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Sample records for fabricate 3d alginate

  1. 3D Cell Culture in Alginate Hydrogels

    PubMed Central

    Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael

    2015-01-01

    This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue. PMID:27600217

  2. Controllable 3D alginate hydrogel patterning via visible-light induced electrodeposition.

    PubMed

    Dai, Gaole; Wan, Wenfeng; Zhao, Yuliang; Wang, Zixun; Li, Wenjun; Shi, Peng; Shen, Yajing

    2016-01-01

    The fabrication of alginate hydrogel in 3D has recently received increasing attention owing to its distinct efficacy as biocompatible scaffold for 3D cell culture, biomedical and tissue engineering. We report a controllable 3D alginate hydrogel patterning method by developing a visible-light induced electrodeposition chip. The chip mainly consists of a photoconductive titanyl phthalocyanine (TiOPc) anode plate, an indium tin oxide (ITO) cathode plate and the mixed solution (1% sodium alginate and 0.25% CaCO3 nano particles) between them. After a designed visible-light pattern is projected onto the TiOPc plate, the produced H(+) by electrolysis will trigger Ca(2+) near the anode (illuminated area), and then the gelation of calcium alginate patterns, as desired, happens controllably. In addition, we further establish an exponential model to elucidate the gel growth v.s. time and current density. The results indicate that the proposed method is able to fabricate various 3D alginate hydrogel patterns in a well controllable manner, and maintain the laden cells at high survival rate (>98% right after gel formation). This research paves an alternative way for 3D alginate hydrogel patterning with high controllability and productivity, which would benefit the research in biomedical and tissue engineering. PMID:27108617

  3. 3D Printing Facilitated Scaffold-free Tissue Unit Fabrication

    PubMed Central

    Tan, Yu; Richards, Dylan J.; Trusk, Thomas C.; Visconti, Richard P.; Yost, Michael J.; Kindy, Mark S.; Drake, Christopher J.; Argraves, William Scott; Markwald, Roger R.; Mei, Ying

    2014-01-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing micro-droplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit micro-droplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation. PMID:24717646

  4. 3D printing facilitated scaffold-free tissue unit fabrication.

    PubMed

    Tan, Yu; Richards, Dylan J; Trusk, Thomas C; Visconti, Richard P; Yost, Michael J; Kindy, Mark S; Drake, Christopher J; Argraves, William Scott; Markwald, Roger R; Mei, Ying

    2014-06-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing microdroplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit microdroplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation. PMID:24717646

  5. 3D bioprinting of heterogeneous aortic valve conduits with alginate/gelatin hydrogels.

    PubMed

    Duan, Bin; Hockaday, Laura A; Kang, Kevin H; Butcher, Jonathan T

    2013-05-01

    Heart valve disease is a serious and growing public health problem for which prosthetic replacement is most commonly indicated. Current prosthetic devices are inadequate for younger adults and growing children. Tissue engineered living aortic valve conduits have potential for remodeling, regeneration, and growth, but fabricating natural anatomical complexity with cellular heterogeneity remain challenging. In the current study, we implement 3D bioprinting to fabricate living alginate/gelatin hydrogel valve conduits with anatomical architecture and direct incorporation of dual cell types in a regionally constrained manner. Encapsulated aortic root sinus smooth muscle cells (SMC) and aortic valve leaflet interstitial cells (VIC) were viable within alginate/gelatin hydrogel discs over 7 days in culture. Acellular 3D printed hydrogels exhibited reduced modulus, ultimate strength, and peak strain reducing slightly over 7-day culture, while the tensile biomechanics of cell-laden hydrogels were maintained. Aortic valve conduits were successfully bioprinted with direct encapsulation of SMC in the valve root and VIC in the leaflets. Both cell types were viable (81.4 ± 3.4% for SMC and 83.2 ± 4.0% for VIC) within 3D printed tissues. Encapsulated SMC expressed elevated alpha-smooth muscle actin, while VIC expressed elevated vimentin. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting. PMID:23015540

  6. Surface modified alginate microcapsules for 3D cell culture

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

    2016-06-01

    Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

  7. Fabrication of 3D Silicon Sensors

    SciTech Connect

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; Kenney, C.; Hasi, J.; Da Via, C.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  8. Freeform drop-on-demand laser printing of 3D alginate and cellular constructs.

    PubMed

    Xiong, Ruitong; Zhang, Zhengyi; Chai, Wenxuan; Huang, Yong; Chrisey, Douglas B

    2015-12-01

    Laser printing is an orifice-free printing approach and has been investigated for the printing of two-dimensional patterns and simple three-dimensional (3D) constructs. To demonstrate the potential of laser printing as an effective bioprinting technique, both straight and Y-shaped tubes have been freeform printed using two different bioinks: 8% alginate solution and 2% alginate-based mouse fibroblast suspension. It has been demonstrated that 3D cellular tubes, including constructs with bifurcated overhang structures, can be adequately fabricated under optimal printing conditions. The post-printing cell viabilities immediately after printing as well as after 24 h incubation are above 60% for printed straight and Y-shaped fibroblast tubes. During fabrication, overhang and spanning structures can be printed using a dual-purpose crosslinking solution, which also functions as a support material. The advancement distance of gelation reaction front after a cycle time of the receiving platform downward motion should be estimated for experimental planning. The optimal downward movement step size of receiving platform should be chosen to be equal to the height of ungelled portion of a previously printed layer. PMID:26693735

  9. Rapid 3D Printing of Multifunctional Calcium Alginate Gel Pipes using Coaxial Jet Extruder

    NASA Astrophysics Data System (ADS)

    Rykaczewski, Konrad; Damle, Viraj

    2014-11-01

    Calcium alginate (CA) forms when solution containing sodium alginate (SA) comes in contact with a CaCl2 solution. The resulting gel is biocompatible as well as edible and is used in production of bio-scaffolds, artificial plant seeds, and edible substances. In the latter application, referred to in the culinary world as ``spherification,'' flavored liquids are mixed with the SA and dripped into CaCl2 solution to form gel encapsulated flavored ``marbles.'' Previously, crude 3D printing of CA structures has been achieved by stacking of such flavored liquid filled marbles. In turn, solid CA rods have been fabricated by properly mixing flow of the two solutions using a microfluidic device. Here we show that by using two circular cross-section coaxial nozzles to produce coaxial jets of the SA and CaCl2 solutions, liquid filled CA micro-to-mili scale gel pipes can be produced at speeds around ~ 150 mm/s. Such extrusion rate is compatible with most commercially available 3D printers, facilitating adoption of the CA pipe coaxial jet extruder. Here, the impact of inner and outer liquid properties and flow speeds on the gel pipe extrusion process is discussed. KR acknowledges startup funding from ASU.

  10. Fabricating 3D figurines with personalized faces.

    PubMed

    Tena, J Rafael; Mahler, Moshe; Beeler, Thabo; Grosse, Max; Hengchin Yeh; Matthews, Iain

    2013-01-01

    We present a semi-automated system for fabricating figurines with faces that are personalised to the individual likeness of the customer. The efficacy of the system has been demonstrated by commercial deployments at Walt Disney World Resort and Star Wars Celebration VI in Orlando Florida. Although the system is semi automated, human intervention is limited to a few simple tasks to maintain the high throughput and consistent quality required for commercial application. In contrast to existing systems that fabricate custom heads that are assembled to pre-fabricated plastic bodies, our system seamlessly integrates 3D facial data with a predefined figurine body into a unique and continuous object that is fabricated as a single piece. The combination of state-of-the-art 3D capture, modelling, and printing that are the core of our system provide the flexibility to fabricate figurines whose complexity is only limited by the creativity of the designer. PMID:24808129

  11. Microfluidic Generation of Monodisperse, Structurally Homogeneous Alginate Microgels for Cell Encapsulation and 3D Cell Culture.

    PubMed

    Utech, Stefanie; Prodanovic, Radivoje; Mao, Angelo S; Ostafe, Raluca; Mooney, David J; Weitz, David A

    2015-08-01

    Monodisperse alginate microgels (10-50 μm) are created via droplet-based microfluidics by a novel crosslinking procedure. Ionic crosslinking of alginate is induced by release of chelated calcium ions. The process separates droplet formation and gelation reaction enabling excellent control over size and homogeneity under mild reaction conditions. Living mesenchymal stem cells are encapsulated and cultured in the generated 3D microenvironments. PMID:26039892

  12. Fluid and cell behaviors along a 3D printed alginate/gelatin/fibrin channel.

    PubMed

    Xu, Yufan; Wang, Xiaohong

    2015-08-01

    Three-dimensional (3D) cell manipulation is available with the integration of microfluidic technology and rapid prototyping techniques. High-Fidelity (Hi-Fi) constructs hold enormous therapeutic potential for organ manufacturing and regenerative medicine. In the present paper we introduced a quasi-three-dimensional (Q3D) model with parallel biocompatible alginate/gelatin/fibrin hurdles. The behaviors of fluids and cells along the microfluidic channels with various widths were studied. Cells inside the newly designed microfluidic channels attached and grew well. Morphological changes of adipose-derived stem cells (ADSCs) in both two-dimensional (2D) and 3D milieu were found on the printed constructs. Endothelialization occurred with the co-cultures of ADSCs and hepatocytes. This study provides insights into the interactions among fluids, cells and biomaterials, the behaviors of fluids and cells along the microfluidic channels, and the applications of Q3D techniques. PMID:25727058

  13. 3D Bioprinting Human Chondrocytes with Nanocellulose-Alginate Bioink for Cartilage Tissue Engineering Applications.

    PubMed

    Markstedt, Kajsa; Mantas, Athanasios; Tournier, Ivan; Martínez Ávila, Héctor; Hägg, Daniel; Gatenholm, Paul

    2015-05-11

    The introduction of 3D bioprinting is expected to revolutionize the field of tissue engineering and regenerative medicine. The 3D bioprinter is able to dispense materials while moving in X, Y, and Z directions, which enables the engineering of complex structures from the bottom up. In this study, a bioink that combines the outstanding shear thinning properties of nanofibrillated cellulose (NFC) with the fast cross-linking ability of alginate was formulated for the 3D bioprinting of living soft tissue with cells. Printability was evaluated with concern to printer parameters and shape fidelity. The shear thinning behavior of the tested bioinks enabled printing of both 2D gridlike structures as well as 3D constructs. Furthermore, anatomically shaped cartilage structures, such as a human ear and sheep meniscus, were 3D printed using MRI and CT images as blueprints. Human chondrocytes bioprinted in the noncytotoxic, nanocellulose-based bioink exhibited a cell viability of 73% and 86% after 1 and 7 days of 3D culture, respectively. On the basis of these results, we can conclude that the nanocellulose-based bioink is a suitable hydrogel for 3D bioprinting with living cells. This study demonstrates the potential use of nanocellulose for 3D bioprinting of living tissues and organs. PMID:25806996

  14. Optofluidic fabrication for 3D-shaped particles.

    PubMed

    Paulsen, Kevin S; Di Carlo, Dino; Chung, Aram J

    2015-01-01

    Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated. PMID:25904062

  15. Optofluidic fabrication for 3D-shaped particles

    NASA Astrophysics Data System (ADS)

    Paulsen, Kevin S.; di Carlo, Dino; Chung, Aram J.

    2015-04-01

    Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated.

  16. 3D nanostructures fabricated by advanced stencil lithography.

    PubMed

    Yesilkoy, F; Flauraud, V; Rüegg, M; Kim, B J; Brugger, J

    2016-03-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au. PMID:26884085

  17. 3D nanostructures fabricated by advanced stencil lithography

    NASA Astrophysics Data System (ADS)

    Yesilkoy, F.; Flauraud, V.; Rüegg, M.; Kim, B. J.; Brugger, J.

    2016-02-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au.

  18. Laser-assisted fabrication of highly viscous alginate microsphere

    NASA Astrophysics Data System (ADS)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  19. Vertical Flow Lithography for Fabrication of 3D Anisotropic Particles.

    PubMed

    Habasaki, Shohei; Lee, Won Chul; Yoshida, Shotaro; Takeuchi, Shoji

    2015-12-22

    A microfluidics-based method for the 3D fabrication of anisotropic particles is reported. The method uses a vertical microchannel where tunable light patterns solidify photocurable resins for stacking multiple layers of the resins, thus enabling an application of stereolithography concepts to conventional flow lithography. Multilayered, tapered, and angular compartmental microparticles are demonstrated. PMID:26551590

  20. Spontaneous gene transfection of human bone cells using 3D mineralized alginate-chitosan macrocapsules.

    PubMed

    Green, David W; Kim, Eun-Jung; Jung, Han-Sung

    2015-09-01

    The effectiveness of nonviral gene therapy remains uncertain because of low transfection efficiencies and high toxicities compared with viral-based strategies. We describe a simple system for transient transfection of continuous human cell lines, with low toxicity, using mineral-coated chitosan and alginate capsules. As proof-of-concept, we demonstrate transfection of Saos-2 and MG63 human osteosarcoma continuous cell lines with gfp, LacZ reporter genes, and a Sox-9 carrying plasmid, to illustrate expression of a functional gene with therapeutic relevance. We show that continuous cell lines transfect with significant efficiency of up to 65% possibly through the interplay between chitosan and DNA complexation and calcium/phosphate-induced translocation into cells entrapped within the 3D polysaccharide based environment, as evidenced by an absence of transfection in unmineralized and chitosan-free capsules. We demonstrated that our transfection system was equally effective at transfection of primary human bone marrow stromal cells. To illustrate, the Sox-9, DNA plasmid was spontaneously expressed in primary human bone marrow stromal cells at 7 days with up to 90% efficiency in two repeats. Mineralized polysaccharide macrocapsules are gene delivery vehicles with a number of biological and practical advantages. They are highly efficient at self-transfecting primary bone cells, with programmable spatial and temporal delivery prospects, premineralized bone-like environments, and have no cytotoxic effects, as compared with many other nonviral systems. PMID:25645372

  1. Formulation and stability evaluation of 3D alginate beads potentially useful for cumulus-oocyte complexes culture.

    PubMed

    Dorati, Rossella; Genta, Ida; Ferrari, Michela; Vigone, Giulia; Merico, Valeria; Garagna, Silvia; Zuccotti, Maurizio; Conti, Bice

    2016-01-01

    Ovarian follicle encapsulation in synthetic or natural matrixes based on biopolymers is potentially a promising approach to in vitro maturation (IVM) process, since it maintains follicle 3D organisation by preventing its flattening and consequent disruption of gap junctions, preserving the functional relationship between oocyte and companion follicle cells. The aim of the work was to optimise physico-chemical parameters of alginate microcapsules for perspective IVM under 3D environments. On this purpose alginate and cross-linking agent concentrations were investigated. Alginate concentration between 0.75% and 0.125% w/w and Mg(2+), Ba(2+), Ca(2+ )at concentration between 100 and 20 mM were tested. Follicle encapsulation was obtained by on purpose modified diffusion setting gelation technique, and evaluated together with beads, chemical and mechanical stability in standard and stressing conditions. Beads permeability was tested towards albumin, fetuin, pyruvate, glucose, pullulan. Results demonstrated that 0.25% alginate cross-linked in 100 mM CaCl2 beads is suitable to follicle encapsulation. PMID:26791322

  2. 3D printing of liquid metals as fugitive inks for fabrication of 3D microfluidic channels.

    PubMed

    Parekh, Dishit P; Ladd, Collin; Panich, Lazar; Moussa, Khalil; Dickey, Michael D

    2016-05-21

    This paper demonstrates a simple method to fabricate 3D microchannels and microvasculature at room temperature by direct-writing liquid metal as a sacrificial template. The formation of a surface oxide skin on the low-viscosity liquid metal stabilizes the shape of the printed metal for planar and out-of-plane structures. The printed structures can be embedded in a variety of soft (e.g. elastomeric) and rigid (e.g. thermoset) polymers. Both acid and electrochemical reduction are capable of removing the oxide skin that forms on the metal, which destabilizes the ink so that it withdraws from the encapsulating material due to capillary forces, resulting in nearly full recovery of the fugitive ink at room temperature. Whereas conventional fabrication procedures typically confine microchannels to 2D planes, the geometry of the printed microchannels can be varied from a simple 2D network to complex 3D architectures without using lithography. The method produces robust monolithic structures without the need for any bonding or assembling techniques that often limit the materials of construction of conventional microchannels. Removing select portions of the metal leaves behind 3D metal features that can be used as antennas, interconnects, or electrodes for interfacing with lab-on-a-chip devices. This paper describes the capabilities and limitations of this simple process. PMID:27025537

  3. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    PubMed Central

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  4. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    NASA Astrophysics Data System (ADS)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-06-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  5. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    PubMed

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  6. Fabrication of novel core-shell hybrid alginate hydrogel beads.

    PubMed

    Liu, Hongxia; Wang, Chaoyang; Gao, Quanxing; Liu, Xinxing; Tong, Zhen

    2008-03-01

    Novel hybrid alginate hydrogel beads with shells of porous CaCO3 microparticles were fabricated by templating water-in-oil emulsion and subsequent in situ gelation. Porous CaCO3 microparticles were self-assembled at interfaces of water-in-oil emulsion. Water droplets containing alginate in the emulsion were subsequently in situ gelated by Ca2+ released from CaCO3 through decreasing pH with slow hydrolysis of d-glucono-delta-lactone (GDL). The resulting hybrid beads with alginate gel cores and shells of porous CaCO3 microparticles were called colloidosomes. The packed density of CaCO3 microparticles in the shell increased with increasing the ratio of the CaCO3 microparticle weight to the water phase volume Mp/Vw and decreased with addition of NaCl into water. The size of the produced colloidosome beads was independent of Mp/Vw. Increasing the volume fraction of water Phi w to 0.5, some colloidosome beads deformed to nonspheral shape and even broken. Brilliant blue (BB) as a drug model was loaded into the colloidosome beads by being dissolved in the alginate aqueous solution before gelation. The BB release from the colloidosome beads was slowed down because of the formation of the shells of CaCO3 microparticles. The colloidosome beads may find applications as delivery vehicles for drugs, cosmetics, food supplements and living cell. PMID:17964745

  7. Micro stereo lithography and fabrication of 3D microdevices

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1999-08-01

    Micro Stereo Lithography (MSL) is a poor man's LIGA for fabricating high aspect ratio MEMS devices in UV curable semiconducting polymers using either two computer-controlled low inertia galvanometric mirrors with the aid of focusing lens or an array of optical fibers. For 3D MEMS devices, the polymers need to have conductive and possibly piezoelectric or ferroelectric properties. Such polymers are being developed at Penn State resulting in microdevices for fluid and drug delivery. Applications may include implanted medical delivery systems, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components. With the invention of organic thin film transistor, now it is possible to fabricate 3D polymeric MEMS devices with built-in-electronics similar to silicon based microelectronics. In this paper, a brief introduction of MSL system is presented followed by a detailed design and development of micro pumps using this approach.

  8. A method to fabricate disconnected silver nanostructures in 3D.

    PubMed

    Vora, Kevin; Kang, SeungYeon; Mazur, Eric

    2012-01-01

    The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.(1,2) Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.(3-7) However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.(8) Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,(9) such as coupled metal dot(10,11)or coupled metal rod(12,13) resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses. In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can

  9. Fabrication of cationic chitin nanofiber/alginate composite materials.

    PubMed

    Sato, Koki; Tanaka, Kohei; Takata, Yusei; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

    2016-10-01

    We have already found that an amidinated chitin, which was prepared by the reaction of a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, was converted into an amidinium chitin bicarbonate with nanofiber morphology by CO2 gas bubbling and ultrasonic treatments in water. In this study, we performed the fabrication of composite materials of such cationic chitin nanofibers with an anionic polysaccharide, sodium alginate, by ion exchange. When the amidinium chitin bicarbonate nanofiber aqueous dispersion was added to an aqueous solution of sodium alginate, the composite material was agglomerated, which was isolated by centrifugation, filtration, and lyophilization, to form a manipulatable sheet. The morphology of the resulting sheet at nano-scale was evaluated by SEM measurement. PMID:27288700

  10. 3D ultrasound imaging for prosthesis fabrication and diagnostic imaging

    SciTech Connect

    Morimoto, A.K.; Bow, W.J.; Strong, D.S.

    1995-06-01

    The fabrication of a prosthetic socket for a below-the-knee amputee requires knowledge of the underlying bone structure in order to provide pressure relief for sensitive areas and support for load bearing areas. The goal is to enable the residual limb to bear pressure with greater ease and utility. Conventional methods of prosthesis fabrication are based on limited knowledge about the patient`s underlying bone structure. A 3D ultrasound imaging system was developed at Sandia National Laboratories. The imaging system provides information about the location of the bones in the residual limb along with the shape of the skin surface. Computer assisted design (CAD) software can use this data to design prosthetic sockets for amputees. Ultrasound was selected as the imaging modality. A computer model was developed to analyze the effect of the various scanning parameters and to assist in the design of the overall system. The 3D ultrasound imaging system combines off-the-shelf technology for image capturing, custom hardware, and control and image processing software to generate two types of image data -- volumetric and planar. Both volumetric and planar images reveal definition of skin and bone geometry with planar images providing details on muscle fascial planes, muscle/fat interfaces, and blood vessel definition. The 3D ultrasound imaging system was tested on 9 unilateral below-the- knee amputees. Image data was acquired from both the sound limb and the residual limb. The imaging system was operated in both volumetric and planar formats. An x-ray CT (Computed Tomography) scan was performed on each amputee for comparison. Results of the test indicate beneficial use of ultrasound to generate databases for fabrication of prostheses at a lower cost and with better initial fit as compared to manually fabricated prostheses.

  11. Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication

    PubMed Central

    Morgan, Alex J. L.; Hidalgo San Jose, Lorena; Jamieson, William D.; Wymant, Jennifer M.; Song, Bing; Stephens, Phil

    2016-01-01

    The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components. PMID:27050661

  12. Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication.

    PubMed

    Morgan, Alex J L; Hidalgo San Jose, Lorena; Jamieson, William D; Wymant, Jennifer M; Song, Bing; Stephens, Phil; Barrow, David A; Castell, Oliver K

    2016-01-01

    The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components. PMID:27050661

  13. Solid organ fabrication: comparison of decellularization to 3D bioprinting.

    PubMed

    Jung, Jangwook P; Bhuiyan, Didarul B; Ogle, Brenda M

    2016-01-01

    Solid organ fabrication is an ultimate goal of Regenerative Medicine. Since the introduction of Tissue Engineering in 1993, functional biomaterials, stem cells, tunable microenvironments, and high-resolution imaging technologies have significantly advanced efforts to regenerate in vitro culture or tissue platforms. Relatively simple flat or tubular organs are already in (pre)clinical trials and a few commercial products are in market. The road to more complex, high demand, solid organs including heart, kidney and lung will require substantive technical advancement. Here, we consider two emerging technologies for solid organ fabrication. One is decellularization of cadaveric organs followed by repopulation with terminally differentiated or progenitor cells. The other is 3D bioprinting to deposit cell-laden bio-inks to attain complex tissue architecture. We reviewed the development and evolution of the two technologies and evaluated relative strengths needed to produce solid organs, with special emphasis on the heart and other tissues of the cardiovascular system. PMID:27583168

  14. Biomedical-grade, high mannuronic acid content (BioMVM) alginate enhances the proteoglycan production of primary human meniscal fibrochondrocytes in a 3-D microenvironment

    PubMed Central

    Rey-Rico, Ana; Klich, Angelique; Cucchiarini, Magali; Madry, Henning

    2016-01-01

    Alginates are important hydrogels for meniscus tissue engineering as they support the meniscal fibrochondrocyte phenotype and proteoglycan production, the extracellular matrix (ECM) component chiefly responsible for its viscoelastic properties. Here, we systematically evaluated four biomedical- and two nonbiomedical-grade alginates for their capacity to provide the best three-dimensional (3-D) microenvironment and to support proteoglycan synthesis of encapsulated human meniscal fibrochondrocytes in vitro. Biomedical-grade, high mannuronic acid alginate spheres (BioLVM, BioMVM) were the most uniform in size, indicating an effect of the purity of alginate on the shape of the spheres. Interestingly, the purity of alginates did not affect cell viability. Of note, only fibrochondrocytes encapsulated in BioMVM alginate produced and retained significant amounts of proteoglycans. Following transplantation in an explant culture model, the alginate spheres containing fibrochondrocytes remained in close proximity with the meniscal tissue adjacent to the defect. The results reveal a promising role of BioMVM alginate to enhance the proteoglycan production of primary human meniscal fibrochondrocytes in a 3-D hydrogel microenvironment. These findings have significant implications for cell-based translational studies aiming at restoring lost meniscal tissue in regions containing high amounts of proteoglycans. PMID:27302206

  15. Peptide-incorporated 3D porous alginate scaffolds with enhanced osteogenesis for bone tissue engineering.

    PubMed

    Luo, Zuyuan; Yang, Yue; Deng, Yi; Sun, Yuhua; Yang, Hongtao; Wei, Shicheng

    2016-07-01

    Good bioactivity and osteogenesis of three-dimensional porous alginate scaffolds (PAS) are critical for bone tissue engineering. In this work, alginate and bone-forming peptide-1 (BFP-1), derived from bone morphogenetic protein-7 (BMP-7), have been combined together (without carbodiimide chemistry treatment) to develop peptide-incorporated PAS (p-PAS) for promoting bone repairing ability. The mechanical properties and SEM images show no difference between pure PAS and p-PAS. The release kinetics of the labeled peptide with 6-carboxy tetramethyl rhodamine from the PAS matrix suggests that the peptide is released in a relatively sustained manner. In the cell experiment, p-PAS show higher cell adhesion, spreading, proliferation and alkaline phosphatase (ALP) activity than the pristine PAS group, indicating that the BFP-1 released from p-PAS could significantly promote the aggregation and differentiation of osteoblasts, especially at 10μg/mL of trapped peptide concentration (p-PAS-10). Furthermore, p-PAS-10 was implanted into Beagle calvarial defects and bone regeneration was analyzed after 4 weeks. New bone formation was assessed by calcein and Masson's trichrome staining. The data reveal that p-PAS group exhibits significantly enhanced oseto-regenerative capability in vivo. The peptide-modified PAS with promoted bioactivity and osteogenic differentiation in vitro as well as bone formation ability in vivo could be promising tissue engineering materials for repairing and regeneration of bone defects. PMID:27022863

  16. Proliferation and enrichment of CD133+ glioblastoma cancer stem cells on 3D chitosan-alginate scaffolds

    PubMed Central

    Kievit, Forrest M.; Florczyk, Stephen J.; Leung, Matthew C.; Wang, Kui; Wu, Jennifer D.; Silber, John R.; Ellenbogen, Richard G.; Lee, Jerry S.H.; Zhang, Miqin

    2014-01-01

    Emerging evidence implicates cancer stem cells (CSCs) as primary determinants of the clinical behavior of human cancers, representing an ideal target for next-generation anticancer therapies. However CSCs are difficult to propagate in vitro, severely limiting the study of CSC biology and drug development. Here we report that growing cells from glioblastoma (GBM) cell lines on three dimensional (3D) porous chitosan-alginate (CA) scaffolds dramatically promotes the proliferation and enrichment of cells possessing the hallmarks of CSCs. CA scaffold-grown cells were found more tumorigenic in nude mouse xenografts than cells grown from monolayers. Growing in CA scaffolds rapidly promoted expression of genes involved in the epithelial-to-mesenchymal transition that has been implicated in the genesis of CSCs. Our results indicate that CA scaffolds have utility as a simple and inexpensive means to cultivate CSCs in vitro in support of studies to understand CSC biology and develop more effective anti-cancer therapies. PMID:25109438

  17. Fabrication of inorganic hydroxyapatite nanoparticles and organic biomolecules-dual encapsulated alginate microspheres.

    PubMed

    Wang, Yu-Pu; Liao, Yu-Te; Liu, Chia-Hung; Yu, Jiashing; Chen, Jung-Chih; Wu, Kevin C-W

    2015-01-01

    Inorganic hydroxyapatite nanoparticles (HANPs) and two kinds of organic biomolecules (i.e., fluorescent dye rhodamine 6G and protein lysozyme) were coencapsulated into alginate microspheres through an air dynamical atomization with optimized operation conditions. The synthesized microspheres have several advantages: HANP provides osteoconductivity and mechanical strength, rhodamine 6G (R6G) and lysozyme act as model drugs, and alginate provides excellent biocompatibility and carboxylate functionality. The results of fluorescent microscopic images indicated the successful dual encapsulation of HANPs and lysozyme inside the alginate microspheres. Furthermore, the results of 3- (4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay showed that the fabricated alginate microspheres could be uptaken by HepG2 without apparent cytotoxicity. The dual encapsulated alginate microspheres fabricated in this study show great potential in many biomedical applications. PMID:25939572

  18. Cell-secreted extracellular matrix formation and differentiation of adipose-derived stem cells in 3D alginate scaffolds with tunable properties.

    PubMed

    Guneta, Vipra; Loh, Qiu Li; Choong, Cleo

    2016-05-01

    Three dimensional (3D) alginate scaffolds with tunable mechanical and structural properties are explored for investigating the effect of the scaffold properties on stem cell behavior and extracellular matrix (ECM) formation. Varying concentrations of crosslinker (20 - 60%) are used to tune the stiffness, porosity, and the pore sizes of the scaffolds post-fabrication. Enhanced cell proliferation and adipogenesis occur in scaffolds with 3.52 ± 0.59 kPa stiffness, 87.54 ± 18.33% porosity and 68.33 ± 0.88 μm pore size. On the other hand, cells in scaffolds with stiffness greater than 11.61 ± 1.74 kPa, porosity less than 71.98 ± 6.25%, and pore size less than 64.15 ± 4.34 μm preferentially undergo osteogenesis. When cultured in differentiation media, adipose-derived stem cells (ASCs) undergoing terminal adipogenesis in 20% firming buffer (FB) scaffolds and osteogenesis in 40% and 60% FB scaffolds show the highest secretion of collagen as compared to other groups of scaffolds. Overall, this study demonstrates the three-way relationship between 3D scaffolds, ECM composition, and stem cell differentiation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1090-1101, 2016. PMID:26749566

  19. Fabrication of freestanding alginate microfibers and microstructures for tissue engineering applications.

    PubMed

    Szymanski, John M; Feinberg, Adam W

    2014-06-01

    Natural biopolymers such as alginate have become important materials for a variety of biotechnology applications including drug delivery, cell encapsulation and tissue engineering. This expanding use has spurred the development of new approaches to engineer these materials at the nano- and microscales to better control cell interactions. Here we describe a method to fabricate freestanding alginate-based microfibers and microstructures with tunable geometries down to approximately 3 µm. To do this, a polydimethylsiloxane stamp is used to micromold alginate or alginate-fibrin blends onto a sacrificial layer of thermally-sensitive poly(N-isopropylacrylamide) (PIPAAm). A warm calcium chloride solution is then used to crosslink the alginate and, upon cooling below the lower critical solution temperature (~32 °C), the PIPAAm layer dissolves and releases the alginate or alginate-fibrin as freestanding microfibers and microstructures. Proof-of-concept experiments demonstrate that C2C12 myoblasts seeded onto the alginate-fibrin microfibers polarize along the fiber length forming interconnected cell strands. Thus, we have developed the ability to engineer alginate-based microstructured materials that can selectively bind cells and direct cellular assembly. PMID:24695323

  20. Development and characterization of novel porous 3D alginate-cockle shell powder nanobiocomposite bone scaffold.

    PubMed

    Bharatham, B Hemabarathy; Abu Bakar, Md Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  1. Development and Characterization of Novel Porous 3D Alginate-Cockle Shell Powder Nanobiocomposite Bone Scaffold

    PubMed Central

    Bharatham, B. Hemabarathy; Abu Bakar, Md. Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  2. Engineering interconnected 3D vascular networks in hydrogels using molded sodium alginate lattice as the sacrificial template.

    PubMed

    Wang, Xue-Ying; Jin, Zi-He; Gan, Bo-Wen; Lv, Song-Wei; Xie, Min; Huang, Wei-Hua

    2014-08-01

    Engineering 3D perfusable vascular networks in vitro and reproducing the physiological environment of blood vessels is very challenging for tissue engineering and investigation of blood vessel function. Here, we engineer interconnected 3D microfluidic vascular networks in hydrogels using molded sodium alginate lattice as sacrificial templates. The sacrificial templates are rapidly replicated in polydimethylsiloxane (PDMS) microfluidic chips via Ca⁺²-crosslinking and then fully encapsulated in hydrogels. Interconnected channels with well controlled size and morphology are obtained by dissolving the monolayer or multilayer templates with EDTA solution. The human umbilical vein endothelial cells (HUVECs) are cultured on the channel linings and proliferated to form vascular lumens. The strong cell adhesion capability and adaptive response to shear stress demonstrate the excellent cytocompatibility of both the template and template-sacrificing process. Furthermore, the barrier function of the endothelial layer is characterized and the results show that a confluent endothelial monolayer is fully developed. Taken together, we develop a facile and rapid approach to engineer a vascular model that could be potentially used in physiological studies of vascular functions and vascular tissue engineering. PMID:24887141

  3. 3D sensors and micro-fabricated detector systems

    NASA Astrophysics Data System (ADS)

    Da Vià, Cinzia

    2014-11-01

    Micro-systems based on the Micro Electro Mechanical Systems (MEMS) technology have been used in miniaturized low power and low mass smart structures in medicine, biology and space applications. Recently similar features found their way inside high energy physics with applications in vertex detectors for high-luminosity LHC Upgrades, with 3D sensors, 3D integration and efficient power management using silicon micro-channel cooling. This paper reports on the state of this development.

  4. Microfluidic Fabrication of Bio-Inspired Microfibers with Controllable Magnetic Spindle-Knots for 3D Assembly and Water Collection.

    PubMed

    He, Xiao-Heng; Wang, Wei; Liu, Ying-Mei; Jiang, Ming-Yue; Wu, Fang; Deng, Ke; Liu, Zhuang; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

    2015-08-12

    A simple and flexible approach is developed for controllable fabrication of spider-silk-like microfibers with tunable magnetic spindle-knots from biocompatible calcium alginate for controlled 3D assembly and water collection. Liquid jet templates with volatile oil drops containing magnetic Fe3O4 nanoparticles are generated from microfluidics for fabricating spider-silk-like microfibers. The structure of jet templates can be precisely adjusted by simply changing the flow rates to tailor the structures of the resultant spider-silk-like microfibers. The microfibers can be well manipulated by external magnetic fields for controllably moving, and patterning and assembling into different 2D and 3D structures. Moreover, the dehydrated spider-silk-like microfibers, with magnetic spindle-knots for collecting water drops, can be controllably assembled into spider-web-like structures for excellent water collection. These spider-silk-like microfibers are promising as functional building blocks for engineering complex 3D scaffolds for water collection, cell culture, and tissue engineering. PMID:26192108

  5. Optical fabrication of lightweighted 3D printed mirrors

    NASA Astrophysics Data System (ADS)

    Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

    2015-09-01

    Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

  6. Performance evaluation of bipolar and tripolar excitations during nozzle-jetting-based alginate microsphere fabrication

    NASA Astrophysics Data System (ADS)

    Herran, C. Leigh; Huang, Yong; Chai, Wenxuan

    2012-08-01

    Microspheres, small spherical (polymeric) particles with or without second phase materials embedded or encapsulated, are important for many biomedical applications such as drug delivery and organ printing. Scale-up fabrication with the ability to precisely control the microsphere size and morphology has always been of great manufacturing interest. The objective of this work is to experimentally study the performance differences of bipolar and tripolar excitation waveforms in using drop-on-demand (DOD)-based single nozzle jetting for alginate microsphere fabrication. The fabrication performance has been evaluated based on the formability of alginate microspheres as a function of materials properties (sodium alginate and calcium chloride concentrations) and operating conditions. The operating conditions for each excitation include voltage rise/fall times, dwell times and excitation voltage amplitudes. Overall, the bipolar excitation is more robust in making spherical, monodispersed alginate microspheres as good microspheres for its wide working range of material properties and operating conditions, especially during the fabrication of highly viscous materials such as the 2% sodium alginate solution. For both bipolar and tripolar excitations, the sodium alginate concentration and the voltage dwell times should be carefully selected to achieve good microsphere formability.

  7. Fabrication, characterization, and biocompatibility of single-walled carbon nanotube-reinforced alginate composite scaffolds manufactured using freeform fabrication technique.

    PubMed

    Yildirim, Eda D; Yin, Xi; Nair, Kalyani; Sun, Wei

    2008-11-01

    Composite polymeric scaffolds from alginate and single-walled carbon nanotube (SWCNT) were produced using a freeform fabrication technique. The scaffolds were characterized for their structural, mechanical, and biological properties by scanning electron microscopy, Raman spectroscopy, tensile testing, and cell-scaffold interaction study. Three-dimensional hybrid alginate/SWCNT tissue scaffolds were fabricated in a multinozzle biopolymer deposition system, which makes possible to disperse and align SWCNTs in the alginate matrix. The structure of the resultant scaffolds was significantly altered due to SWCNT reinforcement, which was confirmed by Raman spectroscopy. Microtensile testing presented a reinforcement effect of SWCNT to the mechanical strength of the alginate struts. Ogden constitutive modeling was utilized to predict the stress-strain relationship of the alginate scaffold, which compared well with the experimental data. Cellular study by rat heart endothelial cell showed that the SWCNT incorporated in the alginate structure improved cell adhesion and proliferation. Our study suggests that hybrid alginate/SWCNT scaffolds are a promising biomaterial for tissue engineering applications. PMID:18506813

  8. Microfluidic fabrication of shape-tunable alginate microgels: effect of size and impact velocity.

    PubMed

    Hu, Yuandu; Azadi, Glareh; Ardekani, Arezoo M

    2015-04-20

    We report on a capillary-based microfluidic platform for the fabrication of non-spherical sodium alginate microgels. The sodium alginate droplets were crosslinked off-chip in a mixture of barium acetate and glycerol solution. Novel morphologies such as tear drop, lamp-like, mushroom-like, double-dimpled and bowl-like microgels were fabricated by controlling the size, impact velocity (at the crosslinking solution/oil interface), and concentration of sodium alginate solution. We monitored the microscale deformation process in situ at the interface and proposeed a deformation mechanism resulting in unique morphologies. Additionally, we constructed microgel superstructures by assembling the non-spherical alginate microgels to spherical poly(N-isopropylacrylamide) (pNIPAAm) microgels via electrostatic interaction. PMID:25662685

  9. Direct single-layered fabrication of 3D concavo convex patterns in nano-stereolithography

    NASA Astrophysics Data System (ADS)

    Lim, T. W.; Park, S. H.; Yang, D. Y.; Kong, H. J.; Lee, K. S.

    2006-09-01

    A nano-surfacing process (NSP) is proposed to directly fabricate three-dimensional (3D) concavo convex-shaped microstructures such as micro-lens arrays using two-photon polymerization (TPP), a promising technique for fabricating arbitrary 3D highly functional micro-devices. In TPP, commonly utilized methods for fabricating complex 3D microstructures to date are based on a layer-by-layer accumulating technique employing two-dimensional sliced data derived from 3D computer-aided design data. As such, this approach requires much time and effort for precise fabrication. In this work, a novel single-layer exposure method is proposed in order to improve the fabricating efficiency for 3D concavo convex-shaped microstructures. In the NSP, 3D microstructures are divided into 13 sub-regions horizontally with consideration of the heights. Those sub-regions are then expressed as 13 characteristic colors, after which a multi-voxel matrix (MVM) is composed with the characteristic colors. Voxels with various heights and diameters are generated to construct 3D structures using a MVM scanning method. Some 3D concavo convex-shaped microstructures were fabricated to estimate the usefulness of the NSP, and the results show that it readily enables the fabrication of single-layered 3D microstructures.

  10. Fabrication of Conductive 3D Gold-Containing Microstructures via Direct Laser Writing.

    PubMed

    Blasco, Eva; Müller, Jonathan; Müller, Patrick; Trouillet, Vanessa; Schön, Markus; Scherer, Torsten; Barner-Kowollik, Christopher; Wegener, Martin

    2016-05-01

    3D conductive microstructures containing gold are fabricated by simultaneous photopolymerization and photoreduction via direct laser writing. The photoresist employed consists of water-soluble polymers and a gold precursor. The fabricated microstructures show good conductivity and are successfully employed for 3D connections between gold pads. PMID:26953811

  11. Silicon-Embedding Approaches to 3-D Toroidal Inductor Fabrication

    SciTech Connect

    Yu, XH; Kim, M; Herrault, F; Ji, CH; Kim, J; Allen, MG

    2013-06-01

    This paper presents complementary-metal-oxide-semiconductor-compatible silicon-embedding techniques for on-chip integration of microelectromechanical-system devices with 3-D complex structures. By taking advantage of the "dead volume" within the bulk of the silicon wafer, functional devices with large profile can be embedded into the substrate without consuming valuable die area on the wafer surface or increasing the packaging complexity. Furthermore, through-wafer interconnects can be implemented to connect the device to the circuitry on the wafer surface. The key challenge of embedding structures within the wafer volume is processing inside deep trenches. To achieve this goal in an area-efficient manner, straight-sidewall trenches are desired, adding additional difficulty to the embedding process. Two approaches to achieve this goal are presented in this paper, i.e., a lithography-based process and a shadow-mask-based process. The lithography-based process utilizes a spray-coating technique and proximity lithography in combination with thick epoxy processing and laminated dry-film lithography. The shadow-mask-based process employs a specially designed 3-D silicon shadow mask to enable simultaneous metal patterning on both the vertical sidewall and the bottom surface of the trench during deposition, eliminating multiple lithography steps and reducing the process time. Both techniques have been demonstrated through the embedding of the topologically complex 3-D toroidal inductors into the silicon substrate for power supply on-chip (PwrSoC) applications. Embedded 3-D inductors that possess 25 turns and a diameter of 6 mm in a silicon trench of 300-mu m depth achieve overall inductances of 45-60 nH, dc resistances of 290-400 m Omega, and quality factors of 16-17.5 at 40-70 MHz.

