WorldWideScience

Sample records for cell sheet engineering

  1. Fabrication of a thermoresponsive cell culture dish: a key technology for cell sheet tissue engineering

    OpenAIRE

    Jun Kobayashi and Teruo Okano

    2010-01-01

    This article reviews the properties and characterization of an intelligent thermoresponsive surface, which is a key technology for cell sheet-based tissue engineering. Intelligent thermoresponsive surfaces grafted with poly(N-isopropylacrylamide) exhibit hydrophilic/hydrophobic alteration in response to temperature change. Cultured cells are harvested on thermoresponsive cell culture dishes by decreasing the temperature without the use of digestive enzymes or chelating agents. Our group has d...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Temperature-responsive intelligent interfaces for biomolecular separation and cell sheet engineering.

    Science.gov (United States)

    Nagase, Kenichi; Kobayashi, Jun; Okano, Teruo

    2009-06-01

    Temperature-responsive intelligent surfaces, prepared by the modification of an interface with poly(N-isopropylacrylamide) and its derivatives, have been used for biomedical applications. Such surfaces exhibit temperature-responsive hydrophilic/hydrophobic alterations with external temperature changes, which, in turn, result in thermally modulated interactions with biomolecules and cells. In this review, we focus on the application of these intelligent surfaces to chromatographic separation and cell cultures. Chromatographic separations using several types of intelligent surfaces are mentioned briefly, and various effects related to the separation of bioactive compounds are discussed, including wettability, copolymer composition and graft polymer architecture. Similarly, we also summarize temperature-responsive cell culture substrates that allow the recovery of confluent cell monolayers as contiguous living cell sheets for tissue-engineering applications. The key factors in temperature-dependent cell adhesion/detachment control are discussed from the viewpoint of grafting temperature-responsive polymers, and new methodologies for effective cell sheet culturing and the construction of thick tissues are summarized. PMID:19324682

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Efficiently engineered cell sheet using a complex of polyethylenimine–alginate nanocomposites plus bone morphogenetic protein 2 gene to promote new bone formation

    Directory of Open Access Journals (Sweden)

    Jin H

    2014-05-01

    Full Text Available Han Jin,1 Kai Zhang,2 Chunyan Qiao,1 Anliang Yuan,1 Daowei Li,1 Liang Zhao,1 Ce Shi,1 Xiaowei Xu,1 Shilei Ni,1 Changyu Zheng,3 Xiaohua Liu,4 Bai Yang,2 Hongchen Sun11Department of Pathology, School of Stomatology, Jilin University, Changchun, People’s Republic of China; 2State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, People’s Republic of China; 3Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA; 4Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, Dallas, TX, USAAbstract: Regeneration of large bone defects is a common clinical problem. Recently, stem cell sheet has been an emerging strategy in bone tissue engineering. To enhance the osteogenic potential of stem cell sheet, we fabricated bone morphogenetic protein 2 (BMP-2 gene-engineered cell sheet using a complex of polyethylenimine–alginate (PEI–al nanocomposites plus human BMP-2 complementary(cDNA plasmid, and studied its osteogenesis in vitro and in vivo. PEI–al nanocomposites carrying BMP-2 gene could efficiently transfect bone marrow mesenchymal stem cells. The cell sheet was made by culturing the cells in medium containing vitamin C for 10 days. Assays on the cell culture showed that the genetically engineered cells released the BMP-2 for at least 14 days. The expression of osteogenesis-related gene was increased, which demonstrated that released BMP-2 could effectively induce the cell sheet osteogenic differentiation in vitro. To further test the osteogenic potential of the cell sheet in vivo, enhanced green fluorescent protein or BMP-2-producing cell sheets were treated on the cranial bone defects. The results indicated that the BMP-2-producing cell sheet group was more efficient than other groups in promoting bone formation in the defect area. Our results suggested that PEI

  9. Infused polymers for cell sheet release

    Science.gov (United States)

    Juthani, Nidhi; Howell, Caitlin; Ledoux, Haylea; Sotiri, Irini; Kelso, Susan; Kovalenko, Yevgen; Tajik, Amanda; Vu, Thy L.; Lin, Jennifer J.; Sutton, Amy; Aizenberg, Joanna

    2016-05-01

    Tissue engineering using whole, intact cell sheets has shown promise in many cell-based therapies. However, current systems for the growth and release of these sheets can be expensive to purchase or difficult to fabricate, hindering their widespread use. Here, we describe a new approach to cell sheet release surfaces based on silicone oil-infused polydimethylsiloxane. By coating the surfaces with a layer of fibronectin (FN), we were able to grow mesenchymal stem cells to densities comparable to those of tissue culture polystyrene controls (TCPS). Simple introduction of oil underneath an edge of the sheet caused it to separate from the substrate. Characterization of sheets post-transfer showed that they retain their FN layer and morphology, remain highly viable, and are able to grow and proliferate normally after transfer. We expect that this method of cell sheet growth and detachment may be useful for low-cost, flexible, and customizable production of cellular layers for tissue engineering.

  10. Scaffold Sheet Design Strategy for Soft Tissue Engineering

    OpenAIRE

    Liping Tang; Dipendra Gyawali; Yi Zhang; Paul Thevenot; Tran, Richard T.; Jian Yang

    2010-01-01

    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 shee...

  11. Surface Engineering in Sheet Metal Forming

    OpenAIRE

    Carlsson, Per

    2005-01-01

    In recent years, surface engineering techniques have been developed in order to improve the tribological performance in many industrial applications. In sheet metal forming processes, the usage of liquid lubricants can be decreased by using self lubricated tribo surfaces which will result in more environmentally friendly workshops. In the present work two different concepts, i.e. the deposition of thin organic coatings on the steel sheet and PVD coatings on the tool, have been evaluated. The ...

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

    Science.gov (United States)

    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.

  13. The Application of Sheet Technology in Cartilage Tissue Engineering.

    Science.gov (United States)

    Ge, Yang; Gong, Yi Yi; Xu, Zhiwei; Lu, Yanan; Fu, Wei

    2016-04-01

    Cartilage tissue engineering started to act as a promising, even essential alternative method in the process of cartilage repair and regeneration, considering adult avascular structure has very limited self-renewal capacity of cartilage tissue in adults and a bottle-neck existed in conventional surgical treatment methods. Recent progressions in tissue engineering realized the development of more feasible strategies to treat cartilage disorders. Of these strategies, cell sheet technology has shown great clinical potentials in the regenerative areas such as cornea and esophagus and is increasingly considered as a potential way to reconstruct cartilage tissues for its non-use of scaffolds and no destruction of matrix secreted by cultured cells. Acellular matrix sheet technologies utilized in cartilage tissue engineering, with a sandwich model, can ingeniously overcome the drawbacks that occurred in a conventional acellular block, where cells are often blocked from migrating because of the non-nanoporous structure. Electrospun-based sheets with nanostructures that mimic the natural cartilage matrix offer a level of control as well as manipulation and make them appealing and widely used in cartilage tissue engineering. In this review, we focus on the utilization of these novel and promising sheet technologies to construct cartilage tissues with practical and beneficial functions. PMID:26414455

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

    Institute of Scientific and Technical Information of China (English)

    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.

  15. Automatic fabrication of 3-dimensional tissues using cell sheet manipulator technique.

    Science.gov (United States)

    Kikuchi, Tetsutaro; Shimizu, Tatsuya; Wada, Masanori; Yamato, Masayuki; Okano, Teruo

    2014-03-01

    Automated manufacturing is a key for tissue-engineered therapeutic products to become common-place and economical. Here, we developed an automatic cell sheet stacking apparatus to fabricate 3-dimensional tissue-engineered constructs exploiting our cell sheet manipulator technique, where cell sheets harvested from temperature-responsive culture dishes are stacked into a multilayered cell sheet. By optimizing the stacking conditions and cell seeding conditions, the apparatus was eventually capable of reproducibly making five-layer human skeletal muscle myoblast (HSMM) sheets with a thickness of approximately 70-80 μm within 100 min. Histological sections and confocal topographies of the five-layer HSMM sheets revealed a stratified structure with no delamination. In cell counts using trypsinization, the live cell numbers in one-, three- and five-layer HSMM sheets were equivalent to the seeded cell numbers at 1 h after the stacking processes; however, after subsequent 5-day static cultures, the live cell numbers of the five-layered HSMM sheets decreased slightly, while one- and three-layer HSMM sheets maintained their live cell numbers. This suggests that there are thickness limitations in maintaining tissues in a static culture. We concluded that by combining our cell sheet manipulator technique and industrial robot technology we can create a secure, cost-effective manufacturing system able to produce tissue-engineered products from cell sheets. PMID:24370007

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

    Science.gov (United States)

    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.

  17. Cell sheet technology for regeneration of esophageal mucosa

    Institute of Scientific and Technical Information of China (English)

    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.

  18. Polymer microlenses for quantifying cell sheet mechanics.

    Science.gov (United States)

    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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...

  5. Cell sheet technology and its applications in corneal tissue engineering%细胞层片技术及其在角膜组织工程研究的应用

    Institute of Scientific and Technical Information of China (English)

    韦巧玲; 徐建江

    2011-01-01

    Cell sheet technology (CST) is based on the use of poly (N-isopropylacrylamide,PNIPAAm) ,which can be exhibit reversible hydration and dehydration of its polymer chains in response to temperature changes across the lower critical solution temperature (LCST) of 32 ℃. By reducing the incubation temperature to 20 ℃, all cultured cells are harvested as intact sheets along with their deposited extracellular matrix (ECM) due to the conversion of the grafted PIPAAm from hydrophobic to hydrophilic, as ECM remains present on the basal surface of the cell sheets,they can maintain cell viability and function as well as directly transplanted to tissue beds or even layered to create three-dimensional (3D) tissue-like structures without any scaffolds or sutures. The temperature-sensitive surfaces' preparation approaches,density, thickness, membrane additive ingredients and so on, all affect cell adhesion and proliferation. It can maintain cell viability and improve function by accelerating cell sheet detachment through changing the membrane compositions, density as well as types of graft substrate. With CST, cultured autologous/allogeneic corneal seed cells in vitro used as transplant sources can overcome the problems of immunorejection of transplanted tissues as well as donor organ shortages. So far, the cell sheet of limbal epithelium and autologous oral mucosal epithelium obtained by the CST have been successfully used in clinical graft for ocular surface reconstruction. Finally, There is an overview of preparations of temperatureresponsive surfaces, impacts of various factors that influenced cultured cells in vitro and clinical applications or clinically relevant animal experimentations of CST in corneal tissue engineering.%细胞层片技术(CST)以异内基丙烯酰胺(PNIPAAm)在低临界溶解温度(LCST)快速转变亲水相/疏水相为基础,通过调节细胞的培养温度获取连接紧密的活细胞片与细胞外基质.这种无创性方法获取的活细

  6. 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 ...

  7. 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

  8. A noninvasive transfer system for polarized renal tubule epithelial cell sheets using temperature-responsive culture dishes

    Directory of Open Access Journals (Sweden)

    Kushida A.

    2005-08-01

    Full Text Available We used temperature-responsive culture dishes onto which the temperature-responsive polymer, poly(Nisopropylacrylamide, was covalently grafted for tissue engineering. Confluent cells harvested as intact sheets from these surfaces by simple temperature reduction can be transferred to various surfaces including additional culture dishes, other cell sheets, and tissues. In order to examine the maintenance of cell polarity, Madin-Darby canine kidney cells and human primary renal proximal tubule epithelial cells which had developed apical-basal cell polarity in culture, were subjected to cell sheet transfer. This functional and structural cell polarity, which is susceptible to treatment with trypsin, was examined by immunohistochemistry and transmission electron microscopy. Using our cell-sheet method, the noninvasive transfer of these cell sheets retaining typical distributions of Na+/K+-ATPase, GLUT-1, SGLT-1, aquaporin-1, neutral endopeptidase and dipeptidylendopeptidase IV, could be achieved. The transferred cell sheets also developed numerous microvilli and tight junctions at the apical and lateral membranes, respectively. For biochemical analysis, immunoblotting of occludin, a transmembrane protein that composes tight junctions, was conducted and results confirmed that occludin remained intact after cell sheet transfer. This two-dimensional cell sheet manipulation method promises to be useful for tissue engineering as well as in the investigation of epithelial cell polarity.

  9. 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

  10. 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.

  11. Rapid fabricating technique for multi-layered human hepatic cell sheets by forceful contraction of the fibroblast monolayer.

    Directory of Open Access Journals (Sweden)

    Yusuke Sakai

    Full Text Available Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.

  12. 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...

  13. 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

  14. A Computer Algorithm For Engineering Off-Shell Multiplets With Four Supercharges On The World Sheet

    CERN Document Server

    Burghardt, K

    2012-01-01

    We present an adinkra-based computer algorithm implemented in a Mathematica code and use it in a limited demonstration of how to engineer off-shell, arbitrary N-extended world-sheet supermultiplets. Using one of the outputs from this algorithm, we present evidence for the unexpected discovery of a previously unknown 8 - 8 representation of N = 2 world sheet supersymmetry. As well, we uncover a menagerie of (p, q) = (3, 1) world sheet supermultiplets.

  15. 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.

  16. 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

  17. Flow sheeting software as a tool when teaching Chemical Engineering

    OpenAIRE

    Abbas, Asad

    2011-01-01

    The aim of this thesis is to design different chemical processes by using flow sheeting software and to show the usefulness of flow sheeting software as an educational tool. The industries studied are hydrogen, sulfur, nitric acid and ethylene glycol production and a model of drying technique is also included. Firstly, there is an introduction of chemcad as a tool when teaching chemical processes and explanation of each industry which is selected to design. Various production methods for each...

  18. 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

  19. 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,...

  20. 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、

  1. Sheet plastic filters for solar cells

    Science.gov (United States)

    Wizenick, R. J.

    1972-01-01

    Poly(vinylidene fluoride) (PVF) film protects solar cells on Mars surface from radiation and prevents degradation of solar cell surfaces by Martian dust storms. PVF films may replace glass or quartz windows on solar cell arrays used to generate power on earth.

  2. 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.

  3. 骨髓间充质干细胞膜片复合磷酸三钙陶瓷构建工程化骨组织的体内成骨研究%Engineering bone tissue using bone marrow mesenchymal stem cell sheet and β-tricalcium phosphate ceramic

    Institute of Scientific and Technical Information of China (English)

    马东洋; 马敬; 姜东红; 王剑锋

    2011-01-01

    Objective To investigate the feasibility of constructing bone tissue using bone marrow mesenchymal stem cell (BMSC) sheet and β-tricalcium phosphate ceramic (TCP).Methods We first harvested a cell sheet from rabbit BMSCs using a continuous culture method and a scraping technique.The cell sheet was then wraped around a cylinder of β-TCP.Finally,the constructs were implanted into the subcutaneous pockets of nude mice for in vivo experiments.Gross view and histological examinations were performed to evaluate the harvested specimens.Results The cell sheet,with an average thickness of 158 mm, was composed of multi-layered cells separated in the extracellular matrix.Six weeks after implantation, the new bone tissue was present both on the edge and at the center of the TCP in sheet-TCP group.A layer of woven bone formed in the cell-sheet group.In contrast, the TCP was filled only with fibrous tissue in the TCP group,without evidence of bone formation.Conclusion The study indicates that the combination of osteogenic BMSC sheet and β-TCP ceramic can engineer bone tissue and the engineered construct might be considered as a promising substitute for bone repair.%目的:探讨骨髓间充质千细胞膜片复合磷酸三钙支架材料构建组织工程骨的可行性.方法:将兔骨髓间充质干细胞高密度接种于普通培养皿,在成骨诱导条件下连续培养2周,获得细胞膜片,修剪成长方形,并由一端卷起包裹圆柱状的磷酸三钙材料.静置孵育24h后将构建物移植到裸鼠背部皮下.术后6周取材,进行大体观察、组织学检查、组织定量学分析.结果:所获骨髓间充质干细胞膜片有多层细胞组成,保留了细胞外基质.实验组在材料表面及其孔隙内有较多的骨质形成;单一材料组空隙内为纤维组织,未见骨或软骨样组织;单一膜片组见片状编织骨形成.结论:骨髓间充质干细胞膜片在体内具有良好的成骨能力,可作为细胞释放载体与磷酸三

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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. PMID:26150714

  9. The effect of the coumarin-like derivative osthole on the osteogenic properties of human periodontal ligament and jaw bone marrow mesenchymal stem cell sheets.

    Science.gov (United States)

    Gao, Li-Na; An, Ying; Lei, Ming; Li, Bei; Yang, Hao; Lu, Hong; Chen, Fa-Ming; Jin, Yan

    2013-12-01

    Cell sheet engineering is a scaffold-free delivery concept that has been shown to improve mesenchymal stem cell-mediated regeneration of injured or pathologically damaged periodontal tissues in preclinical studies and several clinical trials. However, the best strategy for cell sheet production remains to be identified. The aim of this study was to investigate the biological effects of osthole, a coumarin-like derivative extracted from Chinese herbs, on the cell sheet formation and osteogenic properties of human periodontal ligament stem cells (PDLSCs) and jaw bone marrow mesenchymal stem cells (JBMMSCs). Patient-matched PDLSCs and JBMMSCs were isolated, and an appropriate concentration of osthole for cell culture was screened for both cell types in terms of cell proliferation and alkaline phosphatase (ALP) activity. Next, the best mode of osthole stimulation for inducing the formation of sheets by each cell type was selected by evaluating the amount of their extracellular matrix (ECM) protein production as well as osteogenic-related gene expression. Furthermore, both PDLSC and JBMMSC sheets obtained from each optimized technique were transplanted subcutaneously into nude mice to evaluate their capacity for ectopic bone regeneration. The results revealed that 10(-5) m/L osthole significantly enhanced the proliferation of both PDLSCs and JBMMSCs (P osthole groups (P > 0.05). In addition, 10(-5) m/L osthole was the best concentration to promote the ALP activities of both cells (P osthole throughout the entire culture stage (10 days) for PDLSCs or at the early stage (first 3 days) for JBMMSCs was the most effective osthole administration mode for cell sheet formation (P osthole-mediated PDLSC and JBMMSC sheets formed more new bone than those obtained without osthole intervention (P osthole stimulation may enhance ECM production and positively affect cell behavior in cell sheet engineering. PMID:24095254

  10. Engineering the Polyketide Cell Factory

    DEFF Research Database (Denmark)

    Mølgaard, Louise

    cerevisiae. Both organisms have well-known genetic tools available for gene targeting and heterologous expression. It has been the aim to create a stable expression platform with all genes integrated in the genome. This has been achieved through the use of two advanced genetic engineering systems for A...... 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...... through the use of adaptive evolution, random mutagenesis and screening as well as metabolic engineering. Firstly, in silico guided metabolic engineering was used as a tool to direct metabolism towards higher levels of 6-MSA production in A. nidulans. 6-MSA was stably expressed in the A. nidulans genome...

  11. 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.

  12. 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

  13. 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.

  14. 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.

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

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. 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.

  18. Engineering Nanostructures by Decorating Magnetic Nanoparticles onto Graphene Oxide Sheets to Shield Electromagnetic Radiations.

    Science.gov (United States)

    Mural, Prasanna Kumar S; Pawar, Shital Patangrao; Jayanthi, Swetha; Madras, Giridhar; Sood, Ajay K; Bose, Suryasarathi

    2015-08-01

    In this study, a minimum reflection loss of -70 dB was achieved for a 6 mm thick shield (at 17.1 GHz frequency) employing a unique approach. This was accomplished by engineering nanostructures through decoration of magnetic nanoparticles (nickel, Ni) onto graphene oxide (GO) sheets. Enhanced electromagnetic (EM) shielding was derived by selectively localizing the nanoscopic particles in a specific phase of polyethylene (PE)/poly(ethylene oxide) (PEO) blends. By introduction of a conducting inclusion (like multiwall carbon nanotubes, MWNTs) together with the engineered nanostructures (nickel-decorated GO, GO-Ni), the shielding efficiency can be enhanced significantly in contrast to physically mixing the particles in the blends. For instance, the composites showed a shielding efficiency >25 dB for a combination of MWNTs (3 wt %) and Ni nanoparticles (52 wt %) in PE/PEO blends. However, similar shielding effectiveness could be achieved for a combination of MWNTs (3 wt %) and 10 vol % of GO-Ni where in the effective concentration of Ni was only 19 wt %. The GO-Ni sheets facilitated in an efficient charge transfer as manifested from high electrical conductivity in the blends besides enhancing the permeability in the blends. It is envisioned that GO is simultaneously reduced in the process of synthesizing GO-Ni, and this facilitated in efficient charge transfer between the neighboring CNTs. More interestingly, the blends with MWNTs/GO-Ni attenuated the incoming EM radiation mostly by absorption. This study opens new avenues in designing polyolefin-based lightweight shielding materials by engineering nanostructures for numerous applications. PMID:26176935

  19. 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.

  20. Engineering stem cell niches in bioreactors

    OpenAIRE

    2013-01-01

    Stem cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells and amniotic fluid stem cells have the potential to be expanded and differentiated into various cell types in the body. Efficient differentiation of stem cells with the desired tissue-specific function is critical for stem cell-based cell therapy, tissue engineering, drug discovery and disease modeling. Bioreactors provide a great platform to regulate the stem cell microenvironment, known as “ni...

  1. 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

  2. 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.

  3. In vivo vascularization of cell sheets provided better long-term tissue survival than injection of cell suspension.

    Science.gov (United States)

    Takeuchi, Ryohei; Kuruma, Yosuke; Sekine, Hidekazu; Dobashi, Izumi; Yamato, Masayuki; Umezu, Mitsuo; Shimizu, Tatsuya; Okano, Teruo

    2016-08-01

    Cell sheets have shown a remarkable ability for repairing damaged myocardium in clinical and preclinical studies. Although they demonstrate a high degree of viability as engrafted cells in vivo, the reason behind their survivability is unclear. In this study, the survival and vascularization of rat cardiac cell sheets transplanted in the subcutaneous tissue of athymic rats were investigated temporally. The cell sheets showed significantly higher survival than cell suspensions for up to 12 months, using an in vivo bioluminescence imaging system to detect luciferase-positive transplanted cells. Terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay also showed a smaller number of apoptotic cells in the cell sheets than in the cell suspensions at 1 day. Rapid vascular formation and maturation were observed inside the cell sheets using an in vivo imaging system. Leaky vessels appeared at 6 h, red blood cells flowing through functional vessels appeared at 12 h, and morphologically matured vessels appeared at 7 days. In addition, immunostaining of cell sheets with nerve/glial antigen-2 (NG2) showed that vessel maturity increased over time. Interestingly, these results correlated with the dynamics of cell sheet mRNA expression. Genes related to endothelial cells (ECs) proliferation, migration and vessel sprouting were highly expressed within 1 day, and genes related to pericyte recruitment and vessel maturation were highly expressed at 3 days or later. This suggested that the cell sheets could secrete appropriate angiogenic factors in a timely way after transplantation, and this ability might be a key reason for their high survival. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24470393

  4. Polycrystalline Silicon Sheets for Solar Cells by the Improved Spinning Method

    Science.gov (United States)

    Maeda, Y.; Yokoyama, T.; Hide, I.

    1984-01-01

    Cost reduction of silicon materials in the photovoltaic program of materials was examined. The current process of producing silicon sheets is based entirely on the conventional Czochralski ingot growth and wafering used in the semiconductor industry. The current technology cannot meet the cost reduction demands for producing low cost silicon sheets. Alternative sheet production processes such as unconventional crystallization are needed. The production of polycrystalline silicon sheets by unconventional ingot technology is the casting technique. Though large grain sheets were obtained by this technique, silicon ribbon growth overcomes deficiencies of the casting process by obtaining the sheet directly from the melt. The need to solve difficulties of growth stability and impurity effects are examined. The direct formation process of polycrystalline silicon sheets with large grain size, smooth surface, and sharp edges from the melt with a high growth rate which will yield low cost silicon sheets for solar cells and the photovoltaic characteristics associated with this type of sheet to include an EBIC study of the grain boundaries are described.

  5. Cryopreservation of Cell Sheets of Adipose Stem Cells: Limitations and Successes

    OpenAIRE

    Prata, F. P.; M.T. Cerqueira; Moreira-Silva, J.; Pirraco, Rogério P.; Reis, R. L.; Marques, A.P.

    2014-01-01

    Cell Sheets of hASCs (hASCs-CS) have been previously proposed for wound healing applications(1, 2) and despite the concern for production time reduction, the possibility of having these hASCs-CS off-the-shelf is appealing. The goal of this work was to define a cryopreservation methodology allowing to preserve cells viability and the properties CS matrix. hASCs-CS obtained from three different donors were created in UP-cell thermoresponsive dishes(Nunc, Germany) as previously reported(1,...

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

    OpenAIRE

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

    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 d...

  7. Engineering Stem Cells for Biomedical Applications.

    Science.gov (United States)

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

    2016-01-01

    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.

  8. 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.

  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 cells in bone tissue engineering

    International Nuclear Information System (INIS)

    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)

  11. 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)

  12. 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.

  13. 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...

  14. 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

  15. 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.

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

    Science.gov (United States)

    Wang, Zhongshan; Wu, Guangsheng; Wei, Mengying; Liu, Qian; Zhou, Jian; Qin, Tian; Feng, Xiaoke; Liu, Huan; Feng, Zhihong; Zhao, Yimin

    2016-01-01

    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 reverse transfection approach, and miR-21 delivery significantly enhanced the in vitro osteogenic differentiation of hBMMSC sheets in terms of upregulating calcification-related gene expression and enhancing alkaline phosphatase production, collagen secretion, and mineralized nodule formation. The enhanced osteogenic activity of hBMMSC sheets might promisingly lead to more rapid and more robust bone regeneration for clinical use. PMID:27274237

  17. 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.

  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. 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...

  20. Cancer Immunotherapy Using Engineered Hematopoietic Stem Cells

    OpenAIRE

    Gschweng, Eric Hans

    2015-01-01

    Engineering the immune system against cancer ideally provides surgical precision against the antigen bearing target cell while avoiding the systemic, off-target toxicity of chemotherapy. Successful treatment of patients in the clinic has been achieved by the expression of anti-cancer T-cell receptors (TCR) and chimeric antigen receptors (CAR) in T cells followed by infusion of these cells into cancer patients. Unfortunately, while many patients initially respond showing anti-tumor efficacy, t...

  1. 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...

  2. Glycan Engineering for Cell and Developmental Biology

    Science.gov (United States)

    Griffin, Matthew E.; Hsieh-Wilson, Linda C.

    2016-01-01

    Cell-surface glycans are a diverse class of macromolecules that participate in many key biological processes, including cell-cell communication, development, and disease progression. Thus, the ability to modulate the structures of glycans on cell surfaces provides a powerful means not only to understand fundamental processes but also to direct activity and elicit desired cellular responses. Here, we describe methods to sculpt glycans on cell surfaces and highlight recent successes in which artificially engineered glycans have been employed to control biological outcomes such as the immune response and stem cell fate. PMID:26933739

  3. 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

  4. 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.

  5. The PLUTO reactor at Harwell, U.K. and ancillary hot cell facilities. Information sheets

    International Nuclear Information System (INIS)

    Technical information is given on the PLUTO reactor and associated hot cell facilities, with the main emphasis on experimental irradiation facilities and specialized irradiation devices (loops and capsules). The information is presented in the form of five information sheets under the headings; main characteristics of the reactor; utilization and specialization of the reactor; experimental facilities; neutron spectra; main characteristics of specialized irradiation devices

  6. πSPIM: high NA high resolution isotropic light-sheet imaging in cell culture dishes.

