WorldWideScience

Sample records for three-dimensional polymeric scaffold

  1. Direct fabrication of high-resolution three-dimensional polymeric scaffolds using electrohydrodynamic hot jet plotting

    International Nuclear Information System (INIS)

    Wei, Chuang; Dong, Jingyan

    2013-01-01

    This paper presents the direct three-dimensional (3D) fabrication of polymer scaffolds with sub-10 µm structures using electrohydrodynamic jet (EHD-jet) plotting of melted thermoplastic polymers. Traditional extrusion-based fabrication approaches of 3D periodic porous structures are very limited in their resolution, due to the excessive pressure requirement for extruding highly viscous thermoplastic polymers. EHD-jet printing has become a high-resolution alternative to other forms of nozzle deposition-based fabrication approaches by generating micro-scale liquid droplets or a fine jet through the application of a large electrical voltage between the nozzle and the substrate. In this study, we successfully apply EHD-jet plotting technology with melted biodegradable polymer (polycaprolactone, or PCL) for the fabrication of 2D patterns and 3D periodic porous scaffold structures in potential tissue engineering applications. Process conditions (e.g. electrical voltage, pressure, plotting speed) have been thoroughly investigated to achieve reliable jet printing of fine filaments. We have demonstrated for the first time that the EHD-jet plotting process is capable of the fabrication of 3D periodic structures with sub-10 µm resolution, which has great potential in advanced biomedical applications, such as cell alignment and guidance. (paper)

  2. Chitosan composite three dimensional macrospheric scaffolds for bone tissue engineering.

    Science.gov (United States)

    Vyas, Veena; Kaur, Tejinder; Thirugnanam, Arunachalam

    2017-11-01

    The present work deals with the fabrication of chitosan composite scaffolds with controllable and predictable internal architecture for bone tissue engineering. Chitosan (CS) based composites were developed by varying montmorillonite (MMT) and hydroxyapatite (HA) combinations to fabricate macrospheric three dimensional (3D) scaffolds by direct agglomeration of the sintered macrospheres. The fabricated CS, CS/MMT, CS/HA and CS/MMT/HA 3D scaffolds were characterized for their physicochemical, biological and mechanical properties. The XRD and ATR-FTIR studies confirmed the presence of the individual constituents and the molecular interaction between them, respectively. The reinforcement with HA and MMT showed reduced swelling and degradation rate. It was found that in comparison to pure CS, the CS/HA/MMT composites exhibited improved hemocompatibility and protein adsorption. The sintering of the macrospheres controlled the swelling ability of the scaffolds which played an important role in maintaining the mechanical strength of the 3D scaffolds. The CS/HA/MMT composite scaffold showed 14 folds increase in the compressive strength when compared to pure CS scaffolds. The fabricated scaffolds were also found to encourage the MG 63 cell proliferation. Hence, from the above studies it can be concluded that the CS/HA/MMT composite 3D macrospheric scaffolds have wider and more practical application in bone tissue regeneration applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Tailor-made three-dimensional hybrid scaffolds for cell cultures

    Energy Technology Data Exchange (ETDEWEB)

    Psycharakis, Stylianos; Melissinaki, Vasileia; Giakoumaki, Anastasia; Ranella, Anthi [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas, PO Box 1527, 711 10 Heraklion, Crete (Greece); Tosca, Androniki, E-mail: ranthi@iesl.forth.gr [Department of Medicine, University of Crete, 710 03 Heraklion, Crete (Greece)

    2011-08-15

    The construction of the ideal three-dimensional scaffold for cell culture is one of the most intriguing topics in tissue engineering. It has been shown that cells can be cultured on most organic biomimetic materials, which now are losing popularity in favour of novel, hybrid systems. In this study, a series of photosensitive sol-gel hybrid materials, based on silicon-zirconium and silicon-titanium oxides, have been investigated for their suitability in three-dimensional scaffold fabrication. These materials can be structured by two-photon polymerization, a laser-based technique allowing the fabrication of micrometre-size structures with submicron resolution. The work presented here examined the effect of the organic/inorganic composition of the materials on cell behaviour and the establishment of a 'cell-culture friendly' environment. This is vital for cell adhesion, growth and differentiation, as the organic part of the material provides the soft matrix for cell growth, whereas the inorganic component gives the mechanical stability and rigidity of the three-dimensional structures. In addition, the use of femtosecond laser structuring permits the fabrication of a wide range of mechanically stable scaffolds of different sizes and shapes to be tested in terms of cell viability, proliferation and orientation.

  4. Tailor-made three-dimensional hybrid scaffolds for cell cultures

    International Nuclear Information System (INIS)

    Psycharakis, Stylianos; Melissinaki, Vasileia; Giakoumaki, Anastasia; Ranella, Anthi; Tosca, Androniki

    2011-01-01

    The construction of the ideal three-dimensional scaffold for cell culture is one of the most intriguing topics in tissue engineering. It has been shown that cells can be cultured on most organic biomimetic materials, which now are losing popularity in favour of novel, hybrid systems. In this study, a series of photosensitive sol-gel hybrid materials, based on silicon-zirconium and silicon-titanium oxides, have been investigated for their suitability in three-dimensional scaffold fabrication. These materials can be structured by two-photon polymerization, a laser-based technique allowing the fabrication of micrometre-size structures with submicron resolution. The work presented here examined the effect of the organic/inorganic composition of the materials on cell behaviour and the establishment of a 'cell-culture friendly' environment. This is vital for cell adhesion, growth and differentiation, as the organic part of the material provides the soft matrix for cell growth, whereas the inorganic component gives the mechanical stability and rigidity of the three-dimensional structures. In addition, the use of femtosecond laser structuring permits the fabrication of a wide range of mechanically stable scaffolds of different sizes and shapes to be tested in terms of cell viability, proliferation and orientation.

  5. Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold

    Science.gov (United States)

    Farmer, Joseph C; Stadermann, Michael

    2013-11-12

    A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

  6. Three-dimensional printing of porous ceramic scaffolds for bone tissue engineering.

    Science.gov (United States)

    Seitz, Hermann; Rieder, Wolfgang; Irsen, Stephan; Leukers, Barbara; Tille, Carsten

    2005-08-01

    This article reports a new process chain for custom-made three-dimensional (3D) porous ceramic scaffolds for bone replacement with fully interconnected channel network for the repair of osseous defects from trauma or disease. Rapid prototyping and especially 3D printing is well suited to generate complex-shaped porous ceramic matrices directly from powder materials. Anatomical information obtained from a patient can be used to design the implant for a target defect. In the 3D printing technique, a box filled with ceramic powder is printed with a polymer-based binder solution layer by layer. Powder is bonded in wetted regions. Unglued powder can be removed and a ceramic green body remains. We use a modified hydroxyapatite (HA) powder for the fabrication of 3D printed scaffolds due to the safety of HA as biocompatible implantable material and efficacy for bone regeneration. The printed ceramic green bodies are consolidated at a temperature of 1250 degrees C in a high temperature furnace in ambient air. The polymeric binder is pyrolysed during sintering. The resulting scaffolds can be used in tissue engineering of bone implants using patient-derived cells that are seeded onto the scaffolds. This article describes the process chain, beginning from data preparation to 3D printing tests and finally sintering of the scaffold. Prototypes were successfully manufactured and characterized. It was demonstrated that it is possible to manufacture parts with inner channels with a dimension down to 450 microm and wall structures with a thickness down to 330 microm. The mechanical strength of dense test parts is up to 22 MPa. Copyright 2005 Wiley Periodicals, Inc.

  7. Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device.

    Science.gov (United States)

    Hamid, Q; Snyder, J; Wang, C; Timmer, M; Hammer, J; Guceri, S; Sun, W

    2011-09-01

    In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 °C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 °C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

  8. Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, Q; Snyder, J; Wang, C; Guceri, S; Sun, W [Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA (United States); Timmer, M; Hammer, J, E-mail: sunwei@drexel.edu [Advanced Technologies and Regenerative Medicine, Somerville, NJ (United States)

    2011-09-15

    In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 deg. C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 deg. C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

  9. Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device

    International Nuclear Information System (INIS)

    Hamid, Q; Snyder, J; Wang, C; Guceri, S; Sun, W; Timmer, M; Hammer, J

    2011-01-01

    In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 deg. C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 deg. C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

  10. [Three-dimensional parallel collagen scaffold promotes tendon extracellular matrix formation].

    Science.gov (United States)

    Zheng, Zefeng; Shen, Weiliang; Le, Huihui; Dai, Xuesong; Ouyang, Hongwei; Chen, Weishan

    2016-03-01

    To investigate the effects of three-dimensional parallel collagen scaffold on the cell shape, arrangement and extracellular matrix formation of tendon stem cells. Parallel collagen scaffold was fabricated by unidirectional freezing technique, while random collagen scaffold was fabricated by freeze-drying technique. The effects of two scaffolds on cell shape and extracellular matrix formation were investigated in vitro by seeding tendon stem/progenitor cells and in vivo by ectopic implantation. Parallel and random collagen scaffolds were produced successfully. Parallel collagen scaffold was more akin to tendon than random collagen scaffold. Tendon stem/progenitor cells were spindle-shaped and unified orientated in parallel collagen scaffold, while cells on random collagen scaffold had disorder orientation. Two weeks after ectopic implantation, cells had nearly the same orientation with the collagen substance. In parallel collagen scaffold, cells had parallel arrangement, and more spindly cells were observed. By contrast, cells in random collagen scaffold were disorder. Parallel collagen scaffold can induce cells to be in spindly and parallel arrangement, and promote parallel extracellular matrix formation; while random collagen scaffold can induce cells in random arrangement. The results indicate that parallel collagen scaffold is an ideal structure to promote tendon repairing.

  11. Dielectric spectroscopy for non-invasive monitoring of epithelial cell differentiation within three-dimensional scaffolds

    International Nuclear Information System (INIS)

    Daoud, Jamal; Tabrizian, Maryam; Asami, Koji; Rosenberg, Lawrence

    2012-01-01

    In this study, we introduce a cellular differentiation cellular model based on dielectric spectroscopy that characterizes epithelial differentiation processes. Non-invasive cellular monitoring was achieved within a three-dimensional microenvironment consisting of a cell-containing collagen I gel seeded onto microfabricated scaffolds. In this proof-of-concept investigation, Madin–Darby canine kidney cells were cultured within microfabricated, geometrically controlled scaffolds and allowed us to differentiate to hollow cyst-like structures. This transformation within the three-dimensional environment is monitored and characterized through dielectric spectroscopy while maintaining cell culture in vitro. (paper)

  12. Characterization of fabricated three dimensional scaffolds of bio ceramic-polymer composite via microstereolithography technique

    International Nuclear Information System (INIS)

    Marina Talib; Covington, J.A.; Bolarinwa, A.

    2013-01-01

    Full-text: Microstereolithography is a method used for rapid proto typing of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer per layer fabrication curing a liquid resin with UV-light or laser source. The aim of this project was to formulate photo curable polymer reinforced with synthesized calcium pyrophosphate (CPP), and to fabricate a 3D scaffolds with optimum mechanical properties for specific tissue engineering applications. The photo curable ceramic suspension was prepared with acrylate polyester, multifunctional acrylate monomer with the addition of 50-70 wt % of CPP, photo initiators and photo inhibitors. The 3D structure of disc (5 mm height x 4 mm diameter) was successfully fabricated using Envisiontec Perfactory3. They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. The density increased to more than 35 % and the dimensional shrinkage after sintering were 33 %. The discs were then subjected compressive measurement, biodegradation and bioactivity test. Morphology and CPP content of the sintered polymer was investigated with SEM and XRD, respectively. The addition of CPP coupled with high temperature sintering, had a significant effect on the compressive strength exhibited by the bio ceramic. The values are in the range of cancellous bone (2-4 MPa). In biodegradation and bioactivity test, the synthesized CPP induced the formation of apatite layer and its nucleation onto the composite surface. (author)

  13. Magnetic resonance imaging-three-dimensional printing technology fabricates customized scaffolds for brain tissue engineering

    Institute of Scientific and Technical Information of China (English)

    Feng Fu; Chong Chen; Sai Zhang; Ming-liang Zhao; Xiao-hong Li; Zhe Qin; Chao Xu; Xu-yi Chen; Rui-xin Li; Li-na Wang; Ding-wei Peng; Hong-tao Sun; Yue Tu

    2017-01-01

    Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer- aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine.

  14. [RESEARCH PROGRESS OF THREE-DIMENSIONAL PRINTING POROUS SCAFFOLDS FOR BONE TISSUE ENGINEERING].

    Science.gov (United States)

    Wu, Tianqi; Yang, Chunxi

    2016-04-01

    To summarize the research progress of several three-dimensional (3-D)-printing scaffold materials in bone tissue engineering. The recent domestic and international articles about 3-D printing scaffold materials were reviewed and summarized. Compared with conventional manufacturing methods, 3-D printing has distinctive advantages, such as enhancing the controllability of the structure and increasing the productivity. In addition to the traditional metal and ceramic scaffolds, 3-D printing scaffolds carrying seeding cells and tissue factors as well as scaffolds filling particular drugs for special need have been paid more and more attention. The development of 3-D printing porous scaffolds have revealed new perspectives in bone repairing. But it is still at the initial stage, more basic and clinical researches are still needed.

  15. Three dimensional changes in maxillary complete dentures immersed in water for seven days after polymerization

    Directory of Open Access Journals (Sweden)

    Shinsuke Sadamori

    2008-03-01

    Full Text Available The purpose of this study was to investigate the three dimensional changes in the fitting surface and artificial teeth of maxillary complete dentures which were fabricated using two different polymerizing processes: heat polymerization (HP and microwave polymerization (MP, after immersion in water for seven days. The amount of distortion in the molar region of the alveolar ridge was significantly different between HP and MP. However, the overall distortion of the dentures polymerized using both methods was similar. The distortion due to immersion in water for seven days compensated for the polymerization distortion, but the amount of distortion was very slight.

  16. Three-Dimensional Printing of Hollow-Struts-Packed Bioceramic Scaffolds for Bone Regeneration.

    Science.gov (United States)

    Luo, Yongxiang; Zhai, Dong; Huan, Zhiguang; Zhu, Haibo; Xia, Lunguo; Chang, Jiang; Wu, Chengtie

    2015-11-04

    Three-dimensional printing technologies have shown distinct advantages to create porous scaffolds with designed macropores for application in bone tissue engineering. However, until now, 3D-printed bioceramic scaffolds only possessing a single type of macropore have been reported. Generally, those scaffolds with a single type of macropore have relatively low porosity and pore surfaces, limited delivery of oxygen and nutrition to surviving cells, and new bone tissue formation in the center of the scaffolds. Therefore, in this work, we present a useful and facile method for preparing hollow-struts-packed (HSP) bioceramic scaffolds with designed macropores and multioriented hollow channels via a modified coaxial 3D printing strategy. The prepared HSP scaffolds combined high porosity and surface area with impressive mechanical strength. The unique hollow-struts structures of bioceramic scaffolds significantly improved cell attachment and proliferation and further promoted formation of new bone tissue in the center of the scaffolds, indicating that HSP ceramic scaffolds can be used for regeneration of large bone defects. In addition, the strategy can be used to prepare other HSP ceramic scaffolds, indicating a universal application for tissue engineering, mechanical engineering, catalysis, and environmental materials.

  17. Customized biomimetic scaffolds created by indirect three-dimensional printing for tissue engineering

    International Nuclear Information System (INIS)

    Lee, Ju-Yeon; Choi, Bogyu; Wu, Benjamin; Lee, Min

    2013-01-01

    Three-dimensional printing (3DP) is a rapid prototyping technique that can create complex 3D structures by inkjet printing of a liquid binder onto powder biomaterials for tissue engineering scaffolds. Direct fabrication of scaffolds from 3DP, however, imposes a limitation on material choices by manufacturing processes. In this study, we report an indirect 3DP approach wherein a positive replica of desired shapes was printed using gelatin particles, and the final scaffold was directly produced from the printed mold. To create patient-specific scaffolds that match precisely to a patient's external contours, we integrated our indirect 3DP technique with imaging technologies and successfully created custom scaffolds mimicking human mandibular condyle using polycaprolactone and chitosan for potential osteochondral tissue engineering. To test the ability of the technique to precisely control the internal morphology of the scaffolds, we created orthogonal interconnected channels within the scaffolds using computer-aided-design models. Because very few biomaterials are truly osteoinductive, we modified inert 3D printed materials with bioactive apatite coating. The feasibility of these scaffolds to support cell growth was investigated using bone marrow stromal cells (BMSC). The BMSCs showed good viability in the scaffolds, and the apatite coating further enhanced cellular spreading and proliferation. This technique may be valuable for complex scaffold fabrication. (paper)

  18. The development of a three-dimensional scaffold for ex vivo biomimicry of human acute myeloid leukaemia.

    Science.gov (United States)

    Blanco, Teresa Mortera; Mantalaris, Athanasios; Bismarck, Alexander; Panoskaltsis, Nicki

    2010-03-01

    Acute myeloid leukaemia (AML) is a cancer of haematopoietic cells that develops in three-dimensional (3-D) bone marrow niches in vivo. The study of AML has been hampered by lack of appropriate ex vivo models that mimic this microenvironment. We hypothesised that fabrication and optimisation of suitable biomimetic scaffolds for culturing leukaemic cells ex vivo might facilitate the study of AML in its native 3-D niche. We evaluated the growth of three leukaemia subtype-specific cell lines, K-562, HL60 and Kasumi-6, on highly porous scaffolds fabricated from biodegradable and non-biodegradable polymeric materials, such as poly (L-lactic-co-glycolic acid) (PLGA), polyurethane (PU), poly (methyl-methacrylate), poly (D, L-lactade), poly (caprolactone), and polystyrene. Our results show that PLGA and PU supported the best seeding efficiency and leukaemic growth. Furthermore, the PLGA and PU scaffolds were coated with extracellular matrix (ECM) proteins, collagen type I (62.5 or 125 microg/ml) and fibronectin (25 or 50 microg/ml) to provide biorecognition signals. The 3 leukaemia subtype-specific lines grew best on PU scaffolds coated with 62.5 microg/ml collagen type I over 6 weeks in the absence of exogenous growth factors. In conclusion, PU-collagen scaffolds may provide a practical model to study the biology and treatment of primary AML in an ex vivo mimicry. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  19. The fabrication and cell culture of three-dimensional rolled scaffolds with complex micro-architectures

    International Nuclear Information System (INIS)

    Liu Yaxiong; Li Xiao; Qu Xiaoli; Zhu Lin; He Jiankang; Zhao Qian; Wu Wanquan; Li Dichen

    2012-01-01

    Cell cultures for tissue engineering are traditionally prepared on two-dimensional or three-dimensional scaffolds with simple pores; however, this limits mass transportation, which is necessary for cell viability and function. In this paper, an innovative method is proposed for fabricating porous scaffolds with designed complex micro-architectures. Channels devised by computer-aided design were used to simulate features of blood vessels in native rat liver. Rapid prototyping and microreplication were used to produce a negative polydimethylsiloxane mold, and then a planar porous scaffold with predefined microchannel parameters was obtained by freeze-drying a silk fibroin/gelatin solution of an optimized concentration. After seeding with rat primary hepatocytes, the planar scaffold was rolled up to build spatial channels. By reconstructing the three-dimensional channel model in the scaffold in the form of micro-computed topography data and observing the cross-sections of the scroll, we confirmed that the bent channels were still interconnected, with restricted deviations. A comparison of the primary hepatocyte culture in the scaffolds with and without the devised channels proved that our design influenced cell organization and improved cell survival and proliferation. This method can be used for the construction of complex tissues for implantation and for culturing cells in vitro for biological tests and observations.

  20. Indirect three-dimensional printing of synthetic polymer scaffold based on thermal molding process

    International Nuclear Information System (INIS)

    Park, Jeong Hun; Jung, Jin Woo; Cho, Dong-Woo; Kang, Hyun-Wook

    2014-01-01

    One of the major issues in tissue engineering has been the development of three-dimensional (3D) scaffolds, which serve as a structural template for cell growth and extracellular matrix formation. In scaffold-based tissue engineering, 3D printing (3DP) technology has been successfully applied for the fabrication of complex 3D scaffolds by using both direct and indirect techniques. In principle, direct 3DP techniques rely on the straightforward utilization of the final scaffold materials during the actual scaffold fabrication process. In contrast, indirect 3DP techniques use a negative mold based on a scaffold design, to which the desired biomaterial is cast and then sacrificed to obtain the final scaffold. Such indirect 3DP techniques generally impose a solvent-based process for scaffold fabrication, resulting in a considerable increase in the fabrication time and poor mechanical properties. In addition, the internal architecture of the resulting scaffold is affected by the properties of the biomaterial solution. In this study, we propose an advanced indirect 3DP technique using projection-based micro-stereolithography and an injection molding system (IMS) in order to address these challenges. The scaffold was fabricated by a thermal molding process using IMS to overcome the limitation of the solvent-based molding process in indirect 3DP techniques. The results indicate that the thermal molding process using an IMS has achieved a substantial reduction in scaffold fabrication time and has also provided the scaffold with higher mechanical modulus and strength. In addition, cell adhesion and proliferation studies have indicated no significant difference in cell activity between the scaffolds prepared by solvent-based and thermal molding processes. (paper)

  1. Fabrication and Characterization of three dimensional Scaffolds for tissue engineering application via microstereolithography technique

    International Nuclear Information System (INIS)

    Marina Talib; Covington, J.A.; Dove, A.; Bolarinwa, A.; Grover, L.

    2012-01-01

    Microstereolithography is a method used for rapid proto typing of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer-per-layer fabrication curing a liquid resin with UV-light or laser source. However, the use of stereo lithography in tissue engineering has not been significantly explored possibly due to the lack of commercially available implantable or biocompatible materials from the SL industry. This study seeks to develop a range of new bio-compatible/degradable materials that are compatible with a commercial 3D direct manufacture system (envisionTEC Desktop). Firstly, a selection of multifunctional polymer and calcium phosphate were studied in order to formulate biodegradable photo polymer resin for specific tissue engineering applications. A 3D structure was successfully fabricated from the formulated photo curable resins. The photo polymer of ceramic suspension was prepared with the addition of 50-70 wt % of calcium pyrophosphate (CPP) and hydroxyapatite (HA). They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. Mechanical properties, morphology and calcium phosphate content of the sintered polymers were characterised and investigated with SEM and XRD, respectively. The addition of calcium phosphate coupled with high temperature sintering, had a significant effect on the mechanical properties exhibited by the bio ceramic. The successful fabrication of novel bio ceramic polymer composite with MSL technique offers the possibility of designing complex tissue scaffolds with optimum mechanical properties for specific tissue engineering applications. (author)

  2. A healing method of tympanic membrane perforations using three-dimensional porous chitosan scaffolds.

    Science.gov (United States)

    Kim, Jangho; Kim, Seung Won; Choi, Seong Jun; Lim, Ki Taek; Lee, Jong Bin; Seonwoo, Hoon; Choung, Pill-Hoon; Park, Keehyun; Cho, Chong-Su; Choung, Yun-Hoon; Chung, Jong Hoon

    2011-11-01

    Both surgical tympanoplasty and paper patch grafts are frequently procedured to heal tympanic membrane (TM) perforation or chronic otitis media, despite their many disadvantages. In this study, we report a new healing method of TM perforation by using three-dimensional (3D) porous chitosan scaffolds (3D chitosan scaffolds) as an alternative method to surgical treatment or paper patch graft. Various 3D chitosan scaffolds were prepared; and the structural characteristics, mechanical property, in vitro biocompatibility, and healing effects of the 3D chitosan scaffolds as an artificial TM in in vivo animal studies were investigated. A 3D chitosan scaffold of 5 wt.% chitosan concentration showed good proliferation of TM cells in an in vitro study, as well as suitable structural characteristics and mechanical property, as compared with either 1% or 3% chitosan. In in vivo animal studies, 3D chitosan scaffold were able to migrate through the pores and surfaces of TM cells, thus leading to more effective TM regeneration than paper patch technique. Histological observations demonstrated that the regenerated TM with the 3D chitosan scaffold consisted of three (epidermal, connective tissue, and mucosal) layers and were thicker than normal TMs. The 3D chitosan scaffold technique may be an optimal healing method used in lieu of surgical tympanoplasty in certain cases to heal perforated TMs.

  3. Preparation and characterization of three-dimensional scaffolds based on hydroxypropyl chitosan-graft-graphene oxide.

    Science.gov (United States)

    Sivashankari, P R; Moorthi, A; Abudhahir, K Mohamed; Prabaharan, M

    2018-04-15

    Hydroxypropyl chitosan (HPCH), a water soluble derivative of chitosan, is widely considered for tissue engineering and wound healing applications due to its biocompatibility and biodegradability. Graphene oxide (GO) is a carbon-based nanomaterial which is capable of imparting desired properties to the scaffolds. Hence, the integration of GO into HPCH could allow for the production of HPCH-based scaffolds with improved swelling character, mechanical strength, and stability aimed at being used in tissue engineering. In this study, hydroxypropyl chitosan-graft-graphene oxide (HPCH-g-GO) with varying GO content (0.5, 1, 3 and 4wt.%) was prepared using HPCH and GO as a tissue engineering scaffold material. The formation of HPCH-g-GO was confirmed by FTIR and XRD analysis. Using the HPCH-g-GO as a matrix material and glutaraldehyde as a crosslinking agent, the three dimensional (3D) porous scaffolds were fabricated by the freeze-drying method. The HPCH-g-GO scaffolds exhibited uniform porosity as observed in SEM analysis. The pore size and porosity reduced as the content of GO was increased. These scaffolds presented good swelling capacity, water retention ability, mechanical strength and in vitro degradation properties. The HPCH-g-GO scaffolds irrespective of their GO content demonstrated good cell viability when compared to control. Altogether, these results suggest that HPCH-g-GO scaffolds can be used as potential tissue engineering material. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Three-dimensional visualization and characterization of polymeric self-assemblies by Transmission Electron Microtomography

    NARCIS (Netherlands)

    H. Jinnai (Hiroshi); T. Higuchi (Takeshi); X. Zhuge (Jason); A. Kumamoto (Akihito); K.J. Batenburg (Joost); Y. Ikuhara (Yuichi)

    2017-01-01

    textabstractSelf-assembling structures and their dynamical processes in polymeric systems have been investigated using three-dimensional transmission electron microscopy (3D-TEM). Block copolymers (BCPs) self-assemble into nanoscale periodic structures called microphase-separated structures, a deep

  5. Macroporous Hydrogel Scaffolds for Three-Dimensional Cell Culture and Tissue Engineering.

    Science.gov (United States)

    Fan, Changjiang; Wang, Dong-An

    2017-10-01

    Hydrogels have been promising candidate scaffolds for cell delivery and tissue engineering due to their tissue-like physical properties and capability for homogeneous cell loading. However, the encapsulated cells are generally entrapped and constrained in the submicron- or nanosized gel networks, seriously limiting cell growth and tissue formation. Meanwhile, the spatially confined settlement inhibits attachment and spreading of anchorage-dependent cells, leading to their apoptosis. In recent years, macroporous hydrogels have attracted increasing attention in use as cell delivery vehicles and tissue engineering scaffolds. The introduction of macropores within gel scaffolds not only improves their permeability for better nutrient transport but also creates space/interface for cell adhesion, proliferation, and extracellular matrix deposition. Herein, we will first review the development of macroporous gel scaffolds and outline the impact of macropores on cell behaviors. In the first part, the advantages and challenges of hydrogels as three-dimensional (3D) cell culture scaffolds will be described. In the second part, the fabrication of various macroporous hydrogels will be presented. Third, the enhancement of cell activities within macroporous gel scaffolds will be discussed. Finally, several crucial factors that are envisaged to propel the improvement of macroporous gel scaffolds are proposed for 3D cell culture and tissue engineering.

  6. Facile fabrication of the porous three-dimensional regenerated silk fibroin scaffolds

    International Nuclear Information System (INIS)

    Cao, Zhengbing; Wen, Jianchuan; Yao, Jinrong; Chen, Xin; Ni, Yusu; Shao, Zhengzhong

    2013-01-01

    In the present work, we report a new facile method to fabricate porous three-dimensional regenerated silk fibroin (RSF) scaffolds through n-butanol- and freezing-induced conformation transition and phase separation. The effects of RSF concentration, freezing temperature and n-butanol addition on the microstructure, the secondary structures of silk fibroin and apparent mechanical properties of the RSF scaffolds were investigated by SEM, 13 C CP-MAS NMR spectra and mechanical testing, respectively. By adjusting the RSF concentration and n-butanol addition, the pore size of the scaffold could be controlled in the range from of 10 μm to 350 μm with 84%–98% of porosity. The tensile strength of the wet scaffold reached the maximum of 755.2 ± 33.6 kPa when the concentration of RSF solution was increased to 15% w/w. Moreover, post-treatment with ethanol further induced conformation transition of RSF from random coil or helix to β-sheet. The porous scaffolds prepared by this facile and energy-saving method with good biocompatibility will have great potential for application in tissue engineering. Highlights: • A new facile and energy-saving method to fabricate porous silk fibroin scaffolds; • Freeze-drying step (a typical high energy consuming process) is unnecessary; • Morphology and mechanical properties of scaffolds were easily controlled; • Ethanol post-treatment can be used to tune the degradation behavior

  7. Three-Dimensional Elastomeric Scaffolds Designed with Cardiac-Mimetic Structural and Mechanical Features

    Science.gov (United States)

    Neal, Rebekah A.; Jean, Aurélie; Park, Hyoungshin; Wu, Patrick B.; Hsiao, James; Engelmayr, George C.; Langer, Robert

    2013-01-01

    Tissue-engineered constructs, at the interface of material science, biology, engineering, and medicine, have the capacity to improve outcomes for cardiac patients by providing living cells and degradable biomaterials that can regenerate the native myocardium. With an ultimate goal of both delivering cells and providing mechanical support to the healing heart, we designed three-dimensional (3D) elastomeric scaffolds with (1) stiffnesses and anisotropy mimicking explanted myocardial specimens as predicted by finite-element (FE) modeling, (2) systematically varied combinations of rectangular pore pattern, pore aspect ratio, and strut width, and (3) structural features approaching tissue scale. Based on predicted mechanical properties, three scaffold designs were selected from eight candidates for fabrication from poly(glycerol sebacate) by micromolding from silicon wafers. Large 20×20 mm scaffolds with high aspect ratio features (5:1 strut height:strut width) were reproducibly cast, cured, and demolded at a relatively high throughput. Empirically measured mechanical properties demonstrated that scaffolds were cardiac mimetic and validated FE model predictions. Two-layered scaffolds providing fully interconnected pore networks were fabricated by layer-by-layer assembly. C2C12 myoblasts cultured on one-layered scaffolds exhibited specific patterns of cell elongation and interconnectivity that appeared to be guided by the scaffold pore pattern. Neonatal rat heart cells cultured on two-layered scaffolds for 1 week were contractile, both spontaneously and in response to electrical stimulation, and expressed sarcomeric α-actinin, a cardiac biomarker. This work not only demonstrated several scaffold designs that promoted functional assembly of rat heart cells, but also provided the foundation for further computational and empirical investigations of 3D elastomeric scaffolds for cardiac tissue engineering. PMID:23190320

  8. A novel three-dimensional scaffold for regenerative endodontics: materials and biological characterizations.

    Science.gov (United States)

    Bottino, Marco C; Yassen, Ghaeth H; Platt, Jeffrey A; Labban, Nawaf; Windsor, L Jack; Spolnik, Kenneth J; Bressiani, Ana H A

    2015-11-01

    An electrospun nanocomposite fibrous material holds promise as a scaffold, as well as a drug-delivery device to aid in root maturogenesis and the regeneration of the pulp-dentine complex. A novel three-dimensional (3D) nanocomposite scaffold composed of polydioxanone (PDS II®) and halloysite nanotubes (HNTs) was designed and fabricated by electrospinning. Morphology, structure, mechanical properties and cell compatibility studies were carried out to evaluate the effects of HNTs incorporation (0.5-10 wt% relative to PDS w/w). Overall, a 3D porous network was seen in the different fabricated electrospun scaffolds, regardless of the HNT content. The incorporation of HNTs at 10 wt% led to a significant (p endodontics. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Electrospinning PCL Scaffolds Manufacture for Three-Dimensional Breast Cancer Cell Culture

    Directory of Open Access Journals (Sweden)

    Marc Rabionet

    2017-08-01

    Full Text Available In vitro cell culture is traditionally performed within two-dimensional (2D environments, providing a quick and cheap way to study cell properties in a laboratory. However, 2D systems differ from the in vivo environment and may not mimic the physiological cell behavior realistically. For instance, 2D culture models are thought to induce cancer stem cells (CSCs differentiation, a rare cancer cell subpopulation responsible for tumor initiation and relapse. This fact hinders the development of therapeutic strategies for tumors with a high relapse percentage, such as triple negative breast cancer (TNBC. Thus, three-dimensional (3D scaffolds have emerged as an attractive alternative to monolayer culture, simulating the extracellular matrix structure and maintaining the differentiation state of cells. In this work, scaffolds were fabricated through electrospinning different poly(ε-caprolactone-acetone solutions. Poly(ε-caprolactone (PCL meshes were seeded with triple negative breast cancer (TNBC cells and 15% PCL scaffolds displayed significantly (p < 0.05 higher cell proliferation and elongation than the other culture systems. Moreover, cells cultured on PCL scaffolds exhibited higher mammosphere forming capacity and aldehyde dehydrogenase activity than 2D-cultured cells, indicating a breast CSCs enrichment. These results prove the powerful capability of electrospinning technology in terms of poly(ε-caprolactone nanofibers fabrication. In addition, this study has demonstrated that electrospun 15% PCL scaffolds are suitable tools to culture breast cancer cells in a more physiological way and to expand the niche of breast CSCs. In conclusion, three-dimensional cell culture using PCL scaffolds could be useful to study cancer stem cell behavior and may also trigger the development of new specific targets against such malignant subpopulation.

  10. Bone regeneration by means of a three-dimensional printed scaffold in a rat cranial defect.

    Science.gov (United States)

    Kwon, Doo Yeon; Park, Ji Hoon; Jang, So Hee; Park, Joon Yeong; Jang, Ju Woong; Min, Byoung Hyun; Kim, Wan-Doo; Lee, Hai Bang; Lee, Junhee; Kim, Moon Suk

    2018-02-01

    Recently, computer-designed three-dimensional (3D) printing techniques have emerged as an active research area with almost unlimited possibilities. In this study, we used a computer-designed 3D scaffold to drive new bone formation in a bone defect. Poly-L-lactide (PLLA) and bioactive β-tricalcium phosphate (TCP) were simply mixed to prepare ink. PLLA + TCP showed good printability from the micronozzle and solidification within few seconds, indicating that it was indeed printable ink for layer-by-layer printing. In the images, TCP on the surface of (and/or inside) PLLA in the printed PLLA + TCP scaffold looked dispersed. MG-63 cells (human osteoblastoma) adhered to and proliferated well on the printed PLLA + TCP scaffold. To assess new bone formation in vivo, the printed PLLA + TCP scaffold was implanted into a full-thickness cranial bone defect in rats. The new bone formation was monitored by microcomputed tomography and histological analysis of the in vivo PLLA + TCP scaffold with or without MG-63 cells. The bone defect was gradually spontaneously replaced with new bone tissues when we used both bioactive TCP and MG-63 cells in the PLLA scaffold. Bone formation driven by the PLLA + TCP30 scaffold with MG-63 cells was significantly greater than that in other experimental groups. Furthermore, the PLLA + TCP scaffold gradually degraded and matched well the extent of the gradual new bone formation on microcomputed tomography. In conclusion, the printed PLLA + TCP scaffold effectively supports new bone formation in a cranial bone defect. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Three-dimensional piezoelectric fibrous scaffolds selectively promote mesenchymal stem cell differentiation.

    Science.gov (United States)

    Damaraju, Sita M; Shen, Yueyang; Elele, Ezinwa; Khusid, Boris; Eshghinejad, Ahmad; Li, Jiangyu; Jaffe, Michael; Arinzeh, Treena Livingston

    2017-12-01

    The discovery of electric fields in biological tissues has led to efforts in developing technologies utilizing electrical stimulation for therapeutic applications. Native tissues, such as cartilage and bone, exhibit piezoelectric behavior, wherein electrical activity can be generated due to mechanical deformation. Yet, the use of piezoelectric materials have largely been unexplored as a potential strategy in tissue engineering, wherein a piezoelectric biomaterial acts as a scaffold to promote cell behavior and the formation of large tissues. Here we show, for the first time, that piezoelectric materials can be fabricated into flexible, three-dimensional fibrous scaffolds and can be used to stimulate human mesenchymal stem cell differentiation and corresponding extracellular matrix/tissue formation in physiological loading conditions. Piezoelectric scaffolds that exhibit low voltage output, or streaming potential, promoted chondrogenic differentiation and piezoelectric scaffolds with a high voltage output promoted osteogenic differentiation. Electromechanical stimulus promoted greater differentiation than mechanical loading alone. Results demonstrate the additive effect of electromechanical stimulus on stem cell differentiation, which is an important design consideration for tissue engineering scaffolds. Piezoelectric, smart materials are attractive as scaffolds for regenerative medicine strategies due to their inherent electrical properties without the need for external power sources for electrical stimulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Quantitative determination of residual 1,4-dioxane in three-dimensional printed bone scaffold

    Directory of Open Access Journals (Sweden)

    Ling Li

    2018-04-01

    Full Text Available Summary: Background/Objective: A novel porous scaffold poly (lactide-co-glycolide and tricalcium phosphate (PLGA/TCP was developed by three-dimensional printing technology for bone defect repair. As a Class 2 solvent with less severe toxicity, content of residual 1,4-dioxane in this newly developed scaffold should be rigorously controlled when it is translated to clinical use. In this study, a headspace gas chromatography-mass spectrometric (HS-GC-MS method and related testing protocol were developed for quantitative determination of 1,4-dioxane in the PLGA/TCP composite scaffolds. Methods: Matrix effect analysis was used to optimise the pretreatment method of the scaffolds. Then, the procedure for testing 1,4-dioxane using HS-GC-MS was set up. The accuracy, precision, and robustness of this newly developed quantitative method were also validated before quantification of 1,4-dioxane in the scaffolds with different drying procedures. Results: Dimethyl formamide (DMF was the optimal solvent for dissolving scaffolds for GC-MS with proper sensitivity and without matrix effect. Then, the optimised procedure was determined as: the scaffolds were dissolved in DMF and kept at 90°C for 40 minutes, separated on a HP-5MS column, and detected by mass spectroscopy. Recovery experiments gave 97.9–100.7% recovery for 1,4-dioxane. The linear range for 1,4-dioxane was determined as 1–40 ppm with linear correlation coefficient ≥ 0.9999. Intraday and interday precision was determined as being within relative standard deviation of below 0.68%. The passable drying procedure was related to lyophilising (−50°C, 50 Pa the scaffolds for 2 days and drying in vacuum (50 Pa for 7 days. Conclusion: This is the first quantitative method established to test 1,4-dixoane in a novel scaffold. This method was validated with good accuracy and reproducibility, and met the methodological requirements of the Guideline 9101 documented in the Chinese Pharmacopoeia 2015

  13. Direct write printing of three-dimensional ZrO2 biological scaffolds

    International Nuclear Information System (INIS)

    Li, Ya-yun; Li, Long-tu; Li, Bo

    2015-01-01

    Graphical abstract: Three-dimensional (3D) zirconium dioxide (ZrO 2 ) scaffolds have been fabricated for biological engineering by direct write printing method. The water-based ZrO 2 ink with a solid content fraction of 70 wt% was deposited through a fine nozzle on the substrate by a layer-by-layer sequence to produce the 3D microperiodic structures. Under a microscope, the proliferation of HCT116 cells can be observed around the 3D ZrO 2 scaffolds. 3D porous internal architecture is beneficial for cell growth by providing more locations for cell attachment and proliferation. The largest value of compressive strength reached 10 MPa, which is more than that of the hydroxyapatite (HAp) scaffold. The ability of printing 3D scaffolds with the high precise control of their internal architecture is the unique characteristics performed by the direct write technique, which will provide potential application of biomaterials and tissue engineering scaffolds. (a) Top view of the sintered 3D woodpile ZrO 2 scaffold; (b) top view of the sintered 3D cylindrical ZrO 2 scaffold. - Highlights: • 3D cylindrical and woodpile ZrO 2 scaffolds were fabricated by direct write printing method. • The compressive strength of the sample with porosity about 63% was 8 MPa. • The compressive strength of the porosity 55% sample was 10 MPa. • 3D porous ZrO 2 scaffolds with interconnected architecture are beneficial for cell attachment and proliferation. - Abstract: Three-dimensional (3D) zirconium dioxide (ZrO 2 ) scaffolds have been fabricated for biological engineering by direct write printing method. The water-based ZrO 2 ink with a solid content fraction of 70 wt% was deposited through a fine nozzle on the substrate by a layer-by-layer sequence to produce the 3D microperiodic structures. The preparation and the rheological behavior of this ink, as well as the principles of the direct write printing process were investigated systematically. Sintered at 1250 °C for 4 h was the optimal

  14. A new method of fabricating a blend scaffold using an indirect three-dimensional printing technique

    International Nuclear Information System (INIS)

    Jung, Jin Woo; Lee, Hyungseok; Hong, Jung Min; Park, Jeong Hun; Cho, Dong-Woo; Shim, Jung Hee; Choi, Tae Hyun

    2015-01-01

    Due to its simplicity and effectiveness, the physical blending of polymers is considered to be a practical strategy for developing a versatile scaffold having desirable mechanical and biochemical properties. In the present work, an indirect three-dimensional (i3D) printing technique was proposed to fabricate a 3D free-form scaffold using a blend of immiscible materials, such as polycaprolactone (PCL) and gelatin. The i3D printing technique includes 3D printing of a mold and a sacrificial molding process. PCL/chloroform and gelatin/water were physically mixed to prepare the blend solution, which was subsequently injected into the cavity of a 3D printed mold. After solvent removal and gelatin cross-linking, the mold was dissolved to obtain a PCL–gelatin (PG) scaffold, with a specific 3D structure. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that PCL masses and gelatin fibers in the PG scaffold homogenously coexisted without chemical bonding. Compression tests confirmed that gelatin incorporation into the PCL enhanced its mechanical flexibility and softness, to the point of being suitable for soft-tissue engineering, as opposed to pure PCL. Human adipose-derived stem cells, cultured on a PG scaffold, exhibited enhanced in vitro chondrogenic differentiation and tissue formation, compared with those on a PCL scaffold. The i3D printing technique can be used to blend a variety of materials, facilitating 3D scaffold fabrication for specific tissue regeneration. Furthermore, this convenient and versatile technique may lead to wider application of 3D printing in tissue engineering. (paper)

  15. A new method of fabricating a blend scaffold using an indirect three-dimensional printing technique.

    Science.gov (United States)

    Jung, Jin Woo; Lee, Hyungseok; Hong, Jung Min; Park, Jeong Hun; Shim, Jung Hee; Choi, Tae Hyun; Cho, Dong-Woo

    2015-11-03

    Due to its simplicity and effectiveness, the physical blending of polymers is considered to be a practical strategy for developing a versatile scaffold having desirable mechanical and biochemical properties. In the present work, an indirect three-dimensional (i3D) printing technique was proposed to fabricate a 3D free-form scaffold using a blend of immiscible materials, such as polycaprolactone (PCL) and gelatin. The i3D printing technique includes 3D printing of a mold and a sacrificial molding process. PCL/chloroform and gelatin/water were physically mixed to prepare the blend solution, which was subsequently injected into the cavity of a 3D printed mold. After solvent removal and gelatin cross-linking, the mold was dissolved to obtain a PCL-gelatin (PG) scaffold, with a specific 3D structure. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that PCL masses and gelatin fibers in the PG scaffold homogenously coexisted without chemical bonding. Compression tests confirmed that gelatin incorporation into the PCL enhanced its mechanical flexibility and softness, to the point of being suitable for soft-tissue engineering, as opposed to pure PCL. Human adipose-derived stem cells, cultured on a PG scaffold, exhibited enhanced in vitro chondrogenic differentiation and tissue formation, compared with those on a PCL scaffold. The i3D printing technique can be used to blend a variety of materials, facilitating 3D scaffold fabrication for specific tissue regeneration. Furthermore, this convenient and versatile technique may lead to wider application of 3D printing in tissue engineering.

  16. Development of an acellular tumor extracellular matrix as a three-dimensional scaffold for tumor engineering.

    Directory of Open Access Journals (Sweden)

    Wei-Dong Lü

    Full Text Available Tumor engineering is defined as the construction of three-dimensional (3D tumors in vitro with tissue engineering approaches. The present 3D scaffolds for tumor engineering have several limitations in terms of structure and function. To get an ideal 3D scaffold for tumor culture, A549 human pulmonary adenocarcinoma cells were implanted into immunodeficient mice to establish xenotransplatation models. Tumors were retrieved at 30-day implantation and sliced into sheets. They were subsequently decellularized by four procedures. Two decellularization methods, Tris-Trypsin-Triton multi-step treatment and sodium dodecyl sulfate (SDS treatment, achieved complete cellular removal and thus were chosen for evaluation of histological and biochemical properties. Native tumor tissues were used as controls. Human breast cancer MCF-7 cells were cultured onto the two 3D scaffolds for further cell growth and growth factor secretion investigations, with the two-dimensional (2D culture and cells cultured onto the Matrigel scaffolds used as controls. Results showed that Tris-Trypsin-Triton multi-step treated tumor sheets had well-preserved extracellular matrix structures and components. Their porosity was increased but elastic modulus was decreased compared with the native tumor samples. They supported MCF-7 cell repopulation and proliferation, as well as expression of growth factors. When cultured within the Tris-Trypsin-Triton treated scaffold, A549 cells and human colorectal adenocarcinoma cells (SW-480 had similar behaviors to MCF-7 cells, but human esophageal squamous cell carcinoma cells (KYSE-510 had a relatively slow cell repopulation rate. This study provides evidence that Tris-Trypsin-Triton treated acellular tumor extracellular matrices are promising 3D scaffolds with ideal spatial arrangement, biomechanical properties and biocompatibility for improved modeling of 3D tumor microenvironments.

  17. A comparison of three dimensional change in maxillary complete dentures between conventional heat polymerizing and microwave polymerizing techniques

    Directory of Open Access Journals (Sweden)

    Shinsuke Sadamori

    2007-03-01

    Full Text Available The purpose of this study was to measure and compare two different polymerizing processes, heat polymerizing (HP and microwave polymerizing (MP, on the three dimensional changes in the fitting surface and artificial teeth of maxillary complete dentures. A threedimensional coordinate measurement system was used to record distortion of the specimens. The distortion of the fitting surface was measured from the reference plane on the fitting side from which a coordinate system was set, and the movement of the artificial teeth and the distortion of the polished surface was measured from the reference plane of the artificial tooth side, from which a coordinate system was set. It was clearly showed that various distortions of denture specimens after polymerization process can be measured with this three-coordinate measuring machine. The study showed that the overall distortion of the fitting surface in HP specimens was shown to be larger than in MP ones.

  18. Poly(N-isopropylacrylamide) hydrogel/chitosan scaffold hybrid for three-dimensional stem cell culture and cartilage tissue engineering.

    Science.gov (United States)

    Mellati, Amir; Kiamahalleh, Meisam Valizadeh; Madani, S Hadi; Dai, Sheng; Bi, Jingxiu; Jin, Bo; Zhang, Hu

    2016-11-01

    Providing a controllable and definable three-dimensional (3D) microenvironment for chondrogenic differentiation of mesenchymal stem cells (MSCs) remains a great challenge for cartilage tissue engineering. In this work, poly(N-isopropylacrylamide) (PNIPAAm) polymers with the degrees of polymerization of 100 and 400 (NI100 and NI400) were prepared and the polymer solutions were introduced into the preprepared chitosan porous scaffolds (CS) to form hybrids (CSNI100 and CSNI400, respectively). SEM images indicated that the PNIPAAm gel partially occupied chitosan pores while the interconnected porous structure of chitosan was preserved. MSCs were incorporated within the hybrid and cell proliferation and chondrogenic differentiation were monitored. After 7-day incubation of the cell-laden constructs in a growth medium, the cell viability in CSNI100 and CSNI400 were 54 and 108% higher than that in CS alone, respectively. Glycosaminoglycan and total collagen contents increased 2.6- and 2.5-fold after 28-day culture of cell-laden CSNI400 in the chondrogenic medium. These results suggest that the hybrid structure composed of the chitosan porous scaffold and the well-defined PNIPAAm hydrogel, in particular CSNI400, is suitable for 3D stem cell culture and cartilage tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2764-2774, 2016. © 2016 Wiley Periodicals, Inc.

  19. Coating of hydrophobins on three-dimensional electrospun poly(lactic-co-glycolic acid) scaffolds for cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Hou Sen; Li Xinxin; Li Xiaoyu; Feng Xizeng, E-mail: xzfeng@nankai.edu.c [College of Life Science, Nankai University, Weijin Road 94, Tianjin, 300071 (China)

    2009-09-15

    Surface modification with hydrophobins is very important for cell adhesion in its applications in biosensor fabrication. In this study, we modified the surface of three-dimensional electrospun poly(lactide-co-glycolide) (PLGA) scaffolds with hydrophobin HFBI and collagen, and investigated its applications for cell adhesion. We found that HFBI could not only improve the hydrophilicity of the three-dimensional electrospun PLGA scaffolds but also endow the electrospun PLGA scaffolds with water permeability. This permeability should be attributed to both the hydrophilicity of the modified PLGA surface and the large positive capillary effect induced by the microstructures. Further experiment indicated that HFBI modification could improve collagen immobilization on the electrospun PLGA scaffolds and the HFBI/collagen modified electrospun PLGA scaffolds showed higher efficiency in promoting cell adhesion than the native PLGA scaffolds. This finding should be of potential application in biosensor device fabrication.

  20. Extrusion-based, three-dimensional printing of calcium-phosphate scaffolds

    Science.gov (United States)

    Witek, Lukasz

    Small or large bone defects, can occur due to a variety of reasons: congenital disorders, infections, tumors, or traumas which can lead to significant disabilities. There is an assortment of bone grafting procedures, each having their own respective advantages and disadvantages and exhibiting certain essential characteristics. Among the available grafts, autogenous (autograft), allograft, xenograft, and alloplasts, all exhibit a minimum of two-thirds of the essential characteristics and have been proven useful in fully or partially repairing skeletal defects. However, different host-to-grafting material responses have been reported and should be taken into consideration when determining treatment options. A large range of physical and chemical properties can be achieved with calcium phosphate based materials, which possess two of the ideal characteristics for grafting procedures: osteoconduction and osseointegration. Calcium phosphate based scaffolds composed of hydroxyapatite (HA), beta-tri-calcium phosphate (beta-TCP), or a combination of both (HA/beta-TCP) were investigated as materials for three-dimensional printing process to create layer-by-layer structures for use as bone regeneration scaffolds. Different calcium-phosphate phases will result in different degrees of in vivo dissolution and/or cell-mediated resorption. There has been a growing interest in BCP because it has been shown that this material improves the formation of new bone inside the implanted scaffold. The literature indicates that the faster dissolution rate of ?-TCP would be greatly responsible of this enhancement. However, in vitro tests indicate that fast dissolution can decrease the mechanical strength of BCP scaffolds. Furthermore, studies reported that HA has higher mechanical strength and lower degradation rate than beta-TCP. Therefore, the HA/beta-TCP ratio is a key parameter controlling the performance of the scaffold for bone repair applications, since it determines degradation rate

  1. Whole-organ tissue engineering: decellularization and recellularization of three-dimensional matrix liver scaffolds.

    Science.gov (United States)

    Sabetkish, Shabnam; Kajbafzadeh, Abdol-Mohammad; Sabetkish, Nastaran; Khorramirouz, Reza; Akbarzadeh, Aram; Seyedian, Sanam Ladi; Pasalar, Parvin; Orangian, Saghar; Beigi, Reza Seyyed Hossein; Aryan, Zahra; Akbari, Hesam; Tavangar, Seyyed Mohammad

    2015-04-01

    To report the results of whole liver decellularization by two different methods. To present the results of grafting rat and sheep decellularized liver matrix (DLM) into the normal rat liver and compare natural cell seeding process in homo/xenograft of DLM. To compare the results of in vitro whole liver recellularization with rats' neonatal green fluorescent protein (GFP)-positive hepatic cells with outcomes of in vivo recellularization process. Whole liver of 8 rats and 4 sheep were resected and cannulated via the hepatic vein and perfused with sodium dodecyl sulfate (SDS) or Triton + SDS. Several examinations were performed to compare the efficacy of these two decellularization procedures. In vivo recellularization of sheep and rat DLMs was performed following transplantation of multiple pieces of both scaffolds in the subhepatic area of four rats. To compare the efficacy of different scaffolds in autologous cell seeding, biopsies of homograft and xenograft were assessed 8 weeks postoperatively. Whole DLMs of 4 rats were also recellularized in vitro by perfusion of rat's fetal GFP-positive hepatic cells with pulsatile bioreactor. Histological evaluation and enzymatic assay were performed for both in vivo and in vitro recellularized samples. The results of this study demonstrated that the triton method was a promising decellularization approach for preserving the three-dimensional structure of liver. In vitro recellularized DLMs were more similar to natural ones compared with in vivo recellularized livers. However, homografts showed better characteristics with more organized structure compared with xenografts. In vitro recellularization of liver scaffolds with autologous cells represents an attractive prospective for regeneration of liver as one of the most compound organs. In vivo cell seeding on the scaffold of the same species may have more satisfactory outcomes when compared with the results of xenotransplantation. This study theoretically may pave the road for

  2. Three-dimensional cell manipulation and patterning using dielectrophoresis via a multi-layer scaffold structure.

    Science.gov (United States)

    Chu, H K; Huan, Z; Mills, J K; Yang, J; Sun, D

    2015-02-07

    Cell manipulation is imperative to the areas of cellular biology and tissue engineering, providing them a useful tool for patterning cells into cellular patterns for different analyses and applications. This paper presents a novel approach to perform three-dimensional (3D) cell manipulation and patterning with a multi-layer engineered scaffold. This scaffold structure employed dielectrophoresis as the non-contact mechanism to manipulate cells in the 3D domain. Through establishing electric fields via this multi-layer structure, the cells in the medium became polarized and were attracted towards the interior part of the structure, forming 3D cellular patterns. Experiments were conducted to evaluate the manipulation and the patterning processes with the proposed structure. Results show that with the presence of a voltage input, this multi-layer structure was capable of manipulating different types of biological cells examined through dielectrophoresis, enabling automatic cell patterning in the time-scale of minutes. The effects of the voltage input on the resultant cellular pattern were examined and discussed. Viability test was performed after the patterning operation and the results confirmed that majority of the cells remained viable. After 7 days of culture, 3D cellular patterns were observed through SEM. The results suggest that this scaffold and its automated dielectrophoresis-based patterning mechanism can be used to construct artificial tissues for various tissue engineering applications.

  3. Strontium-doped organic-inorganic hybrids towards three-dimensional scaffolds for osteogenic cells

    Energy Technology Data Exchange (ETDEWEB)

    John, Łukasz, E-mail: lukasz.john@chem.uni.wroc.pl [Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław (Poland); Podgórska, Marta [Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław (Poland); Nedelec, Jean-Marie [Université Clermont Auvergne, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63178 Aubiere (France); Cwynar-Zając, Łucja [Department of Histology and Embryology, Wrocław Medical University, 6a Chałubińskiego, 50-368 Wrocław (Poland); Dzięgiel, Piotr [Department of Histology and Embryology, Wrocław Medical University, 6a Chałubińskiego, 50-368 Wrocław (Poland); Department of Physiotherapy and Occupational Therapy in Conservative and Interventional Medicine, 35 Paderewskiego, 51-612 Wrocław (Poland)

    2016-11-01

    Biomimetic organic–inorganic hybrid bioscaffolds are developed to complement or replace damaged fragments in bone tissue surgery. The aim of this work was to develop a simple and fast method to prepare composite material for bone engineering, avoiding time consuming and complex methodologies. The resulting materials (also called in this work as hybrid composites or hybrid scaffolds) have a three-dimensional macroporous polymer-like network derived from triethoxyvinylsilane (TEVS) and 2-hydroxyethylmethacrylate (HEMA) monomers, with incorporated calcium, strontium, and phosphate ions. The materials were fully characterized using FT-IR, biomineralization studies, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, scratch tests, Young's modulus and compressive strength tests, and gas physisorption. We report a comprehensive study on the in vitro effect of novel strontium doped materials on human bone cells. In vitro investigations were conducted using a normal human osteoblast cell line that mimics the cellular events of the in vivo intramembranous bone formation process. The materials do not have a negative impact on the survival of the normal human osteoblasts; moreover, materials doped with strontium show that not only are cells able to survive, but they also attach to and grow on a bioscaffolds surface. For this reason, they may be used in future in vivo experiments. - Highlights: • New hybrid scaffolds derived from TEVS and HEMA doped with Ca{sup 2+}, Sr{sup 2+}, and PO{sub 4}{sup 3-} ions have been developed. • A comprehensive characterization of the scaffolds for regenerative medicine was performed. • The incorporation of Sr{sup 2+} ions into the scaffolds was non-cytotoxic to the osteoblasts.

  4. Design and characterization of microcapsules-integrated collagen matrixes as multifunctional three-dimensional scaffolds for soft tissue engineering.

    Science.gov (United States)

    Del Mercato, Loretta L; Passione, Laura Gioia; Izzo, Daniela; Rinaldi, Rosaria; Sannino, Alessandro; Gervaso, Francesca

    2016-09-01

    Three-dimensional (3D) porous scaffolds based on collagen are promising candidates for soft tissue engineering applications. The addition of stimuli-responsive carriers (nano- and microparticles) in the current approaches to tissue reconstruction and repair brings about novel challenges in the design and conception of carrier-integrated polymer scaffolds. In this study, a facile method was developed to functionalize 3D collagen porous scaffolds with biodegradable multilayer microcapsules. The effects of the capsule charge as well as the influence of the functionalization methods on the binding efficiency to the scaffolds were studied. It was found that the binding of cationic microcapsules was higher than that of anionic ones, and application of vacuum during scaffolds functionalization significantly hindered the attachment of the microcapsules to the collagen matrix. The physical properties of microcapsules-integrated scaffolds were compared to pristine scaffolds. The modified scaffolds showed swelling ratios, weight losses and mechanical properties similar to those of unmodified scaffolds. Finally, in vitro diffusional tests proved that the collagen scaffolds could stably retain the microcapsules over long incubation time in Tris-HCl buffer at 37°C without undergoing morphological changes, thus confirming their suitability for tissue engineering applications. The obtained results indicate that by tuning the charge of the microcapsules and by varying the fabrication conditions, collagen scaffolds patterned with high or low number of microcapsules can be obtained, and that the microcapsules-integrated scaffolds fully retain their original physical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Towards Tuning the Mechanical Properties of Three-Dimensional Collagen Scaffolds Using a Coupled Fiber-Matrix Model

    Directory of Open Access Journals (Sweden)

    Shengmao Lin

    2015-08-01

    Full Text Available Scaffold mechanical properties are essential in regulating the microenvironment of three-dimensional cell culture. A coupled fiber-matrix numerical model was developed in this work for predicting the mechanical response of collagen scaffolds subjected to various levels of non-enzymatic glycation and collagen concentrations. The scaffold was simulated by a Voronoi network embedded in a matrix. The computational model was validated using published experimental data. Results indicate that both non-enzymatic glycation-induced matrix stiffening and fiber network density, as regulated by collagen concentration, influence scaffold behavior. The heterogeneous stress patterns of the scaffold were induced by the interfacial mechanics between the collagen fiber network and the matrix. The knowledge obtained in this work could help to fine-tune the mechanical properties of collagen scaffolds for improved tissue regeneration applications.

  6. Three-dimensional plotted hydroxyapatite scaffolds with predefined architecture: comparison of stabilization by alginate cross-linking versus sintering.

    Science.gov (United States)

    Kumar, Alok; Akkineni, Ashwini R; Basu, Bikramjit; Gelinsky, Michael

    2016-03-01

    Scaffolds for bone tissue engineering are essentially characterized by porous three-dimensional structures with interconnected pores to facilitate the exchange of nutrients and removal of waste products from cells, thereby promoting cell proliferation in such engineered scaffolds. Although hydroxyapatite is widely being considered for bone tissue engineering applications due to its occurrence in the natural extracellular matrix of this tissue, limited reports are available on additive manufacturing of hydroxyapatite-based materials. In this perspective, hydroxyapatite-based three-dimensional porous scaffolds with two different binders (maltodextrin and sodium alginate) were fabricated using the extrusion method of three-dimensional plotting and the results were compared in reference to the structural properties of scaffolds processed via chemical stabilization and sintering routes, respectively. With the optimal processing conditions regarding to pH and viscosity of binder-loaded hydroxyapatite pastes, scaffolds with parallelepiped porous architecture having up to 74% porosity were fabricated. Interestingly, sintering of the as-plotted hydroxyapatite-sodium alginate (cross-linked with CaCl2 solution) scaffolds led to the formation of chlorapatite (Ca9.54P5.98O23.8Cl1.60(OH)2.74). Both the sintered scaffolds displayed progressive deformation and delayed fracture under compressive loading, with hydroxyapatite-alginate scaffolds exhibiting a higher compressive strength (9.5 ± 0.5 MPa) than hydroxyapatite-maltodextrin scaffolds (7.0 ± 0.6 MPa). The difference in properties is explained in terms of the phase assemblage and microstructure. © The Author(s) 2015.

  7. Strong and biocompatible three-dimensional porous silk fibroin/graphene oxide scaffold prepared by phase separation.

    Science.gov (United States)

    Wang, Shu-Dong; Ma, Qian; Wang, Ke; Ma, Pi-Bo

    2018-05-01

    Silk fibroin (SF) is blended with graphene oxide (GO) to prepare the strong and biocompatible three dimensional porous SF/GO blended scaffold via phase separation. GO could be well dispersed in SF solution and GO could also be well distributed in the SF scaffold. Furthermore, the introduction of GO can lead to structural change in the bended scaffold. Higher concentration of GO resulted in more compact structure and smaller pore size of the composite scaffolds without decreasing their porosity. Scanning electron microscopy and energy dispersive spectrometry results also reveal that SF and GO are homogeneous blended together. Analysis of chemical structures of the scaffold shows that addition of GO do not affect the crystalline structure of SF and it is evenly blended with SF. The blended scaffold has significantly higher breaking strength than the pure SF scaffold. In vitro study indicates that both pure SF scaffold and SF/GO composite scaffold support growth and proliferation of MC3T3-E1 osteoprogenitor cells. However, the addition of GO contribute to the proliferation of MC3T3-E1 osteoprogenitor. The testing results show that the blended scaffold is an appropriate candidate for tissue engineering. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Design of a bioresorbable polymeric scaffold for osteoblast culture

    Science.gov (United States)

    Ditaranto, Vincent M., Jr.

