell labeling. As an integral part of the algorithm, a novel auto-focusing procedure was developed for phase contrast microscopy equipped with 20x and 40x objectives, to provide a more accurate estimation of cell growth/trajectories by allowing 3-D voxels to be computed at high spatiotemporal resolution and cell density. A pilot study was carried out in a phantom system consisting of horizontally aligned nanofiber layers (with precise spacing between them), to mimic features well exemplified in cellular activities of neuronal growth in a 3-D environment. This was followed by detailed investigations concerning axonal projections and dendritic circuitry formation in a 3-D tissue engineering construct. Preliminary work on primary animal neuronal cells in response to chemoattractant and topographic cue within the scaffolds has produced encouraging results.

  16. Genetically engineered K cells provide sufficient insulin to correct hyperglycemia in a nude murine model

    Institute of Scientific and Technical Information of China (English)

    Yiqun Zhang; Liqing Yao; Kuntang Shen; Meidong Xu; Pinghong Zhou; Weige Yang; Xinyuan Liu; Xinyu Qin

    2008-01-01

    A gene therapy-based treatment of type 1 diabetes mellitus requires the development of a surrogate β cell that can synthesize and secrete functionally active insulin in response to physiologically relevant changes in ambient glucose levels. In this study, the murine enteroendocrine cell line STC-1 was genetically modified by stable transfection. Two clone cells were selected (STC-1-2 and STC-1-14) that secreted the highest levels of insulin among the 22 clones expressing insulin from 0 to 157.2 μIU/ml/106 cells/d. After glucose concentration in the culture medium was increased from 1 mM to 10 mM, secreted insulin rose from 40.3±0.8 to 56.3±3.2 μIU/ml (STC-1-2), and from 10.8±0.8 to 23.6±2.3 μIU/ml (STC-1-14). After STC-1-14 cells were implanted into diabetic nude mice, their blood glucose levels were reduced to normal. Body weight loss was also ameliorated. Our data suggested that genetically engineered K cells secrete active insulin in a glucose-regulated manner, and in vivo study showed that hyperglycemia could be reversed by implantation of the cells, suggesting that the use of genetically engineered K cells to express human insulin might provide a glucose-regulated approach to treat diabetic hyperglycemia.

  17. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  18. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  19. Red blood cell engineering in stroma and serum/plasma-free conditions and long term storage.

    Science.gov (United States)

    Kim, Hyun Ok; Baek, Eun Jung

    2012-01-01

    In vitro generation of artificial red blood cells (RBCs) is very important to overcome insufficient and unsafe blood supply. Despite recent progresses in RBCs engineering from several stem cell sources, none of them could succeed in generation of functional RBCs in the absence of serum/plasma and feeder cells. Without the elimination of serum and plasma, human RBC engineering in a large scale is impossible, especially for the future bioreactor system. Using an appropriate combination of cost-effective and safe reagents, the present study demonstrated the terminal maturation of hematopoietic stem cells into enucleated RBCs, which were functional comparable to donated human RBCs. Surprisingly, the viability of erythroid cells was higher in our serum- and feeder-free culture condition than in the previous serum-added condition. This was possible by supplementation with vitamin C in media and hypothermic conditions. Also, our report firstly presents the storability of artificial RBCs, which possibility is essential for clinical application. In summary, our report demonstrates engineering of human applicable RBCs with a dramatically enhanced viability and shelf-life in both serum- and stroma-free conditions. This innovative culture technology could contribute to the realization of the large-scale pharming of human RBCs using bioreactor systems.

  20. Preparation and properties of microencapsulated genetically engineered bacteria cells for oral therapy of uremia

    Institute of Scientific and Technical Information of China (English)

    GAO Hong; YU Yaoting; CAI Baoli; WANG Manyan

    2004-01-01

    Microencapsulated genetically engineered bacteria cells are a novel approach of oral therapy for uremia.Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5α cells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease genetically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engineered bacterial cells are: polyvinyl alcohol (PVA, 2450±50)used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h,entrapment ratio of bacteria 8%, air flow rate of the encapsulate device 3 L/min and liquid flow rate at 1 mL/10 min.The average diameter of microcapsules prepared under these optimal conditions is 20-40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.

  1. Materials from Mussel-Inspired Chemistry for Cell and Tissue Engineering Applications.

    Science.gov (United States)

    Madhurakkat Perikamana, Sajeesh Kumar; Lee, Jinkyu; Lee, Yu Bin; Shin, Young Min; Lee, Esther J; Mikos, Antonios G; Shin, Heungsoo

    2015-09-14

    Current advances in biomaterial fabrication techniques have broadened their application in different realms of biomedical engineering, spanning from drug delivery to tissue engineering. The success of biomaterials depends highly on the ability to modulate cell and tissue responses, including cell adhesion, as well as induction of repair and immune processes. Thus, most recent approaches in the field have concentrated on functionalizing biomaterials with different biomolecules intended to evoke cell- and tissue-specific reactions. Marine mussels produce mussel adhesive proteins (MAPs), which help them strongly attach to different surfaces, even under wet conditions in the ocean. Inspired by mussel adhesiveness, scientists discovered that dopamine undergoes self-polymerization at alkaline conditions. This reaction provides a universal coating for metals, polymers, and ceramics, regardless of their chemical and physical properties. Furthermore, this polymerized layer is enriched with catechol groups that enable immobilization of primary amine or thiol-based biomolecules via a simple dipping process. Herein, this review explores the versatile surface modification techniques that have recently been exploited in tissue engineering and summarizes polydopamine polymerization mechanisms, coating process parameters, and effects on substrate properties. A brief discussion of polydopamine-based reactions in the context of engineering various tissue types, including bone, blood vessels, cartilage, nerves, and muscle, is also provided.

  2. Glycopolymer functionalization of engineered spider silk protein-based materials for improved cell adhesion.

    Science.gov (United States)

    Hardy, John G; Pfaff, André; Leal-Egaña, Aldo; Müller, Axel H E; Scheibel, Thomas R

    2014-07-01

    Silk protein-based materials are promising biomaterials for application as tissue scaffolds, due to their processability, biocompatibility, and biodegradability. The preparation of films composed of an engineered spider silk protein (eADF4(C16)) and their functionalization with glycopolymers are described. The glycopolymers bind proteins found in the extracellular matrix, providing a biomimetic coating on the films that improves cell adhesion to the surfaces of engineered spider silk films. Such silk-based materials have potential as coatings for degradable implantable devices.