  12. Fluorescence detector for capillary separations fabricated by 3D printing.

    PubMed

    Prikryl, Jan; Foret, Frantisek

    2014-12-16

    A simple inexpensive light-emitting diode (LED)-based fluorescence detector for detection in capillary separations is described. The modular design includes a separate high power LED source, detector head, designed in the epifluorescence arrangement, and capillary detection cells. The detector head and detection cells were printed using a 3D printer and assembled with commercially available optical components. Optical fibers were used for connecting the detector head to the LED excitation source and the photodetector module. Microscope objective or high numerical aperture optical fiber were used for collection of the fluorescence emission from the fused silica separation capillary. As an example, mixture of oligosaccharides labeled by 8-aminopyrene-1,3,6-trisulfonate (APTS) was separated by capillary zone electrophoresis and detected by the described detector. The performance of the detector was compared with both a semiconductor photodiode and photomultiplier as light sensing elements. The main advantages of the 3D printed parts, compared to the more expensive alternatives from the optic component suppliers, include not only cost reduction, but also easy customization of the spatial arrangement, modularity, miniaturization, and sharing of information between laboratories for easy replication or further modifications of the detector. All information and files necessary for printing the presented detector are enclosed in the Supporting Information. PMID:25427247

  13. Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

    PubMed

    Attalla, R; Ling, C; Selvaganapathy, P

    2016-02-01

    The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks. PMID:26842949

  14. Optimizing fabrication of electrodeposited 3D surface features

    SciTech Connect

    Steffani, C., LLNL

    1998-07-01

    Selective electrodeposition onto specially masked surfaces (producing blind holes with non-conductive side walls) has been investigated. The thick masks are low cost polymer sheet into which holes and other patterns are machined. Plating with this type of masking system is one method of fabricating medium aspect ratio metallic structures (structures whose width to length ratio is greater than 10/1). The experiment was conducted with deposits of OFC copper from an acid sulfate solution, but similar results are expected with other metals. Structure diameter varied from 0.25 mm to 3.8 mm (0.01`` to 0.150``). The effect of current density, electrolyte concentration, solution temperature, and agitation on deposition rate were investigated. Deposit quality, deposition rate, and optimal plating parameters were evaluated.

  15. The fabrication of 3-D nanostructures by a low- voltage EBL

    NASA Astrophysics Data System (ADS)

    Oh, Seung Hun; Kim, Jae Gu; Kim, Chang Seok; Choi, Doo Sun; Chang, Sunghwan; Jeong, Myung Yung

    2011-02-01

    Three-dimensional (3-D) structures are used in many applications, including the fabrication of opto-electronic and bio-MEMS devices. Among the various fabrication techniques available for 3-D structures, nano imprint lithography (NIL) is preferred for producing nanoscale 3-D patterns because of its simplicity, relatively short processing time, and high manufacturing precision. For efficient replication in NIL, a precise 3-D stamp must be used as an imprinting tool. Hence, we attempted the fabrication of original 3-D master molds by low-voltage electron beam lithography (EBL). We then fabricated polydimethylsiloxane (PDMS) stamps from the original 3-D mold via replica molding with ultrasonic vibration.First, we experimentally analyzed the characteristics of low-voltage EBL in terms of various parameters such as resist thickness, acceleration voltage, aperture size, and baking temperature. From these e-beam exposure experiments, we found that the exposure depth and width were almost saturated at 3 kV or lesser, even when the electron dosage was increased. This allowed for the fabrication of various stepped 3-D nanostructures at a low voltage. In addition, by using line-dose EBL, V-groove patterns could be fabricated on a cured electron resist (ER) at a low voltage and low baking temperature. Finally, the depth variation could be controlled to within 10 nm through superposition exposure at 1 kV. From these results, we determined the optimum electron beam exposure conditions for the fabrication of various 3-D structures on ERs by low-voltage EBL. We then fabricated PDMS stamps via the replica molding process.

  16. Metal nanoparticle direct inkjet printing for low-temperature 3D micro metal structure fabrication

    NASA Astrophysics Data System (ADS)

    Ko, Seung Hwan; Chung, Jaewon; Hotz, Nico; Nam, Koo Hyun; Grigoropoulos, Costas P.

    2010-12-01

    Inkjet printing of functional materials is a key technology toward ultra-low-cost, large-area electronics. We demonstrate low-temperature 3D micro metal structure fabrication by direct inkjet printing of metal nanoparticles (NPs) as a versatile, direct 3D metal structuring approach representing an alternative to conventional vacuum deposition and photolithographic methods. Metal NP ink was inkjet-printed to exploit the large melting temperature drop of the nanomaterial and the ease of the NP ink formulation. Parametric studies on the basic conditions for stable 3D inkjet printing of NP ink were carried out. Furthermore, diverse 3D metal microstructures, including micro metal pillar arrays, helices, zigzag and micro bridges were demonstrated and electrical characterization was performed. Since the process requires low temperature, it carries substantial potential for fabrication of electronics on a plastic substrate.

  17. Laser fabrication of 2D and 3D metal nanoparticle structures and arrays.

    PubMed

    Kuznetsov, A I; Kiyan, R; Chichkov, B N

    2010-09-27

    A novel method for fabrication of 2D and 3D metal nanoparticle structures and arrays is proposed. This technique is based on laser-induced transfer of molten metal nanodroplets from thin metal films. Metal nanoparticles are produced by solidification of these nanodroplets. The size of the transferred nanoparticles can be controllably changed in the range from 180 nm to 1500 nm. Several examples of complex 2D and 3D microstructures generated form gold nanoparticles are demonstrated. PMID:20941016

  18. Using double-poured alginate impressions to fabricate bleaching trays.

    PubMed

    Haywood, V B; Powe, A

    1998-01-01

    Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal. PMID:9656923

  19. Fabrication of 3D solenoid microcoils in silica glass by femtosecond laser wet etch and microsolidics

    NASA Astrophysics Data System (ADS)

    Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Du, Guangqing; Hou, Xun

    2015-02-01

    This paper reports a flexible fabrication method for 3D solenoid microcoils in silica glass. The method consists of femtosecond laser wet etching (FLWE) and microsolidics process. The 3D microchannel with high aspect ratio is fabricated by an improved FLWE method. In the microsolidics process, an alloy was chosen as the conductive metal. The microwires are achieved by injecting liquid alloy into the microchannel, and allowing the alloy to cool and solidify. The alloy microwires with high melting point can overcome the limitation of working temperature and improve the electrical property. The geometry, the height and diameter of microcoils were flexibly fabricated by the pre-designed laser writing path, the laser power and etching time. The 3D microcoils can provide uniform magnetic field and be widely integrated in many magnetic microsystems.

  20. Development of an indirect solid freeform fabrication process based on microstereolithography for 3D porous scaffolds

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Wook; Seol, Young-Joon; Cho, Dong-Woo

    2009-01-01

    Scaffold fabrication using solid freeform fabrication (SFF) technology is a hot topic in tissue engineering. Here, we present a new indirect SFF technology based on microstereolithography (MSTL), which has the highest resolution of all SFF methods, to construct a three-dimensional (3D) porous scaffold by combining SFF with molding technology. To realize this indirect method, we investigated and modified a water-soluble photopolymer. We used MSTL technology to fabricate a high-resolution 3D porous mold composed of the modified polymer. The mold can be removed using an appropriate solvent. We tested two materials, polycaprolactone and calcium sulfate hemihydrate, using the molding process, and developed a lost-mold shape forming process by dissolving the mold. This procedure demonstrated that the proposed method can yield scaffold pore sizes as small as 60-70 µm. In addition, cytotoxicity test results indicated that the proposed process is feasible for producing 3D porous scaffolds.

  1. 3D printed auxetic forms on knitted fabrics for adjustable permeability and mechanical properties

    NASA Astrophysics Data System (ADS)

    Grimmelsmann, N.; Meissner, H.; Ehrmann, A.

    2016-07-01

    The 3D printing technology can be applied into manufacturing primary shaping diverse products, from models dealing as examples for future products that will be produced with another technique, to useful objects. Since 3D printing is nowadays significantly slower than other possibilities to manufacture items, such as die casting, it is often used for small parts that are produced in small numbers or for products that cannot be created in another way. Combinations of 3D printing with other objects, adding novel functionalities to them, are thus favourable to a complete primary shaping process. Textile fabrics belong to the objects whose mechanical and other properties can notably be modified by adding 3D printed forms. This article mainly reports on a new possibility to change the permeability of textile fabrics by 3D printing auxetic forms, e.g. for utilising them in textile filters. In addition, auxetic forms 3D printed on knitted fabrics can bring about mechanical properties that are conducive to tensile constructions.

  2. Novel Target Fabrication Using 3D Printing Developed at University of Michigan

    NASA Astrophysics Data System (ADS)

    Klein, Sallee R.; Deininger, Michael; Gillespie, Robb S.; Di Stefano, Carlos A.; MacDonald, Michael J.; J-E Manuel, Mario; Young, Rachel P.; Kuranz, Carolyn C.; Keiter, Paul A.; Drake, R. Paul

    2016-04-01

    The University of Michigan has been fabricating targets for high-energy-density experiments for the past decade. We utilize the technique of machined acrylic bodies and mating components acting as constraints to build repeatable targets. Combining 3D printing with traditional machining, we are able to take advantage of the very best part of both aspects of manufacturing. Here we present several recent campaigns to act as showcase and introduction of our techniques and our experience with 3D printing, effecting how we utilize 3D printing in our target builds.

  3. A Review on Energy Harvesting Using 3D Printed Fabrics for Wearable Electronics

    NASA Astrophysics Data System (ADS)

    Gowthaman, Swaminathan; Chidambaram, Gowri Shankar; Rao, Dilli Babu Govardhana; Subramya, Hemakumar Vyudhayagiri; Chandrasekhar, Udhayagiri

    2016-06-01

    Embedding of energy harvesting systems into wearable health and environment monitoring systems, like integration of smart piezoelectric fibers into soldier fabric structures opens up avenues in generating electricity from natural mechanical movements for self-powering of wearable electronics. Emergence of multitudinous of materials and manufacturing technologies has enabled realization of various energy harvesting systems from mechanical movements. The materials and manufacturing related to 3D printing of energy harvesting fabrics are reviewed in this paper. State-of-the-art energy harvesting sources are briefly described following which an in-depth analysis on the materials and 3D printing techniques for energy harvesting fabrics are presented. While tremendous motivation and opportunity exists for wider-scale adoption of 3D printing for this niche area, the success depends on efficient design of three critical factors namely materials, process and structure. The present review discusses on the complex issues of materials selection, modelling and processing of 3D printed fabrics. The paper culminates by presenting a discussion on how future advancements in 3D printing technology might be useful for development of wearable electronics.

  4. Efficient fabrication method of nano-grating for 3D holographic display with full parallax views.

    PubMed

    Wan, Wenqiang; Qiao, Wen; Huang, Wenbin; Zhu, Ming; Fang, Zongbao; Pu, Donglin; Ye, Yan; Liu, Yanhua; Chen, Linsen

    2016-03-21

    Without any special glasses, multiview 3D displays based on the diffractive optics can present high resolution, full-parallax 3D images in an ultra-wide viewing angle. The enabling optical component, namely the phase plate, can produce arbitrarily distributed view zones by carefully designing the orientation and the period of each nano-grating pixel. However, such 3D display screen is restricted to a limited size due to the time-consuming fabricating process of nano-gratings on the phase plate. In this paper, we proposed and developed a lithography system that can fabricate the phase plate efficiently. Here we made two phase plates with full nano-grating pixel coverage at a speed of 20 mm2/mins, a 500 fold increment in the efficiency when compared to the method of E-beam lithography. One 2.5-inch phase plate generated 9-view 3D images with horizontal-parallax, while the other 6-inch phase plate produced 64-view 3D images with full-parallax. The angular divergence in horizontal axis and vertical axis was 1.5 degrees, and 1.25 degrees, respectively, slightly larger than the simulated value of 1.2 degrees by Finite Difference Time Domain (FDTD). The intensity variation was less than 10% for each viewpoint, in consistency with the simulation results. On top of each phase plate, a high-resolution binary masking pattern containing amplitude information of all viewing zone was well aligned. We achieved a resolution of 400 pixels/inch and a viewing angle of 40 degrees for 9-view 3D images with horizontal parallax. In another prototype, the resolution of each view was 160 pixels/inch and the view angle was 50 degrees for 64-view 3D images with full parallax. As demonstrated in the experiments, the homemade lithography system provided the key fabricating technology for multiview 3D holographic display. PMID:27136814

  5. 3D Porous Calcium-Alginate Scaffolds Cell Culture System Improved Human Osteoblast Cell Clusters for Cell Therapy

    PubMed Central

    Chen, Ching-Yun; Ke, Cherng-Jyh; Yen, Ko-Chung; Hsieh, Hui-Chen; Sun, Jui-Sheng; Lin, Feng-Huei

    2015-01-01

    Age-related orthopedic disorders and bone defects have become a critical public health issue, and cell-based therapy is potentially a novel solution for issues surrounding bone tissue engineering and regenerative medicine. Long-term cultures of primary bone cells exhibit phenotypic and functional degeneration; therefore, culturing cells or tissues suitable for clinical use remain a challenge. A platform consisting of human osteoblasts (hOBs), calcium-alginate (Ca-Alginate) scaffolds, and a self-made bioreactor system was established for autologous transplantation of human osteoblast cell clusters. The Ca-Alginate scaffold facilitated the growth and differentiation of human bone cell clusters, and the functionally-closed process bioreactor system supplied the soluble nutrients and osteogenic signals required to maintain the cell viability. This system preserved the proliferative ability of cells and cell viability and up-regulated bone-related gene expression and biological apatite crystals formation. The bone-like tissue generated could be extracted by removal of calcium ions via ethylenediaminetetraacetic acid (EDTA) chelation, and exhibited a size suitable for injection. The described strategy could be used in therapeutic application and opens new avenues for surgical interventions to correct skeletal defects. PMID:25825603

  6. Formation of Neural Networks in 3D Scaffolds Fabricated by Means of Laser Microstereolithography.

    PubMed

    Vedunova, M V; Timashev, P S; Mishchenko, T A; Mitroshina, E V; Koroleva, A V; Chichkov, B N; Panchenko, V Ya; Bagratashvili, V N; Mukhina, I V

    2016-08-01

    We developed and tested new 3D scaffolds for neurotransplantation. Scaffolds of predetermined architectonic were prepared using microstereolithography technique. Scaffolds were highly biocompatible with the nervous tissue cells. In vitro studies showed that the material of fabricated scaffolds is not toxic for dissociated brain cells and promotes the formation of functional neural networks in the matrix. These results demonstrate the possibility of fabrication of tissue-engineering constructs for neurotransplantation based on created scaffolds. PMID:27595153

  7. Fabrication of 3D high aspect ratio PDMS microfluidic networks with a hybrid stamp.

    PubMed

    Kung, Yu-Chun; Huang, Kuo-Wei; Fan, Yu-Jui; Chiou, Pei-Yu

    2015-04-21

    We report a novel methodology for fabricating large-area, multilayer, thin-film, high aspect ratio, 3D microfluidic structures with through-layer vias and open channels that can be bonded between hard substrates. It is realized by utilizing a hybrid stamp with a thin plastic sheet embedded underneath a PDMS surface. This hybrid stamp solves an important edge protrusion issue during PDMS molding while maintaining necessary stamp elasticity to ensure the removal of PDMS residues at through-layer regions. Removing edge protrusion is a significant progress toward fabricating 3D structures since high aspect ratio PDMS structures with flat interfaces can be realized to facilitate multilayer stacking and bonding to hard substrates. Our method also allows for the fabrication of 3D deformable channels, which can lead to profound applications in electrokinetics, optofluidics, inertial microfluidics, and other fields where the shape of the channel cross section plays a key role in device physics. To demonstrate, as an example, we have fabricated a microfluidic channel by sandwiching two 20 μm wide, 80 μm tall PDMS membranes between two featureless ITO glass substrates. By applying electrical bias to the two ITO substrates and pressure to deform the thin membrane sidewalls, strong electric field enhancement can be generated in the center of a channel to enable 3D sheathless dielectrophoretic focusing of biological objects including mammalian cells and bacteria at a flow speed up to 14 cm s(-1). PMID:25710255

  8. Formation and properties of 3D metamaterial composites fabricated using nanometer scale laser lithography (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Prokes, Sharka M.; Perkins, Frank K.; Glembocki, Orest J.

    2015-08-01

    Metamaterials designed for the visible or near IR wavelengths require patterning on the nanometer scale. To achieve this, e-beam lithography is used, but it is extremely difficult and can only produce 2D structures. A new alternative technique to produce 2D and 3D structures involves laser fabrication using the Nanoscribe 3D laser lithography system. This is a direct laser writing technique which can form arbitrary 3D nanostructures on the nanometer scale and is based on multi-photon polymerization. We are creating 2D and 3D metamaterials via this technique, and subsequently conformally coating them using Atomic Layer Deposition of oxides and Ag. We will discuss the optical properties of these novel composite structures and their potential for dual resonant metamaterials.

  9. Fabrication of low cost soft tissue prostheses with the desktop 3D printer

    PubMed Central

    He, Yong; Xue, Guang-huai; Fu, Jian-zhong

    2014-01-01

    Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods. PMID:25427880

  10. Fabrication of low cost soft tissue prostheses with the desktop 3D printer

    NASA Astrophysics Data System (ADS)

    He, Yong; Xue, Guang-Huai; Fu, Jian-Zhong

    2014-11-01

    Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

  11. Effect of Frictions on the Ballistic Performance of a 3D Warp Interlock Fabric: Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Ha-Minh, Cuong; Boussu, François; Kanit, Toufik; Crépin, David; Imad, Abdellatif

    2012-06-01

    3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply the mechanical properties of yarns to them. The tool shows many advantages over existing software. It is very handy in use with an organization of the functions in menu and using a graphic interface. It can describe correctly the geometry of all textile woven fabrics. With this tool, the orientation of the local axes of finite elements following the yarn direction facilitates defining the yarn mechanical properties in a numerical model. This tool can be largely applied because it is compatible with popular finite element codes such as Abaqus, Ansys, Radioss etc. Thanks to this tool, a finite element model was carried out to describe a ballistic impact on a 3D warp interlock Kevlar KM2® fabric. This work focuses on studying the effect of friction onto the ballistic impact behavior of this textile interlock structure. Results showed that the friction among yarns affects considerably on the impact behavior of this fabric. The effect of the friction between projectile and yarn is less important. The friction plays an important role in keeping the fabric structural stability during the impact event. This phenomenon explained why the projectile is easier to penetrate this 3D warp interlock fabric in the no-friction case. This result also indicates that the ballistic performance of the interlock woven fabrics can be improved by using fibers with great friction coefficients.

  12. Facile 3D Metal Electrode Fabrication for Energy Applications via Inkjet Printing and Shape Memory Polymer

    NASA Astrophysics Data System (ADS)

    Roberts, R. C.; Wu, J.; Hau, N. Y.; Chang, Y. H.; Feng, S. P.; Li, D. C.

    2014-11-01

    This paper reports on a simple 3D metal electrode fabrication technique via inkjet printing onto a thermally contracting shape memory polymer (SMP) substrate. Inkjet printing allows for the direct patterning of structures from metal nanoparticle bearing liquid inks. After deposition, these inks require thermal curing steps to render a stable conductive film. By printing onto a SMP substrate, the metal nanoparticle ink can be cured and substrate shrunk simultaneously to create 3D metal microstructures, forming a large surface area topology well suited for energy applications. Polystyrene SMP shrinkage was characterized in a laboratory oven from 150-240°C, resulting in a size reduction of 1.97-2.58. Silver nanoparticle ink was patterned into electrodes, shrunk, and the topology characterized using scanning electron microscopy. Zinc-Silver Oxide microbatteries were fabricated to demonstrate the 3D electrodes compared to planar references. Characterization was performed using 10M potassium hydroxide electrolyte solution doped with zinc oxide (57g/L). After a 300s oxidation at 3Vdc, the 3D electrode battery demonstrated a 125% increased capacity over the reference cell. Reference cells degraded with longer oxidations, but the 3D electrodes were fully oxidized for 4 hours, and exhibited a capacity of 5.5mA-hr/cm2 with stable metal performance.

  13. Fabrication of 3D microfluidic structures inside glass by femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Sugioka, Koji; Cheng, Ya

    2014-01-01

    Femtosecond lasers have opened up new avenues in materials processing due to their unique characteristics of ultrashort pulse widths and extremely high peak intensities. One of the most important features of femtosecond laser processing is that a femtosecond laser beam can induce strong absorption in even transparent materials due to nonlinear multiphoton absorption. This makes it possible to directly create three-dimensional (3D) microfluidic structures in glass that are of great use for fabrication of biochips. For fabrication of the 3D microfluidic structures, two technical approaches are being attempted. One of them employs femtosecond laser-induced internal modification of glass followed by wet chemical etching using an acid solution (Femtosecond laser-assisted wet chemical etching), while the other one performs femtosecond laser 3D ablation of the glass in distilled water (liquid-assisted femtosecond laser drilling). This paper provides a review on these two techniques for fabrication of 3D micro and nanofluidic structures in glass based on our development and experimental results.

  14. A Patterned 3D Silicon Anode Fabricated by Electrodeposition on a Virus-Structured Current Collector

    SciTech Connect

    Chen, X L; Gerasopoulos, K; Guo, J C; Brown, A; Wang, Chunsheng; Ghodssi, Reza; Culver, J N

    2010-11-09

    Electrochemical methods were developed for the deposition of nanosilicon onto a 3D virus-structured nickel current collector. This nickel current collector is composed of self-assembled nanowire-like rods of genetically modified tobacco mosaic virus (TMV1cys), chemically coated in nickel to create a complex high surface area conductive substrate. The electrochemically depo­sited 3D silicon anodes demonstrate outstanding rate performance, cycling stability, and rate capability. Electrodeposition thus provides a unique means of fabricating silicon anode materials on complex substrates at low cost.

  15. Fabrication of photo-crosslinked chitosan- gelatin scaffold in sodium alginate hydrogel for chondrocyte culture.

    PubMed

    Zhao, Peng; Deng, Cuijun; Xu, Hongzhen; Tang, Xing; He, Hailong; Lin, Chao; Su, Jiansheng

    2014-01-01

    Photo-crosslinked chitosan-gelatin scaffolds were fabricated and applied for chondrocyte culture in vitro. Photocurable methacryloyl chitosan was synthesized and characterized by FTIR and 1H NMR, respectively. Microstructure and mechanical properties of the chitosan-gelatin scaffold treated with or without EDC as crosslinking agent were analyzed by scanning electronic microscopy (SEM), compression and viscoelastic measurement. It is demonstrated that EDC-treated chitosan-gelatin scaffold possesses better porous structure and improved mechanical properties. Photo-crosslinked chitosan-gelatin scaffold could be further integrated in sodium alginate hydrogel using calcium chloride to support proliferation of chondrocytes for over 21 days and maintain spherical phenotype, as evaluated by AlamarBlue assay and SEM, respectively, implying that the chitosan-gelatin-hydrogel system exhibits great cyto-biocompatibility. Results of this study show that photo-crosslinked chitosan-gelatin scaffold in sodium alginate hydrogel is suited as a scaffold candidate for cartilage tissue engineering. PMID:24211948

  16. 3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.

    PubMed

    Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon

    2016-07-28

    Acne is a multifactorial inflammatory skin disease with high prevalence. In this work, the potential of 3D printing to produce flexible personalised-shape anti-acne drug (salicylic acid) loaded devices was demonstrated by two different 3D printing (3DP) technologies: Fused Deposition Modelling (FDM) and stereolithography (SLA). 3D scanning technology was used to obtain a 3D model of a nose adapted to the morphology of an individual. In FDM 3DP, commercially produced Flex EcoPLA™ (FPLA) and polycaprolactone (PCL) filaments were loaded with salicylic acid by hot melt extrusion (HME) (theoretical drug loading - 2% w/w) and used as feedstock material for 3D printing. Drug loading in the FPLA-salicylic acid and PCL-salicylic acid 3D printed patches was 0.4% w/w and 1.2% w/w respectively, indicating significant thermal degradation of drug during HME and 3D printing. Diffusion testing in Franz cells using a synthetic membrane revealed that the drug loaded printed samples released <187μg/cm(2) within 3h. FPLA-salicylic acid filament was successfully printed as a nose-shape mask by FDM 3DP, but the PCL-salicylic acid filament was not. In the SLA printing process, the drug was dissolved in different mixtures of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) (PEG) that were solidified by the action of a laser beam. SLA printing led to 3D printed devices (nose-shape) with higher resolution and higher drug loading (1.9% w/w) than FDM, with no drug degradation. The results of drug diffusion tests revealed that drug diffusion was faster than with the FDM devices, 229 and 291μg/cm(2) within 3h for the two formulations evaluated. In this study, SLA printing was the more appropriate 3D printing technology to manufacture anti-acne devices with salicylic acid. The combination of 3D scanning and 3D printing has the potential to offer solutions to produce personalised drug loaded devices, adapted in shape and size to individual patients. PMID:27189134

  17. Fundamental Characteristics of Bioprint on Calcium Alginate Gel

    NASA Astrophysics Data System (ADS)

    Umezu, Shinjiro; Hatta, Tatsuru; Ohmori, Hitoshi

    2013-05-01

    The goal of this study is to fabricate precision three-dimensional (3D) biodevices those are micro fluidics and artificial organs utilizing digital fabrication. Digital fabrication is fabrication method utilizing inkjet technologies. Electrostatic inkjet is one of the inkjet technologies. The electrostatic inkjet method has following two merits; those are high resolution to print and ability to eject highly viscous liquid. These characteristics are suitable to print biomaterials precisely. We are now applying for bioprint. In this paper, the electrostatic inkjet method is applied for fabrication of 3D biodevices that has cave like blood vessel. When aqueous solution of sodium alginate is printed to aqueous solution of calcium chloride, calcium alginate is produced. 3D biodevices are fabricated in case that calcium alginate is piled.

  18. A simple approach for the fabrication of 3D microelectrodes for impedimetric sensing

    NASA Astrophysics Data System (ADS)

    Tahsin Guler, Mustafa; Bilican, Ismail; Agan, Sedat; Elbuken, Caglar

    2015-09-01

    In this paper, we present a very simple method to fabricate three-dimensional (3D) microelectrodes integrated with microfluidic devices. We form the electrodes by etching a microwire placed across a microchannel. For precise control of the electrode spacing, we employ a hydrodynamic focusing microfluidic device and control the width of the etching solution stream. The focused widths of the etchant solution and the etching time determine the gap formed between the electrodes. Using the same microfluidic device, we can fabricate integrated 3D electrodes with different electrode gaps. We have demonstrated the functionality of these electrodes using an impedimetric particle counting setup. Using 3D microelectrodes with a diameter of 25 μm, we have detected 6 μm-diameter polystyrene beads in a buffer solution as well as erythrocytes in a PBS solution. We study the effect of electrode spacing on the signal-to-noise ratio of the impedance signal and we demonstrate that the smaller the electrode spacing the higher the signal obtained from a single microparticle. The sample stream is introduced to the system using the same hydrodynamic focusing device, which ensures the alignment of the sample in between the electrodes. Utilising a 3D hydrodynamic focusing approach, we force all the particles to go through the sensing region of the electrodes. This fabrication scheme not only provides a very low-cost and easy method for rapid prototyping, but which can also be used for applications requiring 3D electric field focused through a narrow section of the microchannel.

  19. CMOS compatible fabrication of 3D photonic crystals by nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Eibelhuber, M.; Uhrmann, T.; Glinsner, T.

    2015-03-01

    Nanoimprinting techniques are an attractive solution for next generation lithography methods for several areas including photonic devices. A variety of potential applications have been demonstrated using nanoimprint lithography (NIL) (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. Nanoimprint lithography is considered for bridging the gap from R and D to high volume manufacturing. In addition, it is capable to adapt to the needs of the fragmented and less standardized photonic market easily. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. It has been shown that UVNIL using a multiple layer approach is well suited to fabricate a 3D woodpile photonic crystal. The necessary alignment accuracies below 100nm were achieved using a simple optical method. In order to obtain sufficient alignment of the stacks to each other, a two stage alignment process is performed: at first proximity alignment is done followed by the Moiré alignment in soft contact with the substrate. Multiple steps of imprinting, etching, Si deposition and chemical mechanical polishing were implemented to create high quality 3D photonic crystals with up to 5 layers. This work has proven the applicability of nanoimprint lithography in a CMOS compatible process on 3D photonic crystals with alignment accuracy down to 100nm. Optimizing the processes will allow scaling up these structures on full wafers while still meeting the requirements of the designated devices.

  20. Fabrication of 3D metal/polymer microstructures by site-selective metal coating

    NASA Astrophysics Data System (ADS)

    Takeyasu, N.; Tanaka, T.; Kawata, S.

    2008-02-01

    Three-dimensional silver/polymer conjugated microstructures were fabricated by site-selective metal deposition on photopolymer structures in the sub-micrometer scale. Photopolymerizable resins with and without an amide group were independently prepared, and a three-dimensional polymer structure was fabricated with those resins by means of the two-photon-induced photopolymerization technique to confine the photopolymerization to a sub-micrometer volume. Silver was selectively deposited on the surface of the amide-containing polymer parts by electroless plating. This method can provide 3D arbitrary silver/polymer composite microstructures with sub-micrometer resolution.

  1. 3D printing method for freeform fabrication of optical phantoms simulating heterogeneous biological tissue

    NASA Astrophysics Data System (ADS)

    Wang, Minjie; Shen, Shuwei; Yang, Jie; Dong, Erbao; Xu, Ronald

    2014-03-01

    The performance of biomedical optical imaging devices heavily relies on appropriate calibration. However, many of existing calibration phantoms for biomedical optical devices are based on homogenous materials without considering the multi-layer heterogeneous structures observed in biological tissue. Using such a phantom for optical calibration may result in measurement bias. To overcome this problem, we propose a 3D printing method for freeform fabrication of tissue simulating phantoms with multilayer heterogeneous structure. The phantom simulates not only the morphologic characteristics of biological tissue but also absorption and scattering properties. The printing system is based on a 3D motion platform with coordinated control of the DC motors. A special jet nozzle is designed to mix base, scattering, and absorption materials at different ratios. 3D tissue structures are fabricated through layer-by-layer printing with selective deposition of phantom materials of different ingredients. Different mixed ratios of base, scattering and absorption materials have been tested in order to optimize the printing outcome. A spectrometer and a tissue spectrophotometer are used for characterizing phantom absorption and scattering properties. The goal of this project is to fabricate skin tissue simulating phantoms as a traceable standard for the calibration of biomedical optical spectral devices.

  2. An appropriate selection of a 3D alginate culture model for hepatic Huh-7 cell line encapsulation intended for viral studies.

    PubMed

    Tran, Nhu Mai; Dufresne, Murielle; Duverlie, Gilles; Castelain, Sandrine; Défarge, Christian; Paullier, Patrick; Legallais, Cecile

    2013-01-01

    Three-dimensional (3D) culture systems have been introduced to provide cells with a biomimetic environment that is similar to in vivo conditions. Among the polymeric molecules available, sodium-alginate (Na-alg) salt is a material that is currently employed in different areas of drug delivery and tissue engineering, because it offers biocompatibility and optimal chemical properties, and its gelation with calcium chloride provides calcium-alginate (Ca-alg) scaffolds with mechanical stability and relative permeability. In this work, four different preparations of Ca-alg beads with varying Na-alg viscosity and concentration were used for a human hepatoma cell line (Huh-7) encapsulation. The effects of Ca-alg bead preparation on structural cell organization, liver-specific functions, and the expression of specific receptors implicated in hepatotropic virus permissivity were evaluated. Hepatic cells were cultured in 500 μm diameter Ca-alg beads for 7 days under dynamic conditions. For all culture systems, cell viability reached almost 100% at day 7. Cell proliferation was concomitantly followed by hepatocyte organization in aggregates, which adopted two different morphologies (spheroid aggregates or multicellular channel-like structures), depending on Ca-alg bead preparation. These cellular organizations established a real 3D hepatocyte architecture with cell polarity, cell junctions, and abundant bile canaliculi possessing microvillus-lined channels. The functionality of these 3D cultures was confirmed by the production of albumin and the exhibition of CYP1A activity over culture time, which were variable, according to Ca-alg bead condition. The expression of specific receptors of hepatitis C virus by Huh-7 cells suggests encouraging data for the further development of a new viral culture system in Ca-alg beads. In summary, this 3D hepatic cell culture represents a promising physiologically relevant system for further in vitro studies and demonstrates that an

  3. Microelectro discharge machining: an innovative method for the fabrication of 3D microdevices

    NASA Astrophysics Data System (ADS)

    Lesche, Claudia; Krah, Thomas; Büttgenbach, Stephanus

    2011-06-01

    This paper reports on the potential of microelectro discharge machining (μEDM) as an innovative method for the fabrication of 3D microdevices. To demonstrate the wide capabilities of μEDM two different high-potential 3D microsystems - a microfluidic device for the dispersion of nanoparticles and a star probe for microcoordinate metrology - are presented. For the fabrication of these microdevices a μEDM-milling machine with integrated microwire electro discharge grinding (μWEDG) module is utilized. To gain optimized process conditions as well as a high surface quality an adequate adaption of the single erosion parameters such as energy, pulse frequency and spark gap has to be carried out and are discussed below. The dispersion micromodule is used for pharmaceutical screening applications in a high pressure range up to 2000 bar. At the channel bottom a surface roughness of Ra = 80 nm is achieved. In case of the star probe it is possible to produce shaft and sphere out of one piece. The fabricated stylus elements have sphere diameters of 40-200 μm. For both applications μEDM offers a flexible, precise, effective and cost-efficient fabrication method for the machining of hard and resistant materials.

  4. Long-term viability and proliferation of alginate-encapsulated 3-D HepG2 aggregates formed in an ultrasound trap.

    PubMed

    Bazou, D; Coakley, W T; Hayes, A J; Jackson, S K

    2008-08-01

    We report proof of principle here of a gel encapsulation technique that departs from the minimum surface area to volume restriction of spherical microcapsules and allows gelation of preformed high-density (>or=2x10(4) cells/aggregate) 3-D HepG2 cell aggregates. The process involves forming a discoid 3-D cell aggregate in an ultrasound standing wave trap (USWT), which is subsequently recovered and encapsulated in alginate/CaCl2 hydrogel. The size of the ultrasound-formed aggregates was dependent upon the initial cell concentration, and was in the range of 0.4-2.6 mm in diameter (for cell concentrations ranging between 10(4) and 5x10(6)/ml). At low cell concentrations (or=10(6)/ml, 3-D aggregates were generated. Cells in non- and encapsulated 3-D HepG2 aggregates remained 70-80% viable over 10 days in culture. The proliferative activity of the aggregates resulted in the doubling of the aggregate cell number and a subsequent increase in the aggregate thickness, while albumin secretion levels in encapsulated aggregates was 4.5 times higher compared to non-encapsulated, control aggregates. The results reported here suggest that the ultrasound trap can provide an alternative, novel approach of hydrogel cell encapsulation and thus rapidly (within 5 min) produce in vitro models for hepatocyte functional studies (for example, toxicity studies particularly if primary hepatocytes are used) in a tissue-mimetic manner. PMID:18490133

  5. The study of simulated microgravity effects on cardiac myocytes using a 3D heart tissue-equivalent model encapsulated in alginate microbeads

    NASA Astrophysics Data System (ADS)

    Li, Yu; Tian, Weiming; Zheng, Hongxia; Yu, Lei; Zhang, Yao; Han, Fengtong

    Long duration spaceflight may increase the risk and occurrence of potentially life-threatening heart rhythm disturbances associated with alterations of cardiac myocytes, myocyte connec-tivity, and extracellular matrix resulting from prolonged exposure to zero-or low-gravity. For understanding of the effects of microgravity, either traditional 2-dimensional (2D) cell cultures of adherent cell populations or animal models were typically used. The 2D in vitro systems do not allow assessment of the dynamic effects of intercellular interactions within tissues, whereas potentially confounding factors tend to be overlooked in animal models. Therefore novel cell culture model representative of the cellular interactions and with extracellular matrix present in tissues needs to be used. In this study, 3D multi-cellular heart tissue-equivalent model was constructed by culturing neonatal rat myocardial cells in alginate microbeads for one week. With this model we studied the simulated microgravity effects on myocardiocytes by incubat-ing the microbeads in NASA rotary cell culture system with a rate of 15rpm. Cytoskeletal changes, mitochondrial membrane potential and reactive oxygen production were studied after incubating for 24h, 48h and 72h respectively. Compared with 3D ground-culture group, sig-nificant cytoskeleton depolymerization characterized by pseudo-feet disappearance, significant increase of mitochondrial membrane potential, and greater reactive oxygen production were observed in after incubating 24h, 48h, and 72h, in NASA system. The beating rate of 3D heart tissue-equivalent decreased significantly at 24h, and all the samples stopped beating after 48h incubation while the beating rate of control group did not change. This study indicated that mi-crogravity affects both the structure and function of myocardial cells. Our results suggest that a 3D heart tissue-equivalent model maybe better for attempting to elucidate the microgravity effects on myocardiocytes in

  6. Fabrication of controlled-release budesonide tablets via desktop (FDM) 3D printing.

    PubMed

    Goyanes, Alvaro; Chang, Hanah; Sedough, Daniel; Hatton, Grace B; Wang, Jie; Buanz, Asma; Gaisford, Simon; Basit, Abdul W

    2015-12-30

    The aim of this work was to explore the feasibility of using fused deposition modelling (FDM) 3D printing (3DP) technology with hot melt extrusion (HME) and fluid bed coating to fabricate modified-release budesonide dosage forms. Budesonide was sucessfully loaded into polyvinyl alcohol filaments using HME. The filaments were engineered into capsule-shaped tablets (caplets) containing 9mg budesonide using a FDM 3D printer; the caplets were then overcoated with a layer of enteric polymer. The final printed formulation was tested in a dynamic dissolution bicarbonate buffer system, and two commercial budesonide products, Cortiment® (Uceris®) and Entocort®, were also investigated for comparison. Budesonide release from the Entocort® formulation was rapid in conditions of the upper small intestine while release from the Cortiment® product was more delayed and very slow. In contrast, the new 3D printed caplet formulation started to release in the mid-small intestine but release then continued in a sustained manner throughout the distal intestine and colon. This work has demonstrated the potential of combining FDM 3DP with established pharmaceutical processes, including HME and film coating, to fabricate modified release oral dosage forms. PMID:26481468

  7. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  8. Large-area fabrication of 3D petal-like nanopattern for surface enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Zhou, Weimin; Wang, Jinhe; Zhang, Jing; Li, Xiaoli; Min, Guoquan

    2014-06-01

    A very easy and flexible approach to fabricate large area, petal-like nanopattern for surface enhanced Raman scattering using soft imprint lithography are presented here. The morphology of the petal-like nanopattern can be transferred truly using the h-PDMS and diluted PMMA molding template. By means of Au metal deposition, a SERS substrate with high enhancement factor over large area, which is still a problem, was produced easily. The morphology and Raman enhancement effect of the 3D nanopattern are characterized by SEM, AFM and SERS. The results show that the petal-like 3D nanopattern has high SERS enhancement factor (order of 1.0 × 108) and could be a promising low cost and high performance SERS active substrate.

  9. Injectable 3-D Fabrication of Medical Electronics at the Target Biological Tissues

    NASA Astrophysics Data System (ADS)

    Jin, Chao; Zhang, Jie; Li, Xiaokang; Yang, Xueyao; Li, Jingjing; Liu, Jing

    2013-12-01

    Conventional transplantable biomedical devices generally request sophisticated surgery which however often causes big trauma and serious pain to the patients. Here, we show an alternative way of directly making three-dimensional (3-D) medical electronics inside the biological body through sequential injections of biocompatible packaging material and liquid metal ink. As the most typical electronics, a variety of medical electrodes with different embedded structures were demonstrated to be easily formed at the target tissues. Conceptual in vitro experiments provide strong evidences for the excellent performances of the injectable electrodes. Further in vivo animal experiments disclosed that the formed electrode could serve as both highly efficient ECG (Electrocardiograph) electrode and stimulator electrode. These findings clarified the unique features and practicability of the liquid metal based injectable 3-D fabrication of medical electronics. The present strategy opens the way for directly manufacturing electrophysiological sensors or therapeutic devices in situ via a truly minimally invasive approach.

  10. Injectable 3-D Fabrication of Medical Electronics at the Target Biological Tissues

    PubMed Central

    Jin, Chao; Zhang, Jie; Li, Xiaokang; Yang, Xueyao; Li, Jingjing; Liu, Jing

    2013-01-01

    Conventional transplantable biomedical devices generally request sophisticated surgery which however often causes big trauma and serious pain to the patients. Here, we show an alternative way of directly making three-dimensional (3-D) medical electronics inside the biological body through sequential injections of biocompatible packaging material and liquid metal ink. As the most typical electronics, a variety of medical electrodes with different embedded structures were demonstrated to be easily formed at the target tissues. Conceptual in vitro experiments provide strong evidences for the excellent performances of the injectable electrodes. Further in vivo animal experiments disclosed that the formed electrode could serve as both highly efficient ECG (Electrocardiograph) electrode and stimulator electrode. These findings clarified the unique features and practicability of the liquid metal based injectable 3-D fabrication of medical electronics. The present strategy opens the way for directly manufacturing electrophysiological sensors or therapeutic devices in situ via a truly minimally invasive approach. PMID:24309385

  11. Design and fabrication of a freeform prism array for 3D microscopy.

    PubMed

    Li, Lei; Yi, Allen Y

    2010-12-01

    Traditional microscopes have limitations in obtaining true 3D (three-dimensional) stereovision. Although some optical microscopes have been developed for 3D vision, many of them are complex, expensive, or limited to transparent samples. In this research, a freeform optical prism array was designed and fabricated to achieve 3D stereo imaging capability for microscope and machine vision applications. To form clear stereo images from multiple directions simultaneously, freeform optical surface design was applied to the prisms. In a ray tracing operation to determine the optical performance of the freeform prisms, Taylor series was used to calculate the surface shape. The virtual image spot diagrams were generated by using ray tracing methods for both the freeform prisms and the regular prisms. The results showed that all the light rays can be traced back to a single point for the freeform prism, and aberration was much smaller than that of the regular prism. The ray spots formed by the freeform prisms were adequate for image formation. Furthermore, the freeform prism array was fabricated by using a combined ultraprecision diamond turning and slow tool servo broaching process in a single, uninterrupted operation. The slow tool servo process ensured that the relative tolerance among prisms is guaranteed by the precision of the ultraprecision machine without the need for assembly. Finally 3D imaging tests were conducted to verify the freeform prism array's optical performance. The principle of the freeform prism array investigated in this research can be applied to microscopy, machine vision, robotic sensing, and many other areas. PMID:21119746

  12. 3D chiral nanoplasmonics: fabrication, chiroptic engineering, mechanism, and application in enantioselection (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Huang, Zhifeng

    2015-09-01

    Chirality does naturally exist, and the building blocks of life (e.g. DNA, proteins, peptides and sugars) are usually chiral. Chirality inherently imposes chemical/biological selectivity on functional molecules; hence the discrimination in molecular chirality from an enantiomer to the other mirror image (i.e. enantioselection) has fundamental and application significance. Enantiomers interact with left and right handed circularly polarized light in a different manner with respect to optical extinction; hence, electronic circular dichroism (ECD) has been widely used for enantioselection. However, enantiomers usually have remarkably low ECD intensity, mainly owing to the small electric transition dipole moment induced by molecular sizes compared to the ECD-active wavelength in the UV-visible-near IR region. To enhance ECD magnitude, recently it has being developed 3D chiral nanoplasmonic structures having a helical path, and the dimensions are comparable to the ECD wavelength. However, it is still ambiguous the origin of 3D chiroplasmonics, and there is a lack of studying the interaction of 3D chiroplasmoncs with enantiomers for the application of enantioselection. Herein, we will present a one-step fabrication of 3D silver nanospirals (AgNSs) via low-substrate-temperature glancing angle deposition. AgNSs can be deposited on a wide range of substrates (including transparent and flexible substrates), in an area on the order of cm2. A set of spiral dimensions (such as spiral pitches, number of turns and handedness) have been easily engineered to tune the chiroptic properties, leading to studying the chiroplasmonic principles together with finite element simulation and the LC model. At the end, it will be demonstrated that 3D chiroplasmonics can differentiate molecular chirality of enantiomers with dramatic enhancement in the anisotropy g factor. This study opens a door to sensitively discriminate enantiomer chirality.