    Bioresorbable polymeric scaffolds were designed for the purpose of growing rat osteosarcoma cells (ROS 17/2.8) using the compression molding method. The material used in the construction of the scaffolds was a mixture of polycaprolactone (PCL), Hydroxyapatite (HA), Glycerin (GL) and salt (NaCl) for porosity. The concentration of the several materials utilized, was determined by volume. Past research at the University of Massachusetts Lowell (UML) has successfully utilized the compression molding method for the construction of scaffolds, but was unable to accomplish the goal of long term cell survival and complete cellular proliferation throughout a three dimensional scaffold. This research investigated various concentrations of the materials and molding temperatures used for the manufacture of scaffolds in order to improve the scaffold design and address those issues. The design of the scaffold using the compression molding process is detailed in the Method and Materials section of this thesis. The porogen (salt) used for porosity was suspected as a possible source of contamination causing cell apoptosis in past studies. This research addressed the issues for cell survival and proliferation throughout a three dimensional scaffold. The leaching of the salt was one major design modification. This research successfully used ultrasonic leaching in addition to the passive method. Prior to cell culture, the scaffolds were irradiated to 2.75 Mrad, with cobalt-60 gamma radionuclide. The tissue culture consisted of two trials: (1) cell culture in scaffolds cleaned with passive leaching; (2) cell culture with scaffolds cleaned with ultrasonic leaching. Cell survival and proliferation was accomplished only with the addition of ultrasonic leaching of the scaffolds. Analysis of the scaffolds included Scanning Electron Microscopy (SEM), Nikon light microscopy and x-ray mapping of the calcium, sodium and chloride ion distribution. The cells were analyzed by Environmental Scanning

  9. Preparation and characterization of a three-dimensional printed scaffold based on a functionalized polyester for bone tissue engineering applications.

    Science.gov (United States)

    Seyednejad, Hajar; Gawlitta, Debby; Dhert, Wouter J A; van Nostrum, Cornelus F; Vermonden, Tina; Hennink, Wim E

    2011-05-01

    At present there is a strong need for suitable scaffolds that meet the requirements for bone tissue engineering applications. The objective of this study was to investigate the suitability of porous scaffolds based on a hydroxyl functionalized polymer, poly(hydroxymethylglycolide-co-ε-caprolactone) (pHMGCL), for tissue engineering. In a recent study this polymer was shown to be a promising material for bone regeneration. The scaffolds consisting of pHMGCL or poly(ε-caprolactone) (PCL) were produced by means of a rapid prototyping technique (three-dimensional plotting) and were shown to have a high porosity and an interconnected pore structure. The thermal and mechanical properties of both scaffolds were investigated and human mesenchymal stem cells were seeded onto the scaffolds to evaluate the cell attachment properties, as well as cell viability and differentiation. It was shown that the cells filled the pores of the pHMGCL scaffold within 7 days and displayed increased metabolic activity when compared with cells cultured in PCL scaffolds. Importantly, pHMGCL scaffolds supported osteogenic differentiation. Therefore, scaffolds based on pHMGCL are promising templates for bone tissue engineering applications. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Two-Photon Polymerization lithography for three-dimensional micro polymer parts manufacturing evaluation

    DEFF Research Database (Denmark)

    Davoudinejad, Ali; Malureanu, Radu; Palima, Darwin

    2017-01-01

    Two-photon polymerization (2PP) technique is one of the common techniques to realize the fabrication of high-quality 3D microstructures. The combination between the laser power, the printing strategy, and the printed feature size are not completely assessed. This study characterizes the additive...... manufacturing processes by Direct Laser Writing (DLW) for fabrication of 3D microstructures. The printing samples were selected from a certified calibrated set with different sizes consisting of five boxes ranging from 8 μm to 200 μm. The laser power was selected as a variable parameter in order to find out...... for too low one. In addition, they show the importance of a good scaffolding, especially for bigger structures where the geometry can be distorted....

  11. Effect of hydroxyapatite-containing microspheres embedded into three-dimensional magnesium phosphate scaffolds on the controlled release of lysozyme and in vitro biodegradation

    Directory of Open Access Journals (Sweden)

    Lee JM

    2014-09-01

    Full Text Available Jongman Lee, Hui-suk YunPowder and Ceramics Division, Korea Institute of Materials Science, Changwon, Republic of KoreaAbstract: The functionality of porous three-dimensional (3D magnesium phosphate (MgP scaffold was investigated for the development of a novel protein delivery system and biomimetic bone tissue engineering scaffold. This enhancement can be achieved by incorporation of hydroxyapatite (HA-containing polymeric microspheres (MSs into a bulk MgP matrix, and a paste-extruding deposition (PED system. In this work, the amount of MS and HA was precisely controlled when manufacturing MS-embedded MgP (MS/MgP composite scaffolds. The main influence was researched in terms of in vitro lysozyme-release, in vitro biodegradation, mechanical properties, and in vitro calcification. The controlled release of lysozyme was indicated, while showing graded release patterns according to HA content. The composite scaffolds degraded gradually with MS content and degradation time. Due to the effect of HA inclusion, the higher HA-containing MS/MgP scaffolds could, not only delay the biodegradation process but also, compensate for the possible loss of mechanical properties. In this regard, it is reasonable to confirm the inverse relationship between biodegradation and corresponding compressive properties. In order to encourage bioactivity and osteoconductivity, the MS/MgP composite scaffolds were subjected to simulated body fluid treatment. Calcium deposition was, in turn, improved with increasing MS and HA content over time. This quantitative result was also proved using morphological and elemental analysis. In summary, a significant transformation of a monolithic MgP scaffold was directed toward a multifunctional bone tissue engineering scaffold equipped with controlled protein delivery, biodegradability, and bioactivity.Keywords: protein delivery, bone tissue engineering

  12. Bioactive polymeric scaffolds for tissue engineering

    Directory of Open Access Journals (Sweden)

    Scott Stratton

    2016-12-01

    Full Text Available A variety of engineered scaffolds have been created for tissue engineering using polymers, ceramics and their composites. Biomimicry has been adopted for majority of the three-dimensional (3D scaffold design both in terms of physicochemical properties, as well as bioactivity for superior tissue regeneration. Scaffolds fabricated via salt leaching, particle sintering, hydrogels and lithography have been successful in promoting cell growth in vitro and tissue regeneration in vivo. Scaffold systems derived from decellularization of whole organs or tissues has been popular due to their assured biocompatibility and bioactivity. Traditional scaffold fabrication techniques often failed to create intricate structures with greater resolution, not reproducible and involved multiple steps. The 3D printing technology overcome several limitations of the traditional techniques and made it easier to adopt several thermoplastics and hydrogels to create micro-nanostructured scaffolds and devices for tissue engineering and drug delivery. This review highlights scaffold fabrication methodologies with a focus on optimizing scaffold performance through the matrix pores, bioactivity and degradation rate to enable tissue regeneration. Review highlights few examples of bioactive scaffold mediated nerve, muscle, tendon/ligament and bone regeneration. Regardless of the efforts required for optimization, a shift in 3D scaffold uses from the laboratory into everyday life is expected in the near future as some of the methods discussed in this review become more streamlined.

  13. Three dimensional printing of calcium sulfate and mesoporous bioactive glass scaffolds for improving bone regeneration in vitro and in vivo

    Science.gov (United States)

    Qi, Xin; Pei, Peng; Zhu, Min; Du, Xiaoyu; Xin, Chen; Zhao, Shichang; Li, Xiaolin; Zhu, Yufang

    2017-02-01

    In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the effect of CSH/MBG scaffolds on bone regeneration in vivo. The in vitro results showed that CSH/MBG scaffolds stimulated the adhesion, proliferation, alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of hBMSCs. In vivo results showed that CSH/MBG scaffolds could significantly enhance new bone formation in calvarial defects compared to CSH scaffolds. Thus 3D printed CSH/MBG scaffolds would be promising candidates for promoting bone regeneration.

  14. Image-Based Three-Dimensional Analysis to Characterize the Texture of Porous Scaffolds

    Directory of Open Access Journals (Sweden)

    Diana Massai

    2014-01-01

    Full Text Available The aim of the present study is to characterize the microstructure of composite scaffolds for bone tissue regeneration containing different ratios of chitosan/gelatin blend and bioactive glasses. Starting from realistic 3D models of the scaffolds reconstructed from micro-CT images, the level of heterogeneity of scaffold architecture is evaluated performing a lacunarity analysis. The results demonstrate that the presence of the bioactive glass component affects not only macroscopic features such as porosity, but mainly scaffold microarchitecture giving rise to structural heterogeneity, which could have an impact on the local cell-scaffold interaction and scaffold performances. The adopted approach allows to investigate the scale-dependent pore distribution within the scaffold and the related structural heterogeneity features, providing a comprehensive characterization of the scaffold texture.

  15. Oxygen and nitrogen plasma etching of three-dimensional hydroxyapatite/chitosan scaffolds fabricated by additive manufacturing

    Science.gov (United States)

    Myung, Sung-Woon; Kim, Byung-Hoon

    2016-01-01

    Three-dimensional (3D) chitosan and hydroxyapatite (HAp)/chitosan (CH) scaffolds were fabricated by additive manufacturing, then their surfaces were etched with oxygen (O2) and nitrogen (N2) plasma. O2 and N2 plasma etching was performed to increase surface properties such as hydrophilicity, roughness, and surface chemistry on the scaffolds. After etching, hydroxyapatite was exposed on the surface of 3D HAp/CH scaffolds. The surface morphology and chemical properties were characterized by contact angle measurement, scanning electron microscopy, X-ray diffraction, and attenuated total reflection Fourier infrared spectroscopy. The cell viability of 3D chitosan scaffolds was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The differentiation of preosteoblast cells was evaluated by alkaline phosphatase assay. The cell viability was improved by O2 and N2 plasma etching of 3D chitosan scaffolds. The present fabrication process for 3D scaffolds might be applied to a potential tool for preparing biocompatible scaffolds.

  16. Membrane-reinforced three-dimensional electrospun silk fibroin scaffolds for bone tissue engineering

    International Nuclear Information System (INIS)

    Yang, Sung Yeun; Hwang, Tae Heon; Ryu, WonHyoung; Che, Lihua; Oh, Jin Soo; Ha, Yoon

    2015-01-01

    Electrospun silk fibroin (SF) scaffolds have drawn much attention because of their resemblance to natural tissue architecture such as extracellular matrix, and the biocompatibility of SF as a candidate material to replace collagen. However, electrospun scaffolds lack the physical integrity of bone tissue scaffolds, which require resistance to mechanical loadings. In this work, we propose membrane-reinforced electrospun SF scaffolds by a serial process of electrospinning and freeze-drying of SF solutions in two different solvents: formic acid and water, respectively. After wet electrospinning followed by replacement of methanol with water, SF nanofibers dispersed in water were mixed with aqueous SF solution. Freeze-drying of the mixed solution resulted in 3D membrane-connected SF nanofibrous scaffolds (SF scaffolds) with a thickness of a few centimeters. We demonstrated that the SF concentration of aqueous SF solution controlled the degree of membrane reinforcement between nanofibers. It was also shown that both increase in degree of membrane reinforcement and inclusion of hydroxyapatite (HAP) nanoparticles resulted in higher resistance to compressive loadings of the SF scaffolds. Culture of human osteoblasts on collagen, SF, and SF-HAP scaffolds showed that both SF and SF-HAP scaffolds had biocompatibility and cell proliferation superior to that of the collagen scaffolds. SF-HAP scaffolds with and without BMP-2 were used for in vivo studies for 4 and 8 weeks, and they showed enhanced bone tissue formation in rat calvarial defect models. (paper)

  17. Characterization of Three-Dimensional Printed Composite Scaffolds Prepared with Different Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Szlązak K.

    2016-06-01

    Full Text Available An optimal method for composites preparation as an input to rapid prototyping fabrication of scaffolds with potential application in osteochondral tissue engineering is still needed. Scaffolds in tissue engineering applications play a role of constructs providing appropriate mechanical support with defined porosity to assist regeneration of tissue. The aim of the presented study was to analyze the influence of composite fabrication methods on scaffolds mechanical properties. The evaluation was performed on polycaprolactone (PCL with 5 wt% beta-tricalcium phosphate (TCP scaffolds fabricated using fused deposition modeling (FDM. Three different methods of PCL-TCP composite preparation: solution casting, particles milling, extrusion and injection were used to provide material for scaffold fabrication. The obtained scaffolds were investigated by means of scanning electron microscope, x-ray micro computed tomography, thermal gravimetric analysis and static material testing machine. All of the scaffolds had the same geometry (cylinder, 4×6 mm and fiber orientation (0/60/120°. There were some differences in the TCP distribution and formation of the ceramic agglomerates in the scaffolds. They depended on fabrication method. The use of composites prepared by solution casting method resulted in scaffolds with the best combination of compressive strength (5.7±0.2 MPa and porosity (48.5±2.7 %, both within the range of trabecular bone.

  18. Three-dimensional CaP/gelatin lattice scaffolds with integrated osteoinductive surface topographies for bone tissue engineering

    International Nuclear Information System (INIS)

    Nadeem, Danish; Su, Bo; Smith, Carol-Anne; Dalby, Matthew J; Dominic Meek, R M; Lin, Sien; Li, Gang

    2015-01-01

    Surface topography is known to influence stem cells and has been widely used as physical stimuli to modulate cellular behaviour including adhesion, proliferation and differentiation on 2D surfaces. Integration of well-defined surface topography into three-dimensional (3D) scaffolds for tissue engineering would be useful to direct the cell fate for intended applications. Technical challenges are remaining as how to fabricate such 3D scaffolds with controlled surface topography from a range of biodegradable and biocompatible materials. In this paper, a novel fabrication process using computer numerically controlled machining and lamination is reported to make 3D calcium phosphate/gelatin composite scaffolds with integrated surface micropatterns that are introduced by embossing prior to machining. Geometric analysis shows that this method is versatile and can be used to make a wide range of lattices with porosities that meet the basic requirements for bone tissue engineering. Both in vitro and in vivo studies show that micropatterned composite scaffolds with surfaces comprising 40 μm pits and 50 μm grooves were optimal for improved osteogenesis. The results have demonstrated the potential of a novel fabrication process for producing cell-instructive scaffolds with designed surface topographies to induce specific tissue regeneration. (paper)

  19. Tumor cell culture on collagen–chitosan scaffolds as three-dimensional tumor model: A suitable model for tumor studies

    Directory of Open Access Journals (Sweden)

    Aziz Mahmoudzadeh

    2016-07-01

    Full Text Available Tumor cells naturally live in three-dimensional (3D microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen–chitosan scaffold compared with 2D plate cultures. Collagen–chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen–chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies.

  20. Tumor cell culture on collagen-chitosan scaffolds as three-dimensional tumor model: A suitable model for tumor studies.

    Science.gov (United States)

    Mahmoudzadeh, Aziz; Mohammadpour, Hemn

    2016-07-01

    Tumor cells naturally live in three-dimensional (3D) microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D) plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen-chitosan scaffold compared with 2D plate cultures. Collagen-chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen-chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies. Copyright © 2016. Published by Elsevier B.V.

  1. Fibrin promotes proliferation and matrix production of intervertebral disc cells cultured in three-dimensional poly(lactic-co-glycolic acid) scaffold.

    Science.gov (United States)

    Sha'ban, Munirah; Yoon, Sun Jung; Ko, Youn Kyung; Ha, Hyun Jung; Kim, Soon Hee; So, Jung Won; Idrus, Ruszymah Bt Hj; Khang, Gilson

    2008-01-01

    Previously, we have proven that fibrin and poly(lactic-co-glycolic acid) (PLGA) scaffolds facilitate cell proliferation, matrix production and early chondrogenesis of rabbit articular chondrocytes in in vitro and in vivo experiments. In this study, we evaluated the potential of fibrin/PLGA scaffold for intervertebral disc (IVD) tissue engineering using annulus fibrosus (AF) and nucleus pulposus (NP) cells in relation to potential clinical application. PLGA scaffolds were soaked in cells-fibrin suspension and polymerized by dropping thrombin-sodium chloride (CaCl(2)) solution. A PLGA-cell complex without fibrin was used as control. Higher cellular proliferation activity was observed in fibrin/PLGA-seeded AF and NP cells at each time point of 3, 7, 14 and 7 days using the MTT assay. After 3 weeks in vitro incubation, fibrin/PLGA exhibited a firmer gross morphology than PLGA groups. A significant cartilaginous tissue formation was observed in fibrin/PLGA, as proven by the development of cells cluster of various sizes and three-dimensional (3D) cartilaginous histoarchitecture and the presence of proteoglycan-rich matrix and glycosaminoglycan (GAG). The sGAG production measured by 1,9-dimethylmethylene blue (DMMB) assay revealed greater sGAG production in fibrin/PLGA than PLGA group. Immunohistochemical analyses showed expressions of collagen type II, aggrecan core protein and collagen type I genes throughout in vitro culture in both fibrin/PLGA and PLGA. In conclusion, fibrin promotes cell proliferation, stable in vitro tissue morphology, superior cartilaginous tissue formation and sGAG production of AF and NP cells cultured in PLGA scaffold. The 3D porous PLGA scaffold-cell complexes using fibrin can provide a vehicle for delivery of cells to regenerate tissue-engineered IVD tissue.

  2. Porous alumina scaffold produced by sol-gel combined polymeric sponge method

    Science.gov (United States)

    Hasmaliza, M.; Fazliah, M. N.; Shafinaz, R. J.

    2012-09-01

    Sol gel is a novel method used to produce high purity alumina with nanometric scale. In this study, three-dimensional porous alumina scaffold was produced using sol-gel polymeric sponge method. Briefly, sol gel alumina was prepared by evaporation and polymeric sponge cut to designated sizes were immersed in the sol gel followed by sintering at 1250 and 1550°C. In order to study the cell interaction, the porous alumina scaffold was sterilized using autoclave prior to Human Mesenchymal Stem Cells (HMSCs) seeding on the scaffold and the cell proliferation was assessed by alamarBlue® assay. SEM results showed that during the 21 day period, HMSCs were able to attach on the scaffold surface and the interconnecting pores while maintaining its proliferation. These findings suggested the potential use of the porous alumina produced as a scaffold for implantation procedure.

  3. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

    2016-09-02

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  4. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    International Nuclear Information System (INIS)

    Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

    2016-01-01

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  5. Three-dimensional electrospun polycaprolactone (PCL)/alginate hybrid composite scaffolds.

    Science.gov (United States)

    Kim, Min Seong; Kim, GeunHyung

    2014-12-19

    Micro/nanofibrous scaffolds have been used widely in biomedical applications because the micro/nano-scale fibres resemble natural extracellular matrix and the high surface-to-volume ratio encourages cellular activities (attachment and proliferation). However, poor mechanical properties, low controllability of various shapes and difficulties in obtaining controllable pore structure have been obstacles to their use in hard-tissue regeneration. To overcome these shortcomings, we suggest a new composite system, which uses a combination method of wet electrospinning, rapid prototyping and a physical punching process. Using the process, we obtained polycaprolactone (PCL)/alginate composite scaffolds, consisting of electrospun PCL/alginate fibres and micro-sized PCL struts, with mean pore sizes of 821 ± 55 μm. To show the feasibility of the scaffolds for hard-tissue regeneration, the scaffolds were assessed not only for physical properties, including hydrophilicity, water absorption, and tensile and compressive strength, but also in vitro cellular responses (cell viability and proliferation) and osteogenic differentiation (alkaline phosphatase (ALP) activity, and mineralisation) by culturing with pre-osteoblasts (MC3T3-E1 cells). With the reinforcing micro-sized PCL struts, the elastic modulus of the PCL/alginate scaffold was significantly improved versus a pure PCL scaffold. Additionally, due to the alginate component in the fibrous scaffold, they showed significantly enhanced hydrophilic behaviour, water absorption (∼8-fold) and significant biological activities (∼1.6-fold for cell viability at 7 days, ∼2.3-fold for ALP activity at 14 days and ∼6.4-fold for calcium mineralisation at 14 days) compared with those of a pure PCL fibrous scaffold. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Laser sintering fabrication of three-dimensional tissue engineering scaffolds with a flow channel network.

    Science.gov (United States)

    Niino, T; Hamajima, D; Montagne, K; Oizumi, S; Naruke, H; Huang, H; Sakai, Y; Kinoshita, H; Fujii, T

    2011-09-01

    The fabrication of tissue engineering scaffolds for the reconstruction of highly oxygen-dependent inner organs is discussed. An additive manufacturing technology known as selective laser sintering was employed to fabricate a highly porous scaffold with an embedded flow channel network. A porogen leaching system was used to obtain high porosity. A prototype was developed using the biodegradable plastic polycaprolactone and sodium chloride as the porogen. A high porosity of 90% was successfully obtained. Micro x-ray CT observation was carried out to confirm that channels with a diameter of approximately 1 mm were generated without clogging. The amount of residual salt was 930 µg while the overall volume of the scaffold was 13 cm(3), and it was confirmed that the toxicity of the salt was negligible. The hydrophilization of the scaffold to improve cell adhesion on the scaffold is also discussed. Oxygen plasma ashing and hydrolysis with sodium hydroxide, typically employed to improve the hydrophilicity of plastic surfaces, were tested. The improvement of hydrophilicity was confirmed by an increase in water retention by the porous scaffold from 180% to 500%.

  7. Macro- and micro-designed chitosan-alginate scaffold architecture by three-dimensional printing and directional freezing

    International Nuclear Information System (INIS)

    Reed, Stephanie; Wu, Benjamin M; Lau, Grace; Delattre, Benjamin; Lopez, David Don; Tomsia, Antoni P

    2016-01-01

    While many tissue-engineered constructs aim to treat cartilage defects, most involve chondrocyte or stem cell seeding on scaffolds. The clinical application of cell-based techniques is limited due to the cost of maintaining cellular constructs on the shelf, potential immune response to allogeneic cell lines, and autologous chondrocyte sources requiring biopsy from already diseased or injured, scarce tissue. An acellular scaffold that can induce endogenous influx and homogeneous distribution of native stem cells from bone marrow holds great promise for cartilage regeneration. This study aims to develop such an acellular scaffold using designed, channeled architecture that simultaneously models the native zones of articular cartilage and subchondral bone. Highly porous, hydrophilic chitosan-alginate (Ch-Al) scaffolds were fabricated in three-dimensionally printed (3DP) molds designed to create millimeter scale macro-channels. Different polymer preform casting techniques were employed to produce scaffolds from both negative and positive 3DP molds. Macro-channeled scaffolds improved cell suspension distribution and uptake overly randomly porous scaffolds, with a wicking volumetric flow rate of 445.6 ± 30.3 mm 3 s −1 for aqueous solutions and 177 ± 16 mm 3 s −1 for blood. Additionally, directional freezing was applied to Ch-Al scaffolds, resulting in lamellar pores measuring 300 μm and 50 μm on the long and short axes, thus creating micrometer scale micro-channels. After directionally freezing Ch-Al solution cast in 3DP molds, the combined macro- and micro-channeled scaffold architecture enhanced cell suspension uptake beyond either macro- or micro-channels alone, reaching a volumetric flow rate of 1782.1 ± 48 mm 3 s −1 for aqueous solutions and 440.9 ± 0.5 mm 3 s −1 for blood. By combining 3DP and directional freezing, we can control the micro- and macro-architecture of Ch-Al to drastically improve cell influx into and distribution within the

  8. Two-photon polymerization of metal ions doped acrylate monomers and oligomers for three-dimensional structure fabrication

    International Nuclear Information System (INIS)

    Duan Xuanming; Sun Hongbo; Kaneko, Koshiro; Kawata, Satoshi

    2004-01-01

    We have investigated two-photon polymerization of metal ions doped acrylate monomers and oligomers which is applied for three-dimensional (3D) micro/nano-structure fabrication. Titanium (IV) ions doped urethane acrylate photopolymerizable resins were synthesized, and their optical and polymerization properties were investigated. The resolution of two-photon polymerization for micro/nanofabrication was evaluated. Titanium dioxide (TiO 2 ) nanoparticles were generated in the polymer matrix of micron-sized polymer structures. A 3D diamond photonic crystal structure, which consisted of polymer composite materials of TiO 2 nanoparticles, was successfully fabricated by direct laser writing and its photonic bandgap was confirmed. This work would give us a new solution for producing 3D micro/nanodevices of functional polymer composite materials

  9. Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation.

    Science.gov (United States)

    Handschel, Jörg; Naujoks, Christian; Depprich, Rita; Lammers, Lydia; Kübler, Norbert; Meyer, Ulrich; Wiesmann, Hans-Peter

    2011-07-14

    Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs) in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG). After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin. © 2011 Handschel et al; licensee BioMed Central Ltd.

  10. Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation

    Directory of Open Access Journals (Sweden)

    Meyer Ulrich

    2011-07-01

    Full Text Available Abstract Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG. After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin.

  11. The performance of human dental pulp stem cells on different three-dimensional scaffold materials.

    NARCIS (Netherlands)

    Zhang, W.; Walboomers, X.F.; Kuppevelt, A.H.M.S.M. van; Daamen, W.F.; Bian, Z.; Jansen, J.A.

    2006-01-01

    The aim of this study was to investigate the in vitro and in vivo behavior of human dental pulp stem cells (DPSCs) isolated from impacted third molars, when seeded onto different 3-dimensional (3-D) scaffold materials: i.e. a spongeous collagen, a porous ceramic, and a fibrous titanium mesh.

  12. Self-assembly of silk-elastinlike protein polymers into three-dimensional scaffolds for biomedical applications

    Science.gov (United States)

    Zeng, Like

    Production of brand new protein-based materials with precise control over the amino acid sequences at single residue level has been made possible by genetic engineering, through which artificial genes can be developed that encode protein-based materials with desired features. As an example, silk-elastinlike protein polymers (SELPs), composed of tandem repeats of amino acid sequence motifs from Bombyx mori (silkworm) silk and mammalian elastin, have been produced in this approach. SELPs have been studied extensively in the past two decades, however, the fundamental mechanism governing the self-assembly process to date still remains largely unresolved. Further, regardless of the unprecedented success when exploited in areas including drug delivery, gene therapy, and tissue augmentation, SELPs scaffolds as a three-dimensional cell culture model system are complicated by the inability of SELPs to provide the embedded tissue cells with appropriate biochemical stimuli essential for cell survival and function. In this dissertation, it is reported that the self-assembly of silk-elastinlike protein polymers (SELPs) into nanofibers in aqueous solutions can be modulated by tuning the curing temperature, the size of the silk blocks, and the charge of the elastin blocks. A core-sheath model was proposed for nanofiber formation, with the silk blocks in the cores and the hydrated elastin blocks in the sheaths. The folding of the silk blocks into stable cores -- affected by the size of the silk blocks and the charge of the elastin blocks -- plays a critical role in the assembly of silk-elastin nanofibers. The assembled nanofibers further form nanofiber clusters on the microscale, and the nanofiber clusters then coalesce into nanofiber micro-assemblies, interconnection of which eventually leads to the formation of three-dimensional scaffolds with distinct nanoscale and microscale features. SELP-Collagen hybrid scaffolds were also fabricated to enable independent control over the

  13. Application of Synthetic Polymeric Scaffolds in Breast Cancer 3D Tissue Cultures and Animal Tumor Models

    Directory of Open Access Journals (Sweden)

    Girdhari Rijal

    2017-01-01

    Full Text Available Preparation of three-dimensional (3D porous scaffolds from synthetic polymers is a challenge to most laboratories conducting biomedical research. Here, we present a handy and cost-effective method to fabricate polymeric hydrogel and porous scaffolds using poly(lactic-co-glycolic acid (PLGA or polycaprolactone (PCL. Breast cancer cells grown on 3D polymeric scaffolds exhibited distinct survival, morphology, and proliferation compared to those on 2D polymeric surfaces. Mammary epithelial cells cultured on PLGA- or PCL-coated slides expressed extracellular matrix (ECM proteins and their receptors. Estrogen receptor- (ER- positive T47D breast cancer cells are less sensitive to 4-hydroxytamoxifen (4-HT treatment when cultured on the 3D porous scaffolds than in 2D cultures. Finally, cancer cell-laden polymeric scaffolds support consistent tumor formation in animals and biomarker expression as seen in human native tumors. Our data suggest that the porous synthetic polymer scaffolds satisfy the basic requirements for 3D tissue cultures both in vitro and in vivo. The scaffolding technology has appealing potentials to be applied in anticancer drug screening for a better control of the progression of human cancers.

  14. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    International Nuclear Information System (INIS)

    Malinauskas, M.; Purlys, V.; Zukauskas, A.; Rutkauskas, M.; Danilevicius, P.; Paipulas, D.; Bickauskaite, G.; Gadonas, R.; Piskarskas, A.; Bukelskis, L.; Baltriukiene, D.; Bukelskiene, V.; Sirmenis, R.; Gaidukeviciute, A.; Sirvydis, V.

    2010-01-01

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY--ALS130-100, Z--ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software ''3D-Poli'' specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  15. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    Science.gov (United States)

    Malinauskas, M.; Purlys, V.; Žukauskas, A.; Rutkauskas, M.; Danilevičius, P.; Paipulas, D.; Bičkauskaitė, G.; Bukelskis, L.; Baltriukienė, D.; Širmenis, R.; Gaidukevičiutė, A.; Bukelskienė, V.; Gadonas, R.; Sirvydis, V.; Piskarskas, A.

    2010-11-01

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY—ALS130-100, Z—ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software "3D-Poli" specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  16. The self-crosslinking smart hyaluronic acid hydrogels as injectable three-dimensional scaffolds for cells culture.

    Science.gov (United States)

    Bian, Shaoquan; He, Mengmeng; Sui, Junhui; Cai, Hanxu; Sun, Yong; Liang, Jie; Fan, Yujiang; Zhang, Xingdong

    2016-04-01

    Although the disulfide bond crosslinked hyaluronic acid hydrogels have been reported by many research groups, the major researches were focused on effectively forming hydrogels. However, few researchers paid attention to the potential significance of controlling the hydrogel formation and degradation, improving biocompatibility, reducing the toxicity of exogenous and providing convenience to the clinical operations later on. In this research, the novel controllable self-crosslinking smart hydrogels with in-situ gelation property was prepared by a single component, the thiolated hyaluronic acid derivative (HA-SH), and applied as a three-dimensional scaffold to mimic native extracellular matrix (ECM) for the culture of fibroblasts cells (L929) and chondrocytes. A series of HA-SH hydrogels were prepared depending on different degrees of thiol substitution (ranging from 10 to 60%) and molecule weights of HA (0.1, 0.3 and 1.0 MDa). The gelation time, swelling property and smart degradation behavior of HA-SH hydrogel were evaluated. The results showed that the gelation and degradation time of hydrogels could be controlled by adjusting the component of HA-SH polymers. The storage modulus of HA-SH hydrogels obtained by dynamic modulus analysis (DMA) could be up to 44.6 kPa. In addition, HA-SH hydrogels were investigated as a three-dimensional scaffold for the culture of fibroblasts cells (L929) and chondrocytes cells in vitro and as an injectable hydrogel for delivering chondrocytes cells in vivo. These results illustrated that HA-SH hydrogels with controllable gelation process, intelligent degradation behavior, excellent biocompatibility and convenient operational characteristics supplied potential clinical application capacity for tissue engineering and regenerative medicine. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Three-dimensional scaffold-free fusion culture: the way to enhance chondrogenesis of in vitro propagated human articular chondrocytes

    Directory of Open Access Journals (Sweden)

    M. Lehmann

    2013-11-01

    Full Text Available Cartilage regeneration based on isolated and culture-expanded chondrocytes has been studied in various in vitro models, but the quality varies with respect to the morphology and the physiology of the synthesized tissues. The aim of our study was to promote in vitro chondrogenesis of human articular chondrocytes using a novel three-dimensional (3-D cultivation system in combination with the chondrogenic differentiation factors transforming growth factor beta 2 (TGF-b2 and L-ascorbic acid. Articular chondrocytes isolated from six elderly patients were expanded in monolayer culture. A single-cell suspension of the dedifferentiated chondrocytes was then added to agar-coated dishes without using any scaffold material, in the presence, or absence of TGF-b2 and/or L-ascorbic acid. Three-dimensional cartilage-like constructs, called single spheroids, and microtissues consisting of several spheroids fused together, named as fusions, were formed. Generated tissues were mainly characterized using histological and immunohistochemical techniques. The morphology of the in vitro tissues shared some similarities to native hyaline cartilage in regard to differentiated S100-positive chondrocytes within a cartilaginous matrix, with strong collagen type II expression and increased synthesis of proteoglycans. Finally, our innovative scaffold-free fusion culture technique supported enhanced chondrogenesis of human articular chondrocytes in vitro. These 3-D hyaline cartilage-like microtissues will be useful for in vitro studies of cartilage differentiation and regeneration, enabling optimization of functional tissue engineering and possibly contributing to the development of new approaches to treat traumatic cartilage defects or osteoarthritis.

  18. Patterned carbon nanotubes as a new three-dimensional scaffold for mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Bitirim, Verda Ceylan [Department of Molecular Biology and Genetics, Bilkent University, 06800, Ankara (Turkey); Kucukayan-Dogu, Gokce [Institute of Engineering and Science, Material Science and Nanotechnology Graduate Program, Bilkent University, 06800, Ankara (Turkey); Bengu, Erman [Department of Chemistry, Bilkent University, 06800, Ankara (Turkey); Akcali, Kamil Can, E-mail: akcali@fen.bilkent.edu.tr [Department of Molecular Biology and Genetics, Bilkent University, 06800, Ankara (Turkey); Bilgen, Bilkent University Genetics and Biotechnology Research Center, 06800, Ankara (Turkey)

    2013-07-01

    We investigated the cellular adhesive features of mesenchymal stem cells (MSC) on non-coated and collagen coated patterned and vertically aligned carbon nanotube (CNT) structures mimicking the natural extra cellular matrix (ECM). Patterning was achieved using the elasto-capillary induced by water treatment on the CNT arrays. After confirmation with specific markers both at transcript and protein levels, MSCs from different passages were seeded on either collagen coated or non-coated patterned CNTs. Adhesion and growth of MSCs on the patterned CNT arrays were examined using scanning electron microscopy image analysis and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) assays. The highest MSC count was observed on the non-coated patterned CNTs at passage zero, while decreasing numbers of MSCs were found at the later passages. Similarly, MTT assay results also revealed a decrease in the viability of the MSCs for the later passages. Overall, the cell count and viability experiments indicated that MSCs were able to better attach to non-coated patterned CNTs compared to those coated with collagen. Therefore, the patterned CNT surfaces can be potentially used as a scaffold mimicking the ECM environment for MSC growth which presents an alternative approach to MSC-based transplantation therapy applications. - Highlights: • Synthesized vertically aligned CNTs were patterned to be used as scaffold. • The growth of mesenchymal stem cells was achieved on the patterned CNTs. • The cell number was counted higher on the patterned CNTs than collagen coated CNTs. • The MTT assay results revealed the cell viability on the patterned CNTs.

  19. Patterned carbon nanotubes as a new three-dimensional scaffold for mesenchymal stem cells

    International Nuclear Information System (INIS)

    Bitirim, Verda Ceylan; Kucukayan-Dogu, Gokce; Bengu, Erman; Akcali, Kamil Can

    2013-01-01

    We investigated the cellular adhesive features of mesenchymal stem cells (MSC) on non-coated and collagen coated patterned and vertically aligned carbon nanotube (CNT) structures mimicking the natural extra cellular matrix (ECM). Patterning was achieved using the elasto-capillary induced by water treatment on the CNT arrays. After confirmation with specific markers both at transcript and protein levels, MSCs from different passages were seeded on either collagen coated or non-coated patterned CNTs. Adhesion and growth of MSCs on the patterned CNT arrays were examined using scanning electron microscopy image analysis and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) assays. The highest MSC count was observed on the non-coated patterned CNTs at passage zero, while decreasing numbers of MSCs were found at the later passages. Similarly, MTT assay results also revealed a decrease in the viability of the MSCs for the later passages. Overall, the cell count and viability experiments indicated that MSCs were able to better attach to non-coated patterned CNTs compared to those coated with collagen. Therefore, the patterned CNT surfaces can be potentially used as a scaffold mimicking the ECM environment for MSC growth which presents an alternative approach to MSC-based transplantation therapy applications. - Highlights: • Synthesized vertically aligned CNTs were patterned to be used as scaffold. • The growth of mesenchymal stem cells was achieved on the patterned CNTs. • The cell number was counted higher on the patterned CNTs than collagen coated CNTs. • The MTT assay results revealed the cell viability on the patterned CNTs

  20. Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

    OpenAIRE

    Zhang, Haifeng; Mao, Xiyuan; Du, Zijing; Jiang, Wenbo; Han, Xiuguo; Zhao, Danyang; Han, Dong; Li, Qingfeng

    2016-01-01

    Abstract We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500??m and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, ?-tricalcium phosphate (?-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, prolife...

  1. Human endothelial cell growth and phenotypic expression on three dimensional poly(lactide-co-glycolide) sintered microsphere scaffolds for bone tissue engineering.

    Science.gov (United States)

    Jabbarzadeh, Ehsan; Jiang, Tao; Deng, Meng; Nair, Lakshmi S; Khan, Yusuf M; Laurencin, Cato T

    2007-12-01

    Bone tissue engineering offers promising alternatives to repair and restore tissues. Our laboratory has employed poly(lactide-co-glycolide) PLAGA microspheres to develop a three dimensional (3-D) porous bioresorbable scaffold with a biomimetic pore structure. Osseous healing and integration with the surrounding tissue depends in part on new blood vessel formation within the porous structure. Since endothelial cells play a key role in angiogenesis (formation of new blood vessels from pre-existing vasculature), the purpose of this study was to better understand human endothelial cell attachment, viability, growth, and phenotypic expression on sintered PLAGA microsphere scaffold. Scanning electron microscopy (SEM) examination showed cells attaching to the surface of microspheres and bridging the pores between the microspheres. Cell proliferation studies indicated that cell number increased during early stages and reached a plateau between days 10 and 14. Immunofluorescent staining for actin showed that cells were proliferating three dimensionally through the scaffolds while staining for PECAM-1 (platelet endothelial cell adhesion molecule) displayed typical localization at cell-cell contacts. Gene expression analysis showed that endothelial cells grown on PLAGA scaffolds maintained their normal characteristic phenotype. The cell proliferation and phenotypic expression were independent of scaffold pore architecture. These results demonstrate that PLAGA sintered microsphere scaffolds can support the growth and biological functions of human endothelial cells. The insights from this study should aid future studies aimed at enhancing angiogenesis in three dimensional tissue engineered scaffolds.

  2. Assessing the morphology of selective laser melted NiTi-scaffolds for a three-dimensional quantification of the one-way shape memory effect

    Science.gov (United States)

    Bormann, Therese; de Wild, Michael; Beckmann, Felix; Müller, Bert

    2013-04-01

    NiTi is promising for the use as bone scaffold, because the pseudoelasticity or the one- and two-way shape memory effect in the physiological window can mechanically stimulate the adherent cells. Such stimuli can enhance osseointegration and might reduce stress shielding associated with load bearing implants. The present study is based on the additive manufacturing technique of selective laser melting (SLM) to fabricate three-dimensional NiTi scaffolds. We demonstrate that the morphology of the scaffolds can be quantified using synchrotron radiation-based micro computed tomography (SRμCT) and sophisticated registration software. Comparing the CAD file with the SLM scaffolds, quality factors are derived. With respect to the CAD file, the overlap corresponds to (92.5 +/- 0.6) %. (7.4 +/- 0.42) % of material was missing and (48.9 +/- 2.3) % of excess material found. This means that the actual scaffold is less porous than expected, a fact that has to be considered for the scaffold design. In order to quantify the shape memory effect during the shape recovery process, we acquired radiographs rotating an initially deformed scaffold in angular steps of 0.2 degree during controlled heating. The continuously acquired radiographs were combined to tomography data, showing that the quality factors evolved with temperature as the scaffold height, measured by conventional thermo-mechanical analysis. Furthermore, the data comprise the presence of compressive and tensile local strains in the three-dimensional scaffolds to be compared with the physiological situation.

  3. Stromal cell derived factor-1α (SDF-1α) directed chemoattraction of transiently CXCR4 overexpressing mesenchymal stem cells into functionalized three-dimensional biomimetic scaffolds

    DEFF Research Database (Denmark)

    Thieme, S; Ryser, Martin; Gentsch, Marcus

    2009-01-01

    Three-dimensional (3D) bone substitute material should not only serve as scaffold in large bone defects but also attract mesenchymal stem cells, a subset of bone marrow stromal cells (BMSCs) that are able to form new bone tissue. An additional crucial step is to attract BMSCs from the surface int...... invaded up to 250 mum into SDF-1alpha-releasing 3D scaffolds, whereas CXCR4-overexpressing BMSC invaded up to 500 mum within 5 days. Thus, the SDF-1alpha/CXCR4 chemoattraction system can be used to efficiently recruit BMSCs into SDF-1alpha-releasing 3D scaffolds in vitro and in vivo....

  4. Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

    Science.gov (United States)

    Zhang, Haifeng; Mao, Xiyuan; Du, Zijing; Jiang, Wenbo; Han, Xiuguo; Zhao, Danyang; Han, Dong; Li, Qingfeng

    2016-01-01

    We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo. The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.

  5. Using Polymeric Scaffolds for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Alida Abruzzo

    2014-01-01

    Full Text Available With the high occurrence of cardiovascular disease and increasing numbers of patients requiring vascular access, there is a significant need for small-diameter (<6 mm inner diameter vascular graft that can provide long-term patency. Despite the technological improvements, restenosis and graft thrombosis continue to hamper the success of the implants. Vascular tissue engineering is a new field that has undergone enormous growth over the last decade and has proposed valid solutions for blood vessels repair. The goal of vascular tissue engineering is to produce neovessels and neoorgan tissue from autologous cells using a biodegradable polymer as a scaffold. The most important advantage of tissue-engineered implants is that these tissues can grow, remodel, rebuild, and respond to injury. This review describes the development of polymeric materials over the years and current tissue engineering strategies for the improvement of vascular conduits.

  6. Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations

    Directory of Open Access Journals (Sweden)

    Jana Markhoff

    2015-08-01

    Full Text Available In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM or electron beam melting (EBM varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration.

  7. Influence of Different Three-Dimensional Open Porous Titanium Scaffold Designs on Human Osteoblasts Behavior in Static and Dynamic Cell Investigations.

    Science.gov (United States)

    Markhoff, Jana; Wieding, Jan; Weissmann, Volker; Pasold, Juliane; Jonitz-Heincke, Anika; Bader, Rainer

    2015-08-24

    In the treatment of osseous defects micro-structured three-dimensional materials for bone replacement serve as leading structure for cell migration, proliferation and bone formation. The scaffold design and culture conditions are crucial for the limited diffusion distance of nutrients and oxygen. In static culture, decreased cell activity and irregular distribution occur within the scaffold. Dynamic conditions entail physical stimulation and constant medium perfusion imitating physiological nutrient supply and metabolite disposal. Therefore, we investigated the influence of different scaffold configurations and cultivation methods on human osteoblasts. Cells were seeded on three-dimensional porous Ti-6Al-4V scaffolds manufactured with selective laser melting (SLM) or electron beam melting (EBM) varying in porosity, pore size and basic structure (cubic, diagonal, pyramidal) and cultured under static and dynamic conditions. Cell viability, migration and matrix production were examined via mitochondrial activity assay, fluorescence staining and ELISA. All scaffolds showed an increasing cell activity and matrix production under static conditions over time. Expectations about the dynamic culture were only partially fulfilled, since it enabled proliferation alike the static one and enhanced cell migration. Overall, the SLM manufactured scaffold with the highest porosity, small pore size and pyramidal basic structure proved to be the most suitable structure for cell proliferation and migration.

  8. Changes in expression of cartilaginous genes during chondrogenesis of Wharton's jelly mesenchymal stem cells on three-dimensional biodegradable poly(L-lactide-co-glycolide) scaffolds.

    Science.gov (United States)

    Paduszyński, Piotr; Aleksander-Konert, Ewelina; Zajdel, Alicja; Wilczok, Adam; Jelonek, Katarzyna; Witek, Andrzej; Dzierżewicz, Zofia

    2016-01-01

    In cartilage tissue regeneration, it is important to develop biodegradable scaffolds that provide a structural and logistic template for three-dimensional cultures of chondrocytes. In this study, we evaluated changes in expression of cartilaginous genes during in vitro chondrogenic differentiation of WJ-MSCs on PLGA scaffolds. The biocompatibility of the PLGA material was investigated using WJ-MSCs by direct and indirect contact methods according to the ISO 10993-5 standard. PLGA scaffolds were fabricated by the solvent casting/salt-leaching technique. We analyzed expression of chondrogenic genes of WJ-MSCs after a 21-day culture. The results showed the biocompatibility of PLGA and confirmed the usefulness of PLGA as material for fabrication of 3D scaffolds that can be applied for WJ-MSC culture. The in vitro penetration and colonization of the scaffolds by WJ-MSCs were assessed by confocal microscopy. The increase in cell number demonstrated that scaffolds made of PLGA copolymers enabled WJ-MSC proliferation. The obtained data showed that as a result of chondrogenesis of WJ-MSCs on the PLGA scaffold the expression of the key markers collagen type II and aggrecan was increased. The observed changes in transcriptional activity of cartilaginous genes suggest that the PLGA scaffolds may be applied for WJ-MSC differentiation. This primary study suggests that chondrogenic capacity of WJ-MSCs cultured on the PLGA scaffolds can be useful for cell therapy of cartilage.

  9. Finite-element design and optimization of a three-dimensional tetrahedral porous titanium scaffold for the reconstruction of mandibular defects.

    Science.gov (United States)

    Luo, Danmei; Rong, Qiguo; Chen, Quan

    2017-09-01

    Reconstruction of segmental defects in the mandible remains a challenge for maxillofacial surgery. The use of porous scaffolds is a potential method for repairing these defects. Now, additive manufacturing techniques provide a solution for the fabrication of porous scaffolds with specific geometrical shapes and complex structures. The goal of this study was to design and optimize a three-dimensional tetrahedral titanium scaffold for the reconstruction of mandibular defects. With a fixed strut diameter of 0.45mm and a mean cell size of 2.2mm, a tetrahedral structural porous scaffold was designed for a simulated anatomical defect derived from computed tomography (CT) data of a human mandible. An optimization method based on the concept of uniform stress was performed on the initial scaffold to realize a minimal-weight design. Geometric and mechanical comparisons between the initial and optimized scaffold show that the optimized scaffold exhibits a larger porosity, 81.90%, as well as a more homogeneous stress distribution. These results demonstrate that tetrahedral structural titanium scaffolds are feasible structures for repairing mandibular defects, and that the proposed optimization scheme has the ability to produce superior scaffolds for mandibular reconstruction with better stability, higher porosity, and less weight. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  10. Three-Dimensional Scaffold Chip with Thermosensitive Coating for Capture and Reversible Release of Individual and Cluster of Circulating Tumor Cells.

    Science.gov (United States)

    Cheng, Shi-Bo; Xie, Min; Chen, Yan; Xiong, Jun; Liu, Ya; Chen, Zhen; Guo, Shan; Shu, Ying; Wang, Ming; Yuan, Bi-Feng; Dong, Wei-Guo; Huang, Wei-Hua

    2017-08-01

    Tumor metastasis is attributed to circulating tumor cells (CTC) or CTC clusters. Many strategies have hitherto been designed to isolate CTCs, but there are few methods that can capture and gently release CTC clusters as efficient as single CTCs. Herein, we developed a three-dimensional (3D) scaffold chip with thermosensitive coating for high-efficiency capture and release of individual and cluster CTCs. The 3D scaffold chip successfully combines the specific recognition and physically obstructed effect of 3D scaffold structure to significantly improve cell clusters capture efficiency. Thermosensitive gelatin hydrogel uniformly coated on the scaffold dissolves at 37 °C quickly, and the captured cells are gently released from chip with high viability. Notably, this platform was applied to isolate CTCs from cancer patients' blood samples. This allows global DNA and RNA methylation analysis of collected single CTC and CTC clusters, indicating the great potential of this platform in cancer diagnosis and downstream analysis at the molecular level.

  11. [Mechanical properties of polylactic acid/beta-tricalcium phosphate composite scaffold with double channels based on three-dimensional printing technique].

    Science.gov (United States)

    Lian, Qin; Zhuang, Pei; Li, Changhai; Jin, Zhongmin; Li, Dichen

    2014-03-01

    To improve the poor mechanical strength of porous ceramic scaffold, an integrated method based on three-dimensional (3-D) printing technique is developed to incorporate the controlled double-channel porous structure into the polylactic acid/beta-tricalcium phosphate (PLA/beta-TCP) reinforced composite scaffolds (double-channel composite scaffold) to improve their tissue regeneration capability and the mechanical properties. The designed double-channel structure inside the ceramic scaffold consisted of both primary and secondary micropipes, which parallel but un-connected. The set of primary channels was used for cell ingrowth, while the set of secondary channels was used for the PLA perfusion. Integration technology of 3-D printing technique and gel-casting was firstly used to fabricate the double-channel ceramic scaffolds. PLA/beta-TCP composite scaffolds were obtained by the polymer gravity perfusion process to pour PLA solution into the double-channel ceramic scaffolds through the secondary channel set. Microscope, porosity, and mechanical experiments for the standard samples were used to evaluate the composite properties. The ceramic scaffold with only the primary channel (single-channel scaffold) was also prepared as a control. Morphology observation results showed that there was no PLA inside the primary channels of the double-channel composite scaffolds but a dense interface layer between PLA and beta-TCP obviously formed on the inner wall of the secondary channels by the PLA penetration during the perfusion process. Finite element simulation found that the compressive strength of the double-channel composite scaffold was less than that of the single-channel scaffold; however, mechanical tests found that the maximum compressive strength of the double-channel composite scaffold [(21.25 +/- 1.15) MPa] was higher than that of the single-channel scaffold[ (9.76 +/- 0.64) MPa]. The double-channel composite scaffolds fabricated by 3-D printing technique have

  12. Surface biofunctionalization of three-dimensional porous poly(lactic acid) scaffold using chitosan/OGP coating for bone tissue engineering.

    Science.gov (United States)

    Zeng, Sen; Ye, Jianhua; Cui, Zhixiang; Si, Junhui; Wang, Qianting; Wang, Xiaofeng; Peng, Kaiping; Chen, Wenzhe

    2017-08-01

    As one of the stimulators on bone formation, osteogenic growth peptide (OGP) improves both proliferation and differentiation of the bone cells in vitro and in vivo. The aim of this work was the preparation of three dimensional porous poly(lactic acid) (PLA) scaffold with high porosity from PLA-dioxane-water ternary system with the use of vacuum-assisted solvent casting, phase separation, solvent extraction and particle leaching methods. Then, by surface coating of PLA scaffold with chitosan (CS)/OGP solution, biofunctionalization of PLA scaffold had been completed for application in bone regeneration. The effects of frozen temperature (-20, -50, -80°C) and PLA solution concentration (10, 12, 14wt%) on the microstructure, water absorption, porosity, hydrophilicity, mechanical properties, and biocompatibility of PLA and CS/OGP/PLA scaffold were investigated. Results showed that both PLA and CS/OGP/PLA scaffolds have an interconnected network structure and a porosity of up to 96.1% and 91.5%, respectively. The CS/OGP/PLA scaffold exhibited better hydrophilicity and mechanical properties than that of uncoated PLA scaffold. Moreover, the results of cell culture test showed that CS/OGP coating could stimulate the proliferation and growth of osteoblast cells on CS/OGP/PLA scaffold. These finding suggested that the surface biofunctionalization by CS/OGP coating layer could be an effective method on enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering application and the developed porous CS/OGP/PLA scaffold should be considered as alternative biomaterials for bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Biodegradable polycaprolactone-chitosan three-dimensional scaffolds fabricated by melt stretching and multilayer deposition for bone tissue engineering: assessment of the physical properties and cellular response

    International Nuclear Information System (INIS)

    Thuaksuban, Nuttawut; Nuntanaranont, Thongchai; Suttapreyasri, Srisurang; Pattanachot, Wachirapan; Cheung, Lim Kwong

    2011-01-01

    Fabrication of polycaprolactone (PCL)-chitosan (CS) three-dimensional (3D) scaffolds using the novel technique of melt stretching and multilayer deposition was introduced. In brief, firstly, the PCL-CS monofilaments containing 0% (pure PCL), 10%, 20% and 30% CS by weight were fabricated by melting and stretching processes. Secondly, the desired multilayer (3D) scaffolds were fabricated by arranging and depositing the filaments. Physical properties of the filaments and the scaffolds were evaluated. MC3T3-E1 cell lines were seeded on the scaffolds to assess their proliferation. A typical micro-groove pattern was found on the surfaces of pure PCL filaments due to stretching. The filaments of PCL-30%CS had the highest tendency of fracture during stretching and could not be used to form the scaffold. Increasing CS proportions tended to reduce the micro-groove pattern, surface roughness, tensile strength and elasticity of the filaments, whilst compressive strength of the PCL-CS scaffolds was not affected. The average pore size and porosity of the scaffolds were 536.90 ± 17.91 μm and 45.99 ± 2.8% respectively. Over 60 days, degradation of the scaffolds gradually increased (p > 0.05). The more CS containing scaffolds were found to increase in water uptake, but decrease in degradation rate. During the culture period, the growth of the cells in PCL-CS groups was significantly higher than in the pure PCL group (p < 0.05). On culture-day 21, the growth in the PCL-20%CS group was significantly higher than the other groups (p < 0.05). In conclusion, the PCL-20%CS scaffolds obtained the optimum results in terms of physical properties and cellular response.

  14. Biodegradable polycaprolactone-chitosan three-dimensional scaffolds fabricated by melt stretching and multilayer deposition for bone tissue engineering: assessment of the physical properties and cellular response

    Energy Technology Data Exchange (ETDEWEB)

    Thuaksuban, Nuttawut; Nuntanaranont, Thongchai; Suttapreyasri, Srisurang [Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Prince of Songkla University, Kanjanavanij Road, Hatyai, Songkhla, 90112 (Thailand); Pattanachot, Wachirapan [Polymer Science Program, Faculty of Science, Prince of Songkla University, Kanjanavanij Road, Hatyai, Songkhla, 90112 (Thailand); Cheung, Lim Kwong, E-mail: nuttawut.t@psu.ac.t [Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, the University of Hong Kong, Hong Kong (China)

    2011-02-15

    Fabrication of polycaprolactone (PCL)-chitosan (CS) three-dimensional (3D) scaffolds using the novel technique of melt stretching and multilayer deposition was introduced. In brief, firstly, the PCL-CS monofilaments containing 0% (pure PCL), 10%, 20% and 30% CS by weight were fabricated by melting and stretching processes. Secondly, the desired multilayer (3D) scaffolds were fabricated by arranging and depositing the filaments. Physical properties of the filaments and the scaffolds were evaluated. MC3T3-E1 cell lines were seeded on the scaffolds to assess their proliferation. A typical micro-groove pattern was found on the surfaces of pure PCL filaments due to stretching. The filaments of PCL-30%CS had the highest tendency of fracture during stretching and could not be used to form the scaffold. Increasing CS proportions tended to reduce the micro-groove pattern, surface roughness, tensile strength and elasticity of the filaments, whilst compressive strength of the PCL-CS scaffolds was not affected. The average pore size and porosity of the scaffolds were 536.90 {+-} 17.91 {mu}m and 45.99 {+-} 2.8% respectively. Over 60 days, degradation of the scaffolds gradually increased (p > 0.05). The more CS containing scaffolds were found to increase in water uptake, but decrease in degradation rate. During the culture period, the growth of the cells in PCL-CS groups was significantly higher than in the pure PCL group (p < 0.05). On culture-day 21, the growth in the PCL-20%CS group was significantly higher than the other groups (p < 0.05). In conclusion, the PCL-20%CS scaffolds obtained the optimum results in terms of physical properties and cellular response.

  15. Osteoinduction and proliferation of bone-marrow stromal cells in three-dimensional poly (ε-caprolactone)/ hydroxyapatite/collagen scaffolds.

    Science.gov (United States)

    Wang, Ting; Yang, Xiaoyan; Qi, Xin; Jiang, Chaoyin

    2015-05-08

    Osteoinduction and proliferation of bone-marrow stromal cells (BMSCs) in three-dimensional (3D) poly(ε-caprolactone) (PCL) scaffolds have not been studied throughly and are technically challenging. This study aimed to optimize nanocomposites of 3D PCL scaffolds to provide superior adhesion, proliferation and differentiation environment for BMSCs in this scenario. BMSCs were isolated and cultured in a novel 3D tissue culture poly(ε-caprolactone) (PCL) scaffold coated with poly-lysine, hydroxyapatite (HAp), collagen and HAp/collagen. Cell morphology was observed and BMSC biomarkers for osteogenesis, osteoblast differentiation and activation were analyzed. Scanning Electron Microscope (SEM) micrographs showed that coating materials were uniformly deposited on the surface of PCL scaffolds and BMSCs grew and aggregated to form clusters during 3D culture. Both mRNA and protein levels of the key players of osteogenesis and osteoblast differentiation and activation, including runt-related transcription factor 2 (Runx2), alkaline phosphates (ALP), osterix, osteocalcin, and RANKL, were significantly higher in BMSCs seeded in PCL scaffolds coated with HAp or HAp/collagen than those seeded in uncoated PCL scaffolds, whereas the expression levels were not significantly different in collagen or poly-lysine coated PCL scaffolds. In addition, poly-lysine, collagen, HAp/collagen, and HAp coated PCL scaffolds had significantly more viable cells than uncoated PCL scaffolds, especially scaffolds with HAp/collagen and collagen-alone coatings. That BMSCs in HAp or HAp/collagen PCL scaffolds had remarkably higher ALP activities than those in collagen-coated alone or uncoated PCL scaffolds indicating higher osteogenic differentiation levels of BMSCs in HAp or HAp/collagen PCL scaffolds. Moreover, morphological changes of BMSCs after four-week of 3D culture confirmed that BMSCs successfully differentiated into osteoblast with spread-out phenotype in HAp/collagen coated PCL scaffolds

  16. Preparation, structural characterization, and in vitro cell studies of three-dimensional SiO2-CaO binary glass scaffolds built ofultra-small nanofibers.

    Science.gov (United States)

    Luo, Honglin; Li, Wei; Ao, Haiyong; Li, Gen; Tu, Junpin; Xiong, Guangyao; Zhu, Yong; Wan, Yizao

    2017-07-01

    Three-dimensional (3D) nanofibrous scaffolds hold great promises in tissue engineering and regenerative medicine. In this work, for the first time, 3D SiO 2 -CaO binary glass nanofibrous scaffolds have been fabricated via a combined method of template-assisted sol-gel and calcination by using bacterial cellulose as the template. SEM with EDS, TEM, and AFM confirm that the molar ratio of Ca to Si and fiber diameter of the resultant SiO 2 -CaO nanofibers can be controlled by immersion time in the solution of tetraethyl orthosilicate and ethanol. The optimal immersion time was 6h which produced the SiO 2 -CaO binary glass containing 60at.% Si and 40at.% Ca (named 60S40C). The fiber diameter of 60S40C scaffold is as small as 29nm. In addition, the scaffold has highly porous 3D nanostructure with dominant mesopores at 10.6nm and macropores at 20μm as well as a large BET surface area (240.9m 2 g -1 ), which endow the 60S40C scaffold excellent biocompatibility and high ALP activity as revealed by cell studies using osteoblast cells. These results suggest that the 60S40C scaffold has great potential in bone tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Fabrication of three-dimensional poly(ε-caprolactone) scaffolds with hierarchical pore structures for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qingchun [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Luo, Houyong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Yan [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhou, Yan [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai 200237 (China); Ye, Zhaoyang, E-mail: zhaoyangye@ecust.edu.cn [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai 200237 (China); Tan, Wensong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai 200237 (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2013-05-01

    The physical properties of tissue engineering scaffolds such as microstructures play important roles in controlling cellular behaviors and neotissue formation. Among them, the pore size stands out as a key determinant factor. In the present study, we aimed to fabricate porous scaffolds with pre-defined hierarchical pore sizes, followed by examining cell growth in these scaffolds. This hierarchical porous microstructure was implemented via integrating different pore-generating methodologies, including salt leaching and thermal induced phase separation (TIPS). Specifically, large (L, 200–300 μm), medium (M, 40–50 μm) and small (S, < 10 μm) pores were able to be generated. As such, three kinds of porous scaffolds with a similar porosity of ∼ 90% creating pores of either two (LS or MS) or three (LMS) different sizes were successfully prepared. The number fractions of different pores in these scaffolds were determined to confirm the hierarchical organization of pores. It was found that the interconnectivity varied due to the different pore structures. Besides, these scaffolds demonstrated similar compressive moduli under dry and hydrated states. The adhesion, proliferation, and spatial distribution of human fibroblasts within the scaffolds during a 14-day culture were evaluated with MTT assay and fluorescence microscopy. While all three scaffolds well supported the cell attachment and proliferation, the best cell spatial distribution inside scaffolds was achieved with LMS, implicating that such a controlled hierarchical microstructure would be advantageous in tissue engineering applications. Highlights: ► The scaffolds with dual-pore and triple-pore structures were fabricated. ► Triple-pore structure had better interconnectivity than dual-pore structures. ► Better cell migration and distribution were found on the triple-pore structures. ► The medium pore size (45–50 μm) was appropriate for cell migration. ► Scaffolds with triple-pore structure

  18. Fabrication of triple-layered bifurcated vascular scaffold with a certain degree of three-dimensional structure

    Science.gov (United States)

    Liu, Yuanyuan; Jiang, Weijian; Yang, Yang; Pu, Huayan; Peng, Yan; Xin, Liming; Zhang, Yi; Sun, Yu

    2018-01-01

    Constructing vascular scaffolds is important in tissue engineering. However, scaffolds with characteristics such as multiple layers and a certain degree of spatial morphology still cannot be readily constructed by current vascular scaffolds fabrication techniques. This paper presents a three-layered bifurcated vascular scaffold with a curved structure. The technique combines 3D printed molds and casting hydrogel and fugitive ink to create vessel-mimicking constructs with customizable structural parameters. Compared with other fabrication methods, the technique can create more native-like 3D geometries. The diameter and wall thickness of the fabricated constructs can be independently controlled, providing a feasible approach for vascular scaffold construction. Enzymatically-crosslinked gelatin was used as the scaffold material. The morphology and mechanical properties were evaluated. Human umbilical cord derived endothelial cells (HUVECs) were seeded on the scaffolds and cultured for 72 h. Cell viability and morphology were assessed. The results showed that the proposed process had good application potentials, and will hopefully provide a feasible approach for constructing vascular scaffolds.

  19. Parameters in three-dimensional osteospheroids of telomerized human mesenchymal (stromal) stem cells grown on osteoconductive scaffolds that predict in vivo bone-forming potential

    DEFF Research Database (Denmark)

    Burns, Jorge S; Hansen, Pernille Lund; Larsen, Kenneth H

    2010-01-01

    Osteoblastic differentiation of human mesenchymal stem cells (hMSC) in monolayer culture is artefactual, lacking an organized bone-like matrix. We present a highly reproducible microwell protocol generating three-dimensional ex vivo multicellular aggregates of telomerized hMSC (hMSC-telomerase re......Osteoblastic differentiation of human mesenchymal stem cells (hMSC) in monolayer culture is artefactual, lacking an organized bone-like matrix. We present a highly reproducible microwell protocol generating three-dimensional ex vivo multicellular aggregates of telomerized hMSC (h......, was deposited in the scaffold concavities. Here, mature osteoblasts stained positively for differentiated osteoblast markers TAZ, biglycan, osteocalcin, and phospho-AKT. Quantification of collagen birefringence and relatively high expression of genes for matrix proteins, including type I collagen, biglycan...