  3. Device Engineering Towards Improved Tin Sulfide Solar Cell Performance and Performance Reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul; Siol, Sebastian; Martinot, Loic; Polizzotti, Alex; Yang, Chuanxi; Hartman, Katy; Gradecak, Silvija; Zakutayev, Andriy; Gordon, Roy G.; Buonassisi, Tonio

    2016-11-21

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to rapidly test promising candidates in high-performing PV devices. There is a need to engineer new compatible device architectures, including the development of novel transparent conductive oxides and buffer layers. Here, we consider the two approaches of a substrate-style and a superstrate-style device architecture for novel thin-film solar cells. We use tin sulfide as a test absorber material. Upon device engineering, we demonstrate new approaches to improve device performance and performance reproducibility.

  4. A novel engineered meganuclease induces homologous recombination in yeast and mammalian cells.

    Science.gov (United States)

    Epinat, Jean-Charles; Arnould, Sylvain; Chames, Patrick; Rochaix, Pascal; Desfontaines, Dominique; Puzin, Clémence; Patin, Amélie; Zanghellini, Alexandre; Pâques, Frédéric; Lacroix, Emmanuel

    2003-06-01

    Homologous gene targeting is the ultimate tool for reverse genetics, but its use is often limited by low efficiency. In a number of recent studies, site- specific DNA double-strand breaks (DSBs) have been used to induce efficient gene targeting. Engineering highly specific, dedicated DNA endonucleases is the key to a wider usage of this technology. In this study, we present two novel, chimeric meganucleases, derived from homing endonucleases. The first one is able to induce recombination in yeast and mammalian cells, whereas the second cleaves a novel (chosen) DNA target site. These results are a first step toward the generation of custom endonucleases for the purpose of targeted genome engineering.

  5. Rapid prototyping of microbial cell factories via genome-scale engineering.

    Science.gov (United States)

    Si, Tong; Xiao, Han; Zhao, Huimin

    2015-11-15

    Advances in reading, writing and editing genetic materials have greatly expanded our ability to reprogram biological systems at the resolution of a single nucleotide and on the scale of a whole genome. Such capacity has greatly accelerated the cycles of design, build and test to engineer microbes for efficient synthesis of fuels, chemicals and drugs. In this review, we summarize the emerging technologies that have been applied, or are potentially useful for genome-scale engineering in microbial systems. We will focus on the development of high-throughput methodologies, which may accelerate the prototyping of microbial cell factories.

  6. Emergence of Form from Function - Mechanical Engineering Approaches to Probe the Role of Stem Cell Mechanoadaptation in Sealing Cell Fate.

    Science.gov (United States)

    Knothe Tate, Melissa L; Gunning, Peter W; Sansalone, Vittorio

    2016-10-14

    Stem cell "mechanomics" refers to the effect of mechanical cues on stem cell and matrix biology, where cell shape and fate are intrinsic manifestations of form and function. Before specialization, the stem cell itself serves as a sensor and actuator; its structure emerges from its local mechanical milieu as the cell adapts over time. Coupling of novel spatiotemporal imaging and computational methods allows for linking of the energy of adaptation to the structure, biology and mechanical function of the cell. Cutting edge imaging methods enable probing of mechanisms by which stem cells' emergent anisotropic architecture and fate commitment occurs. A novel cell-scale model provides a mechanistic framework to describe stem cell growth and remodeling through mechanical feedback; making use of a generalized virtual power principle, the model accounts for the rate of doing work or the rate of using energy to effect the work. This coupled approach provides a basis to elucidate mechanisms underlying the stem cell's innate capacity to adapt to mechanical stimuli as well as the role of mechanoadaptation in lineage commitment. An understanding of stem cell mechanoadaptation is key to deciphering lineage commitment, during prenatal development, postnatal wound healing, and engineering of tissues.

  7. A combined approach for the assessment of cell viability and cell functionality of human fibrochondrocytes for use in tissue engineering.

    Directory of Open Access Journals (Sweden)

    Ingrid Garzón

    Full Text Available Temporo-mandibular joint disc disorders are highly prevalent in adult populations. Autologous chondrocyte implantation is a well-established method for the treatment of several chondral defects. However, very few studies have been carried out using human fibrous chondrocytes from the temporo-mandibular joint (TMJ. One of the main drawbacks associated to chondrocyte cell culture is the possibility that chondrocyte cells kept in culture tend to de-differentiate and to lose cell viability under in in-vitro conditions. In this work, we have isolated human temporo-mandibular joint fibrochondrocytes (TMJF from human disc and we have used a highly-sensitive technique to determine cell viability, cell proliferation and gene expression of nine consecutive cell passages to determine the most appropriate cell passage for use in tissue engineering and future clinical use. Our results revealed that the most potentially viable and functional cell passages were P5-P6, in which an adequate equilibrium between cell viability and the capability to synthesize all major extracellular matrix components exists. The combined action of pro-apoptotic (TRAF5, PHLDA1 and anti-apoptotic genes (SON, HTT, FAIM2 may explain the differential cell viability levels that we found in this study. These results suggest that TMJF should be used at P5-P6 for cell therapy protocols.

  8. Cell Surface and Membrane Engineering: Emerging Technologies and Applications

    Directory of Open Access Journals (Sweden)

    Christopher T. Saeui

    2015-06-01

    Full Text Available Membranes constitute the interface between the basic unit of life—a single cell—and the outside environment and thus in many ways comprise the ultimate “functional biomaterial”. To perform the many and often conflicting functions required in this role, for example to partition intracellular contents from the outside environment while maintaining rapid intake of nutrients and efflux of waste products, biological membranes have evolved tremendous complexity and versatility. This article describes how membranes, mainly in the context of living cells, are increasingly being manipulated for practical purposes with drug discovery, biofuels, and biosensors providing specific, illustrative examples. Attention is also given to biology-inspired, but completely synthetic, membrane-based technologies that are being enabled by emerging methods such as bio-3D printers. The diverse set of applications covered in this article are intended to illustrate how these versatile technologies—as they rapidly mature—hold tremendous promise to benefit human health in numerous ways ranging from the development of new medicines to sensitive and cost-effective environmental monitoring for pathogens and pollutants to replacing hydrocarbon-based fossil fuels.

  9. HRSA Data Fact Sheets

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Health Resources and Services Administration (HRSA) Data Fact Sheets provide summary data about HRSA’s activities in each Congressional District, County, State,...