  13. Fabrication and Characterization of 3D Micro- and Nanoelectrodes for Neuron Recordings

    PubMed Central

    Dimaki, Maria; Vazquez, Patricia; Olsen, Mark Holm; Sasso, Luigi; Rodriguez-Trujillo, Romen; Vedarethinam, Indumathi; Svendsen, Winnie E.

    2010-01-01

    In this paper we discuss the fabrication and characterization of three dimensional (3D) micro- and nanoelectrodes with the goal of using them for extra- and intracellular studies. Two different types of electrodes will be described: high aspect ratio microelectrodes for studying the communication between cells and ultimately for brain slice recordings and small nanoelectrodes for highly localized measurements and ultimately for intracellular studies. Electrical and electrochemical characterization of these electrodes as well as the results of PC12 cell differentiation on chip will be presented and discussed. PMID:22163473

  14. Fabrication of 3D polymer photonic crystals for near-IR applications

    NASA Astrophysics Data System (ADS)

    Yao, Peng; Qiu, Liang; Shi, Shouyuan; Schneider, Garrett J.; Prather, Dennis W.; Sharkawy, Ahmed; Kelmelis, Eric

    2008-02-01

    Photonic crystals[1, 2] have stirred enormous research interest and became a growing enterprise in the last 15 years. Generally, PhCs consist of periodic structures that possess periodicity comparable with the wavelength that the PhCs are designed to modulate. If material and periodic pattern are properly selected, PhCs can be applied to many applications based on their unique properties, including photonic band gaps (PBG)[3], self-collimation[4], super prism[5], etc. Strictly speaking, PhCs need to possess periodicity in three dimensions to maximize their advantageous capabilities. However, many current research is based on scaled two-dimensional PhCs, mainly due to the difficulty of fabrication such three-dimensional PhCs. Many approaches have been explored for the fabrication of 3D photonic crystals, including layer-by-layer surface micromachining[6], glancing angle deposition[7], 3D micro-sculpture method[8], self-assembly[9] and lithographical methods[10-12]. Among them, lithographic methods became increasingly accepted due to low costs and precise control over the photonic crystal structure. There are three mostly developed lithographical methods, namely X-ray lithography[10], holographic lithography[11] and two-photon polymerization[12]. Although significant progress has been made in developing these lithography-based technologies, these approaches still suffer from significant disadvantages. X-ray lithography relies on an expensive radiation source. Holographic lithography lacks the flexibility to create engineered defects, and multi-photon polymerization is not suitable for parallel fabrication. In our previous work, we developed a multi-layer photolithography processes[13, 14] that is based on multiple resist application and enhanced absorption upon exposure. Using a negative lift-off resist (LOR) and 254nm DUV source, we have demonstrated fabrication of 3D arbitrary structures with feature size of several microns. However, severe intermixing problem

  15. Size-Controlled Fabrication of Polyaniline Microfibers Based on 3D Hydrodynamic Focusing Approach.

    PubMed

    Yoo, Imsung; Song, Simon; Uh, Kyungchan; Lee, Chan Woo; Kim, Jong-Man

    2015-07-01

    Owing to the relatively high conductivity and unique redox behavior, polyaniline (PANI) has been one of the most technologically promising conducting polymers. Although various methodologies have been developed, fabrication of PANI microfibers has been a challenging task owing to the poor solubility in most organic solvents. By taking advantage of a microfluidic technology and organic soluble acid labile t-Boc-protected PANI (t-Boc-PANI) as the conducting polymer precursor, fabrication of PANI microfibers in a size-controlled manner is possible. Introduction of a THF solution containing t-Boc-PANI, and dodecylbenzenesulfonic acid (DBSA) as a core flow, and water as a sheath flow into a microfluidic channel with a 3D hydrodynamic focusing effect results in crystallization of the polymer fiber. By changing the flow rate, linear PANI microfibers that range from 16.2 to 39.4 μm in diameter are readily obtained. PMID:25882095

  16. Optical 3D Nano-fabrication: Drawing or Growing? (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kawata, Satoshi

    2016-05-01

    Conventional nanotechnology based on the lithography and scanning probe microscopy is limited to 2D fabrication and modification. Here, I will talk about the method for 3D laser fabrication with two-photon polymerization [1], two-photon isomerization [2], and two-photon photo-reduction [3]. Self-growth technology, such as self-grown fiber structures of polymer [4] and self-grown metallic fractal metamaterials structures [5] will be also discussed. [1] S. Kawata, et. al, Nature 412, 697-698, 2001. [2] S. Kawata and Y. Kawata, Chem Rev. 88, 083110, 2006. [3] Y. -Y. Cao, et. al., Small 5, 1144-1148, 2009 [4] S. Shoji and S. Kawata, Appl. Phys. Lett. 75, 737-739, 1999. [5] N. Takeyasu, N. Nishimura, S. Kawata, submitted.

  17. Mass fabrication and delivery of 3D multilayer μTags into living cells

    PubMed Central

    Chen, Lisa Y.; Parizi, Kokab B.; Kosuge, Hisanori; Milaninia, Kaveh M.; McConnell, Michael V.; Wong, H.-S. Philip; Poon, Ada S. Y.

    2013-01-01

    Continuous monitoring of in vivo biological processes and their evolution at the cellular level would enable major advances in our understanding of biology and disease. As a stepping stone towards chronic cellular monitoring, we demonstrate massively parallel fabrication and delivery of 3D multilayer micro-Tags (μTags) into living cells. Both 10 μm × 10 μm × 1.5 μm and 18 μm × 7 μm × 1.5 μm devices containing inductive and capacitive structures were designed and fabricated as potential passive radio-frequency identification tags. We show cellular internalization and persistence of μTags over a 5-day period. Our results represent a promising advance in technologies for studying biology and disease at the cellular level. PMID:23887586

  18. Alginate based 3D hydrogels as an in vitro co-culture model platform for the toxicity screening of new chemical entities

    SciTech Connect

    Lan, Shih-Feng; Starly, Binil

    2011-10-01

    Prediction of human response to potential therapeutic drugs is through conventional methods of in vitro cell culture assays and expensive in vivo animal testing. Alternatives to animal testing require sophisticated in vitro model systems that must replicate in vivo like function for reliable testing applications. Advancements in biomaterials have enabled the development of three-dimensional (3D) cell encapsulated hydrogels as in vitro drug screening tissue model systems. In this study, we have developed an in vitro platform to enable high density 3D culture of liver cells combined with a monolayer growth of target breast cancer cell line (MCF-7) in a static environment as a representative example of screening drug compounds for hepatotoxicity and drug efficacy. Alginate hydrogels encapsulated with serial cell densities of HepG2 cells (10{sup 5}-10{sup 8} cells/ml) are supported by a porous poly-carbonate disc platform and co-cultured with MCF-7 cells within standard cell culture plates during a 3 day study period. The clearance rates of drug transformation by HepG2 cells are measured using a coumarin based pro-drug. The platform was used to test for HepG2 cytotoxicity 50% (CT{sub 50}) using commercially available drugs which further correlated well with published in vivo LD{sub 50} values. The developed test platform allowed us to evaluate drug dose concentrations to predict hepatotoxicity and its effect on the target cells. The in vitro 3D co-culture platform provides a scalable and flexible approach to test multiple-cell types in a hybrid setting within standard cell culture plates which may open up novel 3D in vitro culture techniques to screen new chemical entity compounds. - Graphical abstract: Display Omitted Highlights: > A porous support disc design to support the culture of desired cells in 3D hydrogels. > Demonstrated the co-culture of two cell types within standard cell-culture plates. > A scalable, low cost approach to toxicity screening involving

  19. Fabrication of 2D and 3D Constructs From Reconstituted Decellularized Tissue Extracellular Matrices

    PubMed Central

    Takeda, Yuji S; Xu, Qiaobing

    2016-01-01

    We demonstrated a novel process to reconstitute a decellularized extracellular matrix (Recon-ECM) of heart and liver tissue using a combination of mechanical homogenization and enzymatic digestion. Such Recon-ECM was used as a biomaterial to produce flat or micro-patterned 2D films after crosslinking using replica molding. The mechanical properties of the resulting films were tuned by changing the type of crosslinking reagents. We also demonstrated the fabrication of mechanically robust 3D scaffolds by freeze-drying of the Recon-ECM solution. The porosity of the 3D scaffold was controlled by changing the concentration of the Recon-ECM. HepG2 cells were used to investigate the potential substrate of these engineered 2D patterned and 3D porous structures. The cell attachment, proliferation, and urea synthesis were evaluated, and the results indicate that the scaffold generated from Recon-ECM provides a biologically friendly environment for cells to grow. This method provides a new way to use decellularized ECM as source of biomaterial to produce novel scaffold with better controlled micro- and nano-scale structures, tunable physicochemical properties with desired biological functions. PMID:26000376

  20. Fabrication of computationally designed scaffolds by low temperature 3D printing.

    PubMed

    Castilho, Miguel; Dias, Marta; Gbureck, Uwe; Groll, Jürgen; Fernandes, Paulo; Pires, Inês; Gouveia, Barbara; Rodrigues, Jorge; Vorndran, Elke

    2013-09-01

    The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process. The scaffold design was obtained using a topology optimization approach to maximize the permeability with constraints on the mechanical properties. This procedure was studied to be suitable for the fabrication of a cage prototype for tibial tuberosity advancement application, which is one of the most recent and promising techniques to treat cruciate ligament rupture in dogs. The microstructural and mechanical properties of the scaffolds manufactured by reacting α/β-tricalcium phosphate with diluted phosphoric acid were then assessed experimentally and the scaffolds strength reliability was determined. The results demonstrate that the low temperature 3D printing process is a reliable option to create synthetic scaffolds with tailored properties, and when coupled with topology optimization design it can be a powerful tool for the fabrication of patient-specific bone implants. PMID:23887064

  1. Fabrication of capacitive acoustic resonators combining 3D printing and 2D inkjet printing techniques.

    PubMed

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  2. Design and fabrication of a foldable 3D silicon based package for solid state lighting applications

    NASA Astrophysics Data System (ADS)

    Sokolovskij, R.; Liu, P.; van Zeijl, H. W.; Mimoun, B.; Zhang, G. Q.

    2015-05-01

    Miniaturization of solid state lighting (SSL) luminaires as well as reduction of packaging and assembly costs are of prime interest for the SSL lighting industry. A novel silicon based LED package for lighting applications is presented in this paper. The proposed design consists of 5 rigid Si tiles connected by flexible polyimide hinges with embedded interconnects (ICs). Electrical, optical and thermal characteristics were taken into consideration during design. The fabrication process involved polyimide (PI) application and patterning, aluminium interconnect integration in the flexible hinge, LED reflector cavity formation and metalization followed by through wafer DRIE etching for chip formation and release. A method to connect chip front to backside without TSVs was also integrated into the process. Post-fabrication wafer level assembly included LED mounting and wirebond, phosphor-based colour conversion and silicone encapsulation. The package formation was finalized by vacuum assisted wrapping around an assembly structure to form a 3D geometry, which is beneficial for omnidirectional lighting. Bending tests were performed on the flexible ICs and optical performance at different temperatures was evaluated. It is suggested that 3D packages can be expanded to platforms for miniaturized luminaire applications by combining monolithic silicon integration and system-in-package (SiP) technologies.

  3. Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

    PubMed

    Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

    2014-03-28

    In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions. PMID:24569126

  4. Fabrication of Capacitive Acoustic Resonators Combining 3D Printing and 2D Inkjet Printing Techniques

    PubMed Central

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  5. Increased sensitivity of 3D-Well enzyme-linked immunosorbent assay (ELISA) for infectious disease detection using 3D-printing fabrication technology.

    PubMed

    Singh, Harpal; Shimojima, Masayuki; Fukushi, Shuetsu; Le Van, An; Sugamata, Masami; Yang, Ming

    2015-01-01

    Enzyme-linked Immunosorbent Assay or ELISA -based diagnostics are considered the gold standard in the demonstration of various immunological reaction including in the measurement of antibody response to infectious diseases and to support pathogen identification with application potential in infectious disease outbreaks and individual patients' treatment and clinical care. The rapid prototyping of ELISA-based diagnostics using available 3D printing technologies provides an opportunity for a further exploration of this platform into immunodetection systems. In this study, a '3D-Well' was designed and fabricated using available 3D printing platforms to have an increased surface area of more than 4 times for protein-surface adsorption compared to those of 96-well plates. The ease and rapidity in designing-product development-feedback cycle offered through 3D printing platforms provided an opportunity for its rapid assessment, in which a chemical etching process was used to make the surface hydrophilic followed by validation through the diagnostic performance of ELISA for infectious disease without modifying current laboratory practices for ELISA. The higher sensitivity of the 3D-Well (3-folds higher) compared to the 96-well ELISA provides a potential for the expansion of this technology towards miniaturization platforms to reduce time, volume of reagents and samples needed for laboratory or field diagnosis of infectious diseases including applications in other disciplines. PMID:26406036

  6. Creeping proteins in microporous structures: polymer brush-assisted fabrication of 3D gradients for tissue engineering.

    PubMed

    Gunnewiek, Michel Klein; Di Luca, Andrea; Bollemaat, Hermannes Z; van Blitterswijk, Clemens A; Vancso, G Julius; Moroni, Lorenzo; Benetti, Edmondo M

    2015-06-01

    Coupling of rapid prototyping techniques and surface-confined polymerizations allows the fabrication of 3D multidirectional gradients of biomolecules within microporous scaffolds. The compositional gradients can be tailored by polymer-brush-assisted diffusion of protein solutions. This technique allows spatial control over stem cells manipulation within 3D environments. PMID:25676461

  7. A 3D Porous Gelatin-Alginate-Based-IPN Acts as an Efficient Promoter of Chondrogenesis from Human Adipose-Derived Stem Cells

    PubMed Central

    Jianu, Dana; Tumbar, Tudorita

    2015-01-01

    Cartilage has limited regeneration potential. Thus, there is an imperative need to develop new strategies for cartilage tissue engineering (CTE) amenable for clinical use. Recent CTE approaches rely on optimal cell-scaffold interactions, which require a great deal of optimization. In this study we attempt to build a novel gelatin- (G-) alginate- (A-) polyacrylamide (PAA) 3D interpenetrating network (IPN) with superior performance in promoting chondrogenesis from human adipose-derived stem cells (hADSCs). We show that our G-A-PAA scaffold is capable of supporting hADSCs proliferation and survival, with no apparent cytotoxic effect. Moreover, we find that after exposure to prochondrogenic conditions a key transcription factor known to induce chondrogenesis, namely, Sox9, is highly expressed in our hADSCs/G-A-PAA bioconstruct, along with cartilage specific markers such as collagen type II, CEP68, and COMP extracellular matrix (ECM) components. These data suggest that our G-A-PAA structural properties and formulation might enable hADSCs conversion towards functional chondrocytes. We conclude that our novel G-A-PAA biomatrix is a good candidate for prospective in vivo CTE applications. PMID:26106422

  8. 3D Porous Chitosan-Alginate Scaffolds as an In Vitro Model for Evaluating Nanoparticle-Mediated Tumor Targeting and Gene Delivery to Prostate Cancer.

    PubMed

    Wang, Kui; Kievit, Forrest M; Florczyk, Stephen J; Stephen, Zachary R; Zhang, Miqin

    2015-10-12

    Cationic nanoparticles (NPs) for targeted gene delivery are conventionally evaluated using 2D in vitro cultures. However, this does not translate well to corresponding in vivo studies because of the marked difference in NP behavior in the presence of the tumor microenvironment. In this study, we investigated whether prostate cancer (PCa) cells cultured in three-dimensional (3D) chitosan-alginate (CA) porous scaffolds could model cationic NP-mediated gene targeted delivery to tumors in vitro. We assessed in vitro tumor cell proliferation, formation of tumor spheroids, and expression of marker genes that promote tumor malignancy in CA scaffolds. The efficacy of NP-targeted gene delivery was evaluated in PCa cells in 2D cultures, PCa tumor spheroids grown in CA scaffolds, and PCa tumors in a mouse TRAMP-C2 flank tumor model. PCa cells cultured in CA scaffolds grew into tumor spheroids and displayed characteristics of higher malignancy as compared to those in 2D cultures. Significantly, targeted gene delivery was only observed in cells cultured in CA scaffolds, whereas cells cultured on 2D plates showed no difference in gene delivery between targeted and nontarget control NPs. In vivo NP evaluation confirmed targeted gene delivery, indicating that only CA scaffolds correctly modeled NP-mediated targeted delivery in vivo. These findings suggest that CA scaffolds serve as a better in vitro platform than 2D cultures for evaluation of NP-mediated targeted gene delivery to PCa. PMID:26347946

  9. Aligned 3D human aortic smooth muscle tissue via layer by layer technique inside microchannels with novel combination of collagen and oxidized alginate hydrogel.

    PubMed

    Rayatpisheh, Shahrzad; Poon, Yin Fun; Cao, Ye; Feng, Jie; Chan, Vincent; Chan-Park, Mary B

    2011-08-01

    Tissue engineering of the small diameter blood vessel medial layer has been challenging. Recreation of the circumferentially aligned multilayer smooth muscle tissue has been one of the major technical difficulties. Some research has utilized cyclic stress to align smooth muscle cells (SMCs) but due to the long time conditioning needed, it was not possible to use primary human cells because of expeditious senescence occurred . We demonstrate rapid buildup of a homogeneous relatively thick (30-40 μm) aligned smooth muscle tissue via layer by layer (LBL) technique within microchannels and a soft cell-adhesive hydrogel. Using a microchannelled scaffold with gapped microwalls, two layers of primary human SMCs separated by an interlayer hydrogel were cultured to confluence within the microchannels. The SMCs aligned along the microchannels because of the physically constraining microwalls. A novel double layered gel consisting of a mixture of pristine and oxidized alginate hydrogel coated with collagen was designed to place between each layer of cells, leading to a thicker tissue in a shorter time. The SMCs penetrated the soft thin interlayer hydrogel within 6 days of seeding of the 2nd cell layer so that the entire construct became more or less homogeneously populated by the SMCs. The unique LBL technique applied within the micropatterned scaffold using a soft cell-adhesive gel interlayer allows rapid growth and confluence of SMCs on 2D surface but at the same time aligns the cells and builds up multiple layers into a 3D tissue. This pseudo-3D buildup method avoids the typical steric resistance of hydrogel embedding. PMID:21548018

  10. Characterization of core-shell calcium-alginate macrocapsules fabricated by electro-coextrusion.

    PubMed

    Phawaphuthanon, Natthiya; Behnam, Shabnam; Koo, Song Yi; Pan, Cheol-Ho; Chung, Donghwa

    2014-04-01

    Spherical macrocapsules, where calcium-alginate shell enclosed olive oil as a model core medium, were fabricated by electro-coextrusion. The effects of three key process factors, including alginate concentration in shell fluid (0.5-4.0%), shell-to-core flow rate ratio (4-12 at a fixed core flow rate of 0.05 mL/min), and applied voltage (0-10 kV), on the morphological and textural characteristics of the macrocapsules were analyzed using response surface methodology. The analysis showed that the diameter, shell thickness, hardness, and breaking energy of the macrocapsules were in the ranges of 0.89-1.61 mm, 17.4-66.4 μm, 1.37-11.01 N, and 0.34-6.90 mJ, respectively, and strongly influenced by all the three factors, except that the surface appearance was only significantly affected by the shell-to-core flow rate ratio. The process factors were also optimized for the practically useful macrocapsules, having non-oily surface and hardness larger than 3 N, using a graphical optimization technique. PMID:24463268

  11. Fabrication of digital rainbow holograms and 3-D imaging using SEM based e-beam lithography.

    PubMed

    Firsov, An; Firsov, A; Loechel, B; Erko, A; Svintsov, A; Zaitsev, S

    2014-11-17

    Here we present an approach for creating full-color digital rainbow holograms based on mixing three basic colors. Much like in a color TV with three luminescent points per single screen pixel, each color pixel of initial image is presented by three (R, G, B) distinct diffractive gratings in a hologram structure. Change of either duty cycle or area of the gratings are used to provide proper R, G, B intensities. Special algorithms allow one to design rather complicated 3D images (that might even be replacing each other with hologram rotation). The software developed ("RainBow") provides stability of colorization of rotated image by means of equalizing of angular blur from gratings responsible for R, G, B basic colors. The approach based on R, G, B color synthesis allows one to fabricate gray-tone rainbow hologram containing white color what is hardly possible in traditional dot-matrix technology. Budgetary electron beam lithography based on SEM column was used to fabricate practical examples of digital rainbow hologram. The results of fabrication of large rainbow holograms from design to imprinting are presented. Advantages of the EBL in comparison to traditional optical (dot-matrix) technology is considered. PMID:25402115

  12. Elasto-Capillary Folding Using Stop-Programmable Hinges Fabricated by 3D Micro-Machining

    PubMed Central

    Legrain, Antoine; Berenschot, Erwin J. W.; Tas, Niels R.; Abelmann, Leon

    2015-01-01

    We show elasto-capillary folding of silicon nitride objects with accurate folding angles between flaps of (70.6 ± 0.1)° and demonstrate the feasibility of such accurate micro-assembly with a final folding angle of 90°. The folding angle is defined by stop-programmable hinges that are fabricated starting from silicon molds employing accurate three-dimensional corner lithography. This nano-patterning method exploits the conformal deposition and the subsequent timed isotropic etching of a thin film in a 3D shaped silicon template. The technique leaves a residue of the thin film in sharp concave corners which can be used as an inversion mask in subsequent steps. Hinges designed to stop the folding at 70.6° were fabricated batchwise by machining the V-grooves obtained by KOH etching in (110) silicon wafers; 90° stop-programmable hinges were obtained starting from silicon molds obtained by dry etching on (100) wafers. The presented technique has potential to achieve any folding angle and opens a new route towards creating structures with increased complexity, which will ultimately lead to a novel method for device fabrication. PMID:25992886

  13. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment

    PubMed Central

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  14. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment.

    PubMed

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  15. A simple configuration for fabrication of 2D and 3D photonic quasicrystals with complex structures

    NASA Astrophysics Data System (ADS)

    Sun, XiaoHong; Wang, Shuai; Liu, Wei; Jiang, LiuDi

    2016-06-01

    A simple method using a single-prism common-path interferometer is presented for the fabrication of complex quasicrystals in sub-micrometer scales. Multiple types of two-dimensional (2D) and three-dimensional (3D) quasicrystalline structures are designed and their diffraction patterns are obtained by using Fourier Transform method. Multi-fold rotational symmetries are demonstrated and compared. By using this method, a wide range of quasicrystals types can be produced with arbitrary complexities and rotational symmetries. The transmittance studies of 12-fold and 18-fold structures also reveal the existence of complete photonic bandgaps, which also demonstrates increased symmetry and significantly improved characteristics of photonic band-gaps.

  16. Developing on-machine 3D profile measurement for deterministic fabrication of aspheric mirrors.

    PubMed

    Dong, Zhichao; Cheng, Haobo; Ye, Xu; Tam, Hon-Yuen

    2014-08-01

    Three-dimensional profile measurement is perceived as an indispensable process for deterministic fabrication of aspheric mirrors. In this work, we develop on-machine 3D profile measurement on a subaperture polishing machine, namely, JR-1800. The influences of mechanical errors, misalignments, output stability, temperature variation, and natural vibration are investigated in detail by calibration, mechanical alignment, and finite-element analysis. Two quantitative methods are presented for aligning the turntable, length gauge, and workpiece into together. An error compensation model is also developed for further eliminating misalignments. For feasibility validation, two prototypical workpieces are measured by JR-1800 and an interferometer. The results indicate that JR-1800 has an RMS repeatability of ~λ/30 (λ=632.8  nm). The data provided by the two systems are highly coincident. Direct subtractions of the results from the two systems indicate that the RMS deviations for both segments are less than 0.07 μm. PMID:25090332

  17. Aerosol based direct-write micro-additive fabrication method for sub-mm 3D metal-dielectric structures

    NASA Astrophysics Data System (ADS)

    Rahman, Taibur; Renaud, Luke; Heo, Deuk; Renn, Michael; Panat, Rahul

    2015-10-01

    The fabrication of 3D metal-dielectric structures at sub-mm length scale is highly important in order to realize low-loss passives and GHz wavelength antennas with applications in wearable and Internet-of-Things (IoT) devices. The inherent 2D nature of lithographic processes severely limits the available manufacturing routes to fabricate 3D structures. Further, the lithographic processes are subtractive and require the use of environmentally harmful chemicals. In this letter, we demonstrate an additive manufacturing method to fabricate 3D metal-dielectric structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system at 10-100 µm length scale and instantaneously cured to build complex 3D shapes at a length scale  <1 mm. A metal nanoparticle ink is then dispensed over the 3D dielectric using a combination of jetting action and tilted dispense head, also using the Aerosol Jet technique and at a length scale 10-100 µm, followed by the nanoparticle sintering. Simulation studies are carried out to demonstrate the feasibility of using such structures as mm-wave antennas. The manufacturing method described in this letter opens up the possibility of fabricating an entirely new class of custom-shaped 3D structures at a sub-mm length scale with potential applications in 3D antennas and passives.

  18. Bioactive fish collagen/polycaprolactone composite nanofibrous scaffolds fabricated by electrospinning for 3D cell culture.

    PubMed

    Choi, Da Jeong; Choi, Seung Mi; Kang, Hae Yeong; Min, Hye-Jin; Lee, Rira; Ikram, Muhammad; Subhan, Fazli; Jin, Song Wan; Jeong, Young Hun; Kwak, Jong-Young; Yoon, Sik

    2015-07-10

    One of the most challenging objectives of 3D cell culture is the development of scaffolding materials with outstanding biocompatibility and favorable mechanical strength. In this study, we fabricated a novel nanofibrous scaffold composed of fish collagen (FC) and polycaprolactone (PCL) blends by using the electrospinning method. Nanofibrous scaffolds were characterized using a scanning electron microscope (SEM), and it was revealed that the diameter of nanofibers decreased as FC content was increased in the FC/PCL composite nanofibers. The cytocompatibility of the FC/PCL scaffolds was evaluated by SEM, WST-1 assay, confocal microscopy, western blot, and RT-PCR. It was found that the scaffolds not only facilitated the adhesion, spreading, protrusions, and proliferation of thymic epithelial cells (TECs), but also stimulated the expression of genes and proteins involved in cell adhesion and T-cell development. Thus, these results suggest that the FC/PCL composite nanofibrous scaffolds will be a useful model of 3D cell culture for TECs and may have wide applicability in the future for engineering tissues or organs. PMID:25617682

  19. Bottom-up Fabrication of Multilayer Stacks of 3D Photonic Crystals from Titanium Dioxide.

    PubMed

    Kubrin, Roman; Pasquarelli, Robert M; Waleczek, Martin; Lee, Hooi Sing; Zierold, Robert; do Rosário, Jefferson J; Dyachenko, Pavel N; Montero Moreno, Josep M; Petrov, Alexander Yu; Janssen, Rolf; Eich, Manfred; Nielsch, Kornelius; Schneider, Gerold A

    2016-04-27

    A strategy for stacking multiple ceramic 3D photonic crystals is developed. Periodically structured porous films are produced by vertical convective self-assembly of polystyrene (PS) microspheres. After infiltration of the opaline templates by atomic layer deposition (ALD) of titania and thermal decomposition of the polystyrene matrix, a ceramic 3D photonic crystal is formed. Further layers with different sizes of pores are deposited subsequently by repetition of the process. The influence of process parameters on morphology and photonic properties of double and triple stacks is systematically studied. Prolonged contact of amorphous titania films with warm water during self-assembly of the successive templates is found to result in exaggerated roughness of the surfaces re-exposed to ALD. Random scattering on rough internal surfaces disrupts ballistic transport of incident photons into deeper layers of the multistacks. Substantially smoother interfaces are obtained by calcination of the structure after each infiltration, which converts amorphous titania into the crystalline anatase before resuming the ALD infiltration. High quality triple stacks consisting of anatase inverse opals with different pore sizes are demonstrated for the first time. The elaborated fabrication method shows promise for various applications demanding broadband dielectric reflectors or titania photonic crystals with a long mean free path of photons. PMID:27045887

  20. Fabrication of 3-D Reconstituted Organoid Arrays by DNA-Programmed Assembly of Cells (DPAC).

    PubMed

    Todhunter, Michael E; Weber, Robert J; Farlow, Justin; Jee, Noel Y; Cerchiari, Alec E; Gartner, Zev J

    2016-01-01

    Tissues are the organizational units of function in metazoan organisms. Tissues comprise an assortment of cellular building blocks, soluble factors, and extracellular matrix (ECM) composed into specific three-dimensional (3-D) structures. The capacity to reconstitute tissues in vitro with the structural complexity observed in vivo is key to understanding processes such as morphogenesis, homeostasis, and disease. In this article, we describe DNA-programmed assembly of cells (DPAC), a method to fabricate viable, functional arrays of organoid-like tissues within 3-D ECM gels. In DPAC, dissociated cells are chemically functionalized with degradable oligonucleotide "Velcro," allowing rapid, specific, and reversible cell adhesion to a two-dimensional (2-D) template patterned with complementary DNA. An iterative assembly process builds up organoids, layer-by-layer, from this initial 2-D template and into the third dimension. Cleavage of the DNA releases the completed array of tissues that are captured and fully embedded in ECM gels for culture and observation. DPAC controls the size, shape, composition, and spatial heterogeneity of organoids and permits positioning of constituent cells with single-cell resolution even within cultures several centimeters long. © 2016 by John Wiley & Sons, Inc. PMID:27622567

  1. In-vivo behavior of Si-hydroxyapatite/polycaprolactone/DMB scaffolds fabricated by 3D printing.

    PubMed

    Meseguer-Olmo, Luis; Vicente-Ortega, Vicente; Alcaraz-Baños, Miguel; Calvo-Guirado, José Luis; Vallet-Regí, María; Arcos, Daniel; Baeza, Alejandro

    2013-07-01

    Scaffolds made of polycaprolactone and nanocrystalline silicon-substituted hydroxyapatite have been fabricated by 3D printing rapid prototyping technique. To asses that the scaffolds fulfill the requirements to be considered for bone grafting applications, they were implanted in New Zealand rabbits. Histological and radiological studies have demonstrated that the scaffolds implanted in bone exhibited an excellent osteointegration without the interposition of fibrous tissue between bone and implants and without immune response after 4 months of implantation. In addition, we have evaluated the possibility of improving the scaffolds efficiency by incorporating demineralized bone matrix during the preparation by 3D printing. When demineralized bone matrix (DBM) is incorporated, the efficacy of the scaffolds is enhanced, as new bone formation occurs not only in the peripheral portions of the scaffolds but also within its pores after 4 months of implantation. This enhanced performance can be explained in terms of the osteoinductive properties of the DBM in the scaffolds, which have been assessed through the new bone tissue formation when the scaffolds are ectopically implanted. PMID:23255259

  2. 3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

    NASA Astrophysics Data System (ADS)

    Deffenbaugh, Paul Issac

    3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

  3. Fabrication and characterization of nanoclay modified PMR type polyimide composites reinforced with 3D woven basalt fabric

    NASA Astrophysics Data System (ADS)

    Xie, Jianfei; Qiu, Yiping

    2009-07-01

    Nanoclay modified PMR type polyimide composites were prepared from 3D orthogonal woven basalt fiber performs and nanoclay modified polyimide matrix resin, which derived from methylene dianiline (MDA), dimethyl ester of 3,3',4,4'- oxydiphthalic acid (ODPE), monomethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (NE) and nanoclay. The Na+-montmorillonite was organically treated using a 1:1 molar ratio mixture of dodecylamine (C12) and MDA. The rheological properties of neat B-stage PMR polyimide and 2% clay modified B-stage PMR polyimide were investigated. Based on the results obtained from the rheological tests, a two step compression molding process can be established for the composites. In the first step, the 3D fabric preforms were impregnated with polyimide resin in a vacuum oven and heated up for degassing the volatiles and by-products. In the second step, composites were compressed. The internal structure of the composites was observed by a microscope. Incorporation of 2% clay showed an improvement in the Tg and stiffness of the PMR polyimide. The resulting composites exhibited high thermal stability and good mechanical properties.

  4. Femtosecond laser 3D fabrication of whispering-gallery-mode microcavities

    NASA Astrophysics Data System (ADS)

    Xu, HuaiLiang; Sun, HongBo

    2015-11-01

    Whispering-gallery-mode (WGM) microcavities with high-quality factors and small volumes have attracted intense interests in the past decades because of their potential applications in various research fields such as quantum information, sensing, and optoelectronics. This leads to rapid advance in a variety of processing technologies that can create high-quality WGM micro- cavities. Due to the unique characteristics of femtosecond laser pulses with high peak intensity and ultrashort pulse duration, femtosecond laser shows the ability to carry out ultrahigh precision micromachining of a variety of transparent materials through nonlinear multiphoton absorption and tunneling ionization. This review paper describes the basic principle of femtosecond laser direct writing, and presents an overview of recent progress concerning femtosecond laser three-dimensional (3D) fabrications of optical WGM microcavities, which include the advances in the fabrications of passive and active WGMs microcavities in a variety of materials such as polymer, glass and crystals, as well as in processing the integrated WGM-microcavity device. Lastly, a summary of this dynamic field with a future perspective is given.

  5. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds.

    PubMed

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol, Jon; Szabo, Peter; Burri, Harsha Vardhan Reddy; Canali, Chiara; Dufva, Marin; Emnéus, Jenny; Wolff, Anders

    2015-10-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm(2)/cm(3) surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm(3) scaffold with about 16,000 interconnected channels (about 1m(2) surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6×4 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive. PMID:26117791

  6. EFAB: low-cost automated electrochemical batch fabrication of arbitrary 3D microstructures

    NASA Astrophysics Data System (ADS)

    Cohen, Adam L.; Frodis, Uri; Tseng, Fan-Gang; Zhang, Gang; Mansfeld, Florian; Will, Peter M.

    1999-08-01

    EFAB is a new micromachining process promising to rapidly and automatically batch fabricate high-aspect-ratio microstructures with arbitrary 3D geometry using inexpensive equipment. Conventional microfabrication processes have so far produced fairly simple geometries, yet many MEMS could benefit if more sophisticated shapes could be manufactured. By using 'Instant Masking' (IM) - a novel in-situ micropatterning method - to simplify, accelerate, and automate through-mask electroplating, EFAB can produce extremely complex shapes by depositing hundreds-thousands of layers at high speed. While other processes of the do not allow integration with ICs, EFAB operates at less than 60 degrees C, making IC compatibility a possibility. Alternative processes require costly facilities and equipment; EFAB separates photolithography from device fabrication, requiring a cleanroom only for mask-making, then depositing all layers in a low-cost, self-contained machine. All IM required can be prepared simultaneously, without repeating the lithography on each layer. Selective electrodeposition requires simply mating the mask with the substrate and applying current; in this way we have patterned well-defined features as small as 20 X 20 micrometers . The procedures in EFAB are selective electrodeposition, blanket electrodeposition, and planarization. To date we have built metal structures with up to 12 layers consisting of independently-moving components.

  7. 3D ordered nanostructures fabricated by nanosphere lithography using an organometallic etch mask

    NASA Astrophysics Data System (ADS)

    Ling, Xing Yi; Acikgoz, Canet; Phang, In Yee; Hempenius, Mark A.; Reinhoudt, David N.; Vancso, G. Julius; Huskens, Jurriaan

    2010-08-01

    A new approach for fabricating porous structures on silicon substrates and on polymer surfaces, using colloidal particle arrays with a polymer mask of a highly etch-resistant organometallic polymer, is demonstrated. Monolayers of silica particles, with diameters of 60 nm, 150 nm, 300 nm, or 500 nm, were deposited either on a silicon substrate or on a surface coated with polyethersulfone (PES), and the voids of the arrays were filled with poly(ferrocenylmethylphenylsilane) (PFMPS). Argon ion sputtering removed the excess PFMPS on the particles which enabled removal of the particles with HF. Further pattern transfer steps with reactive ion etching for different time intervals provided structures in silicon or in a PES layer. Free-standing PES membranes exhibiting regular arrays of circular holes with high porosity were fabricated by using cellulose acetate as a sacrificial layer. The pores obtained on silicon substrates after etching were used as molds for nanoimprint lithography (NIL). A combination of the techniques of nanosphere lithography (NSL) and NIL has resulted in 3D nanostructures with a hemispherical shape (inherited from the nanoparticles) which was obtained both in silicon and in PMMA.

  8. Cast and 3D printed ion exchange membranes for monolithic microbial fuel cell fabrication

    NASA Astrophysics Data System (ADS)

    Philamore, Hemma; Rossiter, Jonathan; Walters, Peter; Winfield, Jonathan; Ieropoulos, Ioannis

    2015-09-01

    We present novel solutions to a key challenge in microbial fuel cell (MFC) technology; greater power density through increased relative surface area of the ion exchange membrane that separates the anode and cathode electrodes. The first use of a 3D printed polymer and a cast latex membrane are compared to a conventionally used cation exchange membrane. These new techniques significantly expand the geometric versatility available to ion exchange membranes in MFCs, which may be instrumental in answering challenges in the design of MFCs including miniaturisation, cost and ease of fabrication. Under electrical load conditions selected for optimal power transfer, peak power production (mean 10 batch feeds) was 11.39 μW (CEM), 10.51 μW (latex) and 0.92 μW (Tangoplus). Change in conductivity and pH of anolyte were correlated with MFC power production. Digital and environmental scanning electron microscopy show structural changes to and biological precipitation on membrane materials following long term use in an MFC. The cost of the novel membranes was lower than the conventional CEM. The efficacy of two novel membranes for ion exchange indicates that further characterisation of these materials and their fabrication techniques, shows great potential to significantly increase the range and type of MFCs that can be produced.

  9. New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

    PubMed

    Light, Edward D; Lieu, Victor; Smith, Stephen W

    2009-10-01

    We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication of large numbers of devices. We developed two new fabrication methods that we believe can be used to efficiently manufacture these types of devices in greater than prototype numbers. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter of a Cook Medical, Inc. inferior vena cava (IVC) filter deployment device. We used a braided wiring technology from Tyco Electronics Corp. to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz and the 50 Omega round trip insertion loss was --82 dB. The mean of the nearest neighbor cross talk was -37.0 dB. The second method consisted of a 46-cm long single layer flex circuit from MicroConnex that terminates in an interconnect that plugs directly into our system cable. This transducer had 70 elements at 0.157 mm interelement spacing operating at 4.8 MHz. Typical measured transducer element bandwidth was 29% and the 50 Omega round trip insertion loss was -83 dB. The mean of the nearest neighbor cross talk was -33.0 dB. PMID:20458877

  10. Fabrication, densification, and replica molding of 3D carbon nanotube microstructures.

    PubMed

    Copic, Davor; Park, Sei Jin; Tawfick, Sameh; De Volder, Michael; Hart, A John

    2012-01-01

    The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques (1, 2), and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT

  11. Novel 3D modeling methods for virtual fabrication and EDA compatible design of MEMS via parametric libraries

    NASA Astrophysics Data System (ADS)

    Schröpfer, Gerold; Lorenz, Gunar; Rouvillois, Stéphane; Breit, Stephen

    2010-06-01

    This paper provides a brief summary of the state-of-the-art of MEMS-specific modeling techniques and describes the validation of new models for a parametric component library. Two recently developed 3D modeling tools are described in more detail. The first one captures a methodology for designing MEMS devices and simulating them together with integrated electronics within a standard electronic design automation (EDA) environment. The MEMS designer can construct the MEMS model directly in a 3D view. The resulting 3D model differs from a typical feature-based 3D CAD modeling tool in that there is an underlying behavioral model and parametric layout associated with each MEMS component. The model of the complete MEMS device that is shared with the standard EDA environment can be fully parameterized with respect to manufacturing- and design-dependent variables. Another recent innovation is a process modeling tool that allows accurate and highly realistic visualization of the step-by-step creation of 3D micro-fabricated devices. The novelty of the tool lies in its use of voxels (3D pixels) rather than conventional 3D CAD techniques to represent the 3D geometry. Case studies for experimental devices are presented showing how the examination of these virtual prototypes can reveal design errors before mask tape out, support process development before actual fabrication and also enable failure analysis after manufacturing.