    Science.gov (United States)

    Theer, Patrick; Dragneva, Denitsa; Knop, Michael

    2016-01-01

    Light-sheet fluorescence microscopy (LSFM), also termed single plane illumination microscopy (SPIM), enables live cell fluorescence imaging with optical sectioning capabilities superior to confocal microscopy and without any out-of-focus exposure of the specimen. However, the need of two objective lenses, one for light-sheet illumination and one for imaging, imposes geometrical constraints that require LSFM setups to be adapted to the specific needs of different types of specimen in order to obtain optimal imaging conditions. Here we demonstrate the use of an oblique light-sheet configuration adapted to provide the highest possible Gaussian beam enabled resolution in LSFM. The oblique light-sheet configuration furthermore enables LSFM imaging at the surface of a cover slip, without the need of specific sample mounting. In addition, the system is compatible with simultaneous high NA wide-field epi-fluorescence imaging of the specimen contained in a glass-bottom cell culture dish. This prevents cumbersome sample mounting and enables rapid screening of large areas of the specimen followed by high-resolution LSFM imaging of selected cells. We demonstrate the application of this microscope for in toto imaging of endocytosis in yeast, showing for the first time imaging of all endocytic events of a given cell over a period of >5 minutes with sub-second resolution. PMID:27619647

  7. Engineering Hematopoietic Stem Cells: Lessons from Development.

    Science.gov (United States)

    Rowe, R Grant; Mandelbaum, Joseph; Zon, Leonard I; Daley, George Q

    2016-06-01

    Cell engineering has brought us tantalizingly close to the goal of deriving patient-specific hematopoietic stem cells (HSCs). While directed differentiation and transcription factor-mediated conversion strategies have generated progenitor cells with multilineage potential, to date, therapy-grade engineered HSCs remain elusive due to insufficient long-term self-renewal and inadequate differentiated progeny functionality. A cross-species approach involving zebrafish and mammalian systems offers complementary methodologies to improve understanding of native HSCs. Here, we discuss the role of conserved developmental timing processes in vertebrate hematopoiesis, highlighting how identification and manipulation of stage-specific factors that specify HSC developmental state must be harnessed to engineer HSCs for therapy. PMID:27257760

  8. 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

  9. NREL Spurred the Success of Multijunction Solar Cells (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-08-01

    Many scientists once believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. However, researchers at the National Renewable Energy Laboratory (NREL) thought differently, and they employed GaInP in a material combination that allowed the multijunction cell to flourish. The multijunction cell is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic products.

  10. Engineered Models of Confined Cell Migration.

    Science.gov (United States)

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

    2016-07-11

    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

  11. Allogeneic Transplantation of Periodontal Ligament-Derived Multipotent Mesenchymal Stromal Cell Sheets in Canine Critical-Size Supra-Alveolar Periodontal Defect Model.

    Science.gov (United States)

    Tsumanuma, Yuka; Iwata, Takanori; Kinoshita, Atsuhiro; Washio, Kaoru; Yoshida, Toshiyuki; Yamada, Azusa; Takagi, Ryo; Yamato, Masayuki; Okano, Teruo; Izumi, Yuichi

    2016-01-01

    Periodontitis is a chronic inflammatory disease that induces the destruction of tooth-supporting tissues, followed by tooth loss. Although several approaches have been applied to periodontal regeneration, complete periodontal regeneration has not been accomplished. Tissue engineering using a combination of cells and scaffolds is considered to be a viable alternative strategy. We have shown that autologous transplantation of periodontal ligament-derived multipotent mesenchymal stromal cell (PDL-MSC) sheets regenerates periodontal tissue in canine models. However, the indications for autologous cell transplantation in clinical situations are limited. Therefore, this study evaluated the safety and efficacy of allogeneic transplantation of PDL-MSC sheets using a canine horizontal periodontal defect model. Canine PDL-MSCs were labeled with enhanced green fluorescent protein (EGFP) and were cultured on temperature-responsive dishes. Three-layered cell sheets were transplanted around denuded root surfaces either autologously or allogeneically. A mixture of β-tricalcium phosphate and collagen gel was placed on the bone defects. Eight weeks after transplantation, dogs were euthanized and subjected to microcomputed tomography and histological analyses. RNA and DNA were extracted from the paraffin sections to verify the presence of EGFP at the transplantation site. Inflammatory markers from peripheral blood sera were quantified using an enzyme-linked immunosorbent assay. Periodontal regeneration was observed in both the autologous and the allogeneic transplantation groups. The allogeneic transplantation group showed particularly significant regeneration of newly formed cementum, which is critical for the periodontal regeneration. Serum levels of inflammatory markers from peripheral blood sera showed little difference between the autologous and allogeneic groups. EGFP amplicons were detectable in the paraffin sections of the allogeneic group. These results suggest that

  12. 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.

  13. 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).

  14. THE ENGINEERING GEOLOGY OF THE SIDMOUTH DISTRICT 1:50000 GEOLOGICAL SHEET 326/340

    OpenAIRE

    Forster, A

    1998-01-01

    This description ofthe engineering geology ofthe district around Sidmouth (Fig. 1) was based on the lithostratigraphical units shown in Table 1. They may be subject to amendment as the remapping proceeds. The account also includes information from a geotechnical database compiled by the Coastal and Engineering Geology Group of the BGS.

  15. Cell-Free Metabolic Engineering: Biomanufacturing beyond the cell

    OpenAIRE

    Dudley, Quentin M.; Karim, Ashty S.; Jewett, Michael C.

    2014-01-01

    Industrial biotechnology and microbial metabolic engineering are poised to help meet the growing demand for sustainable, low-cost commodity chemicals and natural products, yet the fraction of biochemicals amenable to commercial production remains limited. Common problems afflicting the current state-of-the-art include low volumetric productivities, build-up of toxic intermediates or products, and byproduct losses via competing pathways. To overcome these limitations, cell-free metabolic engin...

  16. 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.

  17. 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

    2016-07-22

    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. PMID:27284690

  18. 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.

  19. 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

  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. Lumped series resistance of solar cells as a result of distributed sheet resistance

    Science.gov (United States)

    Sokolić, Saša; Križaj, Dejan; Amon, Slavko

    1993-04-01

    An analysis of solar cell distributed sheet resistance is performed by solving the nonlinear Poisson equation for the surface potential. Two different approaches to lumped series resistance are discussed: equivalent series resistance RSeq obtained from the cell's equivalent circuit that satisfies the actual current of the cell (all other parameters in the equivalent circuit except the series resistance are kept constant) and Joule series resistance RSJ obtained from the Joule losses in the emitter of the cell. It is observed that the I( U) characteristic obtained from the equivalent circuit that includes RSJ generally disagrees with the actual I( U) characteristic of the solar cell. An additional series resistance RSadd should be introduced in series with RSJ. Series resistances RSJ, Sadd and RSeq are analyzed numerically in one and two dimensions for different conditions of terminal voltage, illumination and weighted sheet resistance Rshb2, where b is related to the geometry of the analyzed cell. Following the derivations and the results of the numerical analysis it can be concluded that wherever RSJ varies as a function of terminal voltage, RSadd should be taken into consideration.

  3. Fabrication of mouse embryonic stem cell-derived layered cardiac cell sheets using a bioreactor culture system.

    Directory of Open Access Journals (Sweden)

    Katsuhisa Matsuura

    Full Text Available Bioengineered functional cardiac tissue is expected to contribute to the repair of injured heart tissue. We previously developed cardiac cell sheets using mouse embryonic stem (mES cell-derived cardiomyocytes, a system to generate an appropriate number of cardiomyocytes derived from ES cells and the underlying mechanisms remain elusive. In the present study, we established a cultivation system with suitable conditions for expansion and cardiac differentiation of mES cells by embryoid body formation using a three-dimensional bioreactor. Daily conventional medium exchanges failed to prevent lactate accumulation and pH decreases in the medium, which led to insufficient cell expansion and cardiac differentiation. Conversely, a continuous perfusion system maintained the lactate concentration and pH stability as well as increased the cell number by up to 300-fold of the seeding cell number and promoted cardiac differentiation after 10 days of differentiation. After a further 8 days of cultivation together with a purification step, around 1 × 10(8 cardiomyocytes were collected in a 1-L bioreactor culture, and additional treatment with noggin and granulocyte colony stimulating factor increased the number of cardiomyocytes to around 5.5 × 10(8. Co-culture of mES cell-derived cardiomyocytes with an appropriate number of primary cultured fibroblasts on temperature-responsive culture dishes enabled the formation of cardiac cell sheets and created layered-dense cardiac tissue. These findings suggest that this bioreactor system with appropriate medium might be capable of preparing cardiomyocytes for cell sheet-based cardiac tissue.

  4. High-efficiency cell concepts on low-cost silicon sheets

    Science.gov (United States)

    Bell, R. O.; Ravi, K. V.

    1985-01-01

    The limitations on sheet growth material in terms of the defect structure and minority carrier lifetime are discussed. The effect of various defects on performance are estimated. Given these limitations designs for a sheet growth cell that will make the best of the material characteristics are proposed. Achievement of optimum synergy between base material quality and device processing variables is proposed. A strong coupling exists between material quality and the variables during crystal growth, and device processing variables. Two objectives are outlined: (1) optimization of the coupling for maximum performance at minimal cost; and (2) decoupling of materials from processing by improvement in base material quality to make it less sensitive to processing variables.

  5. Pupil engineering to create sheets, lines, and multiple spots at the focal region

    International Nuclear Information System (INIS)

    In this paper we present several algorithms to find pupil functions which give focal fields with different desirable properties, such as a laterally elongated spot, a focal sheet, a spot with increased axial resolution, a lateral array of closely packed spots, and a lateral array of widely spaced diffraction-limited spots. All the algorithms work by writing the pupil function as a linear combination of appropriate basis functions, for which the coefficients are optimized. The focal field can be calculated repeatedly efficiently, since focal fields of each of the basis functions are precalculated. For each of the desired focal fields, the specific details of the algorithm are explained, simulation results are presented, and the results are compared to those in other publications. (paper)

  6. 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. PMID:27375939

  7. [Study progress of dental pulp stem cells in tissue engineering].

    Science.gov (United States)

    Shiyu, Shi; Jiamin, Xie

    2015-12-01

    In recent years, modern tissue engineering is becoming emerging and developing rapidly, and the acquisition, cultivation and differentiation of seed cells is the premise and foundation of the construction of tissue engineering, so more and more scholars pay attention to stem cells as seed cells for tissue engineering construction. Dental pulp stem cells (DPSCs) is a kind of adult stem cells derived from dental pulp, and as a new kind of seed cells of tissue engineering, the study of DPSCs presents important significance in tissue and organ regeneration. In this review, we introduced the progress of studies on dental pulp stem cells and discussed their clinical application prospects. PMID:27051964

  8. Light sheet microscopy for tracking single molecules on the apical surface of living cells.

    Science.gov (United States)

    Li, Yu; Hu, Ying; Cang, Hu

    2013-12-12

    Single particle tracking is a powerful tool to study single molecule dynamics in living biological samples. However, current tracking techniques, which are based mainly on epifluorescence, confocal, or TIRF microscopy, have difficulties in tracking single molecules on the apical surface of a cell. We present here a three-dimensional (3D) single particle tracking technique that is based on prism coupled light-sheet microscopy (PCLSM). This novel design provides a signal-to-noise ratio comparable to confocal microscopy while it has the capability of illuminating at arbitrary depth. We demonstrate tracking of single EGF molcules on the apical surface of live cell membranes from their binding to EGF receptors until they are internalized or photobleached. We found that EGF exhibits multiple diffusion behaviors on live A549 cell membranes. At room temperature, the average diffusion coefficient of EGF on A549 cells was measured to be 0.13 μm(2)/s. Depletion of cellular cholesterol with methyl-β-cyclodextrin leads to a broader distribution of diffusion coefficients and an increase of the average diffusion coefficient at room temperature. This light-sheet based 3D single particle tracking technique solves the technique difficulty of tracking single particles on apical membranes and is able to document the whole "lifetime" of a particle from binding till photobleaching or internalization. PMID:23895420

  9. 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.

  10. 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.

  11. Cell-free metabolic engineering: Biomanufacturing beyond the cell

    Energy Technology Data Exchange (ETDEWEB)

    Dudley, QM; Karim, AS; Jewett, MC

    2014-10-15

    Industrial biotechnology and microbial metabolic engineering are poised to help meet the growing demand for sustainable, low-cost commodity chemicals and natural products, yet the fraction of biochemicals amenable to commercial production remains limited. Common problems afflicting the current state-of-the-art include low volumetric productivities, build-up of toxic intermediates or products, and byproduct losses via competing pathways. To overcome these limitations, cell-free metabolic engineering (CFME) is expanding the scope of the traditional bioengineering model by using in vitro ensembles of catalytic proteins prepared from purified enzymes or crude lysates of cells for the production of target products. In recent years, the unprecedented level of control and freedom of design, relative to in vivo systems, has inspired the development of engineering foundations for cell-free systems. These efforts have led to activation of long enzymatic pathways (>8 enzymes), near theoretical conversion yields, productivities greater than 100 mg L-1 h(-1), reaction scales of >100 L, and new directions in protein purification, spatial organization, and enzyme stability. In the coming years, CFME will offer exciting opportunities to: (i) debug and optimize biosynthetic pathways; (ii) carry out design-build-test iterations without re-engineering organisms; and (iii) perform molecular transformations when bioconversion yields, productivities, or cellular toxicity limit commercial feasibility.

  12. 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.

  13. Evaluation of the ion implantation process for production of solar cells from silicon sheet materials

    Science.gov (United States)

    Spitzer, M. B.

    1983-01-01

    The objective of this program is the investigation and evaluation of the capabilities of the ion implantation process for the production of photovoltaic cells from a variety of present-day, state-of-the-art, low-cost silicon sheet materials. Task 1 of the program concerns application of ion implantation and furnace annealing to fabrication of cells made from dendritic web silicon. Task 2 comprises the application of ion implantation and pulsed electron beam annealing (PEBA) to cells made from SEMIX, SILSO, heat-exchanger-method (HEM), edge-defined film-fed growth (EFG) and Czochralski (CZ) silicon. The goals of Task 1 comprise an investigation of implantation and anneal processes applied to dendritic web. A further goal is the evaluation of surface passivation and back surface reflector formation. In this way, processes yielding the very highest efficiency can be evaluated. Task 2 seeks to evaluate the use of PEBA for various sheet materials. A comparison of PEBA to thermal annealing will be made for a variety of ion implantation processes.

  14. 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.

  15. Engineering CAR-T Cells: Design Concepts

    Science.gov (United States)

    Srivastava, Shivani; Riddell, Stanley R.

    2016-01-01

    Despite being empirically designed based on a simple understanding of TCR signaling, T cells engineered with chimeric antigen receptors (CARs) have been remarkably successful in treating patients with advanced refractory B cell malignancies. However, many challenges remain in improving the safety and efficacy of this therapy and extending it toward the treatment of epithelial cancers. Other aspects TCR signaling beyond those directly provided by CD3ζ and CD28 phosphorylation strongly influence a T cell’s ability to differentiate and acquire full effector functions. Here, we discuss how the principles of TCR recognition, including spatial constraints, Kon/Koff rates, and synapse formation, along with in-depth analysis of CAR signaling might be applied to develop safer and more effective synthetic tumor targeting receptors. PMID:26169254

  16. Deformable Graph Model for Tracking Epithelial Cell Sheets in Fluorescence Microscopy.

    Science.gov (United States)

    Zou, Roger S; Tomasi, Carlo

    2016-07-01

    We propose a novel method for tracking cells that are connected through a visible network of membrane junctions. Tissues of this form are common in epithelial cell sheets and resemble planar graphs where each face corresponds to a cell. We leverage this structure and develop a method to track the entire tissue as a deformable graph. This coupled model in which vertices inform the optimal placement of edges and vice versa captures global relationships between tissue components and leads to accurate and robust cell tracking. We compare the performance of our method with that of four reference tracking algorithms on four data sets that present unique tracking challenges. Our method exhibits consistently superior performance in tracking all cells accurately over all image frames, and is robust over a wide range of image intensity and cell shape profiles. This may be an important tool for characterizing tissues of this type especially in the field of developmental biology where automated cell analysis can help elucidate the mechanisms behind controlled cell-shape changes. PMID:26829784

  17. 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.

  18. 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.

  19. Better Solar Cells and Manufacturing Processes Using NREL's Ultrafast Quantum Efficiency Method (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-08-01

    Fact sheet on the FlashQE system, a 2011 R&D 100 Award winner. A solid-state optical system by NREL and Tau Science measures solar cell quantum efficiency in less than a second, enabling a suite of new capabilities for solar cell manufacturers.

  20. Endochondral bone tissue engineering using embryonic stem cells

    OpenAIRE

    Jukes, Jojanneke M.; Both, Sanne Karijn; Leusink, Anouk; Sterk, Lotus M. Th.; Blitterswijk, van, W.J.; Boer, de, J.W.

    2008-01-01

    Embryonic stem cells can provide an unlimited supply of pluripotent cells for tissue engineering applications. Bone tissue engineering by directly differentiating ES cells (ESCs) into osteoblasts has been unsuccessful so far. Therefore, we investigated an alternative approach, based on the process of endochondral ossification. A cartilage matrix was formed in vitro by mouse ESCs seeded on a scaffold. When these cartilage tissue-engineered constructs (CTECs) were implanted s.c., the cartilage ...

  1. Induced Pluripotent Stem Cells for Neural Tissue Engineering

    OpenAIRE

    Wang, Aijun; Tang, Zhenyu; Park, In-Hyun; Zhu, Yiqian; Patel, Shyam; Daley, George Q.; Song, Li

    2011-01-01

    Induced pluripotent stem cells (iPSCs) hold great promise for cell therapies and tissue engineering. Neural crest stem cells (NCSCs) are multipotent and represent a valuable system to investigate iPSC differentiation and therapeutic potential. Here we derived NCSCs from human iPSCs and embryonic stem cells (ESCs), and investigated the potential of NCSCs for neural tissue engineering. The differentiation of iPSCs and the expansion of derived NCSCs varied in different cell lines, but all NCSC l...

  2. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    Science.gov (United States)

    Barthes, Julien; Özçelik, Hayriye; Hindié, Mathilde; Ndreu-Halili, Albana; Hasan, Anwarul

    2014-01-01

    In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells' behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future. PMID:25143954

  3. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    Directory of Open Access Journals (Sweden)

    Julien Barthes

    2014-01-01

    Full Text Available In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells’ behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future.

  4. 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.

  5. 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.

  6. Cell-Based Strategies for Meniscus Tissue Engineering

    OpenAIRE

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

    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 ...

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

    Science.gov (United States)

    Pangesty, Azizah Intan; Arahira, Takaaki; Todo, Mitsugu

    2016-01-01

    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. PMID:27271675

  8. 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.

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

    Science.gov (United States)

    Pangesty, Azizah Intan; Arahira, Takaaki; Todo, Mitsugu

    2016-01-01

    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. PMID:27271675

  10. 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.

  11. 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

  12. 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.

  13. Autologous transplantation of oral mucosal epithelial cell sheets cultured on an amniotic membrane substrate for intraoral mucosal defects.

    Directory of Open Access Journals (Sweden)

    Takeshi Amemiya

    Full Text Available The human amniotic membrane (AM is a thin intrauterine placental membrane that is highly biocompatible and possesses anti-inflammatory and anti-scarring properties. Using AM, we developed a novel method for cultivating oral mucosal epithelial cell sheets. We investigated the autologous transplantation of oral mucosal epithelial cells cultured on AM in patients undergoing oral surgeries. We obtained specimens of AM from women undergoing cesarean sections. This study included five patients without any history of a medical disorder who underwent autologous cultured oral epithelial transplantation following oral surgical procedures. Using oral mucosal biopsy specimens obtained from these patients, we cultured oral epithelial cells on an AM carrier. We transplanted the resultant cell sheets onto the oral mucosal defects. Patients were followed-up for at least 12 months after transplantation. After 2-3 weeks of being cultured on AM, epithelial cells were well differentiated and had stratified into five to seven layers. Immunohistochemistry revealed that the cultured cells expressed highly specific mucosal epithelial cell markers and basement membrane proteins. After the surgical procedures, no infection, bleeding, rejection, or sheet detachment occurred at the reconstructed sites, at which new oral mucous membranes were evident. No recurrence was observed in the long-term follow-up, and the postoperative course was excellent. Our results suggest that AM-cultured oral mucosal epithelial cell sheets represent a useful biomaterial and feasible method for oral mucosal reconstruction. However, our primary clinical study only evaluated their effects on a limited number of small oral mucosal defects.

  14. Engineering spinal fusion: evaluating ceramic materials for cell based tissue engineered approaches

    NARCIS (Netherlands)

    Wilson, C.E.

    2011-01-01

    The principal aim of this thesis was to advance the development of tissue engineered posterolateral spinal fusion by investigating the potential of calcium phosphate ceramic materials to support cell based tissue engineered bone formation. This was accomplished by developing several novel model syst

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

    Science.gov (United States)

    Silvestri, Ludovico; Paciscopi, Marco; Soda, Paolo; Biamonte, Filippo; Iannello, Giulio; Frasconi, Paolo; Pavone, Francesco S

    2015-01-01

    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 (PCs) 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 PCs 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 PCs. 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 PCs, 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 PCs 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. PMID:26074783

  16. 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.

  17. 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…

  18. 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…

  19. Engineering models and methods for industrial cell control

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1997-01-01

    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...... SHIPYARD.It is concluded that cell control technology provides for increased performance in production systems, and that the Cell Control Engineering concept reduces the effort for providing and operating high quality and high functionality cell control solutions for the industry....... 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...

  20. 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.

  1. 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...

  2. Comparison of Osteogenesis between Adipose-Derived Mesenchymal Stem Cells and Their Sheets on Poly-ε-Caprolactone/β-Tricalcium Phosphate Composite Scaffolds in Canine Bone Defects.

    Science.gov (United States)

    Kim, Yongsun; Lee, Seung Hoon; Kang, Byung-Jae; Kim, Wan Hee; Yun, Hui-Suk; Kweon, Oh-Kyeong

    2016-01-01

    Multipotent mesenchymal stem cells (MSCs) and MSC sheets have effective potentials of bone regeneration. Composite polymer/ceramic scaffolds such as poly-ε-caprolactone (PCL)/β-tricalcium phosphate (β-TCP) are widely used to repair large bone defects. The present study investigated the in vitro osteogenic potential of canine adipose-derived MSCs (Ad-MSCs) and Ad-MSC sheets. Composite PCL/β-TCP scaffolds seeded with Ad-MSCs or wrapped with osteogenic Ad-MSC sheets (OCS) were also fabricated and their osteogenic potential was assessed following transplantation into critical-sized bone defects in dogs. The alkaline phosphatase (ALP) activity of osteogenic Ad-MSCs (O-MSCs) and OCS was significantly higher than that of undifferentiated Ad-MSCs (U-MSCs). The ALP, runt-related transcription factor 2, osteopontin, and bone morphogenetic protein 7 mRNA levels were upregulated in O-MSCs and OCS as compared to U-MSCs. In a segmental bone defect, the amount of newly formed bone was greater in PCL/β-TCP/OCS and PCL/β-TCP/O-MSCs/OCS than in the other groups. The OCS exhibit strong osteogenic capacity, and OCS combined with a PCL/β-TCP composite scaffold stimulated new bone formation in a critical-sized bone defect. These results suggest that the PCL/β-TCP/OCS composite has potential clinical applications in bone regeneration and can be used as an alternative treatment modality in bone tissue engineering. PMID:27610141

  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. 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.

  5. 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.

  6. 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)

  7. Assembly of cells and vesicles for organ engineering

    Science.gov (United States)

    Taguchi, Tetsushi

    2011-12-01

    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.

  8. Can engineered "designer" T cells outsmart chronic hepatitis B?

    Science.gov (United States)

    Protzer, U; Abken, H

    2010-01-01

    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. PMID:21188203

  9. Neural tissue engineering using embryonic and induced pluripotent stem cells

    OpenAIRE

    Willerth, Stephanie M.

    2011-01-01

    With the recent start of the first clinical trial evaluating a human embryonic stem cell-derived therapy for the treatment of acute spinal cord injury, it is important to review the current literature examining the use of embryonic stem cells for neural tissue engineering applications with a focus on diseases and disorders that affect the central nervous system. Embryonic stem cells exhibit pluripotency and thus can differentiate into any cell type found in the body, including those found in ...

  10. Cell Processing Engineering for Regenerative Medicine : Noninvasive Cell Quality Estimation and Automatic Cell Processing.

    Science.gov (United States)

    Takagi, Mutsumi

    2016-01-01

    The cell processing engineering including automatic cell processing and noninvasive cell quality estimation of adherent mammalian cells for regenerative medicine was reviewed. Automatic cell processing necessary for the industrialization of regenerative medicine was introduced. The cell quality such as cell heterogeneity should be noninvasively estimated before transplantation to patient, because cultured cells are usually not homogeneous but heterogeneous and most protocols of regenerative medicine are autologous system. The differentiation level could be estimated by two-dimensional cell morphology analysis using a conventional phase-contrast microscope. The phase-shifting laser microscope (PLM) could determine laser phase shift at all pixel in a view, which is caused by the transmitted laser through cell, and might be more noninvasive and more useful than the atomic force microscope and digital holographic microscope. The noninvasive determination of the laser phase shift of a cell using a PLM was carried out to determine the three-dimensional cell morphology and estimate the cell cycle phase of each adhesive cell and the mean proliferation activity of a cell population. The noninvasive discrimination of cancer cells from normal cells by measuring the phase shift was performed based on the difference in cytoskeleton density. Chemical analysis of the culture supernatant was also useful to estimate the differentiation level of a cell population. A probe beam, an infrared beam, and Raman spectroscopy are useful for diagnosing the viability, apoptosis, and differentiation of each adhesive cell. PMID:25373455

  11. 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.

  12. 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. PMID:27138532

  13. 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. PMID:19929819

  14. Air intake and exhaust systems in fuel cell engines

    Energy Technology Data Exchange (ETDEWEB)

    Fuesser, R.; Weber, O. [Mann and Hummel (Germany)

    1999-07-01

    This paper describes the design and development of the air intake and exhaust system of a fuel cell powered road vehicle. In this instance the automotive supplier designed both the air intake and the exhaust system. The fuel cell engine gives a cold combustion effect making it possible to manufacture the exhaust from plastic materials. (UK)

  15. 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...

  16. Vectorized Data Processing on the Cell Broadband Engine

    NARCIS (Netherlands)

    Héman, S.; Nes, N.J.; Zukowski, M.; Boncz, P.A.

    2007-01-01

    In this work, we research the suitability of the Cell Broadband Engine for database processing. We start by outlining the main architectural features of Cell and use microbenchmarks to characterize the latency and throughput of its memory infrastructure. Then, we discuss the challenges of porting RD

  17. Biodiesel Basics (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-06-01

    This fact sheet provides a brief introduction to biodiesel, including a discussion of biodiesel blends, which blends are best for which vehicles, where to buy biodiesel, how biodiesel compares to diesel fuel in terms of performance, how biodiesel performs in cold weather, whether biodiesel use will plug vehicle filters, how long-term biodiesel use may affect engines, biodiesel fuel standards, and whether biodiesel burns cleaner than diesel fuel. The fact sheet also dismisses the use of vegetable oil as a motor fuel.

  18. 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.

  19. Cell interactions in bone tissue engineering

    OpenAIRE

    Pirraco, Rogério; Marques, A. P.; Reis, R. L.

    2010-01-01

    Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and...

  20. Cell interactions in bone tissue engineering

    OpenAIRE

    Pirraco, R. P.; Marques, A. P.; Reis, R. L.

    2009-01-01

    Abstract Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and...

  1. 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.

  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. 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.

  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. 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.

  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. Solar cell as a self-oscillating heat engine

    International Nuclear Information System (INIS)

    Solar cells are engines converting energy supplied by the photon flux into work. All known types of macroscopic engines and turbines are also self-oscillating systems which yield a periodic motion at the expense of a usually non-periodic source of energy. The very definition of work in the formalism of quantum open systems suggests the hypothesis that the oscillating ‘piston’ is a necessary ingredient of the work extraction process. This aspect of solar cell operation is absent in the existing descriptions and the main goal of this paper is to show that plasma oscillations provide the physical implementation of a piston. (paper)

  8. 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.

  9. Thermoresponsive polyurethane/siloxane membrane for wound dressing and cell sheet transplantation: In-vitro and in-vivo studies.

    Science.gov (United States)

    Rezapour-Lactoee, Alireza; Yeganeh, Hamid; Ostad, Seyed Nasser; Gharibi, Reza; Mazaheri, Zohreh; Ai, Jafar

    2016-12-01

    Polyurethane/siloxane based wound dressing for transferring fibroblast cell sheet to wounded skin and ability to provide an optimum condition for cellular activity at damaged tissue was prepared in this research. The dressing was made thermoresponsive, via the introduction of a poly(N-isopropyl acrylamide) copolymer into the backbone of dressing. The ability of membrane for adhesion, growth, and proliferation of fibroblast cells was improved via surface modification with gelatin. The optimized dressing exhibited appropriate tensile strength (4.5MPa) and elongation at break (80%) to protect wound against physical forces. Due to controlled equilibrium water absorption of about 89% and water vapor transmission rate of 2040g/m(2)day, the dressing could maintain the favorable moist environment over moderate to high exuding wounds. The grown cell sheet on dressing membrane could easily roll up from the surface just with lowering the temperature. The in vivo study of the wound dressed with cell loaded membrane confirmed the accelerated healing and production of tissue with complete re-epithelization, enhanced vascularization, and increased collagen deposition on the damaged area. PMID:27612775

  10. Continuous synthesis of graphene sheets by spray pyrolysis and their use as catalysts for fuel cells.

    Science.gov (United States)

    Zou, Biao; Wang, Xiao Xia; Huang, Xin Xin; Wang, Jian Nong

    2015-01-14

    Graphene sheets (GNS) were synthesized continuously by spray pyrolysis of iron carbonyl and pyridine. The Pt catalyst supported on GNS exhibited excellent durability for oxygen reduction reaction (ORR). The GNS, when used as a metal-free catalyst for ORR, showed performance even better than the commercial Pt/C catalyst. PMID:25421428

  11. 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.