  10. Respirator Fact Sheet

    Science.gov (United States)

    ... have expiration dates that should be checked before purchase. Also, over time your mask can get old ... Respirator Fact Sheet [PDF - 706 KB] Follow NIOSH Facebook Flickr Pinterest Twitter YouTube NIOSH Homepage NIOSH A- ...

  11. Implementing High Performance Lexical Analyzer using CELL Broadband Engine Processor

    Directory of Open Access Journals (Sweden)

    P.J.SATHISH KUMAR

    2011-09-01

    Full Text Available The lexical analyzer is the first phase of the compiler and commonly the most time consuming. The compilation of large programs is still far from optimized in today’s compilers. With modern processors moving more towards improving parallelization and multithreading, it has become impossible for performance gains in older compilersas technology advances. Any multicore architecture relies on improving parallelism than on improving single core performance. A compiler that is completely parallel and optimized is yet to be developed and would require significant effort to create. On careful analysis we find that the performance of a compiler is majorly affected by the lexical analyzer’s scanning and tokenizing phases. This effort is directed towards the creation of a completelyparallelized lexical analyzer designed to run on the Cell/B.E. processor that utilizes its multicore functionalities to achieve high performance gains in a compiler. Each SPE reads a block of data from the input and tokenizes them independently. To prevent dependence of SPE’s, a scheme for dynamically extending static block-limits isincorporated. Each SPE is given a range which it initially scans and then finalizes its input buffer to a set of complete tokens from the range dynamically. This ensures parallelization of the SPE’s independently and dynamically, with the PPE scheduling load for each SPE. The initially static assignment of the code blocks is made dynamic as soon as one SPE commits. This aids SPE load distribution and balancing. The PPE maintains the output buffer until all SPE’s of a single stage commit and move to the next stage before being written out to the file, to maintain order of execution. The approach can be extended easily to other multicore architectures as well. Tokenization is performed by high-speed string searching, with the keyword dictionary of the language, using Aho-Corasick algorithm.

  12. Exploiting bacterial peptide display technology to engineer biomaterials for neural stem cell culture.

    Science.gov (United States)

    Little, Lauren E; Dane, Karen Y; Daugherty, Patrick S; Healy, Kevin E; Schaffer, David V

    2011-02-01

    Stem cells are often cultured on substrates that present extracellular matrix (ECM) proteins; however, the heterogeneous and poorly defined nature of ECM proteins presents challenges both for basic biological investigation of cell-matrix investigations and translational applications of stem cells. Therefore, fully synthetic, defined materials conjugated with bioactive ligands, such as adhesive peptides, are preferable for stem cell biology and engineering. However, identifying novel ligands that engage cellular receptors can be challenging, and we have thus developed a high throughput approach to identify new adhesive ligands. We selected an unbiased bacterial peptide display library for the ability to bind adult neural stem cells (NSCs), and 44 bacterial clones expressing peptides were identified and found to bind to NSCs with high avidity. Of these clones, four contained RGD motifs commonly found in integrin binding domains, and three exhibited homology to ECM proteins. Three peptide clones were chosen for further analysis, and their synthetic analogs were adsorbed on tissue culture polystyrene (TCPS) or grafted onto an interpenetrating polymer network (IPN) for cell culture. These three peptides were found to support neural stem cell self-renewal in defined medium as well as multi-lineage differentiation. Therefore, bacterial peptide display offers unique advantages to isolate bioactive peptides from large, unbiased libraries for applications in biomaterials engineering.

  13. Regenerative potential of human airway stem cells in lung epithelial engineering.

    Science.gov (United States)

    Gilpin, Sarah E; Charest, Jonathan M; Ren, Xi; Tapias, Luis F; Wu, Tong; Evangelista-Leite, Daniele; Mathisen, Douglas J; Ott, Harald C

    2016-11-01

    Bio-engineered organs for transplantation may ultimately provide a personalized solution for end-stage organ failure, without the risk of rejection. Building upon the process of whole organ perfusion decellularization, we aimed to develop novel, translational methods for the recellularization and regeneration of transplantable lung constructs. We first isolated a proliferative KRT5(+)TP63(+) basal epithelial stem cell population from human lung tissue and demonstrated expansion capacity in conventional 2D culture. We then repopulated acellular rat scaffolds in ex vivo whole organ culture and observed continued cell proliferation, in combination with primary pulmonary endothelial cells. To show clinical scalability, and to test the regenerative capacity of the basal cell population in a human context, we then recellularized and cultured isolated human lung scaffolds under biomimetic conditions. Analysis of the regenerated tissue constructs confirmed cell viability and sustained metabolic activity over 7 days of culture. Tissue analysis revealed extensive recellularization with organized tissue architecture and morphology, and preserved basal epithelial cell phenotype. The recellularized lung constructs displayed dynamic compliance and rudimentary gas exchange capacity. Our results underline the regenerative potential of patient-derived human airway stem cells in lung tissue engineering. We anticipate these advances to have clinically relevant implications for whole lung bioengineering and ex vivo organ repair.

  14. Municipal Solid Waste Gasification with Solid Oxide Fuel Cells and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    . The gasification process is usually based on an atmospheric - pressure circulating fluidized bed gasifier coupled to a tar - crac king vessel. Syngas can be used as fuel in different kind of power plant such as gas turbine cycle, steam cycle, combined cycle, internal and external combustion engine and Solid Oxide...... studied to optimize the plant efficiency in terms of operating conditions. Compared with modern waste incinerators with heat recovery, the gasification process integrated with SOFC and Stirling engine permits an increase in electricity output up of 50%, which means that the solid waste gasification...... Fuel Cell (SOFC). In the present study, a MSW gasification plant int egrated with SOFC is combined with a Stirling engine to recover the energy of the off - gases from the topping SOFC cycle. Detailed plant design is proposed and thermodynamic analysis is performed. Relevant parameters have been...