  20. Proliferation and chondrogenic differentiation of CD105-positive enriched rat synovium-derived mesenchymal stem cells in three-dimensional porous scaffolds

    International Nuclear Information System (INIS)

    Qi Jun; Chen Anmin; You Hongbo; Li Kunpeng; Zhang Di; Guo Fengjing

    2011-01-01

    Stem cell-based tissue engineering has provided an alternative strategy to treat cartilage lesions, and synovium-derived mesenchymal stem cells (SMSCs) are considered as a promising cell source for cartilage repair. In this study, the SMSCs were isolated from rat synovium, and CD105-positive (CD105 + ) cells were enriched using magnetic activated cell sorting. Sorted cells were subsequently seeded onto the chitosan-alginate composite three-dimensional (3D) porous scaffolds and cultured in chondrogenic culture medium in the presence of TGF-β 3 and BMP-2 for 2 weeks in vitro. After 2 weeks in culture, scanning electron microscopy results showed that cells attached and proliferated well on scaffolds, and secreted extracellular matrix were also observed. From day 7 to day 14, the total DNA and glucosaminoglycan content of the cells cultured in scaffolds were found to have increased significantly, and cell cycle analyses revealed that the percentage of cells in the S and G2/M phases increased and the percentage of cells in the G0/G1 phase decreased. Compared with non-sorted cells, the sorted cells cultured in scaffolds underwent more chondrogenic differentiation, as evidenced by higher expression of type II collagen and Sox9 at the protein and mRNA levels. The results suggest that CD105 + enriched SMSCs may be a potential cell source for cartilage tissue engineering, and the chitosan-alginate composite 3D porous scaffold could provide a favorable microenvironment for supporting proliferation and chondrogenic differentiation of cells.

  1. Human Adipose-Derived Stem Cells on Rapid Prototyped Three-Dimensional Hydroxyapatite/Beta-Tricalcium Phosphate Scaffold.

    Science.gov (United States)

    Canciani, Elena; Dellavia, Claudia; Ferreira, Lorena Maria; Giannasi, Chiara; Carmagnola, Daniela; Carrassi, Antonio; Brini, Anna Teresa

    2016-05-01

    In the study, we assess a rapid prototyped scaffold composed of 30/70 hydroxyapatite (HA) and beta-tricalcium-phosphate (β-TCP) loaded with human adipose-derived stem cells (hASCs) to determine cell proliferation, differentiation toward osteogenic lineage, adhesion and penetration on/into the scaffold.In this in vitro study, hASCs isolated from fat tissue discarded after plastic surgery were expanded, characterized, and then loaded onto the scaffold. Cells were tested for: viability assay (Alamar Blue at days 3, 7 and Live/Dead at day 32), differentiation index (alkaline phosphatase activity at day 14), scaffold adhesion (standard error of the mean analysis at days 5 and 18), and penetration (ground sections at day 32).All the hASC populations displayed stemness markers and the ability to differentiate toward adipogenic and osteogenic lineages.Cellular vitality increased between 3 and 7 days, and no inhibitory effect by HA/β-TCP was observed. Under osteogenic stimuli, scaffold increased alkaline phosphatase activity of +243% compared with undifferentiated samples. Human adipose-derived stem cells adhered on HA/β-TCP surface through citoplasmatic extensions that occupied the macropores and built networks among them. Human adipose derived stem cells were observed in the core of HA/β-TCP. The current combination of hASCs and HA/β-TCP scaffold provided encouraging results. If authors' data will be confirmed in preclinical models, the present engineering approach could represent an interesting tool in treating large bone defects.

  2. Magnetic resonance imaging tracking of human adipose derived stromal cells within three-dimensional scaffolds for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    C Lalande

    2011-04-01

    Full Text Available For bone tissue engineering, human Adipose Derived Stem Cells (hADSCs are proposed to be associated with a scaffold for promoting bone regeneration. After implantation, cellularised scaffolds require a non-invasive method for monitoring their fate in vivo. The purpose of this study was to use Magnetic Resonance Imaging (MRI-based tracking of these cells, labelled with magnetic agents for in vivo longitudinal assessment. hADSCs were isolated from adipose tissue and labelled with USPIO-rhodamine (Ultrasmall SuperParamagnetic Iron Oxide. USPIO internalisation, absence of toxicity towards hADSCs, and osteogenic differentiation of the labelled cells were evaluated in standard culture conditions. Labelled cells were then seeded within a 3D porous polysaccharide-based scaffold and imaged in vitro using fluorescence microscopy and MRI. Cellularised scaffolds were implanted subcutaneously in nude mice and MRI analyses were performed from 1 to 28 d after implantation. In vitro, no effect of USPIO labelling on cell viability and osteogenic differentiation was found. USPIO were efficiently internalised by hADSCs and generated a high T2* contrast. In vivo MRI revealed that hADSCs remain detectable until 28 d after implantation and could migrate from the scaffold and colonise the area around it. These data suggested that this scaffold might behave as a cell carrier capable of both holding a cell fraction and delivering cells to the site of implantation. In addition, the present findings evidenced that MRI is a reliable technique to validate cell-seeding procedures in 3D porous scaffolds, and to assess the fate of hADSCs transplanted in vivo.

  3. Melt Electrospinning Writing of Three-dimensional Poly(ε-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications.

    Science.gov (United States)

    Wunner, Felix M; Bas, Onur; Saidy, Navid T; Dalton, Paul D; Pardo, Elena M De-Juan; Hutmacher, Dietmar W

    2017-12-23

    This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

  4. Three-dimensional poly (ε-caprolactone)/hydroxyapatite/collagen scaffolds incorporating bone marrow mesenchymal stem cells for the repair of bone defects

    International Nuclear Information System (INIS)

    Qi, Xin; Huang, Yinjun; Zhang, Jieyuan; Cao, Jiaqing; Jin, Xiangyun; Huang, Jinghuan; Li, Xiaolin; Wang, Ting; Han, Dan

    2016-01-01

    We previously demonstrated that three-dimensional (3D) hydroxyapatite (HAP)-collagen (COL)-coated poly(ε-caprolactone) (PCL) scaffolds (HAP-COL-PCL) possess appropriate nano-structures, surface roughness, and nutrients, providing a favorable environment for osteogenesis. However, the effect of using 3D HAP-COL-PCL scaffolds incorporating BMSCs for the repair of bone defects in rats has been not evaluated. 3D PCL scaffolds coated with HAP, collagen or HAP/COL and incorporating BMSCs were implanted into calvarial defects. At 12 weeks after surgery, the rats were sacrificed and crania were harvested to assess the bone defect repair using microcomputed tomography (micro-CT), histology, immunohistochemistry and sequential fluorescent labeling analysis. 3D micro-CT reconstructed images and quantitative analysis showed that HAP-COL-PCL groups possessed better bone-forming capacity than HAP-PCL groups or COL-PCL groups. Fluorescent labeling analysis revealed the percentage of tetracycline labeling, alizarin red labeling, and calcein labeling in HAP-COL-PCL groups were all greater than in the other two groups (P  <  0.05), and the result was confirmed by immunohistochemical staining and histological analysis of bone regeneration. This study demonstrates that 3D HAP-COL-PCL scaffolds incorporating BMSCs markedly enhance bone regeneration of bone defects in rats. (paper)

  5. Three-dimensional polymer scaffolds for enhanced differentiation of human mesenchymal stem cells to hepatocyte-like cells: a comparative study.

    Science.gov (United States)

    Chitrangi, Swati; Nair, Prabha; Khanna, Aparna

    2017-08-01

    Stem cell-based tissue engineering has emerged as a promising avenue for the treatment of liver diseases and as drug metabolism and toxicity models in drug discovery and development. The in vitro simulation of a micro-environmental niche for hepatic differentiation remains elusive, due to lack of information about crucial factors for the stem cell niche. For generation of functional hepatocytes, an in vivo three-dimensional (3D) micro-environment and architecture should be reproduced. Towards this, we fabricated three scaffolds as dextran-gelatin (DG1), chitosan-hyaluronic acid (CH1) and gelatin-vinyl acetate (GEVAC). Hepatic differentiation of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) was induced by culturing hUC-MSCs on these scaffolds. The scaffolds support hepatic differentiation by mimicking the native extracellular matrix (ECM) micro-environment and architecture to facilitate 3D cell-cell and cell-matrix interactions. The expression of hepatic markers, glycogen storage, urea production, albumin secretion and cytochrome P450 (CYP450) activity indicated the hepatic differentiation of hUC-MSCs. The differentiated hUC-MSCs on the 3D scaffolds formed hepatospheroids (3D hepatocyte aggregates), as illustrated by scanning electron microscopy (SEM), confocal microscopy and cytoskeleton organization. It was observed that the 3D scaffolds supported improved cell morphology, expression of hepatic markers and metabolic activities, as compared to Matrigel-coated plates. To the best of our knowledge, this is the first report demonstrating the use of a well-characterized scaffold (GEVAC) for enhanced differentiation of hUC-MSCs to hepatocyte-like cells (HLCs). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. A combinatorial variation in surface chemistry and pore size of three-dimensional porous poly(ε-caprolactone) scaffolds modulates the behaviors of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yingdi; Tan, Ke; Zhou, Yan; Ye, Zhaoyang, E-mail: zhaoyangye@ecust.edu.cn; Tan, Wen-Song

    2016-02-01

    Biomaterial properties play significant roles in controlling cellular behaviors. The objective of the present study was to investigate how pore size and surface chemistry of three-dimensional (3D) porous scaffolds regulate the fate of mesenchymal stem cells (MSCs) in vitro in combination. First, on poly(ε-caprolactone) (PCL) films, the hydrolytic treatment was found to stimulate the adhesion, spreading and proliferation of human MSCs (hMSCs) in comparison with pristine films, while the aminolysis showed mixed effects. Then, 3D porous PCL scaffolds with varying pore sizes (100–200 μm, 200–300 μm and 300–450 μm) were fabricated and subjected to either hydrolysis or aminolysis. It was found that a pore size of 200–300 μm with hydrolysis in 3D scaffolds was the most favorable condition for growth of hMSCs. Importantly, while a pore size of 200–300 μm with hydrolysis for 1 h supported the best osteogenic differentiation of hMSCs, the chondrogenic differentiation was greatest in scaffolds with a pore size of 300–450 μm and treated with aminolysis for 1 h. Taken together, these results suggest that surface chemistry and pore size of 3D porous scaffolds may potentially have a synergistic impact on the behaviors of MSCs. - Highlights: • Surface chemistry of poly(ε-caprolactone) films actively modulates MSC behaviors. • Varying surface chemistry and pore size in combination is enabled in 3D scaffolds. • Surface chemistry and pore size potentially dictate MSC fates in synergy.

  7. A combinatorial variation in surface chemistry and pore size of three-dimensional porous poly(ε-caprolactone) scaffolds modulates the behaviors of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Zhao, Yingdi; Tan, Ke; Zhou, Yan; Ye, Zhaoyang; Tan, Wen-Song

    2016-01-01

    Biomaterial properties play significant roles in controlling cellular behaviors. The objective of the present study was to investigate how pore size and surface chemistry of three-dimensional (3D) porous scaffolds regulate the fate of mesenchymal stem cells (MSCs) in vitro in combination. First, on poly(ε-caprolactone) (PCL) films, the hydrolytic treatment was found to stimulate the adhesion, spreading and proliferation of human MSCs (hMSCs) in comparison with pristine films, while the aminolysis showed mixed effects. Then, 3D porous PCL scaffolds with varying pore sizes (100–200 μm, 200–300 μm and 300–450 μm) were fabricated and subjected to either hydrolysis or aminolysis. It was found that a pore size of 200–300 μm with hydrolysis in 3D scaffolds was the most favorable condition for growth of hMSCs. Importantly, while a pore size of 200–300 μm with hydrolysis for 1 h supported the best osteogenic differentiation of hMSCs, the chondrogenic differentiation was greatest in scaffolds with a pore size of 300–450 μm and treated with aminolysis for 1 h. Taken together, these results suggest that surface chemistry and pore size of 3D porous scaffolds may potentially have a synergistic impact on the behaviors of MSCs. - Highlights: • Surface chemistry of poly(ε-caprolactone) films actively modulates MSC behaviors. • Varying surface chemistry and pore size in combination is enabled in 3D scaffolds. • Surface chemistry and pore size potentially dictate MSC fates in synergy.

  8. Direct printing of patterned three-dimensional ultrafine fibrous scaffolds by stable jet electrospinning for cellular ingrowth

    International Nuclear Information System (INIS)

    Yuan, Huihua; Zhou, Qihui; Li, Biyun; Bao, Min; Lou, Xiangxin; Zhang, Yanzhong

    2015-01-01

    Electrospinning has been widely used to produce ultrafine fibers in microscale and nanoscale; however, traditional electrospinning processes are currently beset by troublesome limitations in fabrication of 3D periodic porous structures because of the chaotic nature of the electrospinning jet. Here we report a novel strategy to print 3D poly(L-lactic acid) (PLLA) ultrafine fibrous scaffolds with the fiber diameter of approximately 2 μm by combining a stable jet electrospinning method and an X-Y stage technique. Our approach allows linearly deposited electrospun ultrafine fibers to assemble into 3D structures with tunable pore sizes and desired patterns. Process conditions (e.g., plotting speed, feeding rate, and collecting distance) were investigated in order to achieve stable jet printing of ultrafine PLLA fibers. The proposed 3D scaffold was successfully used for cell penetration and growth, demonstrating great potential for tissue engineering applications. (paper)

  9. Three-dimensional bioprinting using self-assembling scalable scaffold-free “tissue strands” as a new bioink

    Science.gov (United States)

    Yu, Yin; Moncal, Kazim K.; Li, Jianqiang; Peng, Weijie; Rivero, Iris; Martin, James A.; Ozbolat, Ibrahim T.

    2016-01-01

    Recent advances in bioprinting have granted tissue engineers the ability to assemble biomaterials, cells, and signaling molecules into anatomically relevant functional tissues or organ parts. Scaffold-free fabrication has recently attracted a great deal of interest due to the ability to recapitulate tissue biology by using self-assembly, which mimics the embryonic development process. Despite several attempts, bioprinting of scale-up tissues at clinically-relevant dimensions with closely recapitulated tissue biology and functionality is still a major roadblock. Here, we fabricate and engineer scaffold-free scalable tissue strands as a novel bioink material for robotic-assisted bioprinting technologies. Compare to 400 μm-thick tissue spheroids bioprinted in a liquid delivery medium into confining molds, near 8 cm-long tissue strands with rapid fusion and self-assemble capabilities are bioprinted in solid form for the first time without any need for a scaffold or a mold support or a liquid delivery medium, and facilitated native-like scale-up tissues. The prominent approach has been verified using cartilage strands as building units to bioprint articular cartilage tissue. PMID:27346373

  10. Highly concentrated collagen solutions leading to transparent scaffolds of controlled three-dimensional organizations for corneal epithelial cell colonization.

    Science.gov (United States)

    Tidu, Aurélien; Ghoubay-Benallaoua, Djida; Teulon, Claire; Asnacios, Sophie; Grieve, Kate; Portier, François; Schanne-Klein, Marie-Claire; Borderie, Vincent; Mosser, Gervaise

    2018-05-29

    This study aimed at controlling both the organization and the transparency of dense collagen scaffolds making use of the lyotropic mesogen properties of collagen. Cholesteric or plywood-like liquid crystal phases were achieved using mixtures of acetic and hydrochloric acids as solvents. The critical pH at which the switch between the two phases occurred was around pH = 3. The use of the two acids led to fibrillated collagen I scaffolds, whose visual aspect ranged from opaque to transparent. Rheological investigations showed that viscoelastic properties of the plywood-like solutions were optimized for molding due to faster recovery. They also confirmed the correlation between the elastic modulus and the diameter of collagen fibrils obtained after fibrillogenesis under ammonia vapor. Human corneal epithelial cells, grown from donor limbal explants, were cultured both on transparent plywood-like matrices and on human amniotic membranes for 14 days. The development of corneal epithelium and the preservation of epithelial stem cells were checked by optical microscopy, colony formation assay, immuno-fluorescence and quantitative polymerase chain reaction. A higher level of amplification of limbal stem cells was obtained with collagen matrices compared with amniotic membranes, showing the high biocompatibility of our scaffolds. We therefore suggest that collagen solutions presenting both plywood-like organization and transparency might be of interest for biomedical applications in ophthalmology.

  11. Proliferation and chondrogenic differentiation of CD105-positive enriched rat synovium-derived mesenchymal stem cells in three-dimensional porous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Qi Jun; Chen Anmin; You Hongbo; Li Kunpeng; Zhang Di; Guo Fengjing, E-mail: fjguo@tjh.tjmu.edu.cn [Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    2011-02-15

    Stem cell-based tissue engineering has provided an alternative strategy to treat cartilage lesions, and synovium-derived mesenchymal stem cells (SMSCs) are considered as a promising cell source for cartilage repair. In this study, the SMSCs were isolated from rat synovium, and CD105-positive (CD105{sup +}) cells were enriched using magnetic activated cell sorting. Sorted cells were subsequently seeded onto the chitosan-alginate composite three-dimensional (3D) porous scaffolds and cultured in chondrogenic culture medium in the presence of TGF-{beta}{sub 3} and BMP-2 for 2 weeks in vitro. After 2 weeks in culture, scanning electron microscopy results showed that cells attached and proliferated well on scaffolds, and secreted extracellular matrix were also observed. From day 7 to day 14, the total DNA and glucosaminoglycan content of the cells cultured in scaffolds were found to have increased significantly, and cell cycle analyses revealed that the percentage of cells in the S and G2/M phases increased and the percentage of cells in the G0/G1 phase decreased. Compared with non-sorted cells, the sorted cells cultured in scaffolds underwent more chondrogenic differentiation, as evidenced by higher expression of type II collagen and Sox9 at the protein and mRNA levels. The results suggest that CD105{sup +} enriched SMSCs may be a potential cell source for cartilage tissue engineering, and the chitosan-alginate composite 3D porous scaffold could provide a favorable microenvironment for supporting proliferation and chondrogenic differentiation of cells.

  12. The role of three-dimensional pure bovine gelatin scaffolds in tendon healing, modeling, and remodeling: an in vivo investigation with potential clinical value.

    Science.gov (United States)

    Oryan, Ahmad; Sharifi, Pardis; Moshiri, Ali; Silver, Ian A

    2017-09-01

    Large tendon defects involving extensive tissue loss present complex clinical problems. Surgical reconstruction of such injuries is normally performed by transplanting autogenous and allogenous soft tissues that are expected to remodel to mimic a normal tendon. However, the use of grafts has always been associated with significant limitations. Tissue engineering employing artificial scaffolds may provide acceptable alternatives. Gelatin is a hydrolyzed form of collagen that is bioactive, biodegradable, and biocompatible. The present study has investigated the suitability of gelatin scaffold for promoting healing of a large tendon-defect model in rabbits. An experimental model of a large tendon defect was produced by partial excision of the Achilles tendon of the left hind leg in adult rabbits. To standardize and stabilize the length of the tendon defect a modified Kessler core suture was anchored in the sectioned tendon ends. The defects were either left untreated or filled with three-dimensional gelatin scaffold. Before euthanasia 60 days after injury, the progress of healing was evaluated clinically. Samples of healing tendon were harvested at autopsy and evaluated by gross, histopathologic, scanning, and transmission electron microscopy, and by biomechanical testing. The treated animals showed superior weight-bearing and physical activity compared with those untreated, while frequency of peritendinous adhesions around the healing site was reduced. The gelatin scaffold itself was totally degraded and replaced by neo-tendon that morphologically had significantly greater numbers, diameters, density, and maturation of collagen fibrils, fibers, and fiber bundles than untreated tendon scar tissue. It also had mechanically higher ultimate load, yield load, stiffness, maximum stress and elastic modulus, when compared to the untreated tendons. Gelatin scaffold may be a valuable option in surgical reconstruction of large tendon defects.

  13. Manufacture of degradable polymeric scaffolds for bone regeneration.

    Science.gov (United States)

    Ge, Zigang; Jin, Zhaoxia; Cao, Tong

    2008-06-01

    Many innovative technology platforms for promoting bone regeneration have been developed. A common theme among these is the use of scaffolds to provide mechanical support and osteoconduction. Scaffolds can be either ceramic or polymer-based, or composites of both classes of material. Both ceramics and polymers have their own merits and drawbacks, and a better solution may be to synergize the advantageous properties of both materials within composite scaffolds. In this current review, after a brief introduction of the anatomy and physiology of bone, different strategies of fabricating polymeric scaffolds for bone regeneration, including traditional and solid free-form fabrication, are critically discussed and compared, while focusing on the advantages and disadvantages of individual techniques.

  14. Manufacture of degradable polymeric scaffolds for bone regeneration

    International Nuclear Information System (INIS)

    Ge Zigang; Jin Zhaoxia; Cao Tong

    2008-01-01

    Many innovative technology platforms for promoting bone regeneration have been developed. A common theme among these is the use of scaffolds to provide mechanical support and osteoconduction. Scaffolds can be either ceramic or polymer-based, or composites of both classes of material. Both ceramics and polymers have their own merits and drawbacks, and a better solution may be to synergize the advantageous properties of both materials within composite scaffolds. In this current review, after a brief introduction of the anatomy and physiology of bone, different strategies of fabricating polymeric scaffolds for bone regeneration, including traditional and solid free-form fabrication, are critically discussed and compared, while focusing on the advantages and disadvantages of individual techniques. (topical review)

  15. CD44+/CD24- breast cancer cells exhibit phenotypic reversion in three-dimensional self-assembling peptide RADA16 nanofiber scaffold

    Directory of Open Access Journals (Sweden)

    Mi K

    2015-04-01

    Full Text Available Kun Mi,1 Zhihua Xing2 1Department of Biochemistry and Molecular Biology, Sichuan Cancer Hospital and Institute, 2Laboratory of Ethnopharmacology, Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu, People’s Republic of China Background: Self-assembling peptide nanofiber scaffolds have been shown to be a ­permissive biological material for tissue repair, cell proliferation, differentiation, etc. Recently, a subpopulation (CD44+/CD24- of breast cancer cells has been reported to have stem/progenitor cell properties. The aim of this study was to investigate whether this subpopulation of cancer cells have different phenotypes in self-assembling COCH3-RADARADARADARADA-CONH2 (RADA16 peptide nanofiber scaffold compared with Matrigel® (BD Biosciences, Two Oak Park, Bedford, MA, USA and collagen I.Methods: CD44 and CD24 expression was determined by flow cytometry. Cell proliferation was measured by 5-bromo-2'-deoxyuridine assay and DNA content measurement. Immunostaining was used to indicate the morphologies of cells in three-dimensional (3D cultures of different scaffolds and the localization of β-catenin in the colonies. Western blot was used to determine the expression of signaling proteins. In vitro migration assay and inoculation into nude mice were used to evaluate invasion and tumorigenesis in vivo.Results: The breast cancer cell line MDA-MB-435S contained a high percentage (>99% of CD44+/CD24- cells, which exhibited phenotypic reversion in 3D RADA16 nanofiber scaffold compared with collagen I and Matrigel. The newly formed reverted acini-like colonies reassembled a basement membrane and reorganized their cytoskeletons. At the same time, cells cultured and embedded in RADA16 peptide scaffold exhibited growth arrest. Also, they exhibited different migration potential, which links their migration ability with their cellular morphology. Consistent with studies in vitro, the in vivo tumor

  16. Cell-derived matrix coatings for polymeric scaffolds.

    Science.gov (United States)

    Decaris, Martin L; Binder, Bernard Y; Soicher, Matthew A; Bhat, Archana; Leach, J Kent

    2012-10-01

    Cells in culture deposit a complex extracellular matrix that remains intact following decellularization and possesses the capacity to modulate cell phenotype. The direct application of such decellularized matrices (DMs) to 3D substrates is problematic, as transport issues influence the homogeneous deposition, decellularization, and modification of DM surface coatings. In an attempt to address this shortcoming, we hypothesized that DMs deposited by human mesenchymal stem cells (MSCs) could be transferred to the surface of polymeric scaffolds while maintaining their capacity to direct cell fate. The ability of the transferred DM (tDM)-coated scaffolds to enhance the osteogenic differentiation of undifferentiated and osteogenically induced MSCs under osteogenic conditions in vitro was confirmed. tDM-coated scaffolds increased MSC expression of osteogenic marker genes (BGLAP, IBSP) and intracellular alkaline phosphatase production. In addition, undifferentiated MSCs deposited significantly more calcium when seeded onto tDM-coated scaffolds compared with control scaffolds. MSC-seeded tDM-coated scaffolds subcutaneously implanted in nude rats displayed significantly higher blood vessel density after 2 weeks compared with cells on uncoated scaffolds, but we did not observe significant differences in mineral deposition after 8 weeks. These data demonstrate that DM-coatings produced in 2D culture can be successfully transferred to 3D substrates and retain their capacity to modulate cell phenotype.

  17. SiO2 and ZnO dopants in three-dimensionally printed tricalcium phosphate bone tissue engineering scaffolds enhance osteogenesis and angiogenesis in vivo.

    Science.gov (United States)

    Fielding, Gary; Bose, Susmita

    2013-11-01

    Calcium phosphate (CaP) scaffolds with three-dimensionally-interconnected pores play an important role in mechanical interlocking and biological fixation in bone implant applications. CaPs alone, however, are only osteoconductive (able to guide bone growth). Much attention has been given to the incorporation of biologics and pharmacologics to add osteoinductive (able to cause new bone growth) properties to CaP materials. Because biologics and pharmacologics are generally delicate compounds and also subject to increased regulatory scrutiny, there is a need to investigate alternative methods to introduce osteoinductivity to CaP materials. In this study silica (SiO2) and zinc oxide (ZnO) have been incorporated into three-dimensional printed β-tricalcium phosphate (β-TCP) scaffolds to investigate their potential to trigger osteoinduction in vivo. Silicon and zinc are trace elements that are common in bone and have also been shown to have many beneficial properties, from increased bone regeneration to angiogenesis. Implants were placed in bicortical femur defects introduced to a murine model for up to 16 weeks. The addition of dopants into TCP increased the capacity for new early bone formation by modulating collagen I production and osteocalcin production. Neovascularization was found to be up to three times more than the pure TCP control group. The findings from this study indicate that the combination of SiO2 and ZnO dopants in TCP may be a viable alternative to introducing osteoinductive properties to CaPs. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Three-dimensional mesostructures as high-temperature growth templates, electronic cellular scaffolds, and self-propelled microrobots

    Science.gov (United States)

    Yan, Zheng; Han, Mengdi; Shi, Yan; Badea, Adina; Yang, Yiyuan; Kulkarni, Ashish; Hanson, Erik; Kandel, Mikhail E.; Wen, Xiewen; Zhang, Fan; Luo, Yiyue; Lin, Qing; Zhang, Hang; Guo, Xiaogang; Huang, Yuming; Nan, Kewang; Jia, Shuai; Oraham, Aaron W.; Mevis, Molly B.; Lim, Jaeman; Guo, Xuelin; Gao, Mingye; Ryu, Woomi; Yu, Ki Jun; Nicolau, Bruno G.; Petronico, Aaron; Rubakhin, Stanislav S.; Lou, Jun; Ajayan, Pulickel M.; Thornton, Katsuyo; Popescu, Gabriel; Fang, Daining; Sweedler, Jonathan V.; Braun, Paul V.; Zhang, Haixia; Nuzzo, Ralph G.; Huang, Yonggang; Zhang, Yihui; Rogers, John A.

    2017-11-01

    Recent work demonstrates that processes of stress release in prestrained elastomeric substrates can guide the assembly of sophisticated 3D micro/nanostructures in advanced materials. Reported application examples include soft electronic components, tunable electromagnetic and optical devices, vibrational metrology platforms, and other unusual technologies, each enabled by uniquely engineered 3D architectures. A significant disadvantage of these systems is that the elastomeric substrates, while essential to the assembly process, can impose significant engineering constraints in terms of operating temperatures and levels of dimensional stability; they also prevent the realization of 3D structures in freestanding forms. Here, we introduce concepts in interfacial photopolymerization, nonlinear mechanics, and physical transfer that bypass these limitations. The results enable 3D mesostructures in fully or partially freestanding forms, with additional capabilities in integration onto nearly any class of substrate, from planar, hard inorganic materials to textured, soft biological tissues, all via mechanisms quantitatively described by theoretical modeling. Illustrations of these ideas include their use in 3D structures as frameworks for templated growth of organized lamellae from AgCl-KCl eutectics and of atomic layers of WSe2 from vapor-phase precursors, as open-architecture electronic scaffolds for formation of dorsal root ganglion (DRG) neural networks, and as catalyst supports for propulsive systems in 3D microswimmers with geometrically controlled dynamics. Taken together, these methodologies establish a set of enabling options in 3D micro/nanomanufacturing that lie outside of the scope of existing alternatives.

  19. Significance of soluble growth factors in the chondrogenic response of human umbilical cord matrix stem cells in a porous three dimensional scaffold

    Directory of Open Access Journals (Sweden)

    RS Nirmal

    2013-11-01

    Full Text Available Stem cell based tissue engineering has emerged as a promising strategy for articular cartilage regeneration. Foetal derived mesenchymal stem cells (MSCs with their ease of availability, pluripotency and high expansion potential have been demonstrated to be an attractive cell source over adult MSCs. However, there is a need for optimisation of chondrogenic signals to direct the differentiation of these multipotent MSCs to chondrogenic lineage. In this study we have demonstrated the in vitro chondrogenesis of human umbilical cord matrix MSCs in three dimensional PVA-PCL (polyvinyl alcohol-polycaprolactone scaffolds in the presence of the individual growth factors TGFβ1, TGFβ3, IGF, BMP2 and their combination with BMP2. Gene expression, histology and immunohistology were evaluated after 28 d culture. The induced cells showed the feature of chondrocytes in their morphology and expression of typical chondrogenic extracellular matrix molecules. Moreover, the real-time PCR assay has shown the expression of gene markers of chondrogenesis, SOX9, collagen type II and aggrecan. The expression of collagen type I and collagen type X was also evaluated. This study has demonstrated the successful chondrogenic induction of human umbilical cord MSCs in 3D scaffolds. Interestingly, the growth factor combination of TGF-β3 and BMP-2 was found to be more effective for chondrogenesis as shown by the real-time PCR studies. The findings of this study suggest the importance of using growth factor combinations for successful chondrogenic differentiation of umbilical cord MSCs.

  20. Phase I/II Trial of Autologous Bone Marrow Stem Cell Transplantation with a Three-Dimensional Woven-Fabric Scaffold for Periodontitis

    Directory of Open Access Journals (Sweden)

    Shunsuke Baba

    2016-01-01

    Full Text Available Regenerative medicine is emerging as a promising option, but the potential of autologous stem cells has not been investigated well in clinical settings of periodontal treatment. In this clinical study, we evaluated the safety and efficacy of a new regenerative therapy based on the surgical implantation of autologous mesenchymal stem cells (MSCs with a biodegradable three-dimensional (3D woven-fabric composite scaffold and platelet-rich plasma (PRP. Ten patients with periodontitis, who required a surgical procedure for intrabony defects, were enrolled in phase I/II trial. Once MSCs were implanted in each periodontal intrabony defect, the patients were monitored during 36 months for a medical exam including laboratory tests of blood and urine samples, changes in clinical attachment level, pocket depth, and linear bone growth (LBG. All three parameters improved significantly during the entire follow-up period (p<0.0001, leading to an average LBG of 4.7 mm after 36 months. Clinical mobility measured by Periotest showed a decreasing trend after the surgery. No clinical safety problems attributable to the investigational MSCs were identified. This clinical trial suggests that the stem cell therapy using MSCs-PRP/3D woven-fabric composite scaffold may constitute a novel safe and effective regenerative treatment option for periodontitis.

  1. Bone regeneration in critical bone defects using three-dimensionally printed β-tricalcium phosphate/hydroxyapatite scaffolds is enhanced by coating scaffolds with either dipyridamole or BMP-2.

    Science.gov (United States)

    Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N

    2017-02-01

    Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL -1 ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017. © 2015 Wiley Periodicals, Inc.

  2. [Biological evaluation of three-dimensional printed co-poly lactic acid/glycolic acid/tri-calcium phosphate scaffold for bone reconstruction].

    Science.gov (United States)

    Li, S Y; Zhou, M; Lai, Y X; Geng, Y M; Cao, S S; Chen, X M

    2016-11-09

    Objective: To biologically evaluate the three-dimensional(3D) printed co-poly lactic acid/glycolic acid/tri-calcium phosphate(PLGA/TCP) scaffold which could be used for repairing oral and maxillofacial bone defects, and to provide experimental evidence for its further research and clinical application. Methods: PLGA/TCP scaffolds were fabricated using low temperature rapid prototyping technique. Micro-CT and scanning electron microscope(SEM) were used to characterize the surface morphology. MC3T3-E1 cells were seeded onto the scaffold and stained with the rhodamine phalloidin and calcein acetomethoxy. After that, confocal laser scanning microscope was exploited to observe the features and viability of the cells. Moreover, the cells were co-cultured with the extract of PLGA/TCP and complete medium, respectively. The proliferation capability of the cells was assessed by the cell counting kit-8 (CCK-8) on the 1st, 2nd, and 3rd day. The PLGA/TCP scaffolds incorporated with recombinant human bone morphogenetic protein-2(rhBMP-2) of 0, 30, 60 μg(i.e. blank control group, low-dose group and high-dose group) were implanted into the latissimus dorsi muscle of the rats, and 6 weeks later, the samples were harvested to estimate the volume and pattern of new bone. Results: The 3D printed PLGA/TCP scaffold possessed a regular and well-defined porous stereo-structure with porosity of (73±3)%. Micro-CT and SEM showed that pore size were (379±32) and (453±29) μm respectively, and distance between layers were (452± 24) and (415±25) μm, and cylinder diameter were (342±24) and (350±28) μm. It also exhibited excellent cell adhesion and growth ability on the exterior and inner surface through rhodamine phalloidin and calcein acetomethoxy staining. The CCK-8 test demonstrated that the absorbance value of extract group on the 1st and 2nd day(0.51±0.08 and 0.63±0.09) were significantly higher than those in the blank control group(0.39± 0.05 and 0.53±0.05)( P 0.05) on the 3

  3. Three-dimensional printing and deformation behavior of low-density target structures by two-photon polymerization

    Science.gov (United States)

    Liu, Ying; Stein, Ori; Campbell, John H.; Jiang, Lijia; Petta, Nicole; Lu, Yongfeng

    2017-08-01

    Two-photon polymerization (2PP), a 3D nano to microscale additive manufacturing process, is being used for the first time to fabricate small custom experimental packages ("targets") to support laser-driven high-energy-density (HED) physics research. Of particular interest is the use of 2PP to deterministically print low-density, low atomic-number (CHO) polymer matrices ("foams") at millimeter scale with sub-micrometer resolution. Deformation during development and drying of the foam structures remains a challenge when using certain commercial photo-resins; here we compare use of acrylic resins IP-S and IP-Dip. The mechanical strength of polymeric beam and foam structures is examined particularly the degree of deformation that occurs during the development and drying processes. The magnitude of the shrinkage in the two resins in quantified by printing sample structures and by use of FEA to simulate the deformation. Capillary drying forces are shown to be small and likely below the elastic limit of the core foam structure. In contrast the substantial shrinkage in IP-Dip ( 5-10%) cause large shear stresses and associated plastic deformation particularly near constrained boundaries such as the substrate and locations with sharp density variation. The inherent weakness of stitching boundaries is also evident and in certain cases can lead to delamination. Use of IP-S shows marked reduction in deformation with a minor loss of print resolution

  4. Three-dimensional printed PLA scaffold and human gingival stem cell-derived extracellular vesicles: a new tool for bone defect repair.

    Science.gov (United States)

    Diomede, Francesca; Gugliandolo, Agnese; Cardelli, Paolo; Merciaro, Ilaria; Ettorre, Valeria; Traini, Tonino; Bedini, Rossella; Scionti, Domenico; Bramanti, Alessia; Nanci, Antonio; Caputi, Sergio; Fontana, Antonella; Mazzon, Emanuela; Trubiani, Oriana

    2018-04-13

    The role of bone tissue engineering in the field of regenerative medicine has been a main research topic over the past few years. There has been much interest in the use of three-dimensional (3D) engineered scaffolds (PLA) complexed with human gingival mesenchymal stem cells (hGMSCs) as a new therapeutic strategy to improve bone tissue regeneration. These devices can mimic a more favorable endogenous microenvironment for cells in vivo by providing 3D substrates which are able to support cell survival, proliferation and differentiation. The present study evaluated the in vitro and in vivo capability of bone defect regeneration of 3D PLA, hGMSCs, extracellular vesicles (EVs), or polyethyleneimine (PEI)-engineered EVs (PEI-EVs) in the following experimental groups: 3D-PLA, 3D-PLA + hGMSCs, 3D-PLA + EVs, 3D-PLA + EVs + hGMSCs, 3D-PLA + PEI-EVs, 3D-PLA + PEI-EVs + hGMSCs. The structural parameters of the scaffold were evaluated using both scanning electron microscopy and nondestructive microcomputed tomography. Nanotopographic surface features were investigated by means of atomic force microscopy. Scaffolds showed a statistically significant mass loss along the 112-day evaluation. Our in vitro results revealed that both 3D-PLA + EVs + hGMSCs and 3D-PLA + PEI-EVs + hGMSCs showed no cytotoxicity. However, 3D-PLA + PEI-EVs + hGMSCs exhibited greater osteogenic inductivity as revealed by morphological evaluation and transcriptomic analysis performed by next-generation sequencing (NGS). In addition, in vivo results showed that 3D-PLA + PEI-EVs + hGMSCs and 3D-PLA + PEI-EVs scaffolds implanted in rats subjected to cortical calvaria bone tissue damage were able to improve bone healing by showing better osteogenic properties. These results were supported also by computed tomography evaluation that revealed the repair of bone calvaria damage. The re-establishing of the integrity of the bone lesions could be a

  5. Ultra-high-aspect-orthogonal and tunable three dimensional polymeric nanochannel stack array for BioMEMS applications

    Science.gov (United States)

    Heo, Joonseong; Kwon, Hyukjin J.; Jeon, Hyungkook; Kim, Bumjoo; Kim, Sung Jae; Lim, Geunbae

    2014-07-01

    Nanofabrication technologies have been a strong advocator for new scientific fundamentals that have never been described by traditional theory, and have played a seed role in ground-breaking nano-engineering applications. In this study, we fabricated ultra-high-aspect (~106 with O(100) nm nanochannel opening and O(100) mm length) orthogonal nanochannel array using only polymeric materials. Vertically aligned nanochannel arrays in parallel can be stacked to form a dense nano-structure. Due to the flexibility and stretchability of the material, one can tune the size and shape of the nanochannel using elongation and even roll the stack array to form a radial-uniformly distributed nanochannel array. The roll can be cut at discretionary lengths for incorporation with a micro/nanofluidic device. As examples, we demonstrated ion concentration polarization with the device for Ohmic-limiting/overlimiting current-voltage characteristics and preconcentrated charged species. The density of the nanochannel array was lower than conventional nanoporous membranes, such as anodic aluminum oxide membranes (AAO). However, accurate controllability over the nanochannel array dimensions enabled multiplexed one microstructure-on-one nanostructure interfacing for valuable biological/biomedical microelectromechanical system (BioMEMS) platforms, such as nano-electroporation.Nanofabrication technologies have been a strong advocator for new scientific fundamentals that have never been described by traditional theory, and have played a seed role in ground-breaking nano-engineering applications. In this study, we fabricated ultra-high-aspect (~106 with O(100) nm nanochannel opening and O(100) mm length) orthogonal nanochannel array using only polymeric materials. Vertically aligned nanochannel arrays in parallel can be stacked to form a dense nano-structure. Due to the flexibility and stretchability of the material, one can tune the size and shape of the nanochannel using elongation and even

  6. Shortest multiple disconnected path for the analysis of entanglements in two- and three-dimensional polymeric systems

    Science.gov (United States)

    Kröger, Martin

    2005-06-01

    We present an algorithm which returns a shortest path and related number of entanglements for a given configuration of a polymeric system in 2 or 3 dimensions. Rubinstein and Helfand, and later Everaers et al. introduced a concept to extract primitive paths for dense polymeric melts made of linear chains (a multiple disconnected multibead 'path'), where each primitive path is defined as a path connecting the (space-fixed) ends of a polymer under the constraint of non-interpenetration (excluded volume) between primitive paths of different chains, such that the multiple disconnected path fulfills a minimization criterion. The present algorithm uses geometrical operations and provides a—model independent—efficient approximate solution to this challenging problem. Primitive paths are treated as 'infinitely' thin (we further allow for finite thickness to model excluded volume), and tensionless lines rather than multibead chains, excluded volume is taken into account without a force law. The present implementation allows to construct a shortest multiple disconnected path (SP) for 2D systems (polymeric chain within spherical obstacles) and an optimal SP for 3D systems (collection of polymeric chains). The number of entanglements is then simply obtained from the SP as either the number of interior kinks, or from the average length of a line segment. Further, information about structure and potentially also the dynamics of entanglements is immediately available from the SP. We apply the method to study the 'concentration' dependence of the degree of entanglement in phantom chain systems. Program summaryTitle of program:Z Catalogue number:ADVG Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVG Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer for which the program is designed and others on which it has been tested: Silicon Graphics (Irix), Sun (Solaris), PC (Linux) Operating systems or monitors under which the

  7. Interplay between cellular activity and three-dimensional scaffold-cell constructs with different foam structure processed by electron beam melting.

    Science.gov (United States)

    Nune, Krishna C; Misra, R Devesh K; Gaytan, Sara M; Murr, Lawrence E

    2015-05-01

    The cellular activity, biological response, and consequent integration of scaffold-cell construct in the physiological system are governed by the ability of cells to adhere, proliferate, and biomineralize. In this regard, we combine cellular biology and materials science and engineering to fundamentally elucidate the interplay between cellular activity and interconnected three-dimensional foamed architecture obtained by a novel process of electron beam melting and computational tools. Furthermore, the organization of key proteins, notably, actin, vinclulin, and fibronectin, involved in cellular activity and biological functions and relationship with the structure was explored. The interconnected foamed structure with ligaments was favorable to cellular activity that includes cell attachment, proliferation, and differentiation. The primary rationale for favorable modulation of cellular functions is that the foamed structure provided a channel for migration and communication between cells leading to highly mineralized extracellular matrix (ECM) by the differentiating osteoblasts. The filopodial interaction amongst cells on the ligaments was a governing factor in the secretion of ECM, with consequent influence on maturation and mineralization. © 2014 Wiley Periodicals, Inc.

  8. Two-photon polymerization technique for microfabrication of CAD-designed 3D scaffolds from commercially available photosensitive materials.

    Science.gov (United States)

    Ovsianikov, Aleksandr; Schlie, Sabrina; Ngezahayo, Anaclet; Haverich, Axel; Chichkov, Boris N

    2007-01-01

    We report on recent advances in the fabrication of three-dimensional (3D) scaffolds for tissue engineering and regenerative medicine constructs using a two-photon polymerization technique (2PP). 2PP is a novel CAD/CAM technology allowing the fabrication of any computer-designed 3D structure from a photosensitive polymeric material. The flexibility of this technology and the ability to precisely define 3D construct geometry allows issues associated with vascularization and patient-specific tissue fabrication to be directly addressed. The fabrication of reproducible scaffold structures by 2PP is important for systematic studies of cellular processes and better understanding of in vitro tissue formation. In this study, 2PP was applied for the generation of 3D scaffold-like structures, using the photosensitive organic-inorganic hybrid polymer ORMOCER (ORganically MOdified CERamics) and epoxy-based SU8 materials. By comparing the proliferation rates of cells grown on flat material surfaces and under control conditions, it was demonstrated that ORMOCER and SU8 are not cytotoxic. Additional tests show that the DNA strand breaking of GFSHR-17 granulosa cells was not affected by the presence of ORMOCER. Furthermore, gap junction conductance measurements revealed that ORMOCER did not alter the formation of cell-cell junctions, critical for functional tissue growth. The possibilities of seeding 3D structures with cells were analysed. These studies demonstrate the great potential of 2PP technique for the manufacturing of scaffolds with controlled topology and properties.

  9. Interfacing polymeric scaffolds with primary pancreatic ductal adenocarcinoma cells to develop 3D cancer models

    NARCIS (Netherlands)

    Ricci, C.; Mota, C.M.; Moscato, S.; D' Alessandro, D.; Ugel, S.; Sartoris, S.; Bronte, V.; Boggi, U.; Campani, D.; Funel, N.; Moroni, Lorenzo; Danti, S.

    2014-01-01

    We analyzed the interactions between human primary cells from pancreatic ductal adenocarcinoma (PDAC) and polymeric scaffolds to develop 3D cancer models useful for mimicking the biology of this tumor. Three scaffold types based on two biocompatible polymeric formulations, such as poly(vinyl

  10. Three-dimensional culture and interaction of cancer cells and dendritic cells in an electrospun nano-submicron hybrid fibrous scaffold

    Directory of Open Access Journals (Sweden)

    Kim TE

    2016-03-01

    Full Text Available Tae-Eon Kim,1–3,* Chang Gun Kim,1–3,* Jin Soo Kim,4 Songwan Jin,4 Sik Yoon,5 Hae-Rahn Bae,6 Jeong-Hwa Kim,7,8 Young Hun Jeong,7,8 Jong-Young Kwak1–3 1Department of Pharmacology, School of Medicine, 2Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, South Korea; 3Immune Network Pioneer Research Center, Ajou University Medical Center, Suwon, South Korea; 4Department of Mechanical Engineering, Korea Polytechnic University, Gyeonggi, South Korea; 5Department of Anatomy, School of Medicine, Pusan National University, Yangsan, South Korea; 6Department of Physiology, College of Medicine, Dong-A University, Busan, South Korea; 7School of Mechanical Engineering, 8Department of Mechanical Engineering, Graduate School, Kyungpook National University, Daegu, South Korea *These authors contributed equally to this work Abstract: An artificial three-dimensional (3D culture system that mimics the tumor microenvironment in vitro is an essential tool for investigating the cross-talk between immune and cancer cells in tumors. In this study, we developed a 3D culture system using an electrospun poly(ε-caprolactone (PCL nanofibrous scaffold (NFS. A hybrid NFS containing an uninterrupted network of nano- and submicron-scale fibers (400 nm to 2 µm was generated by deposition onto a stainless steel mesh instead of an aluminum plate. The hybrid NFS contained multiplanar pores in a 3D structure. Surface-seeded mouse CT26 colon cancer cells and bone marrow-derived dendritic cells (BM-DCs were able to infiltrate the hybrid NFS within several hours. BM-DCs cultured on PCL nanofibers showed a baseline inactive form, and lipopolysaccharide (LPS-activated BM-DCs showed increased expression of CD86 and major histocompatibility complex Class II. Actin and phosphorylated FAK were enriched where unstimulated and LPS-stimulated BM-DCs contacted the fibers in the 3D hybrid NFS. When BM-DCs were cocultured with mitoxantrone-treated CT26 cells in

  11. Three-dimensional, bioactive, biodegradable, polymer-bioactive glass composite scaffolds with improved mechanical properties support collagen synthesis and mineralization of human osteoblast-like cells in vitro.

    Science.gov (United States)

    Lu, Helen H; El-Amin, Saadiq F; Scott, Kimberli D; Laurencin, Cato T

    2003-03-01

    In the past decade, tissue engineering-based bone grafting has emerged as a viable alternative to biological and synthetic grafts. The biomaterial component is a critical determinant of the ultimate success of the tissue-engineered graft. Because no single existing material possesses all the necessary properties required in an ideal bone graft, our approach has been to develop a three dimensional (3-D), porous composite of polylactide-co-glycolide (PLAGA) and 45S5 bioactive glass (BG) that is biodegradable, bioactive, and suitable as a scaffold for bone tissue engineering (PLAGA-BG composite). The objectives of this study were to examine the mechanical properties of a PLAGA-BG matrix, to evaluate the response of human osteoblast-like cells to the PLAGA-BG composite, and to evaluate the ability of the composite to form a surface calcium phosphate layer in vitro. Structural and mechanical properties of PLAGA-BG were measured, and the formation of a surface calcium phosphate layer was evaluated by surface analysis methods. The growth and differentiation of human osteoblast-like cells on PLAGA-BG were also examined. A hypothesis was that the combination of PLAGA with BG would result in a biocompatible and bioactive composite, capable of supporting osteoblast adhesion, growth and differentiation, with mechanical properties superior to PLAGA alone. The addition of bioactive glass granules to the PLAGA matrix resulted in a structure with higher compressive modulus than PLAGA alone. Moreover, the PLAGA-BA composite was found to be a bioactive material, as it formed surface calcium phosphate deposits in a simulated body fluid (SBF), and in the presence of cells and serum proteins. The composite supported osteoblast-like morphology, stained positively for alkaline phosphatase, and supported higher levels of Type I collagen synthesis than tissue culture polystyrene controls. We have successfully developed a degradable, porous, polymer bioactive glass composite possessing

  12. Regeneration of dental pulp/dentine complex with a three-dimensional and scaffold-free stem-cell sheet-derived pellet.

    Science.gov (United States)

    Na, Sijia; Zhang, Hao; Huang, Fang; Wang, Weiqi; Ding, Yin; Li, Dechao; Jin, Yan

    2016-03-01

    Dental pulp/dentine complex regeneration is indispensable to the construction of biotissue-engineered tooth roots and represents a promising approach to therapy for irreversible pulpitis. We used a tissue-engineering method based on odontogenic stem cells to design a three-dimensional (3D) and scaffold-free stem-cell sheet-derived pellet (CSDP) with the necessary physical and biological properties. Stem cells were isolated and identified and stem cells from root apical papilla (SCAPs)-based CSDPs were then fabricated and examined. Compact cell aggregates containing a high proportion of extracellular matrix (ECM) components were observed, and the CSDP culture time was prolonged. The expression of alkaline phosphatase (ALP), dentine sialoprotein (DSPP), bone sialoprotein (BSP) and runt-related gene 2 (RUNX2) mRNA was higher in CSDPs than in cell sheets (CSs), indicating that CSDPs have greater odonto/osteogenic potential. To further investigate this hypothesis, CSDPs and CSs were inserted into human treated dentine matrix fragments (hTDMFs) and transplanted into the subcutaneous space in the backs of immunodeficient mice, where they were cultured in vivo for 6 weeks. The root space with CSDPs was filled entirely with a dental pulp-like tissue with well-established vascularity, and a continuous layer of dentine-like tissue was deposited onto the existing dentine. A layer of odontoblast-like cells was found to express DSPP, ALP and BSP, and human mitochondria lined the surface of the newly formed dentine-like tissue. These results clearly indicate that SCAP-CSDPs with a mount of endogenous ECM have a strong capacity to form a heterotopic dental pulp/dentine complex in empty root canals; this method can be used in the fabrication of bioengineered dental roots and also provides an alternative treatment approach for pulp disease. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Three-dimensional culture and interaction of cancer cells and dendritic cells in an electrospun nano-submicron hybrid fibrous scaffold

    Science.gov (United States)

    Kim, Tae-Eon; Kim, Chang Gun; Kim, Jin Soo; Jin, Songwan; Yoon, Sik; Bae, Hae-Rahn; Kim, Jeong-Hwa; Jeong, Young Hun; Kwak, Jong-Young

    2016-01-01

    An artificial three-dimensional (3D) culture system that mimics the tumor microenvironment in vitro is an essential tool for investigating the cross-talk between immune and cancer cells in tumors. In this study, we developed a 3D culture system using an electrospun poly(ε-caprolactone) (PCL) nanofibrous scaffold (NFS). A hybrid NFS containing an uninterrupted network of nano- and submicron-scale fibers (400 nm to 2 µm) was generated by deposition onto a stainless steel mesh instead of an aluminum plate. The hybrid NFS contained multiplanar pores in a 3D structure. Surface-seeded mouse CT26 colon cancer cells and bone marrow-derived dendritic cells (BM-DCs) were able to infiltrate the hybrid NFS within several hours. BM-DCs cultured on PCL nanofibers showed a baseline inactive form, and lipopolysaccharide (LPS)-activated BM-DCs showed increased expression of CD86 and major histocompatibility complex Class II. Actin and phosphorylated FAK were enriched where unstimulated and LPS-stimulated BM-DCs contacted the fibers in the 3D hybrid NFS. When BM-DCs were cocultured with mitoxantrone-treated CT26 cells in a 3D hybrid NFS, BM-DCs sprouted cytoplasm to, migrated to, synapsed with, and engulfed mitoxantrone-treated CT26 cancer cells, which were similar to the naturally occurring cross-talk between these two types of cells. The 3D hybrid NFS developed here provides a 3D structure for coculture of cancer and immune cells. PMID:27042051

  14. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment

    Directory of Open Access Journals (Sweden)

    Omaima M Sabek

    2016-04-01

    Full Text Available Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow–derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland to support islet-like insulin-producing aggregates’ survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland—islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

  15. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment.

    Science.gov (United States)

    Sabek, Omaima M; Farina, Marco; Fraga, Daniel W; Afshar, Solmaz; Ballerini, Andrea; Filgueira, Carly S; Thekkedath, Usha R; Grattoni, Alessandro; Gaber, A Osama

    2016-01-01

    Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow-derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland) to support islet-like insulin-producing aggregates' survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland-islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

  16. Preparation of three-dimensional mesoporous polymer in situ polymerization solid phase microextraction fiber and its application to the determination of seven chlorophenols.

    Science.gov (United States)

    Wang, Xuemei; Wang, Huan; Huang, Pengfei; Ma, Xiaomin; Lu, Xiaoquan; Du, Xinzhen

    2017-01-06

    A superior solid-phase microextraction (SPME) fiber-coating material, three dimensional order mesoporous polymers with Ia-3d bicontinuous cubic structure (3D-OMPs) was in situ coated on a stainless steel wire by solvent evaporation induced self-assembly (EISA) and thermo-polymerization. Fourier-transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angel X-ray diffraction (SAXRD), N 2 adsorption-desorption transmission, and thermogravimetry analysis (TGA) were applied to the characterization of the synthesized 3D-OMPs coating. The performance and feasibility of the homemade fiber was evaluated through direct immersion (DI) SPME followed by high-performance liquid chromatography-UV detector (HPLC-UV) for the simultaneous extraction of seven chlorophenols in water samples. Under the optimum conditions, the prepared fiber exhibited excellent extraction properties as compared to three commercial fibers, the DI-SPME-HPLC-UV method showed low limits of detection (0.32-1.85μgL -1 ), wide linear ranges (5.0-1000μgL -1 ), and acceptable reproducibility (relative standard deviation, RSD<7.6% for one fiber, RSD<8.9% for fiber to fiber). Moreover, the method was further successfully applied to the analysis of seven CPs in real samples with good recoveries (80.5-99.5%) and satisfactory precisions (RSD<9.2%). It was confirmed that the proposed method has high sensitivity, outstanding selectivity and good reproducibility to the determination of trace CPs in the environmental water. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways

    Science.gov (United States)

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-03-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 μm interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 μm interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 μm interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 μm interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization.

  18. A three-dimensional hierarchical collagen scaffold fabricated by a combined solid freeform fabrication (SFF) and electrospinning process to enhance mesenchymal stem cell (MSC) proliferation

    International Nuclear Information System (INIS)

    Ahn, SeungHyun; Kim, GeunHyung; Koh, Young Ho

    2010-01-01

    Collagen has the advantage of being very similar to macromolecular substances that can be recognized and metabolized in the biological environment. Although the natural material has superior property for this purpose, its use to fabricate reproducible and pore-structure-controlled 3D structures, which are designed to allow the entry of sufficient cells and the easy diffusion of nutrients, has been limited due to its low processability. Here, we propose a hybrid technology that combines a cryogenic plotting system with an electrospinning process. Using this technique, an easily pore-size-controllable hierarchical 3D scaffold consisting of micro-sized highly porous collagen strands and micro/nano-sized collagen fibers was fabricated. The pore structure of the collagen scaffold was controlled by the collagen micro/nanofibers, which were layered in the scaffold. The hierarchical scaffolds were characterized with respect to initial cell attachment and proliferation of bone marrow-derived mesenchymal stem cells within the scaffolds. The hierarchical scaffold exhibited incredibly enhanced initial cell attachment and cell compactness between pores of the plotted scaffold relative to the normally designed 3D collagen scaffold.

  19. Imaging of cellular spread on a three-dimensional scaffold by means of a novel cell-labeling technique for high-resolution computed tomography

    NARCIS (Netherlands)

    Thimm, B.W.; Hofmann, S.; Schneider, P.; Carretta, R.; Müller, R.

    2012-01-01

    Computed tomography (CT) represents a truly three-dimensional (3D) imaging technique that can provide high-resolution images on the cellular level. Thus, one approach to detect single cells is X-ray absorption-based CT, where cells are labeled with a dense, opaque material providing the required

  20. Comparative Analysis of the Oxygen Supply and Viability of Human Osteoblasts in Three-Dimensional Titanium Scaffolds Produced by Laser-Beam or Electron-Beam Melting

    Directory of Open Access Journals (Sweden)

    Anika Jonitz-Heincke

    2013-11-01

    Full Text Available Synthetic materials for bone replacement must ensure a sufficient mechanical stability and an adequate cell proliferation within the structures. Hereby, titanium materials are suitable for producing patient-individual porous bone scaffolds by using generative techniques. In this in vitro study, the viability of human osteoblasts was investigated in porous 3D Ti6Al4V scaffolds, which were produced by electron-beam (EBM or laser-beam melting (LBM. For each examination, two cylindrical scaffolds (30 mm × 10 mm in size, 700 µm × 700 µm macropores were placed on each other and seeded with cells. The oxygen consumption and the acidification in the center of the structures were investigated by means of microsensors. Additionally, the synthesis of pro-collagen type 1 was analyzed. On the LBM titanium scaffolds, vital bone cells were detected in the center and in the periphery after 8 days of cultivation. In the EBM titanium constructs, however, vital cells were only visible in the center. During the cultivation period, the cells increasingly produced procollagen type 1 in both scaffolds. In comparison to the periphery, the oxygen content in the center of the scaffolds slightly decreased. Furthermore, a slight acidification of the medium was detectable. Compared to LBM, the EBM titanium scaffolds showed a less favorable behavior with regard to cell seeding.

  1. Improving osteointegration and osteogenesis of three-dimensional porous Ti6Al4V scaffolds by polydopamine-assisted biomimetic hydroxyapatite coating.

    Science.gov (United States)

    Li, Yong; Yang, Wei; Li, Xiaokang; Zhang, Xing; Wang, Cairu; Meng, Xiangfei; Pei, Yifeng; Fan, Xiangli; Lan, Pingheng; Wang, Chunhui; Li, Xiaojie; Guo, Zheng

    2015-03-18

    Titanium alloys with various porous structures can be fabricated by advanced additive manufacturing techniques, which are attractive for use as scaffolds for bone defect repair. However, modification of the scaffold surfaces, particularly inner surfaces, is critical to improve the osteointegration of these scaffolds. In this study, a biomimetic approach was employed to construct polydopamine-assisted hydroxyapatite coating (HA/pDA) onto porous Ti6Al4V scaffolds fabricated by the electron beam melting method. The surface modification was characterized with the field emission scanning electron microscopy, energy dispersive spectroscopy, water contact angle measurement, and confocal laser scanning microscopy. Attachment and proliferation of MC3T3-E1 cells on the scaffold surface were significantly enhanced by the HA/pDA coating compared to the unmodified surfaces. Additionally, MC3T3-E1 cells grown on the HA/pDA-coated Ti6Al4V scaffolds displayed significantly higher expression of runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 compared with bare Ti6Al4V scaffolds after culture for 14 days. Moreover, microcomputed tomography analysis and Van-Gieson staining of histological sections showed that HA/pDA coating on surfaces of porous Ti6Al4V scaffolds enhanced osteointegration and significantly promoted bone regeneration after implantation in rabbit femoral condylar defects for 4 and 12 weeks. Therefore, this study provides an alternative to biofunctionalized porous Ti6Al4V scaffolds with improved osteointegration and osteogenesis functions for orthopedic applications.

  2. Differentiation of human endometrial stem cells into urothelial cells on a three-dimensional nanofibrous silk-collagen scaffold: an autologous cell resource for reconstruction of the urinary bladder wall.

    Science.gov (United States)

    Shoae-Hassani, Alireza; Mortazavi-Tabatabaei, Seyed Abdolreza; Sharif, Shiva; Seifalian, Alexander Marcus; Azimi, Alireza; Samadikuchaksaraei, Ali; Verdi, Javad

    2015-11-01

    Reconstruction of the bladder wall via in vitro differentiated stem cells on an appropriate scaffold could be used in such conditions as cancer and neurogenic urinary bladder. This study aimed to examine the potential of human endometrial stem cells (EnSCs) to form urinary bladder epithelial cells (urothelium) on nanofibrous silk-collagen scaffolds, for construction of the urinary bladder wall. After passage 4, EnSCs were induced by keratinocyte growth factor (KGF) and epidermal growth factor (EGF) and seeded on electrospun collagen-V, silk and silk-collagen nanofibres. Later we tested urothelium-specific genes and proteins (uroplakin-Ia, uroplakin-Ib, uroplakin-II, uroplakin-III and cytokeratin 20) by immunocytochemistry, RT-PCR and western blot analyses. Scanning electron microscopy (SEM) and histology were used to detect cell-matrix interactions. DMEM/F12 supplemented by KGF and EGF induced EnSCs to express urothelial cell-specific genes and proteins. Either collagen, silk or silk-collagen scaffolds promoted cell proliferation. The nanofibrous silk-collagen scaffolds provided a three-dimensional (3D) structure to maximize cell-matrix penetration and increase differentiation of the EnSCs. Human EnSCs seeded on 3D nanofibrous silk-collagen scaffolds and differentiated to urothelial cells provide a suitable source for potential use in bladder wall reconstruction in women. Copyright © 2013 John Wiley & Sons, Ltd.

  3. Functionalized ormosil scaffolds processed by direct laser polymerization for application in tissue engineering

    DEFF Research Database (Denmark)

    Matei, A.; Schou, Jørgen; Canulescu, Stela

    2013-01-01

    Synthesized N,N′-(methacryloyloxyethyl triehtoxy silyl propyl carbamoyl-oxyhexyl)-urea hybrid methacrylate was polymerized by direct laser polymerization using femtosecond laser pulses with the aim of using it for subsequent applications in tissue engineering. The as-obtained scaffolds were...

  4. Potential applications of three-dimensional structure of silk fibroin/poly(ester-urethane) urea nanofibrous scaffold in heart valve tissue engineering

    Science.gov (United States)

    Du, Juan; Zhu, Tonghe; Yu, Haiyan; Zhu, Jingjing; Sun, Changbing; Wang, Jincheng; Chen, Sihao; Wang, Jihu; Guo, Xuran

    2018-07-01

    Tissue engineering heart valves (TEHV) are thought to have many advantages in low immunogenicity, good histocompatibility, excellent mechanical properties. In this paper, we reported the fabrication and characterization of a novel composite nanofibrous scaffold consisting of silk fibroin (SF) and poly(ester-urethane) urea (LDI-PEUU) by using electrospinning. Chemical and physical properties of scaffolds were evaluated using scanning electron microscopy, attenuated total reflectance Fourier transform infrared, X-ray diffraction, contact angle measurement, thermogravimetric analysis, biodegradation test and tensile strength analysis. We determined that the composite scaffolds supported the growth of human umbilical vein endothelial cell (HUVEC). The results of cell proliferation and cell morphology indicate that SF/LDI-PEUU nanofibers promoted cell viability, which supporting the application in tissue engineering. All results clarified that SF/LDI-PEUU (40:60) nanofibrous scaffolds meet the required specifications for tissue engineering and could be used as a promising construct for heart valve tissue engineering.