  12. In Situ Fabrication of 3D Ag@ZnO Nanostructures for Microfluidic Surface-Enhanced Raman Scattering Systems

    PubMed Central

    2015-01-01

    In this work, we develop an in situ method to grow highly controllable, sensitive, three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrates via an optothermal effect within microfluidic devices. Implementing this approach, we fabricate SERS substrates composed of Ag@ZnO structures at prescribed locations inside microfluidic channels, sites within which current fabrication of SERS structures has been arduous. Conveniently, properties of the 3D Ag@ZnO nanostructures such as length, packing density, and coverage can also be adjusted by tuning laser irradiation parameters. After exploring the fabrication of the 3D nanostructures, we demonstrate a SERS enhancement factor of up to ∼2 × 106 and investigate the optical properties of the 3D Ag@ZnO structures through finite-difference time-domain simulations. To illustrate the potential value of our technique, low concentrations of biomolecules in the liquid state are detected. Moreover, an integrated cell-trapping function of the 3D Ag@ZnO structures records the surface chemical fingerprint of a living cell. Overall, our optothermal-effect-based fabrication technique offers an effective combination of microfluidics with SERS, resolving problems associated with the fabrication of SERS substrates in microfluidic channels. With its advantages in functionality, simplicity, and sensitivity, the microfluidic-SERS platform presented should be valuable in many biological, biochemical, and biomedical applications. PMID:25402207

  13. Combination of thermal extrusion printing and ultrafast laser fabrication for the manufacturing of 3D composite scaffolds

    NASA Astrophysics Data System (ADS)

    Balčiūnas, Evaldas; Lukoševičius, Laurynas; Mackevičiūtė, Dovilė; Rekštytė, Sima; Rutkūnas, Vygandas; Paipulas, Domas; Stankevičiūtė, Karolina; Baltriukienė, Daiva; Bukelskienė, Virginija; Piskarskas, Algis P.; Malinauskas, Mangirdas

    2014-03-01

    We present a novel approach to manufacturing 3D microstructured composite scaffolds for tissue engineering applications. A thermal extrusion 3D printer - a simple, low-cost tabletop device enabling rapid materialization of CAD models in plastics - was used to produce cm-scale microporous scaffolds out of polylactic acid (PLA). The fabricated objects were subsequently immersed in a photosensitive monomer solution and direct laser writing technique (DLW) was used to refine its inner structure by fabricating a fine mesh inside the previously produced scaffold. In addition, a composite material structure out of four different materials fabricated via DLW is presented. This technique, empowered by ultrafast lasers allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. A composite scaffold made of distinct materials and periodicities is acquired after the development process used to wash out non-linked monomers. Another way to modify the 3D printed PLA surfaces was also demonstrated - ablation with femtosecond laser beam. Structure geometry on macro- to micro- scales could be finely tuned by combining these fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. To our best knowledge, this is the first experimental demonstration showing the creation of composite 3D scaffolds using convenient 3D printing combined with DLW. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro-featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of tissue engineering, as well as in microelectromechanical systems, microfluidics, microoptics and others.

  14. Fabrication of 3D Scaffolds with Nano-Hydroxyapatite for Improving the Preosteoblast Cell-Biological Performance.

    PubMed

    Roh, Hee-Sang; Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-08-01

    Three-dimensional (3D) scaffolds fabricated by rapid prototyping techniques have many merits for tissue engineering applications, due to its controllable properties such as porosity, pore size and structural shape. Nonetheless, low cell seeding efficiency remains drawback. In this study, poly-caprolactone (PCL) composite 3D extruded scaffolds were modified with nano hydroxyapatite (n-HAp). PCL/n-HAp 3D scaffold surface was treated with oxygen plasma to improve the preosteoblast cell seeding efficiency and proliferation. The results indicate that oxygen plasma is useful technique to improve the cell affinity. PMID:26369121

  15. 3D polycarprolactone (PCL) scaffold with hierarchical structure fabricated by a piezoelectric transducer (PZT)-assisted bioplotter

    NASA Astrophysics Data System (ADS)

    Kim, Geun Hyung; Son, Joon Gon

    2009-03-01

    The 3D bioplotter, which is one of the rapid-prototyping systems, enables us to produce the design-based scaffolds which could control good mechanical properties and pore structures for mimicking human organs. Although the plotting system has several advantages to fabricate a variety of designed scaffolds, the main disadvantage of scaffolds fabricated by the system is that the strand surfaces are too smooth and tend to discourage initial cell attachment within the scaffolds. To overcome the problem, we suggest a new 3D plotting method supplemented by piezoelectric vibration system for fabricating scaffolds that have hierarchical surface structures, which increase the surface roughness of the scaffold without any additional chemical process. The surface-modified 3D scaffold exhibited various positive qualities including enhanced compressive modulus and improved initial cell attachment and proliferation. Cell culturing results demonstrated that the interactions between chondrocytes and the scaffold were much more favorable than those between the cells and conventionally plotted 3D scaffolds. This process provides a feasible new technique for fabricating high-quality 3D scaffolds for tissue engineering applications.

  16. Characterization, fabrication, and analysis of soft dielectric elastomer actuators capable of complex 3D deformation

    NASA Astrophysics Data System (ADS)

    Lai, William

    Inspired by nature, the development of soft actuators has drawn large attention to provide higher flexibility and allow adaptation to more complex environment. This thesis is focused on utilizing electroactive polymers as active materials to develop soft planar dielectric elastomer actuators capable of complex 3D deformation. The potential applications of such soft actuators are in flexible robotic arms and grippers, morphing structures and flapping wings for micro aerial vehicles. The embraces design for a freestanding actuator utilizes the constrained deformation imposed by surface stiffeners on an electroactive membrane to avert the requirement of membrane pre-stretch and the supporting frames. The proposed design increases the overall actuator flexibility and degrees-of-freedom. Actuator design, fabrication, and performance are presented for different arrangement of stiffeners. Digital images correlation technique were utilized to evaluate the in-plane finite strain components, in order to elucidate the role of the stiffeners in controlling the three dimensional deformation. It was found that a key controlling factor was the localized deformation near the stiffeners, while the rest of the membrane would follow through. A detailed finite element modeling framework was developed with a user-material subroutine, built into the ABAQUS commercial finite element package. An experimentally calibrated Neo-Hookean based material model that coupled the applied electrical field to the actuator mechanical deformation was employed. The numerical model was used to optimize different geometrical features, electrode layup and stacking sequence of actuators. It was found that by splitting the stiffeners into finer segments, the force-stroke characteristics of actuator were able to be adjusted with stiffener configuration, while keeping the overall bending stiffness. The efficacy of actuators could also be greatly improved by increasing the stiffener periodicity. The developed

  17. Fabrication of 3D fractal structures using nanoscale anisotropic etching of single crystalline silicon

    NASA Astrophysics Data System (ADS)

    Berenschot, Erwin J. W.; Jansen, Henri V.; Tas, Niels R.

    2013-05-01

    When it comes to high-performance filtration, separation, sunlight collection, surface charge storage or catalysis, the effective surface area is what counts. Highly regular fractal structures seem to be the perfect candidates, but manufacturing can be quite cumbersome. Here it is shown--for the first time—that complex 3D fractals can be engineered using a recursive operation in conventional micromachining of single crystalline silicon. The procedure uses the built-in capability of the crystal lattice to form self-similar octahedral structures with minimal interference of the constructor. The silicon fractal can be used directly or as a mold to transfer the shape into another material. Moreover, they can be dense, porous, or like a wireframe. We demonstrate, after four levels of processing, that the initial number of octahedral structures is increased by a factor of 625. Meanwhile the size decreases 16 times down to 300 nm. At any level, pores of less than 100 nm can be fabricated at the octahedral vertices of the fractal. The presented technique supports the design of fractals with Hausdorff dimension D free of choice and up to D = 2.322.

  18. Monolithic transparent 3D dielectrophoretic micro-actuator fabricated by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Bellouard, Yves

    2015-10-01

    We demonstrate a three-dimensional (3D) monolithic micro-actuator fabricated by non-ablative femtosecond laser micromachining and subsequent chemical etching. The actuating principle is based on dielectrophoresis. An analytical modeling of this actuation scheme is conducted, which is capable of performance prediction, parameter optimization and instability analysis. Static and dynamic characterizations are experimentally verified. An actuation range of 30 μm is well attainable; resonances are captured with an evaluated quality factor of 40 (measured in air) and a bandwidth of 5 Hz for the primary vertical resonance of 200 Hz. A settling time of 200 ms in transient response indicates the damping properties of such actuation scheme. This actuation principle suppresses the need for electrodes on the mobile, non-conductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of the manufacturing process, it can be coupled to other functionalities within monolithic transparent micro-electro-mechanical systems (MEMS) for applications like tunable optical couplers.

  19. Fabrication and characterization of metal-to-metal interconnect structures for 3-D integration

    NASA Astrophysics Data System (ADS)

    Huffman, Alan; Lannon, John; Lueck, Matthew; Gregory, Christopher; Temple, Dorota

    2009-03-01

    The use of collapsible (solder) bump interconnects in pixel detector hybridization has been shown to be very successful. However, as pixel sizes decrease, the use of non-collapsible metal-to-metal bump bonding methods is needed to push the interconnect dimensions smaller. Furthermore, these interconnects are compatible with 3D intgration technologies which are being considered to increase overall pixel and system performance. These metal-to-metal bonding structures provide robust mechanical and electrical connections and allow for a dramatic increase in pixel density. Of particular interest are Cu-Cu thermocompression bonding and Cu/Sn-Cu solid-liquid diffusion bonding processes. Working with Fermilab, RTI undertook a demonstration to show that these bump structures could be reliably used to interconnect devices designed with 20 micron I/O pitch. Cu and Cu/Sn bump fabrication processes were developed to provide a well-controlled surface topography necessary for the formation of low resistance, high yielding, and reliable interconnects. The electrical resistance and yield has been quantified based on electrical measurements of daisy chain test structures and the mechanical strength of the bonding has been quantified through die shear testing. The reliability has been characterized through studies of the impact of thermal exposure on the mechanical performance of the bonds. Cross-section SEM analysis, coupled with high resolution energy dispersive spectroscopy, has provided insight into the physical and chemical nature of the bonding interfaces and aided in the evaluation of the long-term stability of the bonds.

  20. Development of the flow behavior model for 3D scaffold fabrication in the polymer deposition process by a heating method

    NASA Astrophysics Data System (ADS)

    Kim, Jong Young; Park, Jung Kyu; Hahn, Sei Kwang; Kwon, Tai Hun; Cho, Dong-Woo

    2009-10-01

    The flow behavior model for 3D scaffold fabrication in the polymer deposition process by the heating method was developed for enhanced efficiency of the deposition process. The analysis of the polymer flow property is very important in the fabrication process of precise micro-structures such as scaffolds. In this study, a deposition model considering fluid mechanics and heat transfer phenomena was built up and introduced for the estimation of the fluid behavior of molten polymer. The effectiveness of the simulation model was verified through comparison with the experimental result in the case of PCL biomaterial. In addition, the effects of various parameters, such as pressure, temperature and nozzle size, were predicted through simulation before experimental approaches. Through the fabrication of 3D scaffold, it is concluded that this model is useful in predicting the flow behavior characteristics in the micro-structure fabrication process, which is based on the heating method.

  1. Design, simulation, fabrication, and preliminary tests of 3D CMS pixel detectors for the super-LHC

    SciTech Connect

    Koybasi, Ozhan; Bortoletto, Daniela; Hansen, Thor-Erik; Kok, Angela; Hansen, Trond Andreas; Lietaer, Nicolas; Jensen, Geir Uri; Summanwar, Anand; Bolla, Gino; Kwan, Simon Wing Lok; /Fermilab

    2010-01-01

    The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D detector designs with CMS pixel readout electronics are being developed and evaluated for their advantages and drawbacks. The fabrication of full-3D active edge CMS pixel devices with p-type substrate has been successfully completed at SINTEF. In this paper, we study the expected post-irradiation behaviors of these devices with simulations and, after a brief description of their fabrication, we report the first leakage current measurement results as performed on wafer.

  2. Novel carbon-fiber microelectrode batch fabrication using a 3D-printed mold and polyimide resin.

    PubMed

    Trikantzopoulos, Elefterios; Yang, Cheng; Ganesana, Mallikarjunarao; Wang, Ying; Venton, B Jill

    2016-09-21

    Glass insulated carbon-fiber microelectrodes (CFMEs) are standard tools for the measurement of neurotransmitters. However, electrodes are fabricated individually and the glass can shatter, limiting application in higher order mammals. Here, we developed a novel microelectrode batch fabrication method using a 3D-printed mold and polyimide resin insulating agent. The 3D-printed mold is low cost, customizable to change the electrode shape, and allows 40 electrodes to be made simultaneously. The polyimide resin is biocompatible, quick to cure, and does not adhere to the plastic mold. The electrodes were tested for the response to dopamine with fast-scan cyclic voltammetry both in vitro and in vivo and performed similarly to traditional glass-insulated electrodes, but with lower background currents. Thus, polyimide-insulated electrodes can be mass-produced using a 3D-printed mold and are an attractive alternative for making cheap, biocompatible microelectrodes. PMID:27536741

  3. Fabrication of continuous flow microfluidics device with 3D electrode structures for high throughput DEP applications using mechanical machining.

    PubMed

    Zeinali, Soheila; Çetin, Barbaros; Oliaei, Samad Nadimi Bavil; Karpat, Yiğit

    2015-07-01

    Microfluidics is the combination of micro/nano fabrication techniques with fluid flow at microscale to pursue powerful techniques in controlling and manipulating chemical and biological processes. Sorting and separation of bio-particles are highly considered in diagnostics and biological analyses. Dielectrophoresis (DEP) has offered unique advantages for microfluidic devices. In DEP devices, asymmetric pair of planar electrodes could be employed to generate non-uniform electric fields. In DEP applications, facing 3D sidewall electrodes is considered to be one of the key solutions to increase device throughput due to the generated homogeneous electric fields along the height of microchannels. Despite the advantages, fabrication of 3D vertical electrodes requires a considerable challenge. In this study, two alternative fabrication techniques have been proposed for the fabrication of a microfluidic device with 3D sidewall electrodes. In the first method, both the mold and the electrodes are fabricated using high precision machining. In the second method, the mold with tilted sidewalls is fabricated using high precision machining and the electrodes are deposited on the sidewall using sputtering together with a shadow mask fabricated by electric discharge machining. Both fabrication processes are assessed as highly repeatable and robust. Moreover, the two methods are found to be complementary with respect to the channel height. Only the manipulation of particles with negative-DEP is demonstrated in the experiments, and the throughput values up to 105 particles / min is reached in a continuous flow. The experimental results are compared with the simulation results and the limitations on the fabrication techniques are also discussed. PMID:25808433

  4. [EVALUATION OF CHANGES OF GEOMETRICAL PARAMETERS OF ALGINATE DENTAL IMPRESSIONS DUE TO THE INFLUENCE OF CHEMICAL AND MICROWAVE DISINFECTION METHOD USING 3D TECHNOLOGIES].

    PubMed

    Nespraydko, V P; Shevchuk, V A; Michaylov, A A; Lyseyko, N V

    2015-01-01

    This clinical and laboratory study evaluated the effect of two methods of disinfection in different modes at the volume changes of alginate dental impressions and plaster models poured from them, as compared to the same parameters of plastic master models (PMM), using three-dimensional non-contact laser scanner and software. Immersion chemical disinfection for 15 min, microwave disinfection at 354 W for 10 minutes and combined disinfection with the power of 319 W for 4 minutes did not significantly affect the volumetric dimensional accuracy of the alginate impressions (P > 0.05). PMID:27491163

  5. FOREWORD: Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties

    NASA Astrophysics Data System (ADS)

    Yamada, Shooji; Yamaguchi, Hiroshi; Ishihara, Sunao

    2009-06-01

    Microelectromechanical systems (MEMS) are widely used small electromechanical systems made of micrometre-sized components. Presently, we are witnessing a transition from MEMS to nanoelectromechanical systems (NEMS), which comprise devices integrating electrical and mechanical functionality on the nanoscale and offer new exciting applications. Similarly to MEMS, NEMS typically include a central transistor-like nanoelectronic unit for data processing, as well as mechanical actuators, pumps, and motors; and they may combine with physical, biological and chemical sensors. In the transition from MEMS to NEMS, component sizes need to be reduced. Therefore, many fabrication methods previously developed for MEMS are unsuitable for the production of high-precision NEMS components. The key challenge in NEMS is therefore the development of new methods for routine and reproducible nanofabrication. Two complementary types of method for NEMS fabrication are available: 'top-down' and 'bottom-up'. The top-down approach uses traditional lithography technologies, whereas bottom-up techniques include molecular self-organization, self-assembly and nanodeposition. The NT2008 conference, held at Ishikawa High-Tech Conference Center, Ishikawa, Japan, between 23-25 October 2008, focused on novel NEMS fabricated from new materials and on process technologies. The topics included compound semiconductors, small mechanical structures, nanostructures for micro-fluid and bio-sensors, bio-hybrid micro-machines, as well as their design and simulation. This focus issue compiles seven articles selected from 13 submitted manuscripts. The articles by Prinz et al and Kehrbusch et al introduce the frontiers of the top-down production of various operational NEMS devices, and Kometani et al present an example of the bottom-up approach, namely ion-beam induced deposition of MEMS and NEMS. The remaining articles report novel technologies for biological sensors. Taira et al have used manganese nanoparticles

  6. Fabrication, Characterization, And Deformation of 3D Structural Meta-Materials

    NASA Astrophysics Data System (ADS)

    Montemayor, Lauren C.

    Current technological advances in fabrication methods have provided pathways to creating architected structural meta-materials similar to those found in natural organisms that are structurally robust and lightweight, such as diatoms. Structural meta-materials are materials with mechanical properties that are determined by material properties at various length scales, which range from the material microstructure (nm) to the macro-scale architecture (mum -- mm). It is now possible to exploit material size effect, which emerge at the nanometer length scale, as well as structural effects to tune the material properties and failure mechanisms of small-scale cellular solids, such as nanolattices. This work demonstrates the fabrication and mechanical properties of 3-dimensional hollow nanolattices in both tension and compression. Hollow gold nanolattices loaded in uniaxial compression demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. Structural effects were explored by increasing the unit cell angle from 30° to 60° while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200nm to 635nm, at a constant relative density and grain size. In-situ uniaxial compression experiments reveal an order-of-magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of 3-dimensional architected meta-materials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics. This work also explores the flaw tolerance of 3D hollow-tube alumina kagome nanolattices with and without pre-fabricated notches, both in experiment and simulation

  7. Fabrication of 3D tissue equivalent: an in vitro platform for understanding collagen evolution in healthy and diseased models

    NASA Astrophysics Data System (ADS)

    Urciuolo, F.; Imparato, G.; Casale, C.; Scamardella, S.; Netti, P.

    2013-04-01

    In this study we realized a three-dimensional human dermis equivalent (3D-HDE) and, by exploiting multi-photon microscopy (MPM) we validated its use as an in vitro model to study collagen network re-arrangement under simulated solar exposure. The realization of 3D-HDE has been pursed by means of a bottom-up tissue engineering strategy that comprises firstly the fabrication of micron sized tissue building blocks and then their assembly in a 3D tissue construct. The building blocks injected in a maturation chamber, and cultured under optimized culture condition, were able to fuse due to the establishment of cell-cell and cell-extra cellular matrix (ECM) interactions that induced a biological sintering process resulting in 3D-HDE production. The final 3D tissue was made-up by fibroblasts embedded in their own ECM rich in endogenous collagen type I, resembling the composition and the architecture of native human dermis. Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (TPEF) imaging have been exploited to assess modification in collagen assembly before and after UV irradiation. Textural features and SHG to TPFE ratio of the endogenous ECM within 3D-HDE have been shown to vary after UVA irradiation, proving the hypothesis that the 3DHDE realized can be used as biological platform in vitro to study ECM modifications induced by photo-damage.

  8. Hot embossing for fabrication of a microfluidic 3D cell culture platform

    PubMed Central

    Jeon, Jessie S.; Chung, Seok; Kamm, Roger D.; Charest, Joseph L.

    2011-01-01

    Clinically relevant studies of cell function in vitro require a physiologically-representative microenvironment possessing aspects such as a 3D extracellular matrix (ECM) and controlled biochemical and biophysical parameters. A polydimethylsiloxane (PDMS) microfluidic system with a 3D collagen gel has previously served for analysis of factors inducing different responses of cells in a 3D microenvironment under controlled biochemical and biophysical parameters. In the present study, applying the known commercially-viable manufacturing methods to a cyclic olefin copolymer (COC) material resulted in a microfluidic device with enhanced 3D gel capabilities, controlled surface properties, and improved potential to serve high-volume applications. Hot embossing and roller lamination molded and sealed the microfluidic device. A combination of oxygen plasma and thermal treatments enhanced the sealing, ensured proper placement of the 3D gel, and created controlled and stable surface properties within the device. Culture of cells in the new device indicated no adverse effects of the COC material or processing as compared to previous PDMS devices. The results demonstrate a methodology to transition microfludic devices for 3D cell culture from scientific research to high-volume applications with broad clinical impact. PMID:21113663

  9. Direct fabrication of complex 3D hierarchical nanostructures by reactive ion etching of hollow sphere colloidal crystals.

    PubMed

    Zhong, Kuo; Li, Jiaqi; Van Cleuvenbergen, Stijn; Clays, Koen

    2016-09-21

    Direct reactive ion etching (RIE) of hollow SiO2 sphere colloidal crystals (HSCCs) is employed as a facile, low-cost method to fabricate complex three-dimensional (3D) hierarchical nanostructures. These multilayered structures are gradually transformed into nanostructures of increasing complexity by controlling the etching time, without complicated procedures (no mask needed). The resulting 3D topologies are unique, and cannot be obtained through traditional approaches. The formation mechanism of these structures is explained in detail by geometrical modeling during the different etching stages, through shadow effects of the higher layers. SEM images confirm the modeled morphological changes. The nanostructures obtained by our approach show very fine features as small as ∼30 nm. Our approach opens new avenues to directly obtain complex 3D nanostructures from colloidal crystals and can find applications in sensing, templating, and catalysis where fine tuning the specific surface might be critical. PMID:27545098

  10. Design and Fabrication of a Biodegradable, Covalently Crosslinked Shape-Memory Alginate Scaffold for Cell and Growth Factor Delivery

    PubMed Central

    Wang, Lin; Shansky, Janet; Borselli, Cristina; Mooney, David

    2012-01-01

    The successful use of transplanted cells and/or growth factors for tissue repair is limited by a significant cell loss and/or rapid growth factor diffusion soon after implantation. Highly porous alginate scaffolds formed with covalent crosslinking have been used to improve cell survival and growth factor release kinetics, but require open-wound surgical procedures for insertion and have not previously been designed to readily degrade in vivo. In this study, a biodegradable, partially crosslinked alginate scaffold with shape-memory properties was fabricated for minimally invasive surgical applications. A mixture of high and low molecular weight partially oxidized alginate modified with RGD peptides was covalently crosslinked using carbodiimide chemistry. The scaffold was compressible 11-fold and returned to its original shape when rehydrated. Scaffold degradation properties in vitro indicated ∼85% mass loss by 28 days. The greater than 90% porous scaffolds released the recombinant growth factor insulin-like growth factor-1 over several days in vitro and allowed skeletal muscle cell survival, proliferation, and migration from the scaffold over a 28-day period. The compressible scaffold thus has the potential to be delivered by a minimally invasive technique, and when rehydrated in vivo with cells and/or growth factors, could serve as a temporary delivery vehicle for tissue repair. PMID:22646518

  11. Light-driven 3D droplet manipulation on flexible optoelectrowetting devices fabricated by a simple spin-coating method.

    PubMed

    Jiang, Dongyue; Park, Sung-Yong

    2016-05-21

    Technical advances in electrowetting-on-dielectric (EWOD) over the past few years have extended our attraction to three-dimensional (3D) devices capable of providing more flexibility and functionality with larger volumetric capacity than conventional 2D planar ones. However, typical 3D EWOD devices require complex and expensive fabrication processes for patterning and wiring of pixelated electrodes that also restrict the minimum droplet size to be manipulated. Here, we present a flexible single-sided continuous optoelectrowetting (SCOEW) device which is not only fabricated by a spin-coating method without the need for patterning and wiring processes, but also enables light-driven 3D droplet manipulations. To provide photoconductive properties, previous optoelectrowetting (OEW) devices have used amorphous silicon (a-Si) typically fabricated through high-temperature processes over 300 °C such as CVD or PECVD. However, most of the commercially-available flexible substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) experience serious thermal deformation under such high-temperature processes. Because of this compatibility issue of conventional OEW devices with flexible substrates, light-driven 3D droplet manipulations have not yet been demonstrated on flexible substrates. Our study overcomes this compatibility issue by using a polymer-based photoconductive material, titanium oxide phthalocyanine (TiOPc) and thus SCOEW devices can be simply fabricated on flexible substrates through a low-cost, spin-coating method. In this paper, analytical studies were conducted to understand the effects of light patterns on static contact angles and EWOD forces. For experimental validations of our study, flexible SCOEW devices were successfully fabricated through the TiOPc-based spin-coating method and light-driven droplet manipulations (e.g. transportation, merging, and splitting) have been demonstrated on various 3D terrains such as inclined

  12. Fabrication of dielectric and metallo-dielectric 3D nanostructures by direct laser writing and electroless plating

    NASA Astrophysics Data System (ADS)

    Radke, André; Wolff, Frank; Giessen, Harald; Klotzbücher, Thomas

    2010-02-01

    Direct laser writing via two-photon absorption allows the fabrication of three-dimensional dielectric structures with submicron resolution by tightly focusing ultrashort laser pulses into a photo-sensitive material with a high-resolution microscope objective and scanning the laser focus relative to the material. Woodpile photonic crystals fabricated with this method show a characteristic dip in transmission at near-infrared wavelengths. The spectral position of this transmission dip scales with the grating period of the fabricated crystals. Metallo-dielectric structures can be obtained by first fabricating dielectric templates with direct laser writing and subsequently coating the templates with a thin conformal metal film by electroless plating. Contiguous and conducting silver films can be deposited even on convoluted 3D geometries.

  13. Construction and Myogenic Differentiation of 3D Myoblast Tissues Fabricated by Fibronectin-Gelatin Nanofilm Coating

    PubMed Central

    Gribova, Varvara; Liu, Chen Yun; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-01-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ~ 76 µm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  14. Construction and myogenic differentiation of 3D myoblast tissues fabricated by fibronectin-gelatin nanofilm coating.

    PubMed

    Gribova, Varvara; Liu, Chun-Yen; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-06-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ∼76 μm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  15. Electrochemical fabrication of 2D and 3D nickel nanowires using porous anodic alumina templates

    NASA Astrophysics Data System (ADS)

    Mebed, A. M.; Abd-Elnaiem, Alaa M.; Al-Hosiny, Najm M.

    2016-06-01

    Mechanically stable nickel (Ni) nanowires array and nanowires network were synthesized by pulse electrochemical deposition using 2D and 3D porous anodic alumina (PAA) templates. The structures and morphologies of as-prepared films were characterized by X-ray diffraction and scanning electron microscopy, respectively. The grown Ni nanowire using 3D PAA revealed more strength and larger surface area than has grown Ni use 2D PAA template. The prepared nanowires have a face-centered cubic crystal structure with average grain size 15 nm, and the preferred orientation of the nucleation of the nanowires is (111). The diameter of the nanowires is about 50-70 nm with length 3 µm. The resulting 3D Ni nanowire lattice, which provides enhanced mechanical stability and an increased surface area, benefits energy storage and many other applications which utilize the large surface area.

  16. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects.

    PubMed

    Ye, Zhou; Nain, Amrinder S; Behkam, Bahareh

    2016-07-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10(-7) m(2) s(-1)) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b(1.5)∝D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features. PMID:27283144

  17. Fabrication and characterization of direct-written 3D TiO2 woodpile electromagnetic bandgap structures

    NASA Astrophysics Data System (ADS)

    Li, Ji-Jiao; Li, Bo; Peng, Qin-Mei; Zhou, Ji; Li, Long-Tu

    2014-09-01

    Three groups of three-dimensional (3D) TiO2 woodpile electromagnetic gap materials with tailed rheological properties were developed for direct-written fabrication. Appropriate amount of polyethyleneimine (PEI) dispersants allow the preparation of TiO2 inks with a high solid content of 42 vol.%, which enables them to flow through the nozzles easily. The inks exhibit pseudoplastic behavior. The measured microwave characteristics of the results agree well with simulations based on plane wave expansion (PWE).

  18. Improvements in Fabrication of 3D SU-8 Prisms for Low-Coupling-Loss Interconnections Between Fibers and Waveguides

    NASA Astrophysics Data System (ADS)

    Nguyen, Minh-Hang; Chu, Thi-Xuan; Nguyen, Long; Nguyen, Hai-Binh; Lee, Chun-Wei; Tseng, Fan-Gang; Chen, Te-Chang; Lee, Ming-Chang

    2016-07-01

    Fabrication of three-dimensional (3D) SU-8 (an epoxy-based negative photoresist from MicroChem) prisms as low-loss couplers for interconnection between optical components, particularly optical fibers and silicon-on-isolator waveguides (SOI WGs), which have mismatched mode sizes, has been investigated. With an interfacial structure formed by a 3D SU-8 prism partly overlaying an SOI WG end with a portion of buried oxide (BOX) removed under the interface, low-loss coupling is ensured and the transmission efficiency can reach 70%. To fabricate these 3D SU-8 prisms, a simple method with two photolithography steps was used for SU-8 hinges and CYTOP (an amorphous fluoropolymer from AGC Chemicals) prism windows, with mild soft and hard bakes, to define the prism profiles with diluted SU-8 filled in the CYTOP prism windows. A buffered oxide etchant is used to remove BOX parts under the interfaces. Some of the fabricated structures were tested, demonstrating the contribution of overlaying SU-8 prisms to the transmission efficiency of optical interconnections between fibers and SOI WGs.

  19. Fabrication of freeform bone-filling calcium phosphate ceramics by gypsum 3D printing method.

    PubMed

    Lowmunkong, Rungnapa; Sohmura, Taiji; Suzuki, Yumiko; Matsuya, Shigeki; Ishikawa, Kunio

    2009-08-01

    Transformation of gypsum model fabricated by three-dimensional printing (3DP) into hydroxyapatite (HA) by treating in ammonium phosphate solution is possible. However, 3DP powder supplied by the manufacturer contains unknown additives which may be questionable for biomaterials. Accordingly, pure plaster of Paris (POP) powder was used for fabrication in the present study. For accurate fabrication, reduction of supplied binder ink to 80% of standard amount for 3DP powder supplied by the manufacturer was found to be the optimal condition for POP fabrication. Transformation from POP to HA was done by immersing into 1 mol/L ammonium phosphate solution. However, preheating of fabricated POP specimen at 200 degrees C for 30 min to change from calcium sulfate dihydrate into calcium sulfate hemihydrate could accelerate the transformation into HA effectively. To increase compressive strength, HA transformed specimen was sintering at 1150 degrees C for 3 h. The compressive strength increased four times comparing with as transformed HA specimen. However, crystal structure was transformed to beta-TCP due to the chemical reaction between the transformed HA and remained phosphate from ammonium phosphate solution at the sintering temperature. A sophisticated application of the present 3DP method to fabricate the freeform bioceramic for osseous defect was attempted, and jaw bone defect filling biomaterial of beta-TCP and scaffold with macroporous structures could be fabricated. Present 3DP method has possibility to fabricate freeform bioceramic for osseous defect or scaffold. PMID:19145633

  20. Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Megerian, Krikor G.; Von Allmen, Paul A.; Baron, Richard L.

    2010-01-01

    Plasma-enhanced chemical vapor deposition (PECVD) and high-throughput manufacturing techniques for integrating single, aligned carbon nanotubes (CNTs) into novel 3D nanoscale architectures have been developed. First, the PECVD growth technique ensures excellent alignment of the tubes, since the tubes align in the direction of the electric field in the plasma as they are growing. Second, the tubes generated with this technique are all metallic, so their chirality is predetermined, which is important for electronic applications. Third, a wafer-scale manufacturing process was developed that is high-throughput and low-cost, and yet enables the integration of just single, aligned tubes with nanoscale 3D architectures with unprecedented placement accuracy and does not rely on e-beam lithography. Such techniques should lend themselves to the integration of PECVD grown tubes for applications ranging from interconnects, nanoelectromechanical systems (NEMS), sensors, bioprobes, or other 3D electronic devices. Chemically amplified polyhydroxystyrene-resin-based deep UV resists were used in conjunction with excimer laser-based (lambda = 248 nm) step-and-repeat lithography to form Ni catalyst dots = 300 nm in diameter that nucleated single, vertically aligned tubes with high yield using dc PECVD growth. This is the first time such chemically amplified resists have been used, resulting in the nucleation of single, vertically aligned tubes. In addition, novel 3D nanoscale architectures have been created using topdown techniques that integrate single, vertically aligned tubes. These were enabled by implementing techniques that use deep-UV chemically amplified resists for small-feature-size resolution; optical lithography units that allow unprecedented control over layer-to-layer registration; and ICP (inductively coupled plasma) etching techniques that result in near-vertical, high-aspect-ratio, 3D nanoscale architectures, in conjunction with the use of materials that are

  1. Fabrication of 3D Templates Using a Large Depth of Focus Femtosecond Laser

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Fan; Winfield, Richard; O'Brien, Shane; Chen, Liang-Yao

    2009-09-01

    We report the use of a large depth of focus Bessel beam in the fabrication of cell structures. Two axicon lenses are investigated in the formation of high aspect ratio line structures. A sol-gel resin, with good mechanical strength, is polymerised in a modified two-photon polymerisation system. Examples of different two-dimensional grids are presented to show that the lateral resolution can be maintained even in the rapid fabrication of high-sided structures.

  2. Cells (MC3T3-E1)-laden alginate scaffolds fabricated by a modified solid-freeform fabrication process supplemented with an aerosol spraying.

    PubMed

    Ahn, SeungHyun; Lee, HyeongJin; Bonassar, Lawrence J; Kim, GeunHyung

    2012-09-10

    In this study, we propose a new cell encapsulation method consisting of a dispensing method and an aerosol-spraying method. The aerosol spray using a cross-linking agent, calcium chloride (CaCl(2)), was used to control the surface gelation of dispensed alginate struts during dispensing. To show the feasibility of the method, we used preosteoblast (MC3T3-E1) cells. By changing the relationship between the various dispensing/aerosol-spraying conditions and cell viability, we could determine the optimal cell-dispensing process: a nozzle size (240 μm) and an aerosol spray flow rate (0.93 ± 0.12 mL min(-1)), 10 mm s(-1) nozzle moving speed, a 10 wt % concentration of CaCl(2) in the aerosol solution, and 2 wt % concentration of CaCl(2) in the second cross-linking process. Based on these optimized process conditions, we successfully fabricated a three-dimensional, pore-structured, cell-laden alginate scaffold of 20 × 20 × 4.6 mm(3) and 84% cell viability. During long cell culture periods (16, 25, 33, and 45 days), the preosteoblasts in the alginate scaffold survived and proliferated well. PMID:22913233

  3. Microplasma fabrication: from semiconductor technology for 2D-chips and microfluidic channels to rapid prototyping and 3D-printing of microplasma devices

    NASA Astrophysics Data System (ADS)

    Shatford, R.; Karanassios, Vassili

    2014-05-01

    Microplasmas are receiving attention in recent conferences and current scientific literature. In our laboratory, microplasmas-on-chips proved to be particularly attractive. The 2D- and 3D-chips we developed became hybrid because they were fitted with a quartz plate (quartz was used due to its transparency to UV). Fabrication of 2D- and 3D-chips for microplasma research is described. The fabrication methods described ranged from semiconductor fabrication technology, to Computer Numerical Control (CNC) machining, to 3D-printing. These methods may prove to be useful for those contemplating in entering microplasma research but have no access to expensive semiconductor fabrication equipment.

  4. Characterization of the first double-sided 3D radiation sensors fabricated at FBK on 6-inch silicon wafers

    NASA Astrophysics Data System (ADS)

    Sultan, D. M. S.; Mendicino, R.; Boscardin, M.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

    2015-12-01

    Following 3D pixel sensor production for the ATLAS Insertable B-Layer, Fondazione Bruno Kessler (FBK) fabrication facility has recently been upgraded to process 6-inch wafers. In 2014, a test batch was fabricated to check for possible issues relevant to this upgrade. While maintaining a double-sided fabrication technology, some process modifications have been investigated. We report here on the technology and the design of this batch, and present selected results from the electrical characterization of sensors and test structures. Notably, the breakdown voltage is shown to exceed 200 V before irradiation, much higher than in earlier productions, demonstrating robustness in terms of radiation hardness for forthcoming productions aimed at High Luminosity LHC upgrades.

  5. Meshing Preprocessor for the Mesoscopic 3D Finite Element Simulation of 2D and Interlock Fabric Deformation

    NASA Astrophysics Data System (ADS)

    Wendling, A.; Daniel, J. L.; Hivet, G.; Vidal-Sallé, E.; Boisse, P.

    2015-12-01

    Numerical simulation is a powerful tool to predict the mechanical behavior and the feasibility of composite parts. Among the available numerical approaches, as far as woven reinforced composites are concerned, 3D finite element simulation at the mesoscopic scale leads to a good compromise between realism and complexity. At this scale, the fibrous reinforcement is modeled by an interlacement of yarns assumed to be homogeneous that have to be accurately represented. Among the numerous issues induced by these simulations, the first one consists in providing a representative meshed geometrical model of the unit cell at the mesoscopic scale. The second one consists in enabling a fast data input in the finite element software (contacts definition, boundary conditions, elements reorientation, etc.) so as to obtain results within reasonable time. Based on parameterized 3D CAD modeling tool of unit-cells of dry fabrics already developed, this paper presents an efficient strategy which permits an automated meshing of the models with 3D hexahedral elements and to accelerate of several orders of magnitude the simulation data input. Finally, the overall modeling strategy is illustrated by examples of finite element simulation of the mechanical behavior of fabrics.

  6. Fabrication of 3D photocatalytic α-Fe2O3 structure using direct ink writing method

    NASA Astrophysics Data System (ADS)

    Li, Yayun; Li, Bo; Li, Longtu

    2014-02-01

    Three-dimensional (3D) photocatalytic devices are economical and environmental, since they can be easily recycled and reused. In this paper, a kind of 3D photocatalytic device with a rod diameter of 250 μm was fabricated using the aqueous-based α-Fe2O3 ceramic inks by direct ink writing (DIW) method. The properties of the DIW woodpile samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and optical microscope. The result shows that the ink with solid content of 71.4 wt.% exhibits a shear thinning behavior and proper viscoelastic properties, which ensure a feasible extrusion in the whole shaping process. The sample sintered at 800°C in air causes photocatalytic degradation of methylene blue (MB) solution under the ultraviolet (UV) light. The photocatalytic properties of the α-Fe2O3 woodpile structure was characterized by the UV-visible light spectrophotometer, and it was found to be better than that of bulk sample with same weight for its higher specific surface. The DIW technique would offer a potential method for the design and fabrication of 3D photocatalytic devices.

  7. Design, fabrication and characterization of oxidized alginate-gelatin hydrogels for muscle tissue engineering applications.

    PubMed

    Baniasadi, Hossein; Mashayekhan, Shohreh; Fadaoddini, Samira; Haghirsharifzamini, Yasamin

    2016-07-01

    In this study, we reported the preparation of self cross-linked oxidized alginate-gelatin hydrogels for muscle tissue engineering. The effect of oxidation degree (OD) and oxidized alginate/gelatin (OA/GEL) weight ratio were examined and the results showed that in the constant OA/GEL weight ratio, both cross-linking density and Young's modulus enhanced by increasing OD due to increment of aldehyde groups. Furthermore, the degradation rate was increased with increasing OD probably due to decrement in alginate molecular weight during oxidation reaction facilitated degradation of alginate chains. MTT cytotoxicity assays performed on Wharton's Jelly-derived umbilical cord mesenchymal stem cells cultured on hydrogels with OD of 30% showed that the highest rate of cell proliferation belong to hydrogel with OA/GEL weight ratio of 30/70. Overall, it can be concluded from all obtained results that the prepared hydrogel with OA/GEL weight ratio and OD of 30/70 and 30%, respectively, could be proper candidate for use in muscle tissue engineering. PMID:26916948

  8. Fabrication and characterization of novel nano-biocomposite scaffold of chitosan-gelatin-alginate-hydroxyapatite for bone tissue engineering.

    PubMed

    Sharma, Chhavi; Dinda, Amit Kumar; Potdar, Pravin D; Chou, Chia-Fu; Mishra, Narayan Chandra

    2016-07-01

    A novel nano-biocomposite scaffold was fabricated in bead form by applying simple foaming method, using a combination of natural polymers-chitosan, gelatin, alginate and a bioceramic-nano-hydroxyapatite (nHAp). This approach of combining nHAp with natural polymers to fabricate the composite scaffold, can provide good mechanical strength and biological property mimicking natural bone. Environmental scanning electron microscopy (ESEM) images of the nano-biocomposite scaffold revealed the presence of interconnected pores, mostly spread over the whole surface of the scaffold. The nHAp particulates have covered the surface of the composite matrix and made the surface of the scaffold rougher. The scaffold has a porosity of 82% with a mean pore size of 112±19.0μm. Swelling and degradation studies of the scaffold showed that the scaffold possesses excellent properties of hydrophilicity and biodegradability. Short term mechanical testing of the scaffold does not reveal any rupturing after agitation under physiological conditions, which is an indicative of good mechanical stability of the scaffold. In vitro cell culture studies by seeding osteoblast cells over the composite scaffold showed good cell viability, proliferation rate, adhesion and maintenance of osteoblastic phenotype as indicated by MTT assay, ESEM of cell-scaffold construct, histological staining and gene expression studies, respectively. Thus, it could be stated that the nano-biocomposite scaffold of chitosan-gelatin-alginate-nHAp has the paramount importance for applications in bone tissue-engineering in future regenerative therapies. PMID:27127072

  9. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

    NASA Astrophysics Data System (ADS)

    Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

    2016-06-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for

  10. Ship-in-a-bottle integration by hybrid femtosecond laser technology for fabrication of true 3D biochips

    NASA Astrophysics Data System (ADS)

    Sima, Felix; Wu, Dong; Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2015-03-01

    We propose herein the "ship-in-a-bottle" integration of three-dimensional (3D) polymeric sinusoidal ridges inside photosensitive glass microfluidic channel by a hybrid subtractive - additive femtosecond laser processing method. It consists of Femtosecond Laser Assisted Wet Etching (FLAE) of a photosensitive Foturan glass followed by Two-Photon Polymerization (TPP) of a SU-8 negative epoxy-resin. Both subtractive and additive processes are carried out using the same set-up with the change of laser focusing objective only. A 522 nm wavelength of the second harmonic generation from an amplified femtosecond Yb-fiber laser (FCPA µJewel D-400, IMRA America, 1045 nm; pulse width 360 fs, repetition rate 200 kHz) was employed for irradiation. The new method allows lowering the size limit of 3D objects created inside channels to smaller details down to the dimensions of a cell, and improve the structure stability. Sinusoidal periodic patterns and ridges are of great use as base scaffolds for building up new structures on their top or for modulating cell migration, guidance and orientation while created interspaces can be exploited for microfluidic applications. The glass microchannel offers robustness and appropriate dynamic flow conditions for cellular studies while the integrated patterns are reducing the size of structure to the level of cells responsiveness. Taking advantage of the ability to directly fabricate 3D complex shapes, both glass channels and polymeric integrated patterns enable us to 3D spatially design biochips for specific applications.