  15. Tissue-engineered graft constructed by self-derived cells and heterogeneous acellular matrix

    Institute of Scientific and Technical Information of China (English)

    HUANG Hui-min; WU Shao-feng; REN Hong

    2006-01-01

    Background: Endothelial and smooth muscle cells were used as seeding cells and heterogeneous acellularized matrix was used as scaffold to construct the tissue-engineered graft. Methods: A 2 weeks piglet was selected as a donor of seeding cells. Two-centimetre length of common carotid artery was dissected. Endothelial cells and smooth muscle cells were harvested by trypsin and collagenase digestion respectively. The isolated cells were cultured and expanded using routine cell culture technique.An adult sheep was used as a donor of acellularized matrix. The thoracic aorta was harvested and processed by a multi-step decellularizing technique to remove the original cells and preserve the elastic and collagen fibers. The cultured smooth muscle cells and endothelial cells were then seeded to the acellularized matrix and incubated in vitro for another 2 weeks. The cell seeded graft was then transplanted to the cell-donated piglet to substitute part of the native pulmonary artery. Results: The cultured cells from piglet were characterized as endothelial cells by the presence of specific antigens vWF and CD31, and smooth muscle cells by the presence of specific antigen α-actin on the cell surface respectively with immunohistochemical technique. After decellularizing processing for the thoracic aorta from sheep, all the cellular components were extracted and elastic and collagen fibers kept their original morphology and structure. The maximal load of acellular matrix was decreased and 20% lower than that of untreated thoracic aorta, but the maximal tensions between them were not different statistically and they had similar load-tension curves. Three months after transplantation, the animal was sacrificed and the graft was removed for observation. The results showed that the inner surfaces of the graft were smooth, without thrombosis and calcification. Under microscopy, a great number of growing cells could be seen and elastic and collagen fibers were abundant. Conclusion

  16. 2013 social balance sheet

    OpenAIRE

    Pierrette Heuse

    2014-01-01

    The transposition into national law of Directive 2013/34/EU on the annual financial statements of companies, expected by no later than July 2015, could alter the statistical obligations on small firms in connection with the filing of their annual accounts. In any case, the social balance sheet can no longer form an integral part of their accounts. Nevertheless, it contains original information whose usefulness is highlighted, on the basis of the social balance sheets for 2012, by examining th...

  17. Energy information sheets

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  18. The 3D printing of gelatin methacrylamide cell-laden tissue-engineered constructs with high cell viability.

    Science.gov (United States)

    Billiet, Thomas; Gevaert, Elien; De Schryver, Thomas; Cornelissen, Maria; Dubruel, Peter

    2014-01-01

    In the present study, we report on the combined efforts of material chemistry, engineering and biology as a systemic approach for the fabrication of high viability 3D printed macroporous gelatin methacrylamide constructs. First, we propose the use and optimization of VA-086 as a photo-initiator with enhanced biocompatibility compared to the conventional Irgacure 2959. Second, a parametric study on the printing of gelatins was performed in order to characterize and compare construct architectures. Hereby, the influence of the hydrogel building block concentration, the printing temperature, the printing pressure, the printing speed, and the cell density were analyzed in depth. As a result, scaffolds could be designed having a 100% interconnected pore network in the gelatin concentration range of 10-20 w/v%. In the last part, the fabrication of cell-laden scaffolds was studied, whereby the application for tissue engineering was tested by encapsulation of the hepatocarcinoma cell line (HepG2). Printing pressure and needle shape was revealed to impact the overall cell viability. Mechanically stable cell-laden gelatin methacrylamide scaffolds with high cell viability (>97%) could be printed.

  19. CRISPR/Cas9-mediated genome engineering of CHO cell factories: Application and perspectives.

    Science.gov (United States)

    Lee, Jae Seong; Grav, Lise Marie; Lewis, Nathan E; Faustrup Kildegaard, Helene

    2015-07-01

    Chinese hamster ovary (CHO) cells are the most widely used production host for therapeutic proteins. With the recent emergence of CHO genome sequences, CHO cell line engineering has taken on a new aspect through targeted genome editing. The bacterial clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system enables rapid, easy and efficient engineering of mammalian genomes. It has a wide range of applications from modification of individual genes to genome-wide screening or regulation of genes. Facile genome editing using CRISPR/Cas9 empowers researchers in the CHO community to elucidate the mechanistic basis behind high level production of proteins and product quality attributes of interest. In this review, we describe the basis of CRISPR/Cas9-mediated genome editing and its application for development of next generation CHO cell factories while highlighting both future perspectives and challenges. As one of the main drivers for the CHO systems biology era, genome engineering with CRISPR/Cas9 will pave the way for rational design of CHO cell factories.

  20. Efficient CRISPR/Cas9-based Genome Engineering in Human Pluripotent Stem Cells

    Science.gov (United States)

    Kime, Cody; Mandegar, Mohammad A.; Srivastava, Deepak; Yamanaka, Shinya; Conklin, Bruce R.; Rand, Tim A.

    2016-01-01

    Human pluripotent stem cells (hPSCs) are rapidly emerging as a powerful tool for biomedical discovery. The advent of human induced pluripotent stem (hiPS) cells with human embryonic stem (hES) cell-like properties has led to hPSCs with disease-specific genetic backgrounds for in-vitro disease modeling, drug discovery, mechanistic and developmental studies. To fully realize this potential it will be necessary to modify the genome of hPSCs with precision and flexibility. Pioneering experiments utilizing site-specific double strand break (DSB)-mediated genome engineering tools, including Zinc Finger Nucleases (ZFNs) and Transcription Activator-Like Effector Nucleases (TALENs), have paved the way to genome engineering in previously recalcitrant systems such as hPSCs. However, these methods are technically cumbersome and require significant expertise, which limited adoption. A major recent advance involving the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) endonuclease has dramatically simplified the effort required for genome engineering and will likely be adopted widely as the most rapid and flexible system for genome editing in hPSCs. Herein, we describe commonly practiced methods for CRISPR endonuclease genomic editing of hPSCs to cell lines containing genomes altered by Insertion/Deletion (INDEL) mutagenesis or insertion of recombinant genomic DNA. PMID:26724721

  1. Tissue-engineered skin preserving the potential of epithelial cells to differentiate into hair after grafting.

    Science.gov (United States)

    Larouche, Danielle; Cuffley, Kristine; Paquet, Claudie; Germain, Lucie

    2011-03-01

    The aim of this study was to evaluate whether tissue-engineered skin produced in vitro was able to sustain growth of hair follicles in vitro and after grafting. Different tissues were designed. Dissociated newborn mouse keratinocytes or newborn mouse hair buds (HBs) were added onto dermal constructs consisting of a tissue-engineered cell-derived matrix elaborated from either newborn mouse or adult human fibroblasts cultured with ascorbic acid. After 7-21 days of maturation at the air-liquid interface, no hair was noticed in vitro. Epidermal differentiation was observed in all tissue-engineered skin. However, human fibroblast-derived tissue-engineered dermis (hD) promoted a thicker epidermis than mouse fibroblast-derived tissue-engineered dermis (mD). In association with mD, HBs developed epithelial cyst-like inclusions presenting outer root sheath-like attributes. In contrast, epidermoid cyst-like inclusions lined by a stratified squamous epithelium were present in tissues composed of HBs and hD. After grafting, pilo-sebaceous units formed and hair grew in skin elaborated from HBs cultured 10-26 days submerged in culture medium in association with mD. However, the number of normal hair follicles decreased with longer culture time. This hair-forming capacity after grafting was not observed in tissues composed of hD overlaid with HBs. These results demonstrate that epithelial stem cells can be kept in vitro in a permissive tissue-engineered dermal environment without losing their potential to induce hair growth after grafting.