  12. New model for cardiomyocyte sheet transplantation using avirus-cell fusion technique

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    AIM To facilitate close contacts between transplantedcardiomyocytes and host skeletal muscle using cellfusion mediated by hemagglutinating virus of Japanenvelope (HVJ-E) and tissue maceration.METHODS: Cardiomyocytes (1.5 × 106) from fetalrats were first cultured. After proliferation, some cellswere used for fusion with adult muscle fibers usingHVJ-E. Other cells were used to create cardiomyocytesheets (area: about 3.5 cm2 including 2.1 × 106cells), which were then treated with Nile blue, separated,and transplanted between the latissimusdorsi and intercostal muscles of adult rats with fourcombinations of HVJ-E and/or NaOH maceration:G1: HVJ-E(+), NaOH(+), Cardiomyocytes(+); G2:HVJ-E(-), NaOH(+), Cardiomyocytes(+); G3: HVJ-E(+),NaOH(-), Cardiomyocytes(+); G4: HVJ-E(-), NaOH(-),Cardiomyocytes(-). At 1 and 2 wk after transplantation,the four groups were compared by detection of beatingdomains, motion images using moving target analysissoftware, action potentials, gene expression of MLC-2v and Mesp1 by reverse transcription-polymerasechain reaction, hematoxylin-eosin staining, and immunostainingfor cardiac troponin and skeletal myosin.RESULTS: In vitro cardiomyocytes were fused withskeletal muscle fibers using HVJ-E. Cardiomyocytesheets remained in the primary transplanted sites for2 wk. Although beating domains were detected inG1, G2, and G3 rats, G1 rats prevailed in the number,size, motion image amplitudes, and action potentialcompared with G2 and G3 rats. Close contacts wereonly found in G1 rats. At 1 wk after transplantation,the cardiomyocyte sheets showed adhesion at variouspoints to the myoblast layer in the latissimus dorsimuscle. At 2 wk after transplantation, close contactswere seen over a broad area. Part of the skeletalmuscle sarcoplasma seemed to project into themyocardiocyte plasma and some nuclei appeared toshare both sarcoplasmas.CONCLUSION: The present results

  13. Engineered Biomaterials to Enhance Stem Cell-Based Cardiac Tissue Engineering and Therapy.

    Science.gov (United States)

    Hasan, Anwarul; Waters, Renae; Roula, Boustany; Dana, Rahbani; Yara, Seif; Alexandre, Toubia; Paul, Arghya

    2016-07-01

    Cardiovascular disease is a leading cause of death worldwide. Since adult cardiac cells are limited in their proliferation, cardiac tissue with dead or damaged cardiac cells downstream of the occluded vessel does not regenerate after myocardial infarction. The cardiac tissue is then replaced with nonfunctional fibrotic scar tissue rather than new cardiac cells, which leaves the heart weak. The limited proliferation ability of host cardiac cells has motivated investigators to research the potential cardiac regenerative ability of stem cells. Considerable progress has been made in this endeavor. However, the optimum type of stem cells along with the most suitable matrix-material and cellular microenvironmental cues are yet to be identified or agreed upon. This review presents an overview of various types of biofunctional materials and biomaterial matrices, which in combination with stem cells, have shown promises for cardiac tissue replacement and reinforcement. Engineered biomaterials also have applications in cardiac tissue engineering, in which tissue constructs are developed in vitro by combining stem cells and biomaterial scaffolds for drug screening or eventual implantation. This review highlights the benefits of using biomaterials in conjunction with stem cells to repair damaged myocardium and give a brief description of the properties of these biomaterials that make them such valuable tools to the field. PMID:26953627

  14. Prospect of Stem Cells in Bone Tissue Engineering: A Review

    Directory of Open Access Journals (Sweden)

    Azizeh-Mitra Yousefi

    2016-01-01

    Full Text Available Mesenchymal stem cells (MSCs have been the subject of many studies in recent years, ranging from basic science that looks into MSCs properties to studies that aim for developing bioengineered tissues and organs. Adult bone marrow-derived mesenchymal stem cells (BM-MSCs have been the focus of most studies due to the inherent potential of these cells to differentiate into various cell types. Although, the discovery of induced pluripotent stem cells (iPSCs represents a paradigm shift in our understanding of cellular differentiation. These cells are another attractive stem cell source because of their ability to be reprogramed, allowing the generation of multiple cell types from a single cell. This paper briefly covers various types of stem cell sources that have been used for tissue engineering applications, with a focus on bone regeneration. Then, an overview of some recent studies making use of MSC-seeded 3D scaffold systems for bone tissue engineering has been presented. The emphasis has been placed on the reported scaffold properties that tend to improve MSCs adhesion, proliferation, and osteogenic differentiation outcomes.

  15. Engineered T Cells for the Adoptive Therapy of B-Cell Chronic Lymphocytic Leukaemia

    Directory of Open Access Journals (Sweden)

    Philipp Koehler

    2012-01-01

    Full Text Available B-cell chronic lymphocytic leukaemia (B-CLL remains an incurable disease due to the high risk of relapse, even after complete remission, raising the need to control and eliminate residual tumor cells in long term. Adoptive T cell therapy with genetically engineered specificity is thought to fulfil expectations, and clinical trials for the treatment of CLL are initiated. Cytolytic T cells from patients are redirected towards CLL cells by ex vivo engineering with a chimeric antigen receptor (CAR which binds to CD19 on CLL cells through an antibody-derived domain and triggers T cell activation through CD3ζ upon tumor cell engagement. Redirected T cells thereby target CLL cells in an MHC-unrestricted fashion, secret proinflammatory cytokines, and eliminate CD19+ leukaemia cells with high efficiency. Cytolysis of autologous CLL cells by patient's engineered T cells is effective, however, accompanied by lasting elimination of healthy CD19+ B-cells. In this paper we discuss the potential of the strategy in the treatment of CLL, the currently ongoing trials, and the future challenges in the adoptive therapy with CAR-engineered T cells.

  16. 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

  17. Tissue Engineering Bone Using Autologous Progenitor Cells in the Peritoneum

    OpenAIRE

    Jinhui Shen; Ashwin Nair; Ramesh Saxena; Cheng Cheng Zhang; Joseph Borrelli; Liping Tang

    2014-01-01

    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 periton...

  18. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali [Center for Biomedical Engineering, Department of Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA 02115 (United States); Jabbari, Esmaiel, E-mail: alik@rics.bwh.harvard.edu [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2011-05-27

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  19. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  20. 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.

  1. 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.

  2. 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.

  3. Upgrades of Hanford Engineering Development Laboratory hot cell facilities

    International Nuclear Information System (INIS)

    The Hanford Engineering Development Laboratory operates the 327 Postirradiation Testing Laboratory (PITL) and the 324 Shielded Materials Facility (SMF). These hot cell facilities provide diverse capabilities for the postirradiation examination and testing of irradiated reactor fuels and materials. The primary function of these facilities is to determine failure mechanisms and effects of irradiation on physical and mechanical properties of reactor components. The purpose of this paper is to review major equipment and facility upgrades that enhance customer satisfaction and broaden the engineering capabilities for more diversified programs. These facility and system upgrades are providing higher quality remote nondestructive and destructive examination services with increased productivity, operator comfort, and customer satisfaction

  4. Engineering a clinically-useful matrix for cell therapy.

    Science.gov (United States)

    Prestwich, Glenn D

    2008-01-01

    The design criteria for matrices for encapsulation of cells for cell therapy include chemical, biological, engineering, marketing, regulatory, and financial constraints. What is required is a biocompatible material for culture of cells in three-dimensions (3-D) that offers ease of use, experimental flexibility to alter composition and compliance, and a composition that would permit a seamless transition from in vitro to in vivo use. The challenge is to replicate the complexity of the native extracellular matrix (ECM) environment with the minimum number of components necessary to allow cells to rebuild a given tissue. Our approach is to deconstruct the ECM to a few modular components that can be reassembled into biomimetic materials that meet these criteria. These semi-synthetic ECMs (sECMs) employ thiol-modified derivatives of hyaluronic acid (HA) that can form covalently crosslinked, biodegradable hydrogels. These sECMs are "living" biopolymers, meaning that they can be crosslinked in the presence of cells or tissues to enable cell therapy and tissue engineering. Moreover, the sECMs allow inclusion of the appropriate biological cues needed to simulate the complexity of the ECM of a given tissue. Taken together, the sECM technology offers a manufacturable, highly reproducible, flexible, FDA-approvable, and affordable vehicle for cell expansion and differentiation in 3-D. PMID:19279714

  5. 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.

  6. 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.

  7. 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. PMID:26140302

  8. 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)

  9. 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.

  10. Automatic design system for a steel sheet pile cellular cofferdam and its evaluation; Koya ita cell shiki kozobutsu no kihon sekkei no jidoka oyobi system no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Y.; Ito, A.; Yokota, H. [Port and Harbour Research Inst., Kanagawa (Japan)

    1995-03-01

    A new design scheme has recently been introduced to a sheet pile cellular cofferdam, which takes the effect of the embedded part of a sheet pile on the structural stability into account. On the basis of the modification of the design way, the automatic design system for this type of structure has been established. Port engineers are able to conduct basic design of a breakwater and a seaward made of the sheet pile cellular cofferdam. Parametric studies have been conducted using this automatic design system. It has been confirmed based on the study that this system provides the reasonable structural sections, embedded length, and so on. Some particular characteristics of this type of structures have also been provided in this present report. 5 refs., 59 figs., 4 tabs.

  11. 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

    2015-02-01

    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.

  12. 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...

  13. Cell broadband engine architecture as a DSP platform

    Science.gov (United States)

    Szumski, Karol; Malanowski, Mateusz

    2009-06-01

    The slowing pace of performance improvement in the commonly available processors is a cause of concern amongst many computational scientists. This combined with the ever increasing need for computational power has caused us to turn to alternative architectures in search of performance gains. Two main candidates were the Compute Unified Device Architecture (CUDA) and the Cell Broadband Engine (CELL BE) architecture. This paper focuses on the latter, outlining the architecture and basic programming paradigms, and also contains performance comparison of algorithms currently developed by our team.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Establishment of cell surface engineering and its development.

    Science.gov (United States)

    Ueda, Mitsuyoshi

    2016-07-01

    Cell surface display of proteins/peptides has been established based on mechanisms of localizing proteins to the cell surface. In contrast to conventional intracellular and extracellular (secretion) expression systems, this method, generally called an arming technology, is particularly effective when using yeasts as a host, because the control of protein folding that is often required for the preparation of proteins can be natural. This technology can be employed for basic and applied research purposes. In this review, I describe various strategies for the construction of engineered yeasts and provide an outline of the diverse applications of this technology to industrial processes such as the production of biofuels and chemicals, as well as bioremediation and health-related processes. Furthermore, this technology is suitable for novel protein engineering and directed evolution through high-throughput screening, because proteins/peptides displayed on the cell surface can be directly analyzed using intact cells without concentration and purification. Functional proteins/peptides with improved or novel functions can be created using this beneficial, powerful, and promising technique. PMID:27305282

  19. Dendritic cell and macrophage staining by monoclonal antibodies in tissue sections and epidermal sheets.

    OpenAIRE

    Flotte, T. J.; Springer, T A; Thorbecke, G. J.

    1983-01-01

    Mouse tissue sections were stained by monoclonal antibodies to macrophage antigens (Mac-1 (M1/70), Mac-2 (M3/38), Mac-3 (M3/84) with the use of immunoperoxidase. Mac-1 was located diffusely in the cytoplasm of round cells in a high percentage of alveolar macrophages, resident peritoneal and bone marrow cells, in splenic red pulp, and in rare perivascular cells in the thymus. Mac-1 was absent in epithelial cells and Langerhans cells. Mac-2 was strongly positive in many dendritic cells in the t...

  20. 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.

  1. 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 improvem......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....

  2. 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.

  3. Toward Synthetic Spatial Patterns in Engineered Cell Populations with Chemotaxis.

    Science.gov (United States)

    Duran-Nebreda, Salva; Solé, Ricard V

    2016-07-15

    A major force shaping form and patterns in biology is based in the presence of amplification mechanisms able to generate ordered, large-scale spatial structures out of local interactions and random initial conditions. Turing patterns are one of the best known candidates for such ordering dynamics, and their existence has been proven in both chemical and physical systems. Their relevance in biology, although strongly supported by indirect evidence, is still under discussion. Extensive modeling approaches have stemmed from Turing's pioneering ideas, but further confirmation from experimental biology is required. An alternative possibility is to engineer cells so that self-organized patterns emerge from local communication. Here we propose a potential synthetic design based on the interaction between population density and a diffusing signal, including also directed motion in the form of chemotaxis. The feasibility of engineering such a system and its implications for developmental biology are also assessed. PMID:27009520

  4. 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

  5. Advanced tendencies in development of photovoltaic cells for power engineering

    Science.gov (United States)

    Strebkov, D. S.

    2015-01-01

    Development of solar power engineering must be based on original innovative Russian and world technologies. It is necessary to develop promising Russian technologies of manufacturing of photovoltaic cells and semiconductor materials: chlorine-free technology for obtaining solar silicon; matrix solar cell technology with an efficiency of 25-30% upon the conversion of concentrated solar, thermal, and laser radiation; encapsulation technology for high-voltage silicon solar modules with a voltage up to 1000 V and a service life up to 50 years; new methods of concentration of solar radiation with the balancing illumination of photovoltaic cells at 50-100-fold concentration; and solar power systems with round-the-clock production of electrical energy that do not require energy storage devices and reserve sources of energy. The advanced tendency in silicon power engineering is the use of high-temperature reactions in heterogeneous modular silicate solutions for long-term (over one year) production of heat and electricity in the autonomous mode.

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  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. 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

  13. Electron beam induced grafting of N-isopropylacrylamide to a poly(ethylene-terephthalate) membrane for rapid cell sheet detachment

    International Nuclear Information System (INIS)

    Intact sheets of human prostate epithelium cells were successfully detached from a poly(N-isopropylacrylamide) (pNIPAM) membrane radiolytically grafted to poly(ethlylene-terephthalate (PET) culture dishes. The detachment process took less than 20 min without damaging the sheet structure. The grafting was performed using a high-energy electron beam to covalently bond NIPAM to the surface of PET culture dishes. This work demonstrates that the optimal conditions for uniform grafting can be achieved by adding argon-saturated solutions of NIPAM monomer onto pre-irradiated, surface-activated PET membranes. The solutions and the membranes were then irradiated under anaerobic conditions to a total absorbed dose of 25 kGy. This grafting method involves producing carbon-centered free radicals NIPAM· and PET· from both NIPAM and PET, respectively. An investigation of the kinetics of the early stages of polymerization of NIPAM was performed through electron beam pulse radiolysis with optical detection. The pulse radiolysis experiments of anaerobic NIPAM methanol solutions show that the esol·- reacts very rapidly with NIPAM producing NIPAM·- anions with a reaction rate constant of 1.4x109±10% L mol-1 s-1. The NIPAM·- anions then undergo a protonation reaction producing the initiation free radical (NIPAM·) with a reaction rate constant of 9x102 L mol-1 s-1. Along with pulse radiolysis, electron paramagnetic resonance (EPR) measurements show that the radiolytically produced carbon-centered free radicals of the PET, PET·, decay following an overall observed pseudo-first-order reaction with rate constants of k=2.0x10-4 and 7.0x10-4 s-1 produced in argon and in air, respectively. The overall observed decay reaction involve PET·+PET· cross-linking, PET·+O2, PET+HO2·, and PET+H-atoms, since these EPR measurements were conducted under aerobic conditions.

  14. Bladder Smooth Muscle Cells Differentiation from Dental Pulp Stem Cells: Future Potential for Bladder Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Bing Song

    2016-01-01

    Full Text Available Dental pulp stem cells (DPSCs are multipotent cells capable of differentiating into multiple cell lines, thus providing an alternative source of cell for tissue engineering. Smooth muscle cell (SMC regeneration is a crucial step in tissue engineering of the urinary bladder. It is known that DPSCs have the potential to differentiate into a smooth muscle phenotype in vitro with differentiation agents. However, most of these studies are focused on the vascular SMCs. The optimal approaches to induce human DPSCs to differentiate into bladder SMCs are still under investigation. We demonstrate in this study the ability of human DPSCs to differentiate into bladder SMCs in a growth environment containing bladder SMCs-conditioned medium with the addition of the transforming growth factor beta 1 (TGF-β1. After 14 days of exposure to this medium, the gene and protein expression of SMC-specific marker (α-SMA, desmin, and calponin increased over time. In particular, myosin was present in differentiated cells after 11 days of induction, which indicated that the cells differentiated into the mature SMCs. These data suggested that human DPSCs could be used as an alternative and less invasive source of stem cells for smooth muscle regeneration, a technology that has applications for bladder tissue engineering.

  15. Topographical atlas sheets

    Science.gov (United States)

    Wheeler, George Montague

    1876-01-01

    The following topographical atlas sheets, accompanying Appendix J.J. of the Annual Report of the Chief of Engineers, U.S. Army-being Annual Report upon U. S. Geographical Surveys-have been published during the fiscal year ending June 30, 1876, and are a portion of the series projected to embrace the territory of the United States lying west of the 100th meridian.

  16. 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.

  17. Synthesis and patterning of tunable multiscale materials with engineered cells

    Science.gov (United States)

    Chen, Allen Y.; Deng, Zhengtao; Billings, Amanda N.; Seker, Urartu O. S.; Lu, Michelle Y.; Citorik, Robert J.; Zakeri, Bijan; Lu, Timothy K.

    2014-05-01

    Many natural biological systems—such as biofilms, shells and skeletal tissues—are able to assemble multifunctional and environmentally responsive multiscale assemblies of living and non-living components. Here, by using inducible genetic circuits and cellular communication circuits to regulate Escherichia coli curli amyloid production, we show that E. coli cells can organize self-assembling amyloid fibrils across multiple length scales, producing amyloid-based materials that are either externally controllable or undergo autonomous patterning. We also interfaced curli fibrils with inorganic materials, such as gold nanoparticles (AuNPs) and quantum dots (QDs), and used these capabilities to create an environmentally responsive biofilm-based electrical switch, produce gold nanowires and nanorods, co-localize AuNPs with CdTe/CdS QDs to modulate QD fluorescence lifetimes, and nucleate the formation of fluorescent ZnS QDs. This work lays a foundation for synthesizing, patterning, and controlling functional composite materials with engineered cells.

  18. 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.

  19. 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. PMID:26592525

  20. 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.

  1. High Efficiency CdTe Ink-Based Solar Cells Using Nanocrystals (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    This NREL Highlight is being developed for the 2015 February Alliance S&T Board meeting and describes a solution-processable ink to produce high-efficiency solar cells using low temperature and simple processing.

  2. 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.

  3. Forces generated by cell intercalation tow epidermal sheets in mammalian tissue morphogenesis.

    Science.gov (United States)

    Heller, Evan; Kumar, K Vijay; Grill, Stephan W; Fuchs, Elaine

    2014-03-31

    While gastrulation movements offer mechanistic paradigms for how collective cellular movements shape developing embryos, far less is known about coordinated cellular movements that occur later in development. Studying eyelid closure, we explore a case where an epithelium locally reshapes, expands, and moves over another epithelium. Live imaging, gene targeting, and cell-cycle inhibitors reveal that closure does not require overlying periderm, proliferation, or supracellular actin cable assembly. Laser ablation and quantitative analyses of tissue deformations further distinguish the mechanism from wound repair and dorsal closure. Rather, cell intercalations parallel to the tissue front locally compress it perpendicularly, pulling the surrounding epidermis along the closure axis. Functional analyses in vivo show that the mechanism requires localized myosin-IIA- and α5β1 integrin/fibronectin-mediated migration and E-cadherin downregulation likely stimulated by Wnt signaling. These studies uncover a mode of epithelial closure in which forces generated by cell intercalation are leveraged to tow the surrounding tissue. PMID:24697897

  4. 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.

  5. How Do Cells Make Decisions: Engineering Micro- and Nanoenvironments for Cell Migration

    Directory of Open Access Journals (Sweden)

    Siti Hawa Ngalim

    2010-01-01

    Full Text Available Cell migration contributes to cancer metastasis and involves cell adhesion to the extracellular matrix (ECM, force generation through the cell's cytoskeletal, and finally cell detachment. Both adhesive cues from the ECM and soluble cues from neighbouring cells and tissue trigger intracellular signalling pathways that are essential for cell migration. While the machinery of many signalling pathways is relatively well understood, how hierarchies of different and conflicting signals are established is a new area of cellular cancer research. We examine the recent advances in microfabrication, microfluidics, and nanotechnology that can be utilized to engineer micro- and nanoscaled cellular environments. Controlling both adhesive and soluble cues for migration may allow us to decipher how cells become motile, choose the direction for migration, and how oncogenic transformations influences these decision-making processes.

  6. Van der Waals epitaxy of ultrathin α-MoO3 sheets on mica substrate with single-unit-cell thickness

    Science.gov (United States)

    Wang, Di; Li, Jing-Ning; Zhou, Yu; Xu, Di-Hu; Xiong, Xiang; Peng, Ru-Wen; Wang, Mu

    2016-02-01

    We report on van der Waals epitaxy of single-crystalline α-MoO3 sheets with single-unit-cell thickness on the mica substrate. The crystalline lattice structure, growth habits, and Raman spectra of the grown α-MoO3 sheets are analyzed. The anisotropic growth of α-MoO3 sheets can be understood by period bond chains theory. Unlike monolayer MoS2 or graphene, Raman spectra of α-MoO3 do not possess frequency shift from bulk crystal to single-unit-cell layer. The relative intensities of two Raman modes (Ag) at 159 and 818 cm-1 are sensitive to the polarization of incident light. This scenario provides a quick approach to determine the lattice orientation of α-MoO3 crystals. Our studies indicate that van der Waals epitaxial growth is a simple and effective way to fabricate high-quality ultrathin α-MoO3 sheets for physical property investigations and potential applications.

  7. Forces Generated by Cell Intercalation Tow Epidermal Sheets in Mammalian Tissue Morphogenesis

    OpenAIRE

    Heller, Evan; Kumar, K. Vijay; Grill, Stephan W.; Fuchs, Elaine

    2014-01-01

    While gastrulation movements offer mechanistic paradigms for how collective cellular movements shape developing embryos, far less is known about coordinated cellular movements that occur later in development. Studying eyelid closure, we explore a case where an epithelium locally reshapes, expands, and moves over another epithelium. Live imaging, gene targeting and cell cycle inhibitors reveal that closure does not require overlying periderm, proliferation or supracellular actin cable assembly...

  8. 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.

  9. 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.

  10. 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. PMID:26921521

  11. 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

  12. 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.

  13. 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

    2016-09-01

    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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  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. Steel Sheet Pile Walls in Soft Soil

    NARCIS (Netherlands)

    Kort, D.A.

    2002-01-01

    For almost a century, steel sheet pile walls are applied worldwide as earth retaining structures for excavations and quay walls. Within the framework of the development of European structural codes for Civil Engineering works, the Eurocodes, Eurocode 3 Part 5 for design of steel sheet pile walls was

  2. Stem Cells and Progenitor Cells for Tissue-Engineered Solutions to Congenital Heart Defects

    OpenAIRE

    Yang Gao; Jacot, Jeffrey G.

    2015-01-01

    Synthetic patches and fixed grafts currently used in the repair of congenital heart defects are nonliving, noncontractile, and not electrically responsive, leading to increased risk of complication, reoperation, and sudden cardiac death. Studies suggest that tissue-engineered patches made from living, functional cells could grow with the patient, facilitate healing, and help recover cardiac function. In this paper, we review the research into possible sources of cardiomyocytes and other cardi...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Electrospun nanofibrous sheets of collagen/elastin/polycaprolactone improve cardiac repair after myocardial infarction.

    Science.gov (United States)

    Liu, Yang; Xu, Yachen; Wang, Zhenhua; Wen, Dezhong; Zhang, Wentian; Schmull, Sebastian; Li, Haiyan; Chen, Yao; Xue, Song

    2016-01-01

    Electrospun nanofibrous sheets get increasing attention in myocardial infarction (MI) treatment due to their good cytocompatibility to deliver transplanted stem cells to infarcted areas and due to mechanical characteristics to support damaged tissue. Cardiac extracellular matrix is essential for implanted cells since it provides the cardiac microenvironment. In this study, we hypothesized high concentrations of cardiac nature protein (NP), namely elastin and collagen, in hybrid polycaprolactone (PCL) electrospun nanofibrous sheets could be effective as cardiac-mimicking patch. Optimal ratio of elastin and collagen with PCL in electrospun sheets (80% NP/PCL) was selected based on cytocompatibility and mechanical characteristics. Bone-marrow (BM) c-kit(+) cells anchoring onto NP/PCL sheets exhibited increased proliferative capacity compared with those seeded on PCL in vitro. Moreover, we examined the improvement of cardiac function in MI mice by cell-seeded cardiac patch. Green Fluorescent Protein (GFP)-labeled BM c-kit(+) cells were loaded on 80% NP/PCL sheets which was transplanted into MI mice. Both 80% NP/PCL and c-kit(+)-seeded 80% NP/PCL effectively improved cardiac function after 4 weeks of transplantation, with reduced infarction area and restricted LV remodeling. C-kit(+)-seeded 80% NP/PCL was even superior to the 80% NP/PCL alone and both superior to PCL. GFP(+) cells were identified both in the sheets and local infarcted area where transplanted cells underwent cardiac differentiation after 4 weeks. To the best of our knowledge, this is the first report that sheets with high concentrations of nature proteins loaded with BM c-kit(+) cells might be a novel promising candidate for tissue-engineered cardiac patch to improve cardiac repair after MI. PMID:27186292

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

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27250940

  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. Extraction and Assembly of Tissue-Derived Gels for Cell Culture and Tissue Engineering

    OpenAIRE

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L.; Weichselbaum, Ralph R.; Ervin, Natalia; Cankova, Zdravka; Eric M Brey

    2008-01-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately refle...

  12. Adipose-Derived Stem Cells for Tissue Engineering and Regenerative Medicine Applications

    OpenAIRE

    Ru Dai; Zongjie Wang; Roya Samanipour; Kyo-in Koo; Keekyoung Kim

    2016-01-01

    Adipose-derived stem cells (ASCs) are a mesenchymal stem cell source with properties of self-renewal and multipotential differentiation. Compared to bone marrow-derived stem cells (BMSCs), ASCs can be derived from more sources and are harvested more easily. Three-dimensional (3D) tissue engineering scaffolds are better able to mimic the in vivo cellular microenvironment, which benefits the localization, attachment, proliferation, and differentiation of ASCs. Therefore, tissue-engineered ASCs ...

  13. 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....

  14. 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...... spreading and osteogenic differentiation of human mesenchymal stem cells (hMSCs) into complex tissue-like structures. In summary, we have developed a tissue-like microgel array for evaluating stem cell differentiation within complex and heterogeneous cell microenvironments. We anticipate that the developed...

  15. Initial rigid response and softening transition of highly stretchable kirigami sheet materials

    Science.gov (United States)

    Isobe, Midori; Okumura, Ko

    2016-04-01

    We study, experimentally and theoretically, the mechanical response of sheet materials on which line cracks or cuts are arranged in a simple pattern. Such sheet materials, often called kirigami (the Japanese words, kiri and gami, stand for cut and paper, respectively), demonstrate a unique mechanical response promising for various engineering applications such as stretchable batteries: kirigami sheets possess a mechanical regime in which sheets are highly stretchable and very soft compared with the original sheets without line cracks, by virtue of out-of-plane deformation. However, this regime starts after a transition from an initial stiff regime governed by in-plane deformation. In other words, the softness of the kirigami structure emerges as a result of a transition from the two-dimensional to three-dimensional deformation, i.e., from stretching to bending. We clarify the physical origins of the transition and mechanical regimes, which are revealed to be governed by simple scaling laws. The results could be useful for controlling and designing the mechanical response of sheet materials including cell sheets for medical regeneration and relevant to the development of materials with tunable stiffness and mechanical force sensors.