  11. Dielectrophoresis with 3D microelectrodes fabricated by surface tension assisted lithography.

    PubMed

    Nasabi, Mahyar; Khoshmanesh, Khashayar; Tovar-Lopez, Francisco J; Kalantar-Zadeh, Kourosh; Mitchell, Arnan

    2013-12-01

    This paper demonstrates the utilization of 3D semispherical shaped microelectrodes for dielectrophoretic manipulation of yeast cells. The semispherical microelectrodes are capable of producing strong electric field gradients, and in turn dielectrophoretic forces across a large area of channel cross-section. The semispherical shape of microelectrodes avoids the formation of undesired sharp electric fields along the structure and also minimizes the disturbance of the streamlines of nearby passing fluid. The advantage of semispherical microelectrodes over the planar microelectrodes is demonstrated in a series of numerical simulations and proof-of-concept experiments aimed toward immobilization of viable yeast cells. PMID:24347270

  12. Fabrication and Characterization of a Multichannel 3D Thermopile for Chip Calorimeter Applications

    PubMed Central

    Huynh, Tho Phuoc; Zhang, Yilei; Yehuda, Cohen

    2015-01-01

    Thermal sensors based on thermopiles are some of the most robust and popular temperature sensing technologies across industries and research disciplines. A chip calorimeter with a 3D thermopile layout with a large sensing area and multichannel capacity has been developed, which is highly desired for many applications requiring large reaction chambers or high throughputs, such as biofilm research, drug screening, etc. The performance of the device, including temperature sensitivity and heat power sensitivity, was evaluated. The capability to split the chip calorimeter to multiple channels was also demonstrated, which makes the chip calorimeter very flexible and powerful in many applications. PMID:25654716

  13. 3D MEMS in Standard Processes: Fabrication, Quality Assurance, and Novel Measurement Microstructures

    NASA Technical Reports Server (NTRS)

    Lin, Gisela; Lawton, Russell A.

    2000-01-01

    Three-dimensional MEMS microsystems that are commercially fabricated require minimal post-processing and are easily integrated with CMOS signal processing electronics. Measurements to evaluate the fabrication process (such as cross-sectional imaging and device performance characterization) provide much needed feedback in terms of reliability and quality assurance. MEMS technology is bringing a new class of microscale measurements to fruition. The relatively small size of MEMS microsystems offers the potential for higher fidelity recordings compared to macrosize counterparts, as illustrated in the measurement of muscle cell forces.

  14. Novel and simple route to fabricate 2D ordered gold nanobowl arrays based on 3D colloidal crystals.

    PubMed

    Rao, Yanying; Tao, Qin; An, Ming; Rong, Chunhui; Dong, Jian; Dai, Yurong; Qian, Weiping

    2011-11-01

    In this study, we present a new method to fabricate large-area two-dimensionally (2D) ordered gold nanobowl arrays based on 3D colloidal crystals by wet chemosynthesis, which combines the advantages of a very simple preparation and an applicability to "real" nanomaterials. By combination of in situ growth of gold nanoshell (GNSs) arrays based on three-dimensional (3D) colloidal silica crystals, a monolayer ordered reversed GNS array (2D ordered GNS array) was conveniently manufactured by an acrylic ester modified biaxial oriented polypropylene (BOPP). 2D ordered gold nanobowl array with adjustable periodic holes, good stability, reproducibility, and repeatability could be obtained when the silica core was etched by HF solution. The surface-enhanced Raman scattering (SERS) enhancement factor (EF) of this 2D ordered gold nanobowl array could reach 1.27 × 10(7), which shows high SERS enhancing activity and can be used as a universal SERS substrate. PMID:21932785

  15. Fabrication of chitosan-silver nanoparticle hybrid 3D porous structure as a SERS substrate for biomedical applications

    NASA Astrophysics Data System (ADS)

    Jung, Gyeong-Bok; Kim, Ji-Hye; Burm, Jin Sik; Park, Hun-Kuk

    2013-05-01

    We propose a simple, low-cost, large-area, and functional surface enhanced Raman scattering (SERS) substrate for biomedical applications. The SERS substrate with chitosan-silver nanoparticles (chitosan-Ag NPs) hybrid 3D porous structure was fabricated simply by a one-step method. The chitosan was used as a template for the Ag NPs deposition. SERS enhancement by the chitosan-Ag NPs substrate was experimentally verified using rhodamine B as an analyte. Thiolated single stranded DNA was also measured for atopic dermatitis genetic markers (chemokines CCL17) at a low concentration of 5 pM. We successfully designed a novel SERS substrate with silver nanoparticle hybridized 3D porous chitosan that has the potential to become a highly sensitive and selective tool for biomedical applications.

  16. 3D nanoimprint for NIR Fabry-Pérot filter arrays: fabrication, characterization and comparison of different cavity designs

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc Toan; Ababtain, Muath; Memon, Imran; Ullah, Anayat; Istock, André; Woidt, Carsten; Xie, Weichang; Lehmann, Peter; Hillmer, Hartmut

    2016-02-01

    We report on the fabrication of miniaturized NIR spectrometers based on arrays of multiple Fabry-Pérot (FP) filters. The various cavities of different height are fabricated via a single patterning step using high resolution 3D nanoimprint technology. Today, low-cost patterning of extended cavity heights for NIR filters using the conventional spin-coated nanoimprint methodology is not available because of insufficient coating layers and low mobility of the resist materials to fill extended cavity structures. Our investigation focuses on reducing the technological effort for fabrication of homogeneous extended cavities. We study alternative cavity designs, including a new resist and apply large-area 3D nanoimprint based on hybrid mold and UV Substrate Conformal Imprint Lithography (UV-SCIL) to overcome these limitations. We compare three different solutions, i.e. (1) applying multiple spin coating of the resist to obtain thicker initial resist layers, (2) introducing a hybrid cavity (combination of a thin oxide layer and the organic cavity) to compensate the height differences, and (3) optimizing the imprint process with a novel resist material. The imprint results based on these methods demonstrate the implementation of NIR FP filters with high transmission intensity (best single filter transmission >90 %) and small line widths (<5 nm in full width at half maximum).

  17. Design and fabrication of cast orthopedic implants with freeform surface textures from 3-D printed ceramic shell.

    PubMed

    Curodeau, A; Sachs, E; Caldarise, S

    2000-09-01

    Three-dimensional printing is a solid freeform fabrication process, which creates parts directly from a computer model. The parts are built by repetitively spreading a layer of powder and selectively joining the powder in the layer by ink-jet printing of a binder material. 3D printing was applied to the fabrication of sub-millimeter surface textures with overhang and undercut geometries for use in orthopedic prostheses as bony ingrowth structures. 3D printing is used to fabricate ceramic molds of alumina powder and silica binder, and these molds are used to cast the bony ingrowth surfaces of Co-Cr (ASTM F75) alloy. Minimum positive feature sizes of the ceramic mold and, therefore, minimum negative feature sizes of castings were determined to be approximately 200 x 200 x 175 microm and were limited by the strength of ceramic needed to withstand handling. Minimum negative feature sizes in the ceramic mold and, therefore, minimum positive features in the casting were found to be approximately 350 x 350 x 175 microm and were determined by limitations on removal of powder from the ceramic and the pressure required to fill these small features with molten metal during casting. Textures were designed with 5 layers of distinct geometric definition, allowing for the design of overhung geometry with overall porosity ranging from 30-70%. Features as small as 350 x 350 x 200 microm were included in these designs and successfully cast. PMID:10984701

  18. Fabrication of a 3D active mixer based on deformable Fe-doped PDMS cones with magnetic actuation

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza; Alizadeh, Elaheh

    2012-11-01

    In this paper an active 3D mixer for lab-on-chip applications is presented. The micrometer size cone shape holes are ablated on a PMMA sheet utilizing a CO2 laser. The holes are filled with Fe micro-particles and the whole structure is molded with PDMS which cause the Fe micro-particles to be trapped in a PDMS cone structure. These Fe-doped PDMS cones are placed in a PMMA micro-channel structure fabricated by CO2 laser machining. By applying an external periodic magnetic field, the cones periodically bend in the micro-channel and stir the fluid. The fabrication method and the effect of the magnetic field on the bending of the cones with different aspect ratios is also discussed utilizing computer simulation. Doping the polymers with micro- and nano-metallic particles has been carried out by different research groups before, but according to our knowledge, application of such structures for the fabrication of a 3D active mixer has not been presented before.

  19. 3D Imaging with a Single-Aperture 3-mm Objective Lens: Concept, Fabrication and Test

    NASA Technical Reports Server (NTRS)

    Korniski, Ron; Bae, Sam Y.; Shearn, Mike; Manohara, Harish; Shahinian, Hrayr

    2011-01-01

    There are many advantages to minimally invasive surgery (MIS). An endoscope is the optical system of choice by the surgeon for MIS. The smaller the incision or opening made to perform the surgery, the smaller the optical system needed. For minimally invasive neurological and skull base surgeries the openings are typically 10-mm in diameter (dime sized) or less. The largest outside diameter (OD) endoscope used is 4mm. A significant drawback to endoscopic MIS is that it only provides a monocular view of the surgical site thereby lacking depth information for the surgeon. A stereo view would provide the surgeon instantaneous depth information of the surroundings within the field of view, a significant advantage especially during brain surgery. Providing 3D imaging in an endoscopic objective lens system presents significant challenges because of the tight packaging constraints. This paper presents a promising new technique for endoscopic 3D imaging that uses a single lens system with complementary multi-bandpass filters (CMBFs), and describes the proof-of-concept demonstrations performed to date validating the technique. These demonstrations of the technique have utilized many commercial off-the-shelf (COTS) components including the ones used in the endoscope objective.

  20. Design and fabrication of 3D-printed anatomically shaped lumbar cage for intervertebral disc (IVD) degeneration treatment.

    PubMed

    Serra, T; Capelli, C; Toumpaniari, R; Orriss, I R; Leong, J J H; Dalgarno, K; Kalaskar, D M

    2016-01-01

    Spinal fusion is the gold standard surgical procedure for degenerative spinal conditions when conservative therapies have been unsuccessful in rehabilitation of patients. Novel strategies are required to improve biocompatibility and osseointegration of traditionally used materials for lumbar cages. Furthermore, new design and technologies are needed to bridge the gap due to the shortage of optimal implant sizes to fill the intervertebral disc defect. Within this context, additive manufacturing technology presents an excellent opportunity to fabricate ergonomic shape medical implants. The goal of this study is to design and manufacture a 3D-printed lumbar cage for lumbar interbody fusion. Optimisations of the proposed implant design and its printing parameters were achieved via in silico analysis. The final construct was characterised via scanning electron microscopy, contact angle, x-ray micro computed tomography (μCT), atomic force microscopy, and compressive test. Preliminary in vitro cell culture tests such as morphological assessment and metabolic activities were performed to access biocompatibility of 3D-printed constructs. Results of in silico analysis provided a useful platform to test preliminary cage design and to find an optimal value of filling density for 3D printing process. Surface characterisation confirmed a uniform coating of nHAp with nanoscale topography. Mechanical evaluation showed mechanical properties of final cage design similar to that of trabecular bone. Preliminary cell culture results showed promising results in terms of cell growth and activity confirming biocompatibility of constructs. Thus for the first time, design optimisation based on computational and experimental analysis combined with the 3D-printing technique for intervertebral fusion cage has been reported in a single study. 3D-printing is a promising technique for medical applications and this study paves the way for future development of customised implants in spinal

  1. Fabrication of 3-D Photonic Band Gap Crystals Via Colloidal Self-Assembly

    NASA Technical Reports Server (NTRS)

    Subramaniam, Girija; Blank, Shannon

    2005-01-01

    The behavior of photons in a Photonic Crystals, PCs, is like that of electrons in a semiconductor in that, it prohibits light propagation over a band of frequencies, called Photonic Band Gap, PBG. Photons cannot exist in these band gaps like the forbidden bands of electrons. Thus, PCs lend themselves as potential candidates for devices based on the gap phenomenon. The popular research on PCs stem from their ability to confine light with minimal losses. Large scale 3-D PCs with a PBG in the visible or near infra red region will make optical transistors and sharp bent optical fibers. Efforts are directed to use PCs for information processing and it is not long before we can have optical integrated circuits in the place of electronic ones.

  2. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    NASA Astrophysics Data System (ADS)

    Ionita, Ciprian N.; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R.; Xiang, Jianping; Snyder, Kenneth V.; Siddiqui, Adnan H.; Levy, Elad I.; Meng, Hui; Rudin, Stephen

    2014-03-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a "marching cubes" algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing.

  3. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    PubMed Central

    Ionita, Ciprian N; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R; Xiang, Jianping; Snyder, Kenneth V; Siddiqui, Adnan H; Levy, Elad I; Meng, Hui; Rudin, Stephen

    2014-01-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a “marching cubes” algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing. PMID:25300886

  4. Inverted Yablonovite-like 3D photonic crystals fabricated by laser nanolithography

    NASA Astrophysics Data System (ADS)

    Shishkin, Ivan I.; Samusev, Kirill B.; Rybin, Mikhail V.; Limonov, Mikhail F.; Kivshar, Yuri S.; Gaidukeviciute, Arune; Kiyan, Roman V.; Chichkov, Boris N.

    2012-06-01

    We report on the fabrication of inverted Yablonovite-like three-dimensional photonic crystals by nonlinear optical nanolithography based on two-photon polymerization of a zirconium propoxide hybrid organic-inorganic material with Irgacure 369 as photo-initiator. Advantage of this material is ultra-low shrinkage that guaranty high fabrication fidelity. Images of the fabricated structure are obtained with a scanning electron microscope. The photonic crystal consists of three sets of nearly cylindrical structural elements directed along the three lattice vectors of the fcc lattice and cross each other at certain angles to produce inverted Yablonovite geometry. To investigate photonic properties of the inverted Yablonovite structures, we calculate the photonic band structure for ten lowest-frequency electromagnetic modes. In contrast to the direct Yablonovite structure that has a complete photonic band gap between the second and third bands, we find no complete photonic band gaps in the inverted Yablonovite lattice. This situation is opposite to the case of fcc lattice of close-packed dielectric spheres in air that has a complete photonic band gap only for the inverted geometry.

  5. Engineered cardiac micromodules for the in vitro fabrication of 3D endogenous macro-tissues.

    PubMed

    Totaro, A; Urciuolo, F; Imparato, G; Netti, P A

    2016-01-01

    The in vitro fabrication of an endogenous cardiac muscle would have a high impact for both in vitro studies concerning cardiac tissue physiology and pathology, as well as in vivo application to potentially repair infarcted myocardium. To reach this aim, we engineered a new class of cardiac tissue precursor (CTP), specifically conceived in order to promote the synthesis and the assembly of a cardiac extracellular matrix (ECM). The CTPs were obtained by culturing a mixed cardiac cell population, composed of myocyte and non-myocyte cells, into porous gelatin microspheres in a dynamic bioreactor. By engineering the culture conditions, the CTP developed both beating properties and an endogenous immature cardiac ECM. By following a bottom-up approach, a macrotissue was fabricated by molding and packing the engineered tissue precursor in a maturation chamber. During the macrotissue formation, the tissue precursors acted as cardiac tissue depots by promoting the formation of an endogenous and interconnected cardiac network embedding the cells and the microbeads. The myocytes cell fraction pulled on ECM network and induced its compaction against the internal posts represented by the initial porous microbeads. This reciprocal interplay induced ECM consolidation without the use of external biophysical stimuli by leading to the formation of a beating and endogenous macrotissue. We have thus engineered a new class of cardiac micromodules and show its potential for the fabrication of endogenous cardiac tissue models useful for in vitro studies that involve the cardiac tissue remodeling. PMID:27213995

  6. 3D printing in X-ray and Gamma-Ray Imaging: A novel method for fabricating high-density imaging apertures☆

    PubMed Central

    Miller, Brian W.; Moore, Jared W.; Barrett, Harrison H.; Fryé, Teresa; Adler, Steven; Sery, Joe; Furenlid, Lars R.

    2011-01-01

    Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for cost-effective fabrication of custom components in gamma-ray and X-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum are presented. PMID:22199414

  7. Photolithographic fabrication of 3D Penrose-like quasi-photonic crystal polymeric templates utilizing lab-made phasemask

    NASA Astrophysics Data System (ADS)

    Torres-Lazos, Faraon

    Photonic crystals (PhC) have recently become of great interest because of their potential as replacement of electronics and/or supplement to semiconductors technology. The PhC's capability to make compact integrated optical circuits has already made possible the laboratory manufacture of an array of different types of optical waveguides, cavities and filters. The work presented here aimed to simultaneously fabricate a 3D-PhC templates employing six-beam holographic lithography. The basic procedures included recording gratings using interference field of laser sources in a photoresist coating on a glass substrate. The manufacturing method utilized only one optical element, a phasemask, drastically reducing the complexity of fabrication by eliminating the need multiple mirrors and beam splitters. Using this approach, a template can be created with a single exposure to laser source and just varying exposure times, increasing reproducibility.

  8. Fabrication of 3D copper oxide structure by holographic lithography for photoelectrochemical electrodes.

    PubMed

    Jin, Woo-Min; Kang, Ji-Hwan; Moon, Jun Hyuk

    2010-11-01

    We fabricated three-dimensional copper oxide structure by holographic lithography and electroless deposition. A five-beam interference pattern defined a woodpile structure of SU-8. The surface modification of SU-8 structure was achieved by multilayer coating of polyelectrolyte, which is critical for activating the surface for the reduction of copper. Copper was deposited onto the surface of the structure by electroless deposition, and subsequent calcinations removed the SU-8 structure and simultaneously oxidized the copper into copper oxide. The porous copper oxide structure was used as a photoelectrochemical electrode. Because of the highly porous structure, our structure showed higher photocurrent efficiency. PMID:21062017

  9. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

  10. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition.

    PubMed

    Zhan, Hualin; Garrett, David J; Apollo, Nicholas V; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm(3), were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail. PMID:26805546

  11. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    PubMed Central

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail. PMID:26805546

  12. Design and fabrication of concave-convex lens for head mounted virtual reality 3D glasses

    NASA Astrophysics Data System (ADS)

    Deng, Zhaoyang; Cheng, Dewen; Hu, Yuan; Huang, Yifan; Wang, Yongtian

    2015-08-01

    As a kind of light-weighted and convenient tool to achieve stereoscopic vision, virtual reality glasses are gaining more popularity nowadays. For these glasses, molded plastic lenses are often adopted to handle both the imaging property and the cost of massive production. However, the as-built performance of the glass depends on both the optical design and the injection molding process, and maintaining the profile of the lens during injection molding process presents particular challenges. In this paper, optical design is combined with processing simulation analysis to obtain a design result suitable for injection molding. Based on the design and analysis results, different experiments are done using high-quality equipment to optimize the process parameters of injection molding. Finally, a single concave-convex lens is designed with a field-of-view of 90° for the virtual reality 3D glasses. The as-built profile error of the glass lens is controlled within 5μm, which indicates that the designed shape of the lens is fairly realized and the designed optical performance can thus be achieved.

  13. Fabrication of fully undercut ZnO-based photonic crystal membranes with 3D optical confinement

    NASA Astrophysics Data System (ADS)

    Hoffmann, Sandro Phil; Albert, Maximilian; Meier, Cedrik

    2016-09-01

    For studying nonlinear photonics, a highly controllable emission of photons with specific properties is essential. Two-dimensional photonic crystals (PhCs) have proven to be an excellent candidate for manipulating photon emission due to resonator-based effects. Additionally, zinc oxide (ZnO) has high susceptibility coefficients and therefore shows pronounced nonlinear effects. However, in order to fabricate such a cavity, a fully undercut ZnO membrane is required, which is a challenging problem due to poor selectivity of the known etching chemistry for typical substrates such as sapphire or ZnO. The aim of this paper is to demonstrate and characterize fully undercut photonic crystal membranes based on a thin ZnO film sandwiched between two layers of silicon dioxide (SiO2) on silicon substrates, from the initial growth of the heterostructure throughout the entire fabrication process. This process leads to a fully undercut ZnO-based membrane with adjustable optical confinement in all three dimensions. Finally, photonic resonances within the tailored photonic band gap are achieved due to optimized PhC-design (in-plane) and total internal reflection in the z-direction. The presented approach enables a variety of photon based resonator structures in the UV regime for studying nonlinear effects, including photon-exciton coupling and all-optical switching.

  14. Fabrication of a three dimensional particle focusing microfluidic device using a 3D printer, PDMS, and glass

    NASA Astrophysics Data System (ADS)

    Collette, Robyn; Rosen, Daniel; Shirk, Kathryn

    Microfluidic devices have high importance in fields such as bioanalysis because they can manipulate volumes of fluid in the range of microliters to picoliters. Small samples can be quickly and easily tested using complex microfluidic devices. Typically, these devices are created through lithography techniques, which can be costly and time consuming. It has been shown that inexpensive microfluidic devices can be produced quickly using a 3D printer and PDMS. However, a size limitation prohibits the fabrication of precisely controlled microchannels. By using shrinking materials in combination with 3D printing of flow-focusing geometries, this limitation can be overcome. This research seeks to employ these techniques to quickly fabricate an inexpensive, working device with three dimensional particle focusing capabilities. By modifying the channel geometry, colloidal particles in a solution will be focused into a single beam when passed through this device. The ability to focus particles is necessary for a variety of biological applications which requires precise detection and characterization of particles in a sample. We would like to thank the Shippensburg University Undergraduate Research Grant Program for their generous funding.

  15. Novel crosslinked alginate/hyaluronic acid hydrogels for nerve tissue engineering

    NASA Astrophysics Data System (ADS)

    Wang, Min-Dan; Zhai, Peng; Schreyer, David J.; Zheng, Ruo-Shi; Sun, Xiao-Dan; Cui, Fu-Zhai; Chen, Xiong-Biao

    2013-09-01

    Artificial tissue engineering scaffolds can potentially provide support and guidance for the regrowth of severed axons following nerve injury. In this study, a hybrid biomaterial composed of alginate and hyaluronic acid (HA) was synthesized and characterized in terms of its suitability for covalent modification, biocompatibility for living Schwann cells and feasibility to construct three dimensional (3D) scaffolds. Carbodiimide mediated amide formation for the purpose of covalent crosslinking of the HA was carried out in the presence of calciumions that ionically crosslink alginate. Amide formation was found to be dependent on the concentrations of carbodiimide and calcium chloride. The double-crosslinked composite hydrogels display biocompatibility that is comparable to simple HA hydrogels, allowing for Schwann cell survival and growth. No significant difference was found between composite hydrogels made from different ratios of alginate and HA. A 3D BioPlotter™ rapid prototyping system was used to fabricate 3D scaffolds. The result indicated that combining HA with alginate facilitated the fabrication process and that 3D scaffolds with porous inner structure can be fabricated from the composite hydrogels, but not from HA alone. This information provides a basis for continuing in vitro and in vivo tests of the suitability of alginate/HA hydrogel as a biomaterial to create living cell scaffolds to support nerve regeneration.

  16. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

    PubMed

    Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

    2016-07-01

    Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016. PMID:26999521

  17. Granular gel support-enabled extrusion of three-dimensional alginate and cellular structures.

    PubMed

    Jin, Yifei; Compaan, Ashley; Bhattacharjee, Tapomoy; Huang, Yong

    2016-06-01

    Freeform fabrication of soft structures has been of great interest in recent years. In particular, it is viewed as a critical step toward the grand vision of organ printing--the on-demand design and fabrication of three-dimensional (3D) human organ constructs for implantation and regenerative medicine. The objective of this study is to develop a novel granular gel support material-enabled, two-step gelation-based 'printing-then-gelation' approach to fabricate 3D alginate structures using filament extrusion. Specifically, a granular Carbopol microgel bath holds the ungelled alginate structure being extruded, avoiding the instantaneous gelation of each printed layer as well as resultant surface tension-induced nozzle clogging. Since Carbopol microgels react with multivalent cations, which are needed for alginate crosslinking, gelatin is introduced as a sacrificial material to make an alginate and gelatin bioink for extrusion, which gels thermally (step-one gelation) to initially stabilize the printed structure for removal from Carbopol. Then gelatin is melted and diffused away while alginate is ionically crosslinked in a 37 °C calcium chloride bath (step-two gelation), resulting in an alginate structure. The proposed 'printing-then-gelation' approach works for alginate structure fabrication, and it is also applicable for the printing of cellular constructs and other similar homogeneous soft structures using a two-step or even multi-step approach. The main conclusions are: (1) 0.8% (w/v) Carbopol bath with a neutral pH value may be most suitable for soft structure printing; (2) it is most effective to use a 0.9% (w/v) NaCl solution to facilitate the removal of residual Carbopol; and (3) alginate structures fabricated using the proposed approach demonstrate better mechanical properties than those fabricated using the conventional 'gelation-while-printing' approach. PMID:27257095

  18. An extremely simple method for fabricating 3D protein microarrays with an anti-fouling background and high protein capacity.

    PubMed

    Lin, Zhifeng; Ma, Yuhong; Zhao, Changwen; Chen, Ruichao; Zhu, Xing; Zhang, Lihua; Yan, Xu; Yang, Wantai

    2014-07-21

    Protein microarrays have become vital tools for various applications in biomedicine and bio-analysis during the past decade. The intense requirements for a lower detection limit and industrialization in this area have resulted in a persistent pursuit to fabricate protein microarrays with a low background and high signal intensity via simple methods. Here, we report on an extremely simple strategy to create three-dimensional (3D) protein microarrays with an anti-fouling background and a high protein capacity by photo-induced surface sequential controlled/living graft polymerization developed in our lab. According to this strategy, "dormant" groups of isopropyl thioxanthone semipinacol (ITXSP) were first introduced to a polymeric substrate through ultraviolet (UV)-induced surface abstraction of hydrogen, followed by a coupling reaction. Under visible light irradiation, the ITXSP groups were photolyzed to initiate surface living graft polymerization of poly(ethylene glycol) methyl methacrylate (PEGMMA), thus introducing PEG brushes to the substrate to generate a full anti-fouling background. Due to the living nature of this graft polymerization, there were still ITXSP groups on the chain ends of the PEG brushes. Therefore, by in situ secondary living graft cross-linking copolymerization of glycidyl methacrylate (GMA) and polyethylene glycol diacrylate (PEGDA), we could finally plant height-controllable cylinder microarrays of a 3D PEG network containing reactive epoxy groups onto the PEG brushes. Through a commonly used reaction of amine and epoxy groups, the proteins could readily be covalently immobilized onto the microarrays. This delicate design aims to overcome two universal limitations in protein microarrays: a full anti-fouling background can effectively eliminate noise caused by non-specific absorption and a 3D reactive network provides a larger protein-loading capacity to improve signal intensity. The results of non-specific protein absorption tests

  19. A simple strategy to fabricate poly (acrylamide-co-alginate)/gold nanocomposites for inactivation of bacteria

    NASA Astrophysics Data System (ADS)

    Zhang, Yanan; Lou, Zhichao; Zhang, Xiaohong; Hu, Xiaodan; Zhang, Haiqian

    2014-12-01

    A facile and efficient approach to prepare uniform gold nanoparticles (Au NPs) in hybrid hydrogel consisting of acrylamide (AM) and alginate (SA) for antibacterial applications is reported. In this study, reduction of gold ions by acrylamide and alginate (AM-SA) occurred before the polymerization and as-obtained gold colloids are stabilized by AM-SA immediately in the absence of commonly used reducing agents and protective reagents. Via transmittance electron microscopy results, we can conclude that the obtained gold nanoparticles in hydrogel are well dispersed. Furthermore, ultraviolet-visible absorption spectroscopy, Fourier transform infrared and thermogravimetric analysis were used to characterize the structure and composition of the synthetic nanocomposites. Our approach provides well-dispersed nanoparticles around 8 mm in size. It is important to underline that nanoparticle aggregation was not observed during and after gel formation. The prepared Au NPs exhibited remarkable stability in the presence of high pH s, and a range of salt concentrations. Importantly, the hydrogel/gold nanocomposites showed a non-compromised activity to inhibit the growth of a model bacterium, Escherichia coli. With their excellent mechanical behavior, as well as the remained antibacterial activity, the nanocomposites should get various potential applications in the fields of pharmaceutical science and tissue engineering.

  20. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-06-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  1. 3D microfluidic chips with integrated functional microelements fabricated by a femtosecond laser for studying the gliding mechanism of cyanobacteria.

    PubMed

    Hanada, Yasutaka; Sugioka, Koji; Shihira-Ishikawa, Ikuko; Kawano, Hiroyuki; Miyawaki, Atsushi; Midorikawa, Katsumi

    2011-06-21

    Phormidium, a genus of filamentous cyanobacteria, forms endosymbiotic associations with seedling roots that accelerate the growth of the vegetable seedlings. Understanding the gliding mechanism of Phormidium will facilitate improved formation of this association and increased vegetable production. To observe the gliding movements, we fabricated various microfluidic chips termed nanoaquariums using a femtosecond (fs) laser. Direct fs laser writing, followed by annealing and successive wet etching in dilute hydrofluoric acid solution, can easily produce three-dimensional (3D) microfluidics with different structures embedded in a photostructurable glass. Using the fs laser, optical waveguides and filters were integrated with the microfluidic structures in the microchips, allowing the gliding mechanism to be more easily clarified. Using this apparatus, we found that CO(2) secreted from the seedling root attracts Phormidium in the presence of light, and determined the light intensity and specific wavelength necessary for gliding. PMID:21562650

  2. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-04-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  3. SU-C-213-02: Characterizing 3D Printing in the Fabrication of Variable Density Phantoms

    SciTech Connect

    Madamesila, J; McGeachy, P; Villarreal-Barajas, J; Khan, R

    2015-06-15

    Purpose: In this work, we present characterization, process flow, quality control and application of 3D fabricated low density phantoms for radiotherapy quality assurance. Methods: A Rostock delta 3D printer using polystyrene filament of diameter 1.75 mm was used to print geometric volumes of 2×2×1 cm{sup 3} of varying densities. The variable densities of 0.1 to 0.75 g/cm {sup 3} were created by modulating the infill. A computed tomography (CT) scan was performed to establish an infill-density calibration curve as well as characterize the quality of the print such as uniformity and the infill pattern. The time required to print these volumes was also recorded. Using the calibration, two low density cones (0.19, 0.52 g/cm{sup 3}) were printed and benchmarked against commercially available phantoms. The dosimetric validation of the low density scaling of Anisotropic Analytical Algorithm (AAA) was performed by using a 0.5 g/cm{sup 3} slab of 10×10×2.4 cm{sup 3} with EBT3 GafChromic film. The gamma analysis at 3%/3mm criteria were compared for the measured and computed dose planes. Results: Analysis of the volume of air pockets in the infill resulted in a reasonable uniformity for densities 0.4 to 0.75 g/cm{sup 3}. Printed phantoms with densities below 0.4 g/cm{sup 3} exhibited a higher ratio of air to polystyrene resulting in large non-uniformity. Compared to the commercial inserts, good agreement was observed only for the printed 0.52 g/cm{sup 3} cone. Dosimetric comparison for a printed low density volume placed in-between layers of solid water resulted in >95% gamma agreement between AAA calculated dose planes and measured EBT3 films for a 6MV 5×5 cm{sup 2} clinical beam. The comparison showed disagreement in the penumbra region. Conclusion: In conclusion, 3D printing technology opens the door to desktop fabrication of variable density phantoms at economical prices in an efficient manner for the quality assurance needs of a small clinic.

  4. Cell-Laden Poly(ɛ-caprolactone)/Alginate Hybrid Scaffolds Fabricated by an Aerosol Cross-Linking Process for Obtaining Homogeneous Cell Distribution: Fabrication, Seeding Efficiency, and Cell Proliferation and Distribution

    PubMed Central

    Lee, HyeongJin; Ahn, SeungHyun; Bonassar, Lawrence J.; Chun, Wook

    2013-01-01

    Generally, solid-freeform fabricated scaffolds show a controllable pore structure (pore size, porosity, pore connectivity, and permeability) and mechanical properties by using computer-aided techniques. Although the scaffolds can provide repeated and appropriate pore structures for tissue regeneration, they have a low biological activity, such as low cell-seeding efficiency and nonuniform cell density in the scaffold interior after a long culture period, due to a large pore size and completely open pores. Here we fabricated three different poly(ɛ-caprolactone) (PCL)/alginate scaffolds: (1) a rapid prototyped porous PCL scaffold coated with an alginate, (2) the same PCL scaffold coated with a mixture of alginate and cells, and (3) a multidispensed hybrid PCL/alginate scaffold embedded with cell-laden alginate struts. The three scaffolds had similar micropore structures (pore size=430–580 μm, porosity=62%–68%, square pore shape). Preosteoblast cells (MC3T3-E1) were used at the same cell density in each scaffold. By measuring cell-seeding efficiency, cell viability, and cell distribution after various periods of culturing, we sought to determine which scaffold was more appropriate for homogeneously regenerated tissues. PMID:23469894

  5. Fabrication of a novel dual mode cholesterol biosensor using titanium dioxide nanowire bridged 3D graphene nanostacks.

    PubMed

    Komathi, S; Muthuchamy, N; Lee, K-P; Gopalan, A-I

    2016-10-15

    Herein, we fabricated a novel electrochemical-photoelectrochemical (PEC) dual-mode cholesterol biosensor based on graphene (G) sheets interconnected-graphene embedded titanium nanowires (TiO2(G)-NWs) 3D nanostacks (designated as G/Ti(G) 3DNS) by exploiting the beneficial characteristics of G and TiO2-NWs to achieve good selectivity and high sensitivity for cholesterol detection. The G/Ti(G) 3DNS was fabricated by the reaction between functionalized G and TiO2(G)-NWs. Cholesterol oxidase (ChOx) was subsequently immobilized in to G/Ti(G) 3DNS using chitosan (CS) as the binder and the dual mode G/Ti(G) 3DNS/CS/ChOx biosensor was fabricated. The electro-optical properties of the G/Ti(G) 3DNS/CS/ChOx bioelectrode were characterized by cyclic voltammetry and UV-vis diffuse reflection spectroscopy. The cyclic voltammetry of immobilized ChOx showed a pair of well-defined redox peaks indicating direct electron transfer (DET) of ChOx. The amperometric reduction peak current (at -0.05V) linearly increased with increase in cholesterol concentration. The G/Ti(G) 3DNS/CS/ChOx bioelectrode was selective to cholesterol with a remarkable sensitivity (3.82μA/cm(2)mM) and a lower detection limit (6μM). Also, G/Ti(G) 3DNS/CS/ChOx functioned as photoelectrode and exhibited selective detection of cholesterol under a low bias voltage and light irradiation. Kinetic parameters, reproducibility, repeatability, storage stability and effect of temperature and pH were evaluated. We envisage that G/Ti(G) 3DNS with its prospective characteristics, would be a promising material for wide range of biosensing applications. PMID:26611566

  6. Facile Bench-Top Fabrication of Enclosed Circular Microchannels Provides 3D Confined Structure for Growth of Prostate Epithelial Cells

    PubMed Central

    Dolega, Monika E.; Wagh, Jayesh; Gerbaud, Sophie; Kermarrec, Frederique; Alcaraz, Jean-Pierre; Martin, Donald K.; Gidrol, Xavier; Picollet-D’hahan, Nathalie

    2014-01-01

    We present a simple bench-top method to fabricate enclosed circular channels for biological experiments. Fabricating the channels takes less than 2 hours by using glass capillaries of various diameters (from 100 µm up to 400 µm) as a mould in PDMS. The inner surface of microchannels prepared in this way was coated with a thin membrane of either Matrigel or a layer-by-layer polyelectrolyte to control cellular adhesion. The microchannels were then used as scaffolds for 3D-confined epithelial cell culture. To show that our device can be used with several epithelial cell types from exocrine glandular tissues, we performed our biological studies on adherent epithelial prostate cells (non-malignant RWPE-1 and invasive PC3) and also on breast (non-malignant MCF10A) cells We observed that in static conditions cells adhere and proliferate to form a confluent layer in channels of 150 µm in diameter and larger, whereas cellular viability decreases with decreasing diameter of the channel. Matrigel and PSS (poly (sodium 4-styrenesulphonate)) promote cell adhesion, whereas the cell proliferation rate was reduced on the PAH (poly (allylamine hydrochloride))-terminated surface. Moreover infusing channels with a continuous flow did not induce any cellular detachment. Our system is designed to simply grow cells in a microchannel structure and could be easily fabricated in any biological laboratory. It offers opportunities to grow epithelial cells that support the formation of a light. This system could be eventually used, for example, to collect cellular secretions, or study cell responses to graduated hypoxia conditions, to chemicals (drugs, siRNA, …) and/or physiological shear stress. PMID:24945245

  7. Microstructure and Properties of DCP-Derived W-ZrC Composite Using Nontoxic Sodium Alginate to Fabricate WC Preform

    NASA Astrophysics Data System (ADS)

    Najafzadeh Khoee, Ali Asghar; Habibolahzadeh, Ali; Qods, Fathallah; Baharvandi, Hamidreza

    2015-04-01

    In the present work, tungsten carbide (WC) preforms were fabricated by gel-casting process, using different nontoxic Na-alginate to tertiary calcium phosphate ratios and different loadings of WC powder in the initial slurries. The gel-cast green bodies were dried and pre-sintered at 1723 K for 4 h and then reactively infiltrated by molten Zr2Cu at 1623 K for 0.5 h, to produce W-ZrC composite via displacive compensation of porosity process. The phases, microstructures, and mechanical properties of the preforms and the W-ZrC composites were investigated by Fourier transform infrared spectroscope, x-ray diffractometer (XRD), scanning electron microscope (SEM), image analyzer, and universal mechanical testing machine. XRD results, SEM micrographs, and elemental maps indicated uniform distribution of phases (W and ZrC) and elements (W, Zr, and C). Flexural strengths and hardness of the fabricated composites were in the ranges of 429-460 MPa and 7.5-9.5 GPa, respectively. Fractography studies revealed two types of dimple rupture and cleavage fracture modes in different composite samples. The W-ZrC composite was ablated by an oxyacetylene flame for 60 s. The mean value of mass and linear ablation rates of the composite were 2.1 ± 0.1 mg/s and 3.6 ± 0.5 µm/s, respectively.

  8. An additive manufacturing-based PCL-alginate-chondrocyte bioprinted scaffold for cartilage tissue engineering.

    PubMed

    Kundu, Joydip; Shim, Jin-Hyung; Jang, Jinah; Kim, Sung-Won; Cho, Dong-Woo

    2015-11-01

    Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self-assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three-dimensional (3D) cell-printed scaffolds using layer-by-layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell-encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell-based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL-alginate gel constructs. PCL-alginate gels containing transforming growth factor-β (TGFβ) showed higher ECM formation. The 3D cell-printed scaffolds of PCL-alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL-alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell-printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. PMID:23349081

  9. Combination therapy with BMP-2 and BMSCs enhances bone healing efficacy of PCL scaffold fabricated using the 3D plotting system in a large segmental defect model.

    PubMed

    Kang, Sun-Woong; Bae, Ji-Hoon; Park, Su-A; Kim, Wan-Doo; Park, Mi-Su; Ko, You-Jin; Jang, Hyon-Seok; Park, Jung-Ho

    2012-07-01

    The three-dimensional (3D) plotting system is a rapidly-developing scaffold fabrication method for bone tissue engineering. It yields a highly porous and inter-connective structure without the use of cytotoxic solvents. However, the therapeutic effects of a scaffold fabricated using the 3D plotting system in a large segmental defect model have not yet been demonstrated. We have tested two hypotheses: whether the bone healing efficacy of scaffold fabricated using the 3D plotting system would be enhanced by bone marrow-derived mesenchymal stem cell (BMSC) transplantation; and whether the combination of bone morphogenetic protein-2 (BMP-2) administration and BMSC transplantation onto the scaffold would act synergistically to enhance bone regeneration in a large segmental defect model. The use of the combined therapy did increase bone regeneration further as compared to that with monotherapy in large segmental bone defects. PMID:22447098

  10. Fabrication and characterization of a 3-D non-homogeneous tissue-like mouse phantom for optical imaging

    NASA Astrophysics Data System (ADS)

    Avtzi, Stella; Zacharopoulos, Athanasios; Psycharakis, Stylianos; Zacharakis, Giannis

    2013-11-01

    In vivo optical imaging of biological tissue not only requires the development of new theoretical models and experimental procedures, but also the design and construction of realistic tissue-mimicking phantoms. However, most of the phantoms available currently in literature or the market, have either simple geometrical shapes (cubes, slabs, cylinders) or when realistic in shape they use homogeneous approximations of the tissue or animal under investigation. The goal of this study is to develop a non-homogeneous realistic phantom that matches the anatomical geometry and optical characteristics of the mouse head in the visible and near-infrared spectral range. The fabrication of the phantom consisted of three stages. Initially, anatomical information extracted from either mouse head atlases or structural imaging modalities (MRI, XCT) was used to design a digital phantom comprising of the three main layers of the mouse head; the brain, skull and skin. Based on that, initial prototypes were manufactured by using accurate 3D printing, allowing complex objects to be built layer by layer with sub-millimeter resolution. During the second stage the fabrication of individual molds was performed by embedding the prototypes into a rubber-like silicone mixture. In the final stage the detailed phantom was constructed by loading the molds with epoxy resin of controlled optical properties. The optical properties of the resin were regulated by using appropriate quantities of India ink and intralipid. The final phantom consisted of 3 layers, each one with different absorption and scattering coefficient (μa,μs) to simulate the region of the mouse brain, skull and skin.