  5. Three-dimensional dynamic fabrication of engineered cartilage based on chitosan/gelatin hybrid hydrogel scaffold in a spinner flask with a special designed steel frame.

    Science.gov (United States)

    Song, Kedong; Li, Liying; Li, Wenfang; Zhu, Yanxia; Jiao, Zeren; Lim, Mayasari; Fang, Meiyun; Shi, Fangxin; Wang, Ling; Liu, Tianqing

    2015-10-01

    Cartilage transplantation using in vitro tissue engineered cartilage is considered a promising treatment for articular cartilage defects. In this study, we assessed the advantages of adipose derived stem cells (ADSCs) combined with chitosan/gelatin hybrid hydrogel scaffolds, which acted as a cartilage biomimetic scaffold, to fabricate a tissue engineered cartilage dynamically in vitro and compared this with traditional static culture. Physical properties of the hydrogel scaffolds were evaluated and ADSCs were inoculated into the hydrogel at a density of 1×10(7) cells/mL and cultured in a spinner flask with a special designed steel framework and feed with chondrogenic inductive media for two weeks. The results showed that the average pore size, porosity, swelling rate and elasticity modulus of hybrid scaffolds with good biocompatibility were 118.25±19.51 μm, 82.60±2.34%, 361.28±0.47% and 61.2±0.16 kPa, respectively. ADSCs grew well in chitosan/gelatin hybrid scaffold and successfully differentiated into chondrocytes, showing that the scaffolds were suitable for tissue engineering applications in cartilage regeneration. Induced cells cultivated in a dynamic spinner flask with a special designed steel frame expressed more proteoglycans and the cell distribution was much more uniform with the scaffold being filled mostly with extracellular matrix produced by cells. A spinner flask with framework promoted proliferation and chondrogenic differentiation of ADSCs within chitosan/gelatin hybrid scaffolds and accelerated dynamic fabrication of cell-hydrogel constructs, which could be a selective and good method to construct tissue engineered cartilage in vitro. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Addition of MgO nanoparticles and plasma surface treatment of three-dimensional printed polycaprolactone/hydroxyapatite scaffolds for improving bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hee-Sang; Lee, Chang-Min; Hwang, Young-Hyoun [Department of Dental Materials, School of Dentistry, Chosun University, Gwangju 61452 (Korea, Republic of); Kook, Min-Suk [Department of Oral & Maxillofacial Surgery, School of Dentistry, Chonnam National University, Gwangju 61186 (Korea, Republic of); Yang, Seong-Won [Department of Ophthalmology, College of Medicine, Chosun University, Gwangju 61452 (Korea, Republic of); Lee, Donghun [Department of Herbal Pharmacology, Kyung Hee University College of Korean Medicine, Seoul 130-701 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, Chosun University, Gwangju 61452 (Korea, Republic of)

    2017-05-01

    Magnesium (Mg) plays an important role in the body in mediating cell-extracellular matrix interactions and controlling bone apatite structure and density. Hydroxyapatite (HAp) has been used for osteoconductive bone replacement because of its good compressive strength and biocompatibility. The object of this study is to investigate the effects of adding Magnesium oxide (MgO) nanoparticles to polycaprolactone (PCL)/HAp composites and treating PCL/HAp/MgO scaffolds with oxygen and nitrogen plasma. The 3D PCL/HAp/MgO scaffolds were fabricated using a 3D bioextruder. PCL was mixed with 1–15 wt% of MgO and HAp. The scaffolds were treated with oxygen and nitrogen plasma under anisotropic etching conditions to improve the bioactivity. The plasma-treated surfaces were analyzed by X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. In addition, the proliferation and differentiation of pre-osteoblast (MC3T3-E1) cells were examined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and alkaline phosphatase activity. Cell mineralization within the produced scaffolds was analyzed by the quantification of alizarin stainings. The addition of MgO/HAp nanoparticles and plasma treatment enhanced the adhesion, proliferation, and differentiation of MC3T3-E1 cells in the PCL scaffolds. Hence, changes in physical surface morphology and surface chemical properties of the 3D scaffold by plasma treatment can affect the behavior of MC3T3-E1 cells. - Highlights: • 3D-printed PCL/HAp/MgO showed good porosity and interconnectivity. • O{sub 2} and N{sub 2} plasma improved the surface roughness and hydrophilicity on scaffolds. • Addition of HAp/MgO nanoparticles enhanced the cell behavior of preosteoblast.

  7. Three-dimensional dynamic fabrication of engineered cartilage based on chitosan/gelatin hybrid hydrogel scaffold in a spinner flask with a special designed steel frame

    International Nuclear Information System (INIS)

    Song, Kedong; Li, Liying; Li, Wenfang; Zhu, Yanxia; Jiao, Zeren; Lim, Mayasari; Fang, Meiyun; Shi, Fangxin; Wang, Ling; Liu, Tianqing

    2015-01-01

    Cartilage transplantation using in vitro tissue engineered cartilage is considered a promising treatment for articular cartilage defects. In this study, we assessed the advantages of adipose derived stem cells (ADSCs) combined with chitosan/gelatin hybrid hydrogel scaffolds, which acted as a cartilage biomimetic scaffold, to fabricate a tissue engineered cartilage dynamically in vitro and compared this with traditional static culture. Physical properties of the hydrogel scaffolds were evaluated and ADSCs were inoculated into the hydrogel at a density of 1 × 10 7 cells/mL and cultured in a spinner flask with a special designed steel framework and feed with chondrogenic inductive media for two weeks. The results showed that the average pore size, porosity, swelling rate and elasticity modulus of hybrid scaffolds with good biocompatibility were 118.25 ± 19.51 μm, 82.60 ± 2.34%, 361.28 ± 0.47% and 61.2 ± 0.16 kPa, respectively. ADSCs grew well in chitosan/gelatin hybrid scaffold and successfully differentiated into chondrocytes, showing that the scaffolds were suitable for tissue engineering applications in cartilage regeneration. Induced cells cultivated in a dynamic spinner flask with a special designed steel frame expressed more proteoglycans and the cell distribution was much more uniform with the scaffold being filled mostly with extracellular matrix produced by cells. A spinner flask with framework promoted proliferation and chondrogenic differentiation of ADSCs within chitosan/gelatin hybrid scaffolds and accelerated dynamic fabrication of cell–hydrogel constructs, which could be a selective and good method to construct tissue engineered cartilage in vitro. - Highlights: • ADSCs/hybrid scaffold constructs are dynamically fabricated in a spinner flask with a special framework. • Inside convection in spinner flask made enough supplement of oxygen and nutrients far beyond the depth of passive diffusion. • 3D culture environment accelerated mass

  8. Three-dimensional dynamic fabrication of engineered cartilage based on chitosan/gelatin hybrid hydrogel scaffold in a spinner flask with a special designed steel frame

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kedong, E-mail: kedongsong@dlut.edu.cn [State Key Laboratory of Fine Chemicals, Dalian R& D Center for Stem Cell and Tissue Engineering, Dalian University of Technology, Dalian 116024 (China); Li, Liying; Li, Wenfang [State Key Laboratory of Fine Chemicals, Dalian R& D Center for Stem Cell and Tissue Engineering, Dalian University of Technology, Dalian 116024 (China); Zhu, Yanxia [Anti-Ageing and Regenerative Medicine Centre, Shenzhen University, 3688 Nanhai Avenue, Shenzhen 518060 Guangdong (China); Jiao, Zeren [State Key Laboratory of Fine Chemicals, Dalian R& D Center for Stem Cell and Tissue Engineering, Dalian University of Technology, Dalian 116024 (China); Lim, Mayasari [Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Fang, Meiyun [Department of Hematology, First Affiliated Hospital, Dalian Medical University, Dalian 116011 (China); Shi, Fangxin [Department of Oncology, First Affiliated Hospital of Dalian Medical University, Dalian 116011 (China); Wang, Ling, E-mail: whwl@hotmail.com [Department of Obstetrics and Gynecology, First Affiliated Hospital, Dalian Medical University, Dalian 116011 (China); Liu, Tianqing, E-mail: liutq@dlut.edu.cn [State Key Laboratory of Fine Chemicals, Dalian R& D Center for Stem Cell and Tissue Engineering, Dalian University of Technology, Dalian 116024 (China)

    2015-10-01

    Cartilage transplantation using in vitro tissue engineered cartilage is considered a promising treatment for articular cartilage defects. In this study, we assessed the advantages of adipose derived stem cells (ADSCs) combined with chitosan/gelatin hybrid hydrogel scaffolds, which acted as a cartilage biomimetic scaffold, to fabricate a tissue engineered cartilage dynamically in vitro and compared this with traditional static culture. Physical properties of the hydrogel scaffolds were evaluated and ADSCs were inoculated into the hydrogel at a density of 1 × 10{sup 7} cells/mL and cultured in a spinner flask with a special designed steel framework and feed with chondrogenic inductive media for two weeks. The results showed that the average pore size, porosity, swelling rate and elasticity modulus of hybrid scaffolds with good biocompatibility were 118.25 ± 19.51 μm, 82.60 ± 2.34%, 361.28 ± 0.47% and 61.2 ± 0.16 kPa, respectively. ADSCs grew well in chitosan/gelatin hybrid scaffold and successfully differentiated into chondrocytes, showing that the scaffolds were suitable for tissue engineering applications in cartilage regeneration. Induced cells cultivated in a dynamic spinner flask with a special designed steel frame expressed more proteoglycans and the cell distribution was much more uniform with the scaffold being filled mostly with extracellular matrix produced by cells. A spinner flask with framework promoted proliferation and chondrogenic differentiation of ADSCs within chitosan/gelatin hybrid scaffolds and accelerated dynamic fabrication of cell–hydrogel constructs, which could be a selective and good method to construct tissue engineered cartilage in vitro. - Highlights: • ADSCs/hybrid scaffold constructs are dynamically fabricated in a spinner flask with a special framework. • Inside convection in spinner flask made enough supplement of oxygen and nutrients far beyond the depth of passive diffusion. • 3D culture environment accelerated mass

  9. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  10. Effects of chitosan-coated fibers as a scaffold for three-dimensional cultures of rabbit fibroblasts for ligament tissue engineering.

    Science.gov (United States)

    Sarukawa, Junichiro; Takahashi, Masaaki; Abe, Masashi; Suzuki, Daisuke; Tokura, Seiichi; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    Material selection in tissue-engineering scaffolds is one of the primary factors defining cellular response and matrix formation. In this study, we fabricated chitosan-coated poly(lactic acid) (PLA) fiber scaffolds to test our hypothesis that PLA fibers coated with chitosan highly promoted cell supporting properties compared to those without chitosan. Both PLA fibers (PLA group) and chitosan-coated PLA fibers (PLA-chitosan group) were fabricated for this study. Anterior cruciate ligament (ACL) fibroblasts were isolated from Japanese white rabbits and cultured on scaffolds consisting of each type of fiber. The effects of cell adhesivity, proliferation, and synthesis of the extracellular matrix (ECM) for each fiber were analyzed by cell counting, hydroxyproline assay, scanning electron microscopy and quantitative RT-PCR. Cell adhesivity, proliferation, hydroxyproline content and the expression of type-I collagen mRNA were significantly higher in the PLA-chitosan group than in the PLA group. Scanning electron microscopic observation showed that fibroblasts proliferated with a high level of ECM synthesis around the cells. Chitosan coating improved ACL fibroblast adhesion and proliferation, and had a positive effect on matrix production. Thus, the advantages of chitosan-coated PLA fibers show them to be a suitable biomaterial for ACL tissue-engineering scaffolds.

  11. Three-dimensional Printed Scaffolds with Gelatin and Platelets Enhance In vitro Preosteoblast Growth Behavior and the Sustained-release Effect of Growth Factors

    Directory of Open Access Journals (Sweden)

    Wei Zhu

    2016-01-01

    Conclusions: Our experiments confirmed that the 3D printed scaffolds we had designed could provide a sustained-release effect for growth factors and improve the proliferation of preosteoblasts with little cytotoxicity in vitro. They may hold promise as bone graft substitute materials in the future.

  12. Fabrication of Three Dimensional Tissue Engineering Polydimethylsiloxane ( PDMS) Microporous Scaffolds Integrated in a Bioreactor Using a 3D Printed Water Dissolvable Sacrificial Mould

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan; Mantis, Ioannis; Chetan, Aradhya Mallikarjunaiah

    2015-01-01

    We present a new scalable and general approach for manufacturing structured pores/channels in 3D polymer based scaffolds. The method involves 3D printing of a sacrificial polyvinyl alcohol (PVA) mould whose geometrical features are designed according to the required vascular channel network. Poly...

  13. Image-based characterization of foamed polymeric tissue scaffolds

    International Nuclear Information System (INIS)

    Mather, Melissa L; Morgan, Stephen P; Crowe, John A; White, Lisa J; Shakesheff, Kevin M; Tai, Hongyun; Howdle, Steven M; Kockenberger, Walter

    2008-01-01

    Tissue scaffolds are integral to many regenerative medicine therapies, providing suitable environments for tissue regeneration. In order to assess their suitability, methods to routinely and reproducibly characterize scaffolds are needed. Scaffold structures are typically complex, and thus their characterization is far from trivial. The work presented in this paper is centred on the application of the principles of scaffold characterization outlined in guidelines developed by ASTM International. Specifically, this work demonstrates the capabilities of different imaging modalities and analysis techniques used to characterize scaffolds fabricated from poly(lactic-co-glycolic acid) using supercritical carbon dioxide. Three structurally different scaffolds were used. The scaffolds were imaged using: scanning electron microscopy, micro x-ray computed tomography, magnetic resonance imaging and terahertz pulsed imaging. In each case two-dimensional images were obtained from which scaffold properties were determined using image processing. The findings of this work highlight how the chosen imaging modality and image-processing technique can influence the results of scaffold characterization. It is concluded that in order to obtain useful results from image-based scaffold characterization, an imaging methodology providing sufficient contrast and resolution must be used along with robust image segmentation methods to allow intercomparison of results

  14. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.; Aldhahri, Musab A.; Abdel-wahab, Mohamed Shaaban; Tamayol, Ali; Moghaddam, K. Mollazadeh; Ben Rached, Fathia; Pain, Arnab; Khademhosseini, Ali; Memic, Adnan; Chaieb, Saharoui

    2017-01-01

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  15. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.

    2017-07-07

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  16. Platelet-functionalized three-dimensional polye-epsilon-caprolactone fibrous scaffold prepared using centrifugal spinning for delivery of growth factors

    Czech Academy of Sciences Publication Activity Database

    Rampichová, Michala; Buzgo, M.; Míčková, Andrea; Vocetková, Karolína; Sovková, Věra; Lukášová, Věra; Filová, Eva; Rustichelli, Franco; Amler, Evžen

    2017-01-01

    Roč. 12, č. 2017 (2017), s. 347-361 E-ISSN 1178-2013 R&D Projects: GA ČR(CZ) GA15-15697S; GA MŠk(CZ) LO1508 Institutional support: RVO:68378041 Keywords : centrifugal spinning * 3D scaffold * platelets Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Nano-materials (production and properties) Impact factor: 4.300, year: 2016

  17. Amorphous hydroxyapatite-sintered polymeric scaffolds for bone tissue regeneration: physical characterization studies.

    Science.gov (United States)

    Cushnie, Emily K; Khan, Yusuf M; Laurencin, Cato T

    2008-01-01

    Given the inherent shortcomings of autografts and allografts, donor-site morbidity and risk of disease transmission, respectively, alternatives to traditional bone grafting options are warranted. To this end, poly(lactide-co-glycolide) (PLAGA) and in situ-synthesized amorphous hydroxyapatite (HA) were used to construct three-dimensional microsphere-based composite scaffolds of varying HA content for bone regeneration. In the current study, the effect of adding amorphous HA to the PLAGA scaffolds on their physical characteristics and in vitro degradation mechanism was investigated. Porosimetry and uniaxial compression testing were used to analyze the internal structure and elastic modulus of the scaffolds, respectively. Additionally, gel permeation chromatography (GPC) was performed to assess the polymer molecular weight over the course of an 8-week degradation study. HA content (17% or 27%) of the composite scaffolds was found to increase scaffold pore volume from 33.86% for pure polymer scaffolds, to 40.49% or 46.29%, depending on the amount of incorporated HA. This increased pore volume provided the composite scaffolds with a greater surface area and a corresponding decrease in elastic modulus. Scaffold degradation studies conducted over 8 weeks showed PLAGA to degrade in a first-order mechanism, with the rate of polymer degradation for the 27% HA composite scaffold being significantly slower than that of the pure PLAGA scaffold (degradation constants of 0.0324 and 0.0232 week(-1), respectively). These results suggest that the addition of amorphous HA to PLAGA microspheres resulted in porous, bioactive scaffolds that offer potential as alternative bone grafting materials for the field of regenerative medicine. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

  18. Peracetic Acid: A Practical Agent for Sterilizing Heat-Labile Polymeric Tissue-Engineering Scaffolds

    Science.gov (United States)

    Yoganarasimha, Suyog; Trahan, William R.; Best, Al M.; Bowlin, Gary L.; Kitten, Todd O.; Moon, Peter C.

    2014-01-01

    Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000 ppm or above sterilized electrospun scaffolds in 15 min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000 ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering. PMID:24341350

  19. PHBV/PAM scaffolds with local oriented structure through UV polymerization for tissue engineering.

    Science.gov (United States)

    Ke, Yu; Wu, Gang; Wang, Yingjun

    2014-01-01

    Locally oriented tissue engineering scaffolds can provoke cellular orientation and direct cell spread and migration, offering an exciting potential way for the regeneration of the complex tissue. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds with locally oriented hydrophilic polyacrylamide (PAM) inside the macropores of the scaffolds were achieved through UV graft polymerization. The interpenetrating PAM chains enabled good interconnectivity of PHBV/PAM scaffolds that presented a lower porosity and minor diameter of pores than PHBV scaffolds. The pores with diameter below 100  μm increased to 82.15% of PHBV/PAM scaffolds compared with 31.5% of PHBV scaffolds. PHBV/PAM scaffold showed a much higher compressive elastic modulus than PHBV scaffold due to PAM stuffing. At 5 days of culturing, sheep chondrocytes spread along the similar direction in the macropores of PHBV/PAM scaffolds. The locally oriented PAM chains might guide the attachment and spreading of chondrocytes and direct the formation of microfilaments via contact guidance.

  20. Three-Dimensional Bio-Printed Scaffold Sleeves With Mesenchymal Stem Cells for Enhancement of Tendon-to-Bone Healing in Anterior Cruciate Ligament Reconstruction Using Soft-Tissue Tendon Graft.

    Science.gov (United States)

    Park, Sin Hyung; Choi, Yeong-Jin; Moon, Sang Won; Lee, Byung Hoon; Shim, Jin-Hyung; Cho, Dong-Woo; Wang, Joon Ho

    2018-01-01

    To investigate the efficacy of the insertion of 3-dimensional (3D) bio-printed scaffold sleeves seeded with mesenchymal stem cells (MSCs) to enhance osteointegration between the tendon and tunnel bone in anterior cruciate ligament (ACL) reconstruction in a rabbit model. Scaffold sleeves were fabricated by 3D bio-printing. Before ACL reconstruction, MSCs were seeded into the scaffold sleeves. ACL reconstruction with hamstring tendon was performed on both legs of 15 adult rabbits (aged 12 weeks). We implanted 15 bone tunnels with scaffold sleeves with MSCs and implanted another 15 bone tunnels with scaffold sleeves without MSCs before passing the graft. The specimens were harvested at 4, 8, and 12 weeks. H&E staining, immunohistochemical staining of type II collagen, and micro-computed tomography of the tunnel cross-sectional area were evaluated. Histologic assessment was conducted with a histologic scoring system. In the histologic assessment, a smooth bone-to-tendon transition through broad fibrocartilage formation was identified in the treatment group, and the interface zone showed abundant type II collagen production on immunohistochemical staining. Bone-tendon healing histologic scores were significantly higher in the treatment group than in the control group at all time points. Micro-computed tomography at 12 weeks showed smaller tibial (control, 9.4 ± 0.9 mm 2 ; treatment, 5.8 ± 2.9 mm 2 ; P = .044) and femoral (control, 9.6 ± 2.9 mm 2 ; treatment, 6.0 ± 1.0 mm 2 ; P = .03) bone-tunnel areas in the treated group than in the control group. The 3D bio-printed scaffold sleeve with MSCs exhibited excellent results in osteointegration enhancement between the tendon and tunnel bone in ACL reconstruction in a rabbit model. If secure biological healing between the tendon graft and tunnel bone can be induced in the early postoperative period, earlier, more successful rehabilitation may be facilitated. Three-dimensional bio-printed scaffold sleeves with

  1. Methods of Monitoring Cell Fate and Tissue Growth in Three-Dimensional Scaffold-Based Strategies for In Vitro Tissue Engineering.

    Science.gov (United States)

    Leferink, Anne M; van Blitterswijk, Clemens A; Moroni, Lorenzo

    2016-08-01

    In the field of tissue engineering, there is a need for methods that allow assessing the performance of tissue-engineered constructs noninvasively in vitro and in vivo. To date, histological analysis is the golden standard to retrieve information on tissue growth, cellular distribution, and cell fate on tissue-engineered constructs after in vitro cell culture or on explanted specimens after in vivo applications. Yet, many advances have been made to optimize imaging techniques for monitoring tissue-engineered constructs with a sub-mm or μm resolution. Many imaging modalities have first been developed for clinical applications, in which a high penetration depth has been often more important than lateral resolution. In this study, we have reviewed the current state of the art in several imaging approaches that have shown to be promising in monitoring cell fate and tissue growth upon in vitro culture. Depending on the aimed tissue type and scaffold properties, some imaging methods are more applicable than others. Optical methods are mostly suited for transparent materials such as hydrogels, whereas magnetic resonance-based methods are mostly applied to obtain contrast between hard and soft tissues regardless of their transparency. Overall, this review shows that the field of imaging in scaffold-based tissue engineering is developing at a fast pace and has the potential to overcome the limitations of destructive endpoint analysis.

  2. Imaging of cellular spread on a three-dimensional scaffold by means of a novel cell-labeling technique for high-resolution computed tomography.

    Science.gov (United States)

    Thimm, Benjamin W; Hofmann, Sandra; Schneider, Philipp; Carretta, Roberto; Müller, Ralph

    2012-03-01

    Computed tomography (CT) represents a truly three-dimensional (3D) imaging technique that can provide high-resolution images on the cellular level. Thus, one approach to detect single cells is X-ray absorption-based CT, where cells are labeled with a dense, opaque material providing the required contrast for CT imaging. Within the present work, a novel cell-labeling method has been developed showing the feasibility of labeling fixed cells with iron oxide (FeO) particles for subsequent CT imaging and quantitative morphometry. A biotin-streptavidin detection system was exploited to bind FeO particles to its target endothelial cells. The binding of the particles was predominantly close to the cell centers on 2D surfaces as shown by light microscopy, scanning electron microscopy, and CT. When cells were cultured on porous, 3D polyurethane surfaces, significantly more FeO particles were detected compared with surfaces without cells and FeO particle labeling using CT. Here, we report on the implementation and evaluation of a novel cell detection method based on high-resolution CT. This system has potential in cell tracking for 3D in vitro imaging in the future.

  3. An improved polymeric sponge replication method for biomedical porous titanium scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunli; Chen, Hongjie; Zhu, Xiangdong, E-mail: zxd7303@163.com; Xiao, Zhanwen; Zhang, Kai, E-mail: kaizhang@scu.edu.cn; Zhang, Xingdong

    2017-01-01

    Biomedical porous titanium (Ti) scaffolds were fabricated by an improved polymeric sponge replication method. The unique formulations and distinct processing techniques, i.e. a mixture of water and ethanol as solvent, multiple coatings with different viscosities of the Ti slurries and centrifugation for removing the extra slurries were used in the present study. The optimized porous Ti scaffolds had uniform porous structure and completely interconnected macropores (~ 365.1 μm). In addition, two different sizes of micropores (~ 45.4 and ~ 6.2 μm) were also formed in the skeleton of the scaffold. The addition of ethanol to the Ti slurry increased the compressive strength of the scaffold by improving the compactness of the skeleton. A compressive strength of 83.6 ± 4.0 MPa was achieved for a porous Ti scaffold with a porosity of 66.4 ± 1.8%. Our cellular study also revealed that the scaffolds could support the growth and proliferation of mesenchymal stem cells (MSCs). - Highlights: • An improved sponge replication method for porous titanium scaffolds was developed. • A mixture of water and ethanol was used to make the titanium slurries. • The scaffolds have high mechanical strength for load-bearing bone repair. • The scaffolds support growth of mesenchymal stem cells.

  4. A study of a three-dimensional PLGA sponge containing natural polymers co-cultured with endothelial and mesenchymal stem cells as a tissue engineering scaffold

    International Nuclear Information System (INIS)

    Shim, Jung Bo; Kim, Hyeongseok; Khang, Gilson; Ankeny, Randall F; Nerem, Robert M

    2014-01-01

    The interaction between vascular endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in a complex hemodynamic and mechanical environment plays an important role in the control of blood vessel growth and function. Despite the importance of VSMCs, substitutes are needed for vascular therapies. A potential VSMC substitute is human adult bone marrow derived mesenchymal stem cells (hMSCs). In this study, the effect of poly(lactic-co-glycolic acid) (PLGA) scaffolds containing three natural polymers (demineralized bone particles, silk, and small intestine submucosa) on the phenotype of MSCs and SMCs cultured with or without ECs was investigated. The study objective was to create a media equivalent for a tissue engineered blood vessel using PLGA, natural polymers, and MSCs co-cultured with ECs. The PLGA containing the natural polymers silk and SIS showed increased proliferation and cell adhesion. The presence of silk and DBP promoted a MSC phenotype change into a SMC-like phenotype at the mRNA level; however these differences at the protein level were not seen. Additionally, PLGA containing SIS did not induce SMC gene or protein upregulation. Finally, the effect of ECs in combination with the natural polymers was tested. When co-cultured with ECs, the mRNA of SMC specific markers in MSCs and SMCs were increased when compared to SMCs or MSCs alone. However, MSCs, when co-cultured with ECs on PLGA containing silk, exhibited significantly increased α-SMA and calponin expression when compared to PLGA only scaffolds. These results indicate that the natural polymer silk in combination with the co-culture of endothelial cells was most effective at increasing cell viability and inducing a SMC-like phenotype at the mRNA and protein level in MSCs. (paper)

  5. Three-dimensional simulated microgravity culture improves the proliferation and odontogenic differentiation of dental pulp stem cell in PLGA scaffolds implanted in mice.

    Science.gov (United States)

    Li, Yanping; He, Lina; Pan, Shuang; Zhang, Lin; Zhang, Weiwei; Yi, Hong; Niu, Yumei

    2017-02-01

    Tooth regeneration through stem cell-based therapy is a promising treatment for tooth decay and loss. Human dental pulp stem cells (hDPSCs) have been widely identified as the stem cells with the most potential for tooth tissue regeneration. However, the culture of hDPSCs in vitro for tissue engineering is challenging, as cells may proliferate slowly or/and differentiate poorly in vivo. Dynamic three‑dimensional (3D) simulated microgravity (SMG) created using the rotary cell culture system is considered to an effective tool, which contributes to several cell functions. Thus, the present study aimed to investigate the effect of dynamic 3D SMG culture on the proliferation and odontogenic differentiation abilities of hDPSCs in poly (lactic‑co‑glycolic acid) (PLGA) scaffolds in nude mice. The hDPSCs on PLGA scaffolds were maintained separately in the 3D SMG culture system and static 3D cultures with osteogenic medium for 7 days in vitro. Subsequently, the cell‑PLGA complexes were implanted subcutaneously on the backs of nude mice for 4 weeks. The results of histological and immunohistochemical examinations of Ki‑67, type I collagen, dentin sialoprotein and DMP‑1 indicated that the proliferation and odontogenic differentiation abilities of the hDPSCs prepared in the 3D SMG culture system were higher, compared with those prepared in the static culture system. These findings suggested that dynamic 3D SMG culture likely contributes to tissue engineering by improving the proliferation and odontogenic differentiation abilities of hDPSCs in vivo.

  6. Three dimensional canonical transformations

    International Nuclear Information System (INIS)

    Tegmen, A.

    2010-01-01

    A generic construction of canonical transformations is given in three-dimensional phase spaces on which Nambu bracket is imposed. First, the canonical transformations are defined as based on cannonade transformations. Second, it is shown that determination of the generating functions and the transformation itself for given generating function is possible by solving correspondent Pfaffian differential equations. Generating functions of type are introduced and all of them are listed. Infinitesimal canonical transformations are also discussed as the complementary subject. Finally, it is shown that decomposition of canonical transformations is also possible in three-dimensional phase spaces as in the usual two-dimensional ones.

  7. Three-dimensional neuroimaging

    International Nuclear Information System (INIS)

    Toga, A.W.

    1990-01-01

    This book reports on new neuroimaging technologies that are revolutionizing the study of the brain be enabling investigators to visualize its structure and entire pattern of functional activity in three dimensions. The book provides a theoretical and practical explanation of the new science of creating three-dimensional computer images of the brain. The coverage includes a review of the technology and methodology of neuroimaging, the instrumentation and procedures, issues of quantification, analytic protocols, and descriptions of neuroimaging systems. Examples are given to illustrate the use of three-dimensional enuroimaging to quantitate spatial measurements, perform analysis of autoradiographic and histological studies, and study the relationship between brain structure and function

  8. Three-dimensional wet-electrospun poly(lactic acid)/multi-wall carbon nanotubes scaffold induces differentiation of human menstrual blood-derived stem cells into germ-like cells.

    Science.gov (United States)

    Eyni, Hossein; Ghorbani, Sadegh; Shirazi, Reza; Salari Asl, Leila; P Beiranvand, Shahram; Soleimani, Masoud

    2017-09-01

    Infertility caused by the disruption or absence of germ cells is a major and largely incurable medical problem. Germ cells (i.e., sperm or egg) play a key role in the transmission of genetic and epigenetic information across generations. Generation of gametes derived in vitro from stem cells hold promising prospects which could potentially help infertile men and women. Menstrual blood-derived stem cells are a unique stem cell source. Evidence suggests that menstrual blood-derived stem cells exhibit a multi-lineage potential and have attracted extensive attention in regenerative medicine. To maintain the three-dimensional structure of natural extra cellular matrices in vitro, scaffolds can do this favor and mimic a microenvironment for cell proliferation and differentiation. According to previous studies, poly(lactic acid) and multi-wall carbon nanotubes have been introduced as novel and promising biomaterials for the proliferation and differentiation of stem cells. Some cell types have been successfully grown on a matrix containing carbon nanotubes in tissue engineering but there is no report for this material to support stem cells differentiation into germ cells lineage. This study designed a 3D wet-electrospun poly(lactic acid) and poly(lactic acid)/multi-wall carbon nanotubes composite scaffold to compare infiltration, proliferation, and differentiation potential of menstrual blood-derived stem cells toward germ cell lineage with 2D culture. Our primary data revealed that the fabricated scaffold has mechanical and biological suitable qualities for supporting and attachments of stem cells. The differentiated menstrual blood-derived stem cells tracking in scaffolds using scanning electron microscopy confirmed cell attachment, aggregation, and distribution on the porous scaffold. Based on the differentiation assay by RT-PCR analysis, stem cells and germ-like cells markers were expressed in 3D groups as well as 2D one. It seems that poly(lactic acid

  9. The Role of Three-Dimensional Scaffolds in Treating Long Bone Defects: Evidence from Preclinical and Clinical Literature-A Systematic Review.

    Science.gov (United States)

    Roffi, Alice; Krishnakumar, Gopal Shankar; Gostynska, Natalia; Kon, Elizaveta; Candrian, Christian; Filardo, Giuseppe

    2017-01-01

    Long bone defects represent a clinical challenge. Bone tissue engineering (BTE) has been developed to overcome problems associated with conventional methods. The aim of this study was to assess the BTE strategies available in preclinical and clinical settings and the current evidence supporting this approach. A systematic literature screening was performed on PubMed database, searching for both preclinical (only on large animals) and clinical studies. The following string was used: "(Scaffold OR Implant) AND (Long bone defect OR segmental bone defect OR large bone defect OR bone loss defect)." The search retrieved a total of 1573 articles: 51 preclinical and 4 clinical studies were included. The great amount of preclinical papers published over the past few years showed promising findings in terms of radiological and histological evidence. Unfortunately, this in vivo situation is not reflected by a corresponding clinical impact, with few published papers, highly heterogeneous and with small patient populations. Several aspects should be further investigated to translate positive preclinical findings into clinical protocols: the identification of the best biomaterial, with both biological and biomechanical suitable properties, and the selection of the best choice between cells, GFs, or their combination through standardized models to be validated by randomized trials.

  10. Three dimensional MEMS supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei

    2011-10-15

    The overall objective of this research is to achieve compact supercapacitors with high capacitance, large power density, and long cycle life for using as micro power sources to drive low power devices and sensors. The main shortcoming of supercapacitors as a power source is that its energy density typically is about 1/10 of that of batteries. To achieve compact supercapacitors of large energy density, supercapacitors must be developed with high capacitance and power density which are mainly depended on the effective surface area of the electrodes of the supercapacitors. Many studies have been done to increase the effective surface area by modifying the electrode materials, however, much less investigations are focus on machining the electrodes. In my thesis work, micro- and nano-technologies are applied as technology approaches for machining the electrodes with three dimensional (3D) microstructures. More specific, Micro-electro-mechanical system (MEMS) fabrication process flow, which integrates the key process such as LIGA-like (German acronym for Lithographie, Galvanoformung, Abformung, which mean Lithography, Electroplating and Molding) technology or DRIE (deep reactive ion etching), has been developed to enable innovative designs of 3D MEMS supercapacitors which own the electrodes of significantly increased geometric area. Two types of 3D MEMS supercapcitors, based on LIGA-like and DRIE technology respectively, were designed and successfully created. The LIGA-like based 3D MEMS supercapacitor is with an interdigital 3D structure, and consists of silicon substrate, two electroplated nickel current collectors, two PPy (poly pyrrole) electrodes, and solid state electrolyte. The fabrication process flow developed includes the flowing key processes, SU-8 lithography, nickel electroplating, PPy polymerization and solid state electrolyte coating. Electrochemical tests showed that the single electrode of the supercapacitor has the specific capacitance of 0.058 F cm-2

  11. Processing parameters investigation for the fabrication of self-supported and freeform polymeric microstructures using ultraviolet-assisted three-dimensional printing

    International Nuclear Information System (INIS)

    Farahani, R D; Lebel, L L; Therriault, D

    2014-01-01

    Ultraviolet-assisted three-dimensional (3D) printing (UV-3DP) was used to manufacture photopolymer-based microdevices with 3D self-supported and freeform features. The UV-3DP technique consists of the robotized deposition of extruded filaments, which are rapidly photopolymerized under UV illumination during the deposition process. This paper systematically studies the processing parameters of the UV-3DP technique using two photo-curable polymers and their associated nanocomposite materials. The main processing parameters including materials' rheological behavior, deposition speed and extrusion pressure, and UV illumination conditions were thoroughly investigated. A processing map was then defined in order to help choosing the proper parameters for the UV-3DP of microstructures with various geometries. Compared to self-supported features, the accurate fabrication of 3D freeform structures was found to take place in a narrower processing region since a higher rigidity of the extruded filament was required for structural stability. Finally, various 3D self-supported and freeform microstructures with high potential in micro electromechanical systems, micro-systems and organic electronics were fabricated to show the capability of the technique. (paper)

  12. Impregnation of β-tricalcium phosphate robocast scaffolds by in situ polymerization.

    Science.gov (United States)

    Martínez-Vázquez, Francisco J; Perera, Fidel H; van der Meulen, Inge; Heise, Andreas; Pajares, Antonia; Miranda, Pedro

    2013-11-01

    Ring-opening polymerization of ε-caprolactone (ε-CL) and L-lactide (LLA) was performed to impregnate β-tricalcium phosphate (β-TCP) scaffolds fabricated by robocasting. Concentrated colloidal inks prepared from β-TCP commercial powders were used to fabricate porous structures consisting of a 3D mesh of interpenetrating rods. ε-CL and LLA were in situ polymerized within the ceramic structure by using a lipase and stannous octanoate, respectively, as catalysts. The results show that both the macropores inside the ceramic mesh and the micropores within the ceramic rods are full of polymer in either case. The mechanical properties of scaffolds impregnated by in situ polymerization (ISP) are significantly increased over those of the bare structures, exhibiting similar values than those obtained by other, more aggressive, impregnation methods such as melt-immersion (MI). ISP using enzymatic catalysts requires a reduced processing temperature which could facilitate the incorporation of growth factors and other drugs into the polymer composition, thus enhancing the bioactivity of the composite scaffold. The implications of these results for the optimization of the mechanical and biological performance of scaffolds for bone tissue engineering applications are discussed. Copyright © 2013 Wiley Periodicals, Inc.

  13. Microporous polymeric 3D scaffolds templated by the layer-by-layer self-assembly.

    Science.gov (United States)

    Paulraj, Thomas; Feoktistova, Natalia; Velk, Natalia; Uhlig, Katja; Duschl, Claus; Volodkin, Dmitry

    2014-08-01

    Polymeric scaffolds serve as valuable supports for biological cells since they offer essential features for guiding cellular organization and tissue development. The main challenges for scaffold fabrication are i) to tune an internal structure and ii) to load bio-molecules such as growth factors and control their local concentration and distribution. Here, a new approach for the design of hollow polymeric scaffolds using porous CaCO3 particles (cores) as templates is presented. The cores packed into a microfluidic channel are coated with polymers employing the layer-by-layer (LbL) technique. Subsequent core elimination at mild conditions results in formation of the scaffold composed of interconnected hollow polymer microspheres. The size of the cores determines the feature dimensions and, as a consequence, governs cellular adhesion: for 3T3 fibroblasts an optimal microsphere size is 12 μm. By making use of the carrier properties of the porous CaCO3 cores, the microspheres are loaded with BSA as a model protein. The scaffolds developed here may also be well suited for the localized release of bio-molecules using external triggers such as IR-light. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Three-Dimensional Flows

    CERN Document Server

    Araujo, Vitor; Viana, Marcelo

    2010-01-01

    In this book, the authors present the elements of a general theory for flows on three-dimensional compact boundaryless manifolds, encompassing flows with equilibria accumulated by regular orbits. The book aims to provide a global perspective of this theory and make it easier for the reader to digest the growing literature on this subject. This is not the first book on the subject of dynamical systems, but there are distinct aspects which together make this book unique. Firstly, this book treats mostly continuous time dynamical systems, instead of its discrete counterpart, exhaustively treated

  15. Three dimensional system integration

    CERN Document Server

    Papanikolaou, Antonis; Radojcic, Riko

    2010-01-01

    Three-dimensional (3D) integrated circuit (IC) stacking is the next big step in electronic system integration. It enables packing more functionality, as well as integration of heterogeneous materials, devices, and signals, in the same space (volume). This results in consumer electronics (e.g., mobile, handheld devices) which can run more powerful applications, such as full-length movies and 3D games, with longer battery life. This technology is so promising that it is expected to be a mainstream technology a few years from now, less than 10-15 years from its original conception. To achieve thi

  16. Functionalized Ormosil Scaffolds Processed by Direct Laser Polymerization for Application in Tissue Engineering

    DEFF Research Database (Denmark)

    Matei, A.; Schou, Jørgen; Canulescu, Stela

    The N,N’-(methacryloyloxyethyl triehtoxy silyl propyl carbamoyl-oxyhexyl)-urea hybrid methacrylate for applications in tissue engineering was synthesized and afterwards polymerized by direct laser polymerization using femtosecond laser pulses with the aim of using it for further applications...... in tissue engineering. The as-obtained scaffolds were modified either by low pressure argon plasma treatment or by using two different proteins (lysozyme, fibrinogen). For improved adhesion, the proteins were deposited by matrix assisted pulsed laser evaporation. The functionalized structures were tested...

  17. Three Dimensional Dirac Semimetals

    Science.gov (United States)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  18. Antibacterial Capability, Physicochemical Properties, and Biocompatibility of nTiO2 Incorporated Polymeric Scaffolds

    Directory of Open Access Journals (Sweden)

    Cijun Shuai

    2018-03-01

    Full Text Available Postoperative infection is a common risk which brings about failure in bone transplantation. In this study, nano titanium dioxide (nTiO2 was incorporated into Polyetheretherketone/polyglycolicacid (PEEK/PGA blends to construct antibacterial scaffolds via selective laser sintering. Antibacterial capability was assessed using Escherichia coli (E. coli and Staphylococcus aureus (S. aureus. The results demonstrated that the scaffolds with nTiO2 presented an effective antibacterial activity, which might be attributed to that nTiO2 would do the mechanical and oxidative damage to bacteria by occurring contact actions and generating reactive oxygen species (ROS, and thus killed bacteria from structure and function. Moreover, nTiO2 could enhance the tensile strength and modulus of scaffolds due to the reinforcing effect and its uniform disperse. And the cell culture experiments showed that nTiO2 stimulated cellular attachment and proliferation. Besides, it also elevated the hydrophily and thermal stability of scaffolds. These results suggested that the polymeric scaffolds incorporated nTiO2 had potential application in bone tissue engineering.

  19. Three dimensional energy profile:

    International Nuclear Information System (INIS)

    Kowsari, Reza; Zerriffi, Hisham

    2011-01-01

    The provision of adequate, reliable, and affordable energy has been considered as a cornerstone of development. More than one-third of the world's population has a very limited access to modern energy services and suffers from its various negative consequences. Researchers have been exploring various dimensions of household energy use in order to design strategies to provide secure access to modern energy services. However, despite more than three decades of effort, our understanding of household energy use patterns is very limited, particularly in the context of rural regions of the developing world. Through this paper, the past and the current trends in the field of energy analysis are investigated. The literature on rural energy and energy transition in developing world has been explored and the factors affecting households' decisions on energy use are listed. The and the factors affecting households' decisions on energy use are listed. The gaps identified in the literature on rural household energy analysis provide a basis for developing an alternative model that can create a more realistic view of household energy use. The three dimensional energy profile is presented as a new conceptual model for assessment of household energy use. This framework acts as a basis for building new theoretical and empirical models of rural household energy use. - Highlights: ► Reviews literature on household energy, energy transitions and decision-making in developing countries. ► Identifies gaps in rural household energy analysis and develops a new conceptual framework. ► The 3-d energy profile provides a holistic view of household energy system characteristics. ► Illustrates the use of the framework for understanding household energy transitions.

  20. Three-dimensional echocardiography

    International Nuclear Information System (INIS)

    Buck, Thomas

    2011-01-01

    Presents tips and tricks for beginners and experts Provides educational material for 3D training courses Features comprehensively illustrated cases Includes an accompanying DVD with video clips of all sample cases Three-dimensional echocardiography is the most recent fundamental advancement in echocardiography. Since real-time 3D echocardiography became commercially available in 2002, it has rapidly been accepted in echo labs worldwide. This book covers all clinically relevant aspects of this fascinating new technology, including a comprehensive explanation of its basic principles, practical aspects of clinical application, and detailed descriptions of specific uses in the broad spectrum of clinically important heart disease. The book was written by a group of well-recognized international experts in the field, who have not only been involved in the scientific and clinical evolution of 3D echocardiography since its inception but are also intensively involved in expert training courses. As a result, the clear focus of this book is on the practical application of 3D echocardiography in daily clinical routine with tips and tricks for both beginners and experts, accompanied by more than 150 case examples comprehensively illustrated in more than 800 images and more than 500 videos provided on a DVD. In addition to an in-depth review of the most recent literature on real-time 3D echocardiography, this book represents an invaluable reference work for beginners and expert users of 3D echocardiography. - Tips and tricks for beginners and experts - Educational material for 3D training courses - Comprehensively illustrated cases - DVD with video clips of all sample cases.

  1. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2005-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  2. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2004-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  3. Sustained delivery of plasmid DNA from polymeric scaffolds for tissue engineering.

    Science.gov (United States)

    Storrie, Hannah; Mooney, David J

    2006-07-07

    The encapsulation of DNA into polymeric depot systems can be used to spatially and temporally control DNA release, leading to a sustained, local delivery of therapeutic factors for tissue regeneration. Prior to encapsulation, DNA may be condensed with cationic polymers to decrease particle size, protect DNA from degradation, promote interaction with cell membranes, and facilitate endosomal release via the proton sponge effect. DNA has been encapsulated with either natural or synthetic polymers to form micro- and nanospheres, porous scaffolds and hydrogels for sustained DNA release and the polymer physical and chemical properties have been shown to influence transfection efficiency. Polymeric depot systems have been applied for bone, skin, and nerve regeneration as well as therapeutic angiogenesis, indicating the broad applicability of these systems for tissue engineering.

  4. Physicochemical properties and enhanced cellullar responses of biocompatible polymeric scaffolds treated with atmospheric pressure plasma using O2 gas

    International Nuclear Information System (INIS)

    Lee, Hyun-Uk; Park, So-Young; Kang, Yoon-Hee; Jeong, Se-Young; Choi, Sae-Hae; Jahng, Yoon-Young; Chung, Gook-Hyun; Kim, Moon-Bum; Cho, Chae-Ryong

    2011-01-01

    Biocompatible polymeric scaffolds were fabricated by mixing 5 wt.% poly(ε-caprolactone) (P) with 4 wt.% gelatin (G) and 1.6 wt.% Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (D). These PGD scaffolds were also treated with atmospheric pressure (AP) plasma using O 2 reactive gas (to create O-PGD scaffolds). The physicochemical and mechanical properties of the PGD scaffolds were characterized by in vitro biodegradability tests, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, and tensile strength measurements. The wettability and hydrophilic properties of the scaffold surface were improved remarkably by adding G and D to P, and by subsequent oxygen-assisted AP plasma treatment. An MTT assay, a cell attachment efficiency assay, scanning electron microscopy, and confocal microscopy revealed that Chinese Hamster Ovary (CHO)-K1 cells exhibited higher cell attachment and viability on the PGD and O-PGD scaffolds than on the P and PG scaffolds. Furthermore, the long-term viability of the CHO cells on the PGD and O-PGD scaffolds without exchanging the cell culture media was significantly improved compared to their viability on the P and PG scaffolds. Overall, the PGD and O-PGD scaffolds are expected to be useful as cell growth supporting biomaterials in tissue engineering.

  5. Optimization of Polymer-ECM Composite Scaffolds for Tissue Engineering: Effect of Cells and Culture Conditions on Polymeric Nanofiber Mats

    Directory of Open Access Journals (Sweden)

    Ritu Goyal

    2017-01-01

    Full Text Available The design of composite tissue scaffolds containing an extracellular matrix (ECM and synthetic polymer fibers is a new approach to create bioactive scaffolds that can enhance cell function. Currently, studies investigating the effects of ECM-deposition and decellularization on polymer degradation are still lacking, as are data on optimizing the stability of the ECM-containing composite scaffolds during prolonged cell culture. In this study, we develop fibrous scaffolds using three polymer compositions, representing slow (E0000, medium (E0500, and fast (E1000 degrading materials, to investigate the stability, degradation, and mechanics of the scaffolds during ECM deposition and decellularization, and during the complete cellularization-decell-recell cycle. We report data on percent molecular weight (% Mw retention of polymeric fiber mats, changes in scaffold stiffness, ECM deposition, and the presence of fibronectin after decellularization. We concluded that the fast degrading E1000 (Mw retention ≤ 50% after 28 days was not sufficiently stable to allow scaffold handling after 28 days in culture, while the slow degradation of E0000 (Mw retention ≥ 80% in 28 days did not allow deposited ECM to replace the polymer support. The scaffolds made from medium degrading E0500 (Mw retention about 60% at 28 days allowed the gradual replacement of the polymer network with cell-derived ECM while maintaining the polymer network support. Thus, polymers with an intermediate rate of degradation, maintaining good scaffold handling properties after 28 days in culture, seem best suited for creating ECM-polymer composite scaffolds.

  6. Evaluation of polyelectrolyte complex-based scaffolds for mesenchymal stem cell therapy in cardiac ischemia treatment

    OpenAIRE

    Ceccaldi, Caroline; Bushkalova, Raya; Alfarano, Chiara; Lairez, Olivier; Calise, Denis; Bourin, Philippe; Frugier, Céline; Rouzaud-Laborde, Charlotte; Cussac, Daniel; Parini, Angelo; Sallerin, Brigitte; Girod Fullana, Sophie

    2014-01-01

    Three-dimensional (3D) scaffolds hold great potential for stem cell-based therapies. Indeed, recent results have shown that biomimetic scaffolds may enhance cell survival and promote an increase in the concentration of therapeutic cells at the injury site. The aim of this work was to engineer an original polymeric scaffold based on the respective beneficial effects of alginate and chitosan. Formulations were made from various alginate/chitosan ratios to form opposite-charge polyelectrolyte co...

  7. Three-dimensional biomedical imaging

    International Nuclear Information System (INIS)

    Robb, R.A.

    1985-01-01

    Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

  8. Influence of semisynthetic modification of the scaffold of a contact domain of HbS on polymerization: role of flexible surface topology in polymerization inhibition.

    Science.gov (United States)

    Sonati, Srinivasulu; Bhutoria, Savita; Prabhakaran, Muthuchidambaran; Acharya, Seetharama A

    2018-02-01

    A new variant of HbS, HbS-Einstein with a deletion of segment α 23-26 in the B-helix, has been assembled by semisynthetic approach. B-helix of the α chain of cis αβ-dimer of HbS plays dominant role in the quinary interactions of deoxy HbS dimer. This B-helix is the primary scaffold that provides the orientation for the side chains of contact residues of this intermolecular contact domain. The design of HbS-Einstein has been undertaken to map the influence of perturbation of molecular surface topology and the flexibility of surface residues in the polymerization. The internal deletion exerts a strong inhibitory influence on Val-6 (β)-dependent polymerization, comparable to single contact site mutations and not for complete neutralization of Val-6(β)-dependent polymerization. The scaffold modification in cis-dimer is inhibitory, and is without any effect when present on the trans dimer. The flexibility changes in the surface topology in the region of scaffold modification apparently counteracts the intrinsic polymerization potential of the molecule. The inhibition is close to that of Le Lamentin mutation [His-20 (α) → Gln] wherein a mutation engineered without much change in flexibility of the contact domain. Interestingly, the chimeric HbS with swine-human chimeric α chain with multiple non-conservative mutations completely inhibits the Val-6(β)-dependent polymerization. The deformabilities of surface topology of chimeric HbS are comparable to HbS in spite of the multiple contact site mutations in the α-chain. We conclude that the design of antisickling Hbs for gene therapy of sickle cell disease should involve multiple mutations of intermolecular contact sites.

  9. Fabrication of hydroxyapatite-baghdadite nanocomposite scaffolds coated by PCL/Bioglass with polyurethane polymeric sponge technique

    Directory of Open Access Journals (Sweden)

    Ebrahim Karamian

    2017-07-01

    Full Text Available Objecttive (s: Silicate bioceramics like Baghdadite with chemical formula Ca3ZrSi2O9, has attracted the attention of researchers in biomedical field due to its remarkable in-vitro and in-vivo bioactivity and mechanical properties.Materials and Methods: Therefore, in the current study the baghdadite powder with Sol-Gel method was synthesized. Then, hydroxyapatite/Baghdadite (HA/Bagh scaffolds were prepared by the replacing the polyurethane polymeric sponge technique. Afterwhile, the ceramic scaffolds were sintered at 1150ºC for 3 h. The prepared scaffold was then coated by polycaprolactone/bioglass (PCL/BG polymer nanocomposite. Results: Bioactivity and biomineralization in the simulated body fluid (SBF revealed that the nanocomposite scaffolds coate with PCL/BG had significant bioactivity properties. The morophology and microstructure investigation of soaked samples in SBF indicate that bone-like apatite formed on the surfaces. Also, ion release in SBF containing the scaffolds was measured by inductively coupled plasma (ICP analysis. The nucleation positions of apatite crystals were areas with high silicon containing, Si+4 ion positions.Conclusion: The study indicates that scaffold containing 30 wt. % baghdadite had proper bioactivity behaviordue to its ability to form bone-like apatite on the surface of specimens.

  10. In vitro degradation and mechanical properties of PLA-PCL copolymer unit cell scaffolds generated by two-photon polymerization

    International Nuclear Information System (INIS)

    Felfel, R M; Gimeno-Fabra, Miquel; Ahmed, Ifty; Scotchford, Colin; Grant, David M; Poocza, Leander; Milde, Tobias; Hildebrand, Gerhard; Liefeith, Klaus; Sottile, Virginie

    2016-01-01

    The manufacture of 3D scaffolds with specific controlled porous architecture, defined microstructure and an adjustable degradation profile was achieved using two-photon polymerization (TPP) with a size of 2  ×  4  ×  2 mm 3 . Scaffolds made from poly(D,L-lactide-co-ε-caprolactone) copolymer with varying lactic acid (LA) and ε -caprolactone (CL) ratios (LC16:4, 18:2 and 9:1) were generated via ring-opening-polymerization and photoactivation. The reactivity was quantified using photo-DSC, yielding a double bond conversion ranging from 70% to 90%. The pore sizes for all LC scaffolds were see 300 μm and throat sizes varied from 152 to 177 μm. In vitro degradation was conducted at different temperatures; 37, 50 and 65 °C. Change in compressive properties immersed at 37 °C over time was also measured. Variations in thermal, degradation and mechanical properties of the LC scaffolds were related to the LA/CL ratio. Scaffold LC16:4 showed significantly lower glass transition temperature (T g ) (4.8 °C) in comparison with the LC 18:2 and 9:1 (see 32 °C). Rates of mass loss for the LC16:4 scaffolds at all temperatures were significantly lower than that for LC18:2 and 9:1. The degradation activation energies for scaffold materials ranged from 82.7 to 94.9 kJ mol −1 . A prediction for degradation time was applied through a correlation between long-term degradation studies at 37 °C and short-term studies at elevated temperatures (50 and 65 °C) using the half-life of mass loss (Time (M 1/2 )) parameter. However, the initial compressive moduli for LC18:2 and 9:1 scaffolds were 7 to 14 times higher than LC16:4 (see 0.27) which was suggested to be due to its higher CL content (20%). All scaffolds showed a gradual loss in their compressive strength and modulus over time as a result of progressive mass loss over time. The manufacturing process utilized and the scaffolds produced have potential for use in tissue engineering and regenerative medicine

  11. (Weakly) three-dimensional caseology

    International Nuclear Information System (INIS)

    Pomraning, G.C.

    1996-01-01

    The singular eigenfunction technique of Case for solving one-dimensional planar symmetry linear transport problems is extended to a restricted class of three-dimensional problems. This class involves planar geometry, but with forcing terms (either boundary conditions or internal sources) which are weakly dependent upon the transverse spatial variables. Our analysis involves a singular perturbation about the classic planar analysis, and leads to the usual Case discrete and continuum modes, but modulated by weakly dependent three-dimensional spatial functions. These functions satisfy parabolic differential equations, with a different diffusion coefficient for each mode. Representative one-speed time-independent transport problems are solved in terms of these generalised Case eigenfunctions. Our treatment is very heuristic, but may provide an impetus for more rigorous analysis. (author)

  12. Equilibrium: three-dimensional configurations

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    This chapter considers toroidal MHD configurations that are inherently three-dimensional. The motivation for investigation such complicated equilibria is that they possess the potential for providing toroidal confinement without the need of a net toroidal current. This leads to a number of advantages with respect to fusion power generation. First, the attractive feature of steady-state operation becomes more feasible since such configurations no longer require a toroidal current transformer. Second, with zero net current, one potentially dangerous class of MHD instabilities, the current-driven kink modes, is eliminated. Finally, three-dimensional configurations possess nondegenerate flux surfaces even in the absence of plasma pressure and plasma current. Although there is an enormous range of possible three-dimensional equilibria, the configurations of interest are accurately described as axisymmetric tori with superimposed helical fields; furthermore, they possess no net toroidal current. Instead, two different and less obvious restoring forces are developed: the helical sideband force and the toroidal dipole current force. Each is discussed in detail in Chapter 7. A detailed discussion of the parallel current constraint, including its physical significance, is given in section 7.2. A general analysis of helical sideband equilibria, along with a detailed description of the Elmo bumpy torus, is presented in sections 7.3 and 7.4. A general description of toroidal dipole-current equilibria, including a detailed discussion of stellarators, heliotrons, and torsatrons, is given in sections 7.5 and 7.6

  13. Cell-matrix mechanical interaction in electrospun polymeric scaffolds for tissue engineering: Implications for scaffold design and performance.

    Science.gov (United States)

    Kennedy, Kelsey M; Bhaw-Luximon, Archana; Jhurry, Dhanjay

    2017-03-01

    Engineered scaffolds produced by electrospinning of biodegradable polymers offer a 3D, nanofibrous environment with controllable structural, chemical, and mechanical properties that mimic the extracellular matrix of native tissues and have shown promise for a number of tissue engineering applications. The microscale mechanical interactions between cells and electrospun matrices drive cell behaviors including migration and differentiation that are critical to promote tissue regeneration. Recent developments in understanding these mechanical interactions in electrospun environments are reviewed, with emphasis on how fiber geometry and polymer structure impact on the local mechanical properties of scaffolds, how altering the micromechanics cues cell behaviors, and how, in turn, cellular and extrinsic forces exerted on the matrix mechanically remodel an electrospun scaffold throughout tissue development. Techniques used to measure and visualize these mechanical interactions are described. We provide a critical outlook on technological gaps that must be overcome to advance the ability to design, assess, and manipulate the mechanical environment in electrospun scaffolds toward constructs that may be successfully applied in tissue engineering and regenerative medicine. Tissue engineering requires design of scaffolds that interact with cells to promote tissue development. Electrospinning is a promising technique for fabricating fibrous, biomimetic scaffolds. Effects of electrospun matrix microstructure and biochemical properties on cell behavior have been extensively reviewed previously; here, we consider cell-matrix interaction from a mechanical perspective. Micromechanical properties as a driver of cell behavior has been well established in planar substrates, but more recently, many studies have provided new insights into mechanical interaction in fibrillar, electrospun environments. This review provides readers with an overview of how electrospun scaffold mechanics and

  14. Tough and flexible CNT-polymeric hybrid scaffolds for engineering cardiac constructs.

    Science.gov (United States)

    Kharaziha, Mahshid; Shin, Su Ryon; Nikkhah, Mehdi; Topkaya, Seda Nur; Masoumi, Nafiseh; Annabi, Nasim; Dokmeci, Mehmet R; Khademhosseini, Ali

    2014-08-01

    In the past few years, a considerable amount of effort has been devoted toward the development of biomimetic scaffolds for cardiac tissue engineering. However, most of the previous scaffolds have been electrically insulating or lacked the structural and mechanical robustness to engineer cardiac tissue constructs with suitable electrophysiological functions. Here, we developed tough and flexible hybrid scaffolds with enhanced electrical properties composed of carbon nanotubes (CNTs) embedded aligned poly(glycerol sebacate):gelatin (PG) electrospun nanofibers. Incorporation of varying concentrations of CNTs from 0 to 1.5% within the PG nanofibrous scaffolds (CNT-PG scaffolds) notably enhanced fiber alignment and improved the electrical conductivity and toughness of the scaffolds while maintaining the viability, retention, alignment, and contractile activities of cardiomyocytes (CMs) seeded on the scaffolds. The resulting CNT-PG scaffolds resulted in stronger spontaneous and synchronous beating behavior (3.5-fold lower excitation threshold and 2.8-fold higher maximum capture rate) compared to those cultured on PG scaffold. Overall, our findings demonstrated that aligned CNT-PG scaffold exhibited superior mechanical properties with enhanced CM beating properties. It is envisioned that the proposed hybrid scaffolds can be useful for generating cardiac tissue constructs with improved organization and maturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Three-dimensional aromatic networks.

    Science.gov (United States)

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  16. New depowdering-friendly designs for three-dimensional printing of calcium phosphate bone substitutes

    NARCIS (Netherlands)

    Butscher, A.; Bohner, M.; Doebelin, N.; Hofmann, S.; Müller, R.

    2013-01-01

    Powder-based three-dimensional printing (3DP) is a versatile method that allows creating synthetic cal- cium phosphate (CaP) scaffolds of complex shapes and structures. However, one major drawback is the difficulty of removing all remnants of loose powder from the printed scaffolds, the so-called

  17. Three dimensional imaging of otoliths

    International Nuclear Information System (INIS)

    Barry, B.; Markwitz, A.; David, B.

    2008-01-01

    Otoliths are small structures in fish ears made of calcium carbonate which carry a record of the environment in which the fish live. Traditionally, in order to study their microchemistry by a scanning technique such as PIXE the otoliths have been either ground down by hand or thin sectioned to expose the otolith core. However this technique is subject to human error in judging the core position. In this study we have scanned successive layers of otoliths 50 and 100 μm apart by removing the otolith material in a lapping machine which can be set to a few μm precision. In one study by comparing data from otoliths from the two ears of a freshwater species we found that polishing by hand could miss the core and thus give misleading results as to the life cycle of the fish. In another example we showed detail in a marine species which could be used to build a three dimensional picture of the Sr distribution. (author)

  18. Three-Dimensional Rebar Graphene.

    Science.gov (United States)

    Sha, Junwei; Salvatierra, Rodrigo V; Dong, Pei; Li, Yilun; Lee, Seoung-Ki; Wang, Tuo; Zhang, Chenhao; Zhang, Jibo; Ji, Yongsung; Ajayan, Pulickel M; Lou, Jun; Zhao, Naiqin; Tour, James M

    2017-03-01

    Free-standing robust three-dimensional (3D) rebar graphene foams (GFs) were developed by a powder metallurgy template method with multiwalled carbon nanotubes (MWCNTs) as a reinforcing bar, sintered Ni skeletons as a template and catalyst, and sucrose as a solid carbon source. As a reinforcement and bridge between different graphene sheets and carbon shells, MWCNTs improved the thermostability, storage modulus (290.1 kPa) and conductivity (21.82 S cm -1 ) of 3D GF resulting in a high porosity and structurally stable 3D rebar GF. The 3D rebar GF can support >3150× the foam's weight with no irreversible height change, and shows only a ∼25% irreversible height change after loading >8500× the foam's weight. The 3D rebar GF also shows stable performance as a highly porous electrode in lithium ion capacitors (LICs) with an energy density of 32 Wh kg -1 . After 500 cycles of testing at a high current density of 6.50 mA cm -2 , the LIC shows 78% energy density retention. These properties indicate promising applications with 3D rebar GFs in devices requiring stable mechanical and electrochemical properties.