  16. Current progress of skin tissue engineering: Seed cells, bioscaffolds, and construction strategies

    Directory of Open Access Journals (Sweden)

    Huanjing Bi

    2013-09-01

    Full Text Available The development of cell biology, molecular biology, and material science, has been propelling biomimic tissue-engineered skins to become more sophisticated in scientificity and more simplified in practicality. In order to improve the safety, durability, elasticity, biocompatibility, and clinical efficacy of tissue-engineered skin, several powerful seed cells have already found their application in wound repair, and a variety of bioactive scaffolds have been discovered to influence cell fate in epidermogenesis. These exuberant interests provide insights into advanced construction strategies for complex skin mimics. Based on these exciting developments, a complete full-thickness tissue-engineered skin is likely to be generated.

  17. Mature adipocytes may be a source of stem cells for tissue engineering

    International Nuclear Information System (INIS)

    Adipose tissue contains a large portion of stem cells. These cells appear morphologically like fibroblasts and are primarily derived from the stromal cell fraction. Mature (lipid-filled) adipocytes possess the ability to become proliferative cells and have been shown to produce progeny cells that possess the same morphological (fibroblast-like) appearance as the stem cells from the stromal fraction. A closer examination of mature adipocyte-derived progeny cells may prove to be an emerging area of growth/metabolic physiology that may modify present thinking about adipose tissue renewal capabilities. Knowledge of these cells may also prove beneficial in cell-based therapies for tissue repair, regeneration, or engineering

  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. 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.

  20. PVC Plastic and Vinyl Sheet Flooring in the Practice of Construction Engineering%PVC塑胶卷材地面在工程中的应用

    Institute of Scientific and Technical Information of China (English)

    黄昳

    2011-01-01

    本文针对PVC塑胶卷材地面在施工中存在的难度,提出一系列措施,提高了施工质量,达到了工程施工的预期效果。%This article points to the problem in the construction of PVC sheet flooring,puts forward serial measures,enhances the construction quality,and achieves the desired results.

  1. 1984: On monitoring cell fate in three-dimensional polymeric scaffolds for tissue engineering applications

    OpenAIRE

    Leferink, Anne Marijke

    2014-01-01

    In cartilage and bone engineering there is a high need for methods to replace traditional tissue and organ transplantation approaches to overcome the currently faced problems of donor shortage and invasiveness of the transplantation procedure. Although many promising advances have been made in the past decades in in vitro tissue engineering, quality control remains a challenge. Most conventional methods to assess the quality of a tissue engineered construct, e.g. by studying cell fate and tis...

  2. 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....

  3. Cells by design: a mini-review of targeting cell engineering using DNA microarrays.

    Science.gov (United States)

    Jaluria, Pratik; Chu, Chia; Betenbaugh, Michael; Shiloach, Joseph

    2008-06-01

    Recent studies have demonstrated the utility of DNA microarray technology in engineering cellular properties. For instance, cellular adhesion, the necessity of cells to attach to a surface in order to to proliferate, was examined by comparing two distinct HeLa cell lines. Two genes, one encoding a type II membrane glycosylating sialyltransferase (siat7e) and the other encoding a secreted glycoprotein (lama4), were found to influence adhesion. The expression of siat7e correlated with reduced adhesion, whereas expression of lama4 correlated with increased adhesion, as shown by various assays. In a separate example, a gene encoding a mitochondrial assembly protein (cox15) and a gene encoding a kinase (cdkl3), were found to influence cellular growth. Enhanced expression of either gene resulted in slightly higher specific growth rates and higher maximum cell densities for HeLa, HEK-293, and CHO cell lines. Another investigated property was the adaptation of HEK-293 cells to serum-free media. The genes egr1 and gas6, both with anti-apoptotic properties, were identified as potentially improving adaptability by impacting viability at low serum levels. In trying to control apoptosis, researchers found that by altering the expression levels of four genes faim, fadd, alg-2, and requiem, apoptotic response could be altered. In the present work, these and related studies in microorganisms (prokaryote and eukaryote) are examined in greater detail focusing on the approach of using DNA microarrays to direct cellular behavior by targeting select genes. PMID:18327555

  4. Prospects of microbial cell factories developed through systems metabolic engineering.

    Science.gov (United States)

    Gustavsson, Martin; Lee, Sang Yup

    2016-09-01

    While academic-level studies on metabolic engineering of microorganisms for production of chemicals and fuels are ever growing, a significantly lower number of such production processes have reached commercial-scale. In this work, we review the challenges associated with moving from laboratory-scale demonstration of microbial chemical or fuel production to actual commercialization, focusing on key requirements on the production organism that need to be considered during the metabolic engineering process. Metabolic engineering strategies should take into account techno-economic factors such as the choice of feedstock, the product yield, productivity and titre, and the cost effectiveness of midstream and downstream processes. Also, it is important to develop an industrial strain through metabolic engineering for pathway construction and flux optimization together with increasing tolerance to products and inhibitors present in the feedstock, and ensuring genetic stability and strain robustness under actual fermentation conditions. PMID:27435545

  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. Apparatus for measuring the finite load-deformation behavior of a sheet of epithelial cells cultured on a mesoscopic freestanding elastomer membrane

    International Nuclear Information System (INIS)

    Details are given for the design, calibration, and operation of an apparatus for measuring the finite load-deformation behavior of a sheet of living epithelial cells cultured on a mesoscopic freestanding elastomer membrane, 10 μm thick and 5 mm in diameter. Although similar in concept to bulge tests used to investigate the mechanical properties of micromachined thin films, cell-elastomer composite diaphragm inflation tests pose a unique set of experimental challenges. Composite diaphragm (CD) specimens are extremely compliant (EMIN=0 μl, VMAX≤40 μl) while simultaneously recording the inflation pressure acting at the fixed boundary of the specimen, p(r=a). Using a carefully prescribed six-cycle inflation test protocol, the apparatus is shown to be capable of measuring the [V,p(r=a)] inflation response of a cell-elastomer CD with random uncertainties estimated at ±0.45 μl and ±2.5 Pa, respectively

  8. 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.

  9. 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.

  10. 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. PMID:16989722

  11. 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.

  12. 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.

  13. 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.

  14. Induction of insulin secretion in engineered liver cells by nitric oxide

    Directory of Open Access Journals (Sweden)

    Özcan Sabire

    2007-10-01

    Full Text Available Abstract Background Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs in a glucose-independent manner. In the present study we engineered liver cells to produce and secrete insulin and insulin secretion can be stimulated via the nitric oxide pathway. Results Expression of either human insulin or the beta cell specific transcription factors PDX-1, NeuroD1 and MafA in the Hepa1-6 cell line or primary liver cells via adenoviral gene transfer, results in production and secretion of insulin. Although, the secretion of insulin is not significantly increased in response to high glucose, treatment of these engineered liver cells with L-arginine stimulates insulin secretion up to three-fold. This L-arginine-mediated insulin release is dependent on the production of nitric oxide. Conclusion Liver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.

  15. 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.

  16. GASN sheets

    International Nuclear Information System (INIS)

    This document gathers around 50 detailed sheets which describe and present various aspects, data and information related to the nuclear sector or, more generally to energy. The following items are addressed: natural and artificial radioactive environment, evolution of energy needs in the world, radioactive wastes, which energy for France tomorrow, the consequences in France of the Chernobyl accident, ammunitions containing depleted uranium, processing and recycling of used nuclear fuel, transport of radioactive materials, seismic risk for the basic nuclear installations, radon, the precautionary principle, the issue of low doses, the EPR, the greenhouse effect, the Oklo nuclear reactors, ITER on the way towards fusion reactors, simulation and nuclear deterrence, crisis management in the nuclear field, does nuclear research put a break on the development of renewable energies by monopolizing funding, nuclear safety and security, the plutonium, generation IV reactors, comparison of different modes of electricity production, medical exposure to ionizing radiations, the control of nuclear activities, food preservation by ionization, photovoltaic solar collectors, the Polonium 210, the dismantling of nuclear installations, wind energy, desalination and nuclear reactors, from non-communication to transparency about nuclear safety, the Jules Horowitz reactor, CO2 capture and storage, hydrogen, solar energy, the radium, the subcontractors of maintenance of the nuclear fleet, biomass, internal radio-contamination, epidemiological studies, submarine nuclear propulsion, sea energy, the Three Mile Island accident, the Chernobyl accident, the Fukushima accident, the nuclear after Fukushima

  17. 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. PMID:25900048

  18. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    OpenAIRE

    Alexander Röder; Elena García-Gareta; Christina Theodoropoulos; Nikola Ristovski; Keith A. Blackwood; Woodruff, Maria A.

    2015-01-01

    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 ...

  19. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    OpenAIRE

    Wei Luo; Abigail Pulsipher; Debjit Dutta; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-01-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture ...

  20. 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.

  1. 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

  2. Characterisation of BHK-21 cells engineered to secrete human insulin

    OpenAIRE

    Gammell, Patrick; O'Driscoll, Lorraine; Clynes, Martin

    2003-01-01

    Autoimmune destruction of β cells in the pancreas leads to type I, or insulin dependent diabetes mellitus (IDDM), through the loss of endogenous insulin production capacity. This paper describes an attempt to generate ‘artificial’β cells using the fibroblast cell line BHK21. Stable transfectants expressing the human preproinsulin (PPI) gene were isolated and characterised. The resulting clone selected for further analysis (BHK-PPI-C16) was capable of secreting 0.12 pmol proinsulin/hr/105 cell...

  3. Engineering of the Embryonic and Adult Stem Cell Niches

    OpenAIRE

    Hosseinkhani, Mohsen; Shirazi, Reza; Rajaei, Farzad; Mahmoudi, Masoud; Mohammadi, Navid; Abbasi, Mahnaz

    2013-01-01

    Context Stem cells have the potential to generate a renewable source of cells for regenerative medicine due to their ability to self-renew and differentiate to various functional cell types of the adult organism. The extracellular microenvironment plays a pivotal role in controlling stem cell fate responses. Therefore, identification of appropriate environmental stimuli that supports cellular proliferation and lineage-specific differentiation is critical for the clinical application of the st...

  4. 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

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

    NARCIS (Netherlands)

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

    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

  6. 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.

  7. 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.

  8. Engineering cell-fluorescent ion track hybrid detectors

    International Nuclear Information System (INIS)

    The lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response. Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystals combined with confocal laser scanning microscopy (CLSM) provide 3D information on ion tracks with a resolution limited by light diffraction. Here we report the development of next generation cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). The biocompatibility of FNTDs was tested using six different cell lines, i.e. human non-small cell lung carcinoma (A549), glioblastoma (U87), androgen independent prostate cancer (PC3), epidermoid cancer (A431) and murine (VmDk) glioma SMA-560. To evaluate cell adherence, viability and conformal coverage of the crystals different seeding densities and alternative coating with extracellular matrix (fibronectin) was tested. Carbon irradiation was performed in Bragg peak (initial 270.55 MeV u−1). A series of cell compartment specific fluorescence stains including nuclear (HOECHST), membrane (Glut-1), cytoplasm (Calcein AM, CM-DiI) were tested on Cell-Fit-HDs and a single CLSM was employed to co-detect the physical (crystal) as well as the biological (cell layer) information. The FNTD provides a biocompatible surface. Among the cells tested, A549 cells formed the most uniform, viable, tightly packed epithelial like monolayer. The ion track information was not compromised in Cell-Fit-HD as compared to the FNTD alone. Neither cell coating and culturing, nor additional staining procedures affected the properties of the FNTD surface to detect ion tracks. Standard immunofluorescence and live staining procedures could be employed to co-register cell biology and ion track information. The Cell-Fit-Hybrid Detector system is a promising platform for a multitude of studies linking biological response to energy deposition at high level of optical microscopy resolution

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

    Science.gov (United States)

    Guermani, Enrico; Shaki, Hossein; Mohanty, Soumyaranjan; Mehrali, Mehdi; Arpanaei, Ayyoob; Gaharwar, Akhilesh K.; Dolatshahi-Pirouz, Alireza

    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-laden microgel arrays. The developed microgel array platform consisted of various microgel environments that where composed of native-like cellular microarchitectures resembling vascularized and bone marrow tissue architectures. The feasibility of our array system was demonstrated through localized cell spreading and osteogenic differentiation of human mesenchymal stem cells (hMSCs) into complex tissue-like structures. In summary, we have developed a tissue-like microgel array for evaluating stem cell differentiation within complex and heterogeneous cell microenvironments. We anticipate that the developed platform will be used for high-throughput identification of combinatorial and native-like scaffolds for tissue engineering of functional organs. PMID:27465860

  10. 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.

  11. 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

  12. 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...

  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. 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.

  15. In vitro evaluation of cell-seeded chitosan films for peripheral nerve tissue engineering

    OpenAIRE

    Wrobel, Sandra; Serra, Sofia Cristina; Samy, S. M.; Sousa, Nuno; Heimann, Claudia; Barwig, Christina; Grothe, Claudia; Salgado, A. J.; Talini, Kirsten Haastert

    2014-01-01

    Natural biomaterials have attracted an increasing interest in the field of tissue-engineered nerve grafts, representing a possible alternative to autologous nerve transplantation. With the prospect of developing a novel entubulation strategy for transected nerves with cell-seeded chitosan films, we examined the biocompatibility of such films in vitro. Different types of rat Schwann cells (SCs)—immortalized, neonatal, and adult—as well as rat bone-marrow-derived mesenchymal stromal cells (BMSC...

  16. CRISPR/Cas9-mediated genome engineering of CHO cell factories: application and perspectives

    DEFF Research Database (Denmark)

    Lee, Jae Seong; Grav, Lise Marie; Lewis, Nathan E.;

    2015-01-01

    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 takenon a new aspect through targeted genome editing. The bacterial clustered regularly interspacedshort palindromic...... highlighting both future perspectivesand challenges. As one of the main drivers for the CHO systems biology era, genome engineeringwith CRISPR/Cas9 will pave the way for rational design of CHO cell factories....

  17. Engineering Adolescence: Maturation of Human Pluripotent Stem Cell-derived Cardiomyocytes

    OpenAIRE

    Yang, Xiulan; Pabon, Lil; Murry, Charles E.

    2014-01-01

    The discovery of human pluripotent stem cells (hPSCs), including both human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), has opened up novel paths for a wide range of scientific studies. The capability to direct the differentiation of hPSCs into functional cardiomyocytes has provided a platform for regenerative medicine, development, tissue engineering, disease modeling, and drug toxicity testing. Despite exciting progress, achieving the optimal benefits has...

  18. 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

  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. 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 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...

  1. 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...

  2. 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...

  3. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    Science.gov (United States)

    Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-09-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies.

  4. 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)

  5. Design of high temperature irradiation materials inspection cells. (Spent fuel inspection cells) in the High Temperature Engineering Test Reactor

    International Nuclear Information System (INIS)

    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)

  6. Engineered nanoparticles mimicking cell membranes for toxin neutralization.

    Science.gov (United States)

    Fang, Ronnie H; Luk, Brian T; Hu, Che-Ming J; Zhang, Liangfang

    2015-08-01

    Protein toxins secreted from pathogenic bacteria and venomous animals rely on multiple mechanisms to overcome the cell membrane barrier to inflict their virulence effect. A promising therapeutic concept toward developing a broadly applicable anti-toxin platform is to administer cell membrane mimics as decoys to sequester these virulence factors. As such, lipid membrane-based nanoparticulates are an ideal candidate given their structural similarity to cellular membranes. This article reviews the virulence mechanisms employed by toxins at the cell membrane interface and highlights the application of cell-membrane mimicking nanoparticles as toxin decoys for systemic detoxification. In addition, the implication of particle/toxin nanocomplexes in the development of toxoid vaccines is discussed. PMID:25868452

  7. 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.

  8. 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. PMID:26070720

  9. 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.

  10. Hematopoietic Stem Cell Targeting with Surface-Engineered Lentiviral Vectors

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Els Verhoeyen and Francois-Loic Cosset Adapted from [*Gene Transfer: Delivery and Expression of DNA and RNA*](http://www.cshlpress.com/link/genetrnp.htm) (eds. Friedmann and Rossi). CSHL Press, Cold Spring Harbor, NY, USA, 2007. ### INTRODUCTION In the protocol presented here, hematopoietic stem cells (HSCs) are specifically transduced with a vector displaying the HSC-activating polypeptides, stem cell factor (SCF) and thrombopoietin (TPO). Targeted HSC transduction is e...

  11. 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.

  12. Process Engineering of Stem Cells for Clinical Application

    OpenAIRE

    Serra, Maria Margarida de Carvalho Negrão

    2011-01-01

    Over the last decade, human embryonic stem cells (hESCs) have garnered a lot of attention owing to their inherent self-renewal ability and pluripotency. These characteristics have opened opportunities for potential stem cell-based regenerative medicines, for development of drug discovery platforms and as unique in vitro models for the study of early human development.(...) Fundação para a Ciência e a Tecnologia

  13. 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; Hilkens, Petra

    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

  14. Microfluidic Buffer Exchange for Interference-free Micro/Nanoparticle Cell Engineering.

    Science.gov (United States)

    Tay, Hui Min; Yeo, David C; Wiraja, Christian; Xu, Chenjie; Hou, Han Wei

    2016-01-01

    Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic properties, enable bio imaging and control cell phenotype. A critical yet inadequately addressed issue is the significant number of particles that remain unbound after cell labeling which cannot be readily removed by conventional centrifugation. This leads to an increase in bio imaging background noise and can impart transformative effects onto neighboring non-target cells. In this protocol, we present an inertial microfluidics-based buffer exchange strategy termed as Dean Flow Fractionation (DFF) to efficiently separate labeled cells from free NPs in a high throughput manner. The developed spiral microdevice facilitates continuous collection (>90% cell recovery) of purified cells (THP-1 and MSCs) suspended in new buffer solution, while achieving >95% depletion of unbound fluorescent dye or dye-loaded NPs (silica or PLGA). This single-step, size-based cell purification strategy enables high cell processing throughput (10(6) cells/min) and is highly useful for large-volume cell purification of micro/nanoparticle engineered cells to achieve interference-free clinical application. PMID:27500904

  15. 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

  16. Bioreactor systems for tissue engineering II. Strategies for the expansion and directed differentiation of stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, Cornelia [Hannover Univ. (Germany). Inst. fuer Technische Chemie; Griensven, Martijn van [Ludwig Boltzmann Institut fuer Klinische und Experimentelle Traumatologie, Wien (Austria); Poertner, Ralf (eds.) [Technische Univ. Hamburg-Harburg (Germany). Inst. Biotechnologie und Verfahrenstechnik

    2010-07-01

    Alternative Sources of Adult Stem Cells: Human Amniotic Membrane, by S. Wolbank, M. van Griensven, R. Grillari-Voglauer, and A. Peterbauer-Scherb; - Mesenchymal Stromal Cells Derived from Human Umbilical Cord Tissues: Primitive Cells with Potential for Clinical and Tissue Engineering Applications, by P. Moretti, T. Hatlapatka, D. Marten, A. Lavrentieva, I. Majore, R. Hass and C. Kasper; - Isolation, Characterization, Differentiation, and Application of Adipose-Derived Stem Cells, by J. W. Kuhbier, B. Weyand, C. Radtke, P. M. Vogt, C. Kasper and K. Reimers; - Induced Pluripotent Stem Cells: Characteristics and Perspectives, by T. Cantz and U. Martin; - Induced Pluripotent Stem Cell Technology in Regenerative Medicine and Biology, by D. Pei, J. Xu, Q. Zhuang, H.-F. Tse and M. A. Esteban; - Production Process for Stem Cell Based Therapeutic Implants: Expansion of the Production Cell Line and Cultivation of Encapsulated Cells, by C. Weber, S. Pohl, R. Poertner, P. Pino-Grace, D. Freimark, C. Wallrapp, P. Geigle and P. Czermak; - Cartilage Engineering from Mesenchymal Stem Cells, by C. Goepfert, A. Slobodianski, A.F. Schilling, P. Adamietz and R. Poertner; - Outgrowth Endothelial Cells: Sources, Characteristics and Potential Applications in Tissue Engineering and Regenerative Medicine, by S. Fuchs, E. Dohle, M. Kolbe, C. J. Kirkpatrick; - Basic Science and Clinical Application of Stem Cells in Veterinary Medicine, by I. Ribitsch, J. Burk, U. Delling, C. Geissler, C. Gittel, H. Juelke, W. Brehm; - Bone Marrow Stem Cells in Clinical Application: Harnessing Paracrine Roles and Niche Mechanisms, by R. M. El Backly, R. Cancedda; - Clinical Application of Stem Cells in the Cardiovascular System, C. Stamm, K. Klose, Y.-H. Choi. (orig.)

  17. 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

  18. 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.

  19. 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....

  20. 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.

  1. 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...... cells with increased content of ARA and EPA. The invention especially involves improvement of the PUFA content in the host organism through various over-expression of e.g. cytochrome b5 and cytochrome b5 reductase involved in fatty acid desaturation, and heterologous expression of cytochrome b5...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. A Dual Receptor and Reporter for Multi-Modal Cell Surface Engineering.

    Science.gov (United States)

    Luo, Wei; Westcott, Nathan; Dutta, Debjit; Pulsipher, Abigail; Rogozhnikov, Dmitry; Chen, Jean; Yousaf, Muhammad N

    2015-10-16

    The rapid development of new small molecule drugs, nanomaterials, and genetic tools to modulate cellular function through cell surface manipulation has revolutionized the diagnosis, study, and treatment of disorders in human health. Since the cell membrane is a selective gateway barrier that serves as the first line of defense/offense and communication to its environment, new approaches that molecularly engineer or tailor cell membrane surfaces would allow for a new era in therapeutic design, therapeutic delivery, complex coculture tissue construction, and in situ imaging probe tracking technologies. In order to develop the next generation of multimodal therapies, cell behavior studies, and biotechnologies that focus on cell membrane biology, new tools that intersect the fields of chemistry, biology, and engineering are required. Herein, we develop a liposome fusion and delivery strategy to present a novel dual receptor and reporter system at cell surfaces without the use of molecular biology or metabolic biosynthesis. The cell surface receptor is based on bio-orthogonal functional groups that can conjugate a range of ligands while simultaneously reporting the conjugation through the emission of fluorescence. We demonstrate this dual receptor and reporter system by conjugating and tracking various cell surface ligands for temporal control of cell fluorescent signaling, cell-cell interaction, and tissue assembly construction. PMID:26204094

  8. 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.

  9. 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 ...

  10. Construction of tissue-engineered heart valves by using decellularized scaffolds and endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    FANG Ning-tao; XIE Shang-zhe; WANG Song-mei; GAO Hong-yang; WU Chun-gen; PAN Luan-feng

    2007-01-01

    Background Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells (EPCs) and decellularized valve scaffolds.Methods Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 × 106 cells/cm2 and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction (RT-PCR) analysis for the expression of endothelial nitric oxide synthase (eNOS) and tissue-type plasminogen activator (t-PA).Results EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor (vWF) and CD31, bound a human endothelial cell-specific lectin,Ulex Europaeus agglutinin-1 (UEA-1), and took up Dil-labeled low density lipoprotein (Dil-Ac-LDL). After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the

  11. 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.

  12. 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.

  13. 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

  14. A systems-level approach for metabolic engineering of yeast cell factories.

    Science.gov (United States)

    Kim, Il-Kwon; Roldão, António; Siewers, Verena; Nielsen, Jens

    2012-03-01

    The generation of novel yeast cell factories for production of high-value industrial biotechnological products relies on three metabolic engineering principles: design, construction, and analysis. In the last two decades, strong efforts have been put on developing faster and more efficient strategies and/or technologies for each one of these principles. For design and construction, three major strategies are described in this review: (1) rational metabolic engineering; (2) inverse metabolic engineering; and (3) evolutionary strategies. Independent of the selected strategy, the process of designing yeast strains involves five decision points: (1) choice of product, (2) choice of chassis, (3) identification of target genes, (4) regulating the expression level of target genes, and (5) network balancing of the target genes. At the construction level, several molecular biology tools have been developed through the concept of synthetic biology and applied for the generation of novel, engineered yeast strains. For comprehensive and quantitative analysis of constructed strains, systems biology tools are commonly used and using a multi-omics approach. Key information about the biological system can be revealed, for example, identification of genetic regulatory mechanisms and competitive pathways, thereby assisting the in silico design of metabolic engineering strategies for improving strain performance. Examples on how systems and synthetic biology brought yeast metabolic engineering closer to industrial biotechnology are described in this review, and these examples should demonstrate the potential of a systems-level approach for fast and efficient generation of yeast cell factories. PMID:22188344

  15. 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. PMID:27226765

  16. Reverse engineering validation using a benchmark synthetic gene circuit in human cells.

    Science.gov (United States)

    Kang, Taek; White, Jacob T; Xie, Zhen; Benenson, Yaakov; Sontag, Eduardo; Bleris, Leonidas

    2013-05-17

    Multicomponent biological networks are often understood incompletely, in large part due to the lack of reliable and robust methodologies for network reverse engineering and characterization. As a consequence, developing automated and rigorously validated methodologies for unraveling the complexity of biomolecular networks in human cells remains a central challenge to life scientists and engineers. Today, when it comes to experimental and analytical requirements, there exists a great deal of diversity in reverse engineering methods, which renders the independent validation and comparison of their predictive capabilities difficult. In this work we introduce an experimental platform customized for the development and verification of reverse engineering and pathway characterization algorithms in mammalian cells. Specifically, we stably integrate a synthetic gene network in human kidney cells and use it as a benchmark for validating reverse engineering methodologies. The network, which is orthogonal to endogenous cellular signaling, contains a small set of regulatory interactions that can be used to quantify the reconstruction performance. By performing successive perturbations to each modular component of the network and comparing protein and RNA measurements, we study the conditions under which we can reliably reconstruct the causal relationships of the integrated synthetic network.

  17. 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

  18. 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.

  19. Apparatus for measuring the finite load-deformation behavior of a sheet of epithelial cells cultured on a mesoscopic freestanding elastomer membrane

    Science.gov (United States)

    Selby, John C.; Shannon, Mark A.

    2007-09-01

    Details are given for the design, calibration, and operation of an apparatus for measuring the finite load-deformation behavior of a sheet of living epithelial cells cultured on a mesoscopic freestanding elastomer membrane, 10μm thick and 5mm in diameter. Although similar in concept to bulge tests used to investigate the mechanical properties of micromachined thin films, cell-elastomer composite diaphragm inflation tests pose a unique set of experimental challenges. Composite diaphragm (CD) specimens are extremely compliant (Epump integrated with a modular specimen mounting fixture that constitutes a horizontally semi-infinite reservoir of liquid culture medium. In a deformation-controlled inflation test, pressurized air is used to inflate a CD specimen into the liquid reservoir with minimum disturbance of the liquid-air interface. Piston displacements and absolute pump chamber air pressures are utilized as feedback to cycle the displaced (or inflated) CD volume V in a 0.05Hz triangular or sinusoidal wave form (VMIN=0μl, VMAX⩽40μl) while simultaneously recording the inflation pressure acting at the fixed boundary of the specimen, p(r =a). Using a carefully prescribed six-cycle inflation test protocol, the apparatus is shown to be capable of measuring the [V,p(r=a)] inflation response of a cell-elastomer CD with random uncertainties estimated at ±0.45μl and ±2.5Pa, respectively.

  20. 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.

  1. Can Engineered “Designer” T Cells Outsmart Chronic Hepatitis B?

    Science.gov (United States)

    Protzer, U.; Abken, H.

    2010-01-01

    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. PMID:21188203

  2. 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.

  3. 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

    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....... 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...

  4. 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

  5. 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.

  6. Interface engineering for efficient fullerene-free organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shivanna, Ravichandran; Narayan, K. S., E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); Rajaram, Sridhar, E-mail: rajaram@jncasr.ac.in, E-mail: narayan@jncasr.ac.in [International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  7. Allogeneic Transplantation of Periodontal Ligament-Derived Multipotent Mesenchymal Stromal Cell Sheets in Canine Critical-Size Supra-Alveolar Periodontal Defect Model

    OpenAIRE

    Tsumanuma, Yuka; Iwata, Takanori; Kinoshita, Atsuhiro; Washio, Kaoru; Yoshida, Toshiyuki; Yamada, Azusa; Takagi, Ryo; Yamato, Masayuki; Okano, Teruo; Izumi, Yuichi

    2016-01-01

    Abstract Periodontitis is a chronic inflammatory disease that induces the destruction of tooth-supporting tissues, followed by tooth loss. Although several approaches have been applied to periodontal regeneration, complete periodontal regeneration has not been accomplished. Tissue engineering using a combination of cells and scaffolds is considered to be a viable alternative strategy. We have shown that autologous transplantation of periodontal ligament-derived multipotent mesenchymal stromal...