  2. Lentivirally engineered dendritic cells activate AFP-specific T cells which inhibit hepatocellular carcinoma growth in vitro and in vivo.

    Science.gov (United States)

    Liu, Yang; Butterfield, Lisa H; Fu, Xiaohui; Song, Zhenshun; Zhang, Xiaoping; Lu, Chongde; Ding, Guanghui; Wu, Mengchao

    2011-07-01

    α-fetoprotein (AFP), a tumor-associated antigen for hepatocellular carcinoma (HCC), is an established biomarker for HCC. In this study, we created a lentivirus expressing the AFP antigen and investigated the anti-tumor activity of AFP-specific CD8+ T cells, with and without CD4+ T cells, which were activated by either AFP peptide-pulsed or Lenti-AFP-engineered Dendritic cells (DCs) in vitro and in vivo. AFP-specific T cells could efficiently kill HepG2 HCC cells, and produced IL-2, IFN-γ, TNF-α, perforin and granzyme B, with minimal production of IL-10 (a negative regulator of T cell activation). Both strategies activated AFP-specific T cells, but the lentiviral strategy was superior by several measures. Data also support an impact of CD4+ T cells in supporting anti-tumor activity. In vivo studies in a xenograft HCC tumor model also showed that AFP-specific T cells could markedly suppress HCC tumor formation and morbidity in tumor-bearing nude mice, as well as regulate serum levels of related cytokines and anti-tumor molecules. In parallel with human in vitro T cell cultures, the in vivo model demonstrated superior anti-tumor effects and Th1-skewing with Lenti-AFP-DCs. This study supports the superiority of a full-length antigen lentivirus-based DCs vaccine strategy over peptides, and provides new insight into the design of DCs-based vaccines.

  3. Scaffold Free Bio-orthogonal Assembly of 3-Dimensional Cardiac Tissue via Cell Surface Engineering

    Science.gov (United States)

    Rogozhnikov, Dmitry; O’Brien, Paul J.; Elahipanah, Sina; Yousaf, Muhammad N.

    2016-12-01

    There has been tremendous interest in constructing in vitro cardiac tissue for a range of fundamental studies of cardiac development and disease and as a commercial system to evaluate therapeutic drug discovery prioritization and toxicity. Although there has been progress towards studying 2-dimensional cardiac function in vitro, there remain challenging obstacles to generate rapid and efficient scaffold-free 3-dimensional multiple cell type co-culture cardiac tissue models. Herein, we develop a programmed rapid self-assembly strategy to induce specific and stable cell-cell contacts among multiple cell types found in heart tissue to generate 3D tissues through cell-surface engineering based on liposome delivery and fusion to display bio-orthogonal functional groups from cell membranes. We generate, for the first time, a scaffold free and stable self assembled 3 cell line co-culture 3D cardiac tissue model by assembling cardiomyocytes, endothelial cells and cardiac fibroblast cells via a rapid inter-cell click ligation process. We compare and analyze the function of the 3D cardiac tissue chips with 2D co-culture monolayers by assessing cardiac specific markers, electromechanical cell coupling, beating rates and evaluating drug toxicity.

  4. Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds.

    Science.gov (United States)

    Song, Min Jae; Dean, David; Knothe Tate, Melissa L

    2013-07-01

    Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to "map the mechanome", defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates.

  5. Mechanical Modulation of Nascent Stem Cell Lineage Commitment in Tissue Engineering Scaffolds

    Science.gov (United States)

    Song, Min Jae; Dean, David; Tate, Melissa L. Knothe

    2013-01-01

    Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to “map the mechanome”, defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. PMID:23660249

  6. Metabolic engineering of apoptosis in cultured animal cells: implications for the biotechnology industry.

    Science.gov (United States)

    Vives, Joaquim; Juanola, Sandra; Cairó, Jordi Joan; Gòdia, Francesc

    2003-04-01

    Animal cells have been widely used to obtain a wide range of products for human and animal healthcare applications. However, the extreme sensitivity of these cells in respect to changes experienced in their environment is evidenced by the activation of a gene-encoded program known as apoptosis, resulting in their death and destruction. From the bioprocess angle, losses in cell viability bring lower productivities and higher risks of product degradation. Consequently, many research efforts have been devoted to the development of apoptosis protective mechanisms, including the metabolic engineering of apoptosis pathways, that has proven effective in diminishing programmed cell death in a variety of biotechnological relevant cell lines. This review is focused especially in the encouraging initial results obtained with the over-expression of cloned anti-apoptosis genes, from both endogenous and viral origin interfering at mitochondrial and initiator caspases levels.

  7. Biomass gasification integrated with a solid oxide fuel cell and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks for electric......An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks...... for electricity production. Unreacted hydrocarbons remaining after the SOFC are burned in a catalytic burner, and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. Domestic hot water is used as a heat sink for the Stirling engine. A complete balance...... with the suggested input parameters. This optimum value is approximately 65%, which is a rather modest value for SOFC. In addition, introducing a methanator increases plant efficiency slightly. If SOFC operating temperature decreases due to new technology then plant efficiency will slightly be increased. Decreasing...

  8. Recent advances in developing molecular tools for targeted genome engineering of mammalian cells.

    Science.gov (United States)

    Lim, Kwang-il

    2015-01-01

    Various biological molecules naturally existing in diversified species including fungi, bacteria, and bacteriophage have functionalities for DNA binding and processing. The biological molecules have been recently actively engineered for use in customized genome editing of mammalian cells as the molecule-encoding DNA sequence information and the underlying mechanisms how the molecules work are unveiled. Excitingly, multiple novel methods based on the newly constructed artificial molecular tools have enabled modifications of specific endogenous genetic elements in the genome context at efficiencies that are much higher than that of the conventional homologous recombination based methods. This minireview introduces the most recently spotlighted molecular genome engineering tools with their key features and ongoing modifications for better performance. Such ongoing efforts have mainly focused on the removal of the inherent DNA sequence recognition rigidity from the original molecular platforms, the addition of newly tailored targeting functions into the engineered molecules, and the enhancement of their targeting specificity. Effective targeted genome engineering of mammalian cells will enable not only sophisticated genetic studies in the context of the genome, but also widely-applicable universal therapeutics based on the pinpointing and correction of the disease-causing genetic elements within the genome in the near future.