  19. Physicochemical properties and enhanced cellullar responses of biocompatible polymeric scaffolds treated with atmospheric pressure plasma using O{sub 2} gas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun-Uk; Park, So-Young; Kang, Yoon-Hee [Department of Nano Fusion Technology, Pusan National University, Busan 609735 (Korea, Republic of); Jeong, Se-Young [Division of Cogni-mechatronics Engineering, Pusan National University, Miryang 627706 (Korea, Republic of); Choi, Sae-Hae; Jahng, Yoon-Young; Chung, Gook-Hyun [Division of Biological Sciences, Chonbuk National University, Jeonju 561756 (Korea, Republic of); Kim, Moon-Bum [Department of Dermatology, School of Medicine, Pusan National University, Busan (Korea, Republic of); Cho, Chae-Ryong, E-mail: crcho@pusan.ac.kr [Department of Nano Fusion Technology, Pusan National University, Busan 609735 (Korea, Republic of)

    2011-04-08

    Biocompatible polymeric scaffolds were fabricated by mixing 5 wt.% poly({epsilon}-caprolactone) (P) with 4 wt.% gelatin (G) and 1.6 wt.% Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (D). These PGD scaffolds were also treated with atmospheric pressure (AP) plasma using O{sub 2} reactive gas (to create O-PGD scaffolds). The physicochemical and mechanical properties of the PGD scaffolds were characterized by in vitro biodegradability tests, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, and tensile strength measurements. The wettability and hydrophilic properties of the scaffold surface were improved remarkably by adding G and D to P, and by subsequent oxygen-assisted AP plasma treatment. An MTT assay, a cell attachment efficiency assay, scanning electron microscopy, and confocal microscopy revealed that Chinese Hamster Ovary (CHO)-K1 cells exhibited higher cell attachment and viability on the PGD and O-PGD scaffolds than on the P and PG scaffolds. Furthermore, the long-term viability of the CHO cells on the PGD and O-PGD scaffolds without exchanging the cell culture media was significantly improved compared to their viability on the P and PG scaffolds. Overall, the PGD and O-PGD scaffolds are expected to be useful as cell growth supporting biomaterials in tissue engineering.

  20. Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound.

    Science.gov (United States)

    Mercado, Karla P; Helguera, María; Hocking, Denise C; Dalecki, Diane

    2015-07-01

    Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13-47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices.

  1. Retention of insulin-like growth factor I bioactivity during the fabrication of sintered polymeric scaffolds

    International Nuclear Information System (INIS)

    Clark, Amanda; Puleo, David A; Milbrandt, Todd A; Hilt, J Zach

    2014-01-01

    The use of growth factors in tissue engineering offers an added benefit to cartilage regeneration. Growth factors, such as insulin-like growth factor I (IGF-I), increase cell proliferation and can therefore decrease the time it takes for cartilage tissue to regrow. In this study, IGF-I was released from poly(lactic-co-glycolic acid) (PLGA) scaffolds that were designed to have a decreased burst release often associated with tissue engineering scaffolds. The scaffolds were fabricated from IGF-I-loaded PLGA microspheres prepared by a double emulsion (W 1 /O/W 2 ) technique. The microspheres were then compressed, sintered at 49 °C and salt leached. The bioactivity of soluble IGF-I was verified after being heat treated at 37, 43, 45, 49 and 60 °C. Additionally, the bioactivity of IGF-I was confirmed after being released from the sintered scaffolds. The triphasic release lasted 120 days resulting in 20%, 55% and 25% of the IGF-I being released during days 1–3, 4–58 and 59–120, respectively. Seeding bone marrow cells directly onto the IGF-I-loaded scaffolds showed an increase in cell proliferation, based on DNA content, leading to increased glycosaminoglycan production. The present results demonstrated that IGF-I remains active after being incorporated into heat-treated scaffolds, further enhancing tissue regeneration possibilities. (paper)

  2. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds.

    Science.gov (United States)

    Flaibani, Marina; Elvassore, Nicola

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (~70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Three-dimensional strutted graphene grown by substrate-free sugar blowing for high-power-density supercapacitors

    Science.gov (United States)

    Wang, Xuebin; Zhang, Yuanjian; Zhi, Chunyi; Wang, Xi; Tang, Daiming; Xu, Yibin; Weng, Qunhong; Jiang, Xiangfen; Mitome, Masanori; Golberg, Dmitri; Bando, Yoshio

    2013-12-01

    Three-dimensional graphene architectures in the macroworld can in principle maintain all the extraordinary nanoscale properties of individual graphene flakes. However, current 3D graphene products suffer from poor electrical conductivity, low surface area and insufficient mechanical strength/elasticity; the interconnected self-supported reproducible 3D graphenes remain unavailable. Here we report a sugar-blowing approach based on a polymeric predecessor to synthesize a 3D graphene bubble network. The bubble network consists of mono- or few-layered graphitic membranes that are tightly glued, rigidly fixed and spatially scaffolded by micrometre-scale graphitic struts. Such a topological configuration provides intimate structural interconnectivities, freeway for electron/phonon transports, huge accessible surface area, as well as robust mechanical properties. The graphene network thus overcomes the drawbacks of presently available 3D graphene products and opens up a wide horizon for diverse practical usages, for example, high-power high-energy electrochemical capacitors, as highlighted in this work.

  4. Protein-releasing polymeric scaffolds induce fibrochondrocytic differentiation of endogenous cells for knee meniscus regeneration in sheep

    Science.gov (United States)

    Lee, Chang H.; Rodeo, Scott A.; Fortier, Lisa Ann; Lu, Chuanyong; Erisken, Cevat

    2015-01-01

    Regeneration of complex tissues, such as kidney, liver, and cartilage, continues to be a scientific and translational challenge. Survival of ex vivo cultured, transplanted cells in tissue grafts is among one of the key barriers. Meniscus is a complex tissue consisting of collagen fibers and proteoglycans with gradient phenotypes of fibrocartilage and functions to provide congruence of the knee joint, without which the patient is likely to develop arthritis. Endogenous stem/progenitor cells regenerated the knee meniscus upon spatially released human connective tissue growth factor (CTGF) and transforming growth factor–β3 (TGFβ3) from a three-dimensional (3D)–printed biomaterial, enabling functional knee recovery. Sequentially applied CTGF and TGFβ3 were necessary and sufficient to propel mesenchymal stem/progenitor cells, as a heterogeneous population or as single-cell progenies, into fibrochondrocytes that concurrently synthesized procollagens I and IIα. When released from microchannels of 3D–printed, human meniscus scaffolds, CTGF and TGFβ3 induced endogenous stem/progenitor cells to differentiate and synthesize zone-specific type I and II collagens. We then replaced sheep meniscus with anatomically correct, 3D–printed scaffolds that incorporated spatially delivered CTGF and TGFβ3. Endogenous cells regenerated the meniscus with zone-specific matrix phenotypes: primarily type I collagen in the outer zone, and type II collagen in the inner zone, reminiscent of the native meniscus. Spatiotemporally delivered CTGF and TGFβ3 also restored inhomogeneous mechanical properties in the regenerated sheep meniscus. Survival and directed differentiation of endogenous cells in a tissue defect may have implications in the regeneration of complex (heterogeneous) tissues and organs. PMID:25504882

  5. Elastocapillary fabrication of three-dimensional microstructures

    NARCIS (Netherlands)

    van Honschoten, J.W.; Berenschot, Johan W.; Ondarcuhu, T.; Sanders, Remco G.P.; Sundaram, J.; Elwenspoek, Michael Curt; Tas, Niels Roelof

    2010-01-01

    We describe the fabrication of three-dimensional microstructures by means of capillary forces. Using an origami-like technique, planar silicon nitride structures of various geometries are folded to produce three-dimensional objects of 50–100 m. Capillarity is a particularly effective mechanism since

  6. A Review of Three-Dimensional Printing in Tissue Engineering.

    Science.gov (United States)

    Sears, Nick A; Seshadri, Dhruv R; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth

    2016-08-01

    Recent advances in three-dimensional (3D) printing technologies have led to a rapid expansion of applications from the creation of anatomical training models for complex surgical procedures to the printing of tissue engineering constructs. In addition to achieving the macroscale geometry of organs and tissues, a print layer thickness as small as 20 μm allows for reproduction of the microarchitectures of bone and other tissues. Techniques with even higher precision are currently being investigated to enable reproduction of smaller tissue features such as hepatic lobules. Current research in tissue engineering focuses on the development of compatible methods (printers) and materials (bioinks) that are capable of producing biomimetic scaffolds. In this review, an overview of current 3D printing techniques used in tissue engineering is provided with an emphasis on the printing mechanism and the resultant scaffold characteristics. Current practical challenges and technical limitations are emphasized and future trends of bioprinting are discussed.

  7. Impregnation of β-​tricalcium phosphate robocast scaffolds by in situ polymerization

    NARCIS (Netherlands)

    Martinez-Vazquez, F.J.; Perera, F.H.; Meulen, van der I.; Heise, A.; Pajares, A.; Miranda, P.

    2013-01-01

    Ring-¿opening polymn. of e-¿caprolactone (e-¿CL) and L-¿lactide (LLA) was performed to impregnate ß-¿tricalcium phosphate (ß-¿TCP) scaffolds fabricated by robocasting. Concd. colloidal inks prepd. from ß-¿TCP com. powders were used to fabricate porous structures consisting of a 3D mesh of

  8. Evaluation of cellular adhesion and organization in different microporous polymeric scaffolds.

    Science.gov (United States)

    Asthana, Amish; White, Charles McRae; Douglass, Megan; Kisaalita, William S

    2018-03-01

    The lack of prediction accuracy during drug development and screening risks complications during human trials, such as drug-induced liver injury (DILI), and has led to a demand for robust, human cell-based, in vitro assays for drug discovery. Microporous polymer-based scaffolds offer an alternative to the gold standard flat tissue culture plastic (2D TCPS) and other 3D cell culture platforms as the porous material entraps cells, making it advantageous for automated liquid handlers and high-throughput screening (HTS). In this study, we optimized the surface treatment, pore size, and choice of scaffold material with respect to cellular adhesion, tissue organization, and expression of complex physiologically relevant (CPR) outcomes such as the presence of bile canaliculi-like structures. Poly-l-lysine and fibronectin (FN) coatings have been shown to encourage cell attachment to the underlying substrate. Treatment of the scaffold surface with NaOH followed with a coating of FN improved cell attachment and penetration into pores. Of the two pore sizes we investigated (A: 104 ± 4 μm; B: 175 ± 6 μm), the larger pore size better promoted cell penetration while limiting tissue growth from reaching the hypoxia threshold. Finally, polystyrene (PS) proved to be conducive to cell growth, penetration into the scaffold, and yielded CPR outcomes while being a cost-effective choice for HTS applications. These observations provide a foundation for optimizing microporous polymer-based scaffolds suitable for drug discovery. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:505-514, 2018. © 2018 American Institute of Chemical Engineers.

  9. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Flaibani, Marina; Elvassore, Nicola, E-mail: nicola.elvassore@unipd.it

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity ({approx} 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: Black-Right-Pointing-Pointer Gas anti-solvent precipitation and salt leaching for scaffold fabrication. Black-Right-Pointing-Pointer Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. Black-Right-Pointing-Pointer Gas anti-solvent precipitation

  10. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    International Nuclear Information System (INIS)

    Flaibani, Marina; Elvassore, Nicola

    2012-01-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10–15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177–0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (∼ 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: ► Gas anti-solvent precipitation and salt leaching for scaffold fabrication. ► Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. ► Gas anti-solvent precipitation induces nano-porous structures. ► Scaffolds are biocompatible and

  11. Electrospun three dimensional scaffolds for bone tissue regeneration

    OpenAIRE

    Paşcu, Elena Irina

    2013-01-01

    Bone is a complex and highly specialized form of connective tissue which acts as the main supporting organ of the body. It is hard and dynamic by its nature, with a unique combination of organic and inorganic elements embedded in a fibrous extracellular matrix (ECM), onto which cells attach, proliferate and differentiate. When bone repair mechanisms fail, due to infection or defect magnitude, bone formation can be stimulated with the use of autologous bone grafts or donor allografts. However,...

  12. 3D scaffolds from vertically aligned carbon nanotubes/poly(methyl methacrylate) composites via atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Tebikachew, Behabtu; Magina, Sandra [CICECO, Department of Chemistry, University of Aveiro (Portugal); Mata, Diogo; Oliveira, Filipe J.; Silva, Rui F. [CICECO, Department of Materials and Ceramic Engineering, University of Aveiro (Portugal); Barros-Timmons, Ana, E-mail: anabarros@ua.pt [CICECO, Department of Chemistry, University of Aveiro (Portugal)

    2015-01-15

    Vertically aligned carbon nanotubes (VACNTs) synthesized by Thermal Chemical Vapour Deposition (TCVD) were modified using an Ar:O{sub 2} (97:3) plasma to generate oxygen-containing functional groups on the surface for subsequent modification. X-ray photo-emission spectroscopy (XPS) and micro-Raman analyses confirmed the grafting of those functional groups onto the surface of the nanotubes as well as the removal of amorphous carbon produced and deposited on the VACNT forests during the CVD process. The plasma treated VACNT forests were further modified with 2-bromo-2-methylpropionyl bromide, an atom transfer radical polymerization (ATRP) initiator, to grow poly(methyl methacrylate) (PMMA) chains from the forests via ATRP. Scanning transmission electron microscopy (STEM) of the ensuing VACNT/PMMA composites confirmed the coating of the nanotube forests with the PMMA polymer. 3D scaffolds of polymeric composites with honeycomb like structure were then obtained. Compressive tests have shown that the VACNT/PMMA composite has higher compressive strength than the pristine forest. - Highlights: • Vertically aligned carbon nanotubes (VACNTs) were synthesized and plasma modified. • X-ray photo-emission and Raman spectroscopies confirmed the VACNTs modification. • Poly(methyl methacrylate) chains were grown via ATRP from the VACNTs. • STEM of the VACNT/PMMA composites confirmed that PMMA surrounds the nanotubes. • VACNT/PMMA composite has higher compressive strength compared to the pristine forest.

  13. 3D scaffolds from vertically aligned carbon nanotubes/poly(methyl methacrylate) composites via atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Tebikachew, Behabtu; Magina, Sandra; Mata, Diogo; Oliveira, Filipe J.; Silva, Rui F.; Barros-Timmons, Ana

    2015-01-01

    Vertically aligned carbon nanotubes (VACNTs) synthesized by Thermal Chemical Vapour Deposition (TCVD) were modified using an Ar:O 2 (97:3) plasma to generate oxygen-containing functional groups on the surface for subsequent modification. X-ray photo-emission spectroscopy (XPS) and micro-Raman analyses confirmed the grafting of those functional groups onto the surface of the nanotubes as well as the removal of amorphous carbon produced and deposited on the VACNT forests during the CVD process. The plasma treated VACNT forests were further modified with 2-bromo-2-methylpropionyl bromide, an atom transfer radical polymerization (ATRP) initiator, to grow poly(methyl methacrylate) (PMMA) chains from the forests via ATRP. Scanning transmission electron microscopy (STEM) of the ensuing VACNT/PMMA composites confirmed the coating of the nanotube forests with the PMMA polymer. 3D scaffolds of polymeric composites with honeycomb like structure were then obtained. Compressive tests have shown that the VACNT/PMMA composite has higher compressive strength than the pristine forest. - Highlights: • Vertically aligned carbon nanotubes (VACNTs) were synthesized and plasma modified. • X-ray photo-emission and Raman spectroscopies confirmed the VACNTs modification. • Poly(methyl methacrylate) chains were grown via ATRP from the VACNTs. • STEM of the VACNT/PMMA composites confirmed that PMMA surrounds the nanotubes. • VACNT/PMMA composite has higher compressive strength compared to the pristine forest

  14. Three dimensional visualization of medical images

    International Nuclear Information System (INIS)

    Suto, Yasuzo

    1992-01-01

    Three dimensional visualization is a stereoscopic technique that allows the diagnosis and treatment of complicated anatomy site of the bone and organ. In this article, the current status and technical application of three dimensional visualization are introduced with special reference to X-ray CT and MRI. The surface display technique is the most common for three dimensional visualization, consisting of geometric model, voxel element, and stereographic composition techniques. Recent attention has been paid to display method of the content of the subject called as volume rendering, whereby information on the living body is provided accurately. The application of three dimensional visualization is described in terms of diagnostic imaging and surgical simulation. (N.K.)

  15. three dimensional photoelastic investigations on thick rectangular

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... Thick rectangular plates are investigated by means of three-dimensional photoelasticity ... a thin plate theory and a higher order thick plate theory. 1. ..... number of fringes lest the accuracy of the results will be considerably.

  16. Three dimensional diffusion calculations of nuclear reactors

    International Nuclear Information System (INIS)

    Caspo, N.

    1981-07-01

    This work deals with the three dimensional calculation of nuclear reactors using the code TRITON. The purposes of the work were to perform three-dimensional computations of the core of the Soreq nuclear reactor and of the power reactor ZION and to validate the TRITON code. Possible applications of the TRITON code in Soreq reactor calculations and in power reactor research are suggested. (H.K.)

  17. Three-dimensional effects in fracture mechanics

    International Nuclear Information System (INIS)

    Benitez, F.G.

    1991-01-01

    An overall view of the pioneering theories and works, which enlighten the three-dimensional nature of fracture mechanics during the last years is given. the main aim is not an exhaustive reviewing but the displaying of the last developments on this scientific field in a natural way. This work attempts to envisage the limits of disregarding the three-dimensional behaviour in theories, analyses and experiments. Moreover, it tries to draw attention on the scant fervour, although increasing, this three-dimensional nature of fracture has among the scientific community. Finally, a constructive discussion is presented on the use of two-dimensional solutions in the analysis of geometries which bear a three-dimensional configuration. the static two-dimensional solutions and its applications fields are reviewed. also, the static three-dimensional solutions, wherein a comparative analysis with elastoplastic and elastostatic solutions are presented. to end up, the dynamic three-dimensional solutions are compared to the asymptotic two-dimensional ones under the practical applications point of view. (author)

  18. Density gradient multilayered polymerization (DGMP): a novel technique for creating multi-compartment, customizable scaffolds for tissue engineering.

    Science.gov (United States)

    Joshi-Barr, Shivanjali; Karpiak, Jerome V; Ner, Yogesh; Wen, Jessica H; Engler, Adam J; Almutairi, Adah

    2013-02-12

    Complex tissue culture matrices, in which types and concentrations of biological stimuli (e.g. growth factors, inhibitors, or small molecules) or matrix structure (e.g. composition, concentration, or stiffness of the matrix) vary over space, would enable a wide range of investigations concerning how these variables affect cell differentiation, migration, and other phenomena. The major challenge in creating layered matrices is maintaining the structural integrity of layer interfaces without diffusion of individual components from each layer. Current methodologies to achieve this include photopatterning, lithography, sequential functionalization5, freeze drying, microfluidics, or centrifugation, many of which require sophisticated instrumentation and technical skills. Others rely on sequential attachment of individual layers, which may lead to delamination of layers. DGMP overcomes these issues by using an inert density modifier such as iodixanol to create layers of varying densities. Since the density modifier can be mixed with any prepolymer or bioactive molecule, DGMP allows each scaffold layer to be customized. Simply varying the concentration of the density modifier prevents mixing of adjacent layers while they remain aqueous. Subsequent single step polymerization gives rise to a structurally continuous multilayered scaffold, in which each layer has distinct chemical and mechanical properties. The density modifier can be easily removed with sufficient rinsing without perturbation of the individual layers or their components. This technique is therefore well suited for creating hydrogels of various sizes, shapes, and materials. A protocol for fabricating a 2D-polyethylene glycol (PEG) gel, in which alternating layers incorporate RGDS-350, is outlined below. We use PEG because it is biocompatible and inert. RGDS, a cell adhesion peptide, is used to demonstrate spatial restriction of a biological cue, and the conjugation of a fluorophore (Alexa Fluor 350) enables

  19. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    Science.gov (United States)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  20. Three-dimensional microbubble streaming flows

    Science.gov (United States)

    Rallabandi, Bhargav; Marin, Alvaro; Rossi, Massimiliano; Kaehler, Christian; Hilgenfeldt, Sascha

    2014-11-01

    Streaming due to acoustically excited bubbles has been used successfully for applications such as size-sorting, trapping and focusing of particles, as well as fluid mixing. Many of these applications involve the precise control of particle trajectories, typically achieved using cylindrical bubbles, which establish planar flows. Using astigmatic particle tracking velocimetry (APTV), we show that, while this two-dimensional picture is a useful description of the flow over short times, a systematic three-dimensional flow structure is evident over long time scales. We demonstrate that this long-time three-dimensional fluid motion can be understood through asymptotic theory, superimposing secondary axial flows (induced by boundary conditions at the device walls) onto the two-dimensional description. This leads to a general framework that describes three-dimensional flows in confined microstreaming systems, guiding the design of applications that profit from minimizing or maximizing these effects.

  1. Laboratory injection molder for the fabrication of polymeric porous poly-epsilon-caprolactone scaffolds for preliminary mesenchymal stem cells tissue engineering applications

    KAUST Repository

    Limongi, Tania

    2016-12-16

    This study presents a simple and rapid fabrication technique involving injection molding and particle leaching (IM/PL) to fabricate the porous scaffold for tissue engineering applications. Sodium chloride (NaCl) and Sucrose are separately mixed with the poly-epsilon-caprolactone (PCL) granules using a screwed thermo regulated extruder, than the biocompatible scaffolds are fabricated through injection molding. The micro/nano structure of the samples and their different grade of porosity were characterized by scanning electron microscopy and mercury intrusion porosimetry. Bone marrow-derived mesenchymal stem cells are chose to cell culture and Hoechst 33342 staining was used to verify the biocompatibility of the polymeric porous surfaces. We concluded that, by using the same fast solvent free injection/leaching process, the use of Sucrose as porogen, instead of NaCl, allowed the obtainment of biocompatible scaffolds with a higher grade of porosity with suitable cell adhesion capacity for tissue engineering purpose.

  2. Towards three-dimensional optical metamaterials

    Science.gov (United States)

    Tanaka, Takuo; Ishikawa, Atsushi

    2017-12-01

    Metamaterials have opened up the possibility of unprecedented and fascinating concepts and applications in optics and photonics. Examples include negative refraction, perfect lenses, cloaking, perfect absorbers, and so on. Since these metamaterials are man-made materials composed of sub-wavelength structures, their development strongly depends on the advancement of micro- and nano-fabrication technologies. In particular, the realization of three-dimensional metamaterials is one of the big challenges in this research field. In this review, we describe recent progress in the fabrication technologies for three-dimensional metamaterials, as well as proposed applications.

  3. Development of three dimensional solid modeler

    International Nuclear Information System (INIS)

    Zahoor, R.M.A.

    1999-01-01

    The work presented in this thesis is aimed at developing a three dimensional solid modeler employing computer graphics techniques using C-Language. Primitives have been generated, by combination of plane surfaces, for various basic geometrical shapes including cylinder, cube and cone. Back face removal technique for hidden surface removal has also been incorporated. Various transformation techniques such as scaling, translation, and rotation have been included for the object animation. Three dimensional solid modeler has been created by the union of two primitives to demonstrate the capabilities of the developed program. (author)

  4. Three-dimensional topological insulators and bosonization

    Energy Technology Data Exchange (ETDEWEB)

    Cappelli, Andrea [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Randellini, Enrico [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Sisti, Jacopo [Scuola Internazionale Superiore di Studi Avanzati (SISSA),Via Bonomea 265, 34136 Trieste (Italy)

    2017-05-25

    Massless excitations at the surface of three-dimensional time-reversal invariant topological insulators possess both fermionic and bosonic descriptions, originating from band theory and hydrodynamic BF theory, respectively. We analyze the corresponding field theories of the Dirac fermion and compactified boson and compute their partition functions on the three-dimensional torus geometry. We then find some non-dynamic exact properties of bosonization in (2+1) dimensions, regarding fermion parity and spin sectors. Using these results, we extend the Fu-Kane-Mele stability argument to fractional topological insulators in three dimensions.

  5. Three-dimensional imaging utilizing energy discrimination

    International Nuclear Information System (INIS)

    Gunter, D.L.; Hoffman, K.R.; Beck, R.N.

    1990-01-01

    An algorithm is proposed for three-dimensional image reconstruction in nuclear medicine which uses scattered radiation rather than multiple projected images to determine the source depth within the body. Images taken from numerous energy windows are combined to construct the source distribution in the body. The gamma-ray camera is not moved during the imaging process. Experiments with both Tc-99m and Ga-67 demonstrate that two channels of depth information can be extracted from the low energy images produced by scattered radiation. By combining this technique with standard SPECT reconstruction using multiple projections the authors anticipate much improved spatial resolution in the overall three-dimensional reconstruction

  6. Three-Dimensional Messages for Interstellar Communication

    Science.gov (United States)

    Vakoch, Douglas A.

    One of the challenges facing independently evolved civilizations separated by interstellar distances is to communicate information unique to one civilization. One commonly proposed solution is to begin with two-dimensional pictorial representations of mathematical concepts and physical objects, in the hope that this will provide a foundation for overcoming linguistic barriers. However, significant aspects of such representations are highly conventional, and may not be readily intelligible to a civilization with different conventions. The process of teaching conventions of representation may be facilitated by the use of three-dimensional representations redundantly encoded in multiple formats (e.g., as both vectors and as rasters). After having illustrated specific conventions for representing mathematical objects in a three-dimensional space, this method can be used to describe a physical environment shared by transmitter and receiver: a three-dimensional space defined by the transmitter--receiver axis, and containing stars within that space. This method can be extended to show three-dimensional representations varying over time. Having clarified conventions for representing objects potentially familiar to both sender and receiver, novel objects can subsequently be depicted. This is illustrated through sequences showing interactions between human beings, which provide information about human behavior and personality. Extensions of this method may allow the communication of such culture-specific features as aesthetic judgments and religious beliefs. Limitations of this approach will be noted, with specific reference to ETI who are not primarily visual.

  7. Three-Dimensional Printing Surgical Applications.

    Science.gov (United States)

    AlAli, Ahmad B; Griffin, Michelle F; Butler, Peter E

    2015-01-01

    Three-dimensional printing, a technology used for decades in the industrial field, gains a lot of attention in the medical field for its potential benefits. With advancement of desktop printers, this technology is accessible and a lot of research is going on in the medical field. To evaluate its application in surgical field, which may include but not limited to surgical planning, surgical education, implants, and prosthesis, which are the focus of this review. Research was conducted by searching PubMed, Web of science, and other reliable sources. We included original articles and excluded articles based on animals, those more than 10 years old, and those not in English. These articles were evaluated, and relevant studies were included in this review. Three-dimensional printing shows a potential benefit in surgical application. Printed implants were used in patient in a few cases and show successful results; however, longer follow-up and more trials are needed. Surgical and medical education is believed to be more efficient with this technology than the current practice. Printed surgical instrument and surgical planning are also believed to improve with three-dimensional printing. Three-dimensional printing can be a very powerful tool in the near future, which can aid the medical field that is facing a lot of challenges and obstacles. However, despite the reported results, further research on larger samples and analytical measurements should be conducted to ensure this technology's impact on the practice.

  8. Electron crystallography of three dimensional protein crystals

    NARCIS (Netherlands)

    Georgieva, Dilyana

    2008-01-01

    This thesis describes an investigation of the potential of electron diffraction for studying three dimensional sub-micro-crystals of proteins and pharmaceuticals. A prerequisite for using electron diffraction for structural studies is the predictable availability of tiny crystals. A method for

  9. Three dimensional electrochemical system for neurobiological studies

    DEFF Research Database (Denmark)

    Vazquez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2009-01-01

    In this work we report a novel three dimensional electrode array for electrochemical measurements in neuronal studies. The main advantage of working with these out-of-plane structures is the enhanced sensitivity of the system in terms of measuring electrochemical changes in the environment...

  10. Imaging unsteady three-dimensional transport phenomena

    Indian Academy of Sciences (India)

    2014-01-05

    Jan 5, 2014 ... The image data can be jointly analysed with the physical laws governing transport and principles of image formation. Hence, with the experiment suitably carried out, three-dimensional physical domains with unsteady processes can be accommodated. Optical methods promise to breach the holy grail of ...

  11. Computerized three-dimensional normal atlas

    International Nuclear Information System (INIS)

    Mano, Isamu; Suto, Yasuzo; Suzuki, Masataka; Iio, Masahiro.

    1990-01-01

    This paper presents our ongoing project in which normal human anatomy and its quantitative data are systematically arranged in a computer. The final product, the Computerized Three-Dimensional Normal Atlas, will be able to supply tomographic images in any direction, 3-D images, and coded information on organs, e.g., anatomical names, CT numbers, and T 1 and T 2 values. (author)

  12. Three-Dimensional Shallow Water Acoustics

    Science.gov (United States)

    2016-03-30

    medium properties, so horizontal refraction and reflection of sound can occur and produce significant three-dimensional (3-D) sound propagation ...by the environmental factors existing commonly in the continental shelf and shelfbreak areas, such as slopes, submarine canyons, sub-bottom layers ...surface waves, internal waves and shelfbreak fronts. 15. SUBJECT TERMS Continental Shelf; 3-D Acoustics , Surface Waves, Sound Propagation 16

  13. Spiral-structured, nanofibrous, 3D scaffolds for bone tissue engineering.

    Science.gov (United States)

    Wang, Junping; Valmikinathan, Chandra M; Liu, Wei; Laurencin, Cato T; Yu, Xiaojun

    2010-05-01

    Polymeric nanofiber matrices have already been widely used in tissue engineering. However, the fabrication of nanofibers into complex three-dimensional (3D) structures is restricted due to current manufacturing techniques. To overcome this limitation, we have incorporated nanofibers onto spiral-structured 3D scaffolds made of poly (epsilon-caprolactone) (PCL). The spiral structure with open geometries, large surface areas, and porosity will be helpful for improving nutrient transport and cell penetration into the scaffolds, which are otherwise limited in conventional tissue-engineered scaffolds for large bone defects repair. To investigate the effect of structure and fiber coating on the performance of the scaffolds, three groups of scaffolds including cylindrical PCL scaffolds, spiral PCL scaffolds (without fiber coating), and spiral-structured fibrous PCL scaffolds (with fiber coating) have been prepared. The morphology, porosity, and mechanical properties of the scaffolds have been characterized. Furthermore, human osteoblast cells are seeded on these scaffolds, and the cell attachment, proliferation, differentiation, and mineralized matrix deposition on the scaffolds are evaluated. The results indicated that the spiral scaffolds possess porosities within the range of human trabecular bone and an appropriate pore structure for cell growth, and significantly lower compressive modulus and strength than cylindrical scaffolds. When compared with the cylindrical scaffolds, the spiral-structured scaffolds demonstrated enhanced cell proliferation, differentiation, and mineralization and allowed better cellular growth and penetration. The incorporation of nanofibers onto spiral scaffolds further enhanced cell attachment, proliferation, and differentiation. These studies suggest that spiral-structured nanofibrous scaffolds may serve as promising alternatives for bone tissue engineering applications. Copyright 2009 Wiley Periodicals, Inc.

  14. Distribution and viability of fetal and adult human bone marrow stromal cells in a biaxial rotating vessel bioreactor after seeding on polymeric 3D additive manufactured scaffolds

    Directory of Open Access Journals (Sweden)

    Anne eLeferink

    2015-10-01

    Full Text Available One of the conventional approaches in tissue engineering is the use of scaffolds in combination with cells to obtain mechanically stable tissue constructs in vitro prior to implantation. Additive manufacturing by fused deposition modeling is a widely used technique to produce porous scaffolds with defined pore network, geometry, and therewith defined mechanical properties. Bone marrow derived mesenchymal stromal cells (MSCs are promising candidates for tissue engineering based cell therapies due to their multipotent character. One of the hurdles to overcome when combining additive manufactured scaffolds with MSCs is the resulting heterogeneous cell distribution and limited cell proliferation capacity. In this study, we show that the use of a biaxial rotating bioreactor, after static culture of human fetal MSCs (hfMSCs seeded on synthetic polymeric scaffolds, improved the homogeneity of cell and extracellular matrix (ECM distribution and increased the total cell number. Furthermore, we show that the relative mRNA expression levels of indicators for stemness and differentiation are not significantly changed upon this bioreactor culture, whereas static culture shows variations of several indicators for stemness and differentiation. The biaxial rotating bioreactor presented here offers a homogeneous distribution of hfMSCs, enabling studies on MSCs fate in additive manufactured scaffolds without inducing undesired differentiation.

  15. Three-dimensional bioprinting in tissue engineering and regenerative medicine.

    Science.gov (United States)

    Gao, Guifang; Cui, Xiaofeng

    2016-02-01

    With the advances of stem cell research, development of intelligent biomaterials and three-dimensional biofabrication strategies, highly mimicked tissue or organs can be engineered. Among all the biofabrication approaches, bioprinting based on inkjet printing technology has the promises to deliver and create biomimicked tissue with high throughput, digital control, and the capacity of single cell manipulation. Therefore, this enabling technology has great potential in regenerative medicine and translational applications. The most current advances in organ and tissue bioprinting based on the thermal inkjet printing technology are described in this review, including vasculature, muscle, cartilage, and bone. In addition, the benign side effect of bioprinting to the printed mammalian cells can be utilized for gene or drug delivery, which can be achieved conveniently during precise cell placement for tissue construction. With layer-by-layer assembly, three-dimensional tissues with complex structures can be printed using converted medical images. Therefore, bioprinting based on thermal inkjet is so far the most optimal solution to engineer vascular system to the thick and complex tissues. Collectively, bioprinting has great potential and broad applications in tissue engineering and regenerative medicine. The future advances of bioprinting include the integration of different printing mechanisms to engineer biphasic or triphasic tissues with optimized scaffolds and further understanding of stem cell biology.

  16. Study of biocompatible properties of polymeric scaffolds derived from vegetable oils for application in tissue engineering

    International Nuclear Information System (INIS)

    Baratela, Fernando Jose Costa

    2015-01-01

    Tissue engineering and regenerative medicine have as main objective the morphologic/functional reestablishment of injured tissues and organs using cells, scaffolds, stem cells and control of immunological/biochemical responses promoted by the body. In addition, materials science seeks to develop biocompatible biomaterials that do not promote unwanted immune responses and provide the re-establishment of the functions of the tissue/organ. Polymers of natural origin stand out as biomaterials to resemble biological macromolecules, similarity to the extracellular matrix, reduced chance of inflammation and chronic pacing low or no toxicity. This study aimed the development of macromolecular arrays originated from epoxidized soybean oil (OSE), analyzing the relationship between the chemical structure/biological activity of the macromolecular arrays for use as biomaterials in tissue engineering. The synthesis of OSE was performed through the oil chemical route, whose efficiency was determined by infrared spectroscopy and the reaction yield of 85%, determined by nuclear magnetic resonance spectroscopy. From the analysis by differential scanning calorimetry, it was detected a decrease of the glass transition temperature of the epoxidized soybean oil polymer (POSE) compared with OSE, suggesting an increase of the growth of polymer chains of POSE. Thermogravimetric analysis was performed to define the OSE degradation profile, which degrades in two steps. The POSE degrades in just one step and shows higher thermal stability by the increased molecular interactions. The hydrophilicity and crosslinking of POSE was promoted by the addition of 2-hydroxyethyl methacrylate (HEMA) with the monomer grafting by gamma irradiation. The results showed an increased mechanical stability, gelation and water absorption with the HEMA content increasing. Finally, the degree of crystallinity for such polymers grafted with HEMA was 27.5%, estimated by X-ray diffractometry. The second stage was

  17. 3D printing biodegradable scaffolds with chitosan materials for tissue engineering

    Science.gov (United States)

    Bardakova, K. N.; Demina, T. S.; Grebenik, E. A.; Minaev, N. V.; Akopova, T. A.; Bagratashvili, V. N.; Timashev, P. S.

    2018-04-01

    Chitosan-g-oligo (L,L-lactide) copolymer was synthesized through a solvent-free reaction in an extruder. Three-dimensional scaffolds based on photosensitive composition contained the synthetized copolymer were formed by two-photon polymerization. The optimum ratio of components, methods of preparation of photopolymerizable mixtures, parameters of the laser structuring and procedure of washing from unbound crosslinkers have been optimized. Chitosan scaffolds were non-cytotoxic and might therefore be a suitable candidate for treating spinal cord injuries and other neuronal degenerative diseases.

  18. Arching in three-dimensional clogging

    Science.gov (United States)

    Török, János; Lévay, Sára; Szabó, Balázs; Somfai, Ellák; Wegner, Sandra; Stannarius, Ralf; Börzsönyi, Tamás

    2017-06-01

    Arching in dry granular material is a long established concept, however it remains still an open question how three-dimensional orifices clog. We investigate by means of numerical simulations and experimental data how the outflow creates a blocked configuration of particles. We define the concave surface of the clogged dome by two independent methods (geometric and density based). The average shape of the cupola for spheres is almost a hemisphere but individual samples have large holes in the structure indicating a blocked state composed of two-dimensional force chains rather than three-dimensional objects. The force chain structure justifies this assumption. For long particles the clogged configurations display large variations, and in certain cases the empty region reaches a height of 5 hole diameters. These structures involve vertical walls consisting of horizontally placed stable stacking of particles.

  19. Three-dimensional bio-printing.

    Science.gov (United States)

    Gu, Qi; Hao, Jie; Lu, YangJie; Wang, Liu; Wallace, Gordon G; Zhou, Qi

    2015-05-01

    Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.

  20. Three dimensional imaging in cardiac nuclear medicine

    International Nuclear Information System (INIS)

    Torizuka, Kanji; Ishii, Yasushi; Yonekura, Yoshiharu; Yamamoto, Kazutaka; Tamaki, Takeyoshi

    1981-01-01

    Methods to obtain three dimensional images of the heart were reviewed. Gated three dimensional display reconstructed from images using bidirectional collimator, was a useful method to detect akinesis of the heart wall. Tomographic observation of the heart can be carried out by a pinhole collimator to image ischemia with high sensitivity. However the focusing plane must be carefully selected to prevent false positives. In the case of emission CT (ECT), utilization of positron emitters gave a quantitative image without correction, whereas single photon ECT needed the correction due to the absorption of γ-ray. Though the reliability of the images by ECT was high, the time required for data acquisition was much longer than that by a 7 pinhole or bidirectional collimator. (Nakanishi, T.)

  1. Three dimensional transport model for toroidal plasmas

    International Nuclear Information System (INIS)

    Copenhauer, C.

    1980-12-01

    A nonlinear MHD model, developed for three-dimensional toroidal geometries (asymmetric) and for high β (β approximately epsilon), is used as a basis for a three-dimensional transport model. Since inertia terms are needed in describing evolving magnetic islands, the model can calculate transport, both in the transient phase before nonlinear saturation of magnetic islands and afterwards on the resistive time scale. In the β approximately epsilon ordering, the plasma does not have sufficient energy to compress the parallel magnetic field, which allows the Alfven wave to be eliminated in the reduced nonlinear equations, and the model then follows the slower time scales. The resulting perpendicular and parallel plasma drift velocities can be identified with those of guiding center theory

  2. Three dimensional digital imaging of environmental data

    International Nuclear Information System (INIS)

    Nichols, R.L.; Eddy, C.A.

    1991-01-01

    The Environmental Sciences Section (ESS) of the Savannah River Laboratory has recently acquired the computer hardware (Silicon Graphics Personal Iris Workstations) and software (Dynamic Graphics, Interactive Surface and Volume Modeling) to perform three dimensional analysis of hydrogeologic data. Three dimensional digital imaging of environmental data is a powerful technique that can be used to incorporate field, analytical, and modeling results from geologic, hydrologic, ecologic, and chemical studies into a comprehensive model for visualization and interpretation. This report covers the contamination of four different sites of the Savannah River Plant. Each section of this report has a computer graphic display of the concentration of contamination in the groundwater and/or sediments of each site

  3. SNAP - a three dimensional neutron diffusion code

    International Nuclear Information System (INIS)

    McCallien, C.W.J.

    1993-02-01

    This report describes a one- two- three-dimensional multi-group diffusion code, SNAP, which is primarily intended for neutron diffusion calculations but can also carry out gamma calculations if the diffusion approximation is accurate enough. It is suitable for fast and thermal reactor core calculations and for shield calculations. SNAP can solve the multi-group neutron diffusion equations using finite difference methods. The one-dimensional slab, cylindrical and spherical geometries and the two-dimensional case are all treated as simple special cases of three-dimensional geometries. Numerous reflective and periodic symmetry options are available and may be used to reduce the number of mesh points necessary to represent the system. Extrapolation lengths can be specified at internal and external boundaries. (Author)

  4. Three-dimensional Imaging, Visualization, and Display

    CERN Document Server

    Javidi, Bahram; Son, Jung-Young

    2009-01-01

    Three-Dimensional Imaging, Visualization, and Display describes recent developments, as well as the prospects and challenges facing 3D imaging, visualization, and display systems and devices. With the rapid advances in electronics, hardware, and software, 3D imaging techniques can now be implemented with commercially available components and can be used for many applications. This volume discusses the state-of-the-art in 3D display and visualization technologies, including binocular, multi-view, holographic, and image reproduction and capture techniques. It also covers 3D optical systems, 3D display instruments, 3D imaging applications, and details several attractive methods for producing 3D moving pictures. This book integrates the background material with new advances and applications in the field, and the available online supplement will include full color videos of 3D display systems. Three-Dimensional Imaging, Visualization, and Display is suitable for electrical engineers, computer scientists, optical e...

  5. Three-dimensional imaging modalities in endodontics

    Science.gov (United States)

    Mao, Teresa

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome. PMID:25279337

  6. Three-dimensional imaging modalities in endodontics

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Teresa; Neelakantan, Prasanna [Dept. of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai (India)

    2014-09-15

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome.

  7. Three-dimensional imaging modalities in endodontics

    International Nuclear Information System (INIS)

    Mao, Teresa; Neelakantan, Prasanna

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome

  8. THREE DIMENSIONAL GRAPHICAL REPRESENTATION OF QUALITY

    Directory of Open Access Journals (Sweden)

    Vineet V. Kumar

    2014-03-01

    Full Text Available Quality is an important aspect for every firm in modern era of competition. Every product has tough competition in terms of market reach. The factor, which actually makes any product long run in market, is quality and hence quality is the stepping-stone for success of any firm. For everyone meaning of quality is different. We have seen several economists who have defined quality by considering different factors, but what all of them have common in them is Customer satisfaction. Customer satisfaction is the ultimate result of quality. In three-dimensional graphical representation of quality, optimum quality is obtained by using three-dimensional graph by considering some important factors governing quality of any product, limiting factor, and customer satisfaction.

  9. Three dimensional contact/impact methodology

    International Nuclear Information System (INIS)

    Kulak, R.F.

    1987-01-01

    The simulation of three-dimensional interface mechanics between reactor components and structures during static contact or dynamic impact is necessary to realistically evaluate their structural integrity to off-normal loads. In our studies of postulated core energy release events, we have found that significant structure-structure interactions occur in some reactor vessel head closure designs and that fluid-structure interactions occur within the reactor vessel. Other examples in which three-dimensional interface mechanics play an important role are: (1) impact response of shipping casks containing spent fuel, (2) whipping pipe impact on reinforced concrete panels or pipe-to-pipe impact after a pipe break, (3) aircraft crash on secondary containment structures, (4) missiles generated by turbine failures or tornados, and (5) drops of heavy components due to lifting accidents. The above is a partial list of reactor safety problems that require adequate treatment of interface mechanics and are discussed in this paper

  10. Three-dimensional simulation of vortex breakdown

    Science.gov (United States)

    Kuruvila, G.; Salas, M. D.

    1990-01-01

    The integral form of the complete, unsteady, compressible, three-dimensional Navier-Stokes equations in the conservation form, cast in generalized coordinate system, are solved, numerically, to simulate the vortex breakdown phenomenon. The inviscid fluxes are discretized using Roe's upwind-biased flux-difference splitting scheme and the viscous fluxes are discretized using central differencing. Time integration is performed using a backward Euler ADI (alternating direction implicit) scheme. A full approximation multigrid is used to accelerate the convergence to steady state.

  11. Impermeability effects in three-dimensional vesicles

    International Nuclear Information System (INIS)

    Biscari, P; Canevese, S M; Napoli, G

    2004-01-01

    We analyse the effects of the impermeability constraint on the equilibrium shapes of a three-dimensional vesicle hosting a rigid inclusion. A given alteration of the inclusion and/or vesicle parameters leads to shape modifications of different orders of magnitude, when applied to permeable or impermeable vesicles. Moreover, the enclosed-volume constraint wrecks the uniqueness of stationary equilibrium shapes, and gives rise to pear-shaped or stomatocyte-like vesicles

  12. Multiparallel Three-Dimensional Optical Microscopy

    Science.gov (United States)

    Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

    2010-01-01

    Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

  13. Three dimensional analysis of laterally loaded piles

    International Nuclear Information System (INIS)

    Yilmaz, C.

    1987-01-01

    In this study static analysis of laterally loaded pile is studied by the three models. The first model is the beam on discrete elastic springs. This model is analyzed using a flexibility method. The second model is the beam on a two-parameter elastic foundation. This model is analyzed using the linear finite element method. The third model is the finite element model, using the three-dimensional iso-parametric parabolic brick element. Three-dimensional pile group analysis is also performed using elastic constants of single pile obtained by any one of the above analyses. The main objective is to develop computer programs for each model related to single piles and to group analysis. Then, the deflections, rotations, moments, shears, stresses and strains of the single pile are obtained at any arbitrary point. Comparison is made between each model and with other studies such as Poulos 1971, Desai and Appel 1976. In addition, to provide a benchmark of three-dimensional finite element analysis, the Boussinesq problem is analyzed. (orig.)

  14. Three-Dimensional Reconstruction of Sandpile Interiors

    Science.gov (United States)

    Seidler, G. T.

    2001-03-01

    The granular bed, or sandpile, has become one of the condensed matter physicist's favorite systems. In addition to conceptual appeal, the simplest sandpile of monodisperse hard spheres is a valuable model system for understanding powders, liquids, and metallic glasses. Any fundamental approach to the transport and mechanical properties of three-dimensional mesoscale disordered materials must follow from a thorough understanding of their structure. However, in the overwhelming majority of cases, structure measurements have been limited to the mean filling fraction and the structural autocorrelation function. This is particularly unfortunate in the ongoing sandpile renaissance, where some of the most interesting questions concern structure and the relationship between structure and dynamics. I will discuss the combination of synchrotron x-ray microtomography and computer vision algorithms to perform three-dimensional virtual reconstructions of real sandpiles. This technique is rapid and noninvasive, and is applicable to samples large enough to separate bulk and boundary properties. The resulting complete knowledge of structure can be used to calculate otherwise inaccessible correlation functions. I will present results for several measures of the bond-orientational order in three-dimensional sandpiles, including fabric tensors and nematic order parameters.

  15. Three-dimensional deformation of orthodontic brackets

    Science.gov (United States)

    Melenka, Garrett W; Nobes, David S; Major, Paul W

    2013-01-01

    Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201

  16. Three-dimensional deformation of orthodontic brackets.

    Science.gov (United States)

    Melenka, Garrett W; Nobes, David S; Major, Paul W; Carey, Jason P

    2013-01-01

    Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire-bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design.

  17. Reprocessable thermosets for sustainable three-dimensional printing.

    Science.gov (United States)

    Zhang, Biao; Kowsari, Kavin; Serjouei, Ahmad; Dunn, Martin L; Ge, Qi

    2018-05-08

    Among all three-dimensional (3D) printing materials, thermosetting photopolymers claim almost half of the market, and have been widely used in various fields owing to their superior mechanical stability at high temperatures, excellent chemical resistance as well as good compatibility with high-resolution 3D printing technologies. However, once these thermosetting photopolymers form 3D parts through photopolymerization, the covalent networks are permanent and cannot be reprocessed, i.e., reshaped, repaired, or recycled. Here, we report a two-step polymerization strategy to develop 3D printing reprocessable thermosets (3DPRTs) that allow users to reform a printed 3D structure into a new arbitrary shape, repair a broken part by simply 3D printing new material on the damaged site, and recycle unwanted printed parts so the material can be reused for other applications. These 3DPRTs provide a practical solution to address environmental challenges associated with the rapid increase in consumption of 3D printing materials.

  18. Optically controlled three-dimensional assembly of microfabricated building blocks

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Kelemen, Lorand; Palima, Darwin

    2009-01-01

    We demonstrate a system for constructing reconfigurable microstructures using multiple, real-time configurable counterpropagating-beam traps. We optically assemble geometrically complementary microstructures with complex three-dimensional (3D) topologies produced by two-photon polymerization....... This demonstrates utilization of controllable 3D optical traps for building hierarchical structures from microfabricated building blocks. Optical microassembly with translational and tip-tilt control in 3D achieved by dynamic multiple CB traps can potentially facilitate the construction of functional microdevices...... and may also lead to the future realization of optically actuated micromachines. Fabricating morphologically complex microstructures and then optically manipulating these archetypal building blocks can also be used to construct reconfigurable microenvironments that can aid in understanding cellular...

  19. A review of evolution of electrospun tissue engineering scaffold: From two dimensions to three dimensions.

    Science.gov (United States)

    Ngadiman, Nor Hasrul Akhmal; Noordin, M Y; Idris, Ani; Kurniawan, Denni

    2017-07-01

    The potential of electrospinning process to fabricate ultrafine fibers as building blocks for tissue engineering scaffolds is well recognized. The scaffold construct produced by electrospinning process depends on the quality of the fibers. In electrospinning, material selection and parameter setting are among many factors that contribute to the quality of the ultrafine fibers, which eventually determine the performance of the tissue engineering scaffolds. The major challenge of conventional electrospun scaffolds is the nature of electrospinning process which can only produce two-dimensional electrospun mats, hence limiting their applications. Researchers have started to focus on overcoming this limitation by combining electrospinning with other techniques to fabricate three-dimensional scaffold constructs. This article reviews various polymeric materials and their composites/blends that have been successfully electrospun for tissue engineering scaffolds, their mechanical properties, and the various parameters settings that influence the fiber morphology. This review also highlights the secondary processes to electrospinning that have been used to develop three-dimensional tissue engineering scaffolds as well as the steps undertaken to overcome electrospinning limitations.

  20. Three-dimensional micro structured nanocomposite beams by microfluidic infiltration

    International Nuclear Information System (INIS)

    Lebel, L L; Paez, O A; Therriault, D; Aïssa, B; El Khakani, M A

    2009-01-01

    Three-dimensional (3D) micro structured beams reinforced with a single-walled carbon nanotube (C-SWNT)/polymer nanocomposite were fabricated using an approach based on the infiltration of 3D microfluidic networks. The 3D microfluidic network was first fabricated by the direct-write assembly method, which consists of the robotized deposition of fugitive ink filaments on an epoxy substrate, forming thereby a 3D micro structured scaffold. After encapsulating the 3D micro-scaffold structure with an epoxy resin, the fugitive ink was liquefied and removed, resulting in a 3D network of interconnected microchannels. This microfluidic network was then infiltrated by a polymer loaded with C-SWNTs and subsequently cured. Prior to their incorporation in the polymer matrix, the UV-laser synthesized C-SWNTs were purified, functionalized and dispersed into the matrix using a three-roll mixing mill. The final samples consist of rectangular beams having a complex 3D skeleton structure of C-SWNT/polymer nanocomposite fibers, adapted to offer better performance under flexural solicitation. Dynamic mechanical analysis in flexion showed an increase of 12.5% in the storage modulus compared to the resin infiltrated beams. The nanocomposite infiltration of microfluidic networks demonstrated here opens new prospects for the achievement of 3D reinforced micro structures

  1. Three dimensional illustrating - three-dimensional vision and deception of sensibility

    Directory of Open Access Journals (Sweden)

    Anita Gánóczy

    2009-03-01

    Full Text Available The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena of movement parallax, which can be used efficiently in making three-dimensional graphics, the Zöllner- and Corridor-illusion. There are present in this paper the visual elements, which contribute to define a plane two-dimensional image in three-dimension: coherent lines, the covering, the measurement changes, the relative altitude state, the abatement of detail profusion, the shadings and the perspective effects of colors.

  2. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    International Nuclear Information System (INIS)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu

    1989-01-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.)

  3. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu (Hokkaido Univ., Sapporo (Japan). School of Medicine) (and others)

    1989-08-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.).

  4. Three-dimensional instability of standing waves

    Science.gov (United States)

    Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

    2003-12-01

    We investigate the three-dimensional instability of finite-amplitude standing surface waves under the influence of gravity. The analysis employs the transition matrix (TM) approach and uses a new high-order spectral element (HOSE) method for computation of the nonlinear wave dynamics. HOSE is an extension of the original high-order spectral method (HOS) wherein nonlinear wave wave and wave body interactions are retained up to high order in wave steepness. Instead of global basis functions in HOS, however, HOSE employs spectral elements to allow for complex free-surface geometries and surface-piercing bodies. Exponential convergence of HOS with respect to the total number of spectral modes (for a fixed number of elements) and interaction order is retained in HOSE. In this study, we use TM-HOSE to obtain the stability of general three-dimensional perturbations (on a two-dimensional surface) on two classes of standing waves: plane standing waves in a rectangular tank; and radial/azimuthal standing waves in a circular basin. For plane standing waves, we confirm the known result of two-dimensional side-bandlike instability. In addition, we find a novel three-dimensional instability for base flow of any amplitude. The dominant component of the unstable disturbance is an oblique (standing) wave oriented at an arbitrary angle whose frequency is close to the (nonlinear) frequency of the original standing wave. This finding is confirmed by direct long-time simulations using HOSE which show that the nonlinear evolution leads to classical Fermi Pasta Ulam recurrence. For the circular basin, we find that, beyond a threshold wave steepness, a standing wave (of nonlinear frequency Omega) is unstable to three-dimensional perturbations. The unstable perturbation contains two dominant (standing-wave) components, the sum of whose frequencies is close to 2Omega. From the cases we consider, the critical wave steepness is found to generally decrease/increase with increasing radial

  5. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

    International Nuclear Information System (INIS)

    Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

    2016-01-01

    The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds

  6. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

    Energy Technology Data Exchange (ETDEWEB)

    Bergemann, Claudia [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Cornelsen, Matthias [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Quade, Antje [Leibniz-Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany); Laube, Thorsten; Schnabelrauch, Matthias [INNOVENT e.V., Biomaterials Department, Pruessingstrasse 27B, D-07745 Jena (Germany); Rebl, Henrike [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Weißmann, Volker [Institute for Polymer Technologies (IPT) e.V., Alter Holzhafen 19, D-23966 Wismar (Germany); Seitz, Hermann [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Nebe, Barbara, E-mail: barbara.nebe@med.uni-rostock.de [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany)

    2016-02-01

    The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds.

  7. Morphological and surface compositional changes in poly(lactide-co-glycolide) tissue engineering scaffolds upon radio frequency glow discharge plasma treatment

    International Nuclear Information System (INIS)

    Djordjevic, Ivan; Britcher, Leanne G.; Kumar, Sunil

    2008-01-01

    Chemical functionalisation of polymeric scaffolds with functional groups such as amine could provide optimal conditions for loading of signalling biomolecules over the entire volume of the porous scaffolds. Three-dimensional (both surface and bulk) functionlisation of large volume scaffolds is highly desirable, but preferably without any change to the basic morphological, structural and bulk chemical properties of the scaffolds. In this work, we have carried out and compared treatments of poly(lactide-co-glycolide) tissue engineering scaffolds by two methods, that is, a wet chemical method using ethylenediamine and a glow discharge plasma method using heptylamine as a precursor. The samples thus prepared were analysed by scanning electron microscopy and X-ray photoelectron spectroscopy. The plasma treatment generated amide and protonated amine (NH + ) groups which were present in the bulk and on the surface of the scaffold. Amination also occurred for the wet chemical treatments but the structural and chemical integrity were adversely affected

  8. Morphological and surface compositional changes in poly(lactide-co-glycolide) tissue engineering scaffolds upon radio frequency glow discharge plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, Ivan [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia); Britcher, Leanne G. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)], E-mail: Leanne.Britcher@unisa.edu.au; Kumar, Sunil [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)

    2008-01-30

    Chemical functionalisation of polymeric scaffolds with functional groups such as amine could provide optimal conditions for loading of signalling biomolecules over the entire volume of the porous scaffolds. Three-dimensional (both surface and bulk) functionlisation of large volume scaffolds is highly desirable, but preferably without any change to the basic morphological, structural and bulk chemical properties of the scaffolds. In this work, we have carried out and compared treatments of poly(lactide-co-glycolide) tissue engineering scaffolds by two methods, that is, a wet chemical method using ethylenediamine and a glow discharge plasma method using heptylamine as a precursor. The samples thus prepared were analysed by scanning electron microscopy and X-ray photoelectron spectroscopy. The plasma treatment generated amide and protonated amine (NH{sup +}) groups which were present in the bulk and on the surface of the scaffold. Amination also occurred for the wet chemical treatments but the structural and chemical integrity were adversely affected.

  9. 3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

    International Nuclear Information System (INIS)

    Scaffaro, Roberto; Lo Re, Giada; Rigogliuso, Salvatrice; Ghersi, Giulio

    2012-01-01

    We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability. (paper)

  10. 3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

    Science.gov (United States)

    Scaffaro, Roberto; Lo Re, Giada; Rigogliuso, Salvatrice; Ghersi, Giulio

    2012-08-01

    We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability.

  11. Fabrication of three-dimensional micro-nanofiber structures by a novel solution blow spinning device

    Directory of Open Access Journals (Sweden)

    Feng Liang

    2017-02-01

    Full Text Available The fabrication of three-dimensional scaffolds has attracted more attention in tissue engineering. The purpose of this study is to explore a new method for the fabrication of three-dimensional micro-nanofiber structures by combining solution blow spinning and rotating collector. In this study, we successfully fabricated fibers with a minimum diameter of 200 nm and a three-dimensional structure with a maximum porosity of 89.9%. At the same time, the influence of various parameters such as the solvent volatility, the shape of the collector, the feed rate of the solution and the applied gas pressure were studied. It is found that solvent volatility has large effect on the formation of the three-dimensional shape of the structure. The shape of the collector affects the porosity and fiber distribution of the three-dimensional structure. The fiber diameter and fiber uniformity can be controlled by adjusting the solution feed rate and the applied gas pressure. It is feasible to fabricate high-quality three-dimensional micro-nanofiber structure by this new method, which has great potential in tissue engineering.

  12. Large Bone Vertical Augmentation Using a Three-Dimensional Printed TCP/HA Bone Graft: A Pilot Study in Dog Mandible

    OpenAIRE

    Carrel, Jean-Pierre; Wiskott, Anselm; Scherrer, Susanne; Durual, Stéphane

    2016-01-01

    Osteoflux is a three-dimensional printed calcium phosphate porous structure for oral bone augmentation. It is a mechanically stable scaffold with a well-defined interconnectivity and can be readily shaped to conform to the bone bed's morphology

  13. Three-dimensional stereo by photometric ratios

    International Nuclear Information System (INIS)

    Wolff, L.B.; Angelopoulou, E.

    1994-01-01

    We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy

  14. Three-dimensional CT of the mandible

    International Nuclear Information System (INIS)

    Zinreich, S.J.; Price, J.C.; Wang, H.; Ahn, H.S.; Kashima, H.

    1988-01-01

    Seventeen patients with mandibular oblation for facial neoplasia, primary neoplasm, and trauma were evaluated with CT and three-dimensional CT. In eight of these patients, a computerized acrylic model was generated for preoperative planning and postoperative reconstruction. The ramus and body of the mandible were reconstructed with mirror image and fusion techniques. Reconstructions of the anterior mandible were generated from models including the midface, skull based, and residual mandibular fragments. The results are preliminary; however, the authors believe that these represent a powerful new tool and a significant advance in mandibular reconstructive technique, reduced anesthesia time, and the optimized restoration of dental alignment and facial contour

  15. Three-dimensional interpretation of TEM soundings

    Science.gov (United States)

    Barsukov, P. O.; Fainberg, E. B.

    2013-07-01

    We describe the approach to the interpretation of electromagnetic (EM) sounding data which iteratively adjusts the three-dimensional (3D) model of the environment by local one-dimensional (1D) transformations and inversions and reconstructs the geometrical skeleton of the model. The final 3D inversion is carried out with the minimal number of the sought parameters. At each step of the interpretation, the model of the medium is corrected according to the geological information. The practical examples of the suggested method are presented.

  16. Three Dimensional Double Layers in Magnetized Plasmas

    DEFF Research Database (Denmark)

    Jovanovic, D.; Lynov, Jens-Peter; Michelsen, Poul

    1982-01-01

    Experimental results are presented which demonstrate the formation of fully three dimensional double layers in a magnetized plasma. The measurements are performed in a magnetized stationary plasma column with radius 1.5 cm. Double layers are produced by introducing an electron beam with radius 0.......4 cm along the magnetic field from one end of the column. The voltage drop across the double layer is found to be determined by the energy of the incoming electron beam. In general we find that the width of the double layer along the external magnetic field is determined by plasma density and beam...

  17. Three-dimensional flow about penguin wings

    Science.gov (United States)

    Noca, Flavio; Sudki, Bassem; Lauria, Michel

    2012-11-01

    Penguins, contrary to airborne birds, do not need to compensate for gravity. Yet, the kinematics of their wings is highly three-dimensional and seems exceedingly complex for plain swimming. Is such kinematics the result of an evolutionary optimization or is it just a forced adaptation of an airborne flying apparatus to underwater swimming? Some answers will be provided based on flow dynamics around robotic penguin wings. Updates will also be presented on the development of a novel robotic arm intended to simulate penguin swimming and enable novel propulsion devices.

  18. Three-dimensional teletherapy treatment planning

    International Nuclear Information System (INIS)

    Panthaleon van Eck, R.B. van.

    1986-01-01

    This thesis deals with physical/mathematical backgrounds of computerized teletherapy treatment planning. The subjects discussed in this thesis can be subdivided into three main categories: a) Three-dimensional treatment planning. A method is evaluated which can be used for the purpose of simulation and optimization of dose distributions in three dimensions. b) The use of Computed Tomography. The use of patient information obtained from Computed Tomography for the purpose of dose computations is evaluated. c) Dose computational models for photon- and electron beams. Models are evaluated which provide information regarding the way in which the radiation dose is distributed in the patient (viz. is absorbed and/or dispersed). (Auth.)

  19. Creating three-dimensional thermal maps

    CSIR Research Space (South Africa)

    Price

    2011-11-01

    Full Text Available stream_source_info Price_2011.pdf.txt stream_content_type text/plain stream_size 30895 Content-Encoding ISO-8859-1 stream_name Price_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Creating Three...-Dimensional Thermal Maps Mathew Price Cogency cc Cape Town Email: mathew@cogency.co.za Jeremy Green CSIR Centre for Mining Innovation Johannesburg Email: jgreen@csir.co.za John Dickens CSIR Centre for Mining Innovation Johannesburg Email: jdickens...

  20. Three-dimensional cooling of muons

    CERN Document Server

    Vsevolozhskaya, T A

    2000-01-01

    The simultaneous ionization cooling of muon beams in all three - the longitudinal and two transverse - directions is considered in a scheme, based on bent lithium lenses with dipole constituent of magnetic field in them, created by a special configuration of current-carrying rod. An analysis of three-dimensional cooling is performed with the use of kinetic equation method. Results of numerical calculation for a specific beam line configuration are presented together with results of computer simulation using the Moliere distribution to describe the Coulomb scattering and the Vavilov distribution used to describe the ionization loss of energy.