  8. 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.

  9. 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.

  10. Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

    OpenAIRE

    Hipp, Jason; Atala, Anthony

    2004-01-01

    Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell...

  11. Stem Cell Hydrogel, Jump-Starting Zika Drug Discovery, and Engineering RNA Recognition.

    Science.gov (United States)

    Kostic, Milka

    2016-08-18

    Every month the editors of Cell Chemical Biology bring you highlights of the most recent chemical biology literature that impressed them with creativity and potential for follow up work. Our August 2016 selection includes a description of hydrogels with self-tunable stiffness that are used to profile lipid metabolites during stems cell differentiation, a look at whether we can find a drug repurposing solution to Zika virus infection, and an engineered RNA recognition motif (RRM). PMID:27541191

  12. Toward a bioengineered heparin: Challenges and strategies for metabolic engineering of mammalian cells

    OpenAIRE

    Baik, Jong Youn; Wang, Clifford L.; Bo YANG; Linhardt, Robert J.; Sharfstein, Susan T.

    2012-01-01

    Heparin is the most widely used pharmaceutical to control blood coagulation in modern medicine. A health crisis that took place in 2008 led to a demand for production of heparin from non-animal sources. Since Chinese hamster ovary (CHO) cells are capable of producing heparan sulfate (HS), a related polysaccharide naturally, and heparin and HS share the same biosynthetic pathway, we hypothesized that heparin could be produced in CHO cells by metabolic engineering. We developed stable human N-d...

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

    OpenAIRE

    Uma Maheswari Krishnan; Swaminathan Sethuraman

    2013-01-01

    Introduction: Successful tissue engineering strategies leading to the regeneration of a tissue depend on many factors, starting from the choice of appropriate scaffold material, tailoring the surface functionalities and topography, providing the correct amount of chemical and mechanical stimuli at the appropriate time points, and ensuring the uniform and precise localization of cells. Further challenges arise when more than one cell type has to be employed for the effective regeneration of an...

  14. Cardiovascular tissue engineering and regeneration based on adipose tissue-derived stem/stromal cells

    OpenAIRE

    Parvizi, Mojtaba

    2016-01-01

    Currently, the pre-clinical field is rapidly progressing in search of new therapeutic modalities that replace or complement current medication to treat cardiovascular disease. Among these are the single or combined use of stem cells, biomaterials and instructive factors, which together form the triad of tissue engineering and regenerative medicine. Stem cell therapy is a promising approach for repair, remodeling and even regenerate tissue of otherwise irreparable damage, such as after myocard...

  15. 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.

  16. GENETIC ENGINEERING NEURAL STEM CELL MODIFIED BY LENTIVIRUS FOR REPAIR OF SPINAL CORD INJURY IN RATS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To explore the feasibility for therapy of spinal cord injury (SCI) by genetic engineering neural stem cell (NSC) modified by lentiviral vector.Methods Following the construction of the genetic engineering NSC modified by lentivirus to secrete both neurotrophic factor-3 ( NT-3 ) and green fluorescence protein (GFP), hemisection of spinal cord at the level of T10 was performed in 56 adult Wistar rats that were randomly divided into 4 groups (n=14), namely 3 therapeutic groups and 1 control group. The therapeutic groups were dealed with NSC, genetic engineering NSC, and concentrated lentiviral supernatant which carries both GFP and NT-3, respectively. Then used fluorescence microscope to detect the transgenic expression in vitro and in vivo, migration of the grafted cells in vivo, and used the Basso, Beattie, and Bresnahan (BBB) open-field locomotor test to assess the recovery of function.Results The transplanted cells could survive for long time in vivo and migrate for long distance. The stable transgenic expression could be detected in vivo. The hindlimb function of the injured rats in 3 therapeutic groups, especially those dealed with genetic engineering NSC, improved obviously.Conclusion It is feasible to combine NSC with lentivirus for the repair of SCL NSC modified by lentivirus to deliver NT-3, acting as a source of neurotrophic factors and function cell in vivo, has the potential to participate in spinal cord repair.

  17. 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

  18. 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

  19. 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…

  20. 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...

  1. Chimeric Antigen Receptor-Engineered T Cells for Immunotherapy of Cancer

    Directory of Open Access Journals (Sweden)

    Marc Cartellieri

    2010-01-01

    Full Text Available CD4+ and CD8+ T lymphocytes are powerful components of adaptive immunity, which essentially contribute to the elimination of tumors. Due to their cytotoxic capacity, T cells emerged as attractive candidates for specific immunotherapy of cancer. A promising approach is the genetic modification of T cells with chimeric antigen receptors (CARs. First generation CARs consist of a binding moiety specifically recognizing a tumor cell surface antigen and a lymphocyte activating signaling chain. The CAR-mediated recognition induces cytokine production and tumor-directed cytotoxicity of T cells. Second and third generation CARs include signal sequences from various costimulatory molecules resulting in enhanced T-cell persistence and sustained antitumor reaction. Clinical trials revealed that the adoptive transfer of T cells engineered with first generation CARs represents a feasible concept for the induction of clinical responses in some tumor patients. However, further improvement is required, which may be achieved by second or third generation CAR-engrafted T cells.

  2. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering

    Science.gov (United States)

    Rosa, Vinicius; Dubey, Nileshkumar; Islam, Intekhab; Min, Kyung-San; Nör, Jacques E.

    2016-01-01

    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. PMID:27313627

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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...... protein production has increased significantly because proteomics can track changes in protein levels for different cell lines over time, which can be advantageous for bioprocess development and optimization. Specifically, the identification of proteins that affect cell culture processes can aid efforts...... 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...

  8. Could Life Originate between Mica Sheets?

    Science.gov (United States)

    Hansma, Helen

    2014-11-01

    Muscovite mica has many advantages as a site for the origins of life. Some of these advantages are: A. Spaces between mica sheets serve as cell-like compartments. B. K+ ions bridge Muscovite mica sheets, providing a high K+ environment, as found in all living cells. C. Mica's hexagonal 0.5-nm clay crystal lattice is comparable to the length of the amino acids, sugars, and nucleotides that polymerize to form life's major biological macromolecules. D. Mechanical energy from mica sheets, moving in response to water flows and temperature changes, provide an endless energy source for forming chemical bonds, rearranging polymers, and blebbing off protocells in a primitive form of cell division. How might fluid dynamics in the planar nanometer- to micron-high spaces between mica sheets affect the processes involved in the origins of life?

  9. 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.

  10. The Response of Human Mesenchymal Stem Cells to Osteogenic Signals and its Impact on Bone Tissue Engineering

    NARCIS (Netherlands)

    Siddappa, Ramakrishnaiah; Fernandes, Hugo; Liu, Jun; Blitterswijk, van Clemens; Boer, de Jan

    2007-01-01

    Bone tissue engineering using human mesenchymal stem cells (hMSCs) is a multidisciplinary field that aims to treat patients with trauma, spinal fusion and large bone defects. Cell-based bone tissue engineering encompasses the isolation of multipotent hMSCs from the bone marrow of the patient, in vit

  11. T Cell Receptor Engineering and Analysis Using the Yeast Display Platform.

    Science.gov (United States)

    Smith, Sheena N; Harris, Daniel T; Kranz, David M

    2015-01-01

    The αβ heterodimeric T cell receptor (TCR) recognizes peptide antigens that are transported to the cell surface as a complex with a protein encoded by the major histocompatibility complex (MHC). T cells thus evolved a strategy to sense these intracellular antigens, and to respond either by eliminating the antigen-presenting cell (e.g., a virus-infected cell) or by secreting factors that recruit the immune system to the site of the antigen. The central role of the TCR in the binding of antigens as peptide-MHC (pepMHC) ligands has now been studied thoroughly. Interestingly, despite their exquisite sensitivity (e.g., T cell activation by as few as 1-3 pepMHC complexes on a single target cell), TCRs are known to have relatively low affinities for pepMHC, with K D values in the micromolar range. There has been interest in engineering the affinity of TCRs in order to use this class of molecules in ways similar to now done with antibodies. By doing so, it would be possible to harness the potential of TCRs as therapeutics against a much wider array of antigens that include essentially all intracellular targets. To engineer TCRs, and to analyze their binding features more rapidly, we have used a yeast display system as a platform. Expression and engineering of a single-chain form of the TCR, analogous to scFv fragments from antibodies, allow the TCR to be affinity matured with a variety of possible pepMHC ligands. In addition, the yeast display platform allows one to rapidly generate TCR variants with diverse binding affinities and to analyze specificity and affinity without the need for purification of soluble forms of the TCRs. The present chapter describes the methods for engineering and analyzing single-chain TCRs using yeast display. PMID:26060072

  12. 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.

  13. 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. PMID:22065768

  14. 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.

  15. 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.

  16. Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape

    OpenAIRE

    Chouhan, Raghuraj Singh; Qureshi, Anjum; Kolkar Mohammed, Javed Hussain Niazi

    2015-01-01

    In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluoresc...

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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. PMID:21902543

  2. 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.

  3. 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.

  4. Xbp1-based engineering of secretory capacity enhances the productivity of Chinese hamster ovary cells.

    Science.gov (United States)

    Tigges, Marcel; Fussenegger, Martin

    2006-05-01

    A variety of successful transcription and translation engineering strategies implemented during the past decade have driven the specific productivity of mammalian cells to an apparent limit. Restricted post-translation competence has since been considered the major bottleneck preventing mammalian cells from fully exploiting their physiologic production capacity in a biopharmaceutical manufacturing scenario. Through ectopic expression of the human transcription factor Xbp1 (X-box-binding-protein 1), evolved to manage plasma cell differentiation and coordinate the unfolded protein response, we have specifically expanded the endoplasmic reticulum and the Golgi of transgenic Chinese hamster ovary (CHO-K1)-derived cell lines with a resulting increase in overall production capacity. Xbp-1-based engineering of secretory bottlenecks was compatible with a variety of different promoter–product gene configurations suggesting that Xbp-1 induces generic production increases in CHO-K1 cell derivatives. Secretion engineering, illustrated here by Xbp1-based reprogramming of the post-translational processing machinery, provides a first insight into mastering a major system bottleneck which impacts biopharmaceutical manufacturing of secreted protein therapeutics.

  5. 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.

  6. Engineering Salmonella as intracellular factory for effective killing of tumour cells.

    Science.gov (United States)

    Camacho, Eva María; Mesa-Pereira, Beatriz; Medina, Carlos; Flores, Amando; Santero, Eduardo

    2016-01-01

    Salmonella have many desirable properties as antitumour-agent due to its ability to proliferate inside tumours and induce tumour regression. Additionally, this bacterium can be genetically engineered to deliver therapeutic proteins intratumourally. The main limitation of this approach is the efficient release of therapeutic molecules from intratumoural bacteria. Here we have developed an inducible autolysis system based in the lysis operon of the lambda phage that, in response to anhydrotetracycline, lysates Salmonella thus releasing its content. The system was combined with a salicylate cascade system that allows efficient production of therapeutic molecules in response to aspirin and with a sifA mutation that liberates bacteria from the vacuoles to a cytosolic location. The combination of these three elements makes this strain a putative powerful instrument in cancer treatment. We have used this engineered strain for the intracellular production and delivery of Cp53 peptide. The engineered strain is able to sequentially produce and release the cytotoxic peptide while proliferating inside tumour cells, thus inducing host cell death. Our results show that temporal separation of protein production from protein release is essential to efficiently kill tumour cells. The combined system is a further step in the engineering of more efficient bacteria for cancer therapy. PMID:27464652

  7. 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.

  8. 不同表面处理方法对钛表面成骨细胞膜片 ALP活性的影响%Active Changes of ALP of Osteoblasts Cell Sheet with Different Treated Titanium Surfaces

    Institute of Scientific and Technical Information of China (English)

    毛久凤; 夏茜; 吴镭; 杨红; 周成菊; 方艺; 董强

    2016-01-01

    目的:探讨不同表面处理方法对钛表面的成骨细胞膜片碱性磷酸酶( ALP)活性的影响。方法:原代培养大鼠成骨细胞,通过形态学及ALP鉴定成骨细胞;以机械抛光处理的钛片为对照组,以棕刚玉颗粒喷砂材料处理的钛片为喷砂酸蚀( SLA)组,分别构建成骨细胞膜片,膜片连续培养1周或2周时,测量成骨细胞膜片中反映成骨效应的ALP活性的改变。结果:原代培养细胞ALP阳性,经形态及特性鉴定为成骨细胞;连续培养1周或2周时,SLA组ALP活性均高于对照组,差异有统计学意义( P<0.05);各组膜片ALP活性第1周高于第2周,差异有统计学意义( P<0.05)。结论:钛表面性质能够影响成骨细胞膜片的成骨分化能力。%[ Abstract]Objective:To study the ontogenesis of osteoblasts cell sheets with different treated surface of titanium. Methods:Primary cultured rat osteoblasts were identified through morphology observa-tion,alkaline phosphatase staining. Mechanically polished titanium sheets served as control group. The cell sheets were treated with brown fused alumina material as SLA group. Constructing osteoblast cell sheets respectively,and cultured successively for 1 or 2 weeks. Then,measuring changes of ALP activity. Results:Primary cultured cell ALP was positive,the morphology of cells conformed to the characteristics of osteoblasts. The alkaline phosphatase activity of the SLA group was higher than that of control group when cultured successively for 1 or 2 weeks,differences were statistically significant ( P<0 . 05 ). The alkaline phosphatase activity of the cell sheets formed in 1 st week was higher than that of 2nd week,differences were statistically significant(P<0. 05). Conclusion:The surface prop-erties of titanium could affect the osteogenic capacity of cell sheet.

  9. Nanotechnology versus stem cell engineering: in vitro comparison of neurite inductive potentials

    Directory of Open Access Journals (Sweden)

    Morano M

    2014-11-01

    Full Text Available Michela Morano,1,* Sandra Wrobel,2,3,* Federica Fregnan,1 Ofra Ziv-Polat,4 Abraham Shahar,4 Andreas Ratzka,2 Claudia Grothe,2,3 Stefano Geuna,1 Kirsten Haastert-Talini2,3 1Department of Clinical and Biological Sciences, Università Degli Studi di Torino, Orbassano, Piemonte, Italy; 2Institute of Neuroanatomy, Hannover Medical School, Hannover, Lower-Saxony, Germany; 3Center for Systems Neuroscience (ZSN, Hannover, Lower-Saxony, Germany; 4NVR Research Ltd, Ness-Ziona, Israel *These authors contributed equally to this work and share first authorship Purpose: Innovative nerve conduits for peripheral nerve reconstruction are needed in order to specifically support peripheral nerve regeneration (PNR whenever nerve autotransplantation is not an option. Specific support of PNR could be achieved by neurotrophic factor delivery within the nerve conduits via nanotechnology or stem cell engineering and transplantation.Methods: Here, we comparatively investigated the bioactivity of selected neurotrophic factors conjugated to iron oxide nanoparticles (np-NTFs and of bone marrow-derived stem cells genetically engineered to overexpress those neurotrophic factors (NTF-BMSCs. The neurite outgrowth inductive activity was monitored in culture systems of adult and neonatal rat sensory dorsal root ganglion neurons as well as in the cell line from rat pheochromocytoma (PC-12 cell sympathetic culture model system.Results: We demonstrate that np-NTFs reliably support numeric neurite outgrowth in all utilized culture models. In some aspects, especially with regard to their long-term bioactivity, np-NTFs are even superior to free NTFs. Engineered NTF-BMSCs proved to be less effective in induction of sensory neurite outgrowth but demonstrated an increased bioactivity in the PC-12 cell culture system. In contrast, primary nontransfected BMSCs were as effective as np-NTFs in sensory neurite induction and demonstrated an impairment of neuronal differentiation in the PC-12 cell

  10. 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.

  11. 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

  12. Metabolic engineering of Salmonella vaccine bacteria to boost human Vγ2Vδ2 T cell immunity.

    Science.gov (United States)

    Workalemahu, Grefachew; Wang, Hong; Puan, Kia-Joo; Nada, Mohanad H; Kuzuyama, Tomohisa; Jones, Bradley D; Jin, Chenggang; Morita, Craig T

    2014-07-15

    Human Vγ2Vδ2 T cells monitor isoprenoid metabolism by recognizing foreign (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), a metabolite in the 2-C-methyl-D-erythritol-4-phosphate pathway used by most eubacteria and apicomplexan parasites, and self isopentenyl pyrophosphate, a metabolite in the mevalonate pathway used by humans. Whereas microbial infections elicit prolonged expansion of memory Vγ2Vδ2 T cells, immunization with prenyl pyrophosphates or aminobisphosphonates elicit short-term Vγ2Vδ2 expansion with rapid anergy and deletion upon subsequent immunizations. We hypothesized that a live, attenuated bacterial vaccine that overproduces HMBPP would elicit long-lasting Vγ2Vδ2 T cell immunity by mimicking a natural infection. Therefore, we metabolically engineered the avirulent aroA(-) Salmonella enterica serovar Typhimurium SL7207 strain by deleting the gene for LytB (the downstream enzyme from HMBPP) and functionally complementing for this loss with genes encoding mevalonate pathway enzymes. LytB(-) Salmonella SL7207 had high HMBPP levels, infected human cells as efficiently as did the wild-type bacteria, and stimulated large ex vivo expansions of Vγ2Vδ2 T cells from human donors. Importantly, vaccination of a rhesus monkey with live lytB(-) Salmonella SL7207 stimulated a prolonged expansion of Vγ2Vδ2 T cells without significant side effects or anergy induction. These studies provide proof-of-principle that metabolic engineering can be used to derive live bacterial vaccines that boost Vγ2Vδ2 T cell immunity. Similar engineering of metabolic pathways to produce lipid Ags or B vitamin metabolite Ags could be used to derive live bacterial vaccine for other unconventional T cells that recognize nonpeptide Ags. PMID:24943221

  13. Human fetal bone cells associated with ceramic reinforced PLA scaffolds for tissue engineering.

    Science.gov (United States)

    Montjovent, Marc-Olivier; Mark, Silke; Mathieu, Laurence; Scaletta, Corinne; Scherberich, Arnaud; Delabarde, Claire; Zambelli, Pierre-Yves; Bourban, Pierre-Etienne; Applegate, Lee Ann; Pioletti, Dominique P

    2008-03-01

    Fetal bone cells were shown to have an interesting potential for therapeutic use in bone tissue engineering due to their rapid growth rate and their ability to differentiate into mature osteoblasts in vitro. We describe hereafter their capability to promote bone repair in vivo when combined with porous scaffolds based on poly(l-lactic acid) (PLA) obtained by supercritical gas foaming and reinforced with 5 wt.% beta-tricalcium phosphate (TCP). Bone regeneration was assessed by radiography and histology after implantation of PLA/TCP scaffolds alone, seeded with primary fetal bone cells, or coated with demineralized bone matrix. Craniotomy critical size defects and drill defects in the femoral condyle in rats were employed. In the cranial defects, polymer degradation and cortical bone regeneration were studied up to 12 months postoperatively. Complete bone ingrowth was observed after implantation of PLA/TCP constructs seeded with human fetal bone cells. Further tests were conducted in the trabecular neighborhood of femoral condyles, where scaffolds seeded with fetal bone cells also promoted bone repair. We present here a promising approach for bone tissue engineering using human primary fetal bone cells in combination with porous PLA/TCP structures. Fetal bone cells could be selected regarding osteogenic and immune-related properties, along with their rapid growth, ease of cell banking and associated safety. PMID:18178142

  14. 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. PMID:27622532

  15. A review of decellularized stem cell matrix: a novel cell expansion system for cartilage tissue engineering

    OpenAIRE

    M Pei; Li JT; Shoukry, M; Y Zhang

    2011-01-01

    Cell-based therapy is a promising biological approach for the treatment of cartilage defects. Due to the small size of autologous cartilage samples available for cell transplantation in patients, cells need to be expanded to yield a sufficient cell number for cartilage repair. However, chondrocytes and adult stem cells tend to become replicatively senescent once they are expanded on conventional plastic flasks. Many studies demonstrate that the loss of cell properties is concomitant with the ...

  16. 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....

  17. Thermodynamic Analysis of a Woodchips Gasification Integrated with Solid Oxide Fuel Cell and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    Integrated gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power application is analysed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas which is utilized for feeding the SOFC stacks for electricity...... production. Unreacted hydrocarbons after 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. The domestic hot water is used as heat sink for the Stirling engine. A complete balance of plant is designed...... and suggested. Thermodynamic analysis shows that a thermal efficiency of 42.4% based on LHV (lower heating value) can be achieved. Different parameter studies are performed to analysis system behaviour under different conditions. The analysis show that increasing fuel mass flow from the design point results...

  18. 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...

  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. Enhanced cell-material interactions through the biofunctionalization of polymeric surfaces with engineered peptides.

    Science.gov (United States)

    Punet, Xavier; Mauchauffé, Rodolphe; Giannotti, Marina I; Rodríguez-Cabello, José C; Sanz, Fausto; Engel, Elisabeth; Mateos-Timoneda, Miguel A; Planell, Josep A

    2013-08-12

    Research on surface modification of polymeric materials to guide the cellular activity in biomaterials designed for tissue engineering applications has mostly focused on the use of natural extracellular matrix (ECM) proteins and short peptides, such as RGD. However, the use of engineered proteins can gather the advantages of these strategies and avoid the main drawbacks. In this study, recombinant engineered proteins called elastin-like recombinamers (ELRs) have been used to functionalize poly(lactic) acid (PLA) model surfaces. The structure of the ELRs has been designed to include the integrin ligand RGDS and the cross-linking module VPGKG. Surface functionalization has been characterized and optimized by means of ELISA and atomic force microscopy (AFM). The results suggest that ELR functionalization creates a nonfouling canvas able to restrict unspecific adsorption of proteins. Moreover, AFM analysis reveals the conformation and disposition of ELRs on the surface. Biological performance of PLA surfaces functionalized with ELRs has been studied and compared with the use of short peptides. Cell response has been assessed for different functionalization conditions in the presence and absence of the bovine serum albumin (BSA) protein, which could interfere with the surface-cell interaction by adsorbing on the interface. Studies have shown that ELRs are able to elicit higher rates of cell attachment, stronger cell anchorages and faster levels of proliferation than peptides. This work has demonstrated that the use of engineered proteins is a more efficient strategy to guide the cellular activity than the use of short peptides, because they not only allow for better cell attachment and proliferation, but also can provide more complex properties such as the creation of nonfouling surfaces. PMID:23805782

  1. Time-lapse Imaging of Primary Preneoplastic Mammary Epithelial Cells Derived from Genetically Engineered Mouse Models of Breast Cancer

    OpenAIRE

    Nakles, Rebecca E.; Millman, Sarah L.; Cabrera, M. Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S.; Schroeder, Timm; Furth, Priscilla A.

    2013-01-01

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without...

  2. 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.

  3. Thermoforming of foam sheet

    OpenAIRE

    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 the sheet in the required form on the mould. This production method appears to be a very sensitive process with respect to e.g. the sheet temperature, the pressures applied and the cooling time. Mor...

  4. Perforating Thin Metal Sheets

    Science.gov (United States)

    Davidson, M. E.

    1985-01-01

    Sheets only few mils thick bonded together, punched, then debonded. Three-step process yields perforated sheets of metal. (1): Individual sheets bonded together to form laminate. (2): laminate perforated in desired geometric pattern. (3): After baking, laminate separates into individual sheets. Developed for fabricating conductive layer on blankets that collect and remove ions; however, perforated foils have other applications - as conductive surfaces on insulating materials; stiffeners and conductors in plastic laminates; reflectors in antenna dishes; supports for thermal blankets; lightweight grille cover materials; and material for mockup of components.

  5. Ice sheet in peril

    OpenAIRE

    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 ...

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Hepatic tissue engineering: from transplantation to customized cell-based liver directed therapies from the laboratory

    OpenAIRE

    Fiegel, Henning C; Kaufmann, Peter M; Bruns, Helge; Kluth, Dietrich; Horch, Raymund E.; Vacanti, Joseph P.; Kneser, Ulrich

    2008-01-01

    Abstract Today, liver transplantation is still the only curative treatment for liver failure due to end-stage 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, for example, liver tissue engineering, are under investigation with the aim that in future an artificial liver tissue could be created and be used for the r...

  12. Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

    OpenAIRE

    Dirk Henrich; René Verboket; Alexander Schaible; Kerstin Kontradowitz; Elsie Oppermann; Brune, Jan C; Christoph Nau; Simon Meier; Halvard Bonig; Ingo Marzi; Caroline Seebach

    2015-01-01

    Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or ...

  13. Human fetal bone cells associated with ceramic reinforced PLA scaffolds for tissue engineering

    OpenAIRE

    Montjovent, Marc-Olivier; Mark, Silke; Mathieu, Laurence; Scaletta, Corinne; Scherberich, Arnaud; Delabarde, Claire; Zambelli, Pierre-Yves; Bourban, Pierre-Etienne; Applegate, Lee Ann; Pioletti, Dominique P.

    2008-01-01

    Fetal bone cells were shown to have an interesting potential for therapeutic use in bone tissue engineering due to their rapid growth rate and their ability to differentiate into mature osteoblasts in vitro. We describe hereafter their capability to promote bone repair in vivo when combined with porous scaffolds based on poly(L-lactic acid) (PLA) obtained by supercritical gas foaming and reinforced with 5 wt% β-tricalcium phosphate (TCP). Bone regeneration was assessed by radiogra...

  14. Immunotoxicological impact of engineered nanomaterial exposure: mechanisms of immune cell modulation

    OpenAIRE

    WANG, XIAOJIA; Reece, Shaun P.; Brown, Jared M.

    2013-01-01

    Engineered nanomaterials (ENM) are increasingly being utilized in many consumer products and various medical applications thereby leading to the potentiality of increased human exposures. Assessment of the adverse effects on the immune system is an important component for evaluating the overall health and safety of ENM. Tasked with eliminating pathogens and removing cancerous cells, the immune system is constantly functioning to maintain homeostasis. Small modifications to the immune system w...

  15. Preface to Special Topic: Microfluidics in cell biology and tissue engineering

    OpenAIRE

    Dokmeci, Mehmet R.; Khademhosseini, Ali

    2011-01-01

    In this special issue of Biomicrofluidics, a wide variety of applications of microfluidics to tissue engineering and cell biology are presented. The articles illustrate the benefits of using microfluidics for controlling the cellular environment in a precise yet high rate manner using minimum reagents. The topic is very timely and takes a stab at portraying a glimpse of what is to come in this exciting and emerging field of research.

  16. Epidermal stem cells and skin tissue engineering in hair follicle regeneration

    OpenAIRE

    Balañá, María Eugenia; Charreau, Hernán Eduardo; Leirós, Gustavo José

    2015-01-01

    The reconstitution of a fully organized and functional hair follicle from dissociated cells propagated under defined tissue culture conditions is a challenge still pending in tissue engineering. The loss of hair follicles caused by injuries or pathologies such as alopecia not only affects the patients’ psychological well-being, but also endangers certain inherent functions of the skin. It is then of great interest to find different strategies aiming to regenerate or neogenerate the hair folli...

  17. Solving cell infiltration limitations of electrospun nanofiber meshes for tissue engineering applications

    OpenAIRE

    Guimarães, Ana; Martins, Albino; Pinho, Elisabete D.; Faria, Susana; Reis, R. L.; Neves, N. M.

    2010-01-01

    AIM: Utilize the dual composition strategy to increase the pore size and solve the low cell infiltration capacity on random nanofiber meshes, an intrinsic limitation of electrospun scaffolds for tissue engineering applications. MATERIALS & METHODS: Polycaprolactone and poly(ethylene oxide) solutions were electrospun simultaneously to obtain a dual composition nanofiber mesh. Selective dissolution of the poly(ethylene oxide) nanofiber fraction was performed. The biologic performance of these e...

  18. 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.