  11. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    PubMed

    Zhang, Hong-Ze; Zhang, Fang-Ting; Zhang, Xiao-Hui; Huang, Dong; Zhou, Ying-Lin; Li, Zhi-Hong; Zhang, Xin-Xiang

    2015-06-16

    Herein, we proposed a portable, easy-to-operate, and antifouling microcapsule array chip for target detection. This prepackaged chip was fabricated by innovative and cost-effective 3D ice printing integrating with photopolymerization sealing which could eliminate complicated preparation of wet chemistry and effectively resist outside contaminants. Only a small volume of sample (2 μL for each microcapsule) was consumed to fulfill the assay. All the reagents required for the analysis were stored in ice form within the microcapsule before use, which guaranteed the long-term stability of microcapsule array chips. Nitrite and glucose were chosen as models for proof of concept to achieve an instant quantitative detection by naked eyes without the need of external sophisticated instruments. The simplicity, low cost, and small sample consumption endowed ice-printing microcapsule array chips with potential commercial value in the fields of on-site environmental monitoring, medical diagnostics, and rapid high-throughput point-of-care quantitative assay. PMID:25970032

  12. Design, Fabrication and Characterization of a Low-Impedance 3D Electrode Array System for Neuro-Electrophysiology

    PubMed Central

    Kusko, Mihaela; Craciunoiu, Florea; Amuzescu, Bogdan; Halitzchi, Ferdinand; Selescu, Tudor; Radoi, Antonio; Popescu, Marian; Simion, Monica; Bragaru, Adina; Ignat, Teodora

    2012-01-01

    Recent progress in patterned microelectrode manufacturing technology and microfluidics has opened the way to a large variety of cellular and molecular biosensor-based applications. In this extremely diverse and rapidly expanding landscape, silicon-based technologies occupy a special position, given their statute of mature, consolidated, and highly accessible areas of development. Within the present work we report microfabrication procedures and workflows for 3D patterned gold-plated microelectrode arrays (MEA) of different shapes (pyramidal, conical and high aspect ratio), and we provide a detailed characterization of their physical features during all the fabrication steps to have in the end a reliable technology. Moreover, the electrical performances of MEA silicon chips mounted on standardized connector boards via ultrasound wire-bonding have been tested using non-destructive electrochemical methods: linear sweep and cyclic voltammetry, impedance spectroscopy. Further, an experimental recording chamber package suitable for in vitro electrophysiology experiments has been realized using custom-design electronics for electrical stimulus delivery and local field potential recording, included in a complete electrophysiology setup, and the experimental structures have been tested on newborn rat hippocampal slices, yielding similar performance compared to commercially available MEA equipments. PMID:23208555

  13. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    PubMed

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were

  14. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing

    PubMed Central

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C–1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C–1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds

  15. Surface Modification and Characterisation of Silk Fibroin Fabric Produced by the Layer-by-Layer Self-Assembly of Multilayer Alginate/Regenerated Silk Fibroin

    PubMed Central

    Shen, Gaotian; Hu, Xingyou; Guan, Guoping; Wang, Lu

    2015-01-01

    Silk-based medical products have a long history of use as a material for surgical sutures because of their desirable mechanical properties. However, silk fibroin fabric has been reported to be haemolytic when in direct contact with blood. The layer-by-layer self-assembly technique provides a method for surface modification to improve the biocompatibility of silk fibroin fabrics. Regenerated silk fibroin and alginate, which have excellent biocompatibility and low immunogenicity, are outstanding candidates for polyelectrolyte deposition. In this study, silk fabric was degummed and positively charged to create a silk fibroin fabric that could undergo self-assembly. The multilayer self-assembly of the silk fibroin fabric was achieved by alternating the polyelectrolyte deposition of a negatively charged alginate solution (pH = 8) and a positively charged regenerated silk fibroin solution (pH = 2). Finally, the negatively charged regenerated silk fibroin solution (pH = 8) was used to assemble the outermost layer of the fabric so that the surface would be negatively charged. A stable structural transition was induced using 75% ethanol. The thickness and morphology were characterised using atomic force microscopy. The properties of the self-assembled silk fibroin fabric, such as the bursting strength, thermal stability and flushing stability, indicated that the fabric was stable. In addition, the cytocompatibility and haemocompatibility of the self-assembled silk fibroin fabrics were evaluated. The results indicated that the biocompatibility of the self-assembled multilayers was acceptable and that it improved markedly. In particular, after the self-assembly, the fabric was able to prevent platelet adhesion. Furthermore, other non-haemolytic biomaterials can be created through self-assembly of more than 1.5 bilayers, and we propose that self-assembled silk fibroin fabric may be an attractive candidate for anticoagulation applications and for promoting endothelial cell

  16. Chemical enhancement of footwear impressions in blood deposited on fabric--evaluating the use of alginate casting materials followed by chemical enhancement.

    PubMed

    Farrugia, Kevin J; NicDaéid, Niamh; Savage, Kathleen A; Bandey, Helen

    2010-12-01

    Most footwear marks made in blood on a surface such as fabric tend to be enhanced in situ rather than physically recovered using a lifting technique prior to enhancement. This work reports on the use of an alginate material to recover the impressed footwear marks made in blood and deposited on a range of fabric types and colours. The lifted marks were then enhanced using acid black 1 and leuco crystal violet with excellent results. This presents a new method for the lifting and recovery of blood impressions in situ from crime scene followed by subsequent mark enhancement of the lifted impression. PMID:21075299

  17. Novel 3D scaffold with enhanced physical and cell response properties for bone tissue regeneration, fabricated by patterned electrospinning/electrospraying.

    PubMed

    Hejazi, Fatemeh; Mirzadeh, Hamid

    2016-09-01

    Developing three dimensional scaffolds mimicking the nanoscale structure of native extracellular matrix is a key parameter in tissue regeneration. In this study, we aimed to introduce a novel 3D structures composed of nanofibers (NF) and micro particles (MP) and compare their efficiency with 2D nanofibrous scaffold. The conventional nanofibrous PCL scaffolds are 2D mats fabricated by the electrospinning technique, whereas the NF/MP and patterned NF/MP PCL scaffolds are three dimensional structures fabricated by a modified electrospinning/electrospraying technique. The mentioned method was carried out by varying the electrospinning solution parameters and use of a metal mesh as the collector. Detailed fabrication process and morphological properties of the fabricated structures is discussed and porosity, pore size and PBS solution absorption value of the prepared structures are reported. Compared with the 2D structure, 3D scaffolds possessed enhanced porosity and pore size which led to the significant increase in their water uptake capacity. In vitro cell experiments were carried out on the prepared structures by the use of MG-63 osteosarcoma cell line. The fabricated 3D structures offered significantly increased cell attachment, spread and diffusion which were confirmed by SEM analysis. In vitro cytocompatibility assessed by MTT colorimetric assay indicated a continuous cell proliferation over 21 days on the innovative 3D structure, while on 2D mat cell proliferation stopped at early time points. Enhanced osteogenic differentiation of the seeded MG-63 cells on 3D scaffold was confirmed by the remarkable ALP activity together with increased and accelerated calcium deposition on this structure compared to 2D mat. Massive and well distributed bone minerals formed on patterned 3D structure were shown by EDX analysis. In comparison between NF/MP quasi-3D and Patterned NF/MP 3D scaffolds, patterned structures proceeded in all of the above properties. As such, the

  18. Fabrication of 4, 5, or 6-fold symmetric 3D photonic structures using single beam and single reflective optical element based holographic lithography

    NASA Astrophysics Data System (ADS)

    George, D.; Lutkenhaus, J.; Lowell, D.; Philipose, U.; Zhang, H.; Poole, Z.; Chen, K.; Lin, Y.

    2015-03-01

    Here we present the holographic fabrication of large area 3D photonic structures using a single reflective optical element (ROE) with a single beam, single exposure process. The ROE consists of a 3D printed plastic support that houses 4, 5, or 6-fold symmetrically arranged reflecting surfaces which redirect a central beam into multiple side beams in an umbrella configuration to be used in multi-beam holography. With a circular polarized beam incident to silicon wafer reflecting surfaces at the Brewster angle, multiple linearly s-polarized side beams are generated. 3D photonic crystal structures of woodpile, Penrose quasi-crystal, and hexagonal symmetry were produced with ROEs that have 4+1, 5+1 and 6+1 beam configurations, respectively. Since the ROE design can be readily changed and implemented for different photonic crystal structures, this fabrication method is more versatile and cost effective than currently comparable single optical methods like prisms and phase masks.

  19. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    PubMed Central

    Yuan, Liang (Leon); Herman, Peter R.

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  20. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    PubMed

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  1. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    NASA Astrophysics Data System (ADS)

    Yuan, Liang (Leon); Herman, Peter R.

    2016-02-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  2. Large Area 2D and 3D Colloidal Photonic Crystals Fabricated by a Roll-to-Roll Langmuir-Blodgett Method.

    PubMed

    Parchine, Mikhail; McGrath, Joe; Bardosova, Maria; Pemble, Martyn E

    2016-06-14

    We present our results on the fabrication of large area colloidal photonic crystals on flexible poly(ethylene terephthalate) (PET) film using a roll-to-roll Langmuir-Blodgett technique. Two-dimensional (2D) and three-dimensional (3D) colloidal photonic crystals from silica nanospheres (250 and 550 nm diameter) with a total area of up to 340 cm(2) have been fabricated in a continuous manner compatible with high volume manufacturing. In addition, the antireflective properties and structural integrity of the films have been enhanced via the use of a second roll-to-roll process, employing a slot-die coating of an optical adhesive over the photonic crystal films. Scanning electron microscopy images, atomic force microscopy images, and UV-vis optical transmission and reflection spectra of the fabricated photonic crystals are analyzed. This analysis confirms the high quality of the 2D and 3D photonic crystals fabricated by the roll-to-roll LB technique. Potential device applications of the large area 2D and 3D colloidal photonic crystals on flexible PET film are briefly reviewed. PMID:27218474

  3. SU-E-J-49: Design and Fabrication of Custom 3D Printed Phantoms for Radiation Therapy Research and Quality Assurance

    SciTech Connect

    Jenkins, C; Xing, L

    2015-06-15

    Purpose The rapid proliferation of affordable 3D printing techniques has enabled the custom fabrication of items ranging from paper weights to medical implants. This study investigates the feasibility of utilizing the technology for developing novel phantoms for use in radiation therapy quality assurance (QA) procedures. Methods A phantom for measuring the geometric parameters of linear accelerator (LINAC) on-board imaging (OBI) systems was designed using SolidWorks. The design was transferred to a 3D printer and fabricated using a fused deposition modeling (FDM) technique. Fiducials were embedded in the phantom by placing 1.6 mm diameter steel balls in predefined holes and securing them with silicone. Several MV and kV images of the phantom were collected and the visibility and geometric accuracy were evaluated. A second phantom, for use in the experimental evaluation of a high dose rate (HDR) brachytherapy dosimeter, was designed to secure several applicator needles in water. The applicator was fabricated in the same 3D printer and used for experiments. Results The general accuracy of printed parts was determined to be 0.1 mm. The cost of materials for the imaging and QA phantoms were $22 and $5 respectively. Both the plastic structure and fiducial markers of the imaging phantom were visible in MV and kV images. Fiducial marker locations were determined to be within 1mm of desired locations, with the discrepancy being attributed to the fiducial attachment process. The HDR phantom secured the applicators within 0.5 mm of the desired locations. Conclusion 3D printing offers an inexpensive method for fabricating custom phantoms for use in radiation therapy quality assurance. While the geometric accuracy of such parts is limited compared to more expensive methods, the phantoms are still highly functional and provide a unique opportunity for rapid fabrication of custom phantoms for use in radiation therapy QA and research.

  4. Microfluidic vascular channels in gels using commercial 3D printers

    NASA Astrophysics Data System (ADS)

    Selvaganapathy, P. Ravi; Attalla, Rana

    2016-03-01

    This paper details the development of a three dimensional (3D) printing system with a modified microfluidic printhead used for the generation of complex vascular tissue scaffolds. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can easily be patterned using 3Dbioprinting techniques. This microfluidic design allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks.

  5. Fabrication of 3D Printed Metal Structures by Use of High-Viscosity Cu Paste and a Screw Extruder

    NASA Astrophysics Data System (ADS)

    Hong, Seongik; Sanchez, Cesar; Du, Hanuel; Kim, Namsoo

    2015-03-01

    Three-dimensional (3D) printing is an important, rapidly growing industry. However, traditional 3D printing technology has problems with some materials. To solve the problem of the limited number of 3D-printable materials, high-viscosity materials and a new method for 3D printing were investigated. As an example of a high-viscosity material, Cu paste was synthesized and a screw extruder printer was developed to print the paste. As a fundamental part of the research, the viscosity of the Cu paste was measured for different Cu content. The viscosity of the paste increased with increasing Cu content. To print high-viscosity Cu paste, printing conditions were optimized. 3D structures were printed, by use of an extruder and high-viscosity metal paste with appropriate printing conditions, and then heat treated. After sintering, however, approximately 75% shrinkage of the final product was observed. To achieve less shrinkage, the packing factor of the Cu paste was increased by adding more Cu particles. The shrinkage factor decreased as the packing factor increased, and the size of final product was 77% of that expected.

  6. Coaxial nozzle-assisted 3D bioprinting with built-in microchannels for nutrients delivery.

    PubMed

    Gao, Qing; He, Yong; Fu, Jian-zhong; Liu, An; Ma, Liang

    2015-08-01

    This study offers a novel 3D bioprinting method based on hollow calcium alginate filaments by using a coaxial nozzle, in which high strength cell-laden hydrogel 3D structures with built-in microchannels can be fabricated by controlling the crosslinking time to realize fusion of adjacent hollow filaments. A 3D bioprinting system with a Z-shape platform was used to realize layer-by-layer fabrication of cell-laden hydrogel structures. Curving, straight, stretched or fractured filaments can be formed by changes to the filament extrusion speed or the platform movement speed. To print a 3D structure, we first adjusted the concentration and flow rate of the sodium alginate and calcium chloride solution in the crosslinking process to get partially crosslinked filaments. Next, a motorized XY stages with the coaxial nozzle attached was used to control adjacent hollow filament deposition in the precise location for fusion. Then the Z stage attached with a Z-shape platform moved down sequentially to print layers of structure. And the printing process always kept the top two layers fusing and the below layers solidifying. Finally, the Z stage moved down to keep the printed structure immersed in the CaCl2 solution for complete crosslinking. The mechanical properties of the resulting fused structures were investigated. High-strength structures can be formed using higher concentrations of sodium alginate solution with smaller distance between adjacent hollow filaments. In addition, cell viability of this method was investigated, and the findings show that the viability of L929 mouse fibroblasts in the hollow constructs was higher than that in alginate structures without built-in microchannels. Compared with other bioprinting methods, this study is an important technique to allow easy fabrication of lager-scale organs with built-in microchannels. PMID:26004235

  7. Fabrication of homogeneously cross-linked, functional alginate microcapsules validated by NMR-, CLSM- and AFM-imaging.

    PubMed

    Zimmermann, H; Hillgärtner, M; Manz, B; Feilen, P; Brunnenmeier, F; Leinfelder, U; Weber, M; Cramer, H; Schneider, S; Hendrich, C; Volke, F; Zimmermann, U

    2003-05-01

    Cross-linked alginate microcapsules of sufficient mechanical strength can immunoisolate cells for the long-term treatment of hormone and other deficiency diseases in human beings. However, gelation of alginate by external Ba(2+) (or other divalent cations) produces non-homogeneous cross-linking of the polymeric mannuronic (M) and guluronic (G) acid chains. The stability of such microcapsules is rather limited. Here, we show that homogeneous cross-linking can be achieved by injecting BaCl(2) crystals into alginate droplets before they come into contact with external BaCl(2). The high effectiveness of this crystal gun method is demonstrated by confocal laser scanning microscopy and by advanced nuclear magnetic resonance imaging. Both techniques gave clear-cut evidence that homogeneous cross-linkage throughout the microcapsule is only obtained with simultaneous internal and external gelation. Atomic force microscopy showed a very smooth surface topography for microcapsules made by the crystal gun method, provided that excess Ba(2+) ions were removed immediately after gelation. In vitro experiments showed greatly suppressed swelling for crystal gun microcapsules. Even alginate extracted from Lessonia nigrescens (highly biocompatible) yielded microcapsules with long-term mechanical stability not hitherto possible. Encapsulation of rat islets, human monoclonal antibodies secreting hybridoma cells and murine mesenchymal stem cells transfected with cDNA encoding for bone morphogenetic protein (BMP-4) revealed that injection of BaCl(2) crystals has no adverse side effects on cell viability and function. However, the release of low-molecular weight factors (such as insulin) may be delayed when using alginate concentrations in the usual range. PMID:12628829

  8. Electrical manipulation of biological samples in glass-based electrofluidics fabricated by 3D femtosecond laser processing

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2014-03-01

    Electrical manipulation of biological samples using glass-based electrofluidics fabricated by femtosecond laser, in which the microfluidic structures are integrated with microelectric components, is presented. Electro-orientation of movement of living cells with asymmetric shapes such as Euglena gracilis of aquatic microorganisms in microfluidic channels is demonstrated using the fabricated electrofluidics. By integrating the properly designed microelectrodes into microfluidic channels, the orientation direction of Euglena cells can be well controlled.

  9. Engineering Multi-scale Electrospun Structure for Integration into Architected 3-D Nanofibers for Cimex Annihilation: Fabrication and Mechanism Study

    NASA Astrophysics Data System (ADS)

    He, Shan; Zhang, Linxi; Liu, Ying; Rafailovich, Miriam; Garcia Center for Polymers at Engineered Interfaces Team

    In this study, engineered electrospun scaffolds with fibers oriented with designed curvature in three dimensions (3D) including the looped structure were developed based on the principle of electrostatic repulsion. Here we illustrate that 3D electrospun recycled polystyrene fibers could closely mimic the unique architectures of multi-direction and multi-layer nano-spiderweb. In contrast to virgin PS, the recycled PS (Dart Styrofoam) are known to contain zinc stearate which acts as a surfactant resulting in higher electrical charge and larger fiber curvature, hence, lower modulus. The surfactant, which is known to decrease the surface tension, may have also been effective at decreasing the confinement of the PS, where chain stretching was shown to occur, in response to the high surface tension at the air interface. Three dimensional flexible architecture with complex structures are shown to be necessary in order to block the motion of Cimex lectularius. Here we show how an engineered electrospun network of surfactant modified polymer fibers with calculated dimensions can be used to immobilize the insects. The mechanical response of the fibers has to be specifically tailored so that it is elastically deformed, without fracturing or flowing. Carefully controlling and tailoring the electrospinning parameters we can now utilize architected 3D nanofiber to create an environmental-friendly Cimex immobilization device which can lead to annihilation solution for all the other harmful insects.

  10. 3D porous and ultralight carbon hybrid nanostructure fabricated from carbon foam covered by monolayer of nitrogen-doped carbon nanotubes for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    He, Shuijian; Hou, Haoqing; Chen, Wei

    2015-04-01

    3D porous and self-supported carbon hybrids are promising electrode materials for supercapacitor application attributed to their prominent properties such as binder-free electrode fabrication process, excellent electric conductivity and high power density etc. We present here a facile chemical vapor deposition method to fabricate a novel 3D flexible carbon hybrid nanostructure by growing a monolayer of nitrogen-doped carbon nanotubes on the skeleton of carbon foam (N-CNTs/CF) with Fe nanoparticle as catalyst. With such 3D porous, flexible and ultralight carbon nanostructure as binder-free electrode material, large surface area is available and fast ionic transport is facilitated. Moreover, the carbon-based network can provide excellent electronic conductivity. The electrochemical studies demonstrate that the supercapacitor constructed from the N-CNTs/CF hybrid exhibit high power density of 69.3 kW kg-1 and good stability with capacitance retention ration above 95% after cycled at 50 A g-1 for 5000 cycles. Therefore, the prepared porous N-CNTs/CF nanostructure is expected to be a type of excellent electrode material for electrical double layer capacitors.

  11. Hierarchical fabrication of heterojunctioned SrTiO3/TiO2 nanotubes on 3D microporous Ti substrate with enhanced photocatalytic activity and adhesive strength

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Yin, Lu; Zha, Kang; Li, Huirong; Liu, Zhiyuan; Wang, Jianxin; Duan, Ke; Feng, Bo

    2016-03-01

    Recently, construction of three-dimensional (3D) architecture and design of heterostructure have been proved to be two important approaches for improving photocatalytic (PC) properties of TiO2-based catalysts. In this work, a 3D microporous surface on Ti substrate (MPT) was prepared by simple acid etching. Then, heterojunctioned SrTiO3/TiO2 nanotubes with dominant {001} facets of anatase TiO2were successfully fabricated on MPT by combining anodization with hydrothermal treatment. The 3D microporous-patterned SrTiO3/TiO2 nanotubes heterojunction shows significantly enhanced photo-current density and ∼200% improved PC effect in degradation of Rhodamine B owing to its higher specific surface area, stronger light-harvesting ability and positive heterojunction effect in comparison with TiO2 nanotubes formed on flat Ti substrate. Moreover, the 3D microporous structure on Ti substrate improved the adhesive strength between the nanotubes layer and Ti substrate, which can be ascribed to the effective release of internal stress. Therefore, this present strategy is expected to expand the application of TiO2-based catalysts in many fields which require excellent PC properties and mechanical stability.

  12. Fabrication of Highly Stretchable Conductors Based on 3D Printed Porous Poly(dimethylsiloxane) and Conductive Carbon Nanotubes/Graphene Network.

    PubMed

    Duan, Shasha; Yang, Ke; Wang, Zhihui; Chen, Mengting; Zhang, Ling; Zhang, Hongbo; Li, Chunzhong

    2016-01-27

    The combination of carbon nanomaterial with three-dimensional (3D) porous polymer substrates has been demonstrated to be an effective approach to manufacture high-performance stretchable conductive materials (SCMs). However, it remains a challenge to fabricate 3D-structured SCMs with outstanding electrical conductivity capability under large strain in a facile way. In this work, the 3D printing technique was employed to prepare 3D porous poly(dimethylsiloxane) (O-PDMS) which was then integrated with carbon nanotubes and graphene conductive network and resulted in highly stretchable conductors (OPCG). Two types of OPCG were prepared, and it has been demonstrated that the OPCG with split-level structure exhibited both higher electrical conductivity and superior retention capability under deformations, which was illustrated by using a finite element method. The specially designed split-level OPCG is capable of sustaining both large strain and repeated deformations showing huge potential in the application of next-generation stretchable electronics. PMID:26713456

  13. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature

    PubMed Central

    Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

    2016-01-01

    An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

  14. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair

    NASA Astrophysics Data System (ADS)

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-01

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds.

  15. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair.

    PubMed

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-12

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds. PMID:26758780

  16. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature.

    PubMed

    Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

    2016-01-01

    An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

  17. Fabrication of high sensitivity 3D nanoSQUIDs based on a focused ion beam sculpting technique

    NASA Astrophysics Data System (ADS)

    De Leo, Natascia; Fretto, Matteo; Lacquaniti, Vincenzo; Granata, Carmine; Vettoliere, Antonio

    2016-09-01

    In this paper a nanofabrication process, based on a focused ion beam (FIB) nanosculpting technique, for high sensitivity three-dimensional nanoscale superconducting quantum interference devices (nanoSQUIDs) is reported. The crucial steps of the fabrication process are described, as are some peculiar features of the superconductor–normal metal–insulator–superconductor (SNIS) Josephson junctions, which may useful for applications in cryocooler systems. This fabrication procedure is employed to fabricate sandwich nanojunctions and high sensitivity nanoSQUIDs. Specifically, the superconductive nanosensors have a rectangular loop of 1 × 0.2–0.4 μm2 interrupted by two square Nb/Al–AlO x /Nb SNIS Josephson junctions with side lengths of 0.3 μm. The characterization of a typical nanoSQUID has been carried out and a spectral density of magnetic flux noise as low as 0.8 μΦ0 Hz–1/2 has been measured.

  18. Facile fabrication of poly(L-lactic acid) microsphere-incorporated calcium alginate/hydroxyapatite porous scaffolds based on Pickering emulsion templates.

    PubMed

    Hu, Yang; Ma, Shanshan; Yang, Zhuohong; Zhou, Wuyi; Du, Zhengshan; Huang, Jian; Yi, Huan; Wang, Chaoyang

    2016-04-01

    In this study, we develop a facile one-pot approach to the fabrication of poly(L-lactic acid) (PLLA) microsphere-incorporated calcium alginate (ALG-Ca)/hydroxyapatite (HAp) porous scaffolds based on HAp nanoparticle-stabilized oil-in-water Pickering emulsion templates, which contain alginate in the aqueous phase and PLLA in the oil phase. The emulsion aqueous phase is solidified by in situ gelation of alginate with Ca(2+) released from HAp by decreasing pH with slow hydrolysis of d-gluconic acid δ-lactone (GDL) to produce emulsion droplet-incorporated gels, followed by freeze-drying to form porous scaffolds containing microspheres. The pore structure of porous scaffolds can be adjusted by varying the HAp or GDL concentration. The compressive tests show that the increase of HAp or GDL concentration is beneficial to improve the compressive property of porous scaffolds, while the excessive HAp can lead to the decrease in compressive property. Moreover, the swelling behavior studies display that the swelling ratios of porous scaffolds reduce with increasing HAp or GDL concentration. Furthermore, hydrophobic drug ibuprofen (IBU) and hydrophilic drug bovine serum albumin (BSA) are loaded into the microspheres and scaffold matrix, respectively. In vitro drug release results indicate that BSA has a rapid release while IBU has a sustained release in the dual drug-loaded scaffolds. In vitro cell culture experiments verify that mouse bone mesenchymal stem cells can proliferate on the porous scaffolds well, indicating the good biocompatibility of porous scaffolds. All these results demonstrate that the PLLA microsphere-incorporated ALG-Ca/HAp porous scaffolds have a promising potential for tissue engineering and drug delivery applications. PMID:26774574

  19. Influence of mechanical properties of alginate-based substrates on the performance of Schwann cells in culture.

    PubMed

    Ning, Liqun; Xu, Yitong; Chen, Xiongbiao; Schreyer, David J

    2016-06-01

    In tissue engineering, artificial tissue scaffolds containing living cells have been studied for tissue repair and regeneration. Notably, the performance of these encapsulated-in-scaffolds cells in terms of cell viability, proliferation, and expression of function during and after the scaffold fabrication process, has not been well documented because of the influence of mechanical, chemical, and physical properties of the scaffold substrate materials. This paper presents our study on the influence of mechanical properties of alginate-based substrates on the performance of Schwann cells, which are the major glial cells of peripheral nervous system. Given the fact that alginate polysaccharide hydrogel has poor cell adhesion properties, in this study, we examined several types of cell-adhesion supplements and found that alginate covalently modified with RGD peptide provided improved cell proliferation and adhesion. We prepared alginate-based substrates for cell culture using varying alginate concentrations for altering their mechanical properties, which were confirmed by compression testing. Then, we examined the viability, proliferation, morphology, and expression of the extracellular matrix protein laminin of Schwann cells that were seeded on the surface of alginate-based substrates (or 2D culture) or encapsulated within alginate-based substrates (3D cultures), and correlated the examined cell performance to the alginate concentration (or mechanical properties) of hydrogel substrates. Our findings suggest that covalent attachment of RGD peptide can improve the success of Schwann cell encapsulation within alginate-based scaffolds, and provide guidance for regulating the mechanical properties of alginate-based scaffolds containing Schwann cells for applications in peripheral nervous system regeneration and repair. PMID:27012482

  20. Contrast Enhancement of MicroCT Scans to Aid 3D Modelling of Carbon Fibre Fabric Composites

    NASA Astrophysics Data System (ADS)

    Djukic, Luke P.; Pearce, Garth M.; Herszberg, Israel; Bannister, Michael K.; Mollenhauer, David H.

    2013-12-01

    This paper presents a methodology for volume capture and rendering of plain weave and multi-layer fabric meso-architectures within a consolidated, cured laminate. Micro X-ray Computed Tomography (MicroCT) is an excellent tool for the non-destructive visualisation of material microstructures however the contrast between tows and resin is poor for carbon fibre composites. Firstly, this paper demonstrates techniques to improve the contrast of the microCT images by introducing higher density materials such as gold, iodine and glass into the fabric. Two approaches were demonstrated to be effective for enhancing the differentiation between the tows in the reconstructed microCT visualisations. Secondly, a method of generating three-dimensional volume models of woven composites using microCT scan data is discussed. The process of generating a model is explained from initial manufacture with the aid of an example plain weave fabric. These methods are to be used in the finite element modelling of three-dimensional fabric preforms in future work.

  1. Fabrication and characterization of a magnetic micro-actuator based on deformable Fe-doped PDMS artificial cilium using 3D printing

    NASA Astrophysics Data System (ADS)

    Liu, Fengli; Alici, Gursel; Zhang, Binbin; Beirne, Stephen; Li, Weihua

    2015-03-01

    This paper proposes the use of a 3D extrusion printer to fabricate artificial magnetic cilium. The cilia are fabricated using polydimethylsiloxane (PDMS) doped with iron particles so that they remain slender and flexible. They can be driven by a magnetic field to closely mimic the behaviour of biological cilia. Doping iron particles to the polymers has already been done; however, to the best of our knowledge, printing such active and soft magnetic structures has not. The existing methods for manufacturing magnetic polymeric structures are complex and difficult to use for the fabrication of micro-sized high-aspect-ratio cilia. The 3D printing technique we propose here is simple and inexpensive compared to previously suggested fabrication methods. In this study, free-standing magnetic PDMS cilia were fabricated in different sizes up to 5 mm in length and 1 mm in width. The stress-strain curves of the PDMS cilia were experimentally obtained to quantify the effect of the concentration of the iron particles on the modulus of elasticity of the cilia. The higher the iron concentration, the higher the modulus of elasticity. We have quantified the characteristics of the cilia made of 40% w/w iron particles in PDMS. A single cilium (5 × 1 × 0.0035 mm) can output up to 27 μN blocking force under a magnetic field of 160 mT. These cilia can be used as a mixer in lap-on-chip applications and as the anchoring and propulsion legs of endoscopic capsule robots operating within the gastrointestinal tract of humans. Analytical expressions estimating the blocking force are established and compared with the experimental results.

  2. Effect of cold plasma pre-treatment on photocatalytic activity of 3D fabric loaded with nano-photocatalysts: Response surface methodology

    NASA Astrophysics Data System (ADS)

    Ghoreishian, Seyed Majid; Badii, Khashayar; Norouzi, Mohammad; Malek, Kaveh

    2016-03-01

    In this study, the physico-chemical effects occasioned by the cold plasma discharge (CPD) on the photo-decolorization of Reactive Orange 16 (RO16) by 3D fabrics (spacer fabrics) loaded with ZnO:TiO2 nano-photocatalysts (nphs) were optimized via response surface methodology (RSM). CPD was employed to improve the surface characteristics of the spacer fabrics for nphs loading. Surface morphology and color variation were studied utilizing scanning electron microscopy (SEM) and CIE-Lab system, respectively. The effect of CPD on the wetting ability of the spacer fabrics was examined using dynamic adsorption measurement (DAM). Also, X-ray fluorescence (XRF) was utilized to investigate the durability of the nphs on the spacer fabrics. All the experiments were implemented in a Box-Behnken design (BBD) with three independent variables (CPD treatment time, dye concentration and irradiation time) in order to optimize the decolorization of RO16. The anticipated values of the decolorization efficiency were found to be in excellent agreement with the experimental values (R2 = 0.9996, Adjusted R2 = 0.9992). The kinetic analysis demonstrated that the photocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. In conclusion, this heterogeneous photocatalytic process is capable of decolorizing and mineralizing azoic reactive dye in textile wastewater. Moreover, the results confirmed that RSM based on the BBD was a suitable method to optimize the operating conditions of RO16 degradation.

  3. Hierarchical graphene nanocones over 3D platform of carbon fabrics: A route towards fully foldable graphene based electron source

    NASA Astrophysics Data System (ADS)

    Maiti, Uday N.; Maiti, Soumen; Das, Nirmalya S.; Chattopadhyay, Kalyan K.

    2011-10-01

    A three dimensional field emitter comprising hierarchical nanostructures of graphene over flexible fabric substrate is presented. The nanostructuring is realized through plasma treatment of graphene, coaxially deposited over individual carbon fiber by means of simple aqueous phase electrophoretic deposition technique. Hierarchical graphene nanocone, acting as a cold electron emitter, exhibits outstanding electron emission performance with a turn-on field as low as 0.41 V μm-1 and a threshold field down to 0.81 V μm-1. Electric field modification around the special woven like geometry of the underlying base fabric substrate serves as the booster to the nanostructured graphene related field amplification at the electron emission site. Superb robustness in the emission stability can be attributed to suppressed joule heating on behalf of higher inborn accessible surface area of graphene nanocone as well as excellent electrical and thermal conductivity of both the graphene and carbon fabrics. Superior flexibility of this high-performance graphene based emitter ensures their potential use in completely foldable and wearable field emission devices.A three dimensional field emitter comprising hierarchical nanostructures of graphene over flexible fabric substrate is presented. The nanostructuring is realized through plasma treatment of graphene, coaxially deposited over individual carbon fiber by means of simple aqueous phase electrophoretic deposition technique. Hierarchical graphene nanocone, acting as a cold electron emitter, exhibits outstanding electron emission performance with a turn-on field as low as 0.41 V μm-1 and a threshold field down to 0.81 V μm-1. Electric field modification around the special woven like geometry of the underlying base fabric substrate serves as the booster to the nanostructured graphene related field amplification at the electron emission site. Superb robustness in the emission stability can be attributed to suppressed joule heating on

  4. Fabrication of 3D hierarchical MoS₂/polyaniline and MoS₂/C architectures for lithium-ion battery applications.

    PubMed

    Hu, Lianren; Ren, Yumei; Yang, Hongxia; Xu, Qun

    2014-08-27

    In this work, three-dimensional (3D) hierarchical MoS2/polyaniline (PANI) nanoflowers were successfully fabricated via a simple hydrothermal method. The crystal structure and morphology of the MoS2/PANI nanoflowers were characterized by SEM, TEM, XRD, XPS, and FT-IR spectra, revealing that the nanoflowers were composed of ultrathin nanoplates which consisted of few-layered MoS2 nanosheets with enlarged interlayer distance of the (002) plane and PANI. The excellent electrochemical performance of the 3D hierarchical MoS2/PANI nanoflowers was demonstrated. Further 3D hierarchical MoS2/C nanoflowers can be prepared conveniently by annealing the MoS2/PANI sample in a N2 atmosphere at 500 °C for 4 h. The obtained MoS2/C sample exhibited more excellent electrochemical performance due to its excellent electronic conductivity resulting from the close integration of MoS2 nanosheets with carbon matrix. High reversible capacity of 888.1 mAh g(-1) with the Coulombic efficiency maintained at above 90% from the first cycle were achieved at a current density of 100 mA g(-1). Even at a current density of 1000 mA g(-1), the reversible capacity of the MoS2/C sample could be retained at 511 mAh g(-1). The excellent electrochemical performance of these two samples could be attributed to the combined action of enlarged interlayer distance of the ultrathin MoS2 nanosheets, 3D architectures, hierarchical structures, and conductive material. Thus, these 3D hierarchical nanoflowers are competent as promising anode materials for high-performance lithium-ion batteries. PMID:25100439

  5. Development of an Efficient Quasi-3D Microfluidic Flow Model and Fabrication and Characterization of an All-PDMS Opto-Microfluidic Flow Cytometer

    NASA Astrophysics Data System (ADS)

    Islam, Md Zahurul

    In this thesis, development of a novel microfluidic flow model, and, fabrication and testing of microfluidic cytometer for potential cell detection and sorting applications are described. The model is formulated by decomposing the flow profile along the height of microfluidic device into a Fourier series that converts the 3D flow equations into a series of coupled 2D equations and is applicable to planar microfluidic devices only. It is validated against the analytical solution for flow in a straight rectangular channel and the full 3D solution of a commercial Navier-Stokes solver for flow in a T-channel. Comparable accuracy to the full 3D numerical solution is achieved by using only three Fourier terms with significant decrease in computation time. The model is also extended to the problems with time-varying boundary conditions. We fabricated two first generation miniaturized cytometer prototypes and used them for preliminary proof-of-concepts experiments. They were built by cutting fluidic channels into two different polymer materials and bonding them between two standard glass slides with epoxy and fusion bonding. We fabricated a second generation of flow cytometer chip consisting of an integrated 2D hydrodynamic focusing system, solid-core optical waveguides and a hydrodynamic side-flow switching system on an all-PDMS platform. Optical propagation losses of the integrated waveguides and signal-to-noise ratio (SNR) of its detection system were characterized. The propagation losses were found to be 1.6 and 1.5 dB/cm for the green and red light, respectively. Detection of fluorescent signal through the waveguide yielded improved SNR than the conventional method of under-chip detection. Fluid flow speeds were estimated from volumetric flow measurements and fluorescent particle tracking experiments and the width of the hydrodynamically focused stream was extracted from microscope flow images. The results were compared to the simulation values obtained from the Q3D

  6. Flexible Fabrication of Shape-Controlled Collagen Building Blocks for Self-Assembly of 3D Microtissues.

    PubMed

    Zhang, Xu; Meng, Zhaoxu; Ma, Jingyun; Shi, Yang; Xu, Hui; Lykkemark, Simon; Qin, Jianhua

    2015-08-12

    Creating artificial tissue-like structures that possess the functionality, specificity, and architecture of native tissues remains a big challenge. A new and straightforward strategy for generating shape-controlled collagen building blocks with a well-defined architecture is presented, which can be used for self-assembly of complex 3D microtissues. Collagen blocks with tunable geometries are controllably produced and released via a membrane-templated microdevice. The formation of functional microtissues by embedding tissue-specific cells into collagen blocks with expression of specific proteins is described. The spontaneous self-assembly of cell-laden collagen blocks into organized tissue constructs with predetermined configurations is demonstrated, which are largely driven by the synergistic effects of cell-cell and cell-matrix interactions. This new strategy would open up new avenues for the study of tissue/organ morphogenesis, and tissue engineering applications. PMID:25920010

  7. Engineering alginate as bioink for bioprinting.

    PubMed

    Jia, Jia; Richards, Dylan J; Pollard, Samuel; Tan, Yu; Rodriguez, Joshua; Visconti, Richard P; Trusk, Thomas C; Yost, Michael J; Yao, Hai; Markwald, Roger R; Mei, Ying

    2014-10-01

    Recent advances in three-dimensional (3-D) printing offer an excellent opportunity to address critical challenges faced by current tissue engineering approaches. Alginate hydrogels have been used extensively as bioinks for 3-D bioprinting. However, most previous research has focused on native alginates with limited degradation. The application of oxidized alginates with controlled degradation in bioprinting has not been explored. Here, a collection of 30 different alginate hydrogels with varied oxidation percentages and concentrations was prepared to develop a bioink platform that can be applied to a multitude of tissue engineering applications. The authors systematically investigated the effects of two key material properties (i.e. viscosity and density) of alginate solutions on their printabilities to identify a suitable range of material properties of alginates to be applied to bioprinting. Further, four alginate solutions with varied biodegradability were printed with human adipose-derived stem cells (hADSCs) into lattice-structured, cell-laden hydrogels with high accuracy. Notably, these alginate-based bioinks were shown to be capable of modulating proliferation and spreading of hADSCs without affecting the structure integrity of the lattice structures (except the highly degradable one) after 8days in culture. This research lays a foundation for the development of alginate-based bioink for tissue-specific tissue engineering applications. PMID:24998183

  8. Engineering alginate as bioink for bioprinting

    PubMed Central

    Jia, Jia; Richards, Dylan J.; Pollard, Samuel; Tan, Yu; Rodriguez, Joshua; Visconti, Richard P.; Trusk, Thomas C.; Yost, Michael J.; Yao, Hai; Markwald, Roger R.; Mei, Ying

    2015-01-01

    Recent advances in 3D printing offer an excellent opportunity to address critical challenges faced by current tissue engineering approaches. Alginate hydrogels have been extensively utilized as bioinks for 3D bioprinting. However, most previous research has focused on native alginates with limited degradation. The application of oxidized alginates with controlled degradation in bioprinting has not been explored. Here, we prepared a collection of 30 different alginate hydrogels with varied oxidation percentages and concentrations to develop a bioink platform that can be applied to a multitude of tissue engineering applications. We systematically investigated the effects of two key material properties (i.e. viscosity and density) of alginate solutions on their printabilities to identify a suitable range of material properties of alginates to be applied to bioprinting. Further, four alginate solutions with varied biodegradability were printed with human adipose-derived stem cells (hADSCs) into lattice-structured, cell-laden hydrogels with high accuracy. Notably, these alginate-based bioinks were shown to be capable of modulating proliferation and spreading of hADSCs without affecting structure integrity of the lattice structures (except the highly degradable one) after 8 days in culture. This research lays a foundation for the development of alginate-based bioink for tissue-specific tissue engineering applications. PMID:24998183

  9. Spring Characteristics of Circular Arc Shaped 3D Micro-cantilevers Fabricated Using III-V Semiconductor Strain-driven Bending Process

    NASA Astrophysics Data System (ADS)

    Sasaki, T. K.; Iwase, H.; Wang, J.; Akabori, M.; Yamada, S.

    2011-12-01

    We have investigated the characteristics of the circular arc shaped 3D micro-cantilever. The cantilever was fabricated using strain driven self-bending process based on the epitaxial growth. The arc shape can be used as the spring element in the various micro electro- mechanical- system (MEMS) applications. In this work, we focused on the force-deflection relationships, which would give the spring constant of the arc spring. In the case of the arc spring, spring constant depends on the dimensional parameters such as width, thickness and curvature radius. From the dependence of curvature radius on width, there seems no stress relaxation in width direction (transverse to deformation direction). Moreover, the measured spring constants of the fabricated cantilevers were also larger than the estimated ones from the curvature radius. The discrepancy indicates a possibility of stiffness enhancement of the circular arc shaped cantilevers.

  10. Fabrication of PDMS (poly-dimethyl siloxane) molding and 3D structure by two-photon absorption induced by an ultrafast laser

    NASA Astrophysics Data System (ADS)

    Yi, Shin Wook; Lee, Seong Ku; Cho, Mi Jung; Kong, Hong Jin; Yang, Dong-Yol; Park, Sang-hu; Lim, Tae-woo; Kim, Ran Hee; Lee, Kwang-Sup

    2004-12-01

    Multi-photon absorption phenomena induced by ultra fast laser have been considered for many applications of microfabrications such as metal ablation, glass etching and photopolymerization. Among the applications, the photopolymerization by two-photon absorption (TPA) has been regarded as a new microfabricating method. It is possible to be used in photo mask correcting, diffractive optical element and micro machining. The TPA photopolymerization is made possible to fabricate a complicated three dimensional structure which the conventional photomask technology has not been able to make. Furthermore the TPA photopolymerization process applied to a two dimensional structure fabrication may take shorter time than the old process since the absence of etching and deposition processes. Recently we have made a simple 3D structure and applied the technique to PDMS(poly-dimethyl siloxane) molding.