  1. Three-Dimensional Cell Behavior in Microgels

    Science.gov (United States)

    Bhattacharjee, Tapomoy; Palmer, Glyn; Ghivizzani, Steven; Keselowsky, Benjamin; Sawyer, W. Gregory; Angelini, Thomas

    The number of dimensions in which particles can freely move strongly influences the collective behavior that emerges from their individual fluctuations. Thus, in 2D systems of cells in petri-dishes, our growing understanding of collective migration may be insufficient to explain cell behavior in 3D tissues. To study cell behavior in 3D, polymer scaffolds are used. Contemporary designs of 3D cell growth scaffolds enable cell migration and proliferative expansion by incorporating of degradable motifs. Matrix degradation creates space for cells to move and proliferate. However, different cell types and experimental conditions require the design of different scaffolds to optimize degradation with specific cell behaviors. By contrast, liquid like solids made from packed microgels can yield under cell generated stresses, allowing for cell motion without the need for scaffold degradation. Moreover, the use of microgels as 3D culture media allows arranging cells in arbitrary structures, harvesting cells, and delivering drugs and nutrients. Preliminary data describing cell behavior in 3D microgel culture will be presented. This material is based on work supported by the National Science Foundation under Grant No. DMR-1352043.

  2. Three-dimensional radiation treatment planning

    International Nuclear Information System (INIS)

    Mohan, R.

    1989-01-01

    A major aim of radiation therapy is to deliver sufficient dose to the tumour volume to kill the cancer cells while sparing the nearby health organs to prevent complications. With the introduction of devices such as CT and MR scanners, radiation therapy treatment planners have access to full three-dimensional anatomical information to define, simulate, and evaluate treatments. There are a limited number of prototype software systems that allow 3D treatment planning currently in use. In addition, there are more advanced tools under development or still in the planning stages. They require sophisticated graphics and computation equipment, complex physical and mathematical algorithms, and new radiation treatment machines that deliver dose very precisely under computer control. Components of these systems include programs for the identification and delineation of the anatomy and tumour, the definition of radiation beams, the calculation of dose distribution patterns, the display of dose on 2D images and as three dimensional surfaces, and the generation of computer images to verify proper patient positioning in treatment. Some of these functions can be performed more quickly and accurately if artificial intelligence or expert systems techniques are employed. 28 refs., figs

  3. Three-dimensional fluorescence lifetime tomography

    International Nuclear Information System (INIS)

    Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.

    2005-01-01

    Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores

  4. Three-dimensional image signals: processing methods

    Science.gov (United States)

    Schiopu, Paul; Manea, Adrian; Craciun, Anca-Ileana; Craciun, Alexandru

    2010-11-01

    Over the years extensive studies have been carried out to apply coherent optics methods in real-time processing, communications and transmission image. This is especially true when a large amount of information needs to be processed, e.g., in high-resolution imaging. The recent progress in data-processing networks and communication systems has considerably increased the capacity of information exchange. We describe the results of literature investigation research of processing methods for the signals of the three-dimensional images. All commercially available 3D technologies today are based on stereoscopic viewing. 3D technology was once the exclusive domain of skilled computer-graphics developers with high-end machines and software. The images capture from the advanced 3D digital camera can be displayed onto screen of the 3D digital viewer with/ without special glasses. For this is needed considerable processing power and memory to create and render the complex mix of colors, textures, and virtual lighting and perspective necessary to make figures appear three-dimensional. Also, using a standard digital camera and a technique called phase-shift interferometry we can capture "digital holograms." These are holograms that can be stored on computer and transmitted over conventional networks. We present some research methods to process "digital holograms" for the Internet transmission and results.

  5. Three dimensional animated images of anorectal malformations

    International Nuclear Information System (INIS)

    Ueno, Shigeru; Yanagimachi, Noriharu; Muro, Isao; Komiya, Taizo; Yokoyama, Seishichi; Hirakawa, Hitoshi; Tajima, Tomoo; Mitomi, Toshio; Suto, Yasuzo.

    1996-01-01

    Accurate reconstruction of the pelvic structures is a most important factor in obtaining a desirable result after anorectoplasty for a patient with anorectal malformation. Preoperative evaluation of the anatomy is indispensable for choosing an appropriate operative method in each case. To facilitate preoperative evaluation, three dimensional animated images of the pelvic structure of patients with anorectal malformations were constructed by computer graphics based upon tomographic images obtained from magnetic resonance imaging. Axial 1-mm thick images of the pelvic portion were generated with spoiling pulse gradient echo sequences using short repetition times (13 msec TR) and short echo times (6 msec TE) with a flip angle of 25 degrees with the patient in the jack-knife position. Graphic data from MR images were transferred to a graphic work station and processed on it. The skin surface, the ano-rectum, the lower urinary tract and the sphincter musculature were segmented by thresholding images by the signal intensity. Three dimensional images were displayed by surface rendering method using the segmented data of each organ and then animation images of these organs were obtained. The anatomy of each type of anomaly was easily recognized by 3-D visualization, and animation of the pelvic viscera and the sphincter musculature made the images more realistic. Animated images of the musculature were especially useful for simulating surgical procedures and could be helpful for reviewing surgical results. (author)

  6. Three-dimensional analysis of antenna sheaths

    International Nuclear Information System (INIS)

    Myra, J.R.; D'Ippolito, D.A.; Ho, Y.L.

    1996-01-01

    The present work is motivated by the importance of r.f. sheaths in determining the antenna-plasma interaction and the sensitivity of the sheaths to the complicated three-dimensional structure of modern ion cyclotron range of frequency (ICRF) antennas. To analyze r.f. sheaths on the plasma facing regions of the launcher, we first calculate the contact points of the tokamak magnetic field lines on the surface of the antenna Faraday screen and nearby limiters for realistic three-dimensional magnetic flux surface and antenna geometries. Next, the r.f. voltage that can drive sheaths at the contact points is determined and used to assess the resulting sheath power dissipation, r.f.-driven sputtering, and r.f.-induced convective cells (which produce edge profile modification). The calculations are embodied in a computer code, ANSAT (antenna sheath analysis tool), and sample ANSAT runs are shown to highlight the physics- and geometry-dependent characteristics of the r.f. sheaths and their relationship to the antenna design. One use of ANSAT is therefore as a design tool, to assess the strengths and weaknesses of a given design with respect to critical voltage handling and edge plasma interaction issues. Additionally, examples are presented where ANSAT has been useful in the analysis and interpretation of ICRF experiments (orig.)

  7. Comparison of Acute Thrombogenicity for Metallic and Polymeric Bioabsorbable Scaffolds: Magmaris Versus Absorb in a Porcine Arteriovenous Shunt Model.

    Science.gov (United States)

    Waksman, Ron; Lipinski, Michael J; Acampado, Eduardo; Cheng, Qi; Adams, Lila; Torii, Sho; Gai, Jiaxiang; Torguson, Rebecca; Hellinga, David M; Westman, Peter C; Joner, Michael; Zumstein, Philine; Kolodgie, Frank D; Virmani, Renu

    2017-08-01

    A comparison in acute thrombogenicity between the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold and the Absorb bioresorbable vascular scaffold has not been performed. This study assessed acute thrombogenicity of Magmaris compared with Absorb and the Orsiro hybrid drug-eluting stent in a porcine arteriovenous shunt model. An ex vivo porcine carotid jugular arteriovenous shunt was established and connected to SYLGARD tubing containing the Magmaris, Absorb, and Orsiro scaffolds/stents and allowed to run in the shunt for a maximum of 1 hour. Twelve shunts (2 shunt runs per pig) were run comparing the 3 scaffolds in alternating order. Nested generalized linear mixed models were used to compare variables between scaffold groups while adjusting for variability between shunt runs. Confocal fluorescent microscopy costaining CD61/CD42b demonstrated that both Magmaris (3.0%) and Orsiro (4.6%) had less platelet coverage of the total scaffold compared with Absorb (21.8%). Scanning electron microscopy demonstrated significantly less thrombus deposition to Magmaris as a percentage of the total scaffold compared with Absorb (5.0% versus 16.1%, P =0.02). Magmaris had significantly less PM-1-positive neutrophil and CD14-positive monocyte adherence compared with both Orsiro and Absorb. Orsiro had significantly less monocyte deposition compared with Absorb. Despite a similar scaffold strut thickness, the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold was significantly less thrombogenic compared with the Absorb bioresorbable vascular scaffold in an ex vivo porcine arteriovenous shunt model. Further studies are needed to determine whether the reduced thrombogenicity of Magmaris will result in reductions in major cardiovascular events. © 2017 American Heart Association, Inc.

  8. Chitin Scaffolds in Tissue Engineering

    Science.gov (United States)

    Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. PMID:21673928

  9. Three dimensional plastic model of the skull from CT images by using photocurable polymer

    International Nuclear Information System (INIS)

    Goto, Masaaki; Katsuki, Takeshi; Uchida, Yuuki; Ihara, Kouichiro; Noguchi, Nobuhiro

    1992-01-01

    Three dimensional analysis in medicine is increasingly becoming a valuable tool in preoperative planning, educating to students, and explaining to patients. Recently three dimensional reconstruction technology has been coupled with computerized resin hardening processes to create acrylic models from the three dimensional reconstruction data. We have fabricated two anatomical models of the skull by the computer controlled resin hardening device. Three dimensional data were created by the three-dimensional reformation system (TRI). As data entry and storage process, contour of bone tissue is manually drawn from each serial CT photographic image of transverse skull sections. These traces are then input to the frame memory by way of the video camera. The computer stores the X, Y coordinates of points along an outline as it is traced. A depth value into the structure, assigned to each section, provides the Z coordinate, that is, the third dimension. Wire frame image is generated by using the storage data. The final image produced by hidden surface removal and shading is displayed on a full color graphic display monitor. Anatomical resin models were generated by a photo hardening device which is controlled by a minicomputer and three dimensional reconstruction data. He-Cd laser beam (wave length: 325 nm) conducted through the fibers scans the bottom of the monometer liquid surface according to the each CT contour data. The elevator moves up after the polymerization of the liquid has been performed in one slice. This device is suitable for the creation of human anatomical structure because the branched form and hollow model can be made easily. Three dimensional resin models are more useful for simulation surgery, education, and explanation than computer aided three-dimensional images. (author)

  10. Steady, three-dimensional, internally heated convection

    International Nuclear Information System (INIS)

    Schubert, G.; Glatzmaier, G.A.; Travis, B.

    1993-01-01

    Numerical calculations have been carried out of steady, symmetric, three-dimensional modes of convection in internally heated, infinite Prandtl number, Boussinesq fluids at a Rayleigh number of 1.4x10 4 in a spherical shell with inner/outer radius of 0.55 and in a 3x3x1 rectangular box. Multiple patterns of convection occur in both geometries. In the Cartesian geometry the patterns are dominated by cylindrical cold downflows and a broad hot upwelling. In the spherical geometry the patterns consist of cylindrical cold downwellings centered either at the vertices of a tetrahedron or the centers of the faces of a cube. The cold downflow cylinders are immersed in a background of upwelling within which there are cylindrical hot concentrations (plumes) and hot halos around the downflows. The forced hot upflow return plumes of internally heated spherical convection are fundamentally different from the buoyancy-driven plumes of heated from below convection

  11. Exact solutions in three-dimensional gravity

    CERN Document Server

    Garcia-Diaz, Alberto A

    2017-01-01

    A self-contained text, systematically presenting the determination and classification of exact solutions in three-dimensional Einstein gravity. This book explores the theoretical framework and general physical and geometrical characteristics of each class of solutions, and includes information on the researchers responsible for their discovery. Beginning with the physical character of the solutions, these are identified and ordered on the basis of their geometrical invariant properties, symmetries, and algebraic classifications, or from the standpoint of their physical nature, for example electrodynamic fields, fluid, scalar field, or dilaton. Consequently, this text serves as a thorough catalogue on 2+1 exact solutions to the Einstein equations coupled to matter and fields, and on vacuum solutions of topologically massive gravity with a cosmological constant. The solutions are also examined from different perspectives, enabling a conceptual bridge between exact solutions of three- and four-dimensional gravit...

  12. Three-dimensional printing physiology laboratory technology.

    Science.gov (United States)

    Sulkin, Matthew S; Widder, Emily; Shao, Connie; Holzem, Katherine M; Gloschat, Christopher; Gutbrod, Sarah R; Efimov, Igor R

    2013-12-01

    Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories.

  13. Towards microscale electrohydrodynamic three-dimensional printing

    International Nuclear Information System (INIS)

    He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

    2016-01-01

    It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics. (paper)

  14. Three-dimensional hologram display system

    Science.gov (United States)

    Mintz, Frederick (Inventor); Chao, Tien-Hsin (Inventor); Bryant, Nevin (Inventor); Tsou, Peter (Inventor)

    2009-01-01

    The present invention relates to a three-dimensional (3D) hologram display system. The 3D hologram display system includes a projector device for projecting an image upon a display medium to form a 3D hologram. The 3D hologram is formed such that a viewer can view the holographic image from multiple angles up to 360 degrees. Multiple display media are described, namely a spinning diffusive screen, a circular diffuser screen, and an aerogel. The spinning diffusive screen utilizes spatial light modulators to control the image such that the 3D image is displayed on the rotating screen in a time-multiplexing manner. The circular diffuser screen includes multiple, simultaneously-operated projectors to project the image onto the circular diffuser screen from a plurality of locations, thereby forming the 3D image. The aerogel can use the projection device described as applicable to either the spinning diffusive screen or the circular diffuser screen.

  15. Three-dimensional echocardiography in valve disease

    Directory of Open Access Journals (Sweden)

    Cesare Fiorentini

    2009-08-01

    Full Text Available This review covers the role of three-dimensional (3D echocardiography in the diagnosis of heart valve disease. Several factors have contributed to the evolution of this technique, which is currently a simple and routine method: rapid evolution in probe and computer technologies, demonstration that 3D data sets allowed more complete and accurate evaluation of cardiac structures, emerging clinical experience indicating the strong potential particularly in valve diseases, volume and function of the two ventricle measurements and several other fields. This report will review current and future applications of 3D echocardiography in mitral, aortic and tricuspid valve diseases underlying both qualitative (morphologic and quantitative advantages of this technique. (Heart International 2007; 3: 35-41

  16. Towards microscale electrohydrodynamic three-dimensional printing

    Science.gov (United States)

    He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

    2016-02-01

    It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics.

  17. An Introduction of Three-dimensional Grammar

    Directory of Open Access Journals (Sweden)

    Fan Xiao

    2017-12-01

    Full Text Available This paper introduces some key points of Three-dimensional Grammar. As for the structure, it can be distinguished into syntactic structure, semantic structure and pragmatic structure from the perspectives of syntax, semantics and pragmatics. And the same is true with the followings, such as grammatical constituents, grammatical functions, grammatical meanings, grammatical focuses. Sentence types which is called sentence pattern, sentence model and sentence types respectively, and analysis methods. This paper proposes that grammatical researches should be done in accordance with the four principles, that is form and meaning co-verified, static and dynamic co-referenced, structure and function co-testified and description and interpretation co-promoted.

  18. Three-dimensional function photonic crystals

    Science.gov (United States)

    Zhang, Hai-Feng

    2017-11-01

    In this paper, the properties of the photonic band gaps (PBGs) of three-dimensional (3D) function photonic crystals (PCs) are theoretically investigated by a modified plane wave expansion (PWE) method, whose equations for computations are deduced. The configuration of 3D function PCs is the dielectric spheres inserted in the air background with simple-cubic (SC) lattices whose dielectric constants are the functions of space coordinates, which can be realized by the electro-optical or optical Kerr effect in the practice. The influences of the parameter for 3D function PCs on the PBGs also are discussed. The calculated results show that the bandwidths and number of PBGs can be tuned with different distributions of function dielectrics. Compared with the conventional 3D dielectric PCs with SC lattices, the larger and more PBGs can be obtained in the 3D function PCs. Those results provide a new way to design the novel practical devices.

  19. Three-dimensional tori and Arnold tongues

    Energy Technology Data Exchange (ETDEWEB)

    Sekikawa, Munehisa, E-mail: sekikawa@cc.utsunomiya-u.ac.jp [Department of Mechanical and Intelligent Engineering, Utsunomiya University, Utsunomiya-shi 321-8585 (Japan); Inaba, Naohiko [Organization for the Strategic Coordination of Research and Intellectual Property, Meiji University, Kawasaki-shi 214-8571 (Japan); Kamiyama, Kyohei [Department of Electronics and Bioinformatics, Meiji University, Kawasaki-shi 214-8571 (Japan); Aihara, Kazuyuki [Institute of Industrial Science, the University of Tokyo, Meguro-ku 153-8505 (Japan)

    2014-03-15

    This study analyzes an Arnold resonance web, which includes complicated quasi-periodic bifurcations, by conducting a Lyapunov analysis for a coupled delayed logistic map. The map can exhibit a two-dimensional invariant torus (IT), which corresponds to a three-dimensional torus in vector fields. Numerous one-dimensional invariant closed curves (ICCs), which correspond to two-dimensional tori in vector fields, exist in a very complicated but reasonable manner inside an IT-generating region. Periodic solutions emerge at the intersections of two different thin ICC-generating regions, which we call ICC-Arnold tongues, because all three independent-frequency components of the IT become rational at the intersections. Additionally, we observe a significant bifurcation structure where conventional Arnold tongues transit to ICC-Arnold tongues through a Neimark-Sacker bifurcation in the neighborhood of a quasi-periodic Hopf bifurcation (or a quasi-periodic Neimark-Sacker bifurcation) boundary.

  20. Multiscale modeling of three-dimensional genome

    Science.gov (United States)

    Zhang, Bin; Wolynes, Peter

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  1. Three-dimensional reconstruction of CT images

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Toshiaki; Kattoh, Keiichi; Kawakami, Genichiroh; Igami, Isao; Mariya, Yasushi; Nakamura, Yasuhiko; Saitoh, Yohko; Tamura, Koreroku; Shinozaki, Tatsuyo

    1986-09-01

    Computed tomography (CT) has the ability to provide sensitive visualization of organs and lesions. Owing to the nature of CT to be transaxial images, a structure which is greater than a certain size appears as several serial CT images. Consequently each observer must reconstruct those images into a three-dimensional (3-D) form mentally. It has been supposed to be of great use if such a 3-D form can be described as a definite figure. A new computer program has been developed which can produce 3-D figures from the profiles of organs and lesions on CT images using spline curves. The figures obtained through this method are regarded to have practical applications.

  2. Full three-dimensional isotropic transformation media

    International Nuclear Information System (INIS)

    García-Meca, C; Martí, J; Martínez, A; Ortuño, R

    2014-01-01

    We present a method that enables the implementation of full three-dimensional (3D) transformation media with minimized anisotropy. It is based on a special kind of shape-preserving mapping and a subsequent optimization process. For sufficiently smooth transformations, the resulting anisotropy can be neglected, paving the way for practically realizable 3D devices. The method is independent of the considered wave phenomenon and can thus be applied to any field for which a transformational technique exists, such as acoustics or thermodynamics. Full 3D isotropy has an additional important implication for optical transformation media, as it eliminates the need for magnetic materials in many situations. To illustrate the potential of the method, we design 3D counterparts of transformation-based electromagnetic squeezers and bends. (paper)

  3. The Three-Dimensional EIT Wave

    Science.gov (United States)

    Thompson, B. J.; Biesecker, D. A.; Gilbert, H. R.; Lawrence, G. R.; Ofman, L.; Wu, S. T.; Warmuth, A.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    An EIT wave is an impulsive disturbance which has been observed in the EUV, Soft X-ray and white light corona, with corresponding observations in the chromosphere. The effects of these disturbances can be observed across the entire solar disk of the Sun, and throughout the inner heliosphere as well. However, the picture is not complete; observations alone do not establish a complete understanding of the nature of this three-dimensional phenomenon. A number of associated phenomena have been documented, though in most cases causality has not determined. Additionally, it is unclear which factors govern the impulse's ability to affect regions of the corona and heliosphere. We discuss the various observations and the models which provided links between the associated phenomena.

  4. Three-dimensional strutted graphene grown by substrate-free sugar blowing for high-power-density supercapacitors

    Science.gov (United States)

    Wang, Xuebin; Zhang, Yuanjian; Zhi, Chunyi; Wang, Xi; Tang, Daiming; Xu, Yibin; Weng, Qunhong; Jiang, Xiangfen; Mitome, Masanori; Golberg, Dmitri; Bando, Yoshio

    2013-01-01

    Three-dimensional graphene architectures in the macroworld can in principle maintain all the extraordinary nanoscale properties of individual graphene flakes. However, current 3D graphene products suffer from poor electrical conductivity, low surface area and insufficient mechanical strength/elasticity; the interconnected self-supported reproducible 3D graphenes remain unavailable. Here we report a sugar-blowing approach based on a polymeric predecessor to synthesize a 3D graphene bubble network. The bubble network consists of mono- or few-layered graphitic membranes that are tightly glued, rigidly fixed and spatially scaffolded by micrometre-scale graphitic struts. Such a topological configuration provides intimate structural interconnectivities, freeway for electron/phonon transports, huge accessible surface area, as well as robust mechanical properties. The graphene network thus overcomes the drawbacks of presently available 3D graphene products and opens up a wide horizon for diverse practical usages, for example, high-power high-energy electrochemical capacitors, as highlighted in this work. PMID:24336225

  5. Three-dimensional (3D) analysis of the temporomandibular joint

    DEFF Research Database (Denmark)

    Kitai, N.; Kreiborg, S.; Murakami, S.

    Symposium Orthodontics 2001: Where are We Now? Where are We Going?, three-dimensional analysis, temporomandibular joint......Symposium Orthodontics 2001: Where are We Now? Where are We Going?, three-dimensional analysis, temporomandibular joint...

  6. Microfluidic engineered high cell density three-dimensional neural cultures

    Science.gov (United States)

    Cullen, D. Kacy; Vukasinovic, Jelena; Glezer, Ari; La Placa, Michelle C.

    2007-06-01

    Three-dimensional (3D) neural cultures with cells distributed throughout a thick, bioactive protein scaffold may better represent neurobiological phenomena than planar correlates lacking matrix support. Neural cells in vivo interact within a complex, multicellular environment with tightly coupled 3D cell-cell/cell-matrix interactions; however, thick 3D neural cultures at cell densities approaching that of brain rapidly decay, presumably due to diffusion limited interstitial mass transport. To address this issue, we have developed a novel perfusion platform that utilizes forced intercellular convection to enhance mass transport. First, we demonstrated that in thick (>500 µm) 3D neural cultures supported by passive diffusion, cell densities =104 cells mm-3), continuous medium perfusion at 2.0-11.0 µL min-1 improved viability compared to non-perfused cultures (p death and matrix degradation. In perfused cultures, survival was dependent on proximity to the perfusion source at 2.00-6.25 µL min-1 (p 90% viability in both neuronal cultures and neuronal-astrocytic co-cultures. This work demonstrates the utility of forced interstitial convection in improving the survival of high cell density 3D engineered neural constructs and may aid in the development of novel tissue-engineered systems reconstituting 3D cell-cell/cell-matrix interactions.

  7. Study on three dimensional seismic isolation system

    International Nuclear Information System (INIS)

    Morishita, Masaki; Kitamura, Seiji

    2003-01-01

    Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three-dimensional seismic isolation technologies, and the results of this year's study are summarized in the following five aspects. (1) Study on Earthquake Condition for Developing 3-dimensional Base Isolation System. The case study S2 is one of the maximum ground motions, of which the records were investigated up to this time. But a few observed near the fault exceed the case study S2 in the long period domain, depending on the fault length and conditions. Generally it is appropriate that the response spectra ratio (vertical/horizontal) is 0.6. (2) Performance Requirement for 3-dimensional Base Isolation System and Devices. Although the integrity map of main equipment/piping dominate the design criteria for the 3-dimensional base isolation system, the combined integrity map is the same as those of FY 2000, which are under fv=1Hz and over hv=20%. (3) Developing Targets and Schedule for 3-dimensional Isolation Technology. The target items for 3-dimensional base isolation system were rearranged into a table, and developing items to be examined concerning the device were also adjusted. A development plan until FY 2009 was made from the viewpoint of realization and establishment of a design guideline on 3-dimensional base isolation system. (4) Study on 3-dimensional Entire Building Base Isolation System. Three ideas among six ideas that had been proposed in FY2001, i.e., '3-dimensional base isolation system incorporating hydraulic

  8. Clinical significance of three-dimensional sonohysterography

    International Nuclear Information System (INIS)

    Lee, Eun Hye; Lee, Mi Hwa; Lee, Chan; Kim, Jong Wook; Shin, Myung Choel

    1999-01-01

    To evaluate the usefulness of three dimensional sonohysterography (3D SHG) in the evaluation of uterine endometrial and submucosal lesions in comparison with conventional two-dimensional sonohysterography (2D SHG). Our series consisted of 26 patients (mean aged 41 years) who complained of uterine bleeding, menorrhagia, or dysmenorrhea. 2D SHG was performed, and then 3D SHG was done after the volume mode was switched on. Simultaneous display of three perpendicular two-dimensional planes and surface rendering of findings on particular section were obtained. We analyzed whether the endometrium was thickened or not, and the location, size, shape, echogenicity, posterior shadowing, and echogenic rim of the focal lesion. The results were compared with the pathologic findings or MRI. There were submucosal myomas (n=12), intramural myomas (n=2), endometrial polyps (n=7), placental polyp (n=1), and normal endometrial cavities (n=4) on SHG. Nineteen cases were confirmed by pathologic findings or MRI. The results were correlated in 89% (17/19) of the cases. We misdiagnosed 2 cases: focal endometrial hyperplasia and choriocarcinoma were misdiagnosed as endometrial polyp and placental polyp, respectively. Imaging diagnoses were same in the techniques. Comparing with 2D SHG, 3D SHG provided a subjective display of pathologic findings and an additional information about spatial relationship between focal lesion and surroundings.

  9. Clinical significance of three-dimensional sonohysterography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Hye; Lee, Mi Hwa; Lee, Chan; Kim, Jong Wook; Shin, Myung Choel [Pochon Cha University College of Medicine, Pochon (Korea, Republic of)

    1999-12-15

    To evaluate the usefulness of three dimensional sonohysterography (3D SHG) in the evaluation of uterine endometrial and submucosal lesions in comparison with conventional two-dimensional sonohysterography (2D SHG). Our series consisted of 26 patients (mean aged 41 years) who complained of uterine bleeding, menorrhagia, or dysmenorrhea. 2D SHG was performed, and then 3D SHG was done after the volume mode was switched on. Simultaneous display of three perpendicular two-dimensional planes and surface rendering of findings on particular section were obtained. We analyzed whether the endometrium was thickened or not, and the location, size, shape, echogenicity, posterior shadowing, and echogenic rim of the focal lesion. The results were compared with the pathologic findings or MRI. There were submucosal myomas (n=12), intramural myomas (n=2), endometrial polyps (n=7), placental polyp (n=1), and normal endometrial cavities (n=4) on SHG. Nineteen cases were confirmed by pathologic findings or MRI. The results were correlated in 89% (17/19) of the cases. We misdiagnosed 2 cases: focal endometrial hyperplasia and choriocarcinoma were misdiagnosed as endometrial polyp and placental polyp, respectively. Imaging diagnoses were same in the techniques. Comparing with 2D SHG, 3D SHG provided a subjective display of pathologic findings and an additional information about spatial relationship between focal lesion and surroundings.

  10. Bifurcation analysis of a three dimensional system

    Directory of Open Access Journals (Sweden)

    Yongwen WANG

    2018-04-01

    Full Text Available In order to enrich the stability and bifurcation theory of the three dimensional chaotic systems, taking a quadratic truncate unfolding system with the triple singularity equilibrium as the research subject, the existence of the equilibrium, the stability and the bifurcation of the system near the equilibrium under different parametric conditions are studied. Using the method of mathematical analysis, the existence of the real roots of the corresponding characteristic equation under the different parametric conditions is analyzed, and the local manifolds of the equilibrium are gotten, then the possible bifurcations are guessed. The parametric conditions under which the equilibrium is saddle-focus are analyzed carefully by the Cardan formula. Moreover, the conditions of codimension-one Hopf bifucation and the prerequisites of the supercritical and subcritical Hopf bifurcation are found by computation. The results show that the system has abundant stability and bifurcation, and can also supply theorical support for the proof of the existence of the homoclinic or heteroclinic loop connecting saddle-focus and the Silnikov's chaos. This method can be extended to study the other higher nonlinear systems.

  11. Three-dimensional dynamics of protostellar evolution

    International Nuclear Information System (INIS)

    Cook, T.L.

    1977-06-01

    A three-dimensional finite difference numerical methodology was developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity, selected such that the net angular momentum relative to the rotating frame is zero. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric toroids. For low thermal pressures, however, the collapsing cloud is unstable to initial perturbations. The fragmentation of protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to non-axisymmetric perturbations. The detailed evolution of the fragmenting toroid depends upon a non-dimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wavelengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into co-rotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

  12. Three-dimensional dynamics of protostellar evolution

    International Nuclear Information System (INIS)

    Cook, T.L.; Harlow, F.H.

    1978-01-01

    A three-dimensional finite difference numerical methodology has been developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high-speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric ellipsoids. For low thermal pressures, however, the collapsing cloud is unstable to perturbations. The resulting fragmentation of unstable protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to nonaxisymmetric perturbations. The detailed evolution of the fragmentation toroid depends upon a nondimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wave-lengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into corotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

  13. Three dimensional characterization and archiving system

    International Nuclear Information System (INIS)

    Sebastian, R.L.; Clark, R.; Gallman, P.

    1995-01-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D ampersand D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D ampersand D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. Chemical analysis plays a vital role throughout the process of decontamination. Before clean-up operations can begin the site must be characterized with respect to the type and concentration of contaminants, and detailed site mapping must clarify areas of both high and low risk. During remediation activities chemical analysis provides a means to measure progress and to adjust clean-up strategy. Once the clean-up process has been completed the results of chemical analysis will verify that the site is in compliance with federal and local regulations

  14. MORPHOLOGICAL DESCRIPTIONS USING THREE-DIMENSIONAL WAVEFRONTS

    Directory of Open Access Journals (Sweden)

    Jean Serra

    2011-05-01

    Full Text Available The present study deals with the analysis of three-dimensional binary objects whose structure is not obvious nor generally clearly visible. Our approach is illustrated through three examples taken from biological microscopy. In one of our examples, we need to extract the osteocytes contained in sixty confocal sections. The cells are not numerous, but are characterized by long branches, hence they will be separated using a directional wavefront The two other objects are more complex and will be analysed by means of a spherical wavefront In the first case, a kidney of a rat embryo, the tissue grows like a tree, where we want to detect the branches, their extremities,and their spatial arrangement. The wavefront method enables us to define precisely branches and extremities, and gives flexible algorithms. The last example deals with the embryonic growth of the chicken shinbone. The central part of the bone (or shaft is structured as a series of nested cylinders following the same axis, and connected by more or less long bridges. Using wavefronts, we show that it is possible to separate the cylinders,and to extract and count the bridges that connect them.

  15. Multimodal three-dimensional dynamic signature

    Directory of Open Access Journals (Sweden)

    Yury E. Kozlov

    2017-11-01

    Full Text Available Reliable authentication in mobile applications is among the most important information security challenges. Today, we can hardly imagine a person who would not own a mobile device that connects to the Internet. Mobile devices are being used to store large amounts of confidential information, ranging from personal photos to electronic banking tools. In 2009, colleagues from Rice University together with their collaborators from Motorola, proposed an authentication through in-air gestures. This and subsequent work contributing to the development of the method are reviewed in our introduction. At the moment, there exists a version of the gesture-based authentication software available for Android mobile devices. This software has not become widespread yet. One of likely reasons for that is the insufficient reliability of the method, which involves similar to its earlier analogs the use of only one device. Here we discuss the authentication based on the multimodal three-dimensional dynamic signature (MTDS performed by two independent mobile devices. The MTDS-based authentication technique is an advanced version of in-air gesture authentication. We describe the operation of a prototype of MTDS-based authentication, including the main implemented algorithms, as well as some preliminary results of testing the software. We expect that our method can be used in any mobile application, provided a number of additional improvements discussed in the conclusion are made.

  16. Three dimensional image alignment, registration and fusion

    International Nuclear Information System (INIS)

    Treves, S.T.; Mitchell, K.D.; Habboush, I.H.

    1998-01-01

    Combined assessment of three dimensional anatomical and functional images (SPECT, PET, MRI, CT) is useful to determine the nature and extent of lesions in many parts of the body. Physicians principally rely on their spatial sense of mentally re-orient and overlap images obtained with different imaging modalities. Objective methods that enable easy and intuitive image registration can help the physician arrive at more optimal diagnoses and better treatment decisions. This review describes a simple, intuitive and robust image registration approach developed in our laboratory. It differs from most other registration techniques in that it allows the user to incorporate all of the available information within the images in the registration process. This method takes full advantage of the ability of knowledgeable operators to achieve image registration and fusion using an intuitive interactive visual approach. It can register images accurately and quickly without the use of elaborate mathematical modeling or optimization techniques. The method provides the operator with tools to manipulate images in three dimensions, including visual feedback techniques to assess the accuracy of registration (grids, overlays, masks, and fusion of images in different colors). Its application is not limited to brain imaging and can be applied to images from any region in the body. The overall effect is a registration algorithm that is easy to implement and can achieve accuracy on the order of one pixel

  17. Three-Dimensional Printed Thermal Regulation Textiles.

    Science.gov (United States)

    Gao, Tingting; Yang, Zhi; Chen, Chaoji; Li, Yiju; Fu, Kun; Dai, Jiaqi; Hitz, Emily M; Xie, Hua; Liu, Boyang; Song, Jianwei; Yang, Bao; Hu, Liangbing

    2017-11-28

    Space cooling is a predominant part of energy consumption in people's daily life. Although cooling the whole building is an effective way to provide personal comfort in hot weather, it is energy-consuming and high-cost. Personal cooling technology, being able to provide personal thermal comfort by directing local heat to the thermally regulated environment, has been regarded as one of the most promising technologies for cooling energy and cost savings. Here, we demonstrate a personal thermal regulated textile using thermally conductive and highly aligned boron nitride (BN)/poly(vinyl alcohol) (PVA) composite (denoted as a-BN/PVA) fibers to improve the thermal transport properties of textiles for personal cooling. The a-BN/PVA composite fibers are fabricated through a fast and scalable three-dimensional (3D) printing method. Uniform dispersion and high alignment of BN nanosheets (BNNSs) can be achieved during the processing of fiber fabrication, leading to a combination of high mechanical strength (355 MPa) and favorable heat dispersion. Due to the improved thermal transport property imparted by the thermally conductive and highly aligned BNNSs, better cooling effect (55% improvement over the commercial cotton fiber) can be realized in the a-BN/PVA textile. The wearable a-BN/PVA textiles containing the 3D-printed a-BN/PVA fibers offer a promising selection for meeting the personal cooling requirement, which can significantly reduce the energy consumption and cost for cooling the whole building.

  18. Three-dimensional printing for craniomaxillofacial regeneration.

    Science.gov (United States)

    Gaviria, Laura; Pearson, Joseph J; Montelongo, Sergio A; Guda, Teja; Ong, Joo L

    2017-10-01

    Craniomaxillofacial injuries produce complex wound environments involving various tissue types and treatment strategies. In a clinical setting, care is taken to properly irrigate and stabilize the injury, while grafts are molded in an attempt to maintain physiological functionality and cosmesis. This often requires multiple surgeries and grafts leading to added discomfort, pain and financial burden. Many of these injuries can lead to disfigurement and resultant loss of system function including mastication, respiration, and articulation, and these can lead to acute and long-term psychological impact on the patient. A main causality of these issues is the lack of an ability to spatially control pre-injury morphology while maintaining shape and function. With the advent of additive manufacturing (three-dimensional printing) and its use in conjunction with biomaterial regenerative strategies and stem cell research, there is an increased potential capacity to alleviate such limitations. This review focuses on the current capabilities of additive manufacturing platforms, completed research and potential for future uses in the treatment of craniomaxillofacial injuries, with an in-depth discussion of regeneration of the periodontal complex and teeth.

  19. Three-dimensional supersonic vortex breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.

    1993-01-01

    Three-dimensional supersonic vortex-breakdown problems in bound and unbound domains are solved. The solutions are obtained using the time-accurate integration of the unsteady, compressible, full Navier-Stokes (NS) equations. The computational scheme is an implicit, upwind, flux-difference splitting, finite-volume scheme. Two vortex-breakdown applications are considered in the present paper. The first is for a supersonic swirling jet which is issued from a nozzle into a supersonic uniform flow at a lower Mach number than that of the swirling jet. The second is for a supersonic swirling flow in a configured circular duct. In the first application, an extensive study of the effects of grid fineness, shape and grid-point distribution on the vortex breakdown is presented. Four grids are used in this study and they show a substantial dependence of the breakdown bubble and shock wave on the grid used. In the second application, the bubble-type and helix-type vortex breakdown have been captured.

  20. Three-dimensional laparoscopy: Principles and practice

    Directory of Open Access Journals (Sweden)

    Rakesh Y Sinha

    2017-01-01

    Full Text Available The largest challenge for laparoscopic surgeons is the eye–hand coordination within a three-dimensional (3D scene observed on a 2D display. The 2D view on flat screen laparoscopy is cerebrally intensive. The loss of binocular vision on a 2D display causes visual misperceptions, mainly loss of depth perception and adds to the surgeon's fatigue. This compromises the safety of laparoscopy. The 3D high-definition view with great depth perception and tactile feedback makes laparoscopic surgery more acceptable, safe and cost-effective. It improves surgical precision and hand–eye coordination, conventional and all straight stick instruments can be used, capital expenditure is less and recurring cost and annual maintenance cost are less. In this article, we have discussed the physics of 3D laparoscopy, principles of depth perception, and the different kinds of 3D systems available for laparoscopy. We have also discussed our experience of using 3D laparoscopy in over 2000 surgeries in the last 4 years.

  1. Three dimensional characterization and archiving system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, R.L.; Clark, R.; Gallman, P. [Coleman Research Corp., Springfield, VA (United States)] [and others

    1995-10-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. The 3D-ICAS system robotically conveys a multisensor probe near the surface to be inspected. The sensor position and orientation are monitored and controlled by Coherent laser radar (CLR) tracking. The ICAS fills the need for high speed automated organic analysis by means of gas chromatography-mass spectrometry sensors, and also by radionuclide sensors which combines alpha, beta, and gamma counting.

  2. Three dimensional characterization and archiving system

    International Nuclear Information System (INIS)

    Sebastian, R.L.; Clark, R.; Gallman, P.

    1996-01-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D and D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D and D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. The 3D-ICAS system robotically conveys a multisensor probe near the surfaces to be inspected. The sensor position and orientation are monitored and controlled using coherent laser radar (CLR) tracking. The CLR also provides 3D facility maps which establish a 3D world view within which the robotic sensor system can operate

  3. Three-dimensional RAMA fluence methodology benchmarking

    International Nuclear Information System (INIS)

    Baker, S. P.; Carter, R. G.; Watkins, K. E.; Jones, D. B.

    2004-01-01

    This paper describes the benchmarking of the RAMA Fluence Methodology software, that has been performed in accordance with U. S. Nuclear Regulatory Commission Regulatory Guide 1.190. The RAMA Fluence Methodology has been developed by TransWare Enterprises Inc. through funding provided by the Electric Power Research Inst., Inc. (EPRI) and the Boiling Water Reactor Vessel and Internals Project (BWRVIP). The purpose of the software is to provide an accurate method for calculating neutron fluence in BWR pressure vessels and internal components. The Methodology incorporates a three-dimensional deterministic transport solution with flexible arbitrary geometry representation of reactor system components, previously available only with Monte Carlo solution techniques. Benchmarking was performed on measurements obtained from three standard benchmark problems which include the Pool Criticality Assembly (PCA), VENUS-3, and H. B. Robinson Unit 2 benchmarks, and on flux wire measurements obtained from two BWR nuclear plants. The calculated to measured (C/M) ratios range from 0.93 to 1.04 demonstrating the accuracy of the RAMA Fluence Methodology in predicting neutron flux, fluence, and dosimetry activation. (authors)

  4. Three-Dimensional Printed Graphene Foams.

    Science.gov (United States)

    Sha, Junwei; Li, Yilun; Villegas Salvatierra, Rodrigo; Wang, Tuo; Dong, Pei; Ji, Yongsung; Lee, Seoung-Ki; Zhang, Chenhao; Zhang, Jibo; Smith, Robert H; Ajayan, Pulickel M; Lou, Jun; Zhao, Naiqin; Tour, James M

    2017-07-25

    An automated metal powder three-dimensional (3D) printing method for in situ synthesis of free-standing 3D graphene foams (GFs) was successfully modeled by manually placing a mixture of Ni and sucrose onto a platform and then using a commercial CO 2 laser to convert the Ni/sucrose mixture into 3D GFs. The sucrose acted as the solid carbon source for graphene, and the sintered Ni metal acted as the catalyst and template for graphene growth. This simple and efficient method combines powder metallurgy templating with 3D printing techniques and enables direct in situ 3D printing of GFs with no high-temperature furnace or lengthy growth process required. The 3D printed GFs show high-porosity (∼99.3%), low-density (∼0.015g cm -3 ), high-quality, and multilayered graphene features. The GFs have an electrical conductivity of ∼8.7 S cm -1 , a remarkable storage modulus of ∼11 kPa, and a high damping capacity of ∼0.06. These excellent physical properties of 3D printed GFs indicate potential applications in fields requiring rapid design and manufacturing of 3D carbon materials, for example, energy storage devices, damping materials, and sound absorption.

  5. Effect of biomimetic 3D environment of an injectable polymeric scaffold on MG-63 osteoblastic-cell response

    International Nuclear Information System (INIS)

    Verma, Shalini; Kumar, Neeraj

    2010-01-01

    Solid PLGA microspheres were fabricated and characterized in terms of their in vitro degradation behaviour. Microsphere scaffolds were then modified covalently by P-15 (GTPGPQGIAGQRGVV) to obtain a 3D bioactive collagen surrogate matrix for bone filling applications. These scaffolds were characterized for surface topography, hydrophilicity and evaluated for their effect on osteoblastic activity of MG-63 cell line vis-a-vis 2D monolayer culture. AFM and contact angle experiments indicated enhanced nano-level roughness and hydrophilicity on P-15 modification. Modified scaffolds showed enhanced cell attachment, proliferation, extracellular matrix formation, mineralization and collagen type-I expression when compared to unmodified microspheres, prerequisite for bone filling applications. On long term in vitro cell culture, however, decreased cell viability was observed which may be attributed to the acidic microenvironment generated due to polymer degradation and reduction in nutrient diffusion through the copious ECM formed in 3D scaffolds. Though a higher cell count could be obtained in 2D monolayer cell culture, it was overshadowed by weak cell attachment, poor phenotypic characteristics, decreased cell viability and low mineralization levels, over 28 day cell culture studies. Results indicate that P-15 modified microsphere scaffolds may provide a natural, biomimetic 3D environment and may be successfully exploited for non-invasive bone filling applications.

  6. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Don; Park, Chang Seo [Dept. of Dental Radiology, College of Dentistry, Yensei University, Seoul (Korea, Republic of); Yoo, Sun Kook; Lee, Kyoung Sang [Dept. of Medical Engineering, College of Medicine, Yensei University, Seoul (Korea, Republic of)

    1998-08-15

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  7. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    International Nuclear Information System (INIS)

    Kim, Hyun Don; Park, Chang Seo; Yoo, Sun Kook; Lee, Kyoung Sang

    1998-01-01

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  8. Technical Development of Slurry Three-Dimensional Printer

    Science.gov (United States)

    Jiang, Cho-Pei; Hsu, Huang-Jan; Lee, Shyh-Yuan

    2017-09-01

    The aim of this paper is to review the technical development of slurry three-dimensional printer (3DP) which based on photo-polymerization and constrained surface method. Basically, slurry consists of ceramic powder, resin and photo-initiator. The light engines for solidifying the photo-curable slurry can be classified as laser, liquid crystal panel (LCD), digital light processing (DLP). The slurry can be reacted and solidified by selective ray according to the reaction spectrum of photo-initiator. Ceramic powder used in this study is zirconia oxide. Experimental results show that ceramic particle size affects the viscosity of slurry severely resulting in low accuracy and the occurrence of micro crack in the layer casting procedure. Therefore, the effect of particle size on the curability and accuracy of built green part is discussed. A single dental crown is proposed to be fabricated by these three light engines as a benchmark for comparison. In addition, the cost and the limitation are compared in the aspect of dental crown fabrication. Consequently, the lowest cost is LCD-type slurry 3DP system. DLP-type slurry 3DP can produce green body with the fastest fabrication time. The volumetric error of sintered part that made by these three fabrication methods is similar because the composition of slurry is the same.

  9. Three-Dimensional Printing of Bisphenol A-Free Polycarbonates.

    Science.gov (United States)

    Zhu, Wei; Pyo, Sang-Hyun; Wang, Pengrui; You, Shangting; Yu, Claire; Alido, Jeffrey; Liu, Justin; Leong, Yew; Chen, Shaochen

    2018-02-14

    Polycarbonates are widely used in food packages, drink bottles, and various healthcare products such as dental sealants and tooth coatings. However, bisphenol A (BPA) and phosgene used in the production of commercial polycarbonates pose major concerns to public health safety. Here, we report a green pathway to prepare BPA-free polycarbonates (BFPs) by thermal ring-opening polymerization and photopolymerization. Polycarbonates prepared from two cyclic carbonates in different mole ratios demonstrated tunable mechanical stiffness, excellent thermal stability, and high optical transparency. Three-dimensional (3D) printing of the new BFPs was demonstrated using a two-photon laser direct writing system and a rapid 3D optical projection printer to produce structures possessing complex high-resolution geometries. Seeded C3H10T1/2 cells also showed over 95% viability with potential applications in biological studies. By combining biocompatible BFPs with 3D printing, novel safe and high-performance biomedical devices and healthcare products could be developed with broad long-term benefits to society.

  10. Panoramic three-dimensional CT imaging

    International Nuclear Information System (INIS)

    Kawamata, Akitoshi; Fujishita, Masami

    1998-01-01

    Panoramic radiography is a unique projection technique for producing a single image of both maxillary and mandibular arches and many other anatomical structures. To obtain a similar panoramic image without panoramic radiography system, a modified three-dimensional (3D) CT imaging technique was designed. A set of CT slice image data extending from the chin to the orbit was used for 3D reconstruction. The CT machine used in this study was the X-Vision (TOSHIBA, Japan). The helical scan technique was used. The slice thickness of reconstructed image was one or 1.5 mm. The occlusal plane or Frankfort horizontal (FH) plane was used as the reference line. The resultant slice image data was stored on a magnetic optical disk and then used to create panoramic 3D-CT images on a Macintosh computer systems (Power Macintosh 8600/250, Apple Computer Inc., USA). To create the panoramic 3D-CT image, the following procedure was designed: Design a curved panoramic 3D-CT imaging layer using the imaging layer and the movement of the x-ray beam in panoramic radiography system as a template; Cut this imaging layer from each slice image, then the trimmed image was transformed to a rectangular layer using the ''still image warping'' special effect in the Elastic Reality special effects system (Elastic Reality Inc., USA); Create panoramic 3D-CT image using the Voxel View (Vital Images Inc., USA) rendering system and volume rendering technique. Although the image quality was primitive, a panoramic view of maxillofacial region was obtained by this technique. (author)

  11. Airway branching morphogenesis in three dimensional culture

    Directory of Open Access Journals (Sweden)

    Gudjonsson Thorarinn

    2010-11-01

    Full Text Available Abstract Background Lungs develop from the fetal digestive tract where epithelium invades the vascular rich stroma in a process called branching morphogenesis. In organogenesis, endothelial cells have been shown to be important for morphogenesis and the maintenance of organ structure. The aim of this study was to recapitulate human lung morphogenesis in vitro by establishing a three dimensional (3D co-culture model where lung epithelial cells were cultured in endothelial-rich stroma. Methods We used a human bronchial epithelial cell line (VA10 recently developed in our laboratory. This cell line cell line maintains a predominant basal cell phenotype, expressing p63 and other basal markers such as cytokeratin-5 and -14. Here, we cultured VA10 with human umbilical vein endothelial cells (HUVECs, to mimic the close interaction between these cell types during lung development. Morphogenesis and differentiation was monitored by phase contrast microscopy, immunostainings and confocal imaging. Results We found that in co-culture with endothelial cells, the VA10 cells generated bronchioalveolar like structures, suggesting that lung epithelial branching is facilitated by the presence of endothelial cells. The VA10 derived epithelial structures display various complex patterns of branching and show partial alveolar type-II differentiation with pro-Surfactant-C expression. The epithelial origin of the branching VA10 colonies was confirmed by immunostaining. These bronchioalveolar-like structures were polarized with respect to integrin expression at the cell-matrix interface. The endothelial-induced branching was mediated by soluble factors. Furthermore, fibroblast growth factor receptor-2 (FGFR-2 and sprouty-2 were expressed at the growing tips of the branching structures and the branching was inhibited by the FGFR-small molecule inhibitor SU5402. Discussion In this study we show that a human lung epithelial cell line can be induced by endothelial cells to

  12. [Precision of three-dimensional printed brackets].

    Science.gov (United States)

    Zhang, D; Wang, L C; Zhou, Y H; Liu, X M; Li, J

    2017-08-18

    This study was based on digital orthodontic diagnosis work flow for indirect bonding transfer tray model design and three-dimensional (3D) printing, and the aim of this paper was to inspect the dimensional accuracyof 3D printed brackets, which is the foundation of the follow up work and hoped that will illuminate the clinical application of the digital orthodontics work flow. The samples which consisted of 14 cases of patients with malocclusion from Department of Orthodontics Peking University were selected, including 8 cases with tooth extraction and 6 cases without tooth extraction. All the 14 patients were taken intra-oral scan (Trios 3Shape, Denmark) and cone-beam computed tomography (CBCT, NewTom 3G volumetric scanner, Aperio Service,Italy)shooting after periodontal treatment. STL data and DICOM data were obtained from intraoral scans and CBCT images.Data segmentation, registration, fusion, automatic tooth arrangement, virtual positioning of orthodontic appliance and conversion the coordinates of malocclusion model were all done with self-programming software. The data of 3D printing model with brackets on it were output finally and printed out with EDEN260V (Objet Geometries, Israel) to make indirect bonding transfer tray. Digital vernier caliper was used to measure the length and width of upper and lower left brackets and buccal tubes on those 3D models after removal of surrounding supporting material by ultrasonic vibration and water-spray. Intra-examiner reliability was assessed by using intra-class correlation coefficients (ICC), and one-sample T test was used to compare the measurements with the standard dimensional data of the brackets. There were significant differences which range in 0.04-0.17 mm between the 13 items out of the 19 measurement items. Except for the length of the lower left premolars'brackets, mean values of the other items were greater than the test value. Although the measurement results in the width of brackets and the width and

  13. The Three-dimensional Digital Factory for Shipbuilding Technology Research

    Directory of Open Access Journals (Sweden)

    Xu Wei

    2016-01-01

    Full Text Available The three-dimensional digital factory technology research is the hotspot in shipbuilding recently. The three-dimensional digital factory technology not only focus on design the components of the product, but also discuss on the simulation and analyses of the production process.Based on the three-dimensional model, the basic data layer, application control layer and the presentation layer of hierarchical structure are established in the three-dimensional digital factory of shipbuilding in this paper. And the key technologies of three-dimensional digital factory of shipbuilding are analysed. Finally, a case study is applied and the results show that the three-dimensional digital factory will play an important role in the future.

  14. Construction of a Three-Dimensional in vitro skin model on polycaprolactone fibers.

    Science.gov (United States)

    Liu, Qi; Zhang, Ru-Zhi; Xu, Bin

    2017-05-16

    To observe the morphological characteristics and the biological properties of human epidermal cells when cultured at an air-liquid interface in polycaprolactone (PCL) fibers as a three-dimensional scaffold for tissue engineering. In this study, the melanocytes and keratinocytes were obtained from human scalp skin, seeded onto a PCL film, and cocultured for 2 weeks to construct a three-dimensional (3D) skin model. The cells were then characterized by hematoxylin and eosin (H&E) staining, by immunohistochemical staining with antibodies to cytokeratin 15 (CK15), Ki-67, CD34, CD200 and HMB45 and by transmission electron microscopy. Keratinocytes and melanocytes grew well in the co-culture system. Hematoxylin and eosin staining revealed that the cells adhered to the PCLfiber scaffold well, the keratinocyte layer became a multilayered concentric structure and the surface became distinctly keratinized at the air-liquid interface. Immunohistochemical analyses exhibited a scattered distribution of cells expressing CK15, CD34, CD200, Ki-67 and/or HMB45. Transmission electron microscopy revealed that the keratinocytes contained a number of keratin fibrils and membrane-coated granules. The PCL scaffold has excellent adhesiveness and biocompatibility with human epidermal cells, and is suitable for constructing 3D skin models for tissue engineering in the future.

  15. Three-dimensional reconstruction of the biliary tract using spiral computed tomography. Three-dimensional cholangiography

    International Nuclear Information System (INIS)

    Gon, Masanori; Ogura, Norihiro; Uetsuji, Shouji; Ueyama, Yasuo

    1995-01-01

    In this study, 310 patients with benign biliary diseases, 20 with gallbladder cancer, and 8 with biliary tract carcinoma underwent spiral CT (SCT) scanning at cholangiography. Depiction rate of the shape of the conjunction site of the gallbladder and biliary tract was 27.5% by conventional intravenous cholangiography (DIC), 92.5% by ERC, and 90.0% by DIC-SCT. Abnormal cystic duct course was admitted in 14.1%. Multiplanar reconstruction by DIC-SCT enabled identification of the common bile duct and intrahepatic bile duct stone. Three-dimensional reconstruction of DIC-SCT was effective in evaluating obstruction of the anastomosis or passing condition of after hepatico-jejunostomy. Two-dimensional SCT images through PTCD tube enabled degree of hepatic invasion in bile duct cancer, and three-dimensional images were useful in grasping the morphology of the bile duct branches near the obstruction site. DIC-SCT is therefore considered a useful procedure as non-invasive examination of bile duct lesions. (S.Y.)

  16. Femtosecond laser three-dimensional micro- and nanofabrication

    Energy Technology Data Exchange (ETDEWEB)

    Sugioka, Koji, E-mail: ksugioka@riken.jp [RIKEN Center for Advanced Photonics, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Cheng, Ya, E-mail: ya.cheng@siom.ac.cn [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

    2014-12-15

    The rapid development of the femtosecond laser has revolutionized materials processing due to its unique characteristics of ultrashort pulse width and extremely high peak intensity. The short pulse width suppresses the formation of a heat-affected zone, which is vital for ultrahigh precision fabrication, whereas the high peak intensity allows nonlinear interactions such as multiphoton absorption and tunneling ionization to be induced in transparent materials, which provides versatility in terms of the materials that can be processed. More interestingly, irradiation with tightly focused femtosecond laser pulses inside transparent materials makes three-dimensional (3D) micro- and nanofabrication available due to efficient confinement of the nonlinear interactions within the focal volume. Additive manufacturing (stereolithography) based on multiphoton absorption (two-photon polymerization) enables the fabrication of 3D polymer micro- and nanostructures for photonic devices, micro- and nanomachines, and microfluidic devices, and has applications for biomedical and tissue engineering. Subtractive manufacturing based on internal modification and fabrication can realize the direct fabrication of 3D microfluidics, micromechanics, microelectronics, and photonic microcomponents in glass. These microcomponents can be easily integrated in a single glass microchip by a simple procedure using a femtosecond laser to realize more functional microdevices, such as optofluidics and integrated photonic microdevices. The highly localized multiphoton absorption of a tightly focused femtosecond laser in glass can also induce strong absorption only at the interface of two closely stacked glass substrates. Consequently, glass bonding can be performed based on fusion welding with femtosecond laser irradiation, which provides the potential for applications in electronics, optics, microelectromechanical systems, medical devices, microfluidic devices, and small satellites. This review paper

  17. Clinical Application of Three-Dimensional Printing Technology in Craniofacial Plastic Surgery

    OpenAIRE

    Choi, Jong Woo; Kim, Namkug

    2015-01-01

    Three-dimensional (3D) printing has been particularly widely adopted in medical fields. Application of the 3D printing technique has even been extended to bio-cell printing for 3D tissue/organ development, the creation of scaffolds for tissue engineering, and actual clinical application for various medical parts. Of various medical fields, craniofacial plastic surgery is one of areas that pioneered the use of the 3D printing concept. Rapid prototype technology was introduced in the 1990s to m...

  18. New method for solving three-dimensional Schroedinger equation

    International Nuclear Information System (INIS)

    Melezhik, V.S.

    1990-01-01

    The method derived recently for solving a multidimensional scattering problem is applied to a three-dimensional Schroedinger equation. As compared with direct three-dimensional calculations of finite elements and finite differences, this approach gives sufficiently accurate upper and lower approximations to the helium-atom binding energy, which demonstrates its efficiency. 15 refs.; 1 fig.; 2 tabs

  19. Three-dimensional low-energy topological invariants

    International Nuclear Information System (INIS)

    Bakalarska, M.; Broda, B.

    2000-01-01

    A description of the one-loop approximation formula for the partition function of a three-dimensional abelian version of the Donaldson-Witten theory is proposed. The one-loop expression is shown to contain such topological invariants of a three-dimensional manifold M like the Reidemeister-Ray-Singer torsion τ R and Betti numbers. (orig.)

  20. Collapse in a forced three-dimensional nonlinear Schrodinger equation

    DEFF Research Database (Denmark)

    Lushnikov, P.M.; Saffman, M.

    2000-01-01

    We derive sufficient conditions for the occurrence of collapse in a forced three-dimensional nonlinear Schrodinger equation without dissipation. Numerical studies continue the results to the case of finite dissipation.......We derive sufficient conditions for the occurrence of collapse in a forced three-dimensional nonlinear Schrodinger equation without dissipation. Numerical studies continue the results to the case of finite dissipation....

  1. Three-dimensional plasma equilibrium near a separatrix

    International Nuclear Information System (INIS)

    Reiman, A.H.; Pomphrey, N.; Boozer, A.H.

    1988-08-01

    The limiting behavior of a general three-dimensional MHD equilibrium near a separatrix is calculated explicitly. No expansions in β or assumptions about island widths are made. Implications of the results for the numerical calculation of such equilibria, are discussed, as well as for issues concerning the existence of three-dimensional MHD equilibria. 16 refs., 2 figs

  2. Cell factory-derived bioactive molecules with polymeric cryogel scaffold enhance the repair of subchondral cartilage defect in rabbits.

    Science.gov (United States)

    Gupta, Ankur; Bhat, Sumrita; Chaudhari, Bhushan P; Gupta, Kailash C; Tägil, Magnus; Zheng, Ming Hao; Kumar, Ashok; Lidgren, Lars

    2017-06-01

    We have explored the potential of cell factory-derived bioactive molecules, isolated from conditioned media of primary goat chondrocytes, for the repair of subchondral cartilage defects. Enzyme-linked immunosorbent assay (ELISA) confirms the presence of transforming growth factor-β1 in an isolated protein fraction (12.56 ± 1.15 ng/mg protein fraction). These bioactive molecules were used alone or with chitosan-agarose-gelatin cryogel scaffolds, with and without chondrocytes, to check whether combined approaches further enhance cartilage repair. To evaluate this, an in vivo study was conducted on New Zealand rabbits in which a subchondral defect (4.5 mm wide × 4.5 mm deep) was surgically created. Starting after the operation, bioactive molecules were injected at the defect site at regular intervals of 14 days. Histopathological analysis showed that rabbits treated with bioactive molecules alone had cartilage regeneration after 4 weeks. However, rabbits treated with bioactive molecules along with scaffolds, with or without cells, showed cartilage formation after 3 weeks; 6 weeks after surgery, the cartilage regenerated in rabbits treated with either bioactive molecules alone or in combinations showed morphological similarities to native cartilage. No systemic cytotoxicity or inflammatory response was induced by any of the treatments. Further, ELISA was done to determine systemic toxicity, which showed no difference in concentration of tumour necrosis factor-α in blood serum, before or after surgery. In conclusion, intra-articular injection with bioactive molecules alone may be used for the repair of subchondral cartilage defects, and bioactive molecules along with chondrocyte-seeded scaffolds further enhance the repair. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  3. Three dimensional periodic foundations for base seismic isolation

    International Nuclear Information System (INIS)

    Yan, Y; Mo, Y L; Cheng, Z; Shi, Z; Menq, F; Tang, Y

    2015-01-01

    Based on the concept of phononic crystals, periodic foundations made of periodic materials are investigated in this paper. The periodic foundations can provide low frequency band gaps, which cover the main frequency ranges of seismic waves. Therefore, the periodic foundations are able to protect the upper structures during earthquake events. In this paper, the basic theory of three dimensional periodic foundations is studied and the finite element method was used to conduct the sensitivity study. A simplified three-dimensional periodic foundation with a superstructure was tested in the field and the feasibility of three dimensional periodic foundations was proved. The test results showed that the response of the upper structure with the three dimensional periodic foundation was reduced under excitation waves with the main frequency falling in the attenuation zones. The finite element analysis results are consistent with the experimental data, indicating that three dimensional periodic foundations are a feasible way of reducing seismic vibrations. (paper)

  4. Subcritical CO{sub 2} sintering of microspheres of different polymeric materials to fabricate scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Bhamidipati, Manjari; Sridharan, BanuPriya [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Scurto, Aaron M. [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS (United States); Detamore, Michael S., E-mail: detamore@ku.edu [Bioengineering Graduate Program, University of Kansas, Lawrence, KS (United States); Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS (United States)

    2013-12-01

    The aim of this study was to use CO{sub 2} at sub-critical pressures as a tool to sinter 3D, macroporous, microsphere-based scaffolds for bone and cartilage tissue engineering. Porous scaffolds composed of ∼ 200 μm microspheres of either poly(lactic-co-glycolic acid) (PLGA) or polycaprolactone (PCL) were prepared using dense phase CO{sub 2} sintering, which were seeded with rat bone marrow mesenchymal stromal cells (rBMSCs), and exposed to either osteogenic (PLGA, PCL) or chondrogenic (PLGA) conditions for 6 weeks. Under osteogenic conditions, the PLGA constructs produced over an order of magnitude more calcium than the PCL constructs, whereas the PCL constructs had far superior mechanical and structural integrity (125 times stiffer than PLGA constructs) at week 6, along with twice the cell content of the PLGA constructs. Chondrogenic cell performance was limited in PLGA constructs, perhaps as a result of the polymer degradation rate being too high. The current study represents the first long-term culture of CO{sub 2}-sintered microsphere-based scaffolds, and has established important thermodynamic differences in sintering between the selected formulations of PLGA and PCL, with the former requiring adjustment of pressure only, and the latter requiring the adjustment of both pressure and temperature. Based on more straightforward sintering conditions and more favorable cell performance, PLGA may be the material of choice for microspheres in a CO{sub 2} sintering application, although a different PLGA formulation with the encapsulation of growth factors, extracellular matrix-derived nanoparticles, and/or buffers in the microspheres may be advantageous for achieving a more superior cell performance than observed here. - Highlights: • The first long-term culture of CO{sub 2}-sintered microsphere-based scaffolds. • Established important thermodynamic differences between sintering PLGA and PCL. • PCL sintering with CO{sub 2} required manipulation of both

  5. Development of PVA/gelatin nanofibrous scaffolds for Tissue Engineering via electrospinning

    Science.gov (United States)

    Perez-Puyana, V.; Jiménez-Rosado, M.; Romero, A.; Guerrero, A.