  19. In vitro evaluation of cytotoxicity of engineered carbon nanotubes in selected human cell lines

    International Nuclear Information System (INIS)

    In this study, we used a systematic approach to study and compare the in vitro cytotoxicity of selected engineered carbon nanotubes (CNTs) to test cell lines including human skin keratinocytes, lung cells and lymphocytes. Results of fluorescein diacetate (FDA) uptake in T4 lymphocyte A3 cells indicated cytotoxicity caused by single-walled carbon nanotubes (SWCNTs) at concentrations of 2, 5 and 10 ppm. At 2 ppm, the SWCNT treatment group retained 71.3% viability compared to the PBS control group. At 10 ppm, cellular viability further decreased to 56.5% of the PBS control group. In the skin keratinocyte HaCaT cells and lung MSTO-211H cells, the SWCNT did not demonstrate any cytotoxicity at concentrations of 2 and 5 ppm but slightly inhibited HaCaT cells and caused significant toxicity to MSTO-211H cells at 10 ppm. Multi-walled carbon nanotube (MWCNT) testing showed significant cytotoxicity to A3 cells in a dose-dependent manner. At 10 ppm the viability of the cells decreased to 89.1% compared to the PBS control. In MSTO-211H cells, MWCNT caused significant toxicity at concentrations of 2 ppm and higher. By comparison, HaCaT cells were inhibited significantly only at 10 ppm. Overall, the test CNTs inhibited cellular viabilities in a concentration, cell type, and CNT type-dependent pattern. The viabilities of the MWCNT-impacted cells are higher than the corresponding SWCNT groups. We speculate that on a per volume basis, the greater availability of defects and contaminants for cellular interaction may contribute to the higher cytotoxicity of SWCNT in this study. The interaction between the SWCNTs and A3 lymphocytes was also observed by scanning electron microscopy. The mechanism for causing cell death in this study was attributed to apoptosis and necrosis after physical penetration by CNTs and oxidative stress via formation of reactive oxygen species.

  20. 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.

  1. 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 Escherichia coli known as Type 1 fimbriae that enable natural adhesion to glycosylated substrates. Sequence alterations within the fimbrial gene cluster were found to be well-tolerated, evidenced by tagging the fimbriae with peptide-based probes. As a further development, fimbriae tips could be reconfigured to, in turn, alter cell binding. In particular, the fimbriae were fused with a genetically optimized peptide-for-inorganics to enable metal binding. This work established methodologies to systematically survey cell adhesion properties across a suite of fimbriae-modified cell types as well as to direct patterned cell adhesion. Cell types were further customized for added complexity including turning on secondary gene expression and binding to gold surfaces. The former demonstrates potential for programmable gene switches and the latter for interfacing biology with inorganic materials. In general, the incorporation of 'programmed' cells into devices can be used to provide the feature of dynamic and automated cell response. The outcomes of this study are foundational toward the critical feature of deliberate positioning of cells as configurable biocomponentry. Overall, cellular integration into bioMEMs will yield advanced sensing and actuation.

  2. Tissue engineering approaches for studying the effect of biochemical and physiological stimuli on cell behavior

    Science.gov (United States)

    Jimenez Vergara, Andrea Carolina

    Tissue engineering (TE) approaches have emerged as an alternative to traditional tissue and organ replacements. The aim of this work was to contribute to the understanding of the effects of cell-material and endothelial cell (EC) paracrine signaling on cell responses using poly(ethylene glycol) diacrylate (PEGDA) hydrogels as a material platform. Three TE applications were explored. First, the effect of glycosaminoglycan (GAG) identity was evaluated for vocal fold restoration. Second, the influence of GAG identity was explored and a novel approach for stable endothelialization was developed for vascular graft applications. Finally, EC paracrine signaling in the presence of cyclic stretch, and hydrophobicity and inorganic content were studied for osteogenic applications. In terms of vocal fold restoration, it was found that vocal fold fibroblast (VFF) phenotype and extracellular matrix (ECM) production were impacted by GAG identity. VFF phenotype was preserved in long-term cultured hydrogels containing high molecular weight hyaluronan (HAHMW). Furthermore, collagen I deposition, fibronectin production and smooth muscle α-actin (SM-α-actin) expression in PEG-HA, PEG-chondroitin sulfate C and PEG-heparan sulfate (HS) gels suggest that CSC and HS may be undesirable for vocal fold implants. Regarding vascular graft applications, the impact of GAG identity on smooth muscle cell (SMC) foam cell formation was explored. Results support the increasing body of literature that suggests a critical role for dermatan sulfate (DS)-bearing proteoglycans in early atherosclerosis. In addition, an approach for fabricating bi-layered tissue engineering vascular grafts (TEVGs) with stable endothelialization was validated using PEGDA as an intercellular “cementing” agent between adjacent endothelial cells (ECs). Finally, mesenchymal stem cell (MSC) differentiation toward osteogenic like cells was evaluated. ECM and cell phenotypic data showed that elevated scaffold inorganic

  3. 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

  4. From Single Cells to Engineered and Explanted Tissues: New Perspectives in Bacterial Infection Biology.

    Science.gov (United States)

    Bergmann, Simone; Steinert, Michael

    2015-01-01

    Cell culture techniques are essential for studying host-pathogen interactions. In addition to the broad range of single cell type-based two-dimensional cell culture models, an enormous amount of coculture systems, combining two or more different cell types, has been developed. These systems enable microscopic visualization and molecular analyses of bacterial adherence and internalization mechanisms and also provide a suitable setup for various biochemical, immunological, and pharmacological applications. The implementation of natural or synthetical scaffolds elevated the model complexity to the level of three-dimensional cell culture. Additionally, several transwell-based cell culture techniques are applied to study bacterial interaction with physiological tissue barriers. For keeping highly differentiated phenotype of eukaryotic cells in ex vivo culture conditions, different kinds of microgravity-simulating rotary-wall vessel systems are employed. Furthermore, the implementation of microfluidic pumps enables constant nutrient and gas exchange during cell cultivation and allows the investigation of long-term infection processes. The highest level of cell culture complexity is reached by engineered and explanted tissues which currently pave the way for a more comprehensive view on microbial pathogenicity mechanisms. PMID:26404465

  5. Engineered Nanoparticles as Potential Food Contaminants and Their Toxicity to Caco-2 Cells.

    Science.gov (United States)

    Mao, Xiaomo; Nguyen, Trang H D; Lin, Mengshi; Mustapha, Azlin

    2016-08-01

    Engineered nanoparticles (ENPs), such as metallic or metallic oxide nanoparticles (NPs), have gained much attention in recent years. Increasing use of ENPs in various areas may lead to the release of ENPs into the environment and cause the contamination of agricultural and food products by ENPs. In this study, we selected two important ENPs (zinc oxide [ZnO] and silver [Ag] NPs) as potential food contaminants and investigated their toxicity via an in vitro model using Caco-2 cells. The physical properties of ENPs and their effects on Caco-2 cells were characterized by electron microscopy and energy dispersive X-ray spectroscopic (EDS) techniques. Results demonstrate that a significant inhibition of cell viability was observed after a 24-h of exposure of Caco-2 cells to 3-, 6-, and 12-mM ZnO NPs or 0.5-, 1.5-, and 3-mM Ag NPs. The noticeable changes of cells include the alteration in cell shape, abnormal nuclear structure, membrane blebbing, and cytoplasmic deterioration. The toxicity of ZnO NPs, but not that of Ag NPs after exposure to simulated gastric fluid, significantly decreased. Scanning transmission electron microscopy shows that ZnO and Ag NPs penetrated the membrane of Caco-2 cells. EDS results also confirm the presence of NPs in the cytoplasm of the cells. This study demonstrates that ZnO and Ag NPs have cytotoxic effects and can inhibit the growth of Caco-2 cells.

  6. Engineered Nanoparticles as Potential Food Contaminants and Their Toxicity to Caco-2 Cells.

    Science.gov (United States)

    Mao, Xiaomo; Nguyen, Trang H D; Lin, Mengshi; Mustapha, Azlin

    2016-08-01

    Engineered nanoparticles (ENPs), such as metallic or metallic oxide nanoparticles (NPs), have gained much attention in recent years. Increasing use of ENPs in various areas may lead to the release of ENPs into the environment and cause the contamination of agricultural and food products by ENPs. In this study, we selected two important ENPs (zinc oxide [ZnO] and silver [Ag] NPs) as potential food contaminants and investigated their toxicity via an in vitro model using Caco-2 cells. The physical properties of ENPs and their effects on Caco-2 cells were characterized by electron microscopy and energy dispersive X-ray spectroscopic (EDS) techniques. Results demonstrate that a significant inhibition of cell viability was observed after a 24-h of exposure of Caco-2 cells to 3-, 6-, and 12-mM ZnO NPs or 0.5-, 1.5-, and 3-mM Ag NPs. The noticeable changes of cells include the alteration in cell shape, abnormal nuclear structure, membrane blebbing, and cytoplasmic deterioration. The toxicity of ZnO NPs, but not that of Ag NPs after exposure to simulated gastric fluid, significantly decreased. Scanning transmission electron microscopy shows that ZnO and Ag NPs penetrated the membrane of Caco-2 cells. EDS results also confirm the presence of NPs in the cytoplasm of the cells. This study demonstrates that ZnO and Ag NPs have cytotoxic effects and can inhibit the growth of Caco-2 cells. PMID:27505352

  7. Interface Engineering of High Efficiency Organic-Silicon Heterojunction Solar Cells.

    Science.gov (United States)

    Yang, Lixia; Liu, Yaoping; Chen, Wei; Wang, Yan; Liang, Huili; Mei, Zengxia; Kuznetsov, Andrej; Du, Xiaolong

    2016-01-13

    Insufficient interface conformity is a challenge faced in hybrid organic-silicon heterojunction solar cells because of using conventional pyramid antireflection texturing provoking the porosity of interface. In this study, we tested alternative textures, in particular rounded pyramids and inverted pyramids to compare the performance. It was remarkably improved delivering 7.61%, 8.91% and 10.04% efficiency employing conventional, rounded, and inverted pyramids, respectively. The result was interpreted in terms of gradually improving conformity of the Ag/organic/silicon interface, together with the gradually decreasing serial resistance. Altogether, the present data may guide further efforts arising the interface engineering for mastering high efficient heterojunction solar cells. PMID:26701061

  8. Systemic treatment with CAR-engineered T cells against PSCA delays subcutaneous tumor growth and prolongs survival of mice

    International Nuclear Information System (INIS)

    Adoptive transfer of T cells genetically engineered with a chimeric antigen receptor (CAR) has successfully been used to treat both chronic and acute lymphocytic leukemia as well as other hematological cancers. Experimental therapy with CAR-engineered T cells has also shown promising results on solid tumors. The prostate stem cell antigen (PSCA) is a protein expressed on the surface of prostate epithelial cells as well as in primary and metastatic prostate cancer cells and therefore a promising target for immunotherapy of prostate cancer. We developed a third-generation CAR against PSCA including the CD28, OX-40 and CD3 ζ signaling domains. T cells were transduced with a lentivirus encoding the PSCA-CAR and evaluated for cytokine production (paired Student’s t-test), proliferation (paired Student’s t-test), CD107a expression (paired Student’s t-test) and target cell killing in vitro and tumor growth and survival in vivo (Log-rank test comparing Kaplan-Meier survival curves). PSCA-CAR T cells exhibit specific interferon (IFN)-γ and interleukin (IL)-2 secretion and specific proliferation in response to PSCA-expressing target cells. Furthermore, the PSCA-CAR-engineered T cells efficiently kill PSCA-expressing tumor cells in vitro and systemic treatment with PSCA-CAR-engineered T cells significantly delays subcutaneous tumor growth and prolongs survival of mice. Our data confirms that PSCA-CAR T cells may be developed for treatment of prostate cancer

  9. Engineered heart tissues and induced pluripotent stem cells: Macro- and microstructures for disease modeling, drug screening, and translational studies.

    Science.gov (United States)

    Tzatzalos, Evangeline; Abilez, Oscar J; Shukla, Praveen; Wu, Joseph C

    2016-01-15

    Engineered heart tissue has emerged as a personalized platform for drug screening. With the advent of induced pluripotent stem cell (iPSC) technology, patient-specific stem cells can be developed and expanded into an indefinite source of cells. Subsequent developments in cardiovascular biology have led to efficient differentiation of cardiomyocytes, the force-producing cells of the heart. iPSC-derived cardiomyocytes (iPSC-CMs) have provided potentially limitless quantities of well-characterized, healthy, and disease-specific CMs, which in turn has enabled and driven the generation and scale-up of human physiological and disease-relevant engineered heart tissues. The combined technologies of engineered heart tissue and iPSC-CMs are being used to study diseases and to test drugs, and in the process, have advanced the field of cardiovascular tissue engineering into the field of precision medicine. In this review, we will discuss current developments in engineered heart tissue, including iPSC-CMs as a novel cell source. We examine new research directions that have improved the function of engineered heart tissue by using mechanical or electrical conditioning or the incorporation of non-cardiomyocyte stromal cells. Finally, we discuss how engineered heart tissue can evolve into a powerful tool for therapeutic drug testing.

  10. Comparative study on seeding methods of human bone marrow stromal cells in bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    齐欣; 刘建国; 常颖; 徐莘香

    2004-01-01

    Background In general the traditional static seeding method has its limitation while the dynamic seeding method reveals its advantages over traditional static method. We compared static and dynamic seeding method for human bone marrow stromal cells (hBMSCs) in bone tissue engineering.Methods DNA assay was used for detecting the maximal initial seeding concentration for static seeding. Dynamic and static seeding methods were compared, when scaffolds were loaded with hBMSCs at this maximal initial cell seeding concentration. Histology and scanning electron microscope (SEM) were examined to evaluate the distribution of cells inside the constructs. Markers encoding osteogenic genes were measured by fluorescent RT-PCR. The protocol for dynamic seeding of hBMSCs was also investigated.Results DNA assay showed that the static maximal initial seeding concentration was lower than that in dynamic seeding. Histology and SEM showed even distribution and spread of cells in the dynamically seeded constructs, while their statically seeded counterparts showed cell aggregation.Fluorescent RT-PCR again showed stronger osteogenic potential of dynamically seeded constructs.Conclusion dynamic seeding of hBMSCs is a promising technique in bone tissue engineering.

  11. Current and future regenerative medicine - principles, concepts, and therapeutic use of stem cell therapy and tissue engineering in equine medicine

    DEFF Research Database (Denmark)

    Koch, Thomas Gadegaard; Berg, Lise Charlotte; Betts, Dean H.

    2009-01-01

    This paper provides a bird's-eye perspective of the general principles of stem-cell therapy and tissue engineering; it relates comparative knowledge in this area to the current and future status of equine regenerative medicine.The understanding of equine stem cell biology, biofactors, and scaffolds...... mesenchymal stromal cells, unless there is proof that they exhibit the fundamental in vivo characteristics of pluripotency and the ability to self-renew. That said, these cells from various tissues hold great promise for therapeutic use in horses. The 3 components of tissue engineering - cells, biological...

  12. Fuel cells science and engineering. Materials, processes, systems and technology. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Stolten, Detlef; Emonts, Bernd (eds.) [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF), Brennstoffzellen (IEF-3)

    2012-07-01

    The second volume is divided in four parts and 19 chapters. It is structured as follows: PART V: Modeling and Simulation. Chapter 23: Messages from Analytical Modeling of Fuel Cells (Andrei Kulikovsky); 24: Stochastic Modeling of Fuel-Cell Components (Ralf Thiedmann, Gerd Gaiselmann, Werner Lehnert and Volker Schmidt); 25: Computational Fluid Dynamic Simulation Using Supercomputer Calculation Capacity (Ralf Peters and Florian Scharf); 26 Modeling Solid Oxide Fuel Cells from the Macroscale to the Nanoscale (Emily M. Ryan and Mohammad A. Khaleel); 27: Numerical Modeling of the Thermomechanically Induced Stress in Solid Oxide Fuel Cells (Murat Peksen); 28: Modeling of Molten Carbonate Fuel Cells (Peter Heidebrecht, Silvia Piewek and Kai Sundmacher); Chapter 29: High-Temperature Polymer Electrolyte Fuel-Cell Modeling (Uwe Reimer); Chapter 30: Modeling of Polymer Electrolyte Membrane Fuel-Cell Components (Yun Wang and Ken S. Chen); 31: Modeling of Polymer Electrolyte Membrane Fuel Cells and Stacks (Yun Wang and Ken S. Chen). PART VI: Balance of Plant Design and Components. Chapter 32: Principles of Systems Engineering (Ludger Blum, Ralf Peters and Remzi Can Samsun); 33: System Technology for Solid Oxide Fuel Cells (Nguyen Q. Minh); 34: Desulfurization for Fuel-Cell Systems (Joachim Pasel and Ralf Peters); 35: Design Criteria and Components for Fuel Cell Powertrains (Lutz Eckstein and Bruno Gnoerich); 36: Hybridization for Fuel Cells (Joerg Wilhelm). PART VII: Systems Verification and Market Introduction. Chapter 37: Off-Grid Power Supply and Premium Power Generation (Kerry-Ann Adamson); 38: Demonstration Projects and Market Introduction (Kristin Deason). PART VIII: Knowledge Distribution and Public Awareness. Chapter 39: A Sustainable Framework for International Collaboration: the IEA HIA and Its Strategic Plan for 2009-2015 (Mary-Rose de Valladares); 40: Overview of Fuel Cell and Hydrogen Organizations and Initiatives Worldwide (Bernd Emonts) 41: Contributions for

  13. A Versatile System for USER Cloning-Based Assembly of Expression Vectors for Mammalian Cell Engineering

    DEFF Research Database (Denmark)

    Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Petersen, Maja Borup Kjær;

    2014-01-01

    A new versatile mammalian vector system for protein production, cell biology analyses, and cell factory engineering was developed. The vector system applies the ligation-free uracil-excision based technique – USER cloning – to rapidly construct mammalian expression vectors of multiple DNA fragments...... efficiency above 90%. The functionality of basic vectors for FAST assembly was tested and validated by transient expression of fluorescent model proteins in CHO, U-2-OS and HEK293 cell lines. In this test, we included many of the most common vector elements for heterologous gene expression in mammalian cells...... and with maximum flexibility, both for choice of vector backbone and cargo. The vector system includes a set of basic vectors and a toolbox containing a multitude of DNA building blocks including promoters, terminators, selectable marker- and reporter genes, and sequences encoding an internal ribosome entry site...

  14. Infertility Fact Sheet

    Science.gov (United States)

    ... Home > ePublications > Our ePublications > Infertility fact sheet ePublications Infertility fact sheet This information in Spanish (en español) ... to the fallopian tube instead of the uterus. Gamete intrafallopian transfer (GIFT) involves transferring eggs and sperm into the ...

  15. 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

  16. 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

  17. Heterojunction solar cell with 6% efficiency based on an n-type aluminum-gallium-oxide thin film and p-type sodium-doped Cu2O sheet

    Science.gov (United States)

    Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

    2015-02-01

    In this paper, we describe efforts to enhance the efficiency of Cu2O-based heterojunction solar cells fabricated with an aluminum-gallium-oxide (Al-Ga-O) thin film as the n-type layer and a p-type sodium (Na)-doped Cu2O (Cu2O:Na) sheet prepared by thermally oxidizing copper sheets. The optimal Al content [X; Al/(Ga + Al) atomic ratio] of an AlX-Ga1-X-O thin-film n-type layer was found to be approximately 2.5 at. %. The optimized resistivity was approximately 15 Ω cm for n-type AlX-Ga1-X-O/p-type Cu2O:Na heterojunction solar cells. A MgF2/AZO/Al0.025-Ga0.975-O/Cu2O:Na heterojunction solar cell with 6.1% efficiency was fabricated using a 60-nm-thick n-type oxide thin-film layer and a 0.2-mm-thick Cu2O:Na sheet with the optimized resistivity.

  18. High-throughput transfection and engineering of primary cells and cultured cell lines - an invaluable tool for research as well as drug development.

    Science.gov (United States)

    Müller-Hartmann, Herbert; Faust, Nicole; Kazinski, Michael; Kretzschmar, Titus

    2007-11-01

    The manipulation of eukaryotic cells by introducing nucleic acids and other substrates using chemical, physical or viral methods is one of the ground-breaking tools in the life sciences. Changes in the molecular equipment of a cell induced by introducing different molecules not only enable the dissection of signal transduction and metabolic pathways, but also allow the exploitation of engineered cells as bio-factories for the production of proteins in the processes of target research and drug development. In addition to the application of engineered cells for modern cell-based assays, medically relevant engineered cells can be used in clinical settings for adoptive immunotherapy or gene therapy. With the advent of methods exploiting RNA interference (RNAi), gene identification and functional validation in eukaryotic cells have clearly become one of the most exciting methods in life sciences during the past few years. To accelerate research and development in these areas, high-quality, high-throughput approaches (i.e., using sample formats of at least 96 wells) for cell engineering are needed with increasing demand. Recent developments, especially in the field of electroporation, now allow the efficient, high-throughput engineering of virtually any cell type, including primary cells, many of which were previously considered difficult or even impossible to transfect. Primary cells freshly isolated from native tissues are gaining more and more interest, as data obtained with these cells are considered to be of higher physiological relevance than data obtained with immortalized cell lines that have been cultured for extensive periods. In this review, the various methods for cell engineering (with focus on higher eukaryotic cells) are summarized and their impact for high-throughput applications in research and drug development is discussed.

  19. A special issue on reviews in biomedical applications of nanomaterials, tissue engineering, stem cells, bioimaging, and toxicity.

    Science.gov (United States)

    Nalwa, Hari Singh

    2014-10-01

    This second special issue of the Journal of Biomedical Nanotechnology in a series contains another 30 state-of-the-art reviews focused on the biomedical applications of nanomaterials, biosensors, bone tissue engineering, MRI and bioimaging, single-cell detection, stem cells, endothelial progenitor cells, toxicity and biosafety of nanodrugs, nanoparticle-based new therapeutic approaches for cancer, hepatic and cardiovascular disease.

  20. Human amniotic fluid derived cells can competently substitute dermal fibroblasts in a tissue-engineered dermo-epidermal skin analog

    NARCIS (Netherlands)

    Hartmann-Fritsch, Fabienne; Hosper, Nynke; Luginbuehl, Joachim; Biedermann, Thomas; Reichmann, Ernst; Meuli, Martin

    2013-01-01

    Human amniotic fluid comprises cells with high differentiation capacity, thus representing a potential cell source for skin tissue engineering. In this experimental study, we investigated the ability of human amniotic fluid derived cells to substitute dermal fibroblasts and support epidermis formati

  1. A special issue on reviews in biomedical applications of nanomaterials, tissue engineering, stem cells, bioimaging, and toxicity.

    Science.gov (United States)

    Nalwa, Hari Singh

    2014-10-01

    This second special issue of the Journal of Biomedical Nanotechnology in a series contains another 30 state-of-the-art reviews focused on the biomedical applications of nanomaterials, biosensors, bone tissue engineering, MRI and bioimaging, single-cell detection, stem cells, endothelial progenitor cells, toxicity and biosafety of nanodrugs, nanoparticle-based new therapeutic approaches for cancer, hepatic and cardiovascular disease. PMID:25992404

  2. Fibronectin-Alginate microcapsules improve cell viability and protein secretion of encapsulated Factor IX-engineered human mesenchymal stromal cells.

    Science.gov (United States)

    Sayyar, Bahareh; Dodd, Megan; Marquez-Curtis, Leah; Janowska-Wieczorek, Anna; Hortelano, Gonzalo

    2015-01-01

    Continuous delivery of proteins by engineered cells encapsu-lated in biocompatible polymeric microcapsules is of considerable therapeutic potential. However, this technology has not lived up to expectations due to inadequate cell--matrix interactions and subsequent cell death. In this study we hypoth-esize that the presence of fibronectin in an alginate matrix may enhance the viability and functionality of encapsulated human cord blood-derived mesenchymal stromal cells (MSCs) expressing the human Factor IX (FIX) gene. MSCs were encapsulated in alginate-PLL microcapsules containing 10, 100, or 500 μg/ml fibronectin to ameliorate cell survival. MSCs in microcapsules with 100 and 500 μg/ml fibronectin demonstrated improved cell viability and proliferation and higher FIX secretion compared to MSCs in non-supplemented microcapsules. In contrast, 10 μg/ml fibronectin did not significantly affect the viability and protein secretion from the encapsulated cells. Differentiation studies demonstrated osteogenic (but not chondrogenic or adipogenic) differentiation capability and efficient FIX secretion of the enclosed MSCs in the fibronectin-alginate suspension culture. Thus, the use of recombinant MSCs encapsulated in fibronectin-alginate microcapsules in basal or osteogenic cultures may be of practical use in the treatment of hemophilia B. PMID:24564349

  3. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells.

    Science.gov (United States)

    Yin, Wei; Pan, Lijia; Yang, Tingbin; Liang, Yongye

    2016-01-01

    Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE) and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ) perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed. PMID:27347923

  4. Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Wei Yin

    2016-06-01

    Full Text Available Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed.

  5. Co-incident insertion enables high efficiency genome engineering in mouse embryonic stem cells

    Science.gov (United States)

    Shy, Brian R.; MacDougall, Matthew S.; Clarke, Ryan; Merrill, Bradley J.

    2016-01-01

    CRISPR/Cas9 nucleases have enabled powerful, new genome editing capabilities; however, the preponderance of non-homologous end joining (NHEJ) mediated repair events over homology directed repair (HDR) in most cell types limits the ability to engineer precise changes in mammalian genomes. Here, we increase the efficiency of isolating precise HDR-mediated events in mouse embryonic stem (ES) cells by more than 20-fold through the use of co-incidental insertion (COIN) of independent donor DNA sequences. Analysis of on:off-target frequencies at the Lef1 gene revealed that bi-allelic insertion of a PGK-Neo cassette occurred more frequently than expected. Using various selection cassettes targeting multiple loci, we show that the insertion of a selectable marker at one control site frequently coincided with an insertion at an unlinked, independently targeted site, suggesting enrichment of a sub-population of HDR-proficient cells. When individual cell events were tracked using flow cytometry and fluorescent protein markers, individual cells frequently performed either a homology-dependent insertion event or a homology-independent event, but rarely both types of insertions in a single cell. Thus, when HDR-dependent selection donors are used, COIN enriches for HDR-proficient cells among heterogeneous cell populations. When combined with a self-excising selection cassette, COIN provides highly efficient and scarless genome editing. PMID:27484482

  6. Engineered Microenvironments for the Maturation and Observation of Human Embryonic Stem Cell Derived Cardiomyocytes

    Science.gov (United States)

    Salick, Max R.

    The human heart is a dynamic system that undergoes substantial changes as it develops and adapts to the body's growing needs. To better understand the physiology of the heart, researchers have begun to produce immature heart muscle cells, or cardiomyocytes, from pluripotent stem cell sources with remarkable efficiency. These stem cell-derived cardiomyocytes hold great potential in the understanding and treatment of heart disease; however, even after prolonged culture, these cells continue to exhibit an immature phenotype, as indicated by poor sarcomere organization and calcium handling, among other features. The lack of maturation that is observed in these cardiomyocytes greatly limits their applicability towards drug screening, disease modeling, and cell therapy applications. The mechanical environment surrounding a cell has been repeatedly shown to have a large impact on that cell's behavior. For this reason, we have implemented micropatterning methods to mimic the level of alignment that occurs in the heart in vivo in order to study how this alignment may help the cells to produce a more mature sarcomere phenotype. It was discovered that the level of sarcomere organization of a cardiomyocyte can be strongly influenced by the micropattern lane geometry on which it adheres. Steps were taken to optimize this micropattern platform, and studies of protein organization, gene expression, and myofibrillogenesis were conducted. Additionally, a set of programs was developed to provide quantitative analysis of the level of sarcomere organization, as well as to assist with several other tissue engineering applications.

  7. 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 ...

  8. Engineered metal nanoparticles in the sub-nanomolar levels kill cancer cells

    Directory of Open Access Journals (Sweden)

    Vodyanoy V

    2016-04-01

    Full Text Available Vitaly Vodyanoy,1 Yasmine Daniels,2 Oleg Pustovyy,1 William A MacCrehan,2 Shin Muramoto,2 Gheorghe Stan21Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL, 2Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MA, USA Background: Small metal nanoparticles obtained from animal blood were observed to be toxic to cultured cancer cells, whereas noncancerous cells were much less affected. In this work, engineered zinc and copper metal nanoparticles were produced from bulk metal rods by an underwater high-voltage discharge method. The metal nanoparticles were characterized by atomic force microscopy and X-ray photoelectron spectroscopy. The metal nanoparticles, with estimated diameters of 1 nm–2 nm, were determined to be more than 85% nonoxidized. A cell viability assay and high-resolution light microscopy showed that exposure of RG2, cultured rat brain glioma cancer cells, to the zinc and copper nanoparticles resulted in cell morphological changes, including decreased cell adherence, shrinking/rounding, nuclear condensation, and budding from cell bodies. The metal-induced cell injuries were similar to the effects of staurosporine, an active apoptotic reagent. The viability experiments conducted for zinc and copper yielded values of dissociation constants of 0.22±0.08 nmol/L (standard error [SE] and 0.12±0.02 nmol/L (SE, respectively. The noncancerous astrocytes were not affected at the same conditions. Because metal nanoparticles were lethal to the cancer cells at sub-nanomolar concentrations, they are potentially important as nanomedicine.Purpose: Lethal concentrations of synthetic metal nanoparticles reported in the literature are a few orders of magnitude higher than the natural, blood-isolated metal nanoparticles; therefore, in this work, engineered metal nanoparticles were examined to mimic the properties of endogenous metal

  9. Stem cell-derived vasculature: A potent and multidimensional technology for basic research, disease modeling, and tissue engineering.