  11. The design and fabrication of a toroidally continuous cryocondensation pump for the D3-D advanced divertor

    NASA Astrophysics Data System (ADS)

    Smith, J. P.; Baxi, C. B.; Reis, E.; Schaffer, M. J.; Schaubel, K. M.; Menon, M. M.

    1991-11-01

    A cryocondensation pump will be installed in the baffle chamber of the DIII-D tokamak in the spring of 1992. The design is complete and fabrication of this pump is in progress. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long, in the lower outer corner of the vacuum vessel interior. It consists of a 1 m(exp 2) liquid helium cooled surface surrounded by a liquid nitrogen cooled shield to limit the heat load on the helium cooled surface. The stainless steel liquid nitrogen shell has a copper coating on it to enhance thermal conductivity, but the coating is broken to keep the toroidal electrical resistance high. The liquid nitrogen cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. The whole pump is supported off the water cooled vacuum vessel wall. Key design considerations were: how to accommodate the temperature differences between the various components, developing low heat leak paths for the various supports, and maintaining electrical insulation in a low pressure environment in the presence of induced voltage spikes. A single point ground for the system was used to limit disruption induced currents and the resulting electro-mechanical forces on the pump. A testing program was used to develop coating techniques to enhance heat transfer and emissivity of the various surfaces. Fabrication tests were done to determine the best method of attaching the liquid nitrogen flow tubes to their shield surfaces. A prototype sector of the pump was built to verify fabrication and assembly techniques.

  12. Image-based analysis of the internal microstructure of bone replacement scaffolds fabricated by 3D printing

    NASA Astrophysics Data System (ADS)

    Irsen, Stephan H.; Leukers, Barbara; Bruckschen, Björn; Tille, Carsten; Seitz, Hermann; Beckmann, Felix; Müller, Bert

    2006-08-01

    Rapid Prototyping and especially the 3D printing, allows generating complex porous ceramic scaffolds directly from powders. Furthermore, these technologies allow manufacturing patient-specific implants of centimeter size with an internal pore network to mimic bony structures including vascularization. Besides the biocompatibility properties of the base material, a high degree of open, interconnected porosity is crucial for the success of the synthetic bone graft. Pores with diameters between 100 and 500 μm are the prerequisite for vascularization to supply the cells with nutrients and oxygen, because simple diffusion transport is ineffective. The quantification of porosity on the macro-, micro-, and nanometer scale using well-established techniques such as Hg-porosimetry and electron microscopy is restricted. Alternatively, we have applied synchrotron-radiation-based micro computed tomography (SRμCT) to determine the porosity with high precision and to validate the macroscopic internal structure of the scaffold. We report on the difficulties in intensity-based segmentation for nanoporous materials but we also elucidate the power of SRμCT in the quantitative analysis of the pores at the different length scales.

  13. 3D Printing, Additive Manufacturing, and Solid Freeform Fabrication: The Technologies of the Past, Present and Future

    NASA Astrophysics Data System (ADS)

    Beaman, Joseph

    2015-03-01

    Starting in the late 1980's, several new technologies were created that have the potential to revolutionize manufacturing. These technologies are, for the most part, additive processes that build up parts layer by layer. In addition, the processes that are being touted for hard-core manufacturing are primarily laser or e-beam based processes. This presentation gives a brief history of Additive Manufacturing and gives an assessment for these technologies. These technologies initially grew out of a commercial need for rapid prototyping. This market has a different requirement for process and quality control than traditional manufacturing. The relatively poor process control of the existing commercial Additive Manufacturing equipment is a vestige of this history. This presentation discusses this history and improvements in quality over time. The emphasis will be on Additive Manufacturing processes that are being considered for direct manufacturing, which is a different market than the 3D Printing ``Makerbot'' market. Topics discussed include past and present machine sensors, materials, and operational methods that were used in the past and those that are used today to create manufactured parts. Finally, a discussion of new methods and future directions of AM is presented.

  14. Mechanical and in vitro performance of apatite-wollastonite glass ceramic reinforced hydroxyapatite composite fabricated by 3D-printing.

    PubMed

    Suwanprateeb, J; Sanngam, R; Suvannapruk, W; Panyathanmaporn, T

    2009-06-01

    In situ hydroxyapatite/apatite-wollastonite glass ceramic composite was fabricated by a three dimensional printing (3DP) technique and characterized. It was found that the as-fabricated mean green strength of the composite was 1.27 MPa which was sufficient for general handling. After varying sintering temperatures (1050-1300 degrees C) and times (1-10 h), it was found that sintering at 1300 degrees C for 3 h gave the greatest flexural modulus and strength, 34.10 GPa and 76.82 MPa respectively. This was associated with a decrease in porosity and increase in densification ability of the composite resulting from liquid phase sintering. Bioactivity tested by soaking in simulated body fluid (SBF) and In Vitro toxicity studies showed that 3DP hydroxyapatite/A-W glass ceramic composite was non-toxic and bioactive. A new calcium phosphate layer was observed on the surface of the composite after soaking in SBF for only 1 day while osteoblast cells were able to attach and attain normal morphology on the surface of the composite. PMID:19225870

  15. The fabrication of foam-like 3D mesoporous NiO-Ni as anode for high performance Li-ion batteries

    SciTech Connect

    Huang, Peng; Zhang, Xin; Wei, Jumeng; Pan, Jiaqi; Sheng, Yingzhou; Feng, Boxue

    2015-03-15

    Graphical abstract: Foam-like 3 dimensional (3D) mesoporous NiO on 3D micro-porous Ni was fabricated. - Highlights: • We prepare NiO-Ni foam composite via hydrothermal etching and subsequent annealing. • The NiO exhibits novel foam-like 3D mesoporous architecture. • The NiO-Ni anode shows good cycle stability. - Abstract: Foam-like three dimensional mesoporous NiO on Ni foam was fabricated via facile hydrothermal etching and subsequent annealing treatment. The porous NiO consists of a large number of nanosheets with mean thickness about 50 nm, among which a large number of mesoscopic pores with size ranges from 100 nm to 1 μm distribute. The electrochemical performance of the as-prepared NiO-Ni as anode for lithium ion battery was studied by conventional charge/discharge test, which shows excellent cycle stability and rate capability. It exhibits initial discharge and charge capacities of 979 and 707 mA h g{sup −1} at a charge/discharge rate of 0.7 C, which maintain of 747 and 738 mA h g{sup −1} after 100 cycles. Even after 60 cycles at various rates from 0.06 to 14 C, the 10th discharge and charge capacities of the NiO-Ni electrode can revert to 699 and 683 mA h g{sup −1} when lowering the charge/discharge rate to 0.06 C.

  16. WE-F-16A-02: Design, Fabrication, and Validation of a 3D-Printed Proton Filter for Range Spreading

    SciTech Connect

    Remmes, N; Courneyea, L; Corner, S; Beltran, C; Kemp, B; Kruse, J; Herman, M; Stoker, J

    2014-06-15

    Purpose: To design, fabricate and test a 3D-printed filter for proton range spreading in scanned proton beams. The narrow Bragg peak in lower-energy synchrotron-based scanned proton beams can result in longer treatment times for shallow targets due to energy switching time and plan quality degradation due to minimum monitor unit limitations. A filter with variable thicknesses patterned on the same scale as the beam's lateral spot size will widen the Bragg peak. Methods: The filter consists of pyramids dimensioned to have a Gaussian distribution in thickness. The pyramids are 2.5mm wide at the base, 0.6 mm wide at the peak, 5mm tall, and are repeated in a 2.5mm pseudo-hexagonal lattice. Monte Carlo simulations of the filter in a proton beam were run using TOPAS to assess the change in depth profiles and lateral beam profiles. The prototypes were constrained to a 2.5cm diameter disk to allow for micro-CT imaging of promising prototypes. Three different 3D printers were tested. Depth-doses with and without the prototype filter were then measured in a ~70MeV proton beam using a multilayer ion chamber. Results: The simulation results were consistent with design expectations. Prototypes printed on one printer were clearly unacceptable on visual inspection. Prototypes on a second printer looked acceptable, but the micro-CT image showed unacceptable voids within the pyramids. Prototypes from the third printer appeared acceptable visually and on micro-CT imaging. Depth dose scans using the prototype from the third printer were consistent with simulation results. Bragg peak width increased by about 3x. Conclusions: A prototype 3D printer pyramid filter for range spreading was successfully designed, fabricated and tested. The filter has greater design flexibility and lower prototyping and production costs compared to traditional ridge filters. Printer and material selection played a large role in the successful development of the filter.

  17. Effects of microstructure on the fatigue crack propagation resistance in composite microstructure by 3D fabric modeling for energy transport

    SciTech Connect

    Ishihara, T.; Kim, J.K.; Kobayashi, Y.

    1995-10-01

    In this study, martensite-ferrite dual phase steel composed of martensite in hard phase and ferrite in soft phase is made 3 dimensions fabric composite for energy transport and the difference in fatigue crack propagation behavior resulting from the structural size is investigated by fracture mechanics and microstructural method. The main results obtained are as follows: (1) the fatigue crack propagation rate is influenced by the ferrite grain size, in other words, in the low {Delta}K region the fatigue crack propagation rate is decreased with decreasing of the grain size but the difference of propagation rate resulted from the structural size is decreased as {Delta}K is increased; (2) the above results are explained by the degree of crack arrest effect of the martensite phase for the fatigue crack propagation depending on the ratio of reversed plastic zone size to the ferrite grain size.

  18. Fabrication of Compositionally and Topographically Complex Robust Tissue Forms by 3D-Electrochemical Compaction of Collagen

    PubMed Central

    Younesi, Mousa; Islam, Anowarul; Kishore, Vipuil; Panit, Stefi; Akkus, Ozan

    2015-01-01

    Collagen solutions are phase-transformed to mechanically robust shell structures with curviplanar topographies using electrochemically induced pH gradients. The process enables rapid layer-by-layer deposition of collagen-rich mixtures over the entire field simultaneously to obtain compositionally diverse multilayered structures. In-plane tensile strength and modulus of the electrocompacted collagen sheet samples were 5200 -fold and 2300 -fold greater than that of uncompacted collagen samples. Out of plane compression tests showed 27 -fold and fold increase in compressive stress and 46 -fold increase in compressive modulus compared to uncompacted collagen sheets. Cells proliferated 4.9 times faster, and cellular area spread was 2.7 times greater on compacted collagen sheets. Electrocompaction also resulted in 2.9 times greater focal adhesion area than on regular collagen hydrogel. The reported improvements in the cell-matrix interactions with electrocompaction would serve to expedite the population of electrocompacted collagen scaffolds by cells. The capacity of the method to fabricate nonlinear curved topographies with compositional heterogeneous layers is demonstrated by sequential deposition of collagenhydroxyapatite layer over a collagen layer. The complex curved topography of the nasal structure is replicated by the electrochemical compaction method. The presented electrochemical compaction process is an enabling modality which holds significant promise for reconstruction of a wide spectrum of topographically complex systems such as joint surfaces, craniofacial defects, ears, nose or urogenital forms. PMID:26069162

  19. Fabrication and detection of tissue engineered bone aggregates based on encapsulated human ADSCs within hybrid calcium alginate/bone powder gel-beads in a spinner flask.

    PubMed

    Song, Kedong; Yang, Yanfei; Xu, Lili; Tian, Jiaxin; Fan, Jiangli; Jiao, Zeren; Feng, Shihao; Wang, Hong; Wang, Yiwei; Wang, Ling; Liu, Tianqing

    2016-05-01

    Traditional treatment for bone diseases limits their clinical application due to undesirable host immune rejection, limited donator sources and severe pain and suffering for patients. Bone tissue engineering therefore is expected to be a more effective way in treating bone diseases. In the present study, hybrid calcium alginate/bone powder gel-beads with a uniform size distribution, good biocompatibility and osteoinductive capability, were prepared to be used as an in-vitro niche-like matrix. The beads were optimized using 2.5% (w/v) sodium alginate solution, 4.5% (w/v) CaCl2 solution and 5.0mg/mL bone powder using an easy-to-use method. Human ADSCs were cultured and induced into chondrocytes and osteoblasts, respectively. The cells were characterized by histological staining showing the ADSCs were able to maintain their characteristic morphology with multipotent differentiation ability. ADSCs at density of 5 × 10(6)cells/mL were encapsulated into the gel-beads aiming to explore cell expansion under different conditions and the osteogenic induction of ADSCs was verified by specific staining. Results demonstrated that the encapsulated ADSCs expanded 5.6 folds in 10 days under dynamic condition via spinner flask, and were able to differentiate into osteoblasts (OBs) with extensive mineralized nodules forming the bone aggregates over 3 weeks postosteogenic induction. In summary, hybrid gel-beads encapsulating ADSCs are proved to be feasible as a new method to fabricate tissue engineered bone aggregation with potential to treat skeletal injury in the near future. PMID:26952485

  20. A microfluidic opto-caloric switch for sorting of particles by using 3D-hydrodynamic focusing based on SLE fabrication capabilities.

    PubMed

    Meineke, G; Hermans, M; Klos, J; Lenenbach, A; Noll, R

    2016-03-01

    In a miniaturised flow switch fluid flows are controlled by reducing the local viscosity via absorption of laser radiation. Through this, the local flow rates are increased to switch the outlet port of a fluid flow carrying the analyte. The microfluidic chip is fabricated using Selective Laser-Induced Etching (SLE). SLE allows novel 3D-hydrodynamic focusing, realising circular shaped channel cross-sections and adapting interaction volume geometries to the profile of the laser radiation for optimised absorption. The performance of the switch is validated experimentally with a dyed analyte and video image processing. The ability to sort particles like cells is demonstrated at 8 Hz using polystyrene beads having a diameter of 8 μm. PMID:26862603

  1. Graphene-Protected 3D Sb-based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage.

    PubMed

    Ding, Yuan-Li; Wu, Chao; Kopold, Peter; van Aken, Peter A; Maier, Joachim; Yu, Yan

    2015-12-01

    Alloy anodes have shown great potential for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene-protected 3D Sb-based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic-assembling and subsequent confinement replacement strategy. As binder-free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g(-1) at 100 mA g(-1) and 295 mAh g(-1) at 1000 mA g(-1), and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g(-1). As for sodium storage properties, the reversible capacities of 517 mAh g(-1) at 50 mA g(-1) and 315 mAh g(-1) at 1000 mA g(-1), the capacity retention of 305 mAh g(-1) after 100 cycles at 300 mA g(-1) are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high-stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder-free anodes for LIBs and SIBs. PMID:26456169

  2. FABRICATION AND IN VITRO EVALUATION OF 5-FLOROURACIL LOADED CHONDROITIN SULFATE-SODIUM ALGINATE MICROSPHERES FOR COLON SPECIFIC DELIVERY.

    PubMed

    Raza, Hina; Ranjha, Nazar Muhammad; Razzaq, Rabia; Ansari, Mehvish; Mahmood, Asif; Rashid, Zermina

    2016-01-01

    Chondroitin sulfate and sodium alginate were incorporated in different ratios to prepare glutaraldehyde (GA) crosslinked microspheres by water-in-oil emulsion crosslinking method for delivery of 5-flurouracil (5-FU) to colon. Chemical interaction, surface morphology, thermal degradability, crystallinity evaluation, elemental analysis and drug release results were computed by using FTIR, SEM, DSC and TGA, PXRD, EXD and dissolution studies at pH 1.2, pH 6.8 and pH 7.4, respectively. Results revealed an acetal ring formation, non-porous surfaces, stability up to 450 degrees C with mass loss of 84.31%, variation in carbon and oxygen contents and targeted release at pH 7.4. Different kinetic models were applied on release studies i.e., zero order, first order, Higuchi and Korsmeyer-Peppas. Higuchi model was declared as best fit model based on r2 value (0.99) and mechanism of release was non-Fickian diffusion. A potential approach for colonic delivery of 5-FU was successfully developed. PMID:27180443

  3. Fabrication of a novel bone ash-reinforced gelatin/alginate/hyaluronic acid composite film for controlled drug delivery.

    PubMed

    Alemdar, Neslihan

    2016-10-20

    In this study, a novel pH-sensitive composite film with enhanced thermal and mechanical properties was prepared by the incorporation of bone ash at varying concentrations from 0 to 10v.% into gelatin/sodium alginate/hyaluronic acid (Gel/SA/HyA) polymeric structure for colon-specific drug delivery system. Films were characterized by FT-IR, SEM, and XRD analyses. Thermal and mechanical performances of films were determined by DSC, TGA and universal mechanical tester, respectively. Results proved that thermal stability and mechanical properties of bone ash-reinforced composite films improved significantly with respect to that of neat Gel/SA/HyA film. Cytotoxicity assay for composite films was carried out by using L929 cells. Water uptake capacity of films was determined by swelling test. Herein, release experiments of 5-Fluorouracil (5-FU) were performed in two different solutions (pH 2.1 and 7.4). The results assured that Gel/SA/HyA film containing BA could be considered as a potential biomaterial for controlled drug delivery systems. PMID:27474650

  4. 3D microscope

    NASA Astrophysics Data System (ADS)

    Iizuka, Keigo

    2008-02-01

    In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

  5. Fabrication of novel oxygen-releasing alginate beads as an efficient oxygen carrier for the enhancement of aerobic bioremediation of 1,4-dioxane contaminated groundwater.

    PubMed

    Lee, Chung-Seop; Le Thanh, Thao; Kim, Eun-Ju; Gong, Jianyu; Chang, Yoon-Young; Chang, Yoon-Seok

    2014-11-01

    Oxygen-releasing alginate beads (ORABs), a new concept of oxygen-releasing compounds (ORCs) designed to overcome some limitations regarding the fast oxygen release rate and the high pH equilibrium of ORCs, were fabricated to promote the stimulation of aerobic biodegradation in anaerobic groundwater. Slow oxygen-releasing rate and maintenance of constant pH were achieved by changing the parameters (ionic radius and valence) related to the cross-linking ions composing ORABs, and the best results were obtained for ORABs cross-linked with Al (Al-ORABs). Furthermore, the mechanism of the improved aerobic biodegradation using Al-ORABs under oxygen-limiting groundwater conditions was elucidated in batch and column studies with 1,4-dioxane and Mycrobacterium sp. PH-06 as a model contaminant and aerobic microbes, respectively. Maximum 1,4-dioxane degradations of 99% and 68.1% were achieved when Al-ORABs were applied in batch and column conditions, respectively, whereas 34.3% and 18% of 1,4-dioxane were degraded without Al-ORABs in batch and column conditions, respectively. PMID:25189509

  6. Fast and safe fabrication of a free-standing chitosan/alginate nanomembrane to promote stem cell delivery and wound healing

    PubMed Central

    Kong, Yi; Xu, Rui; Darabi, Mohammad Ali; Zhong, Wen; Luo, Gaoxing; Xing, Malcolm MQ; Wu, Jun

    2016-01-01

    Polymeric ultrathin membranes that are compatible with cells offer tremendous advantages for tissue engineering. In this article, we report a free-standing nanomembrane that was developed using a layer-by-layer self-assembly technique with a safe and sacrificial substrate method. After ionization, two oppositely charged polyelectrolytes, alginate and chitosan, were alternately deposited on a substrate of a solidified gelatin block to form an ultrathin nanomembrane. The space between the two adjacent layers was ∼200 nm. The thickness of the nanomembrane was proportional to the number of layers. The temperature-sensitive gelatin gel served as a sacrificial template at 37°C. The free-standing nanomembrane promoted bone marrow stem cell adhesion and proliferation. Fluorescence-activated cell sorting was used to analyze green-fluorescent-protein-positive mesenchymal stem cells from the wounds, which showed a significantly high survival and proliferation from the nanomembrane when cells were transplanted to mouse dorsal skin that had a full-thickness burn. The bone-marrow-stem-cell-loaded nanomembrane also accelerated wound contraction and epidermalization. Therefore, this methodology provides a fast and facile approach to construct free-standing ultrathin scaffolds for tissue engineering. The biocompatibility and free-standing nature of the fabricated nanomembrane may be particularly useful for stem cell delivery and wound healing. PMID:27354789

  7. Cancer stem cell marker-expressing cell-rich spheroid fabrication from PANC-1 cells using alginate microcapsules with spherical cavities templated by gelatin microparticles.

    PubMed

    Sakai, Shinji; Inamoto, Kazuya; Ashida, Tomoaki; Takamura, Ryo; Taya, Masahito

    2015-01-01

    Cancer stem-like cells (CSCs) are rare subpopulations of cancer cells. The development of three-dimensional tissues abundant in CSCs is important to both the understanding and establishment of novel therapeutics targeting them. Here, we describe the fabrication of multicellular tumor spheroids (MTSs) abundant in CSCs by employing alginate microcapsules with spherical cavities templated by cell-enclosing gelatin microparticles. Encapsulated human pancreatic cancer cell line PANC-1 cells grew for 14 days until they filled the cavities. The percentage of cells expressing reported CSC markers CD24, CD44, and epithelial-specific antigen (ESA), increased during this growth period. The percentage at 24 days of incubation, 22%, was 1.6 times higher than that of MTSs formed on a nonadherent surface in the same period of incubation. The MTSs in microcapsules could be cryopreserved in liquid nitrogen using a conventional method. No significant difference in the content of CSC marker-expressing cells was detected at 3 days of incubation when thawed after cryopreservation for 2 weeks, compared with cells incubated without prior cryopreservation. PMID:26013961

  8. Fast and safe fabrication of a free-standing chitosan/alginate nanomembrane to promote stem cell delivery and wound healing.

    PubMed

    Kong, Yi; Xu, Rui; Darabi, Mohammad Ali; Zhong, Wen; Luo, Gaoxing; Xing, Malcolm Mq; Wu, Jun

    2016-01-01

    Polymeric ultrathin membranes that are compatible with cells offer tremendous advantages for tissue engineering. In this article, we report a free-standing nanomembrane that was developed using a layer-by-layer self-assembly technique with a safe and sacrificial substrate method. After ionization, two oppositely charged polyelectrolytes, alginate and chitosan, were alternately deposited on a substrate of a solidified gelatin block to form an ultrathin nanomembrane. The space between the two adjacent layers was ∼200 nm. The thickness of the nanomembrane was proportional to the number of layers. The temperature-sensitive gelatin gel served as a sacrificial template at 37°C. The free-standing nanomembrane promoted bone marrow stem cell adhesion and proliferation. Fluorescence-activated cell sorting was used to analyze green-fluorescent-protein-positive mesenchymal stem cells from the wounds, which showed a significantly high survival and proliferation from the nanomembrane when cells were transplanted to mouse dorsal skin that had a full-thickness burn. The bone-marrow-stem-cell-loaded nanomembrane also accelerated wound contraction and epidermalization. Therefore, this methodology provides a fast and facile approach to construct free-standing ultrathin scaffolds for tissue engineering. The biocompatibility and free-standing nature of the fabricated nanomembrane may be particularly useful for stem cell delivery and wound healing. PMID:27354789

  9. Self-Assembled 3D Ordered Macroporous Structures for Tissue Engineering Scaffolds

    NASA Astrophysics Data System (ADS)

    Juan, Wen-Tau; Chung, Kuo-Yuan; Mishra, Narayan; Lin, Keng-Hui

    2008-03-01

    A simple, inexpensive and fast microfluidic method to fabricate three-dimensional ordered macroporous gel is demonstrated using alginate as the scaffold material. The microfluidic device consists of two concentric micropipettes where one is nested inside the other. Nitrogen gas and aqueous alginate solution with Pluronic F127 are pumped through the inner and the outer channel respectively. Under appropriate conditions, bubbles of a uniform size are generated within the device at few thousand Hz. We show the control over bubble size by the gas pressure and quantitatively predict the size dependence from the geometry of fluidic device. Monodisperse bubbles are collected and self-assemble into crystal structures as wet foam. The alginate solution between bubbles is crosslinked by divalent calcium ions and turns into 3D ordered macroporous gel where the pores are highly interconnected. The pore size can be directly controlled by the bubble size which ranges from few tens microns to few millimeters. This technique promises a versatile and robust way to make 3D ordered tissue engineering scaffolds.

  10. Fabrication and evaluation of electrohydrodynamic jet 3D printed polycaprolactone/chitosan cell carriers using human embryonic stem cell-derived fibroblasts.

    PubMed

    Wu, Yang; Sriram, Gopu; Fawzy, Amr S; Fuh, Jerry Yh; Rosa, Vinicius; Cao, Tong; Wong, Yoke San

    2016-08-01

    Biological function of adherent cells depends on the cell-cell and cell-matrix interactions in three-dimensional space. To understand the behavior of cells in 3D environment and their interactions with neighboring cells and matrix requires 3D culture systems. Here, we present a novel 3D cell carrier scaffold that provides an environment for routine 3D cell growth in vitro We have developed thin, mechanically stable electrohydrodynamic jet (E-jet) 3D printed polycaprolactone and polycaprolactone/Chitosan macroporous scaffolds with precise fiber orientation for basic 3D cell culture application. We have evaluated the application of this technology by growing human embryonic stem cell-derived fibroblasts within these 3D scaffolds. Assessment of cell viability and proliferation of cells seeded on polycaprolactone and polycaprolactone/Chitosan 3D-scaffolds show that the human embryonic stem cell-derived fibroblasts could adhere and proliferate on the scaffolds over time. Further, using confocal microscopy we demonstrate the ability to use fluorescence-labelled cells that could be microscopically monitored in real-time. Hence, these 3D printed polycaprolactone and polycaprolactone/Chitosan scaffolds could be used as a cell carrier for in vitro 3D cell culture-, bioreactor- and tissue engineering-related applications in the future. PMID:27252227

  11. 3D Printing of Graphene Aerogels.

    PubMed

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction. PMID:26861680

  12. Microcapsules and 3D customizable shelled microenvironments from laser direct-written microbeads.

    PubMed

    Kingsley, David M; Dias, Andrew D; Corr, David T

    2016-10-01

    Microcapsules are shelled 3D microenvironments, with a liquid core. These core-shelled structures enable cell-cell contact, cellular proliferation and aggregation within the capsule, and can be utilized for controlled release of encapsulated contents. Traditional microcapsule fabrication methods provide limited control of capsule size, and are unable to control capsule placement. To overcome these limitations, we demonstrate size and spatial control of poly-l-lysine and chitosan microcapsules, using laser direct-write (LDW) printing, and subsequent processing, of alginate microbeads. Additionally, microbeads were used as volume pixels (voxels) to form continuous 3D hydrogel structures, which were processed like capsules, to form custom shelled aqueous-core 3D structures of prescribed geometry; such as strands, rings, and bifurcations. Heterogeneous structures were also created with controlled initial locations of different cell types, to demonstrate the ability to prescribe cell signaling (heterotypic and homotypic) in co-culture conditions. Herein, we demonstrate LDW's ability to fabricate intricate 3D structures, essentially with "printed macroporosity," and to precisely control structural composition by bottom-up fabrication in a bead-by-bead manner. The structural and compositional control afforded by this process enables the creation of a wide range of new constructs, with many potential applications in tissue engineering and regenerative medicine. Biotechnol. Bioeng. 2016;113: 2264-2274. © 2016 Wiley Periodicals, Inc. PMID:27070458

  13. Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.

    PubMed

    Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa

    2016-03-15

    Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor. PMID:26386332

  14. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435

  15. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles.

    PubMed

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-12-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %. PMID:26745977

  16. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles

    NASA Astrophysics Data System (ADS)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-01-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %.

  17. Development of paper-based microfluidic analytical device for iron assay using photomask printed with 3D printer for fabrication of hydrophilic and hydrophobic zones on paper by photolithography.

    PubMed

    Asano, Hitoshi; Shiraishi, Yukihide

    2015-07-01

    This paper describes a paper-based microfluidic analytical device for iron assay using a photomask printed with a 3D printer for fabrication of hydrophilic and hydrophobic zones on the paper by photolithography. Several designed photomasks for patterning paper-based microfluidic analytical devices can be printed with a 3D printer easily, rapidly and inexpensively. A chromatography paper was impregnated with the octadecyltrichlorosilane n-hexane solution and hydrophobized. After the hydrophobic zone of the paper was exposed to the UV light through the photomask, the hydrophilic zone was generated. The smallest functional hydrophilic channel and hydrophobic barrier were ca. 500 μm and ca. 100 μm in width, respectively. The fabrication method has high stability, resolution and precision for hydrophilic channel and hydrophobic barrier. This test paper was applied to the analysis of iron in water samples using a colorimetry with phenanthroline. PMID:26088776

  18. Fabrication and assessment of 3D printed anatomical models of the lower limb for anatomical teaching and femoral vessel access training in medicine.

    PubMed

    O'Reilly, Michael K; Reese, Sven; Herlihy, Therese; Geoghegan, Tony; Cantwell, Colin P; Feeney, Robin N M; Jones, James F X

    2016-01-01

    For centuries, cadaveric dissection has been the touchstone of anatomy education. It offers a medical student intimate access to his or her first patient. In contrast to idealized artisan anatomical models, it presents the natural variation of anatomy in fine detail. However, a new teaching construct has appeared recently in which artificial cadavers are manufactured through three-dimensional (3D) printing of patient specific radiological data sets. In this article, a simple powder based printer is made more versatile to manufacture hard bones, silicone muscles and perfusable blood vessels. The approach involves blending modern approaches (3D printing) with more ancient ones (casting and lost-wax techniques). These anatomically accurate models can augment the approach to anatomy teaching from dissection to synthesis of 3D-printed parts held together with embedded rare earth magnets. Vascular simulation is possible through application of pumps and artificial blood. The resulting arteries and veins can be cannulated and imaged with Doppler ultrasound. In some respects, 3D-printed anatomy is superior to older teaching methods because the parts are cheap, scalable, they can cover the entire age span, they can be both dissected and reassembled and the data files can be printed anywhere in the world and mass produced. Anatomical diversity can be collated as a digital repository and reprinted rather than waiting for the rare variant to appear in the dissection room. It is predicted that 3D printing will revolutionize anatomy when poly-material printing is perfected in the early 21st century. PMID:26109268

  19. Construction of Modular Hydrogel Sheets for Micropatterned Macro-scaled 3D Cellular Architecture.

    PubMed

    Son, Jaejung; Bae, Chae Yun; Park, Je-Kyun

    2016-01-01

    Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue geometry. The resulting 3D hydrogel-based cellular constructs have been introduced as an alternative to animal experiments for advanced biological studies, pharmacological assays and organ transplant applications. Although hydrogel-based particles and fibers can be easily fabricated, it is difficult to manipulate them for tissue reconstruction. In this video, we describe a fabrication method for micropatterned alginate hydrogel sheets, together with their assembly to form a macro-scale 3D cell culture system with a controlled cellular microenvironment. Using a mist form of the calcium gelling agent, thin hydrogel sheets are easily generated with a thickness in the range of 100 - 200 µm, and with precise micropatterns. Cells can then be cultured with the geometric guidance of the hydrogel sheets in freestanding conditions. Furthermore, the hydrogel sheets can be readily manipulated using a micropipette with an end-cut tip, and can be assembled into multi-layered structures by stacking them using a patterned polydimethylsiloxane (PDMS) frame. These modular hydrogel sheets, which can be fabricated using a facile process, have potential applications of in vitro drug assays and biological studies, including functional studies of micro- and macrostructure and tissue reconstruction. PMID:26779839

  20. Digital microfluidic three-dimensional cell culture and chemical screening platform using alginate hydrogels

    PubMed Central

    2015-01-01

    Electro wetting-on-dielectric (EWOD) digital microfluidics (DMF) can be used to develop improved chemical screening platforms using 3-dimensional (3D) cell culture. Alginate hydrogels are one common method by which a 3D cell culture environment is created. This paper presents a study of alginate gelation on EWOD DMF and investigates designs to obtain uniform alginate hydrogels that can be repeatedly addressed by any desired liquids. A design which allows for gels to be retained in place during liquid delivery and removal without using any physical barriers or hydrophilic patterning of substrates is presented. A proof of concept screening platform is demonstrated by examining the effects of different concentrations of a test chemical on 3D cells in alginate hydrogels. In addition, the temporal effects of the various chemical concentrations on different hydrogel posts are demonstrated, thereby establishing the benefits of an EWOD DMF 3D cell culture and chemical screening platform using alginate hydrogels. PMID:25945142

  1. Digital microfluidic three-dimensional cell culture and chemical screening platform using alginate hydrogels.

    PubMed

    George, Subin M; Moon, Hyejin

    2015-03-01

    Electro wetting-on-dielectric (EWOD) digital microfluidics (DMF) can be used to develop improved chemical screening platforms using 3-dimensional (3D) cell culture. Alginate hydrogels are one common method by which a 3D cell culture environment is created. This paper presents a study of alginate gelation on EWOD DMF and investigates designs to obtain uniform alginate hydrogels that can be repeatedly addressed by any desired liquids. A design which allows for gels to be retained in place during liquid delivery and removal without using any physical barriers or hydrophilic patterning of substrates is presented. A proof of concept screening platform is demonstrated by examining the effects of different concentrations of a test chemical on 3D cells in alginate hydrogels. In addition, the temporal effects of the various chemical concentrations on different hydrogel posts are demonstrated, thereby establishing the benefits of an EWOD DMF 3D cell culture and chemical screening platform using alginate hydrogels. PMID:25945142

  2. Bioprinting of 3D hydrogels.

    PubMed

    Stanton, M M; Samitier, J; Sánchez, S

    2015-08-01

    Three-dimensional (3D) bioprinting has recently emerged as an extension of 3D material printing, by using biocompatible or cellular components to build structures in an additive, layer-by-layer methodology for encapsulation and culture of cells. These 3D systems allow for cell culture in a suspension for formation of highly organized tissue or controlled spatial orientation of cell environments. The in vitro 3D cellular environments simulate the complexity of an in vivo environment and natural extracellular matrices (ECM). This paper will focus on bioprinting utilizing hydrogels as 3D scaffolds. Hydrogels are advantageous for cell culture as they are highly permeable to cell culture media, nutrients, and waste products generated during metabolic cell processes. They have the ability to be fabricated in customized shapes with various material properties with dimensions at the micron scale. 3D hydrogels are a reliable method for biocompatible 3D printing and have applications in tissue engineering, drug screening, and organ on a chip models. PMID:26066320

  3. A New Total Digital Smile Planning Technique (3D-DSP) to Fabricate CAD-CAM Mockups for Esthetic Crowns and Veneers

    PubMed Central

    Mastrangelo, F.; Gherlone, E. F.; Gastaldi, G.

    2016-01-01

    Purpose. Recently, the request of patients is changed in terms of not only esthetic but also previsualization therapy planning. The aim of this study is to evaluate a new 3D-CAD-CAM digital planning technique that uses a total digital smile process. Materials and Methods. Study participants included 28 adult dental patients, aged 19 to 53 years, with no oral, periodontal, or systemic diseases. For each patient, 3 intra- and extraoral pictures and intraoral digital impressions were taken. The digital images improved from the 2D Digital Smile System software and the scanner stereolithographic (STL) file was matched into the 3D-Digital Smile System to obtain a virtual previsualization of teeth and smile design. Then, the mockups were milled using a CAM system. Minimally invasive preparation was carried out on the enamel surface with the mockups as position guides. Results. The patients found both the digital smile design previsualization (64.3%) and the milling mockup test (85.7%) very effective. Conclusions. The new total 3D digital planning technique is a predictably and minimally invasive technique, allows easy diagnosis, and improves the communication with the patient and helps to reduce the working time and the errors usually associated with the classical prosthodontic manual step. PMID:27478442

  4. A New Total Digital Smile Planning Technique (3D-DSP) to Fabricate CAD-CAM Mockups for Esthetic Crowns and Veneers.

    PubMed

    Cattoni, F; Mastrangelo, F; Gherlone, E F; Gastaldi, G

    2016-01-01

    Purpose. Recently, the request of patients is changed in terms of not only esthetic but also previsualization therapy planning. The aim of this study is to evaluate a new 3D-CAD-CAM digital planning technique that uses a total digital smile process. Materials and Methods. Study participants included 28 adult dental patients, aged 19 to 53 years, with no oral, periodontal, or systemic diseases. For each patient, 3 intra- and extraoral pictures and intraoral digital impressions were taken. The digital images improved from the 2D Digital Smile System software and the scanner stereolithographic (STL) file was matched into the 3D-Digital Smile System to obtain a virtual previsualization of teeth and smile design. Then, the mockups were milled using a CAM system. Minimally invasive preparation was carried out on the enamel surface with the mockups as position guides. Results. The patients found both the digital smile design previsualization (64.3%) and the milling mockup test (85.7%) very effective. Conclusions. The new total 3D digital planning technique is a predictably and minimally invasive technique, allows easy diagnosis, and improves the communication with the patient and helps to reduce the working time and the errors usually associated with the classical prosthodontic manual step. PMID:27478442

  5. Optoplasmonics: hybridization in 3D

    NASA Astrophysics Data System (ADS)

    Rosa, L.; Gervinskas, G.; Žukauskas, A.; Malinauskas, M.; Brasselet, E.; Juodkazis, S.

    2013-12-01

    Femtosecond laser fabrication has been used to make hybrid refractive and di ractive micro-optical elements in photo-polymer SZ2080. For applications in micro- uidics, axicon lenses were fabricated (both single and arrays), for generation of light intensity patterns extending through the entire depth of a typically tens-of-micrometers deep channel. Further hybridisation of an axicon with a plasmonic slot is fabricated and demonstrated nu- merically. Spiralling chiral grooves were inscribed into a 100-nm-thick gold coating sputtered over polymerized micro-axicon lenses, using a focused ion beam. This demonstrates possibility of hybridisation between optical and plasmonic 3D micro-optical elements. Numerical modelling of optical performance by 3D-FDTD method is presented.

  6. A New Approach for Fabricating Collagen/ECM-Based Bioinks Using Preosteoblasts and Human Adipose Stem Cells.

    PubMed

    Lee, Hyeong Jin; Kim, Yong Bok; Ahn, Seung Hyun; Lee, Ji-Seon; Jang, Chul Ho; Yoon, Hyeon; Chun, Wook; Kim, Geun Hyung

    2015-06-24

    Cell-printing methods have been used widely in tissue regeneration because they enable fabricating biomimetic 3D structures laden with various cells. To achieve a cell-matrix block, various natural hydrogels that are nontoxic, biocompatible, and printable have been combined to obtain "bioinks." Unfortunately, most bioinks, including those with alginates, show low cell-activating properties. Here, a strategy for obtaining highly bioactive ink, which consisted of collagen/extracellular matrix (ECM) and alginate, for printing 3D porous cell blocks is developed. An in vitro assessment of the 3D porous structures laden with preosteoblasts and human adipose stem cells (hASCs) demonstrates that the cells in the bioinks are viable. Osteogenic activities with the designed bioinks show much higher levels than with the "conventional" alginate-based bioink. Furthermore, the hepatogenic differentiation ability of hASCs with the bioink is evaluated using the liver-specific genes, albumin, and TDO2, under hepatogenic differentiation conditions. The genes are activated within the 3D cell block fabricated using the new bioink. These results demonstrate that the 3D cell-laden structure fabricated using collagen/ECM-based bioinks can provide a novel platform for various tissue engineering applications. PMID:25874573

  7. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  8. Fabrication of 3D interconnected porous TiO2 nanotubes templated by poly(vinyl chloride-g-4-vinyl pyridine) for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Koh, Joo Hwan; Koh, Jong Kwan; Seo, Jin Ah; Shin, Jong-Shik; Kim, Jong Hak

    2011-09-01

    Porous TiO2 nanotube arrays with three-dimensional (3D) interconnectivity were prepared using a sol-gel process assisted by poly(vinyl chloride-graft-4-vinyl pyridine), PVC-g-P4VP graft copolymer and a ZnO nanorod template. A 7 µm long ZnO nanorod array was grown from the fluorine-doped tin oxide (FTO) glass via a liquid phase deposition method. The TiO2 sol-gel solution templated by the PVC-g-P4VP graft copolymer produced a random 3D interconnection between the adjacent ZnO nanorods during spin coating. Upon etching of ZnO, TiO2 nanotubes consisting of 10-15 nm nanoparticles were generated, as confirmed by wide-angle x-ray scattering (WAXS), energy-filtering transmission electron microscopy (EF-TEM) and field-emission scanning electron microscopy (FE-SEM). The ordered and interconnected nanotube architecture showed an enhanced light scattering effect and increased penetration of polymer electrolytes in dye-sensitized solar cells (DSSC). The energy conversion efficiency reached 1.82% for liquid electrolyte, and 1.46% for low molecular weight (Mw) and 0.74% for high Mw polymer electrolytes.

  9. A novel method of hotspot temperature reduction for a 3D stacked CMOS IC chip device fabricated on an ultrathin substrate

    NASA Astrophysics Data System (ADS)

    Kato, Fumiki; Nakagawa, Hiroshi; Aoyagi, Masahiro

    2013-02-01

    A high-performance thermal management method for three-dimensional integrated circuit (IC) integration has been developed for use in conjunction with a three-dimensional (3D) large-scale integration (LSI) technology. By depositing a 10 µm thick high thermal conductivity (HTC) film consisting of 1680 alternating layers of silicon and graphite nano-films directly onto the backside of a Si substrate via an automatic sequencing sputtering method, reduction in the transient hotspot temperature in a thin-substrate CMOS IC chip is achieved. It is shown that this novel HTC film is able to overcome the thermal problems associated with thin substrates and allow the cooling of stacked ICs. In the work described in this paper, we demonstrated the performance of the HTC using a 100 µm thick substrate IC chip consisting of a complementary metal-oxide semiconductor (CMOS) ring oscillator circuit film. Our experimental results, which were confirmed in simulation, reveal a 28% reduction in the hotspot temperature rise owing to the presence of the HTC film. This technology is applicable to future developments in the 3D ultrathin substrate LSI chip stacking technology utilizing through-silicon vias (TSVs) and micro-bumps.