    2018-03-01

    The electrospinning process is an emerging and relatively easy technique to prepare three-dimensional matrices with micro- and nanofibers. To achieve it, aqueous polymer solutions from synthetic or natural polymers are used. PVA was selected as polymer and gelatin because of its biocompatibility and biodegradability. A complete characterization of the polymeric solutions (density, surface tension, etc) was previously performed. Subsequently, a standard electrospinning process (15 kV, 0.4 ml h-1 and 10 cm) was carried out to obtain scaffolds. The influence of the polymer concentration and the protein addition was observed by performing FTIR analyses and studied by analyzing the water contact angle and SEM images.

  6. Neural stem cell proliferation and differentiation in the conductive PEDOT-HA/Cs/Gel scaffold for neural tissue engineering.

    Science.gov (United States)

    Wang, Shuping; Guan, Shui; Xu, Jianqiang; Li, Wenfang; Ge, Dan; Sun, Changkai; Liu, Tianqing; Ma, Xuehu

    2017-09-26

    Engineering scaffolds with excellent electro-activity is increasingly important in tissue engineering and regenerative medicine. Herein, conductive poly(3,4-ethylenedioxythiophene) doped with hyaluronic acid (PEDOT-HA) nanoparticles were firstly synthesized via chemical oxidant polymerization. A three-dimensional (3D) PEDOT-HA/Cs/Gel scaffold was then developed by introducing PEDOT-HA nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. HA, as a bridge, not only was used as a dopant, but also combined PEDOT into the Cs/Gel via chemical crosslinking. The PEDOT-HA/Cs/Gel scaffold was used as a conductive substrate for neural stem cell (NSC) culture in vitro. The results demonstrated that the PEDOT-HA/Cs/Gel scaffold had excellent biocompatibility for NSC proliferation and differentiation. 3D confocal fluorescence images showed cells attached on the channel surface of Cs/Gel and PEDOT-HA/Cs/Gel scaffolds with a normal neuronal morphology. Compared to the Cs/Gel scaffold, the PEDOT-HA/Cs/Gel scaffold not only promoted NSC proliferation with up-regulated expression of Ki67, but also enhanced NSC differentiation into neurons and astrocytes with up-regulated expression of β tubulin-III and GFAP, respectively. It is expected that this electro-active and bio-active PEDOT-HA/Cs/Gel scaffold will be used as a conductive platform to regulate NSC behavior for neural tissue engineering.

  7. Increased Paracrine Immunomodulatory Potential of Mesenchymal Stromal Cells in Three-Dimensional Culture

    DEFF Research Database (Denmark)

    Follin, Bjarke; Juhl, Morten; Cohen, Smadar

    2016-01-01

    Mesenchymal stromal/stem cells (MSCs) have been investigated extensively through the past years, proving to have great clinical therapeutic potential. In vitro cultivation of MSCs in three-dimensional (3D) culture systems, such as scaffolds, hydrogels, or spheroids, have recently gained attention...... for tissue engineering applications. Studies on MSC spheroids demonstrated that such cultivation increased the paracrine immunomodulatory potential of the MSCs, accompanied by phenotypic alterations. In this review, we gather results from recent experimental studies on the immunomodulatory abilities of MSCs...... when cultured as spheroids or in biomaterials like scaffolds or hydrogels compared to regular two-dimensional (2D) culture and show that alterations occurring to MSCs in spheroids also occur in MSCs in biomaterials. We provide a brief description of known mechanisms of MSC immunomodulatory capacity...

  8. Delivery of Brain-Derived Neurotrophic Factor by 3D Biocompatible Polymeric Scaffolds for Neural Tissue Engineering and Neuronal Regeneration

    KAUST Repository

    Limongi, Tania; Rocchi, A.; Cesca, F.; Tan, H.; Miele, E.; Giugni, Andrea; Orlando, M.; Perrone Donnorso, M.; Perozziello, G.; Benfenati, Fabio; Di Fabrizio, Enzo M.

    2018-01-01

    Biopolymers are increasingly employed for neuroscience applications as scaffolds to drive and promote neural regrowth, thanks to their ability to mediate the upload and subsequent release of active molecules and drugs. Synthetic degradable polymers are characterized by different responses ranging from tunable distension or shrinkage to total dissolution, depending on the function they are designed for. In this paper we present a biocompatible microfabricated poly-ε-caprolactone (PCL) scaffold for primary neuron growth and maturation that has been optimized for the in vitro controlled release of brain-derived neurotrophic factor (BDNF). We demonstrate that the designed morphology confers to these devices an enhanced drug delivery capability with respect to monolithic unstructured supports. After incubation with BDNF, micropillared PCL devices progressively release the neurotrophin over 21 days in vitro. Moreover, the bioactivity of released BDNF is confirmed using primary neuronal cultures, where it mediates a consistent activation of BDNF signaling cascades, increased synaptic density, and neuronal survival. These results provide the proof-of-principle on the fabrication process of micropatterned PCL devices, which represent a promising therapeutic option to enhance neuronal regeneration after lesion and for neural tissue engineering and prosthetics.

  9. Delivery of Brain-Derived Neurotrophic Factor by 3D Biocompatible Polymeric Scaffolds for Neural Tissue Engineering and Neuronal Regeneration

    KAUST Repository

    Limongi, Tania

    2018-04-04

    Biopolymers are increasingly employed for neuroscience applications as scaffolds to drive and promote neural regrowth, thanks to their ability to mediate the upload and subsequent release of active molecules and drugs. Synthetic degradable polymers are characterized by different responses ranging from tunable distension or shrinkage to total dissolution, depending on the function they are designed for. In this paper we present a biocompatible microfabricated poly-ε-caprolactone (PCL) scaffold for primary neuron growth and maturation that has been optimized for the in vitro controlled release of brain-derived neurotrophic factor (BDNF). We demonstrate that the designed morphology confers to these devices an enhanced drug delivery capability with respect to monolithic unstructured supports. After incubation with BDNF, micropillared PCL devices progressively release the neurotrophin over 21 days in vitro. Moreover, the bioactivity of released BDNF is confirmed using primary neuronal cultures, where it mediates a consistent activation of BDNF signaling cascades, increased synaptic density, and neuronal survival. These results provide the proof-of-principle on the fabrication process of micropatterned PCL devices, which represent a promising therapeutic option to enhance neuronal regeneration after lesion and for neural tissue engineering and prosthetics.

  10. The effects of dynamic and three-dimensional environments on chondrogenic differentiation of bone marrow stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Youngmee; Kim, Sang-Heon; Kim, Soo Hyun [Biomaterials Research Center, Korea Institute of Science and Technology, PO Box 131, Cheonryang, Seoul, 130-650 (Korea, Republic of); Kim, Young Ha, E-mail: soohkim@kist.re.k [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2009-10-15

    Articular cartilage is subjected to complex loading, which plays a major role in its growth, development and maintenance. Previously, we found that mechanical stimuli enhanced the development and function of engineered cartilage tissues in elastic mechano-active poly(lactide-co-caprolactone) (PLCL) scaffolds. In addition, it is well known that the three-dimensional spatial organization of cells and extracellular matrices in hydrogels is crucial to chondrogenesis. This study was conducted to enhance the chondrogenic differentiation of bone marrow stromal cells (BMSCs) in the hybrid scaffolds of fibrin gels and PLCL scaffolds in dynamic environments by compression. A highly elastic scaffold was fabricated from very elastic PLCL with 85% porosity and a 300-500{mu}m pore size using a gel-pressing method. A mixture of rabbit BMSCs and fibrin gels was then seeded onto the PLCL scaffolds and subjected to continuous compressive deformation of 5% strain at 0.1 Hz for 10 days in a chondrogenic medium containing 10 ng ml{sup -1} TGF-beta{sub 1}. The BMSCs-seeded scaffold constructs were then implanted subcutaneously into nude mice. As a control, the cell-PLCL scaffold constructs were cultured under dynamic conditions or the cell-PLCL/fibrin hybrid scaffold constructs and the cell-PLCL scaffold constructs were cultured under static conditions for 10 days in vitro. The results revealed that cells adhered onto the hybrid scaffolds of fibrin gels and PLCL scaffolds cultured under dynamic conditions. In addition, the accumulation of the extracellular matrix of cell-scaffold constructs, which was increased through mechanical stimulation, showed that chondrogenic differentiation was sustained and enhanced significantly in the stimulated hybrid scaffold constructs. Overall, the results of this study indicate that the proper periodic application of dynamic compression and the three-dimensional environments of the hybrid scaffolds composed of fibrin gels and elastic PLCL can encourage

  11. Large 3D direct laser written scaffolds for tissue engineering applications

    Science.gov (United States)

    Trautmann, Anika; Rüth, Marieke; Lemke, Horst-Dieter; Walther, Thomas; Hellmann, Ralf

    2018-01-01

    We report on the fabrication of three-dimensional direct laser written scaffolds for tissue engineering and the seeding of primary fibroblasts on these structures. Scaffolds are realized by two-photon absorption induced polymerization in the inorganic-organic hybrid polymer OrmoComp using a 515 nm femtosecond laser. A nonstop single-line single-pass writing process is implemented in order to produce periodic reproducible large scaled structures with a dimension in the range of several millimeters and reduce process time to less than one hour. This method allows us to determine optimized process parameters for writing stable structures while achieving pore sizes ranging from 5 μm to 90 μm and a scanning speed of up to 5 mm/s. After a multi-stage post-treatment, normal human dermal fibroblasts are applied to the scaffolds to test if these macroscopic structures with large surface and numerous small gaps between the pores provide nontoxic conditions. Furthermore, we study the cell behavior in this environment and observe both cell growth on as well as ingrowth on the three-dimensional structures. In particular, fibroblasts adhere and grow also on the vertical walls of the scaffolds.

  12. Growing B Lymphocytes in a Three-Dimensional Culture System

    Science.gov (United States)

    Wu, J. H. David; Bottaro, Andrea

    2010-01-01

    A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing

  13. Cylindrical Three-Dimensional Porous Anodic Alumina Networks

    Directory of Open Access Journals (Sweden)

    Pedro M. Resende

    2016-11-01

    Full Text Available The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.

  14. Diffraction limited focusing with controllable arbitrary three-dimensional polarization

    International Nuclear Information System (INIS)

    Chen, Weibin; Zhan, Qiwen

    2010-01-01

    We propose a new approach that enables full control over the three-dimensional state of polarization and the field distribution near the focus of a high numerical aperture objective lens. By combining the electric dipole radiation and a vectorial diffraction method, the input field at the pupil plane for generating arbitrary three-dimensionally oriented linear polarization at the focal point with a diffraction limited spot size is found analytically by solving the inverse problem. Arbitrary three-dimensional elliptical polarization can be obtained by introducing a second electric dipole oriented in the orthogonal plane with appropriate amplitude and phase differences

  15. Fusion of three-dimensional X-ray angiography and three-dimensional echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Rasche, Volker [University of Ulm, Department of Internal Medicine II, Ulm (Germany); Philips Medical Systems, Bothell, WA (United States); Mansour, Moussa; Reddy, Vivek; Singh, Jagmeet P.; Ruskin, Jeremy [Massachusetts General Hospital, Harvard Medical School, Cardiac Arrhythmia Service, Boston, MA (United States); Qureshi, Answer [Massachusetts General Hospital, Harvard Medical School, Echocardiography, Boston, MA (United States); Manzke, Robert; Sokka, Sham [Philips Research North America, Clinical Sites Research, Briacliff Manor, NY (United States)

    2008-03-15

    Cardiovascular intervention guidance requires knowledge of heart function relative to its blood supply or venous drainage. Functional and vascular anatomic data are usually generated on different imaging systems, so fusion of the data is necessary to simultaneously visualize the results for intervention planning and guidance. The objective of this work is to establish the feasibility of fusing volumetric ultrasound (U/S) data with three-dimensional (3D) X-ray imaging data for visualization of cardiac morphology, function and coronary venous drainage. Temporally resolved U/S volume data was registered with the 3D reconstruction of vascular structures derived from X-ray modeling and reconstruction. U/S image registration was obtained by optical tracking fiducial markers with simultaneous X-ray imaging. The proposed technique was applied to phantom data for accuracy assessment of the registration process and to biventricular pacemaker implantation as clinical example. Fusion of U/S data with 3D X-ray reconstruction data produced an RMS registration error below 2 mm. Preliminary clinical feasibility of U/S-derived data synchronously with X-ray derived 3D coronary venography was established. This technique can be applied for fusion of functional U/S data with 3D anatomic X-ray data of the coronary veins during a biventricular pacemaker implantation procedures. (orig.)

  16. Three-dimensional modelling and three-dimensional printing in pediatric and congenital cardiac surgery.

    Science.gov (United States)

    Kiraly, Laszlo

    2018-04-01

    Three-dimensional (3D) modelling and printing methods greatly support advances in individualized medicine and surgery. In pediatric and congenital cardiac surgery, personalized imaging and 3D modelling presents with a range of advantages, e.g., better understanding of complex anatomy, interactivity and hands-on approach, possibility for preoperative surgical planning and virtual surgery, ability to assess expected results, and improved communication within the multidisciplinary team and with patients. 3D virtual and printed models often add important new anatomical findings and prompt alternative operative scenarios. For the lack of critical mass of evidence, controlled randomized trials, however, most of these general benefits remain anecdotal. For an individual surgical case-scenario, prior knowledge, preparedness and possibility of emulation are indispensable in raising patient-safety. It is advocated that added value of 3D printing in healthcare could be raised by establishment of a multidisciplinary centre of excellence (COE). Policymakers, research scientists, clinicians, as well as health care financers and local entrepreneurs should cooperate and communicate along a legal framework and established scientific guidelines for the clinical benefit of patients, and towards financial sustainability. It is expected that besides the proven utility of 3D printed patient-specific anatomical models, 3D printing will have a major role in pediatric and congenital cardiac surgery by providing individually customized implants and prostheses, especially in combination with evolving techniques of bioprinting.

  17. Fusion of three-dimensional X-ray angiography and three-dimensional echocardiography

    International Nuclear Information System (INIS)

    Rasche, Volker; Mansour, Moussa; Reddy, Vivek; Singh, Jagmeet P.; Ruskin, Jeremy; Qureshi, Answer; Manzke, Robert; Sokka, Sham

    2008-01-01

    Cardiovascular intervention guidance requires knowledge of heart function relative to its blood supply or venous drainage. Functional and vascular anatomic data are usually generated on different imaging systems, so fusion of the data is necessary to simultaneously visualize the results for intervention planning and guidance. The objective of this work is to establish the feasibility of fusing volumetric ultrasound (U/S) data with three-dimensional (3D) X-ray imaging data for visualization of cardiac morphology, function and coronary venous drainage. Temporally resolved U/S volume data was registered with the 3D reconstruction of vascular structures derived from X-ray modeling and reconstruction. U/S image registration was obtained by optical tracking fiducial markers with simultaneous X-ray imaging. The proposed technique was applied to phantom data for accuracy assessment of the registration process and to biventricular pacemaker implantation as clinical example. Fusion of U/S data with 3D X-ray reconstruction data produced an RMS registration error below 2 mm. Preliminary clinical feasibility of U/S-derived data synchronously with X-ray derived 3D coronary venography was established. This technique can be applied for fusion of functional U/S data with 3D anatomic X-ray data of the coronary veins during a biventricular pacemaker implantation procedures. (orig.)

  18. Fabrication of malleable three-dimensional-printed customized bolus using three-dimensional scanner.

    Directory of Open Access Journals (Sweden)

    Jae Won Park

    Full Text Available A three-dimensional (3D-printed customized bolus (3D bolus can be used for radiotherapy application to irregular surfaces. However, bolus fabrication based on computed tomography (CT scans is complicated and also delivers unwanted irradiation. Consequently, we fabricated a bolus using a 3D scanner and evaluated its efficacy. The head of an Alderson Rando phantom was scanned with a 3D scanner. The 3D surface data were exported and reconstructed with Geomagic Design X software. A 3D bolus of 5-mm thickness designed to fit onto the nose was printed with the use of rubber-like printing material, and a radiotherapy plan was developed. We successfully fabricated the customized 3D bolus, and further, a CT simulation indicated an acceptable fit of the 3D bolus to the nose. There was no air gap between the bolus and the phantom surface. The percent depth dose (PDD curve of the phantom with the 3D bolus showed an enhanced surface dose when compared with that of the phantom without the bolus. The PDD of the 3D bolus was comparable with that of a commercial superflab bolus. The radiotherapy plan considering the 3D bolus showed improved target coverage when compared with that without the bolus. Thus, we successfully fabricated a customized 3D bolus for an irregular surface using a 3D scanner instead of a CT scanner.

  19. Three-dimensional multichannel aerogel of carbon quantum dots for high-performance supercapacitors

    Science.gov (United States)

    Lv, Lingxiao; Fan, Yueqiong; Chen, Qing; Zhao, Yang; Hu, Yue; Zhang, Zhipan; Chen, Nan; Qu, Liangti

    2014-06-01

    A three-dimensional (3D) carbon quantum dot (CQD) aerogel has been prepared by in situ assembling CQDs in the sol-gel polymerization of resorcinol (R) and formaldehyde (F) and subsequently pyrolyzing the formed CQD gel. Compared to the supercapacitor based on the CQD-free aerogel, the supercapacitor fabricated with the CQD aerogel showed 20-fold higher specific capacitance (294.7 F g-1 at the current density of 0.5 A g-1) and an excellent stability over 1000 consecutive charge-discharge cycles.

  20. Programmable self-assembly of three-dimensional nanostructures from 10,000 unique components

    Science.gov (United States)

    Ong, Luvena L.; Hanikel, Nikita; Yaghi, Omar K.; Grun, Casey; Strauss, Maximilian T.; Bron, Patrick; Lai-Kee-Him, Josephine; Schueder, Florian; Wang, Bei; Wang, Pengfei; Kishi, Jocelyn Y.; Myhrvold, Cameron; Zhu, Allen; Jungmann, Ralf; Bellot, Gaetan; Ke, Yonggang; Yin, Peng

    2017-12-01

    Nucleic acids (DNA and RNA) are widely used to construct nanometre-scale structures with ever increasing complexity, with possible application in fields such as structural biology, biophysics, synthetic biology and photonics. The nanostructures are formed through one-pot self-assembly, with early kilodalton-scale examples containing typically tens of unique DNA strands. The introduction of DNA origami, which uses many staple strands to fold one long scaffold strand into a desired structure, has provided access to megadalton-scale nanostructures that contain hundreds of unique DNA strands. Even larger DNA origami structures are possible, but manufacturing and manipulating an increasingly long scaffold strand remains a challenge. An alternative and more readily scalable approach involves the assembly of DNA bricks, which each consist of four short binding domains arranged so that the bricks can interlock. This approach does not require a scaffold; instead, the short DNA brick strands self-assemble according to specific inter-brick interactions. First-generation bricks used to create three-dimensional structures are 32 nucleotides long, consisting of four eight-nucleotide binding domains. Protocols have been designed to direct the assembly of hundreds of distinct bricks into well formed structures, but attempts to create larger structures have encountered practical challenges and had limited success. Here we show that DNA bricks with longer, 13-nucleotide binding domains make it possible to self-assemble 0.1-1-gigadalton, three-dimensional nanostructures from tens of thousands of unique components, including a 0.5-gigadalton cuboid containing about 30,000 unique bricks and a 1-gigadalton rotationally symmetric tetramer. We also assembled a cuboid that contains around 10,000 bricks and about 20,000 uniquely addressable, 13-base-pair ‘voxels’ that serves as a molecular canvas for three-dimensional sculpting. Complex, user-prescribed, three-dimensional cavities can

  1. Progress of radiotherapy by three-dimensional treatment planning

    International Nuclear Information System (INIS)

    Imada, Hajime; Nomoto, Satoshi; Takahashi, Hiroyuki; Nakata, Hajime

    1998-01-01

    The recent progress of three-dimensional radiation treatment planning was reviewed. And clinical cases such as lung cancer and breast cancer are introduced. In the University of Occupational and Development Health, the treatment system FOCUS which is made up of CT simulator and linac was used mainly. Three-dimensional treatment planning was carried for about 90% of 330 patients who underwent radiotherapy for one year. The target becomes to be accurate and dose distribution with all CT slices in radiation field can be confirmed by using three-dimensional radiation treatment planning apparatus. High dose irradiation localized to tumor part is possible. Relations between total dose and volume of normal tissue and/or tumor can be estimated numerically and easily by DVH. A prediction of indication and affection became possible by this procedure. In conclusion, generalization of three-dimensional radiation treatment planning will bring progress of more effective radiotherapy with less adverse reaction. (K.H.). 21 refs

  2. Feynman diagrams coupled to three-dimensional quantum gravity

    International Nuclear Information System (INIS)

    Barrett, John W

    2006-01-01

    A framework for quantum field theory coupled to three-dimensional quantum gravity is proposed. The coupling with quantum gravity regulates the Feynman diagrams. One recovers the usual Feynman amplitudes in the limit as the cosmological constant tends to zero

  3. Three-dimensional reconstruction and visualization system for medical images

    International Nuclear Information System (INIS)

    Preston, D.F.; Batnitzky, S.; Kyo Rak Lee; Cook, P.N.; Cook, L.T.; Dwyer, S.J.

    1982-01-01

    A three-dimensional reconstruction and visualization system could be of significant advantage in medical application such as neurosurgery and radiation treatment planning. The reconstructed anatomic structures from CT head scans could be used in a head stereotactic system to help plan the surgical procedure and the radiation treatment for a brain lesion. Also, the use of three-dimensional reconstruction algorithm provides for quantitative measures such as volume and surface area estimation of the anatomic features. This aspect of the three-dimensional reconstruction system may be used to monitor the progress or staging of a disease and the effects of patient treatment. Two cases are presented to illustrate the three-dimensional surface reconstruction and visualization system

  4. Three dimensional CT imaging of ossicular chain: a preliminary study

    International Nuclear Information System (INIS)

    Hu Chunhong; Zhong Shenbin; Fu Yindi; Zhu Wei; Wang Xueyuan; Chen Jianhua; Ding Yi

    2001-01-01

    Objective: To analysis the features of normal and abnormal ossicular chain in three dimensional images and asses the best parameters and its usefulness in diagnosis and treatment of chronic otitis media (COM). Methods: All patients, including 43 patients with normal ears and 24 ears with COM, were examined using spiral CT with inner ear software, 1-mm slice width and 1 pitch. SSD method was used in three dimensional reconstruction and the threshold was 100-300 Hu. Results: In normal cases, Malleus, incus, stapes crura, incudomalleal joints and incudostapedial joints were displayed well, but stapes footplate unsatisfactorily. The disruption of the ossicular chain showed in three-dimensional images in cases of chronic otitis media was in accord with that seen in the operation. Conclusion: It is very important for imaging with high quality through selecting proper parameters, and three-dimensional image can provide valuable information for surgery

  5. Analysis and validation of carbohydrate three-dimensional structures

    International Nuclear Information System (INIS)

    Lütteke, Thomas

    2009-01-01

    The article summarizes the information that is gained from and the errors that are found in carbohydrate structures in the Protein Data Bank. Validation tools that can locate these errors are described. Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein–carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein–carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures

  6. Utility of three-dimensional method for diagnosing meniscal lesions

    International Nuclear Information System (INIS)

    Ohshima, Suguru; Nomura, Kazutoshi; Hirano, Mako; Hashimoto, Noburo; Fukumoto, Tetsuya; Katahira, Kazuhiro

    1998-01-01

    MRI of the knee is a useful method for diagnosing meniscal tears. Although the spin echo method is usually used for diagnosing meniscal tears, we examined the utility of thin slice scan with the three-dimensional method. We reviewed 70 menisci in which arthroscopic findings were confirmed. In this series, sensitivity was 90.9% for medial meniscal injuries and 68.8% for lateral meniscal injuries. There were 3 meniscal tears in which we could not detect tears on preoperative MRI. We could find tears in two of these cases when re-evaluated using the same MRI. In conclusion, we can get the same diagnostic rate with the three-dimensional method compared with the spin echo method. Scan time of the three-dimensional method is 3 minutes, on the other hand that of spin echo method in 17 minutes. This slice scan with three-dimensional method is useful for screening meniscal injuries before arthroscopy. (author)

  7. Three-dimensional Simulation of Backward Raman Amplification

    International Nuclear Information System (INIS)

    Balakin, A.A.; Fraiman, G.M.; Fisch, N.J.

    2005-01-01

    Three-dimensional (3-D) simulations for the Backward Raman Amplification (BRA) are presented. The images illustrate the effects of pump depletion, pulse diffraction, non-homogeneous plasma density, and plasma ionization

  8. Magnetic structure of two- and three-dimensional supramolecular compounds

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S.; Schmalle, H.W.; Pellaux, R. [Zurich Univ. (Switzerland); Fischer, P.; Fauth, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ouladdiaf, B. [Institut Max von Laue - Paul Langevin, 75 - Paris (France)

    1997-09-01

    Supramolecular chiral networks of oxalato-bridged transition metals show either two- or three-dimensional structural features. The magnetic structures of such compounds have been investigated by means of elastic neutron powder diffraction. (author) 2 figs., 2 refs.

  9. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels; Sougrat, Rachid; Northan, Brian M.; Pennycook, Stephen J.

    2010-01-01

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM

  10. [Bone drilling simulation by three-dimensional imaging].

    Science.gov (United States)

    Suto, Y; Furuhata, K; Kojima, T; Kurokawa, T; Kobayashi, M

    1989-06-01

    The three-dimensional display technique has a wide range of medical applications. Pre-operative planning is one typical application: in orthopedic surgery, three-dimensional image processing has been used very successfully. We have employed this technique in pre-operative planning for orthopedic surgery, and have developed a simulation system for bone-drilling. Positive results were obtained by pre-operative rehearsal; when a region of interest is indicated by means of a mouse on the three-dimensional image displayed on the CRT, the corresponding region appears on the slice image which is displayed simultaneously. Consequently, the status of the bone-drilling is constantly monitored. In developing this system, we have placed emphasis on the quality of the reconstructed three-dimensional images, on fast processing, and on the easy operation of the surgical planning simulation.

  11. Standalone visualization tool for three-dimensional DRAGON geometrical models

    International Nuclear Information System (INIS)

    Lukomski, A.; McIntee, B.; Moule, D.; Nichita, E.

    2008-01-01

    DRAGON is a neutron transport and depletion code able to solve one-, two- and three-dimensional problems. To date DRAGON provides two visualization modules, able to represent respectively two- and three-dimensional geometries. The two-dimensional visualization module generates a postscript file, while the three dimensional visualization module generates a MATLAB M-file with instructions for drawing the tracks in the DRAGON TRACKING data structure, which implicitly provide a representation of the geometry. The current work introduces a new, standalone, tool based on the open-source Visualization Toolkit (VTK) software package which allows the visualization of three-dimensional geometrical models by reading the DRAGON GEOMETRY data structure and generating an axonometric image which can be manipulated interactively by the user. (author)

  12. Study of three-dimensional image display by systemic CT

    International Nuclear Information System (INIS)

    Fujioka, Tadao; Ebihara, Yoshiyuki; Unei, Hiroshi; Hayashi, Masao; Shinohe, Tooru; Wada, Yuji; Sakai, Takatsugu; Kashima, Kenji; Fujita, Yoshihiro

    1989-01-01

    A head phantom for CT was scanned at 2 mm intervals from the cervix to the vertex in an attempt to obtain a three-dimensional image display of bones and facial epidermis from an ordinary axial image. Clinically, three-dimensional images were formed at eye sockets and hip joints. With the three-dimensional image using the head phantom, the entire head could be displayed at any angle. Clinically, images were obtained that could not be attained by ordinary CT scanning, such as broken bones in eye sockets and stereoscopic structure at the bottom of a cranium. The three-dimensional image display is considered to be useful in clinical diagnosis. (author)

  13. Three-Dimensional Structure Determination of Botulinum Toxin

    National Research Council Canada - National Science Library

    Stevens, Ray

    1997-01-01

    ...) Based on the structure of the neurotoxin, understand the toxins mechanism of action. We have accomplished the first goal of determining the three-dimensional structure of the 150 kD botulinum neurotoxin serotype...

  14. Three-Dimensional Structure Determination of Botulinum Toxin

    National Research Council Canada - National Science Library

    Stevens, Ray

    1998-01-01

    ...) Based on the structure of the neurotoxin, understand the toxins mechanism of action. We have accomplished the first goal of determining the three-dimensional structure of the 150 kD botulinum neurotoxin serotype...

  15. Direct Linear Transformation Method for Three-Dimensional Cinematography

    Science.gov (United States)

    Shapiro, Robert

    1978-01-01

    The ability of Direct Linear Transformation Method for three-dimensional cinematography to locate points in space was shown to meet the accuracy requirements associated with research on human movement. (JD)

  16. A simple remark on three dimensional gauge theories

    International Nuclear Information System (INIS)

    Lemes, V.E.R.; Linhares de Jesus, C.; Sasaki, C.A.G.; Sorella, S.P.; Vilar, L.C.Q.; Ventura, O.S.

    1997-08-01

    Classical three dimensional Yang-Mills is seen to be related to the topological Chern-Simons term through a nonlinear but fully local and covariant gauge field redefinition. A classical recursive cohomological argument is proved. (author)

  17. Computational study of three-dimensional wake structure

    International Nuclear Information System (INIS)

    Himeno, R.; Shirayama, S.; Kamo, K.; Kuwahara, K.

    1986-01-01

    Three-dimensional wake structure is studied by numerically solving the incompressible Navier-Stokes equations. Results are visualized by a three-dimensional color graphic system. It was found that a pair of vortex tubes separated from a body plays the most important role in the wake. Near the body vortex tubes are rather stable, however, they gradually become unsteady as they flow down

  18. Three-dimensional magnetophotonic crystals based on artificial opals

    Science.gov (United States)

    Baryshev, A. V.; Kodama, T.; Nishimura, K.; Uchida, H.; Inoue, M.

    2004-06-01

    We fabricated and experimentally investigated three-dimensional magnetophotonic crystals (3D MPCs) based on artificial opals. Opal samples with three-dimensional dielectric lattices were impregnated with different types of magnetic material. Magnetic and structural properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. We have shown that magnetic materials synthesized in voids of opal lattices and the composites obtained have typical magnetic properties.

  19. Three-dimensional magnetophotonic crystals based on artificial opals

    International Nuclear Information System (INIS)

    Baryshev, A.V.; Kodama, T.; Nishimura, K.; Uchida, H.; Inoue, M.

    2004-01-01

    We fabricated and experimentally investigated three-dimensional magnetophotonic crystals (3D MPCs) based on artificial opals. Opal samples with three-dimensional dielectric lattices were impregnated with different types of magnetic material. Magnetic and structural properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. We have shown that magnetic materials synthesized in voids of opal lattices and the composites obtained have typical magnetic properties

  20. Three-dimensional transesophageal echocardiography of the atrial septal defects

    Directory of Open Access Journals (Sweden)

    Romero-Cárdenas Ángel

    2008-07-01

    Full Text Available Abstract Transesophageal echocardiography has advantages over transthoracic technique in defining morphology of atrial structures. Even though real time three-dimensional echocardiographic imaging is a reality, the off-line reconstruction technique usually allows to obtain higher spatial resolution images. The purpose of this study was to explore the accuracy of off-line three-dimensional transesophageal echocardiography in a spectrum of atrial septal defects by comparing them with representative anatomic specimens.

  1. Comparison of two three-dimensional cephalometric analysis computer software

    OpenAIRE

    Sawchuk, Dena; Alhadlaq, Adel; Alkhadra, Thamer; Carlyle, Terry D; Kusnoto, Budi; El-Bialy, Tarek

    2014-01-01

    Background: Three-dimensional cephalometric analyses are getting more attraction in orthodontics. The aim of this study was to compare two softwares to evaluate three-dimensional cephalometric analyses of orthodontic treatment outcomes. Materials and Methods: Twenty cone beam computed tomography images were obtained using i-CAT® imaging system from patient's records as part of their regular orthodontic records. The images were analyzed using InVivoDental5.0 (Anatomage Inc.) and 3DCeph™ (Unive...

  2. Simulation on three dimensional bubble formation using MARS

    International Nuclear Information System (INIS)

    Kunugi, Tomoaki

    1997-01-01

    This paper describes a numerical simulation on three-dimensional bubble formation by means of the MARS (Multi-interfaces Advection and Reconstruction Solver) developed by the author. The comparison between two-dimensional and three-dimensional simulation on an agglomeration of two bubbles is discussed. Moreover, some simulation results regarding a phase change phenomena such as a boiling and condensation in a two dimensional enclosure with heated and cooled walls are presented. (author)

  3. Three-dimensional reconstruction of functional brain images

    International Nuclear Information System (INIS)

    Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao

    1999-01-01

    We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

  4. Three-dimensional stellarator equilibrium as an ohmic steady state

    International Nuclear Information System (INIS)

    Park, W.; Monticello, D.A.; Strauss, H.; Manickam, J.

    1985-07-01

    A stable three-dimensional stellarator equilibrium can be obtained numerically by a time-dependent relaxation method using small values of dissipation. The final state is an ohmic steady state which approaches an ohmic equilibrium in the limit of small dissipation coefficients. We describe a method to speed up the relaxation process and a method to implement the B vector . del p = 0 condition. These methods are applied to obtain three-dimensional heliac equilibria using the reduced heliac equations

  5. Discretization model for nonlinear dynamic analysis of three dimensional structures

    International Nuclear Information System (INIS)

    Hayashi, Y.

    1982-12-01

    A discretization model for nonlinear dynamic analysis of three dimensional structures is presented. The discretization is achieved through a three dimensional spring-mass system and the dynamic response obtained by direct integration of the equations of motion using central diferences. First the viability of the model is verified through the analysis of homogeneous linear structures and then its performance in the analysis of structures subjected to impulsive or impact loads, taking into account both geometrical and physical nonlinearities is evaluated. (Author) [pt

  6. Three-dimensional reconstruction of functional brain images

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao [Kyoto Univ. (Japan)

    1999-08-01

    We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

  7. Advancing three-dimensional MEMS by complimentary laser micro manufacturing

    Science.gov (United States)

    Palmer, Jeremy A.; Williams, John D.; Lemp, Tom; Lehecka, Tom M.; Medina, Francisco; Wicker, Ryan B.

    2006-01-01

    This paper describes improvements that enable engineers to create three-dimensional MEMS in a variety of materials. It also provides a means for selectively adding three-dimensional, high aspect ratio features to pre-existing PMMA micro molds for subsequent LIGA processing. This complimentary method involves in situ construction of three-dimensional micro molds in a stand-alone configuration or directly adjacent to features formed by x-ray lithography. Three-dimensional micro molds are created by micro stereolithography (MSL), an additive rapid prototyping technology. Alternatively, three-dimensional features may be added by direct femtosecond laser micro machining. Parameters for optimal femtosecond laser micro machining of PMMA at 800 nanometers are presented. The technical discussion also includes strategies for enhancements in the context of material selection and post-process surface finish. This approach may lead to practical, cost-effective 3-D MEMS with the surface finish and throughput advantages of x-ray lithography. Accurate three-dimensional metal microstructures are demonstrated. Challenges remain in process planning for micro stereolithography and development of buried features following femtosecond laser micro machining.

  8. Rapid Three-Dimensional Printing in Water Using Semiconductor-Metal Hybrid Nanoparticles as Photoinitiators.

    Science.gov (United States)

    Pawar, Amol Ashok; Halivni, Shira; Waiskopf, Nir; Ben-Shahar, Yuval; Soreni-Harari, Michal; Bergbreiter, Sarah; Banin, Uri; Magdassi, Shlomo

    2017-07-12

    Additive manufacturing processes enable fabrication of complex and functional three-dimensional (3D) objects ranging from engine parts to artificial organs. Photopolymerization, which is the most versatile technology enabling such processes through 3D printing, utilizes photoinitiators that break into radicals upon light absorption. We report on a new family of photoinitiators for 3D printing based on hybrid semiconductor-metal nanoparticles. Unlike conventional photoinitiators that are consumed upon irradiation, these particles form radicals through a photocatalytic process. Light absorption by the semiconductor nanorod is followed by charge separation and electron transfer to the metal tip, enabling redox reactions to form radicals in aerobic conditions. In particular, we demonstrate their use in 3D printing in water, where they simultaneously form hydroxyl radicals for the polymerization and consume dissolved oxygen that is a known inhibitor. We also demonstrate their potential for two-photon polymerization due to their giant two-photon absorption cross section.

  9. Visual Interpretation with Three-Dimensional Annotations (VITA): Three-Dimensional Image Interpretation Tool for Radiological Reporting

    OpenAIRE

    Roy, Sharmili; Brown, Michael S.; Shih, George L.

    2013-01-01

    This paper introduces a software framework called Visual Interpretation with Three-Dimensional Annotations (VITA) that is able to automatically generate three-dimensional (3D) visual summaries based on radiological annotations made during routine exam reporting. VITA summaries are in the form of rotating 3D volumes where radiological annotations are highlighted to place important clinical observations into a 3D context. The rendered volume is produced as a Digital Imaging and Communications i...

  10. Electron tomography, three-dimensional Fourier analysis and colour prediction of a three-dimensional amorphous biophotonic nanostructure

    Science.gov (United States)

    Shawkey, Matthew D.; Saranathan, Vinodkumar; Pálsdóttir, Hildur; Crum, John; Ellisman, Mark H.; Auer, Manfred; Prum, Richard O.

    2009-01-01

    Organismal colour can be created by selective absorption of light by pigments or light scattering by photonic nanostructures. Photonic nanostructures may vary in refractive index over one, two or three dimensions and may be periodic over large spatial scales or amorphous with short-range order. Theoretical optical analysis of three-dimensional amorphous nanostructures has been challenging because these structures are difficult to describe accurately from conventional two-dimensional electron microscopy alone. Intermediate voltage electron microscopy (IVEM) with tomographic reconstruction adds three-dimensional data by using a high-power electron beam to penetrate and image sections of material sufficiently thick to contain a significant portion of the structure. Here, we use IVEM tomography to characterize a non-iridescent, three-dimensional biophotonic nanostructure: the spongy medullary layer from eastern bluebird Sialia sialis feather barbs. Tomography and three-dimensional Fourier analysis reveal that it is an amorphous, interconnected bicontinuous matrix that is appropriately ordered at local spatial scales in all three dimensions to coherently scatter light. The predicted reflectance spectra from the three-dimensional Fourier analysis are more precise than those predicted by previous two-dimensional Fourier analysis of transmission electron microscopy sections. These results highlight the usefulness, and obstacles, of tomography in the description and analysis of three-dimensional photonic structures. PMID:19158016

  11. Three dimensional gel dosimetry by use of nuclear magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    De Deene, Y.; De Wagter, C.; Van Duyse, B.; Achten, E.; De Neve, W.; De Poorter, J.

    1995-01-01

    As co-monomers are found to polymerize by radiation, they are eligible for constructing a three dimensional dosimeter. Another kind of three dimensional dosimeter, based on the radiation sensitivity of the ferrous ions in a Fricke solution, was tested in a previous study. However, a major problem that occurs in this kind of gel dosimeters is the diffusion of the ferric and ferrous ions. The co-monomer gels are more stable. The degree of polymerisation is visualized with a clinical MRI system. Acrylamide and N,N-methylene-bis-acrylamide are dissolved in a gel composed of gelatin and water. By irradiation the co-monomers are polymerized to polyacrylamide. The gel is casted in humanoid forms. As such, a simulation of the irradiation of the patient can be performed. Magnetic resonance relaxivity images of the irradiated gel display the irradiation dose. The images of the gel are fused with the radiological images of the patient. Quantitation of the dose response of the co-monomer gel is obtained through calibration by test tubes

  12. Three dimensional gel dosimetry by use of nuclear magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    De Deene, Y; De Wagter, C; Van Duyse, B; Achten, E; De Neve, W [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; De Poorter, J [Ghent Univ. (Belgium). Dept. of Magnetic Resonance

    1995-12-01

    As co-monomers are found to polymerize by radiation, they are eligible for constructing a three dimensional dosimeter. Another kind of three dimensional dosimeter, based on the radiation sensitivity of the ferrous ions in a Fricke solution, was tested in a previous study. However, a major problem that occurs in this kind of gel dosimeters is the diffusion of the ferric and ferrous ions. The co-monomer gels are more stable. The degree of polymerisation is visualized with a clinical MRI system. Acrylamide and N,N-methylene-bis-acrylamide are dissolved in a gel composed of gelatin and water. By irradiation the co-monomers are polymerized to polyacrylamide. The gel is casted in humanoid forms. As such, a simulation of the irradiation of the patient can be performed. Magnetic resonance relaxivity images of the irradiated gel display the irradiation dose. The images of the gel are fused with the radiological images of the patient. Quantitation of the dose response of the co-monomer gel is obtained through calibration by test tubes.

  13. Three-dimensional graphene/polyaniline composite material for high-performance supercapacitor applications

    International Nuclear Information System (INIS)

    Liu, Huili; Wang, Yi; Gou, Xinglong; Qi, Tao; Yang, Jun; Ding, Yulong

    2013-01-01

    Highlights: ► A novel 3D graphene showed high specific surface area and large mesopore volume. ► Aniline monomer was polymerized in the presence of 3D graphene at room temperature. ► The supercapacitive properties were studied by CV and charge–discharge tests. ► The composite show a high gravimetric capacitance and good cyclic stability. ► The 3D graphene/polyaniline has never been report before our work. -- Abstract: A novel three-dimensional (3D) graphene/polyaniline nanocomposite material which is synthesized using in situ polymerization of aniline monomer on the graphene surface is reported as an electrode for supercapacitors. The morphology and structure of the material are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The electrochemical properties of the resulting materials are systematically studied using cyclic voltammetry (CV) and constant current charge–discharge tests. A high gravimetric capacitance of 463 F g −1 at a scan rate of 1 mV s −1 is obtained by means of CVs with 3 mol L −1 KOH as the electrolyte. In addition, the composite material shows only 9.4% capacity loss after 500 cycles, indicating better cyclic stability for supercapacitor applications. The high specific surface area, large mesopore volume and three-dimensional nanoporous structure of 3D graphene could contribute to the high specific capacitance and good cyclic life

  14. Parallel geometric classification of stem cells by their three-dimensional morphology

    International Nuclear Information System (INIS)

    Juba, Derek; Cardone, Antonio; Yiu Ip, Cheuk; Varshney, Amitabh; Simon Jr, Carl G; K Tison, Christopher; Kumar, Girish; Brady, Mary

    2013-01-01

    There is a need for tools to classify cells based on their three-dimensional (3D) shape. Cells exist in vivo in 3D, cells are frequently cultured within 3D scaffolds in vitro and 3D scaffolds are used for cell delivery in tissue engineering therapies. Recent work indicates that the physical structure of a tissue engineering scaffold can direct stem cell function by driving stem cells into morphologies that induce their differentiation. Thus, we have developed a rapid method for classifying cells based on their 3D shape. First, random lines are intersected with 3D Z-stacks of confocal images of stem cells. The intersection lengths are stored in histograms, which are then used to train a support vector machine (SVM) learning algorithm to distinguish between stem cells cultured on differentiation-inducing 3D scaffolds and those cultured on non-differentiating flat substrates. The trained SVM is able to properly classify the ‘new’ query cells over 80% of the time. The algorithm is easily parallelizable and we demonstrate its implementation on a commodity graphics processing unit (GPU). Use of a GPU to run the algorithm increases throughput by over 100-fold as compared to use of a CPU. The algorithm is also progressive, providing an approximate answer quickly and refining the answer over time. This allows further increase in the throughput of the algorithm by allowing the SVM classification scheme to terminate early if it becomes confident enough of the class of the cell being analyzed. These results demonstrate a rapid method for classifying stem cells based on their 3D shape that can be used by tissue engineers for identifying 3D tissue scaffold structures that drive stem cells into shapes that correlate with differentiation. (paper)

  15. Three dimensional extrusion printing induces polymer molecule alignment and cell organization within engineered cartilage.

    Science.gov (United States)

    Guo, Ting; Ringel, Julia P; Lim, Casey G; Bracaglia, Laura G; Noshin, Maeesha; Baker, Hannah B; Powell, Douglas A; Fisher, John P

    2018-04-16

    Proper cell-material interactions are critical to remain cell function and thus successful tissue regeneration. Many fabrication processes have been developed to create microenvironments to control cell attachment and organization on a three-dimensional (3D) scaffold. However, these approaches often involve heavy engineering and only the surface layer can be patterned. We found that 3D extrusion based printing at high temperature and pressure will result an aligned effect on the polymer molecules, and this molecular arrangement will further induce the cell alignment and different differentiation capacities. In particular, articular cartilage tissue is known to have zonal collagen fiber and cell orientation to support different functions, where collagen fibers and chondrocytes align parallel, randomly, and perpendicular, respectively, to the surface of the joint. Therefore, cell alignment was evaluated in a cartilage model in this study. We used small angle X-ray scattering analysis to substantiate the polymer molecule alignment phenomenon. The cellular response was evaluated both in vitro and in vivo. Seeded mesenchymal stem cells (MSCs) showed different morphology and orientation on scaffolds, as a combined result of polymer molecule alignment and printed scaffold patterns. Gene expression results showed improved superficial zonal chondrogenic marker expression in parallel-aligned group. The cell alignment was successfully maintained in the animal model after 7 days with distinct MSC morphology between the casted and parallel printed scaffolds. This 3D printing induced polymer and cell alignment will have a significant impact on developing scaffold with controlled cell-material interactions for complex tissue engineering while avoiding complicated surface treatment, and therefore provides new concept for effective tissue repairing in future clinical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

  16. Fabrication of three-dimensional porous cell-laden hydrogel for tissue engineering

    International Nuclear Information System (INIS)

    Hwang, Chang Mo; Sant, Shilpa; Masaeli, Mahdokht; Kachouie, Nezamoddin N; Zamanian, Behnam; Khademhosseini, Ali; Lee, Sang-Hoon

    2010-01-01

    For tissue engineering applications, scaffolds should be porous to enable rapid nutrient and oxygen transfer while providing a three-dimensional (3D) microenvironment for the encapsulated cells. This dual characteristic can be achieved by fabrication of porous hydrogels that contain encapsulated cells. In this work, we developed a simple method that allows cell encapsulation and pore generation inside alginate hydrogels simultaneously. Gelatin beads of 150-300 μm diameter were used as a sacrificial porogen for generating pores within cell-laden hydrogels. Gelation of gelatin at low temperature (4 0 C) was used to form beads without chemical crosslinking and their subsequent dissolution after cell encapsulation led to generation of pores within cell-laden hydrogels. The pore size and porosity of the scaffolds were controlled by the gelatin bead size and their volume ratio, respectively. Fabricated hydrogels were characterized for their internal microarchitecture, mechanical properties and permeability. Hydrogels exhibited a high degree of porosity with increasing gelatin bead content in contrast to nonporous alginate hydrogel. Furthermore, permeability increased by two to three orders while compressive modulus decreased with increasing porosity of the scaffolds. Application of these scaffolds for tissue engineering was tested by encapsulation of hepatocarcinoma cell line (HepG2). All the scaffolds showed similar cell viability; however, cell proliferation was enhanced under porous conditions. Furthermore, porous alginate hydrogels resulted in formation of larger spheroids and higher albumin secretion compared to nonporous conditions. These data suggest that porous alginate hydrogels may have provided a better environment for cell proliferation and albumin production. This may be due to the enhanced mass transfer of nutrients, oxygen and waste removal, which is potentially beneficial for tissue engineering and regenerative medicine applications.

  17. A plastic surgery application in evolution: three-dimensional printing.

    Science.gov (United States)

    Gerstle, Theodore L; Ibrahim, Ahmed M S; Kim, Peter S; Lee, Bernard T; Lin, Samuel J

    2014-02-01

    Three-dimensional printing represents an evolving technology still in its infancy. Currently, individuals and small business entities have the ability to manufacture physical objects from digital renderings, computer-aided design, and open source files. Design modifications and improvements in extrusion methods have made this technology much more affordable. This article explores the potential uses of three-dimensional printing in plastic surgery. A review was performed detailing the known uses of three-dimensional printing in medicine. The potential applications of three-dimensional printing in plastic surgery are discussed. Various applications for three-dimensional printing technology have emerged in medicine, including printing organs, printing body parts, bio-printing, and computer-aided tissue engineering. In plastic surgery, these tools offer various prospective applications for surgical planning, resident education, and the development of custom prosthetics. Numerous applications exist in medicine, including the printing of devices, implants, tissue replacements, and even whole organs. Plastic surgeons may likely find this technology indispensable in surgical planning, education, and prosthetic device design and development in the near future.

  18. Three-dimensional printing and pediatric liver disease.

    Science.gov (United States)

    Alkhouri, Naim; Zein, Nizar N

    2016-10-01

    Enthusiastic physicians and medical researchers are investigating the role of three-dimensional printing in medicine. The purpose of the current review is to provide a concise summary of the role of three-dimensional printing technology as it relates to the field of pediatric hepatology and liver transplantation. Our group and others have recently demonstrated the feasibility of printing three-dimensional livers with identical anatomical and geometrical landmarks to the native liver to facilitate presurgical planning of complex liver surgeries. Medical educators are exploring the use of three-dimensional printed organs in anatomy classes and surgical residencies. Moreover, mini-livers are being developed by regenerative medicine scientist as a way to test new drugs and, eventually, whole livers will be grown in the laboratory to replace organs with end-stage disease solving the organ shortage problem. From presurgical planning to medical education to ultimately the bioprinting of whole organs for transplantation, three-dimensional printing will change medicine as we know in the next few years.

  19. Three-dimensional magnetospheric equilibrium with isotropic pressure

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    1995-05-01

    In the absence of the toroidal flux, two coupled quasi two-dimensional elliptic equilibrium equations have been derived to describe self-consistent three-dimensional static magnetospheric equilibria with isotropic pressure in an optimal (Ψ,α,χ) flux coordinate system, where Ψ is the magnetic flux function, χ is a generalized poloidal angle, α is the toroidal angle, α = φ - δ(Ψ,φ,χ) is the toroidal angle, δ(Ψ,φ,χ) is periodic in φ, and the magnetic field is represented as rvec B = ∇Ψ x ∇α. A three-dimensional magnetospheric equilibrium code, the MAG-3D code, has been developed by employing an iterative metric method. The main difference between the three-dimensional and the two-dimensional axisymmetric solutions is that the field-aligned current and the toroidal magnetic field are finite for the three-dimensional case, but vanish for the two-dimensional axisymmetric case. With the same boundary flux surface shape, the two-dimensional axisymmetric results are similar to the three-dimensional magnetosphere at each local time cross section

  20. Three-dimensional imagery by encoding sources of X rays

    International Nuclear Information System (INIS)

    Magnin, Isabelle

    1987-01-01

    This research thesis addresses the theoretical and practical study of X ray coded sources, and thus notably aims at exploring whether it would be possible to transform a standard digital radiography apparatus (as those operated in radiology hospital departments) into a low cost three-dimensional imagery system. The author first recalls the principle of conventional tomography and improvement attempts, and describes imagery techniques based on the use of encoding openings and source encoding. She reports the modelling of an imagery system based on encoded sources of X ray, and addresses the original notion of three-dimensional response for such a system. The author then addresses the reconstruction method by considering the reconstruction of a plane object, of a multi-plane object, and of real three-dimensional object. The frequency properties and the tomographic capacities of various types of source codes are analysed. She describes a prototype tomography apparatus, and presents and discusses three-dimensional actual phantom reconstructions. She finally introduces a new principle of dynamic three-dimensional radiography which implements an acquisition technique by 'gating code'. The acquisition principle should allow the reconstruction of volumes animated by periodic deformations, such as the heart for example [fr

  1. Alginate foam-based three-dimensional culture to investigate drug sensitivity in primary leukaemia cells.

    Science.gov (United States)

    Karimpoor, Mahroo; Yebra-Fernandez, Eva; Parhizkar, Maryam; Orlu, Mine; Craig, Duncan; Khorashad, Jamshid S; Edirisinghe, Mohan

    2018-04-01

    The development of assays for evaluating the sensitivity of leukaemia cells to anti-cancer agents is becoming an important aspect of personalized medicine. Conventional cell cultures lack the three-dimensional (3D) structure of the bone marrow (BM), the extracellular matrix and stromal components which are crucial for the growth and survival of leukaemia stem cells. To accurately predict the sensitivity of the leukaemia cells in an in vitro assay a culturing system containing the essential components of BM is required. In this study, we developed a porous calcium alginate foam-based scaffold to be used for 3D culture. The new 3D culture was shown to be cell compatible as it supported the proliferation of both normal haematopoietic and leukaemia cells. Our cell differential assay for myeloid markers showed that the porous foam-based 3D culture enhanced myeloid differentiation in both leukaemia and normal haematopoietic cells compared to two-dimensional culture. The foam-based scaffold reduced the sensitivity of the leukaemia cells to the tested antileukaemia agents in K562 and HL60 leukaemia cell line model and also primary myeloid leukaemia cells. This observation supports the application of calcium alginate foams as scaffold components of the 3D cultures for investigation of sensitivity to antileukaemia agents in primary myeloid cells. © 2018 The Author(s).

  2. Single-cell printing to form three-dimensional lines of olfactory ensheathing cells

    International Nuclear Information System (INIS)

    Othon, Christina M; Ringeisen, Bradley R; Wu Xingjia; Anders, Juanita J

    2008-01-01

    Biological laser printing (BioLP(TM)) is a unique tool capable of printing high resolution two- and three-dimensional patterns of living mammalian cells, with greater than 95% viability. These results have been extended to primary cultured olfactory ensheathing cells (OECs), harvested from adult Sprague-Dawley rats. OECs have been found to provide stimulating environments for neurite outgrowth in spinal cord injury models. BioLP is unique in that small load volumes (∼μLs) are required to achieve printing, enabling low numbers of OECs to be harvested, concentrated and printed. BioLP was used to form several 8 mm lines of OECs throughout a multilayer hydrogel scaffold. The line width was as low as 20 μm, with most lines comprising aligned single cells. Fluorescent confocal microscopy was used to determine the functionality of the printed OECs, to monitor interactions between printed OECs, and to determine the extent of cell migration throughout the 3D scaffold. High-resolution printing of low cell count, harvested OECs is an important advancement for in vitro study of cell interactions and functionality. In addition, these cell-printed scaffolds may provide an alternative for spinal cord repair studies, as the single-cell patterns formed here are on relevant size scales for neurite outgrowth

  3. Three-dimensional particle image velocimetry measurement technique

    International Nuclear Information System (INIS)

    Hassan, Y.A.; Seeley, C.H.; Henderson, J.A.; Schmidl, W.D.

    2004-01-01

    The experimental flow visualization tool, Particle Image Velocimetry (PIV), is being used to determine the velocity field in two-dimensional fluid flows. In the past few years, the technique has been improved to allow the capture of flow fields in three dimensions. This paper describes changes which were made to two existing two-dimensional tracking algorithms to enable them to track three-dimensional PIV data. Results of the tests performed on these three-dimensional routines with synthetic data are presented. Experimental data was also used to test the tracking algorithms. The test setup which was used to acquire the three-dimensional experimental data is described, along with the results from both of the tracking routines which were used to analyze the experimental data. (author)

  4. Three-dimensional simulations of resistance spot welding

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Zhang, Wenqi; Perret, William

    2014-01-01

    This paper draws from the fundamentals of electro-thermo-mechanical coupling to the main aspects of finite element implementation and three-dimensional modelling of resistance welding. A new simulation environment is proposed in order to perform three-dimensional simulations and optimization...... of resistance welding together with the simulations of conventional and special-purpose quasi-static mechanical tests. Three-dimensional simulations of resistance welding consider the electrical, thermal, mechanical and metallurgical characteristics of the material as well as the operating conditions...... of the welding machines. Simulations of the mechanical tests take into account material softening due to the accumulation of ductile damage and cover conventional tests, such as tensile–shear tests, cross-tension test and peel tests, as well as the possibility of special-purpose tests designed by the users...

  5. Application of three-dimensional CT reconstruction cranioplasty

    International Nuclear Information System (INIS)

    Yan Shuli; Yun Yongxing; Wan Kunming; Qiu Jian

    2011-01-01

    Objective: To study the application of three-dimensional CT reconstruction in cranioplasty. Methods: 46 patients with skull defect were divided into two group. One group underwent CT examination and three-dimensional reconstruction, and then the Titanium nets production company manufactured corresponding titanium meshes were shaped those data before the operation. The other group received traditional operation in which titanium meshes were shaped during operation. The average time of operation were compared. Results: The average time of operation of the first group is 86.6±13.6 mins, and that of the second group is 115±15.0 mins. The difference of average operation time between the two groups was statistically significant. Conclusion: Three-dimensional CT reconstruction techniques contribute to shorten the average operation time, reduce the intensity of neurosurgeon's work and the patien's risk. (authors)

  6. Eustachian tube three-dimensional reconstruction of secretory otitis media

    International Nuclear Information System (INIS)

    Yu Yafeng; Zhou Weirong; Bao Xueping; Li Min; Hu Zhenmin

    2006-01-01

    Objective: To study relationship between Eustachian tube and secretory otitis media and to explore the pathogeny of secretory otitis by three-dimensional reconstruction of Eustachian tube. Methods: Thirty cases of secretory otitis media (male 19, female 11) were selected randomly. Everyone was checked by otoscope and audiometry. Their bilateral Eustachian tubes were scanning by helix CT while making Valsalva's action. All images were passed on to work station to make three-dimensional reconstruction. Results: Four patients were found have Eustachian tube diseases, while most of patients' Eustachian tubes ventilated normally. Conclusions: Three-dimensional reconstruction of Eustachian tube can open out some pathogens of some secretory otitis medias. It will be helpful to diagnosis and therapy of secretory otitis media. (authors)

  7. Three-dimensional CT of the pediatric spine

    International Nuclear Information System (INIS)

    Starshak, R.J.; Crawford, C.R.; Waisman, R.C.; Sty, J.R.

    1987-01-01

    CT of the spine has been shown to be useful in evaluating congenital, neoplastic, inflammatory, and traumatic lesions. Any portion of the neural arch may be involved by these disease processes. However, the complex nature of the spinal column can make evaluation of these abnormalities difficult on axial CT. This is especially true if the spine is distorted by scoliosis, kyphosis, or lordosis. The principal advantage of three-dimensional CT is its ability to display the surface relationships of complicated objects. The complexity of the spinal axis makes it ideal for study with three-dimensional CT. This presentation illustrates the advantages and drawbacks of three-dimensional CT in spinal abnormalities in children

  8. Two- and three-dimensional CT analysis of ankle fractures

    International Nuclear Information System (INIS)

    Magid, D.; Fishman, E.K.; Ney, D.R.; Kuhlman, J.E.

    1988-01-01

    CT with coronal and sagittal reformatting (two-dimensional CT) and animated volumetric image rendering (three-dimensional CT) was used to assess ankle fractures. Partial volume limits transaxial CT in assessments of horizontally oriented structures. Two-dimensional CT, being orthogonal to the plafond, superior mortise, talar dome, and tibial epiphysis, often provides the most clinically useful images. Two-dimensional CT is most useful in characterizing potentially confusing fractures, such as Tillaux (anterior tubercle), triplane, osteochondral talar dome, or nondisplaced talar neck fractures, and it is the best study to confirm intraarticular fragments. Two-and three-dimensional CT best indicate the percentage of articular surface involvement and best demonstrate postoperative results or complications (hardware migration, residual step-off, delayed union, DJD, AVN, etc). Animated three-dimensional images are the preferred means of integrating the two-dimensional findings for surgical planning, as these images more closely simulate the clinical problem

  9. Prognostic value of three-dimensional ultrasound for fetal hydronephrosis

    Science.gov (United States)

    WANG, JUNMEI; YING, WEIWEN; TANG, DAXING; YANG, LIMING; LIU, DONGSHENG; LIU, YUANHUI; PAN, JIAOE; XIE, XING

    2015-01-01

    The present study evaluated the prognostic value of three-dimensional ultrasound for fetal hydronephrosis. Pregnant females with fetal hydronephrosis were enrolled and a novel three-dimensional ultrasound indicator, renal parenchymal volume/kidney volume, was introduced to predict the postnatal prognosis of fetal hydronephrosis in comparison with commonly used ultrasound indicators. All ultrasound indicators of fetal hydronephrosis could predict whether postnatal surgery was required for fetal hydronephrosis; however, the predictive performance of renal parenchymal volume/kidney volume measurements as an individual indicator was the highest. In conclusion, ultrasound is important in predicting whether postnatal surgery is required for fetal hydronephrosis, and the three-dimensional ultrasound indicator renal parenchymal volume/kidney volume has a high predictive performance. Furthermore, the majority of cases of fetal hydronephrosis spontaneously regress subsequent to birth, and the regression time is closely associated with ultrasound indicators. PMID:25667626

  10. A method of image improvement in three-dimensional imaging

    International Nuclear Information System (INIS)

    Suto, Yasuzo; Huang, Tewen; Furuhata, Kentaro; Uchino, Masafumi.

    1988-01-01

    In general, image interpolation is required when the surface configurations of such structures as bones and organs are three-dimensionally constructed from the multi-sliced images obtained by CT. Image interpolation is a processing method whereby an artificial image is inserted between two adjacent slices to make spatial resolution equal to slice resolution in appearance. Such image interpolation makes it possible to increase the image quality of the constructed three-dimensional image. In our newly-developed algorithm, we have converted the presently and subsequently sliced images to distance images, and generated the interpolation images from these two distance images. As a result, compared with the previous method, three-dimensional images with better image quality have been constructed. (author)

  11. Three-dimensional, three-component wall-PIV

    Science.gov (United States)

    Berthe, André; Kondermann, Daniel; Christensen, Carolyn; Goubergrits, Leonid; Garbe, Christoph; Affeld, Klaus; Kertzscher, Ulrich

    2010-06-01

    This paper describes a new time-resolved three-dimensional, three-component (3D-3C) measurement technique called wall-PIV. It was developed to assess near wall flow fields and shear rates near non-planar surfaces. The method is based on light absorption according to Beer-Lambert’s law. The fluid containing a molecular dye and seeded with buoyant particles is illuminated by a monochromatic, diffuse light. Due to the dye, the depth of view is limited to the near wall layer. The three-dimensional particle positions can be reconstructed by the intensities of the particle’s projection on an image sensor. The flow estimation is performed by a new algorithm, based on learned particle trajectories. Possible sources of measurement errors related to the wall-PIV technique are analyzed. The accuracy analysis was based on single particle experiments and a three-dimensional artificial data set simulating a rotating sphere.

  12. A three-dimensional field solutions of Halbach

    International Nuclear Information System (INIS)

    Chen Jizhong; Xiao Jijun; Zhang Yiming; Xu Chunyan

    2008-01-01

    A three-dimensional field solutions are presented for Halback cylinder magnet. Based on Ampere equivalent current methods, the permanent magnets are taken as distributing of current density. For getting the three-dimensional field solution of ideal polarized permanent magnets, the solution method entails the use of the vector potential and involves the closed-form integration of the free-space Green's function. The programmed field solution are ideal for performing rapid parametric studies of the dipole Halback cylinder magnets made from rare earth materials. The field solutions are verified by both an analytical two-dimensional algorithm and three-dimensional finite element software. A rapid method is presented for extensive analyzing and optimizing Halbach cylinder magnet. (authors)

  13. Computational methods for three-dimensional microscopy reconstruction

    CERN Document Server

    Frank, Joachim

    2014-01-01

    Approaches to the recovery of three-dimensional information on a biological object, which are often formulated or implemented initially in an intuitive way, are concisely described here based on physical models of the object and the image-formation process. Both three-dimensional electron microscopy and X-ray tomography can be captured in the same mathematical framework, leading to closely-related computational approaches, but the methodologies differ in detail and hence pose different challenges. The editors of this volume, Gabor T. Herman and Joachim Frank, are experts in the respective methodologies and present research at the forefront of biological imaging and structural biology.   Computational Methods for Three-Dimensional Microscopy Reconstruction will serve as a useful resource for scholars interested in the development of computational methods for structural biology and cell biology, particularly in the area of 3D imaging and modeling.