    Science.gov (United States)

    Lowenthal, Justin; Gerecht, Sharon

    2016-05-01

    Proper blood vessel networks are necessary for constructing and re-constructing tissues, promoting wound healing, and delivering metabolic necessities throughout the body. Conversely, an understanding of vascular dysfunction has provided insight into the pathogenesis and progression of diseases both common and rare. Recent advances in stem cell-based regenerative medicine - including advances in stem cell technologies and related progress in bioscaffold design and complex tissue engineering - have allowed rapid advances in the field of vascular biology, leading in turn to more advanced modeling of vascular pathophysiology and improved engineering of vascularized tissue constructs. In this review we examine recent advances in the field of stem cell-derived vasculature, providing an overview of stem cell technologies as a source for vascular cell types and then focusing on their use in three primary areas: studies of vascular development and angiogenesis, improved disease modeling, and the engineering of vascularized constructs for tissue-level modeling and cell-based therapies.

  10. Development of large engineered cartilage constructs from a small population of cells.

    Science.gov (United States)

    Brenner, Jillian M; Kunz, Manuela; Tse, Man Yat; Winterborn, Andrew; Bardana, Davide D; Pang, Stephen C; Waldman, Stephen D

    2013-01-01

    Confronted with articular cartilage's limited capacity for self-repair, joint resurfacing techniques offer an attractive treatment for damaged or diseased tissue. Although tissue engineered cartilage constructs can be created, a substantial number of cells are required to generate sufficient quantities of tissue for the repair of large defects. As routine cell expansion methods tend to elicit negative effects on chondrocyte function, we have developed an approach to generate phenotypically stable, large-sized engineered constructs (≥3 cm(2) ) directly from a small amount of donor tissue or cells (as little as 20,000 cells to generate a 3 cm(2) tissue construct). Using rabbit donor tissue, the bioreactor-cultivated constructs were hyaline-like in appearance and possessed a biochemical composition similar to native articular cartilage. Longer bioreactor cultivation times resulted in increased matrix deposition and improved mechanical properties determined over a 4 week period. Additionally, as the anatomy of the joint will need to be taken in account to effectively resurface large affected areas, we have also explored the possibility of generating constructs matched to the shape and surface geometry of a defect site through the use of rapid-prototyped defect tissue culture molds. Similar hyaline-like tissue constructs were developed that also possessed a high degree of shape correlation to the original defect mold. Future studies will be aimed at determining the effectiveness of this approach to the repair of cartilage defects in an animal model and the creation of large-sized osteochondral constructs. PMID:23197468

  11. Biocompatible Azide-Alkyne "Click" Reactions for Surface Decoration of Glyco-Engineered Cells.

    Science.gov (United States)

    Gutmann, Marcus; Memmel, Elisabeth; Braun, Alexandra C; Seibel, Jürgen; Meinel, Lorenz; Lühmann, Tessa

    2016-05-01

    Bio-orthogonal copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been widely used to modify azide- or alkyne-bearing monosaccharides on metabolic glyco-engineered mammalian cells. Here, we present a systematic study to elucidate the design space for the cytotoxic effects of the copper catalyst on NIH 3T3 fibroblasts and on HEK 293-F cells. Monitoring membrane integrity by flow cytometry and RT-PCR analysis with apoptotic and anti-apoptotic markers elucidated the general feasibility of CuAAC, with exposure time of the CuAAC reaction mixture having the major influence on biocompatibility. A high labeling efficiency of HEK 293-F cells with a fluorescent alkyne dye was rapidly achieved by CuAAC in comparison to copper free strain-promoted azide-alkyne cycloaddition (SPAAC). The study details effective and biocompatible conditions for CuAAC-based modification of glyco-engineered cells in comparison to its copper free alternative. PMID:26818821

  12. Toward a bioengineered heparin: challenges and strategies for metabolic engineering of mammalian cells.

    Science.gov (United States)

    Baik, Jong Youn; Wang, Clifford L; Yang, Bo; Linhardt, Robert J; Sharfstein, Susan

    2012-01-01

    Heparin is the most widely used pharmaceutical to control blood coagulation in modern medicine. A health crisis that took place in 2008 led to a demand for production of heparin from non-animal sources. Since Chinese hamster ovary (CHO) cells are capable of producing heparan sulfate (HS), a related polysaccharide naturally, and heparin and HS share the same biosynthetic pathway, we hypothesized that heparin could be produced in CHO cells by metabolic engineering. We developed stable human N-deacetylase/N-sulfotransferase (NDST2) and mouse heparan sulfate 3-O-sulfotransferase 1 (Hs3st1) expressing cell lines based on the expression of endogenous enzymes in the HS/heparin pathways of CHO-S cells. Both activity assay and disaccharide analysis showed that engineered HS attained heparin-like characteristics but not identical to pharmaceutical heparin, suggesting that further balancing the expression of transgenes with the expression levels of endogenous enzymes involved in HS/heparin biosynthesis might be necessary. PMID:22714556

  13. Suicide Gene-Engineered Stromal Cells Reveal a Dynamic Regulation of Cancer Metastasis

    Science.gov (United States)

    Shen, Keyue; Luk, Samantha; Elman, Jessica; Murray, Ryan; Mukundan, Shilpaa; Parekkadan, Biju

    2016-02-01

    Cancer-associated fibroblasts (CAFs) are a major cancer-promoting component in the tumor microenvironment (TME). The dynamic role of human CAFs in cancer progression has been ill-defined because human CAFs lack a unique marker needed for a cell-specific, promoter-driven knockout model. Here, we developed an engineered human CAF cell line with an inducible suicide gene to enable selective in vivo elimination of human CAFs at different stages of xenograft tumor development, effectively circumventing the challenge of targeting a cell-specific marker. Suicide-engineered CAFs were highly sensitive to apoptosis induction in vitro and in vivo by the addition of a simple small molecule inducer. Selection of timepoints for targeted CAF apoptosis in vivo during the progression of a human breast cancer xenograft model was guided by a bi-phasic host cytokine response that peaked at early timepoints after tumor implantation. Remarkably, we observed that the selective apoptosis of CAFs at these early timepoints did not affect primary tumor growth, but instead increased the presence of tumor-associated macrophages and the metastatic spread of breast cancer cells to the lung and bone. The study revealed a dynamic relationship between CAFs and cancer metastasis that has counter-intuitive ramifications for CAF-targeted therapy.

  14. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells.

    Science.gov (United States)

    Goldman, Stephen M; Barabino, Gilda A

    2016-01-01

    The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products. PMID:27190700

  15. A validated system for ligation-free USER™ -based assembly of expression vectors for mammalian cell engineering

    DEFF Research Database (Denmark)

    Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Hansen, Bjarne Gram;

    The development in the field of mammalian cell factories require fast and high-throughput methods, this means a high need for simpler and more efficient cloning techniques. For optimization of protein expression by genetic engineering and for allowing metabolic engineering in mammalian cells, a new...... versatile expression vector system was developed. This vector system applies the ligation-free uracilexcision cloning technique to construct mammalian expression vectors of multiple parts and with maximum flexibility....

  16. Continuous release of interleukin 12 from microencapsulated engineered cells for colon cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Shu Zheng; Zuo-Xiang Xiao; Yue-Long Pan; Ming-Yong Han; Qi Dong

    2003-01-01

    AIM: To explore the anti-tumor immunity against CT26 colon tumor of the microencapsulated cells modified with murine interleukine-12 (mIL-12) gene.METHODS: Mouse fibroblasts (NIH3T3) were stably transfected to express mIL-12 using expression plasmids carrying mIL-12 gene (p35 and p40), and NIH3T3-mIL-12cells were encapsulated in alginate microcapsules for longterm delivery of mIL-12. mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells was confirmed using ELISA assay. Transplantation of the microencapsulated NIH3T3-mIL-12 cells was performed in the tumor-bearing mice with CT26 cells. The anti-tumor responses and the anti-tumor activities of the microencapsulated NIH3T3-mIL12 cells were evaluated.RESULTS: Microencapsulated NIH3T3-mIL-12 cells could release mIL-12 continuously and stably for a long time. After the microencapsulated NIH3T3-mIL-12 cells were transplanted subcutaneously into the tumor-bearing mice for 21 d, the serum concentrations of mIL-12, mIL-2 and mIFN-γ the cytotoxicity of the CTL from the splenocytes and the NK activity in the treatment group were significantly higher than those in the controls. Moreover, mIL-12 released from the microencapsulated NIH3T3-mIL-12 cells resulted in a significant inhibition of tumor proliferation and a prolonged survival of tumor-bearing mice.CONCLUSION: The microencapsulated NIH3T3-mIL-12cells have a significant therapeutic effect on the experimental colon tumor by activating anti-tumor immune responses in vivo. Microencapsulated and genetically engineered cells may be an extremely versatile tool for tumor gene therapy.

  17. Recent advances in T-cell engineering for use in immunotherapy [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Preeti Sharma

    2016-09-01

    Full Text Available Adoptive T-cell therapies have shown exceptional promise in the treatment of cancer, especially B-cell malignancies. Two distinct strategies have been used to redirect the activity of ex vivo engineered T cells. In one case, the well-known ability of the T-cell receptor (TCR to recognize a specific peptide bound to a major histocompatibility complex molecule has been exploited by introducing a TCR against a cancer-associated peptide/human leukocyte antigen complex. In the other strategy, synthetic constructs called chimeric antigen receptors (CARs that contain antibody variable domains (single-chain fragments variable and signaling domains have been introduced into T cells. Whereas many reviews have described these two approaches, this review focuses on a few recent advances of significant interest. The early success of CARs has been followed by questions about optimal configurations of these synthetic constructs, especially for efficacy against solid tumors. Among the many features that are important, the dimensions and stoichiometries of CAR/antigen complexes at the synapse have recently begun to be appreciated. In TCR-mediated approaches, recent evidence that mutated peptides (neoantigens serve as targets for endogenous T-cell responses suggests that these neoantigens may also provide new opportunities for adoptive T-cell therapies with TCRs.

  18. Differentiation of mesenchymal stem cells into neuronal cells on fetal bovine acellular dermal matrix as a tissue engineered nerve scaffold

    Institute of Scientific and Technical Information of China (English)

    Yuping Feng; Jiao Wang; Shixin Ling; Zhuo Li; Mingsheng Li; Qiongyi Li; Zongren Ma; Sijiu Yu

    2014-01-01

    The purpose of this study was to assess fetal bovine acellular dermal matrix as a scaffold for supporting the differentiation of bone marrow mesenchymal stem cells into neural cells fol-lowing induction with neural differentiation medium. We performed long-term, continuous observation of cell morphology, growth, differentiation, and neuronal development using several microscopy techniques in conjunction with immunohistochemistry. We examined speciifc neu-ronal proteins and Nissl bodies involved in the differentiation process in order to determine the neuronal differentiation of bone marrow mesenchymal stem cells. The results show that bone marrow mesenchymal stem cells that differentiate on fetal bovine acellular dermal matrix display neuronal morphology with unipolar and bi/multipolar neurite elongations that express neuro-nal-speciifc proteins, includingβIII tubulin. The bone marrow mesenchymal stem cells grown on fetal bovine acellular dermal matrix and induced for long periods of time with neural differen-tiation medium differentiated into a multilayered neural network-like structure with long nerve ifbers that was composed of several parallel microifbers and neuronal cells, forming a complete neural circuit with dendrite-dendrite to axon-dendrite to dendrite-axon synapses. In addition, growth cones with filopodia were observed using scanning electron microscopy. Paraffin sec-tioning showed differentiated bone marrow mesenchymal stem cells with the typical features of neuronal phenotype, such as a large, round nucleus and a cytoplasm full of Nissl bodies. The data suggest that the biological scaffold fetal bovine acellular dermal matrix is capable of supporting human bone marrow mesenchymal stem cell differentiation into functional neurons and the subsequent formation of tissue engineered nerve.

  19. Accelerating the Execution of Matrix Languages on the Cell Broadband Engine Architecture

    CERN Document Server

    Khoury, Raymes; Scholz, Bernhard

    2009-01-01

    Matrix languages, including MATLAB and Octave, are established standards for applications in science and engineering. They provide interactive programming environments that are easy to use due to their script languages with matrix data types. Current implementations of matrix languages do not fully utilize high-performance, special-purpose chip architectures such as the IBM PowerXCell processor (Cell), which is currently used in the fastest computer in the world. We present a new framework that extends Octave to harvest the computational power of the Cell. With this framework the programmer is alleviated of the burden of introducing explicit notions of parallelism. Instead the programmer uses a new matrix data-type to execute matrix operations in parallel on the synergistic processing elements (SPEs) of the Cell. We employ lazy evaluation semantics for our new matrix data-type to obtain execution traces of matrix operations. Traces are converted to data dependence graphs; operations in the data dependence gra...

  20. Towards Engineered Processes for Sequencing-Based Analysis of Single Circulating Tumor Cells.

    Science.gov (United States)

    Adalsteinsson, Viktor A; Love, J Christopher

    2014-05-01

    Sequencing-based analysis of single circulating tumor cells (CTCs) has the potential to revolutionize our understanding of metastatic cancer and improve clinical care. Technologies exist to enrich, identify, recover, and sequence single cells, but to enable systematic routine analysis of single CTCs from a range of cancer patients, there is a need to establish processes that efficiently integrate these specific operations. Such engineered processes should address challenges associated with the yield and viability of enriched CTCs, the robust identification of candidate single CTCs with minimal degradation of DNA, the bias in whole-genome amplification, and the efficient handling of candidate single CTCs or their amplified DNA products. Advances in methods for single-cell analysis and nanoscale technologies suggest opportunities to overcome these challenges, and could create integrated platforms that perform several of the unit operations together. Ultimately, technologies should be selected or adapted for optimal performance and compatibility in an integrated process. PMID:24839591

  1. Investigation the Porous Collagen-Chitosan /Glycosaminoglycans for Corneal Cell Culture as Tissue Engineering Scaffold

    Institute of Scientific and Technical Information of China (English)

    LI Qin-Hua; CHEN Jian-Su

    2005-01-01

    The objective of this study was to produce the porous collagen-chitosan/Glycosanminglycans (GAG) for corneal ceil-seed implant as a three-dimensional tissue engineering scaffold to improve the regeneration corneas. The effect of various content of glycerol as form porous agent to collagen-chitosan/GAG preserved a porous dimensional structure was investigated. The heat-drying was used to prepare porous collagen-chitosan /GAG scaffold. The pore morphology of collagenchitosan/GAG was controlled by changing the concentration of glycerol solution and drying methods. The porous structure morphology was observed by SEM. The diameter of the pores form 10 to 50 μm. The highly porous scaffold had interconnecting pores. The corneal cell morphology was observed under the light microscope. These results suggest that collagen-chitosan/GAG showed that corneal cell have formed confluent layers and resemble the surface of normal corneal cell surface.

  2. Physiological, pathological, and engineered cell identity reprogramming in the central nervous system.

    Science.gov (United States)

    Smith, Derek K; Wang, Lei-Lei; Zhang, Chun-Li

    2016-07-01

    Multipotent neural stem cells persist in restricted regions of the adult mammalian central nervous system. These proliferative cells differentiate into diverse neuron subtypes to maintain neural homeostasis. This endogenous process can be reprogrammed as a compensatory response to physiological cues, traumatic injury, and neurodegeneration. In addition to innate neurogenesis, recent research has demonstrated that new neurons can be engineered via cell identity reprogramming in non-neurogenic regions of the adult central nervous system. A comprehensive understanding of these reprogramming mechanisms will be essential to the development of therapeutic neural regeneration strategies that aim to improve functional recovery after injury and neurodegeneration. WIREs Dev Biol 2016, 5:499-517. doi: 10.1002/wdev.234 For further resources related to this article, please visit the WIREs website. PMID:27258392

  3. The early career researcher's toolkit: translating tissue engineering, regenerative medicine and cell therapy products.

    Science.gov (United States)

    Rafiq, Qasim A; Ortega, Ilida; Jenkins, Stuart I; Wilson, Samantha L; Patel, Asha K; Barnes, Amanda L; Adams, Christopher F; Delcassian, Derfogail; Smith, David

    2015-11-01

    Although the importance of translation for the development of tissue engineering, regenerative medicine and cell-based therapies is widely recognized, the process of translation is less well understood. This is particularly the case among some early career researchers who may not appreciate the intricacies of translational research or make decisions early in development which later hinders effective translation. Based on our own research and experiences as early career researchers involved in tissue engineering and regenerative medicine translation, we discuss common pitfalls associated with translational research, providing practical solutions and important considerations which will aid process and product development. Suggestions range from effective project management, consideration of key manufacturing, clinical and regulatory matters and means of exploiting research for successful commercialization. PMID:26628407

  4. 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

  5. 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

  6. Integrated cell and process engineering for improved transient production of a "difficult-to-express" fusion protein by CHO cells.

    Science.gov (United States)

    Johari, Yusuf B; Estes, Scott D; Alves, Christina S; Sinacore, Marty S; James, David C

    2015-12-01

    Based on an optimized electroporation protocol, we designed a rapid, milliliter-scale diagnostic transient production assay to identify limitations in the ability of Chinese hamster ovary (CHO) cells to produce a model "difficult-to-express" homodimeric Fc-fusion protein, Sp35Fc, that exhibited very low volumetric titer and intracellular formation of disulfide-bonded oligomeric aggregates post-transfection. As expression of Sp35Fc induced an unfolded protein response in transfected host cells, we utilized the transient assay to compare, in parallel, multiple functionally diverse strategies to engineer intracellular processing of Sp35Fc in order to increase production and reduce aggregation as two discrete design objectives. Specifically, we compared the effect of (i) co-expression of ER-resident molecular chaperones (BiP, PDI, CypB) or active forms of UPR transactivators (ATF6c, XBP1s) at varying recombinant gene load, (ii) addition of small molecules known to act as chemical chaperones (PBA, DMSO, glycerol, betaine, TMAO) or modulate UPR signaling (PERK inhibitor GSK2606414) at varying concentration, (iii) a reduction in culture temperature to 32°C. Using this information, we designed a biphasic, Sp35Fc-specific transient manufacturing process mediated by lipofection that utilized CypB co-expression at an optimal Sp35Fc:CypB gene ratio of 5:1 to initially maximize transfected cell proliferation, followed by addition of a combination of PBA (0.5 mM) and glycerol (1% v/v) at the onset of stationary phase to maximize cell specific production and eliminate Sp35Fc aggregation. Using this optimal, engineered process transient Sp35Fc production was significantly increased sixfold over a 12 day production process with no evidence of disulfide-bonded aggregates. Finally, transient production in clonally derived sub-populations (derived from parental CHO host) screened for a heritably improved capability to produce Sp35Fc was also significantly improved by the optimized

  7. Metabolic engineering of Chinese hamster ovary cells: towards a bioengineered heparin.

    Science.gov (United States)

    Baik, Jong Youn; Gasimli, Leyla; Yang, Bo; Datta, Payel; Zhang, Fuming; Glass, Charles A; Esko, Jeffrey D; Linhardt, Robert J; Sharfstein, Susan T

    2012-03-01

    Heparin is the most widely used pharmaceutical to control blood coagulation in modern medicine. A health crisis that took place in 2008 led to a demand for production of heparin from non-animal sources. Chinese hamster ovary (CHO) cells, commonly used mammalian host cells for production of foreign pharmaceutical proteins in the biopharmaceutical industry, are capable of producing heparan sulfate (HS), a related polysaccharide naturally. Since heparin and HS share the same biosynthetic pathway, we hypothesized that heparin could be produced in CHO cells by metabolic engineering. Based on the expression of endogenous enzymes in the HS/heparin pathways of CHO-S cells, human N-deacetylase/N-sulfotransferase (NDST2) and mouse heparan sulfate 3-O-sulfotransferase 1 (Hs3st1) genes were transfected sequentially into CHO host cells growing in suspension culture. Transfectants were screened using quantitative RT-PCR and Western blotting. Out of 120 clones expressing NDST2 and Hs3st1, 2 clones, Dual-3 and Dual-29, were selected for further analysis. An antithrombin III (ATIII) binding assay using flow cytometry, designed to recognize a key sugar structure characteristic of heparin, indicated that Hs3st1 transfection was capable of increasing ATIII binding. An anti-factor Xa assay, which affords a measure of anticoagulant activity, showed a significant increase in activity in the dual-expressing cell lines. Disaccharide analysis of the engineered HS showed a substantial increase in N-sulfo groups, but did not show a pattern consistent with pharmacological heparin, suggesting that further balancing the expression of transgenes with the expression levels of endogenous enzymes involved in HS/heparin biosynthesis might be necessary. PMID:22326251

  8. Decolorization of industrial synthetic dyes using engineered Pseudomonas putida cells with surface-immobilized bacterial laccase

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2012-06-01

    Full Text Available Abstract Background Microbial laccases are highly useful in textile effluent dye biodegradation. However, the bioavailability of cellularly expressed or purified laccases in continuous operations is usually limited by mass transfer impediment or enzyme regeneration difficulty. Therefore, this study develops a regenerable bacterial surface-displaying system for industrial synthetic dye decolorization, and evaluates its effects on independent and continuous operations. Results A bacterial laccase (WlacD was engineered onto the cell surface of the solvent-tolerant bacterium Pseudomonas putida to construct a whole-cell biocatalyst. Ice nucleation protein (InaQ anchor was employed, and the ability of 1 to 3 tandemly aligned N-terminal repeats to direct WlacD display were compared. Immobilized WlacD was determined to be surface-displayed in functional form using Western blot analysis, immunofluorescence microscopy, flow cytometry, and whole-cell enzymatic activity assay. Engineered P. putida cells were then applied to decolorize the anthraquinone dye Acid Green (AG 25 and diazo-dye Acid Red (AR 18. The results showed that decolorization of both dyes is Cu2+- and mediator-independent, with an optimum temperature of 35°C and pH of 3.0, and can be stably performed across a temperature range of 15°C to 45°C. A high activity toward AG25 (1 g/l with relative decolorization values of 91.2% (3 h and 97.1% (18 h, as well as high activity to AR18 (1 g/l by 80.5% (3 h and 89.0% (18 h, was recorded. The engineered system exhibited a comparably high activity compared with those of separate dyes in a continuous three-round shake-flask decolorization of AG25/AR18 mixed dye (each 1 g/l. No significant decline in decolorization efficacy was noted during first two-rounds but reaction equilibriums were elongated, and the residual laccase activity eventually decreased to low levels. However, the decolorizing capacity of the system was easily retrieved

  9. Effects of Dexamethasone on Satellite Cells and Tissue Engineered Skeletal Muscle Units.

    Science.gov (United States)

    Syverud, Brian C; VanDusen, Keith W; Larkin, Lisa M

    2016-03-01

    Tissue engineered skeletal muscle has potential for application as a graft source for repairing soft tissue injuries, a model for testing pharmaceuticals, and a biomechanical actuator system for soft robots. However, engineered muscle to date has not produced forces comparable to native muscle, limiting its potential for repair and for use as an in vitro model for pharmaceutical testing. In this study, we examined the trophic effects of dexamethasone (DEX), a glucocorticoid that stimulates myoblast differentiation and fusion into myotubes, on our tissue engineered three-dimensional skeletal muscle units (SMUs). Using our established SMU fabrication protocol, muscle isolates were cultured with three experimental DEX concentrations (5, 10, and 25 nM) and compared to untreated controls. Following seeding onto a laminin-coated Sylgard substrate, the administration of DEX was initiated on day 0 or day 6 in growth medium or on day 9 after the switch to differentiation medium and was sustained until the completion of SMU fabrication. During this process, total cell proliferation was measured with a BrdU assay, and myogenesis and structural advancement of muscle cells were observed through immunostaining for MyoD, myogenin, desmin, and α-actinin. After SMU formation, isometric tetanic force production was measured to quantify function. The histological and functional assessment of the SMU showed that the administration of 10 nM DEX beginning on either day 0 or day 6 yielded optimal SMUs. These optimized SMUs exhibited formation of advanced sarcomeric structure and significant increases in myotube diameter and myotube fusion index, compared with untreated controls. Additionally, the optimized SMUs matured functionally, as indicated by a fivefold rise in force production. In conclusion, we have demonstrated that the addition of DEX to our process of engineering skeletal muscle tissue improves myogenesis, advances muscle structure, and increases force production in the

  10. Brain microvascular endothelial cell association and distribution of a 5 nm ceria engineered nanomaterial

    Directory of Open Access Journals (Sweden)

    Dan M

    2012-07-01

    Full Text Available Mo Dan,1,2 Michael T Tseng,3 Peng Wu,4 Jason M Unrine,5 Eric A Grulke,4 Robert A Yokel1,21Department of Pharmaceutical Sciences, College of Pharmacy, 2Graduate Center for Toxicology, University of Kentucky, Lexington, KY, USA; 3Departments of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, USA; 4Chemical and Materials Engineering Department, 5Department of Plant and Soil Science, University of Kentucky, Lexington, KY, USAPurpose: Ceria engineered nanomaterials (ENMs have current commercial applications and both neuroprotective and toxic effects. Our hypothesis is that ceria ENMs can associate with brain capillary cells and/or cross the blood–brain barrier.Methods: An aqueous dispersion of ~5 nm ceria ENM was synthesized and characterized in house. Its uptake space in the Sprague Dawley rat brain was determined using the in situ brain perfusion technique at 15 and 20 mL/minute flow rates; 30, 100, and 500 µg/mL ceria perfused for 120 seconds at 20 mL/minute; and 30 µg/mL perfused for 20, 60, and 120 seconds at 20 mL/minute. The capillary depletion method and light and electron microscopy were used to determine its capillary cell and brain parenchymal association and localization.Results: The vascular space was not significantly affected by brain perfusion flow rate or ENM, demonstrating that this ceria ENM did not influence blood–brain barrier integrity. Cerium concentrations, determined by inductively coupled plasma mass spectrometry, were significantly higher in the choroid plexus than in eight brain regions in the 100 and 500 µg/mL ceria perfusion groups. Ceria uptake into the eight brain regions was similar after 120-second perfusion of 30, 100, and 500 µg ceria/mL. Ceria uptake space significantly increased in the eight brain regions and choroid plexus after 60 versus 20 seconds, and it was similar after 60 and 120 seconds. The capillary depletion method showed 99.4% ± 1.1% of the ceria ENM associated

  11. In situ nanomechanics of cell-biomaterial composites for tissue engineering applications

    Science.gov (United States)

    Khanna, Rohit

    For the first time, we report an experimental design, development and evaluation of in situ nanomechanics of cell-biomaterial composites for tissue engineering applications. A blend of two biopolymers (Chitosan and Polygalacturonic acid) was chosen with hydroxyapatite nanoparticles to mimic the natural bone (Chi-PgA-HAP). These substrates swell in presence of cell culture media as found by our in situ topographical, chemical and mechanical analyses for 48 days. Biocompatibility experiments were performed using human osteoblasts (CRL 11732) and results indicate that these substrates favor cell adhesion and proliferation. Over cell culture duration of 22 days, osteoblasts generated bone-like nodules onto Chi-PgA-HAP substrates in absence of any stimulants for osteogenesis. In vitro generated bone nodule mimics the structure, chemistry and nanomechanical properties of natural bone as revealed by Atomic Force Microscopy (AFM), and Fourier Transform Infrared (FTIR) analyses on bone nodule. Hierarchically organized extracellular matrix of bone nodule consisting of mineralized collagen fibers, fibrils and mineral deposits was revealed by high resolution AFM images. FTIR analyses on bone nodule suggests that bone nodule is chemically similar to human bone due to the presence of major bands of collagen (Amide I, II, and III) and biological apatite (CO32- and HPO 43). Live cell and cell-substrate nanoindentation experiments on cell seeded Chi-PgA-HAP nanocomposites were conducted under the physiological conditions (cell culture Name: Rohit Khanna medium; 37°C) for culture duration of 1, 4, 8, and 22 days, respectively. Dynamic mechanical responses of cells are indicated by stiffer elastic responses of flat cells as compared to round cells. Dynamic mechanical behavior of cell-degrading substrate is indicated by their corresponding elastic moduli: ECell-Chi-PgA-HAP, 1 day, 2000 nm= 10.3-20.2 MPa, ECell-Chi-PgA-HAP, 4 days, 2000 nm = 5.2-8.4 MPa and ECell-Chi-PgA-HAP. 8 days

  12. Sensor Needs and Requirements for Fuel Cells and CIDI/SIDI Engines

    Energy Technology Data Exchange (ETDEWEB)

    Glass, R.S.