  9. Genetic engineering of cell lines using lentiviral vectors to achieve antibody secretion following encapsulated implantation.

    Science.gov (United States)

    Lathuilière, Aurélien; Bohrmann, Bernd; Kopetzki, Erhard; Schweitzer, Christoph; Jacobsen, Helmut; Moniatte, Marc; Aebischer, Patrick; Schneider, Bernard L

    2014-01-01

    The controlled delivery of antibodies by immunoisolated bioimplants containing genetically engineered cells is an attractive and safe approach for chronic treatments. To reach therapeutic antibody levels there is a need to generate renewable cell lines, which can long-term survive in macroencapsulation devices while maintaining high antibody specific productivity. Here we have developed a dual lentiviral vector strategy for the genetic engineering of cell lines compatible with macroencapsulation, using separate vectors encoding IgG light and heavy chains. We show that IgG expression level can be maximized as a function of vector dose and transgene ratio. This approach allows for the generation of stable populations of IgG-expressing C2C12 mouse myoblasts, and for the subsequent isolation of clones stably secreting high IgG levels. Moreover, we demonstrate that cell transduction using this lentiviral system leads to the production of a functional glycosylated antibody by myogenic cells. Subsequent implantation of antibody-secreting cells in a high-capacity macroencapsulation device enables continuous delivery of recombinant antibodies in the mouse subcutaneous tissue, leading to substantial levels of therapeutic IgG detectable in the plasma.

  10. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Alexander Röder

    2015-11-01

    Full Text Available The use of biopolymers as a three dimensional (3D support structure for cell growth is a leading tissue engineering approach in regenerative medicine. Achieving consistent cell seeding and uniform cell distribution throughout 3D scaffold culture in vitro is an ongoing challenge. Traditionally, 3D scaffolds are cultured within tissue culture plates to enable reproducible cell seeding and ease of culture media change. In this study, we compared two different well-plates with different surface properties to assess whether seeding efficiencies and cell growth on 3D scaffolds were affected. Cell attachment and growth of murine calvarial osteoblast (MC3T3-E1 cells within a melt-electrospun poly-ε-caprolactone scaffold were assessed when cultured in either “low-adhesive” non-treated or corona discharged-treated well-plates. Increased cell adhesion was observed on the scaffold placed in the surface treated culture plates compared to the scaffold in the non-treated plates 24 h after seeding, although it was not significant. However, higher cell metabolic activity was observed on the bases of all well-plates than on the scaffold, except for day 21, well metabolic activity was higher in the scaffold contained in non-treated plate than the base. These results indicate that there is no advantage in using non-treated plates to improve initial cell seeding in 3D polymeric tissue engineering scaffolds, however non-treated plates may provide an improved metabolic environment for long-term studies.

  11. Hepatic tissue engineering: from transplantation to customized cell-based liver directed therapies from the laboratory.

    Science.gov (United States)

    Fiegel, Henning C; Kaufmann, Peter M; Bruns, Helge; Kluth, Dietrich; Horch, Raymund E; Vacanti, Joseph P; Kneser, Ulrich

    2008-01-01

    Today, liver transplantation is still the only curative treatment for liver failure due to end-stages liver diseases. Donor organ shortage, high cost and the need of immunosuppressive medications are still the major limitations in the field of liver transplantation. Thus, alternative innovative cell-based liver directed therapies, e.g. liver tissue engineering, are under investigation with the aim, that in future an artificial liver tissue could be created and be used for the replacement of the liver function in patients. Using cells instead of organs in this setting should permit (i) expansion of cells in an in vitro phase, (ii) genetic or immunological manipulation of cells for transplantation, (iii) tissue typing and cryopreservation in a cell bank, and (iv) the ex vivo genetic modification of patient's own cells prior re-implantation. Function and differentiation of liver cells are influenced by the three-dimensional organ architecture. The use of polymeric matrices permits the three dimensional formation of a neo-tissue and specific stimulation by adequate modification of the matrix-surface which might be essential for appropriate differentiation of transplanted cells. Additionally, culturing hepatocytes on three dimensional matrices permits culture in a flow bioreactor system with increased function and survival of the cultured cells. Based on bioreactor technology, bioartificial liver devices (BAL) are developed for extracorporeal liver support. Although BALs improved clinical and metabolic conditions, increased patient survival rates have not been proven yet. For intra-corporeal liver replacement, a concept which combines Tissue Engineering using three-dimensional, highly porous matrices with cell transplantation could be useful. In such a concept, whole liver mass transplantation, long term engraftment and function as well as correction of a metabolic defect in animal models could be achieved with a principally reversible procedure. Future studies have to

  12. Application of genetically engineered microbial whole-cell biosensors for combined chemosensing.

    Science.gov (United States)

    He, Wei; Yuan, Sheng; Zhong, Wen-Hui; Siddikee, Md Ashaduzzaman; Dai, Chuan-Chao

    2016-02-01

    The progress of genetically engineered microbial whole-cell biosensors for chemosensing and monitoring has been developed in the last 20 years. Those biosensors respond to target chemicals and produce output signals, which offer a simple and alternative way of assessment approaches. As actual pollution caused by human activities usually contains a combination of different chemical substances, how to employ those biosensors to accurately detect real contaminant samples and evaluate biological effects of the combined chemicals has become a realistic object of environmental researches. In this review, we outlined different types of the recent method of genetically engineered microbial whole-cell biosensors for combined chemical evaluation, epitomized their detection performance, threshold, specificity, and application progress that have been achieved up to now. We also discussed the applicability and limitations of this biosensor technology and analyzed the optimum conditions for their environmental assessment in a combined way.