  14. Three-dimensional CT imaging of soft-tissue anatomy

    International Nuclear Information System (INIS)

    Fishman, E.K.; Ney, D.R.; Magid, D.; Kuhlman, J.E.

    1988-01-01

    Three-dimensional display of computed tomographic data has been limited to skeletal structures. This was in part related to the reconstruction algorithm used, which relied on a binary classification scheme. A new algorithm, volumetric rendering with percentage classification, provides the ability to display three-dimensional images of muscle and soft tissue. A review was conducted of images in 35 cases in which muscle and/or soft tissue were part of the clinical problem. In all cases, individual muscle groups could be clearly identified and discriminated. Branching vessels in the range of 2.3 mm could be identified. Similarly, lymph nodes could be clearly defined. High-resolution three-dimensional images were found to be useful both in providing an increased understanding of complex muscle and soft tissue anatomy and in surgical planning

  15. Three-dimensional quadrupole lenses made with permanent magnets

    International Nuclear Information System (INIS)

    Ivanov, A.S.

    1984-01-01

    The performance of accelerator systems with quadrupole magnets can be improved by using permanent magnets in quadrupole lenses. This requires better methods for treating the three-dimensional nature of the magnetic fields and the nonlinear characteristics of the magnets. A numerical method is described for simulating three-dimensional magnetic fields and used to analyze quadrupole lenses and doublets with permanent magnets. The results, which are confirmed experimentally, indicate that both the quadrupole magnetic gradient and the effective field length are changed in permanent-magnet quadrupole lenses when the pole lengths and the gap between the lenses are varied while the other characteristics of the magnets remain unchanged

  16. Three dimensional imaging technique for laser-plasma diagnostics

    International Nuclear Information System (INIS)

    Jiang Shaoen; Zheng Zhijian; Liu Zhongli

    2001-01-01

    A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments

  17. Three-dimensional flow and turbulence structure in electrostatic precipitator

    DEFF Research Database (Denmark)

    Ullum, Thorvald Uhrskov; Larsen, Poul Scheel; Özcan, Oktay

    2002-01-01

    Stereo PIV is employed to study the three-dimensional velocity and turbulence fields in a laboratory model of a negative corona, barbed-wire, smooth-plate, electrostatic precipitator (figure 1). The study is focused on determining the parametric effects of axial development, mean current density Jm...... and bulk velocity U0 on secondary flows and turbulence levels and structures due to the action of the three-dimensional electrostatic field on the charged gas. At constant bulk velocity (U0 = 1 m/s) and current density (Jm = 0.4 mA/m2), secondary flows in the form of rolls of axial vorticity with swirl...

  18. Three-dimensional wax patterning of paper fluidic devices.

    Science.gov (United States)

    Renault, Christophe; Koehne, Jessica; Ricco, Antonio J; Crooks, Richard M

    2014-06-17

    In this paper we describe a method for three-dimensional wax patterning of microfluidic paper-based analytical devices (μPADs). The method is rooted in the fundamental details of wax transport in paper and provides a simple way to fabricate complex channel architectures such as hemichannels and fully enclosed channels. We show that three-dimensional μPADs can be fabricated with half as much paper by using hemichannels rather than ordinary open channels. We also provide evidence that fully enclosed channels are efficiently isolated from the exterior environment, decreasing contamination risks, simplifying the handling of the device, and slowing evaporation of solvents.

  19. Three dimensional investigation of oceanic active faults. A demonstration survey

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Seizo; Kishimoto, Kiyoyuki; Kuramoto, Shinichi; Sato, Mikio [Geological Survey of Japan, Tsukuba, Ibaraki (Japan)

    1998-02-01

    In order to upgrade probability of activity and action potential evaluation of oceanic active faults which have some important effects on nuclear facilities, trench type oceanic active fault was investigated three dimensionally. Contents of the investigation were high precision sea bottom topographic survey and sea bottom back scattering wave image data observation by using a sea bottom topography acoustic imaginator. And, by high resolution earthquake wave survey, high precision survey of an active fault under sea bottom was conducted to detect oceanic active faults three-dimensionally. Furthermore, the generally issued data were summarized to promote to construct a data base for evaluating the active faults. (G.K.)

  20. Implementation of three dimensional treatment planning system for external radiotherapy

    International Nuclear Information System (INIS)

    Major, Tibor; Kurup, P.G.G.; Stumpf, Janos

    1997-01-01

    A three dimensional (3D) treatment planning system was installed at Apollo Cancer Hospital, Chennai, India in 1995. This paper gives a short description of the system including hardware components, calculation algorithm, measured data requirements and specific three dimensional features. The concept and the structure of the system are shortly described. The first impressions along with critical opinions and the experiences are gained during the data acquisition are mentioned. Some improvements in the user interface are suggested. It is emphasized that although a 3D system offers more detailed and accurate dose distributions compared to a 2D system, it also introduces a greatly increased workload for the planning staff. (author)

  1. Resonance fluorescence based two- and three-dimensional atom localization

    Science.gov (United States)

    Wahab, Abdul; Rahmatullah; Qamar, Sajid

    2016-06-01

    Two- and three-dimensional atom localization in a two-level atom-field system via resonance fluorescence is suggested. For the two-dimensional localization, the atom interacts with two orthogonal standing-wave fields, whereas for the three-dimensional atom localization, the atom interacts with three orthogonal standing-wave fields. The effect of the detuning and phase shifts associated with the corresponding standing-wave fields is investigated. A precision enhancement in position measurement of the single atom can be noticed via the control of the detuning and phase shifts.

  2. Three dimensional imaging technique for laser-plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Shaoen, Jiang; Zhijian, Zheng; Zhongli, Liu [China Academy of Engineering Physics, Chengdu (China)

    2001-04-01

    A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments.

  3. Three dimensional investigation of oceanic active faults. A demonstration survey

    International Nuclear Information System (INIS)

    Nakao, Seizo; Kishimoto, Kiyoyuki; Kuramoto, Shinichi; Sato, Mikio

    1998-01-01

    In order to upgrade probability of activity and action potential evaluation of oceanic active faults which have some important effects on nuclear facilities, trench type oceanic active fault was investigated three dimensionally. Contents of the investigation were high precision sea bottom topographic survey and sea bottom back scattering wave image data observation by using a sea bottom topography acoustic imaginator. And, by high resolution earthquake wave survey, high precision survey of an active fault under sea bottom was conducted to detect oceanic active faults three-dimensionally. Furthermore, the generally issued data were summarized to promote to construct a data base for evaluating the active faults. (G.K.)

  4. Three-dimensional Reciprocal Structures: Morphology, Concepts, Generative Rules

    DEFF Research Database (Denmark)

    Parigi, Dario; Pugnale, Alberto

    2012-01-01

    , causing every configuration to develop naturally out-of the plane. The structures presented here were developed and built by the students of the Master of Science in “Architectural Design” during a two week long workshop organized at Aalborg University in the fall semester 2011.......This paper present seven different three dimensional structures based on the principle of structural reciprocity with superimposition joint and standardized un-notched elements. Such typology could be regarded as being intrinsically three-dimensional because elements sit one of the top of the other...

  5. Three dimensional printed calcium phosphate and poly(caprolactone) composites with improved mechanical properties and preserved microstructure.

    Science.gov (United States)

    Vella, Joseph B; Trombetta, Ryan P; Hoffman, Michael D; Inzana, Jason; Awad, Hani; Benoit, Danielle S W

    2018-03-01

    Biphasic calcium phosphate scaffolds formed via three dimensional (3D) printing technology to exhibit porosity and chemical resorbability to promote osseointegration often lack the strength and toughness required to withstand loading in bone tissue engineering applications. Herein, sintering and CaP:poly(caprolactone) (PCL) composite formation were explored to improve 3D printed scaffold strength and toughness. Hydroxyapatite and α-tricalcium phosphate (α-TCP) biphasic calcium powders were printed using phosphoric acid binder, which generated monetite and hydroxyapatite scaffolds. Upon sintering, evolution of β-TCP was observed along with an increase in flexural strength and modulus but no effect on fracture toughness was observed. Furthermore, scaffold porosity increased with sintering. Additionally, two techniques of PCL composite formation were employed: postprint precipitation and 3D print codeposition to further augment scaffold mechanical properties. While both techniques significantly improved flexural strength, flexural modulus, and fracture toughness under most conditions explored, precipitation yielded more substantial increases in these properties, which is attributed to better continuity of the PCL phase. However, precipitation also compromised surface porosity due to PCL passivation of the calcium phosphate surface, which may subsequently hinder scaffold integration and bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 663-672, 2018. © 2017 Wiley Periodicals, Inc.

  6. Surface modification of poly(D,L-lactic acid) scaffolds for orthopedic applications: a biocompatible, nondestructive route via diazonium chemistry.

    Science.gov (United States)

    Mahjoubi, Hesameddin; Kinsella, Joseph M; Murshed, Monzur; Cerruti, Marta

    2014-07-09

    Scaffolds made with synthetic polymers such as polyesters are commonly used in bone tissue engineering. However, their hydrophobicity and the lack of specific functionalities make their surface not ideal for cell adhesion and growth. Surface modification of these materials is thus crucial to enhance the scaffold's integration in the body. Different surface modification techniques have been developed to improve scaffold biocompatibility. Here we show that diazonium chemistry can be used to modify the outer and inner surfaces of three-dimensional poly(D,L-lactic acid) (PDLLA) scaffolds with phosphonate groups, using a simple two-step method. By changing reaction time and impregnation procedure, we were able to tune the concentration of phosphonate groups present on the scaffolds, without degrading the PDLLA matrix. To test the effectiveness of this modification, we immersed the scaffolds in simulated body fluid, and characterized them with scanning electron microscopy, X-ray photoelectron spectroscopy, Raman, and infrared spectroscopy. Our results showed that a layer of hydroxyapatite particles was formed on all scaffolds after 2 and 4 weeks of immersion; however, the precipitation was faster and in larger amounts on the phosphonate-modified than on the bare PDLLA scaffolds. Both osteogenic MC3T3-E1 and chondrogenic ATDC5 cell lines showed increased cell viability/metabolic activity when grown on a phosphonated PDLLA surface in comparison to a control PDLLA surface. Also, more calcium-containing minerals were deposited by cultures grown on phosphonated PDLLA, thus showing the pro-mineralization properties of the proposed modification. This work introduces diazonium chemistry as a simple and biocompatible technique to modify scaffold surfaces, allowing to covalently and homogeneously bind a number of functional groups without degrading the scaffold's polymeric matrix.

  7. Acid-base properties of complexes with three-dimensional polyligands. Complexes with three-dimensional polyphosphoric acids

    International Nuclear Information System (INIS)

    Kopylova, V.D.; Bojko, Eh.T.; Saldadze, K.M.

    1985-01-01

    By the method of potentiometric titration acid-base properties of uranyl (2) complexes with three-dimensional polyphosphoric acids, KRF-8p, KF-1, KF-7 prepared by phosphorylation of copolymer of styrene and divinylbenzene or saponification of the copolymers of di-2,2'-chloroethyl ester of vinylphosphonic acid with divinyl benzene are studied. It is shown that in case of formation in the phase of three-dimensional polyphosphoric acids of UO 2 2+ complexes with the growth of bond covalence of metal ion-phosphonic group the acidjty of the second hydroxyl of the phosphonic group increases

  8. Three Dimensional Polarimetric Neutron Tomography of Magnetic Fields

    DEFF Research Database (Denmark)

    Sales, Morten; Strobl, Markus; Shinohara, Takenao

    2018-01-01

    Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non-destructively wi......Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non...... and reconstructed, thereby providing the proof-of-principle of a technique able to reveal hitherto unobtainable information on the magnetic fields in the bulk of materials and devices, due to a high degree of penetration into many materials, including metals, and the sensitivity of neutron polarisation to magnetic...... fields. The technique puts the potential of the ToF time structure of pulsed neutron sources to full use in order to optimise the recorded information quality and reduce measurement time....

  9. Three-Dimensional Extension of a Digital Library Service System

    Science.gov (United States)

    Xiao, Long

    2010-01-01

    Purpose: The paper aims to provide an overall methodology and case study for the innovation and extension of a digital library, especially the service system. Design/methodology/approach: Based on the three-dimensional structure theory of the information service industry, this paper combines a comprehensive analysis with the practical experiences…

  10. Quantum field between moving mirrors: A three dimensional example

    Science.gov (United States)

    Hacyan, S.; Jauregui, Roco; Villarreal, Carlos

    1995-01-01

    The scalar quantum field uniformly moving plates in three dimensional space is studied. Field equations for Dirichlet boundary conditions are solved exactly. Comparison of the resulting wavefunctions with their instantaneous static counterpart is performed via Bogolubov coefficients. Unlike the one dimensional problem, 'particle' creation as well as squeezing may occur. The time dependent Casimir energy is also evaluated.

  11. Three-dimensional fractal geometry for gas permeation in microchannels

    NARCIS (Netherlands)

    Malankowska, Magdalena; Schlautmann, Stefan; Berenschot, Erwin J.W.; Tiggelaar, Roald M.; Pina, Maria Pilar; Mallada, Reyes; Tas, Niels R.; Gardeniers, Han

    2018-01-01

    The novel concept of a microfluidic chip with an integrated three-dimensional fractal geometry with nanopores, acting as a gas transport membrane, is presented. The method of engineering the 3D fractal structure is based on a combination of anisotropic etching of silicon and corner lithography. The

  12. A DETERMINISTIC METHOD FOR TRANSIENT, THREE-DIMENSIONAL NUETRON TRANSPORT

    International Nuclear Information System (INIS)

    S. GOLUOGLU, C. BENTLEY, R. DEMEGLIO, M. DUNN, K. NORTON, R. PEVEY I.SUSLOV AND H.L. DODDS

    1998-01-01

    A deterministic method for solving the time-dependent, three-dimensional Boltzmam transport equation with explicit representation of delayed neutrons has been developed and evaluated. The methodology used in this study for the time variable of the neutron flux is known as the improved quasi-static (IQS) method. The position, energy, and angle-dependent neutron flux is computed deterministically by using the three-dimensional discrete ordinates code TORT. This paper briefly describes the methodology and selected results. The code developed at the University of Tennessee based on this methodology is called TDTORT. TDTORT can be used to model transients involving voided and/or strongly absorbing regions that require transport theory for accuracy. This code can also be used to model either small high-leakage systems, such as space reactors, or asymmetric control rod movements. TDTORT can model step, ramp, step followed by another step, and step followed by ramp type perturbations. It can also model columnwise rod movement can also be modeled. A special case of columnwise rod movement in a three-dimensional model of a boiling water reactor (BWR) with simple adiabatic feedback is also included. TDTORT is verified through several transient one-dimensional, two-dimensional, and three-dimensional benchmark problems. The results show that the transport methodology and corresponding code developed in this work have sufficient accuracy and speed for computing the dynamic behavior of complex multidimensional neutronic systems

  13. Scattering and conductance quantization in three-dimensional metal nanocontacts

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Jacobsen, Karsten Wedel; Nørskov, Jens Kehlet

    1997-01-01

    The transmission through three-dimensional nanocontacts is calculated in the presence of localized scattering centers and boundary scattering using a coupled-channel recursion method. Simple confining potentials are used to investigate how robust the observation of quantized conductance is with r...

  14. Three-dimensional reconstruction of the pigeon inner ear

    NARCIS (Netherlands)

    Hofman, R.; Segenhout, J. M.; Wit, H. P.

    2009-01-01

    Three-dimensional reconstructions of the inner ear of the pigeon (Columba livia domestica), from two-dimensional images, obtained with (conventional) light microscopy or orthogonal-plane fluorescence optical sectioning (OPFOS), are presented. The results are compared with available information on

  15. A note on the three dimensional sine--Gordon equation

    OpenAIRE

    Shariati, Ahmad

    1996-01-01

    Using a simple ansatz for the solutions of the three dimensional generalization of the sine--Gordon and Toda model introduced by Konopelchenko and Rogers, a class of solutions is found by elementary methods. It is also shown that these equations are not evolution equations in the sense that solution to the initial value problem is not unique.

  16. Three-dimensional reacting shock–bubble interaction

    NARCIS (Netherlands)

    Diegelmann, Felix; Hickel, S.; Adams, Nikolaus A.

    2017-01-01

    We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric

  17. Polycrystalline diamond detectors with three-dimensional electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, S., E-mail: lagomarsino@fi.infn.it [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bellini, M. [INO-CNR Firenze, Largo E. Fermi 6, 50125 Firenze (Italy); Brianzi, M. [INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Carzino, R. [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia, Genova, Via Morego 30, 16163 Genova (Italy); Cindro, V. [Joseph Stefan Institute, Jamova Cesta 39, 1000 Ljubljana (Slovenia); Corsi, C. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); LENS Firenze, Via N. Carrara 1, 50019 Sesto Fiorentino (Italy); Morozzi, A.; Passeri, D. [INFN Perugia, Perugia (Italy); Università degli Studi di Perugia, Dipartimento di Ingegneria, via G. Duranti 93, 06125 Perugia (Italy); Sciortino, S. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

    2015-10-01

    The three-dimensional concept in diamond detectors has been applied, so far, to high quality single-crystal material, in order to test this technology in the best available conditions. However, its application to polycrystalline chemical vapor deposited diamond could be desirable for two reasons: first, the short inter-electrode distance of three-dimensional detectors should improve the intrinsically lower collection efficiency of polycrystalline diamond, and second, at high levels of radiation damage the performances of the poly-crystal material are not expected to be much lower than those of the single crystal one. We report on the fabrication and test of three-dimensional polycrystalline diamond detectors with several inter-electrode distances, and we demonstrate that their collection efficiency is equal or higher than that obtained with conventional planar detectors fabricated with the same material. - Highlights: • Pulsed laser fabrication of polycristalline diamond detectors with 3D electrodes. • Measurement of the charge collection efficiency (CCE) under beta irradiation. • Comparation between the CCE of 3D and conventional planar diamond sensors. • A rationale for the behavior of three-dimensional and planar sensors is given.

  18. Loop expansion in massless three-dimensional QED

    International Nuclear Information System (INIS)

    Guendelman, E.I.; Radulovic, Z.M.

    1983-01-01

    It is shown how the loop expansion in massless three-dimensional QED can be made finite, up to three loops, by absorbing the infrared divergences in a gauge-fixing term. The same method removes leading and first subleading singularities to all orders of perturbation theory, and all singularities of the fermion self-energy to four loops

  19. Three-dimensional models of the tracheostoma using stereolithography

    NARCIS (Netherlands)

    Grolman, W.; Schouwenburg, P. F.; Verbeeten, B.; de Boer, M. F.; Meeuwis, C. A.

    1995-01-01

    The availability of an accurate three-dimensional (3-D) model of the tracheostoma and trachea of the laryngectomy patient would be of great help in prototyping of endotracheal prostheses. Stereolithography has been described for skull and jaw models but never for soft-tissue reconstructions of the

  20. Three-dimensional ultrasound strain imaging of skeletal muscles

    NARCIS (Netherlands)

    Gijsbertse, Kaj; Sprengers, Andre M.; Nillesen, Maartje; Hansen, Hendrik H.G.; Verdonschot, Nico; De Korte, Chris L.

    2015-01-01

    Muscle contraction is characterized by large deformation and translation, which requires a multi-dimensional imaging modality to reveal its behavior. Previous work on ultrasound strain imaging of the muscle contraction was limited to 2D and bi-plane techniques. In this study, a three-dimensional

  1. Kondo effect in three-dimensional Dirac and Weyl systems

    NARCIS (Netherlands)

    Mitchell, Andrew K.; Fritz, Lars

    2015-01-01

    Magnetic impurities in three-dimensional Dirac and Weyl systems are shown to exhibit a fascinatingly diverse range of Kondo physics, with distinctive experimental spectroscopic signatures. When the Fermi level is precisely at the Dirac point, Dirac semimetals are in fact unlikely candidates for a

  2. Generation of a Desired Three-Dimensional Electromagnetic Field

    DEFF Research Database (Denmark)

    2005-01-01

    The present invention relates to a method and a system for synthesizing a prescribed three-dimensional electromagnetic field based on generalized phase contrast imaging. Such a method and apparatus may be utilized in advanced optical micro and nano-manipulation, such as by provision of a multiple...

  3. Three-dimensional coupled double-distribution-function lattice ...

    Indian Academy of Sciences (India)

    Ruo-Fan Qiu

    2017-11-14

    Nov 14, 2017 ... Abstract. Two three-dimensional (3D) lattice Boltzmann models in the framework of coupled double-distribution- function approach for compressible flows, in which specific-heat ratio and Prandtl number can be adjustable, are developed in this paper. The main differences between the two models are ...

  4. Three-dimensional face shape in Fabry disease

    NARCIS (Netherlands)

    Cox-Brinkman, Josanne; Vedder, Anouk; Hollak, Carla; Richfield, Linda; Mehta, Atul; Orteu, Kate; Wijburg, Frits; Hammond, Peter

    2007-01-01

    Facial dysmorphology is an important feature in several lysosomal storage disorders. Although in Fabry disease facial dysmorphism is not a prominent sign, minor facial abnormalities have been previously reported. By analysing three-dimensional images of faces, we quantified facial dysmorphology in a

  5. Three dimensional reconstruction of tomographic images of the retina

    International Nuclear Information System (INIS)

    Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

    2007-01-01

    The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

  6. Numerical Investigation of Three-dimensional Instability of Standing Waves

    Science.gov (United States)

    Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

    2002-11-01

    We study the three-dimensional instability of finite-amplitude standing waves under the influence of gravity using the transition matrix method. For accurate calculation of the transition matrices, we apply an efficient high-order spectral element method for nonlinear wave dynamics in complex domain. We consider two types of standing waves: (a) plane standing waves; and (b) standing waves in a circular tank. For the former, in addition to the confirmation of the side-band-like instability, we find a new three-dimensional instability for arbitrary base standing waves. The dominant component of the unstable disturbance is an oblique standing wave, with an arbitrary angle relative to the base flow, whose frequency is approximately equal to that of the base standing wave. Based on direct simulations, we confirm such a three-dimensional instability and show the occurrence of the Fermi-Pasta-Ulam recurrence phenomenon during nonlinear evolution. For the latter, we find that beyond a threshold wave steepness, the standing wave with frequency Ω becomes unstable to a small three-dimensional disturbance, which contains two dominant standing-wave components with frequencies ω1 and ω_2, provided that 2Ω ω1 + ω_2. The threshold wave steepness is found to decrease/increase as the radial/azimuthal wavenumber of the base standing wave increases. We show that the instability of standing waves in rectangular and circular tanks is caused by third-order quartet resonances between base flow and disturbance.

  7. Wave packet construction in three-dimensional quantum billiards ...

    Indian Academy of Sciences (India)

    E-mail: mannu_711@yahoo.co.in. MS received 14 ... The motivation to extend the study to a three-dimensional (3D) system is .... with a GWP centred around the central value of the principle quantum number n0 instead of a GWP ...... Cubical and parallelepiped billiards are the potential candidates for the creation of arti-.

  8. Green function of a three-dimensional Wick problem

    International Nuclear Information System (INIS)

    Matveev, V.A.

    1988-01-01

    An exact solution of a three-dimensional Coulomb Wick-Cutkovsky problem has been obtained which possesses the hidden 0(4)-symmetry. Here we shell give the derivation of the corresponding Green function and consider its connection with the asymptoric behaviour of the scattering amplitude. 9 refs

  9. Effects of forcing in three-dimensional turbulent flows

    NARCIS (Netherlands)

    Biferale, L.; Lanotte, A.; Toschi, F.

    2004-01-01

    We present the results of a numerical investigation of three-dimensional homogeneous and isotropic turbulence, stirred by a random forcing with a power-law spectrum, Ef(k)~k3-y. Numerical simulations are performed at different resolutions up to 5123. We show that at varying the spectrum slope y,

  10. Three-Dimensional Gauge Theories and ADE Monopoles

    OpenAIRE

    Tong, David

    1998-01-01

    We study three-dimensional N=4 gauge theories with product gauge groups constructed from ADE Dynkin diagrams. One-loop corrections to the metric on the Coulomb branch are shown to coincide with the metric on the moduli space of well-seperated ADE monopoles. We propose that this correspondence is exact.

  11. Three-dimensional simulations of free-electron laser physics

    International Nuclear Information System (INIS)

    McVey, B.D.

    1985-09-01

    A computer code has been developed to simulate three-dimensional free-electron laser physics. A mathematical formulation of the FEL equations is presented, and the numerical solution of the problem is described. Sample results from the computer code are discussed. 23 refs., 6 figs., 2 tabs

  12. Three-dimensional organization of the human interphase nucleus

    NARCIS (Netherlands)

    T.A. Knoch (Tobias); C. Münkel (Christian); W. Waldeck (Waldemar); J. Langowski (Jörg)

    2000-01-01

    textabstractDespite the successful linear sequencing of the human genome its three-dimensional structure is widely unknown, although it is important for gene regulation and replication. For a long time the interphase nucleus has been viewed as a 'spaghetti soup' of DNA without much internal

  13. Birkhoff's Theorem for Three-Dimensional AdS Gravity

    OpenAIRE

    Ayón-Beato, Eloy; Martínez, Cristián; Zanelli, Jorge

    2004-01-01

    All three-dimensional matter-free spacetimes with negative cosmological constant, compatible with cyclic symmetry are identified. The only cyclic solutions are the 2+1 (BTZ) black hole with SO(2) x R isometry, and the self-dual Coussaert-Henneaux spacetimes, with isometry groups SO(2) x SO(2,1) or SO(2) x SO(2).

  14. Fabrication of three-dimensional carbon microelectrodes for electrochemical sensing

    DEFF Research Database (Denmark)

    Hemanth, Suhith

    Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. The aim of the research work carried out in this thesis was to develop three-dimensional (3D) carbon microelectrodes for electrochemical applications. Three different fabrica...

  15. Three-dimensional echocardiographic assessment of the repaired mitral valve.

    Science.gov (United States)

    Maslow, Andrew; Mahmood, Feroze; Poppas, Athena; Singh, Arun

    2014-02-01

    This study examined the geometric changes of the mitral valve (MV) after repair using conventional and three-dimensional echocardiography. Prospective evaluation of consecutive patients undergoing mitral valve repair. Tertiary care university hospital. Fifty consecutive patients scheduled for elective repair of the mitral valve for regurgitant disease. Intraoperative transesophageal echocardiography. Assessments of valve area (MVA) were performed using two-dimensional planimetry (2D-Plan), pressure half-time (PHT), and three-dimensional planimetry (3D-Plan). In addition, the direction of ventricular inflow was assessed from the three-dimensional imaging. Good correlations (r = 0.83) and agreement (-0.08 +/- 0.43 cm(2)) were seen between the MVA measured with 3D-Plan and PHT, and were better than either compared to 2D-Plan. MVAs were smaller after repair of functional disease repaired with an annuloplasty ring. After repair, ventricular inflow was directed toward the lateral ventricular wall. Subgroup analysis showed that the change in inflow angle was not different after repair of functional disease (168 to 171 degrees) as compared to those presenting with degenerative disease (168 to 148 degrees; p<0.0001). Three-dimensional imaging provides caregivers with a unique ability to assess changes in valve function after mitral valve repair. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Mathematical modeling of three-dimensional images in emission tomography

    International Nuclear Information System (INIS)

    Koblik, Yu.N.; Khugaev, A. V.; Mktchyan, G.A.; Ioannou, P.; Dimovasili, E.

    2002-01-01

    The model of processing results of three-dimensional measurements in positron-emissive tomograph is proposed in this work. The algorithm of construction and visualization of phantom objects of arbitrary shape was developed and its concrete realization in view of program packet for PC was carried out

  17. Three-dimensional image reconstruction from stereo DSA

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Umehara, Takayoshi; Yamada, Eiji; Inaba, Tomohiro; Itou, Hiroshi

    1999-01-01

    The technique of interventional radiology has spread rapidly in recent years, and three-dimensional information from blood vessel images is being sought to enhance examinations. Stereo digital subtraction angiography (DSA) and rotational DSA were developed for that purpose. However, it is difficult with stereo DSA to observe the image pair during examination and to obtain positional information on blood vessels. Further, the exposure dose is increased in rotational DSA when many mask images need to be collected, and the patient is required to hold his or her breath for a long duration. We therefore devised a technique to construct three-dimensional blood vessel images by employing geometrical information extracted from stereo DSA images using the right and left images. We used a judgment method based on the correlation coefficient, although we had to extract an equal blood vessel from the right and left images to determine the three-dimensional coordinates of the blood vessel. The reconstructed three-dimensional blood vessels were projected from various angles, again by using a virtual focus, and new images were created. These image groups were displayed as rotational images by the animation display function incorporated in the DSA device. This system can observe blood vessel images of the same phase at a free angle, although the image quality is inferior to that of rotational DSA. In addition, because collection of the mask images is reduced, exposure dose can be decreased. Further, the system offers enhanced safety because no mechanical movement of the imaging system is involved. (author)

  18. Three-dimensional computer models of electrospinning systems

    Directory of Open Access Journals (Sweden)

    Smółka Krzysztof

    2017-12-01

    Full Text Available Electrospinning is a very interesting method that allows the fabrication of continuous fibers with diameters down to a few nanometers. This paper presents an overview of electrospinning systems as well as their comparison using proposed three-dimensional parameterized numerical models. The presented solutions allow an analysis of the electric field distribution.

  19. Three-Dimensional Structure of CeO2 Nanocrystals

    DEFF Research Database (Denmark)

    Tan, Joyce Pei Ying; Tan, Hui Ru; Boothroyd, Chris

    2011-01-01

    Visualization of three-dimensional (3D) structures of materials at the nanometer scale can shed important information on the performance of their applications and provide insight into the growth mechanism of shape-controlled nanomaterials. In this paper, the 3D structures and growth pathway of Ce...

  20. Three dimensional simulated modelling of diffusion capacitance of ...

    African Journals Online (AJOL)

    A three dimensional (3-D) simulated modelling was developed to analyse the excess minority carrier density in the base of a polycrystalline bifacial silicon solar cell. The concept of junction recombination velocity was ado-pted to quantify carrier flow through the junction, and to examine the solar cell diffusion capacitance for ...

  1. Signal processing of eddy current three-dimensional maps

    International Nuclear Information System (INIS)

    Birac, C.; David, D.; Lamant, D.

    1987-01-01

    Digital processing of eddy current three-dimensional maps improves accuracy of detection: flattening, filtering, computing deconvolution, mapping new variables,.., give new possibilities for difficult test problems. With simulation of defects, probes, probe travels, it is now possible to compute new eddy current processes, without machining defects or building probes

  2. Backlund transformations and three-dimensional lattice equations

    NARCIS (Netherlands)

    Nijhoff, F.W.; Capel, H.W.; Wiersma, G.L.; Quispel, G.R.W.

    1984-01-01

    A (nonlocal) linear integral equation is studied, which allows for Bäcklund transformations in the measure. The compatibility of three of these transformations leads to an integrable nonlinear three-dimensional lattice equation. In appropriate continuum limits the two-dimensional Toda-lattice

  3. A Novel Three-Dimensional Tool for Teaching Human Neuroanatomy

    Science.gov (United States)

    Estevez, Maureen E.; Lindgren, Kristen A.; Bergethon, Peter R.

    2010-01-01

    Three-dimensional (3D) visualization of neuroanatomy can be challenging for medical students. This knowledge is essential in order for students to correlate cross-sectional neuroanatomy and whole brain specimens within neuroscience curricula and to interpret clinical and radiological information as clinicians or researchers. This study implemented…

  4. Oblique water entry of a three dimensional body

    Directory of Open Access Journals (Sweden)

    Scolan Yves-Marie

    2014-12-01

    Full Text Available The problem of the oblique water entry of a three dimensional body is considered. Wagner theory is the theoretical framework. Applications are discussed for an elliptic paraboloid entering an initially flat free surface. A dedicated experimental campaign yields a data base for comparisons. In the present analysis, pressure, force and dynamics of the wetted surface expansion are assessed.

  5. Splines under tension for gridding three-dimensional data

    International Nuclear Information System (INIS)

    Brand, H.R.; Frazer, J.W.

    1982-01-01

    By use of the splines-under-tension concept, a simple algorithm has been developed for the three-dimensional representation of nonuniformly spaced data. The representations provide useful information to the experimentalist when he is attempting to understand the results obtained in a self-adaptive experiment. The shortcomings of the algorithm are discussed as well as the advantages

  6. Approaching the Sequential and Three-Dimensional Organization of Genomes

    NARCIS (Netherlands)

    T.A. Knoch (Tobias)

    2006-01-01

    textabstractGenomes are one of the major foundations of life due to their role in information storage, process regulation and evolution. To achieve a deeper unterstanding of the human genome the three-dimensional organization of the human cell nucleus, the structural-, scaling- and dynamic

  7. Evaluation of three-dimensional virtual perception of garments

    Science.gov (United States)

    Aydoğdu, G.; Yeşilpinar, S.; Erdem, D.

    2017-10-01

    In recent years, three-dimensional design, dressing and simulation programs came into prominence in the textile industry. By these programs, the need to produce clothing samples for every design in design process has been eliminated. Clothing fit, design, pattern, fabric and accessory details and fabric drape features can be evaluated easily. Also, body size of virtual mannequin can be adjusted so more realistic simulations can be created. Moreover, three-dimensional virtual garment images created by these programs can be used while presenting the product to end-user instead of two-dimensional photograph images. In this study, a survey was carried out to investigate the visual perception of consumers. The survey was conducted for three different garment types, separately. Questions about gender, profession etc. was asked to the participants and expected them to compare real samples and artworks or three-dimensional virtual images of garments. When survey results were analyzed statistically, it is seen that demographic situation of participants does not affect visual perception and three-dimensional virtual garment images reflect the real sample characteristics better than artworks for each garment type. Also, it is reported that there is no perception difference depending on garment type between t-shirt, sweatshirt and tracksuit bottom.

  8. Materials science. Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling.

    Science.gov (United States)

    Xu, Sheng; Yan, Zheng; Jang, Kyung-In; Huang, Wen; Fu, Haoran; Kim, Jeonghyun; Wei, Zijun; Flavin, Matthew; McCracken, Joselle; Wang, Renhan; Badea, Adina; Liu, Yuhao; Xiao, Dongqing; Zhou, Guoyan; Lee, Jungwoo; Chung, Ha Uk; Cheng, Huanyu; Ren, Wen; Banks, Anthony; Li, Xiuling; Paik, Ungyu; Nuzzo, Ralph G; Huang, Yonggang; Zhang, Yihui; Rogers, John A

    2015-01-09

    Complex three-dimensional (3D) structures in biology (e.g., cytoskeletal webs, neural circuits, and vasculature networks) form naturally to provide essential functions in even the most basic forms of life. Compelling opportunities exist for analogous 3D architectures in human-made devices, but design options are constrained by existing capabilities in materials growth and assembly. We report routes to previously inaccessible classes of 3D constructs in advanced materials, including device-grade silicon. The schemes involve geometric transformation of 2D micro/nanostructures into extended 3D layouts by compressive buckling. Demonstrations include experimental and theoretical studies of more than 40 representative geometries, from single and multiple helices, toroids, and conical spirals to structures that resemble spherical baskets, cuboid cages, starbursts, flowers, scaffolds, fences, and frameworks, each with single- and/or multiple-level configurations. Copyright © 2015, American Association for the Advancement of Science.

  9. A Review of Current Clinical Applications of Three-Dimensional Printing in Spine Surgery.

    Science.gov (United States)

    Cho, Woojin; Job, Alan Varkey; Chen, Jing; Baek, Jung Hwan

    2018-02-01

    Three-dimensional (3D) printing is a transformative technology with a potentially wide range of applications in the field of orthopaedic spine surgery. This article aims to review the current applications, limitations, and future developments of 3D printing technology in orthopaedic spine surgery. Current preoperative applications of 3D printing include construction of complex 3D anatomic models for improved visual understanding, preoperative surgical planning, and surgical simulations for resident education. Intraoperatively, 3D printers have been successfully used in surgical guidance systems and in the creation of patient specific implantable devices. Furthermore, 3D printing is revolutionizing the field of regenerative medicine and tissue engineering, allowing construction of biocompatible scaffolds suitable for cell growth and vasculature. Advances in printing technology and evidence of positive clinical outcomes are needed before there is an expansion of 3D printing applied to the clinical setting.

  10. Synthesis and Characterization of Three Dimensional Nanostructures Based on Interconnected Carbon Nanomaterials

    Science.gov (United States)

    Koizumi, Ryota

    This thesis addresses various types of synthetic methods for novel three dimensional nanomaterials and nanostructures based on interconnected carbon nanomaterials using solution chemistry and chemical vapor deposition (CVD) methods. Carbon nanotube (CNT) spheres with porous and scaffold structures consisting of interconnected CNTs were synthesized by solution chemistry followed by freeze-drying, which have high elasticity under nano-indentation tests. This allows the CNT spheres to be potentially applied to mechanical dampers. CNTs were also grown on two dimensional materials--such as reduced graphene oxide (rGO) and hexagonal boron nitride (h-BN)--by CVD methods, which are chemically interconnected. CNTs on rGO and h-BN interconnected structures performed well as electrodes for supercapacitors. Furthermore, unique interconnected flake structures of alpha-phase molybdenum carbide were developed by a CVD method. The molybdenum carbide can be used for a catalyst of hydrogen evolution reaction activity as well as an electrode for supercapacitors.

  11. Structural Analysis of Three-dimensional Human Neural Tissue derived from Induced Pluripotent Stem Cells

    DEFF Research Database (Denmark)

    Terrence Brooks, Patrick; Rasmussen, Mikkel Aabech; Hyttel, Poul

    2016-01-01

    Objective: The present study aimed at establishing a method for production of a three-dimensional (3D) human neural tissue derived from induced pluripotent stem cells (iPSCs) and analyzing the outcome by a combination of tissue ultrastructure and expression of neural markers. Methods: A two......-step cell culture procedure was implemented by subjecting human iPSCs to a 3D scaffoldbased neural differentiation protocol. First, neural fate-inducing small molecules were used to create a neuroepithelial monolayer. Second, the monolayer was trypsinized into single cells and seeded into a porous...... polystyrene scaffold and further cultured to produce a 3D neural tissue. The neural tissue was characterized by a combination of immunohistochemistry and transmission electron microscopy (TEM). Results: iPSCs developed into a 3D neural tissue expressing markers for neural progenitor cells, early neural...

  12. Clinical Application of Three-Dimensional Printing Technology in Craniofacial Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Jong Woo Choi

    2015-05-01

    Full Text Available Three-dimensional (3D printing has been particularly widely adopted in medical fields. Application of the 3D printing technique has even been extended to bio-cell printing for 3D tissue/organ development, the creation of scaffolds for tissue engineering, and actual clinical application for various medical parts. Of various medical fields, craniofacial plastic surgery is one of areas that pioneered the use of the 3D printing concept. Rapid prototype technology was introduced in the 1990s to medicine via computer-aided design, computer-aided manufacturing. To investigate the current status of 3D printing technology and its clinical application, a systematic review of the literature was conducted. In addition, the benefits and possibilities of the clinical application of 3D printing in craniofacial surgery are reviewed, based on personal experiences with more than 500 craniofacial cases conducted using 3D printing tactile prototype models.

  13. Clinical Application of Three-Dimensional Printing Technology in Craniofacial Plastic Surgery

    Science.gov (United States)

    Kim, Namkug

    2015-01-01

    Three-dimensional (3D) printing has been particularly widely adopted in medical fields. Application of the 3D printing technique has even been extended to bio-cell printing for 3D tissue/organ development, the creation of scaffolds for tissue engineering, and actual clinical application for various medical parts. Of various medical fields, craniofacial plastic surgery is one of areas that pioneered the use of the 3D printing concept. Rapid prototype technology was introduced in the 1990s to medicine via computer-aided design, computer-aided manufacturing. To investigate the current status of 3D printing technology and its clinical application, a systematic review of the literature was conducted. In addition, the benefits and possibilities of the clinical application of 3D printing in craniofacial surgery are reviewed, based on personal experiences with more than 500 craniofacial cases conducted using 3D printing tactile prototype models. PMID:26015880

  14. Synthesis of three-dimensionally ordered macroporous manganese dioxide-carbon nanocomposites for supercapacitors

    Science.gov (United States)

    Liu, Zhi; Tan, Xiuli; Gao, Xin; Song, Lihong

    2014-12-01

    In this article, we report a composite of MnO2 nanoparticles supported by three-dimensionally ordered macroporous carbon (MnO2/3DOM carbon nanocomposites) fabricated by means of a simple multi-component infiltration of three-dimensional templates. MnO2 nanoparticles of 2 nm-6 nm are observed to be highly dispersed on the 3DOM carbon scaffolds. Cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy techniques are employed to assess the properties of these nanocomposites for use in supercapacitors. The results demonstrate that MnO2 can be effectively utilized with assistance of the 3DOM carbon in the electrode. The specific capacitance of the nanocomposite electrode can reach as high as 347 F g-1 at a current density of 0.5 A g-1. Moreover, the electrode exhibit excellent charge/discharge rate and good cycling stability, retaining over 92% of its initial charge after 5500 cycles at a current density of 2.5 A g-1. Such MnO2/3DOM carbon nanocomposite represents a promising exploring direction for enhancing the device performance of metal oxide-based electrochemical supercapacitors.

  15. Profiling stem cell states in three-dimensional biomaterial niches using high content image informatics.

    Science.gov (United States)

    Dhaliwal, Anandika; Brenner, Matthew; Wolujewicz, Paul; Zhang, Zheng; Mao, Yong; Batish, Mona; Kohn, Joachim; Moghe, Prabhas V

    2016-11-01

    materials relies on technologies that can sensitively discern cell response dynamics to biomaterials, while capturing cell-to-cell heterogeneity and preserving cellular native phenotypes. In this study, we illustrate the application of a novel high content image informatics platform to classify emergent human mesenchymal stem cell (hMSC) phenotypes in a diverse range of 3-D biomaterial scaffolds with high sensitivity and precision, and track cell responses to varied external stimuli. A major in silico innovation is the proposed image profiling technology based on unique three dimensional textural signatures of a mechanoreporter protein within the nuclei of stem cells cultured in 3-D scaffolds. This technology will accelerate the pace of high-fidelity biomaterial screening. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Distribution and viability of fetal and adult human bone marrow stromal cells in a biaxial rotating vessel bioreactor after seeding on polymeric 3D additive manufactured scaffolds

    NARCIS (Netherlands)

    Leferink, Anne Marijke; Chng, Yhee-Cheng; van Blitterswijk, Clemens; Moroni, Lorenzo

    2015-01-01

    One of the conventional approaches in tissue engineering is the use of scaffolds in combination with cells to obtain mechanically stable tissue constructs in vitro prior to implantation. Additive manufacturing by fused deposition modeling is a widely used technique to produce porous scaffolds with

  17. Fabrication, characterization, and in vitro evaluation of poly(lactic acid glycolic acid)/nano-hydroxyapatite composite microsphere-based scaffolds for bone tissue engineering in rotating bioreactors.

    Science.gov (United States)

    Lv, Qing; Nair, Lakshmi; Laurencin, Cato T

    2009-12-01

    Dynamic flow culture bioreactor systems have been shown to enhance in vitro bone tissue formation by facilitating mass transfer and providing mechanical stimulation. Our laboratory has developed a biodegradable poly (lactic acid glycolic acid) (PLAGA) mixed scaffold consisting of lighter-than-water (LTW) and heavier-than-water (HTW) microspheres as potential matrices for engineering tissue using a high aspect ratio vessel (HARV) rotating bioreactor system. We have demonstrated enhanced osteoblast differentiation and mineralization on PLAGA scaffolds in the HARV rotating bioreactor system when compared with static culture. The objective of the present study is to improve the mechanical properties and bioactivity of polymeric scaffolds by designing LTW polymer/ceramic composite scaffolds suitable for dynamic culture using a HARV bioreactor. We employed a microsphere sintering method to fabricate three-dimensional PLAGA/nano-hydroxyapatite (n-HA) mixed scaffolds composed of LTW and HTW composite microspheres. The mechanical properties, pore size and porosity of the composite scaffolds were controlled by varying parameters, such as sintering temperature, sintering time, and PLAGA/n-HA ratio. The PLAGA/n-HA (4:1) scaffold sintered at 90 degrees C for 3 h demonstrated the highest mechanical properties and an appropriate pore structure for bone tissue engineering applications. Furthermore, evaluation human mesenchymal stem cells (HMSCs) response to PLAGA/n-HA scaffolds was performed. HMSCs on PLAGA/n-HA scaffolds demonstrated enhanced proliferation, differentiation, and mineralization when compared with those on PLAGA scaffolds. Therefore, PLAGA/n-HA mixed scaffolds are promising candidates for HARV bioreactor-based bone tissue engineering applications. Copyright 2008 Wiley Periodicals, Inc.

  18. Informatics solutions for Three-dimensional visualization in real time

    International Nuclear Information System (INIS)

    Guzman Montoto, Jose Ignacio

    2002-01-01

    The advances reached in the development of the hardware and in the methods of acquisition of data like tomographic scanners and systems of analysis of images, have allowed obtaining geometric models of biomedical elements with the property of being manipulated through the three-dimensional visualization (3D). Nowadays, this visualization embraces from biological applications, including analysis of structures and its functional relationships, until medical applications that include anatomical accuracies and the planning or the training for complex surgical operations. This work proposes computer solutions to satisfy visualization requirements in real time. The developed algorithms are contained in a graphic library that will facilitate the development of future works. The obtained results allow facing current problems of three-dimensional representation of complex surfaces, realism is reached in the images and they have possible application in bioinformatics and medicine

  19. Visualization of traumatic tricuspid insufficiency by three-dimensional echocardiography.

    Science.gov (United States)

    Nishimura, Kazuhisa; Okayama, Hideki; Inoue, Katsuji; Saito, Makoto; Nagai, Takayuki; Suzuki, Jun; Ogimoto, Akiyoshi; Ohtsuka, Tomoaki; Higaki, Jitsuo

    2010-01-01

    A 19-year-old male was admitted to the emergency room of our hospital after a motor vehicle accident. During his first physical examination, a holosystolic murmur was heard at the fourth left parasternal border. Transthoracic echocardiography showed severe tricuspid insufficiency, but the cause of tricuspid insufficiency was unclear. Therefore, three-dimensional echocardiography was performed and demonstrated flail anterior, posterior and septal leaflets of the tricuspid valve. The diagnosis was tricuspid insufficiency due to papillary muscle rupture secondary to chest blunt trauma. Surgical repair of the tricuspid valve was performed in this patient. After surgery, the signs and symptoms of right ventricular heart failure were relieved. In this case, three-dimensional echocardiography was very useful for the evaluation of spatial destruction of the tricuspid valve and papillary muscle. 2009 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  20. Three-dimensional simulations of Nova capsule implosion experiments

    International Nuclear Information System (INIS)

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-01-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values

  1. Three-dimensional MR imaging of congenital heart disease

    International Nuclear Information System (INIS)

    Laschinger, J.C.; Vannier, M.W.; Knapp, R.H.; Gutierrez, F.R.; Cox, J.L.

    1987-01-01

    Contiguous 5-mm thick ECG-gated MR images of the thorax were edited using surface reconstruction techniques to produce three-dimensional (3D) images of the heart and great vessels in four healthy individuals and 25 patients with congenital heart disease (aged 3 months-30 years). Anomalies studied include atrial and ventricular septal defects, aortic coarctation, AV canal defects, double outlet ventricles, hypoplastic left heart syndrome, and a wide spectrum of patients with tetralogy of Fallot. The results were correlated with echocardiographic and cineradiographic studies, and with surgical findings or pathologic specimens. Three-dimensional reconstructions accurately localized the dimensions and locations of all cardiac and great vessel anomalies and often displayed anatomic findings not diagnosed or visualized with other forms of diagnostic imaging

  2. Secondary instability and transition in three-dimensional boundary layers

    Energy Technology Data Exchange (ETDEWEB)

    Stolte, A.; Bertolotti, F.P.; Koch, W. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik)

    1999-01-01

    Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)

  3. Secondary instability and transition in three-dimensional boundary layers

    Energy Technology Data Exchange (ETDEWEB)

    Stolte, A.; Bertolotti, F.P.; Koch, W. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik

    1999-12-01

    Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)

  4. Three-dimensional magnetotelluric axial anisotropic forward modeling and inversion

    Science.gov (United States)

    Cao, Hui; Wang, Kunpeng; Wang, Tao; Hua, Boguang

    2018-06-01

    Magnetotelluric (MT) data has been widely used to image underground electrical structural. However, when the significant axial resistivity anisotropy presents, how this influences three-dimensional MT data has not been resolved clearly yet. We here propose a scheme for three-dimensional modeling of MT data in presence of axial anisotropic resistivity, where the electromagnetic fields are decomposed into primary and secondary components. A 3D staggered-grid finite difference method is then used to resolve the resulting 3D governing equations. Numerical tests have completed to validate the correctness and accuracy of the present algorithm. A limited-memory Broyden-Fletcher-Goldfarb-Shanno method is then utilized to realize the 3D MT axial anisotropic inversion. The testing results show that, compared to the results of isotropic resistivity inversion, taking account the axial anisotropy can much improve the inverted results.

  5. Three-dimensional metallic opals fabricated by double templating

    International Nuclear Information System (INIS)

    Yan Qingfeng; Nukala, Pavan; Chiang, Yet-Ming; Wong, C.C.

    2009-01-01

    We report a simple and cost-effective double templating method for fabricating large-area three-dimensional metallic photonic crystals of controlled thickness. A self-assembled polystyrene opal was used as the first template to fabricate a silica inverse opal on a gold-coated glass substrate via sol-gel processing. Gold was subsequently infiltrated to the pores of the silica inverse opal using electrochemical deposition. A high-quality three-dimensional gold photonic crystal was obtained after removal of the secondary template (silica inverse opal). The effects of template sphere size and deposition current density on the gold growth rate, and the resulting morphology and growth mechanism of the gold opal, were investigated.

  6. Three-dimensional P velocity structure in Beijing area

    Science.gov (United States)

    Yu, Xiang-Wei; Chen, Yun-Tai; Wang, Pei-De

    2003-01-01

    A detail three-dimensional P wave velocity structure of Beijing, Tianjin and Tangshan area (BTT area) was determined by inverting local earthquake data. In total 16 048 P wave first arrival times from 16048 shallow and mid-depth crustal earthquakes, which occurred in and around the BTT area from 1992 to 1999 were used. The first arrival times are recorded by Northern China United Telemetry Seismic Network and Yanqing-Huailai Digital Seismic Network. Hypocentral parameters of 1 132 earthquakes with magnitude M L=1.7 6.2 and the three-dimensional P wave velocity structure were obtained simultaneously. The inversion result reveals the complicated lateral heterogeneity of P wave velocity structure around BTT area. The tomographic images obtained are also found to explain other seismological observations well.

  7. Quasi-three-dimensional particle imaging with digital holography.

    Science.gov (United States)

    Kemppinen, Osku; Heinson, Yuli; Berg, Matthew

    2017-05-01

    In this work, approximate three-dimensional structures of microparticles are generated with digital holography using an automated focus method. This is done by stacking a collection of silhouette-like images of a particle reconstructed from a single in-line hologram. The method enables estimation of the particle size in the longitudinal and transverse dimensions. Using the discrete dipole approximation, the method is tested computationally by simulating holograms for a variety of particles and attempting to reconstruct the known three-dimensional structure. It is found that poor longitudinal resolution strongly perturbs the reconstructed structure, yet the method does provide an approximate sense for the structure's longitudinal dimension. The method is then applied to laboratory measurements of holograms of single microparticles and their scattering patterns.

  8. Three-Dimensional Flow Behavior Inside the Submerged Entry Nozzle

    Science.gov (United States)

    Real-Ramirez, Cesar Augusto; Carvajal-Mariscal, Ignacio; Sanchez-Silva, Florencio; Cervantes-de-la-Torre, Francisco; Diaz-Montes, Jesus; Gonzalez-Trejo, Jesus

    2018-05-01

    According to various authors, the surface quality of steel depends on the dynamic conditions that occur within the continuous casting mold's upper region. The meniscus, found in that upper region, is where the solidification process begins. The liquid steel is distributed into the mold through a submerged entry nozzle (SEN). In this paper, the dynamic behavior inside the SEN is analyzed by means of physical experiments and numerical simulations. The particle imaging velocimetry technique was used to obtain the vector field in different planes and three-dimensional flow patterns inside the SEN volume. Moreover, large eddy simulation was performed, and the turbulence model results were used to understand the nonlinear flow pattern inside the SEN. Using scaled physical and numerical models, quasi-periodic behavior was observed due to the interaction of two three-dimensional vortices that move inside the SEN lower region located between the exit ports of the nozzle.

  9. Three-dimensional computerized tomography in mandibular condyle fractures

    International Nuclear Information System (INIS)

    Bermeo, Fausto; Salazar, Abad

    2003-01-01

    Now, car accidents are so commons, this associated to the high technology in produce automobiles make this type of accidents so serious and the consequences of mandibular condyle fractures are more commons and with more gravity, some of these patients, generally need a traqueostomy to be operated, that is why every second that we can save during the surgery is important. The normal exams as X rays and simple TAC give as an important idea but no complete, on the contrary the three-dimensional TAC permits to observe every damages and its exact location, this contribute to make a better surgery organization, the number and type of plates that we have to put and the better way to treat each case, that contribute to reduce time in operating theatre which is in benefit of the patient, diminishing risks in serious patients as they are, that is why we recommend the utilization of the three-dimensional TAC. (The author)

  10. Handwriting: three-dimensional kinetic synergies in circle drawing movements.

    Science.gov (United States)

    Hooke, Alexander W; Karol, Sohit; Park, Jaebum; Kim, Yoon Hyuk; Shim, Jae Kun

    2012-07-01

    The purpose of this study was to investigate central nervous system (CNS) strategies for controlling multifinger forces during a circle-drawing task. Subjects drew 30 concentric, discontinuous clockwise and counter clockwise circles, at self and experimenter-set paces. The three-dimensional trajectory of the pen's center of mass and the three-dimensional forces and moments of force at each contact between the hand and the pen were recorded. Uncontrolled Manifold Analysis was used to quantify the synergies between pen-hand contact forces in radial, tangential and vertical directions. Results showed that synergies in the radial and tangential components were significantly stronger than in the vertical component. Synergies in the clockwise direction were significantly stronger than the counterclockwise direction in the radial and vertical components. Pace was found to be insignificant under any condition.

  11. Three Dimensional Energy Transmitting Boundary in the Time Domain

    Directory of Open Access Journals (Sweden)

    Naohiro eNakamura

    2015-11-01

    Full Text Available Although the energy transmitting boundary is accurate and efficient for the FEM earthquake response analysis, it could be applied in the frequency domain only. In the previous papers, the author proposed an earthquake response analysis method using the time domain energy transmitting boundary for two dimensional problems. In this paper, this technique is expanded for three dimensional problems. The inner field is supposed to be a hexahedron shape and the approximate time domain boundary is explained, first. Next, two dimensional anti-plane time domain boundary is studied for a part of the approximate three dimensional boundary method. Then, accuracy and efficiency of the proposed method are confirmed by example problems.

  12. Canonical and symplectic analysis for three dimensional gravity without dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Escalante, Alberto, E-mail: aescalan@ifuap.buap.mx [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48 72570, Puebla, Pue. (Mexico); Osmart Ochoa-Gutiérrez, H. [Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Apartado postal 1152, 72001 Puebla, Pue. (Mexico)

    2017-03-15

    In this paper a detailed Hamiltonian analysis of three-dimensional gravity without dynamics proposed by V. Hussain is performed. We report the complete structure of the constraints and the Dirac brackets are explicitly computed. In addition, the Faddeev–Jackiw symplectic approach is developed; we report the complete set of Faddeev–Jackiw constraints and the generalized brackets, then we show that the Dirac and the generalized Faddeev–Jackiw brackets coincide to each other. Finally, the similarities and advantages between Faddeev–Jackiw and Dirac’s formalism are briefly discussed. - Highlights: • We report the symplectic analysis for three dimensional gravity without dynamics. • We report the Faddeev–Jackiw constraints. • A pure Dirac’s analysis is performed. • The complete structure of Dirac’s constraints is reported. • We show that symplectic and Dirac’s brackets coincide to each other.

  13. The thermoelectric performance of bulk three-dimensional graphene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhi, E-mail: yangzhi@tyut.edu.cn [Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024 (China); College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Lan, Guoqiang; Ouyang, Bin [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada); Xu, Li-Chun; Liu, Ruiping [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Xuguang, E-mail: liuxuguang@tyut.edu.cn [Key Lab of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Song, Jun [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada)

    2016-11-01

    The electronic and thermoelectric properties of a new carbon bulk material, three-dimensional (3D) graphene, are investigated in this study. Our results show that 3D graphene has unique electronic structure, i.e., near the Fermi level there exist Dirac cones. More importantly, the thermoelectric performance of 3D graphene is excellent, at room temperature the thermoelectric figure of merit (ZT) is 0.21, an order of magnitude higher than that of graphene. By introducing line defects, the ZT of 3D graphene could be enhanced to 1.52, indicating 3D graphene is a powerful candidate for constructing novel thermoelectric materials. - Highlights: • There exist Dirac cones in three-dimensional (3D) graphene. • The thermoelectric performance of 3D graphene is excellent. • The defective 3D graphene has better thermoelectric performance.

  14. Three-dimensional Modeling of Type Ia Supernova Explosions

    Science.gov (United States)

    Khokhlov, Alexei

    2001-06-01

    A deflagration explosion of a Type Ia Supernova (SNIa) is studied using three-dimensional, high-resolution, adaptive mesh refinement fluid dynamic calculations. Deflagration speed in an exploding Chandrasekhar-mass carbon-oxygen white dwarf (WD) grows exponentially, reaches approximately 30the speed of sound, and then declines due to a WD expansion. Outermost layers of the WD remain unburned. The explosion energy is comparable to that of a Type Ia supernova. The freezing of turbulent motions by expansion appears to be a crucial physical mechanism regulating the strength of a supernova explosion. In contrast to one-dimensional models, three-dimensional calculations predict the formation of Si-group elements and pockets of unburned CO in the middle and in central regions of a supernova ejecta. This, and the presence of unburned outer layer of carbon-oxygen may pose problems for SNIa spectra. Explosion sensitivity to initial conditions and its relation to a diversity of SNIa is discussed.

  15. SNAP-3D: a three-dimensional neutron diffusion code

    International Nuclear Information System (INIS)

    McCallien, C.W.J.

    1975-10-01

    A preliminary report is presented describing the data requirements of a one- two- or three-dimensional multi-group diffusion code, SNAP-3D. This code is primarily intended for neutron diffusion calculations but it can also carry out gamma calculations if the diffuse approximation is accurate enough. It is suitable for fast and thermal reactor core calculations and for shield calculations. It is assumed the reader is familiar with the older, two-dimensional code SNAP and can refer to the report [TRG-Report-1990], describing it. The present report concentrates on the enhancements to SNAP that have been made to produce the three-dimensional version, SNAP-3D, and is intended to act a a guide on data preparation until a single, comprehensive report can be published. (author)

  16. Analytical Prediction of Three Dimensional Chatter Stability in Milling

    Science.gov (United States)

    Altintas, Yusuf

    The chip regeneration mechanism during chatter is influenced by vibrations in three directions when milling cutters with ball end, bull nose, or inclined cutting edges are used. A three dimensional chatter stability is modeled analytically in this article. The dynamic milling system is formulated as a function of cutter geometry, the frequency response of the machine tool structure at the cutting zone in three Cartesian directions, cutter engagement conditions and material property. The dynamic milling system with nonlinearities and periodic delayed differential equations is reduced to a three dimensional linear stability problem by approximations based on the physics of milling. The chatter stability lobes are predicted in the frequency domain using the proposed analytical solution, and verified experimentally in milling a Titanium alloy with a face milling cutter having circular inserts.

  17. Pattern formation and three-dimensional instability in rotating flows

    Science.gov (United States)

    Christensen, Erik A.; Aubry, Nadine; Sorensen, Jens N.

    1997-03-01

    A fluid flow enclosed in a cylindrical container where fluid motion is created by the rotation of one end wall as a centrifugal fan is studied. Direct numerical simulations and spatio-temporal analysis have been performed in the early transition scenario, which includes a steady-unsteady transition and a breakdown of axisymmetric to three-dimensional flow behavior. In the early unsteady regime of the flow, the central vortex undergoes a vertical beating motion, accompanied by axisymmetric spikes formation on the edge of the breakdown bubble. As traveling waves, the spikes move along the central vortex core toward the rotating end-wall. As the Reynolds number is increased further, the flow undergoes a three-dimensional instability. The influence of the latter on the previous patterns is studied.

  18. Three-dimensional theory for light-matter interaction

    DEFF Research Database (Denmark)

    Sørensen, Martin Westring; Sørensen, Anders Søndberg

    2008-01-01

    We present a full quantum mechanical three dimensional theory describing an electromagnetic field interacting with an ensemble of identical atoms. The theory is constructed such that it describes recent experiments on light-matter quantum interfaces, where the quantum fluctuations of light...... to a dressed state picture, where the light modes are solutions to the diffraction problem, and develop a perturbative expansion in the fluctuations. The fluctuations are due to quantum fluctuations as well as the random positions of the atoms. In this perturbative expansion we show how the quantum...... fluctuations are mapped between atoms and light while the random positioning of the atoms give rise to decay due to spontaneous emission. Furthermore we identify limits, where the full three dimensional theory reduce to the one dimensional theory typically used to describe the interaction....

  19. Three-dimensional imaging technology offers promise in medicine.

    Science.gov (United States)

    Karako, Kenji; Wu, Qiong; Gao, Jianjun

    2014-04-01

    Medical imaging plays an increasingly important role in the diagnosis and treatment of disease. Currently, medical equipment mainly has two-dimensional (2D) imaging systems. Although this conventional imaging largely satisfies clinical requirements, it cannot depict pathologic changes in 3 dimensions. The development of three-dimensional (3D) imaging technology has encouraged advances in medical imaging. Three-dimensional imaging technology offers doctors much more information on a pathology than 2D imaging, thus significantly improving diagnostic capability and the quality of treatment. Moreover, the combination of 3D imaging with augmented reality significantly improves surgical navigation process. The advantages of 3D imaging technology have made it an important component of technological progress in the field of medical imaging.

  20. Design of three-dimensional nonimaging concentrators with inhomogeneous media

    Science.gov (United States)

    Minano, J. C.

    1986-09-01

    A three-dimensional nonimaging concentrator is an optical system that transforms a given four-parametric manifold of rays reaching a surface (entry aperture) into another four-parametric manifold of rays reaching the receiver. A procedure of design of such concentrators is developed. In general, the concentrators use mirrors and inhomogeneous media (i.e., gradient-index media). The concentrator has the maximum concentration allowed by the theorem of conservation of phase-space volume. This is the first known concentrator with such properties. The Welford-Winston edge-ray principle in three-di