    2000-03-01

    To reduce U.S. dependence on imported oil, improve urban air quality, and decrease greenhouse gas emissions, the Department of Energy (DOE) is developing advanced vehicle technologies and fuels. Enabling technologies for fuel cell power systems and direct-injection engines are being developed by DOE through the Partnership for a New Generation of Vehicles (PNGV), a government-industry collaboration to produce vehicles having up to three times the fuel economy of conventional mid-size automobiles. Sensors have been identified as a research and development need for both fuel cell and direct-injection systems, because current sensor technologies do not adequately meet requirements. Sensors are needed for emission control, for passenger safety and comfort, to increase system lifetime, and for system performance enhancement through feedback and control. These proceedings document the results of a workshop to define sensor requirements for proton exchange membrane (PEM) fuel cell systems and direct-injection engines for automotive applications. The recommendations from this workshop will be incorporated into the multi-year R&D plan of the DOE Office of Advanced Automotive Technologies. The objectives of the workshop were to: define the requirements for sensors; establish R&D priorities; identify the technical targets and technical barriers; and facilitate collaborations among participants. The recommendations from this workshop will be incorporated into the multi-year R&D plan of the DOE Office of Advanced Automotive Technologies.

  13. [Vascular prostheses: 50 years of advancement from synthetic towards tissue engineering and cell therapy].

    Science.gov (United States)

    Chlupác, J; Filová, E; Bacáková, L

    2010-01-01

    Since more than 50 years, the gold standard in synthetic vascular prostheses has been represented by polyethylene terephtalate (PET, Dacron) and expanded polytetrafluoroethylene (ePTFE). These polymers perform well as sustitutes of large-caliber vessels, however, their long-term patencies are disappointing in small-caliber applications (< 6 mm). Thus, patient's own artery or vein remains the material of choice in coronary, crural or microvessel bypass surgery. Synthetic materials fail due to thrombosis and insufficient healing process that consists in highly incomplete endothelial cells coverage and intimal hyperplasia caused by compliance mismatch and hemodynamic imbalance. To find better small-caliber vascular graft, surgical techniques have been modified, novel biomaterials have been investigated and cell and tissue culture technologies have been adopted. Partly or fully tissue-engineered vascular grafts have been produced and experimentally and clinically evaluated with some promising result. The aim of this review is to briefly list currently used and examined vascular graft materials with special attention to cell/biomaterial ineractions, tissue engineering and authors' own experience. PMID:21351411

  14. Cell-mediated retraction versus hemodynamic loading - A delicate balance in tissue-engineered heart valves.

    Science.gov (United States)

    van Loosdregt, Inge A E W; Argento, Giulia; Driessen-Mol, Anita; Oomens, Cees W J; Baaijens, Frank P T

    2014-06-27

    Preclinical studies of tissue-engineered heart valves (TEHVs) showed retraction of the heart valve leaflets as major failure of function mechanism. This retraction is caused by both passive and active cell stress and passive matrix stress. Cell-mediated retraction induces leaflet shortening that may be counteracted by the hemodynamic loading of the leaflets during diastole. To get insight into this stress balance, the amount and duration of stress generation in engineered heart valve tissue and the stress imposed by physiological hemodynamic loading are quantified via an experimental and a computational approach, respectively. Stress generation by cells was measured using an earlier described in vitro model system, mimicking the culture process of TEHVs. The stress imposed by the blood pressure during diastole on a valve leaflet was determined using finite element modeling. Results show that for both pulmonary and systemic pressure, the stress imposed on the TEHV leaflets is comparable to the stress generated in the leaflets. As the stresses are of similar magnitude, it is likely that the imposed stress cannot counteract the generated stress, in particular when taking into account that hemodynamic loading is only imposed during diastole. This study provides a rational explanation for the retraction found in preclinical studies of TEHVs and represents an important step towards understanding the retraction process seen in TEHVs by a combined experimental and computational approach. PMID:24268314

  15. Extracellular matrix of dental pulp stem cells: Applications in pulp tissue engineering using somatic MSCs

    Directory of Open Access Journals (Sweden)

    Sriram eRavindran

    2014-01-01

    Full Text Available Dental Caries affects approximately 90% of the world’s population. At present, the clinical treatment for dental caries is root canal therapy. This treatment results in loss of tooth sensitivity and vitality. Tissue engineering can potentially solve this problem by enabling regeneration of a functional pulp tissue. Dental pulp stem cells (DPSCs have been shown to be an excellent source for pulp regeneration. However, limited availability of these cells hinders its potential for clinical translation. We have investigated the possibility of using somatic mesenchymal stem cells from other sources for dental pulp tissue regeneration using a biomimetic dental pulp extracellular matrix (ECM incorporated scaffold. Human periodontal ligament stem cells (PDLSCs and human bone marrow stromal cells (HMSCs were investigated for their ability to differentiate towards an odontogenic lineage. In vitro real-time PCR results coupled with histological and immunohistochemical examination of the explanted tissues confirmed the ability of PDLSCs and HMSCs to form a vascularized pulp-like tissue. These findings indicate that the dental pulp stem derived ECM scaffold stimulated odontogenic differentiation of PDLSCs and HMSCs without the need for exogenous addition of growth and differentiation factors. This study represents a translational perspective toward possible therapeutic application of using a combination of somatic stem cells and extracellular matrix for pulp regeneration.

  16. Streaming Model Based Volume Ray Casting Implementation for Cell Broadband Engine

    Directory of Open Access Journals (Sweden)

    Jusub Kim

    2009-01-01

    Full Text Available Interactive high quality volume rendering is becoming increasingly more important as the amount of more complex volumetric data steadily grows. While a number of volumetric rendering techniques have been widely used, ray casting has been recognized as an effective approach for generating high quality visualization. However, for most users, the use of ray casting has been limited to datasets that are very small because of its high demands on computational power and memory bandwidth. However the recent introduction of the Cell Broadband Engine (Cell B.E. processor, which consists of 9 heterogeneous cores designed to handle extremely demanding computations with large streams of data, provides an opportunity to put the ray casting into practical use. In this paper, we introduce an efficient parallel implementation of volume ray casting on the Cell B.E. The implementation is designed to take full advantage of the computational power and memory bandwidth of the Cell B.E. using an intricate orchestration of the ray casting computation on the available heterogeneous resources. Specifically, we introduce streaming model based schemes and techniques to efficiently implement acceleration techniques for ray casting on Cell B.E. In addition to ensuring effective SIMD utilization, our method provides two key benefits: there is no cost for empty space skipping and there is no memory bottleneck on moving volumetric data for processing. Our experimental results show that we can interactively render practical datasets on a single Cell B.E. processor.

  17. Multilineage co-culture of adipose-derived stem cells for tissue engineering.

    Science.gov (United States)

    Zhao, Yimu; Waldman, Stephen D; Flynn, Lauren E

    2015-07-01

    Stem cell interactions through paracrine cell signalling can regulate a range of cell responses, including metabolic activity, proliferation and differentiation. Moving towards the development of optimized tissue-engineering strategies with adipose-derived stem cells (ASCs), the focus of this study was on developing indirect co-culture models to study the effects of mature adipocytes, chondrocytes and osteoblasts on bovine ASC multilineage differentiation. For each lineage, ASC differentiation was characterized by histology, gene expression and protein expression, in the absence of key inductive differentiation factors for the ASCs. Co-culture with each of the mature cell populations was shown to successfully induce or enhance lineage-specific differentiation of the ASCs. In general, a more homogeneous but lower-level differentiation response was observed in co-culture as compared to stimulating the bovine ASCs with inductive differentiation media. To explore the role of the Wnt canonical and non-canonical signalling pathways within the model systems, the effects of the Wnt inhibitors WIF-1 and DKK-1 on multilineage differentiation in co-culture were assessed. The data indicated that Wnt signalling may play a role in mediating ASC differentiation in co-culture with the mature cell populations. PMID:23135884

  18. Armed and accurate: engineering cytotoxic T cells for eradication of leukemia

    Directory of Open Access Journals (Sweden)

    Radic Marko

    2012-02-01

    Full Text Available Abstract Translational medicine depends on a rapid and efficient exchange of results between the bench and the bedside. A recent example from the field of cancer immunotherapy highlights the essential nature of this exchange. Methods have been developed to convert a patient's cytotoxic T cells into efficient and specific killers of cancer cells in patients with leukemia. By using recombinant DNA techniques, a lentiviral vector was constructed to express chimeric antigen receptors in cytotoxic T cells from patients with advanced chronic lymphocytic leukemia. The purpose of the chimeric receptors was to direct the cytotoxic T cell activity against cells causing the cancer. The effect of infusing the engineered T cells back into the cancer patients was tested in a Phase I trial at the University of Pennsylvania, and the initial results were described in two articles from the research team of Dr. Carl June. The remarkable success of this trial should energize further applications of biotechnology in the development of new cancer immunotherapies.

  19. Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control

    Directory of Open Access Journals (Sweden)

    Torres-Costa V

    2012-02-01

    Full Text Available Vicente Torres-Costa1, Gonzalo Martínez-Muñoz2, Vanessa Sánchez-Vaquero3, Álvaro Muñoz-Noval1, Laura González-Méndez3, Esther Punzón-Quijorna1,4, Darío Gallach-Pérez1, Miguel Manso-Silván1, Aurelio Climent-Font1,4, Josefa P García-Ruiz3, Raúl J Martín-Palma11Department of Applied Physics, 2Department of Computer Science, 3Department of Molecular Biology, 4Centre for Micro Analysis of Materials, Universidad Autónoma de Madrid, Madrid, SpainAbstract: The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D and two-dimensional (2-D patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally.Keywords: surface patterns, silicon, hMSCs, ion-beam patterning

  20. Polarised light sheet tomography.

    Science.gov (United States)

    Reidt, Sascha L; O'Brien, Daniel J; Wood, Kenneth; MacDonald, Michael P

    2016-05-16

    The various benefits of light sheet microscopy have made it a widely used modality for capturing three-dimensional images. It is mostly used for fluorescence imaging, but recently another technique called light sheet tomography solely relying on scattering was presented. The method was successfully applied to imaging of plant roots in transparent soil, but is limited when it comes to more turbid samples. This study presents a polarised light sheet tomography system and its advantages when imaging in highly scattering turbid media. The experimental configuration is guided by Monte Carlo radiation transfer methods, which model the propagation of a polarised light sheet in the sample. Images of both reflecting and absorbing phantoms in a complex collagenous matrix were acquired, and the results for different polarisation configurations are compared. Focus scanning methods were then used to reduce noise and produce three-dimensional reconstructions of absorbing targets. PMID:27409945

  1. Global ice sheet modeling

    International Nuclear Information System (INIS)

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed

  2. 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,...

  3. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  4. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  5. 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.

  6. Tracking stem cells in tissue-engineered organs using magnetic nanoparticles

    Science.gov (United States)

    Hachani, Roxanne; Lowdell, Mark; Birchall, Martin; Thanh, NguyêN. Thi Kim

    2013-11-01

    The use of human stem cells (SCs) in tissue engineering holds promise in revolutionising the treatment of numerous diseases. There is a pressing need to comprehend the distribution, movement and role of SCs once implanted onto scaffolds. Nanotechnology has provided a platform to investigate this through the development of inorganic magnetic nanoparticles (MNPs). MNPs can be used to label and track SCs by magnetic resonance imaging (MRI) since this clinically available imaging modality has high spatial resolution. In this review, we highlight recent applications of iron oxide and gadolinium based MNPs in SC labelling and MRI; and offer novel considerations for their future development.

  7. 犬牙囊干细胞膜片的构建及生物学特性的研究%Construction of Dental Follicle Stem Cell Sheet and its Biological Characteristics in Beagle Dogs

    Institute of Scientific and Technical Information of China (English)

    黄闯; 宋镜明; 宋扬; 刘佳; 王丽颖; 金作林

    2012-01-01

    Objective: To study the construction of dental follicle stem cell sheet and its biological characteristics in Beagle dogs. Methods: After identification.DFSCs were sub-cultured to construct DFSCs sheet. Cell sheet was investaged by inverted microscope, HE staining and scanning electron microscope (SEM). DFSCs sheets were induced by adipogenesis inducing medium and osteogenic medium for 14 days separately. Oil red staining and Alizarin red staining was applied to examine adipogenic induction and osteogenic induction. Results: DFSCs showed typical spindle shape.. Colony-forming assay results showed about 5.1% DFSCs colony formation. DFSCs were positive for CD29 and CD44, but negative for CD34. MTT manifested the growth and proliferation was good. Cell cycle testing showed: G1=87.1%,G2=5.54%. DFSCs sheets were constructed successfully and its growth in multilayer. It found that DFSCs expanded adequately and extracellular matrix(ECM) was clear and numerous in scanning electron micrescopy.Oil red staining and alizarin red staining both demonstrated positive reactions in DFSCs sheet after induction. Conclusion: It suggested that DFSCs cell sheet may be constructed and has a strong bone-forming ability.%目的:利用犬牙囊干细胞(Dental Follicle Stem Cells,DFSCs)构建细胞膜片并研究其生物学特性.方法:取4至6月龄犬尖牙牙胚,分离培养DFSCs,鉴定.用含抗坏血酸的培养基诱导2周构建细胞膜片,并通过倒置显微镜、HE染色、茜素红染色、油红染色、扫描电镜(SEM)对膜片进行形态学检测,检测成骨、成脂能力.结果:DFSCs于体外被成功分离、纯化、培养,细胞克隆形成率约为5.1%.流式鉴定为CD29+CD44+CD34-,增殖能力及克隆形成能力较强,并能成功构建成细胞膜片.光镜和电镜显示膜片细胞排列紧密,细胞基质分泌多,油红O染色后可见细胞内有大量脂滴形成.(B)茜素红染色后可见大量清晰的钙结节形成.结论:成功构建犬DFSCs膜

  8. Fabrication of endothelial cell-laden carrageenan microfibers for microvascularized bone tissue engineering applications.

    Science.gov (United States)

    Mihaila, Silvia M; Popa, Elena G; Reis, Rui L; Marques, Alexandra P; Gomes, Manuela E

    2014-08-11

    Recent achievements in the area of tissue engineering (TE) have enabled the development of three-dimensional (3D) cell-laden hydrogels as in vitro platforms that closely mimic the 3D scenario found in native tissues. These platforms are extensively used to evaluate cellular behavior, cell-cell interactions, and tissue-like formation in highly defined settings. In this study, we propose a scalable and flexible 3D system based on microsized hydrogel fibers that might be used as building blocks for the establishment of 3D hydrogel constructs for vascularized bone TE applications. For this purpose, chitosan (CHT) coated κ-carrageenan (κ-CA) microfibers were developed using a two-step procedure involving ionotropic gelation (for the fiber formation) of κ-CA and its polyelectrolyte complexation with CHT (for the enhancement of fiber stability). The performance of the obtained fibers was assessed regarding their swelling and stability profiles, as well as their ability to carry and, subsequently, promote the outward release of microvascular-like endothelial cells (ECs), without compromising their viability and phenotype. Finally, the possibility of assembling and integrating these cell-laden fibers within a 3D hydrogel matrix containing osteoblast-like cells was evaluated. Overall, the obtained results demonstrate the suitability of the microsized κ-CA fibers to carry and deliver phenotypically apt microvascular-like ECs. Furthermore, it is shown that it is possible to assemble these cell-laden microsized fibers into 3D heterotypic hydrogels constructs. This in vitro 3D platform provides a versatile approach to investigate the interactions between multiple cell types in controlled settings, which may open up novel 3D in vitro culture techniques to better mimic the complexity of tissues. PMID:24963559

  9. Engineered Microenvironments to Direct Epidermal Stem Cell Behavior at Single-Cell Resolution.

    Science.gov (United States)

    Watt, Fiona M

    2016-09-26

    Mammalian epidermis is maintained through proliferation of stem cells and differentiation of their progeny. The balance between self-renewal and differentiation is controlled by a variety of interacting intrinsic and extrinsic factors. Although the nature of these interactions is complex, they can be modeled in a reductionist fashion by capturing single epidermal stem cells on micropatterned substrates and exposing them to individual stimuli, alone or in combination, over defined time points. These studies have shown that different extrinsic stimuli trigger a common outcome-initiation of terminal differentiation-by activating different signaling pathways and eliciting different transcriptional responses. PMID:27676433

  10. Protein-engineered block-copolymers as stem cell delivery vehicles

    Science.gov (United States)

    Heilshorn, Sarah

    2015-03-01

    Stem cell transplantation is a promising therapy for a myriad of debilitating diseases and injuries; however, current delivery protocols are inadequate. Transplantation by direct injection, which is clinically preferred for its minimal invasiveness, commonly results in less than 5% cell viability, greatly inhibiting clinical outcomes. We demonstrate that mechanical membrane disruption results in significant acute loss of viability at clinically relevant injection rates. As a strategy to protect cells from these damaging forces, we show that cell encapsulation within hydrogels of specific mechanical properties will significantly improve viability. Building on these fundamental studies, we have designed a reproducible, bio-resorbable, customizable hydrogel using protein-engineering technology. In our Mixing-Induced Two-Component Hydrogel (MITCH), network assembly is driven by specific and stoichiometric peptide-peptide binding interactions. By integrating protein science methodologies with simple polymer physics models, we manipulate the polypeptide chain interactions and demonstrate the direct ability to tune the network crosslinking density, sol-gel phase behavior, and gel mechanics. This is in contrast to many other physical hydrogels, where predictable tuning of bulk mechanics from the molecular level remains elusive due to the reliance on non-specific and non-stoichiometric chain interactions for network formation. Furthermore, the hydrogel network can be easily modified to deliver a variety of bioactive payloads including growth factors, peptide drugs, and hydroxyapatite nanoparticles. Through a series of in vitro and in vivo studies, we demonstrate that these materials may significantly improve transplanted stem cell retention and function.

  11. 3D Printing of Scaffold for Cells Delivery: Advances in Skin Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Deepti Singh

    2016-01-01

    Full Text Available Injury or damage to tissue and organs is a major health problem, resulting in about half of the world’s annual healthcare expenditure every year. Advances in the fields of stem cells (SCs and biomaterials processing have provided a tremendous leap for researchers to manipulate the dynamics between these two, and obtain a skin substitute that can completely heal the wounded areas. Although wound healing needs a coordinated interplay between cells, extracellular proteins and growth factors, the most important players in this process are the endogenous SCs, which activate the repair cascade by recruiting cells from different sites. Extra cellular matrix (ECM proteins are activated by these SCs, which in turn aid in cellular migrations and finally secretion of growth factors that can seal and heal the wounds. The interaction between ECM proteins and SCs helps the skin to sustain the rigors of everyday activity, and in an attempt to attain this level of functionality in artificial three-dimensional (3D constructs, tissue engineered biomaterials are fabricated using more advanced techniques such as bioprinting and laser assisted printing of the organs. This review provides a concise summary of the most recent advances that have been made in the area of polymer bio-fabrication using 3D bio printing used for encapsulating stem cells for skin regeneration. The focus of this review is to describe, in detail, the role of 3D architecture and arrangement of cells within this system that can heal wounds and aid in skin regeneration.

  12. THE FUNCTIONAL EFFECTIVENESS OF A CELL-ENGINEERED CONSTRUCT FOR THE REGENERATION OF ARTICULAR CARTILAGE

    Directory of Open Access Journals (Sweden)

    V. I. Sevastianov

    2015-01-01

    Full Text Available The aim of this study is an analysis of the functional effectiveness of a biomedical cell product consisting of a biopolymer microheterogeneous collagen-containing hydrogel (BMCH, human adipose-derived mesenchymal stromal cells (hADMSCs, and chondrogenic induction medium in the regeneration of articular cartilage. Materials and methods. The test model of the adjuvant arthritis was used (female Soviet Chinchilla rabbits with the further development into osteoarthrosis (OA combined with the clinical, biochemical, radiological, and histochemical trials. Results. On Day 92 of the OA model it has been found that the intra-articular introduction of a BMCH with hADMSCs into the left knee joint (n = 3 30 days after the OA modeling, as opposed to the right joint (negative control, n = 3, stimulates the regenerative processes of the cartilaginous tissue structure characterized by the formation of chondrocyte «columns», the emergence of isogenic groups in the intracellular matrix and the regeneration of its structure. Upon the intra-articular introduction of a BMCH (n = 3 such effects are markedly less pronounced. Conclusions. A significant regenerative potential of a cell-engineered construct of human articular tissue (CEC ATh has been proven. It is possible to presume that biostimulating properties of CEC ATh are due to the activating effect of a biomedical cell product on the stem cell migration processes from the surrounding tissue into the injured area with their subsequent differentiation. 

  13. Deterministic lateral displacement as a means to enrich large cells for tissue engineering.

    Science.gov (United States)

    Green, James V; Radisic, Milica; Murthy, Shashi K

    2009-11-01

    The enrichment or isolation of selected cell types from heterogeneous suspensions is required in the area of tissue engineering. State of the art techniques utilized for this separation include preplating and sieve-based approaches that have limited ranges of purity and variable yield. Here, we present a deterministic lateral displacement (DLD) microfluidic device that is capable of separating large epithelial cells (17.3 +/- 2.7 in diameter) from smaller fibroblast cells (13.7 +/- 3.0 microm in diameter) as a potential alternative approach. The mixed suspension examined is intended to represent the content of digested rat cardiac tissue, which contains equal proportions of cardiomyocyte (17.0 +/- 4.0 microm diameter) and nonmyocyte populations (12.0 +/- 3.0 microm diameter). High purity separation (>97%) of the larger cell type is achieved with 90% yield in a rapid and single-pass process. The significance of this work lies in the recognition that DLD design principles can be applied for the microfluidic enrichment of large cells, up to the 40 microm diameter level examined in this work.

  14. Engineering interaction between bone marrow derived endothelial cells and electrospun surfaces for artificial vascular graft applications.

    Science.gov (United States)

    Ahmed, Furqan; Dutta, Naba K; Zannettino, Andrew; Vandyke, Kate; Choudhury, Namita Roy

    2014-04-14

    The aim of this investigation was to understand and engineer the interactions between endothelial cells and the electrospun (ES) polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofiber surfaces and evaluate their potential for endothelialization. Elastomeric PVDF-HFP samples were electrospun to evaluate their potential use as small diameter artificial vascular graft scaffold (SDAVG) and compared with solvent cast (SC) PVDF-HFP films. We examined the consequences of fibrinogen adsorption onto the ES and SC samples for endothelialisation. Bone marrow derived endothelial cells (BMEC) of human origin were incubated with the test and control samples and their attachment, proliferation, and viability were examined. The nature of interaction of fibrinogen with SC and ES samples was investigated in detail using ELISA, XPS, and FTIR techniques. The pristine SC and ES PVDF-HFP samples displayed hydrophobic and ultrahydrophobic behavior and accordingly, exhibited minimal BMEC growth. Fibrinogen adsorbed SC samples did not significantly enhance endothelial cell binding or proliferation. In contrast, the fibrinogen adsorbed electrospun surfaces showed a clear ability to modulate endothelial cell behavior. This system also represents an ideal model system that enables us to understand the natural interaction between cells and their extracellular environment. The research reported shows potential of ES surfaces for artificial vascular graft applications. PMID:24564790

  15. Robot automated EMPT sheet welding

    OpenAIRE

    Pasquale, Pablo; Schäfer, Ralph

    2012-01-01

    Many industrial applications require sheet to sheet or sheet to tube joints. The electromagnetic pulse technology is capable to produce these kinds of joints. In literature many examples of sheet to sheet solid state welding between similar and dissimilar metals are presented and analyzed in detail. However, the most of the presented welding applications, which are very focussed on the academic level, are simple specimens for example for tensile test. These specimens are usuall...

  16. An impedance method for spatial sensing of 3D cell constructs – towards applications in tissue engineering

    DEFF Research Database (Denmark)

    Canali, Chiara; Mazzoni, Chiara; Larsen, Layla Bashir;

    2015-01-01

    ) cells were encapsulated in gelatin to form artificial 3D cell constructs and detected when placed in different positions inside large gelatin scaffolds. Taken together, these results open new perspectives for impedance-based sensing technologies for non-invasive monitoring in tissue engineering...

  17. Photovoltaic Engineering Testbed: A Facility for Space Calibration and Measurement of Solar Cells on the International Space Station

    Science.gov (United States)

    Landis, Geoffrey A.; Bailey, Sheila G.; Jenkins, Phillip; Sexton, J. Andrew; Scheiman, David; Christie, Robert; Charpie, James; Gerber, Scott S.; Johnson, D. Bruce

    2001-01-01

    The Photovoltaic Engineering Testbed ("PET") is a facility to be flown on the International Space Station to perform calibration, measurement, and qualification of solar cells in the space environment and then returning the cells to Earth for laboratory use. PET will allow rapid turnaround testing of new photovoltaic technology under AM0 conditions.

  18. Porous Chitosan Microcarriers for Large Scale Cultivation of Cells for Tissue Engineering: Fabrication and Evaluation

    Institute of Scientific and Technical Information of China (English)

    LU Guangyuan; ZHU Lin; KONG Lijun; ZHANG Ling; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2006-01-01

    Porous chitosan microspheres with diameters ranging from 180 μm to 280 μm were successfully prepared, using an anti-phase suspension method combined with temperature controlled freeze-extraction. The mean pore diameter could be regulated from 5 μm to 60 μm by varying the freezing temperature through the cooling rate. Results with in vitro chondrocyte cultures showed that cells could attach, proliferate, and spread on these porous microspheres as well as inside the microcarriers. The materials and cell cocultures were characterized using both optical and scanning electron microscopy. These results show that the porous chitosan microspheres are promising candidates for tissue culture for use as an injectable tissue engineering scaffold.

  19. Immobilized WNT Proteins Act as a Stem Cell Niche for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Molly Lowndes

    2016-07-01

    Full Text Available The timing, location, and level of WNT signaling are highly regulated during embryonic development and for the maintenance of adult tissues. Consequently the ability to provide a defined and directed source of WNT proteins is crucial to fully understand its role in tissue development and to mimic its activity in vitro. Here we describe a one-step immobilization technique to covalently bind WNT3A proteins as a basal surface with easy storage and long-lasting activity. We show that this platform is able to maintain adult and embryonic stem cells while also being adaptable for 3D systems. Therefore, this platform could be used for recapitulating specific stem cell niches with the goal of improving tissue engineering.

  20. Acute pergolide exposure stiffens engineered valve interstitial cell tissues and reduces contractility in vitro.

    Science.gov (United States)

    Capulli, Andrew K; MacQueen, Luke A; O'Connor, Blakely B; Dauth, Stephanie; Parker, Kevin Kit

    2016-01-01

    Medications based on ergoline-derived dopamine and serotonin agonists are associated with off-target toxicities that include valvular heart disease (VHD). Reports of drug-induced VHD resulted in the withdrawal of appetite suppressants containing fenfluramine and phentermine from the US market in 1997 and pergolide, a Parkinson's disease medication, in 2007. Recent evidence suggests that serotonin receptor activity affected by these medications modulates cardiac valve interstitial cell activation and subsequent valvular remodeling, which can lead to cardiac valve fibrosis and dysfunction similar to that seen in carcinoid heart disease. Failure to identify these risks prior to market and continued use of similar drugs reaffirm the need to improve preclinical evaluation of drug-induced VHD. Here, we present two complimentary assays to measure stiffness and contractile stresses generated by engineered valvular tissues in vitro. As a case study, we measured the effects of acute (24 h) pergolide exposure to engineered porcine aortic valve interstitial cell (AVIC) tissues. Pergolide exposure led to increased tissue stiffness, but it decreased both basal and active contractile tone stresses generated by AVIC tissues. Pergolide exposure also disrupted AVIC tissue organization (i.e., tissue anisotropy), suggesting that the mechanical properties and contractile functionality of these tissues are governed by their ability to maintain their structure. We expect further use of these assays to identify off-target drug effects that alter the phenotypic balance of AVICs, disrupt their ability to maintain mechanical homeostasis, and lead to VHD. PMID:27174867