  13. Full-thickness tissue engineered skin constructed with autogenic bone marrow mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    HE LiJuan; PEI XueTao; NAN Xue; WANG YunFang; GUAN LiDong; BAI CiXian; SHI ShuangShuang; YUAN HongFeng; CHEN Lin; LIU DaQing

    2007-01-01

    To explore the feasibility of repairing clinical cutaneous deficiency, autogenic bone marrow mesenchymal stem cells (BMSCs) were isolated and differentiated into epidermal cells and fibroblasts in vitro supplemented with different inducing factors and biomaterials to construct functional tissueengineered skin. The results showed that after 72 h induction, BMSCs displayed morphologic changes such as typical epidermal cell arrangement, from spindle shape to round or oval; tonofibrils, melanosomes and keratohyaline granules were observed under a transmission electronic microscope. The differentiated cells expressed epidermal stem cell surface marker CK19 (59.66%±4.2%) and epidermal cells differentiation marker CK10. In addition, the induced epidermal cells acquired the anti-radiation capacity featured by lowered apoptosis following exposure to UVB. On the other hand, the collagen microfibrils deposition was noticed under a transmission electronic microscope after differentiating into dermis fibroblasts; RT-PCR identified collagen type Ⅰ mRNA expression in differentiated cells;radioimmunoassay detected the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8) (up to 115.06pg/mL and 0.84 ng/mL, respectively). Further in vivo implanting BMSCs with scaffold material shortened skin wound repair significantly. In one word, autogenic BMSCs have the potential to differentiate into epidermal cells and fibroblasts in vitro, and show clinical feasibility acting as epidermis-like and dermis-like seed cells in skin engineering.

  14. Adult mesenchymal stem cells for bone and cartilage engineering: effect of scaffold materials

    Directory of Open Access Journals (Sweden)

    A Gigante

    2009-08-01

    Full Text Available Bone marrow is a useful cell source for skeletal tissue engineering approaches. In vitro differentiation of marrow mesenchymal stem cells (MSCs to chondrocytes or osteoblasts can be induced by the addition of specific growth factors to the medium. The present study evaluated the behaviour of human MSCs cultured on various scaffolds to determine whether their differentiation can be induced by cell-matrix interactions. MSCs from bone marrow collected from the acetabulum during hip arthroplasty procedures were isolated by cell sorting, expanded and characterised by a flow cytometry system. Cells were grown on three different scaffolds (type I collagen, type I + II collagen and type I collagen + hydroxyapatite membranes and analysed by histochemistry, immunohistochemistry and spectrophotometry (cell proliferation, alkaline phosphatase activity at 15 and 30 days. Widely variable cell adhesion and proliferation was observed on the three scaffolds. MSCs grown on type I+II collagen differentiated to cells expressing chondrocyte markers, while those grown on type I collagen + hydroxyapatite differentiated into osteoblast-like cells. The study highlighted that human MSCs grown on different scaffold matrices may display different behaviours in terms of cell proliferation and phenotype expression without growth factor supplementation.

  15. Ketone isosteres of 2-N-acetamidosugars as substrates for metabolic cell surface engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hang, Howard C.; Bertozzi, Carolyn R.

    2000-08-22

    Novel chemical reactivity can be engendered on cell surfaces by the metabolic incorporation of unnatural sugars into cell surface glycoconjuagtes. 2-N-Acetamido sugars such as GalNAc and GlcNAc are abundant components of cell surface glycoconjugates, and hence attractive targets for metabolic cell surface engineering. Here we report (1) the synthesis of isosteric analogs bearing a ketone group in place of the N-acetamido group, and (2) evaluation of their metabolic incorporation into mammalian cell surface glycans. A ketone isostere of GalNAc was metabolized by CHO cells through the salvage pathway and delivered to O-linked glycoproteins on the cell surface. Its residence at the core position of O-linked glycans is suggested by studies with a-benzyl GalNAc, an inhibitor of O-linked oligosaccharide extension. A mutant CHO cell line lacking endogenous UDP-GalNAc demonstrated enhanced metabolism of the GalNAc analog, suggesting that competition with native intermediates might limits enzymatic transformation in mammalian cells. A ketone isostere of GlcNAc could not be detected on CHO or human cell surfaces after incubation. Thus, the enzymes in the GlcNAc salvage pathway might be less permissive of unnatural substrates than those comprising the GalNAc salvage pathway. Alternatively, high levels of endogenous GlcNAc derivatives might compete with the ketone isostere and prevent its incorporation into oligosaccharides.

  16. Molecular Engineering Combined with Cosensitization Leads to Record Photovoltaic Efficiency for Non-ruthenium Solar Cells.

    Science.gov (United States)

    Hill, Jonathan P

    2016-02-24

    Here comes the sun: By using a combined strategy of molecular engineering and cosensitization, impressively high Jsc and Voc values were achieved for porphyrin dyes, resulting in high photovoltaic efficiencies up to 11.5 %, a record for non-ruthenium dye-sensitized solar cells (DSSCs) with the I(-) /I3 (-) electrolyte. The results provide insight into furthering the development of efficient DSSCs through synergistically enhanced photovoltage and photocurrent.

  17. Engineering Cartilage

    Science.gov (United States)

    ... Research Matters NIH Research Matters March 3, 2014 Engineering Cartilage Artistic rendering of human stem cells on ... situations has been a major goal in tissue engineering. Cartilage contains water, collagen, proteoglycans, and chondrocytes. Collagens ...

  18. Matrix production and organization by endothelial colony forming cells in mechanically strained engineered tissue constructs.

    Directory of Open Access Journals (Sweden)

    Nicky de Jonge

    Full Text Available AIMS: Tissue engineering is an innovative method to restore cardiovascular tissue function by implanting either an in vitro cultured tissue or a degradable, mechanically functional scaffold that gradually transforms into a living neo-tissue by recruiting tissue forming cells at the site of implantation. Circulating endothelial colony forming cells (ECFCs are capable of differentiating into endothelial cells as well as a mesenchymal ECM-producing phenotype, undergoing Endothelial-to-Mesenchymal-transition (EndoMT. We investigated the potential of ECFCs to produce and organize ECM under the influence of static and cyclic mechanical strain, as well as stimulation with transforming growth factor β1 (TGFβ1. METHODS AND RESULTS: A fibrin-based 3D tissue model was used to simulate neo-tissue formation. Extracellular matrix organization was monitored using confocal laser-scanning microscopy. ECFCs produced collagen and also elastin, but did not form an organized matrix, except when cultured with TGFβ1 under static strain. Here, collagen was aligned more parallel to the strain direction, similar to Human Vena Saphena Cell-seeded controls. Priming ECFC with TGFβ1 before exposing them to strain led to more homogenous matrix production. CONCLUSIONS: Biochemical and mechanical cues can induce extracellular matrix formation by ECFCs in tissue models that mimic early tissue formation. Our findings suggest that priming with bioactives may be required to optimize neo-tissue development with ECFCs and has important consequences for the timing of stimuli applied to scaffold designs for both in vitro and in situ cardiovascular tissue engineering. The results obtained with ECFCs differ from those obtained with other cell sources, such as vena saphena-derived myofibroblasts, underlining the need for experimental models like ours to test novel cell sources for cardiovascular tissue engineering.

  19. Dynamic gene expression for metabolic engineering of mammalian cells in culture.

    Science.gov (United States)

    Le, Huong; Vishwanathan, Nandita; Kantardjieff, Anne; Doo, Inseok; Srienc, Michael; Zheng, Xiaolu; Somia, Nikunj; Hu, Wei-Shou

    2013-11-01

    Recombinant mammalian cells are the major hosts for the production of protein therapeutics. In addition to high expression of the product gene, a hyper-producer must also harbor superior phenotypic traits related to metabolism, protein secretion, and growth control. Introduction of genes endowing the relevant hyper-productivity traits is a strategy frequently used to enhance the productivity. Most of such cell engineering efforts have been performed using constitutive expression systems. However, cells respond to various environmental cues and cellular events dynamically according to cellular needs. The use of inducible systems allows for time dependent expression, but requires external manipulation. Ideally, a transgene's expression should be synchronous to the host cell's own rhythm, and at levels appropriate for the objective. To that end, we identified genes with different expression dynamics and intensity ranges using pooled transcriptome data. Their promoters may be used to drive the expression of the transgenes following the desired dynamics. We isolated the promoter of the Thioredoxin-interacting protein (Txnip) gene and demonstrated its capability to drive transgene expression in concert with cell growth. We further employed this Chinese hamster promoter to engineer dynamic expression of the mouse GLUT5 fructose transporter in Chinese hamster ovary (CHO) cells, enabling them to utilize sugar according to cellular needs rather than in excess as typically seen in culture. Thus, less lactate was produced, resulting in a better growth rate, prolonged culture duration, and higher product titer. This approach illustrates a novel concept in metabolic engineering which can potentially be used to achieve dynamic control of cellular behaviors for enhanced process characteristics.

  20. Smart Cancer Cell Targeting Imaging and Drug Delivery System by Systematically Engineering Periodic Mesoporous Organosilica Nanoparticles.

    Science.gov (United States)

    Lu, Nan; Tian, Ying; Tian, Wei; Huang, Peng; Liu, Ying; Tang, Yuxia; Wang, Chunyan; Wang, Shouju; Su, Yunyan; Zhang, Yunlei; Pan, Jing; Teng, Zhaogang; Lu, Guangming

    2016-02-10

    The integration of diagnosis and therapy into one nanoplatform, known as theranostics, has attracted increasing attention in the biomedical areas. Herein, we first present a cancer cell targeting imaging and drug delivery system based on engineered thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs). The PMOs are stably and selectively conjugated with near-infrared fluorescence (NIRF) dye Cyanine 5.5 (Cy5.5) and anti-Her2 affibody on the outer surfaces to endow them with excellent NIRF imaging and cancer targeting properties. Also, taking the advantage of the thioether-group-incorporated mesopores, the release of chemotherapy drug doxorubicin (DOX) loaded in the PMOs is responsive to the tumor-related molecule glutathione (GSH). The drug release percentage reaches 84.8% in 10 mM of GSH solution within 24 h, which is more than 2-fold higher than that without GSH. In addition, the drug release also exhibits pH-responsive, which reaches 53.6% at pH 5 and 31.7% at pH 7.4 within 24 h. Confocal laser scanning microscopy and flow cytometry analysis demonstrate that the PMOs-based theranostic platforms can efficiently target to and enter Her2 positive tumor cells. Thus, the smart imaging and drug delivery nanoplatforms induce high tumor cell growth inhibition. Meanwhile, the Cy5.5 conjugated PMOs perform great NIRF imaging ability, which could monitor the intracellular distribution, delivery and release of the chemotherapy drug. In addition, cell viability and histological assessments show the engineered PMOs have good biocompatibility, further encouraging the following biomedical applications. Over all, the systemically engineered PMOs can serve as a novel cancer cell targeting imaging and drug delivery platform with NIRF imaging, GSH and pH dual-responsive drug release, and high tumor cell targeting ability.

  1. Design, Engineering, and Construction of Photosynthetic Microbial Cell Factories for Renewable Solar Fuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Lindblad, Peter; Lindberg, Pia; Stensjoe, Karin (Photochemistry and Molecular Science, Dept. of Chemistry-Aangstroem Laboratory, Uppsala Univ., Uppsala (Sweden)), E-mail: Peter.Lindblad@kemi.uu.se; Oliveira, Paulo (Instituto de Biologia Molecular e Celular, Porto (Portugal)); Heidorn, Thorsten (Bioforsk-Norwegian Inst. for Agricultural and Environmental Research, Aas Oslo, (Norway))

    2012-03-15

    There is an urgent need to develop sustainable solutions to convert solar energy into energy carriers used in the society. In addition to solar cells generating electricity, there are several options to generate solar fuels. This paper outlines and discusses the design and engineering of photosynthetic microbial systems for the generation of renewable solar fuels, with a focus on cyanobacteria. Cyanobacteria are prokaryotic microorganisms with the same type of photosynthesis as higher plants. Native and engineered cyanobacteria have been used by us and others as model systems to examine, demonstrate, and develop photobiological H{sub 2} production. More recently, the production of carbon-containing solar fuels like ethanol, butanol, and isoprene have been demonstrated. We are using a synthetic biology approach to develop efficient photosynthetic microbial cell factories for direct generation of biofuels from solar energy. Present progress and advances in the design, engineering, and construction of such cyanobacterial cells for the generation of a portfolio of solar fuels, e.g., hydrogen, alcohols, and isoprene, are presented and discussed. Possibilities and challenges when introducing and using synthetic biology are highlighted

  2. Investigation of engineered bacterial adhesins for opportunity to interface cells with abiotic materials

    Science.gov (United States)

    Terrell, Jessica L.; Dong, Hong; Holthoff, Ellen L.; Small, Meagan C.; Sarkes, Deborah A.; Hurley, Margaret M.; Stratis-Cullum, Dimitra N.

    2016-05-01

    The convenience of cellular genetic engineering has afforded the power to build `smart' synthetic biological tools with novel applications. Here, we have explored opportunities to hybridize engineered cells with inorganic materials toward the development of 'living' device-compatible systems. Cellular structural biology is engineerable based on the ability to rewrite genetic code to generate recombinant, foreign, or even unnatural proteins. With this capability on the biological end, it should be possible to achieve superior abio-compatibility with the inorganic materials that compose current microfabricated technology. This work investigated the hair-like appendages of