  10. Microfluidic generation of hollow Ca-alginate microfibers.

    PubMed

    Meng, Zhi-Jun; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

    2016-07-01

    This work reports on an efficient microfluidic approach for continuous production of hollow Ca-alginate microfibers with controllable structures and functions. A coaxial microcapillary microfluidic device combined with a rotator is constructed to produce a cylindrical flow jet with four aqueous solutions as templates for continuous fabrication and collection of microfibers. A four-aqueous-phase flow jet with an intermediate buffer flow between the Ca(2+)-containing and alginate-containing flows is used as the template for microfiber fabrication. The buffer flow efficiently controls the diffusion of Ca(2+) into the alginate-containing flow as well as the crosslinking reaction, thus ensuring the continuous fabrication of hollow Ca-alginate microfibers under relatively low flow rates without clogging of the microchannel. The structure of the hollow microfibers can be flexibly adjusted by changing the flow rates and device dimensions. Meanwhile, the continuous fabrication process of the microfibers allows flexible incorporation of a functional component into the sheath flow for functionalization and addition of active substances in the core flow for encapsulation. This is demonstrated by fabricating hollow Ca-alginate microfibers with a wall containing magnetic nanoparticles for magnetic functionalization and with hollow internals containing Chlorella pyrenoidosa cells for confined growth. This work provides an efficient strategy for continuous fabrication of functional hollow Ca-alginate microfibers with controllable structures and functions. PMID:27302737

  11. Design, fabrication, and implementation of voxel-based 3D printed textured phantoms for task-based image quality assessment in CT

    NASA Astrophysics Data System (ADS)

    Solomon, Justin; Ba, Alexandre; Diao, Andrew; Lo, Joseph; Bier, Elianna; Bochud, François; Gehm, Michael; Samei, Ehsan

    2016-03-01

    In x-ray computed tomography (CT), task-based image quality studies are typically performed using uniform background phantoms with low-contrast signals. Such studies may have limited clinical relevancy for modern non-linear CT systems due to possible influence of background texture on image quality. The purpose of this study was to design and implement anatomically informed textured phantoms for task-based assessment of low-contrast detection. Liver volumes were segmented from 23 abdominal CT cases. The volumes were characterized in terms of texture features from gray-level co-occurrence and run-length matrices. Using a 3D clustered lumpy background (CLB) model, a fitting technique based on a genetic optimization algorithm was used to find the CLB parameters that were most reflective of the liver textures, accounting for CT system factors of spatial blurring and noise. With the modeled background texture as a guide, a cylinder phantom (165 mm in diameter and 30 mm height) was designed, containing 20 low-contrast spherical signals (6 mm in diameter at targeted contrast levels of ~3.2, 5.2, 7.2, 10, and 14 HU, 4 repeats per signal). The phantom was voxelized and input into a commercial multi-material 3D printer (Object Connex 350), with custom software for voxel-based printing. Using principles of digital half-toning and dithering, the 3D printer was programmed to distribute two base materials (VeroWhite and TangoPlus, nominal voxel size of 42x84x30 microns) to achieve the targeted spatial distribution of x-ray attenuation properties. The phantom was used for task-based image quality assessment of a clinically available iterative reconstruction algorithm (Sinogram Affirmed Iterative Reconstruction, SAFIRE) using a channelized Hotelling observer paradigm. Images of the textured phantom and a corresponding uniform phantom were acquired at six dose levels and observer model performance was estimated for each condition (5 contrasts x 6 doses x 2 reconstructions x 2

  12. Fabrication of a definitive obturator from a 3D cast with a chairside digital scanner for a patient with severe gag reflex: a clinical report.

    PubMed

    Londono, Jimmy; Abreu, Amara; Baker, Philip S; Furness, Alan R

    2015-11-01

    Patient gagging is a common problem during dental procedures such as maxillary impression making. This clinical report describes the use of a chairside intraoral scanner for a patient with a hypersensitive gag reflex. The technique proved to be a more comfortable alternative for the patient and an accurate method for the clinician to capture both hard and soft tissue detail for the fabrication of a definitive obturator. PMID:26182852

  13. 3D-Printed Microfluidics.

    PubMed

    Au, Anthony K; Huynh, Wilson; Horowitz, Lisa F; Folch, Albert

    2016-03-14

    The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite-element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia. PMID:26854878

  14. Fabrication and characterization of bio-engineered cardiac pseudo tissues

    PubMed Central

    Xu, Tao; Baicu, Catalin; Aho, Michael; Zile, Michael; Boland, Thomas

    2014-01-01

    We report to fabricate functional three-dimensional (3D) tissue constructs by using an inkjet based bio-prototyping method. With the use of the modified inkjet printers, contractile cardiac hybrids that exhibit the forms of the 3D rectangular sheet and even the “half heart” (with two connected ventricles) have been fabricated by arranging alternate layers of biocompatible alginate hydrogels and mammalian cardiac cells according to pre-designed 3D patterns. In this study, primary feline adult and H1 cardiomyocytes were used as model cardiac cells. Alginate hydrogels with controlled micro-shell structures were built by spraying cross-linkers in micro drops onto un-gelled alginic acid. The cells remained viable in constructs as thick as 1 cm due to the programmed porosity. Microscopic and macroscopic contractile functions of these cardiomyocytes constructs were observed in vitro. These results suggest that the inkjet bio-prototyping method could be used for hierarchical design of functional cardiac pseudo tissues, balanced with porosity for mass transport and structural support. PMID:20811105

  15. 3d-3d correspondence revisited

    NASA Astrophysics Data System (ADS)

    Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-01

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  16. 3D Printing for Tissue Engineering

    PubMed Central

    Jia, Jia; Yao, Hai; Mei, Ying

    2016-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728

  17. Characteristics of biochar derived from marine macroalgae and fabrication of granular biochar by entrapment in calcium-alginate beads for phosphate removal from aqueous solution.

    PubMed

    Jung, Kyung-Won; Jeong, Tae-Un; Kang, Ho-Jeong; Ahn, Kyu-Hong

    2016-07-01

    In this work, granular biochar, Laminaria japonica-derived biochar (LB)-calcium alginate beads (LB-CAB), was successfully prepared by dropping a mixture of powder biochar and alginate solution into a calcium chloride solution for phosphate adsorption. Among different marine macroalgae derived biochars, LB exhibited the best performance, showing a phosphate removal rate of 97.02%, which was attributed to its high Ca/P and Mg/P ratios. With increasing pyrolysis temperature up to 600°C, the physicochemical properties of LB became suitable for adsorbing phosphate. Experimental results of kinetics and equilibrium isotherms at different temperatures (10-30°C) showed that the phosphate adsorption process is endothermic and is mainly controlled by external mass transfer and the intraparticle diffusion rate. The maximum adsorption capacity was found to be 157.7mgg(-1) at 30°C, as fitted by the Langmuir-Freundlich model, which is higher than capacities of other powder form of biochars. PMID:27010340

  18. A 60-GHz-band 2 x 4 planar dipole array antenna module fabricated by 3-D SiP technology

    NASA Astrophysics Data System (ADS)

    Suematsu, Noriharu; Suzuki, Yuya; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    2014-08-01

    A 2 × 4 phased array antenna module has been developed for 60-GHz-band short- range high-speed wireless communication terminals. To realize the required vertical distance between the antenna elements, the module is made of five sheets of multi-layered organic substrates vertically stacked with Cu balls, and the 1 x 4 dipole array antenna is placed on both the top and bottom organic substrates. To reduce the mutual coupling between the element antennas, a monolithic microwave integrated circuit (MMIC) is flip-chip mounted on the feed line of each element antenna. The Au-stud bump flip-chip mounting technique helps achieve a lower return loss in the transition section at the MMIC than the Au-wire bonded. The placement accuracy of each antenna element in the vertical direction, 60-GHz signal vertical interconnection between the substrates with Cu balls, and flip-chip mounting of the MMIC are confirmed by 3-D computed tomography (CT) scans.

  19. Influence of the laser assisted fabricated 3D porous scaffolds from bioceramoplasts of micron and nano sizes on culture of MMSC

    NASA Astrophysics Data System (ADS)

    Shishkovsky, I.; Volchkov, S.

    2013-11-01

    The objective of the investigation was to test the biocompatibility of 3D porous biopolymer matrices (tissue-cellular scaffolds), made of biocompatible and bioresorbable polymers (polycarbonate, polyetheretherketone /PEEK/, polycaprolactone), including the materials with biocompatible oxide ceramics additive (TiO2, Al2O3, ZrO2 and hydroxyapatite) of micron and nano sizes, for tissue-engineering purposes. The porous samples were prepared via a layer-by-layer SLS method. The surface microstructures and their roughness were analyzed by the optical microscopy equipped with the cell analysis software. The cellular morphology, proliferative activity and adhesion of the polymeric and ceramopolymeric matrices were the subjects for comparison. The study showed that all the tested materials posessed biocompatible properties. The experimentally estimated cell duplication speed per day turned out to be maximal for polycarbonate (0.279 duplications per day) and for PEEK + Al2O3 = 3:1 group (0.30 dupl/day) against 0.387 dupl/day for the reference sample and 0.270 dupl/day for the group of cells placed close to the pure titanium samples.

  20. A Controlled Design of Aligned and Random Nanofibers for 3D Bi-functionalized Nerve Conduits Fabricated via a Novel Electrospinning Set-up.

    PubMed

    Kim, Jeong In; Hwang, Tae In; Aguilar, Ludwig Erik; Park, Chan Hee; Kim, Cheol Sang

    2016-01-01

    Scaffolds made of aligned nanofibers are favorable for nerve regeneration due to their superior nerve cell attachment and proliferation. However, it is challenging not only to produce a neat mat or a conduit form with aligned nanofibers but also to use these for surgical applications as a nerve guide conduit due to their insufficient mechanical strength. Furthermore, no studies have been reported on the fabrication of aligned nanofibers and randomly-oriented nanofibers on the same mat. In this study, we have successfully produced a mat with both aligned and randomly-oriented nanofibers by using a novel electrospinning set up. A new conduit with a highly-aligned electrospun mat is produced with this modified electrospinning method, and this proposed conduit with favorable features, such as selective permeability, hydrophilicity and nerve growth directional steering, were fabricated as nerve guide conduits (NGCs). The inner surface of the nerve conduit is covered with highly aligned electrospun nanofibers and is able to enhance the proliferation of neural cells. The central part of the tube is double-coated with randomly-oriented nanofibers over the aligned nanofibers, strengthening the weak mechanical strength of the aligned nanofibers. PMID:27021221

  1. A Controlled Design of Aligned and Random Nanofibers for 3D Bi-functionalized Nerve Conduits Fabricated via a Novel Electrospinning Set-up

    PubMed Central

    Kim, Jeong In; Hwang, Tae In; Aguilar, Ludwig Erik; Park, Chan Hee; Kim, Cheol Sang

    2016-01-01

    Scaffolds made of aligned nanofibers are favorable for nerve regeneration due to their superior nerve cell attachment and proliferation. However, it is challenging not only to produce a neat mat or a conduit form with aligned nanofibers but also to use these for surgical applications as a nerve guide conduit due to their insufficient mechanical strength. Furthermore, no studies have been reported on the fabrication of aligned nanofibers and randomly-oriented nanofibers on the same mat. In this study, we have successfully produced a mat with both aligned and randomly-oriented nanofibers by using a novel electrospinning set up. A new conduit with a highly-aligned electrospun mat is produced with this modified electrospinning method, and this proposed conduit with favorable features, such as selective permeability, hydrophilicity and nerve growth directional steering, were fabricated as nerve guide conduits (NGCs). The inner surface of the nerve conduit is covered with highly aligned electrospun nanofibers and is able to enhance the proliferation of neural cells. The central part of the tube is double-coated with randomly-oriented nanofibers over the aligned nanofibers, strengthening the weak mechanical strength of the aligned nanofibers. PMID:27021221

  2. SU-C-213-07: Fabrication and Testing of a 3D-Printed Small Animal Rectal Cooling Device to Evaluate Local Hypothermia as a Radioprotector During Prostate SBRT

    SciTech Connect

    Hrycushko, B; Chopra, R; Futch, C; Bing, C; Wodzak, M; Stojadinovic, S; Jiang, S; Medin, P

    2015-06-15

    Purpose: The protective effects of induced or even accidental hypothermia on the human body are widespread with several medical uses currently under active research. In vitro experiments using human cell lines have shown hypothermia provides a radioprotective effect that becomes more pronounced at large, single-fraction doses common to SBRT treatments. Relevant to prostate SBRT, this work details the fabrication and testing of a 3D-printed cooling device to facilitate the investigation of the radioprotective effect of local hypothermia on the rat rectum. Methods: A 3cm long, two-channel rectal cooling device was designed in SOLIDWORKS CAD for 3D printing. The water intake nozzle is connected to a 1mm diameter brass pipe from which water flows and circulates back around to the exit nozzle. Both nozzles are connected by plastic tubing to a water chiller pump. Following leak-proof testing, fiber optic temperature probes were used to evaluate the temperature over time when placed adjacent to the cooling device within a rat rectum. MRI thermometry characterized the relative temperature distribution in concentric ROIs surrounding the probe. CBCT images from a small-animal irradiator were evaluated for imaging artifacts which could affect Monte Carlo dose calculations during treatment planning. Results: The rectal temperature adjacent to the cooling device decreased from body temperature (37°C) to 15°C in 10–20 minutes from device insertion. Rectal temperature was maintained at 15±3°C during active cooling. MRI thermometry tests revealed a steep temperature gradient with increasing distance from the cooling device, with the desired temperature range maintained within the surrounding few millimeters. Conclusion: A 3D printed rectal cooling device was fabricated for the purpose of inducing local hypothermia in rat rectums. Rectal cooling capabilities were characterized in-vivo to facilitate an investigation of the radioprotective effect of hypothermia for late rectal

  3. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

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

    PubMed

    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. PMID:26782020

  5. Design and fabrication of a 3D-structured gold film with nanopores for local electric field enhancement in the pore

    NASA Astrophysics Data System (ADS)

    Grant-Jacob, James A.; Zin Oo, Swe; Carpignano, Francesca; Boden, Stuart A.; Brocklesby, William S.; Charlton, Martin D. B.; Melvin, Tracy

    2016-02-01

    Three-dimensionally structured gold membrane films with nanopores of defined, periodic geometries are designed and fabricated to provide the spatially localised enhancement of electric fields by manipulation of the plasmons inside nanopores. Square nanopores of different size and orientation relative to the pyramid are considered for films in aqueous and air environments, which allow for control of the position of electric fields within the structure. Designs suitable for use with 780 nm light were created. Here, periodic pyramidal cavities produced by potassium hydroxide etching to the {111} planes of (100) silicon substrates are used as templates for creating a periodic, pyramidal structured, free-standing thin gold film. Consistent with the findings from the theoretical studies, a nano-sized hole of 50 nm square was milled through the gold film at a specific location in the cavity to provide electric field control which can subsequently used for enhancement of fluorescence or Raman scattering of molecules in the nanopore.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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. PMID:26782020

  8. Microfluidic direct writer with integrated declogging mechanism for fabricating cell-laden hydrogel constructs.

    PubMed

    Ghorbanian, Setareh; Qasaimeh, Mohammad A; Akbari, Mohsen; Tamayol, Ali; Juncker, David

    2014-06-01

    Cell distribution and nutrient supply in 3D cell-laden hydrogel scaffolds are critical and should mimic the in vivo cellular environment, but been difficult to control with conventional fabrication methods. Here, we present a microfluidic direct writer (MFDW) to construct 3D cell-laden hydrogel structures with openings permitting media exchange. The MFDW comprises a monolithic microfluidic head, which delivers coaxial streams of cell-laden sodium alginate and calcium chloride solutions to form hydrogel fibers. Fiber diameter is controlled by adjusting the ratio of the volumetric flow rates. The MFDW head is mounted on a motorized stage, which is automatically controlled and moves at a speed synchronized with the speed of fiber fabrication. Head geometry, flow rates, and viscosity of the writing solutions were optimized to prevent the occurrence of curling and bulging. For continuous use, a highly reliable process is needed, which was accomplished with the integration of a declogging conduit supplying a solvent to dissolve the clogging gel. The MFDW was used for layer-by-layer fabrication of simple 3D structures with encapsulated cells. Assembly of 3D structures with distinct fibers is demonstrated by alternatively delivering two different alginate gel solutions. The MFDW head can be built rapidly and easily, and will allow 3D constructs for tissue engineering to be fabricated with multiple hydrogels and cell types. PMID:24590741

  9. Controlled Fabrication of Bioactive Microfibers for Creating Tissue Constructs Using Microfluidic Techniques.

    PubMed

    Cheng, Yao; Yu, Yunru; Fu, Fanfan; Wang, Jie; Shang, Luoran; Gu, Zhongze; Zhao, Yuanjin

    2016-01-20

    The fabrication of heterogeneous microstructures, which exert precise control over the distribution of different cell types within biocompatible constructs, is important for many tissue engineering applications. Here, bioactive microfibers with tunable morphologies, structures, and components are generated and employed for creating different tissue constructs. Multibarrel capillary microfluidics with multiple laminar flows are used for continuously spinning these microfibers. With an immediate gelation reaction of the cell dispersed alginate solutions, the cell-laden alginate microfibers with the tunable morphologies and structures as the designed multiple laminar flows can be generated. The performances of the microfibers in cell culture are improved by incorporating bioactive polymers, such as extracellular matrix (ECM) or methacrylated gelatin (GelMA), into the alginate. It is demonstrated that a series of complex three-dimensional (3D) architectural cellular buildings, including biomimic vessels and scaffolds, can be created using these bioactive microfibers. PMID:26741731

  10. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  11. Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting

    PubMed Central

    Hrabe, Nikolas W.; Heinl, Peter; Bordia, Rajendra K.; Körner, Carolin; Fernandes, Russell J.

    2013-01-01

    Regular 3D periodic porous Ti-6Al-4 V structures were fabricated by the selective electron beam melting method (EBM) over a range of relative densities (0.17–0.40) and pore sizes (500–1500 μm). Structures were seeded with human osteoblast-like cells (SAOS-2) and cultured for four weeks. Cells multiplied within these structures and extracellular matrix collagen content increased. Type I and type V collagens typically synthesized by osteoblasts were deposited in the newly formed matrix with time in culture. High magnification scanning electron microscopy revealed cells attached to surfaces on the interior of the structures with an increasingly fibrous matrix. The in-vitro results demonstrate that the novel EBM-processed porous structures, designed to address the effect of stress-shielding, are conducive to osteoblast attachment, proliferation and deposition of a collagenous matrix characteristic of bone. PMID:23869614

  12. Efficacy of rhBMP-2 loaded PCL/PLGA/β-TCP guided bone regeneration membrane fabricated by 3D printing technology for reconstruction of calvaria defects in rabbit.

    PubMed

    Shim, Jin-Hyung; Yoon, Min-Chul; Jeong, Chang-Mo; Jang, Jinah; Jeong, Sung-In; Cho, Dong-Woo; Huh, Jung-Bo

    2014-12-01

    We successfully fabricated a three-dimensional (3D) printing-based PCL/PLGA/β-TCP guided bone regeneration (GBR) membrane that slowly released rhBMP-2. To impregnate the GBR membrane with intact rhBMP-2, collagen solution encapsulating rhBMP-2 (5 µg ml(-1)) was infused into pores of a PCL/PLGA/β-TCP membrane constructed using a 3D printing system with four dispensing heads. In a release profile test, sustained release of rhBMP-2 was observed for up to 28 d. To investigate the efficacy of the GBR membrane on bone regeneration, PCL/PLGA/β-TCP membranes with or without rhBMP-2 were implanted in an 8 mm calvaria defect of rabbits. Bone formation was evaluated at weeks 4 and 8 histologically and histomorphometrically. A space making ability of the GBR membrane was successfully maintained in both groups, and significantly more new bone was formed at post-implantation weeks 4 and 8 by rhBMP-2 loaded GBR membranes. Interestingly, implantation with rhBMP-2 loaded GBR membranes led to almost entire healing of calvaria defects within 8 weeks. PMID:25384105

  13. 3-D Technology Approaches for Biological Ecologies

    NASA Astrophysics Data System (ADS)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  14. Alginate and alginate/gelatin microspheres for human adipose-derived stem cell encapsulation and differentiation.

    PubMed

    Yao, Rui; Zhang, Renji; Luan, Jie; Lin, Feng

    2012-06-01

    Human adipose-derived stem cells (hADSC) encapsulated in alginate and alginate/gelatin microspheres with adjustable properties were fabricated via an improved microsphere generating device. The mechanism of the device, porous property, swelling behavior of the microspheres and hADSC proliferation as well as adipogenic differentiation were studied extensively. Microspheres with high-ratio evenly distributed adipocytes could be obtained by utilizing the proper matrix material and manufacturing parameters. The adipocyte/hADSC microspheres were a sound in vitro mimicking of a natural fat lobule and therefore a good candidate for adipose tissue engineering and regenerative medicine. PMID:22556122

  15. Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and methylene blue.

    PubMed

    Jung, Kyung-Won; Choi, Brian Hyun; Hwang, Min-Jin; Jeong, Tae-Un; Ahn, Kyu-Hong

    2016-11-01

    Biomass-based granular activated carbon was successfully prepared by entrapping activated carbon powder derived from spent coffee grounds into calcium-alginate beads (SCG-GAC) for the removal of acid orange 7 (AO7) and methylene blue (MB) from aqueous media. The dye adsorption process is highly pH-dependent and essentially independent of ionic effects. The adsorption kinetics was satisfactorily described by the pore diffusion model, which revealed that pore diffusion was the rate-limiting step during the adsorption process. The equilibrium isotherm and isosteric heat of adsorption indicate that SCG-GAC possesses an energetically heterogeneous surface and operates via endothermic process in nature. The maximum adsorption capacities of SCG-GAC for AO7 (pH 3.0) and MB (pH 11.0) adsorption were found to be 665.9 and 986.8mg/g at 30°C, respectively. Lastly, regeneration tests further confirmed that SCG-GAC has promising potential in its reusability, showing removal efficiency of more than 80% even after seven consecutive cycles. PMID:27494099

  16. TRACE 3-D documentation

    SciTech Connect

    Crandall, K.R.

    1987-08-01

    TRACE 3-D is an interactive beam-dynamics program that calculates the envelopes of a bunched beam, including linear space-charge forces, through a user-defined transport system. TRACE 3-D provides an immediate graphics display of the envelopes and the phase-space ellipses and allows nine types of beam-matching options. This report describes the beam-dynamics calculations and gives detailed instruction for using the code. Several examples are described in detail.

  17. Three-dimensional bioprinting of complex cell laden alginate hydrogel structures.

    PubMed

    Tabriz, Atabak Ghanizadeh; Hermida, Miguel A; Leslie, Nicholas R; Shu, Wenmiao

    2015-01-01

    Different bioprinting techniques have been used to produce cell-laden alginate hydrogel structures, however these approaches have been limited to 2D or simple three-dimension (3D) structures. In this study, a new extrusion based bioprinting technique was developed to produce more complex alginate hydrogel structures. This was achieved by dividing the alginate hydrogel cross-linking process into three stages: primary calcium ion cross-linking for printability of the gel, secondary calcium cross-linking for rigidity of the alginate hydrogel immediately after printing and tertiary barium ion cross-linking for long-term stability of the alginate hydrogel in culture medium. Simple 3D structures including tubes were first printed to ensure the feasibility of the bioprinting technique and then complex 3D structures such as branched vascular structures were successfully printed. The static stiffness of the alginate hydrogel after printing was 20.18 ± 1.62 KPa which was rigid enough to sustain the integrity of the complex 3D alginate hydrogel structure during the printing. The addition of 60 mM barium chloride was found to significantly extend the stability of the cross-linked alginate hydrogel from 3 d to beyond 11 d without compromising the cellular viability. The results based on cell bioprinting suggested that viability of U87-MG cells was 93 ± 0.9% immediately after bioprinting and cell viability maintained above 88% ± 4.3% in the alginate hydrogel over the period of 11 d. PMID:26689257

  18. 3D-patterned polymer brush surfaces

    NASA Astrophysics Data System (ADS)

    Zhou, Xuechang; Liu, Xuqing; Xie, Zhuang; Zheng, Zijian

    2011-12-01

    Polymer brush-based three-dimensional (3D) structures are emerging as a powerful platform to engineer a surface by providing abundant spatially distributed chemical and physical properties. In this feature article, we aim to give a summary of the recent progress on the fabrication of 3D structures with polymer brushes, with a particular focus on the micro- and nanoscale. We start with a brief introduction on polymer brushes and the challenges to prepare their 3D structures. Then, we highlight the recent advances of the fabrication approaches on the basis of traditional polymerization time and grafting density strategies, and a recently developed feature density strategy. Finally, we provide some perspective outlooks on the future directions of engineering the 3D structures with polymer brushes.

  19. Fabrication of 3D carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Laera, Anna Maria; Mirenghi, Luciana; Schioppa, Monica; Nobile, Concetta; Capodieci, Laura; Grazia Scalone, Anna; Di Benedetto, Francesca; Tapfer, Leander

    2016-08-01

    We report on the synthesis and characterization of a hyperbranched polymer englobing single-wall carbon nanotubes (SWCNTs). This new material was obtained by using SWCNTs functionalized with carboxylic groups as starting reagent. The acid groups were firstly converted in acyl chloride moieties and afterwards were bound to hexamethylenediamine (HMDA) via formation of amide functionality. The acquired spectra of attenuated total reflectance and the analysis performed through x-ray photoelectron spectroscopy confirmed the amide bond formation. The hyperbranched polymer characterization was completed by using scanning and transmission electron microscopy, thermo-gravimetric analysis and Raman spectroscopy. The electron microscopy analyses showed the formation of an amorphous polymeric material englobing a dense network of SWCNTs without phase segregation, demonstrating that the reaction with HMDA allows a reorganization of SWCNTs in a complex three-dimensional network.

  20. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  1. Biocompatible 3D Matrix with Antimicrobial Properties.

    PubMed

    Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2016-01-01

    The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering. PMID:26805790

  2. Bootstrapping 3D fermions

    NASA Astrophysics Data System (ADS)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions < ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  3. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Calcium alginate is prepared...

  4. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Potassium alginate...

  5. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium alginate. 184.1724 Section 184.1724 Food and... Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate...

  6. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate is prepared by...

  7. 3D printed PLA-based scaffolds

    PubMed Central

    Serra, Tiziano; Mateos-Timoneda, Miguel A; Planell, Josep A; Navarro, Melba

    2013-01-01

    Rapid prototyping (RP), also known as additive manufacturing (AM), has been well received and adopted in the biomedical field. The capacity of this family of techniques to fabricate customized 3D structures with complex geometries and excellent reproducibility has revolutionized implantology and regenerative medicine. In particular, nozzle-based systems allow the fabrication of high-resolution polylactic acid (PLA) structures that are of interest in regenerative medicine. These 3D structures find interesting applications in the regenerative medicine field where promising applications including biodegradable templates for tissue regeneration purposes, 3D in vitro platforms for studying cell response to different scaffolds conditions and for drug screening are considered among others. Scaffolds functionality depends not only on the fabrication technique, but also on the material used to build the 3D structure, the geometry and inner architecture of the structure, and the final surface properties. All being crucial parameters affecting scaffolds success. This Commentary emphasizes the importance of these parameters in scaffolds’ fabrication and also draws the attention toward the versatility of these PLA scaffolds as a potential tool in regenerative medicine and other medical fields. PMID:23959206

  8. 3D printed microfluidics for biological applications.

    PubMed

    Ho, Chee Meng Benjamin; Ng, Sum Huan; Li, King Ho Holden; Yoon, Yong-Jin

    2015-01-01

    The term "Lab-on-a-Chip," is synonymous with describing microfluidic devices with biomedical applications. Even though microfluidics have been developing rapidly over the past decade, the uptake rate in biological research has been slow. This could be due to the tedious process of fabricating a chip and the absence of a "killer application" that would outperform existing traditional methods. In recent years, three dimensional (3D) printing has been drawing much interest from the research community. It has the ability to make complex structures with high resolution. Moreover, the fast building time and ease of learning has simplified the fabrication process of microfluidic devices to a single step. This could possibly aid the field of microfluidics in finding its "killer application" that will lead to its acceptance by researchers, especially in the biomedical field. In this paper, a review is carried out of how 3D printing helps to improve the fabrication of microfluidic devices, the 3D printing technologies currently used for fabrication and the future of 3D printing in the field of microfluidics. PMID:26237523

  9. Multiviewer 3D monitor

    NASA Astrophysics Data System (ADS)

    Kostrzewski, Andrew A.; Aye, Tin M.; Kim, Dai Hyun; Esterkin, Vladimir; Savant, Gajendra D.

    1998-09-01

    Physical Optics Corporation has developed an advanced 3-D virtual reality system for use with simulation tools for training technical and military personnel. This system avoids such drawbacks of other virtual reality (VR) systems as eye fatigue, headaches, and alignment for each viewer, all of which are due to the need to wear special VR goggles. The new system is based on direct viewing of an interactive environment. This innovative holographic multiplexed screen technology makes it unnecessary for the viewer to wear special goggles.

  10. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  11. Medical 3D Printing for the Radiologist.

    PubMed

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. PMID:26562233

  12. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  13. Towards antimicrobial yet bioactive Cu-alginate hydrogels.

    PubMed

    Madzovska-Malagurski, I; Vukasinovic-Sekulic, M; Kostic, D; Levic, S

    2016-01-01

    The simplest approach to enhance alginate hydrogel characteristics and functional properties is to replace the calcium in the process of alginate gelation with other metallic ions which are essential for living systems. Gelling of alginate with other ions and using modern encapsulation techniques can provide new delivery systems with required properties. Hence, in this study Cu-alginate hydrogels in the form of microbeads were produced by electrostatic extrusion using gelling solutions with Cu(II) concentrations in the range 13.5-270 mM and comprehensively characterized in vitro. The variation of gelling solution concentration influenced the microbead Cu(II) content, size, biomechanical properties, Cu(II) release and subsequently potential biomedical application. The formulations chosen for biomedical evaluation showed potential for antimicrobial and tissue engineering applications. Microbeads with higher Cu(II) loading (~100 μmol g(-1)) induced immediate bactericidal effects against Escherichia coli and Staphylococcus aureus. Conversely, Cu(II) release from microbeads with the Cu(II) content of ~60 μmol g(-1) was slower and they were suitable for promoting and maintaining chondrogenic phenotype of bovine calf chondrocytes in 3D culture. Results of this study have shown possibilities for tuning Cu-alginate properties for potential biomedical applications such as antimicrobial wound dressings, tissue engineering scaffolds or articular cartilage implants. PMID:27305176

  14. 3D polarimetric purity

    NASA Astrophysics Data System (ADS)

    Gil, José J.; San José, Ignacio

    2010-11-01

    From our previous definition of the indices of polarimetric purity for 3D light beams [J.J. Gil, J.M. Correas, P.A. Melero and C. Ferreira, Monogr. Semin. Mat. G. de Galdeano 31, 161 (2004)], an analysis of their geometric and physical interpretation is presented. It is found that, in agreement with previous results, the first parameter is a measure of the degree of polarization, whereas the second parameter (called the degree of directionality) is a measure of the mean angular aperture of the direction of propagation of the corresponding light beam. This pair of invariant, non-dimensional, indices of polarimetric purity contains complete information about the polarimetric purity of a light beam. The overall degree of polarimetric purity is obtained as a weighted quadratic average of the degree of polarization and the degree of directionality.

  15. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  16. 'Bonneville' in 3-D!

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Mars Exploration Rover Spirit took this 3-D navigation camera mosaic of the crater called 'Bonneville' after driving approximately 13 meters (42.7 feet) to get a better vantage point. Spirit's current position is close enough to the edge to see the interior of the crater, but high enough and far enough back to get a view of all of the walls. Because scientists and rover controllers are so pleased with this location, they will stay here for at least two more martian days, or sols, to take high resolution panoramic camera images of 'Bonneville' in its entirety. Just above the far crater rim, on the left side, is the rover's heatshield, which is visible as a tiny reflective speck.

  17. 3D bioprinting for engineering complex tissues.

    PubMed

    Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho

    2016-01-01

    Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies. PMID:26724184

  18. Interpenetrated Si-HPMC/alginate hydrogels as a potential scaffold for human tissue regeneration.

    PubMed

    Viguier, Alexia; Boyer, Cecile; Chassenieux, Christophe; Benyahia, Lazhar; Guicheux, Jérôme; Weiss, Pierre; Rethore, Gildas; Nicolai, Taco

    2016-05-01

    Interpenetrated gels of biocompatible polysaccharides alginate and silanized hydroxypropyl methyl cellulose (Si-HPMC) have been studied in order to assess their potential as scaffolds for the regeneration of human tissues. Si-HPMC networks were formed by reduction of the pH to neutral and alginate networks were formed by progressive in situ release of Ca(2+). Linear and non-linear mechanical properties of the mixed gels at different polymer and calcium concentrations were compared with those of the corresponding single gels. The alginate/Si-HPMC gels were found to be stiffer than pure Si-HPMC gels, but weaker and more deformable than pure alginate gels. No significant difference was found for the maximum stress at rupture measured during compression for all these gels. The degrees of swelling or contraction in excess water at pH 7 as well as the release of Ca(2+) was measured as a function of time. Pure alginate gels contracted by as much as 50 % and showed syneresis, which was much reduced or even eliminated for mixed gels. The important release of Ca(2+) upon ageing for pure alginate gels was much reduced for the mixed gels. Furthermore, results of cytocompatibility assays indicated that there was no cytotoxicity of Si-HPMC/alginate hydrogels in 2D and 3D culture of human SW1353 cells. The results show that using interpenetrated Si-HPMC/alginate gels has clear advantages over the use of single gels for application in tissue regeneration. PMID:27022979

  19. 3D Printing of Highly Stretchable and Tough Hydrogels into Complex, Cellularized Structures.

    PubMed

    Hong, Sungmin; Sycks, Dalton; Chan, Hon Fai; Lin, Shaoting; Lopez, Gabriel P; Guilak, Farshid; Leong, Kam W; Zhao, Xuanhe

    2015-07-15

    A 3D printable and highly stretchable tough hydrogel is developed by combining poly(ethylene glycol) and sodium alginate, which synergize to form a hydrogel tougher than natural cartilage. Encapsulated cells maintain high viability over a 7 d culture period and are highly deformed together with the hydrogel. By adding biocompatible nanoclay, the tough hydrogel is 3D printed in various shapes without requiring support material. PMID:26033288

  20. DNA Assembly in 3D Printed Fluidics.

    PubMed

    Patrick, William G; Nielsen, Alec A K; Keating, Steven J; Levy, Taylor J; Wang, Che-Wei; Rivera, Jaime J; Mondragón-Palomino, Octavio; Carr, Peter A; Voigt, Christopher A; Oxman, Neri; Kong, David S

    2015-01-01

    The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology. PMID:26716448

  1. DNA Assembly in 3D Printed Fluidics

    PubMed Central

    Patrick, William G.; Nielsen, Alec A. K.; Keating, Steven J.; Levy, Taylor J.; Wang, Che-Wei; Rivera, Jaime J.; Mondragón-Palomino, Octavio; Carr, Peter A.; Voigt, Christopher A.; Oxman, Neri; Kong, David S.

    2015-01-01

    The process of connecting genetic parts—DNA assembly—is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology. PMID:26716448

  2. Printing 3D dielectric elastomer actuators for soft robotics

    NASA Astrophysics Data System (ADS)

    Rossiter, Jonathan; Walters, Peter; Stoimenov, Boyko

    2009-03-01

    We present a new approach to the fabrication of soft dielectric elastomer actuators using a 3D printing process. Complete actuators including active membranes and support structures can be 3D printed in one go, resulting in a great improvement in fabrication speed and increases in accuracy and consistency. We describe the fabrication process and present force and displacement results for a double-membrane antagonistic actuator. In this structure controlled prestrain is applied by the simple process of pressing together two printed actuator halves. The development of 3D printable soft actuators will have a large impact on many application areas including engineering, medicine and the emerging field of soft robotics.

  3. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  4. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  5. Inclined nanoimprinting lithography-based 3D nanofabrication

    NASA Astrophysics Data System (ADS)

    Liu, Zhan; Bucknall, David G.; Allen, Mark G.

    2011-06-01

    We report a 'top-down' 3D nanofabrication approach combining non-conventional inclined nanoimprint lithography (INIL) with reactive ion etching (RIE), contact molding and 3D metal nanotransfer printing (nTP). This integration of processes enables the production and conformal transfer of 3D polymer nanostructures of varying heights to a variety of other materials including a silicon-based substrate, a silicone stamp and a metal gold (Au) thin film. The process demonstrates the potential of reduced fabrication cost and complexity compared to existing methods. Various 3D nanostructures in technologically useful materials have been fabricated, including symmetric and asymmetric nanolines, nanocircles and nanosquares. Such 3D nanostructures have potential applications such as angle-resolved photonic crystals, plasmonic crystals and biomimicking anisotropic surfaces. This integrated INIL-based strategy shows great promise for 3D nanofabrication in the fields of photonics, plasmonics and surface tribology.

  6. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  7. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  8. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  9. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  10. 21 CFR 184.1610 - Potassium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No. 9005-36-1) is the potassium salt of alginic acid, a natural polyuronide constituent of certain...

  11. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  12. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  13. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... Specific Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown...

  14. Medical Applications for 3D Printing: Current and Projected Uses.

    PubMed

    Ventola, C Lee

    2014-10-01

    3D printing is expected to revolutionize health care through uses in tissue and organ fabrication; creation of customized prosthetics, implants, and anatomical models; and pharmaceutical research regarding drug dosage forms, delivery, and discovery. PMID:25336867

  15. 3D-printed microfluidic devices.

    PubMed

    Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-01

    Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices. PMID:27321137

  16. Multifunctional, Highly Flexible, Free-Standing 3D Polypyrrole Foam.

    PubMed

    Wang, Chunhui; Ding, Yujie; Yuan, Ye; Cao, Anyuan; He, Xiaodong; Peng, Qingyu; Li, Yibin

    2016-08-01

    Multifunctional, highly flexible 3D polypyrrole (PPy) foam is fabricated via a simple electrodeposition method by using nickel foam as the template. The 3D PPy foam has a unique interior structure and is robust enough to manipulate directly. PMID:27357260

  17. Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism

    PubMed Central

    Horniblow, Richard D.; Dowle, Miriam; Iqbal, Tariq H.; Latunde-Dada, Gladys O.; Palmer, Richard E.

    2015-01-01

    Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease. PMID:26378798

  18. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2010-12-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  19. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2011-05-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  20. Microbial alginate production, modification and its applications

    PubMed Central

    Hay, Iain D; Rehman, Zahid Ur; Moradali, M Fata; Wang, Yajie; Rehm, Bernd H A

    2013-01-01

    Alginate is an important polysaccharide used widely in the food, textile, printing and pharmaceutical industries for its viscosifying, and gelling properties. All commercially produced alginates are isolated from farmed brown seaweeds. These algal alginates suffer from heterogeneity in composition and material properties. Here, we will discuss alginates produced by bacteria; the molecular mechanisms involved in their biosynthesis; and the potential to utilize these bacterially produced or modified alginates for high-value applications where defined material properties are required. PMID:24034361

  1. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  2. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  3. Alginate: properties and biomedical applications

    PubMed Central

    Lee, Kuen Yong; Mooney, David J.

    2011-01-01

    Alginate is a biomaterial that has found numerous applications in biomedical science and engineering due to its favorable properties, including biocompatibility and ease of gelation. Alginate hydrogels have been particularly attractive in wound healing, drug delivery, and tissue engineering applications to date, as these gels retain structural similarity to the extracellular matrices in tissues and can be manipulated to play several critical roles. This review will provide a comprehensive overview of general properties of alginate and its hydrogels, their biomedical applications, and suggest new perspectives for future studies with these polymers. PMID:22125349

  4. Fabrication

    NASA Technical Reports Server (NTRS)

    Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

    1992-01-01

    What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

  5. 3D Printed Molecules and Extended Solid Models for Teaching Symmetry and Point Groups

    ERIC Educational Resources Information Center

    Scalfani, Vincent F.; Vaid, Thomas P.

    2014-01-01

    Tangible models help students and researchers visualize chemical structures in three dimensions (3D). 3D printing offers a unique and straightforward approach to fabricate plastic 3D models of molecules and extended solids. In this article, we prepared a series of digital 3D design files of molecular structures that will be useful for teaching…

  6. 3D Printing in Zero-G ISS Technology Demonstration

    NASA Technical Reports Server (NTRS)

    Werkheiser, Niki; Cooper, Kenneth C.; Edmunson, Jennifer E.; Dunn, Jason; Snyder, Michael

    2013-01-01

    The National Aeronautics and Space Administration (NASA) has a long term strategy to fabricate components and equipment on-demand for manned missions to the Moon, Mars, and beyond. To support this strategy, NASA's Marshall Space Fligth Center (MSFC) and Made in Space, Inc. are developing the 3D Printing In Zero-G payload as a Technology Demonstration for the International Space Station (ISS). The 3D Printing In Zero-G experiment ('3D Print') will be the frst machine to perform 3D printing in space.

  7. Highly compressible 3D periodic graphene aerogel microlattices.

    PubMed

    Zhu, Cheng; Han, T Yong-Jin; Duoss, Eric B; Golobic, Alexandra M; Kuntz, Joshua D; Spadaccini, Christopher M; Worsley, Marcus A

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  8. Highly compressible 3D periodic graphene aerogel microlattices

    PubMed Central

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  9. 3D-printing technologies for electrochemical applications.

    PubMed

    Ambrosi, Adriano; Pumera, Martin

    2016-05-21

    Since its conception during the 80s, 3D-printing, also known as additive manufacturing, has been receiving unprecedented levels of attention and interest from industry and research laboratories. This is in addition to end users, who have benefited from the pervasiveness of desktop-size and relatively cheap printing machines available. 3D-printing enables almost infinite possibilities for rapid prototyping. Therefore, it has been considered for applications in numerous research fields, ranging from mechanical engineering, medicine, and materials science to chemistry. Electrochemistry is another branch of science that can certainly benefit from 3D-printing technologies, paving the way for the design and fabrication of cheaper, higher performing, and ubiquitously available electrochemical devices. Here, we aim to provide a general overview of the most commonly available 3D-printing methods along with a review of recent electrochemistry related studies adopting 3D-printing as a possible rapid prototyping fabrication tool. PMID:27048921

  10. Highly compressible 3D periodic graphene aerogel microlattices

    SciTech Connect

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-22

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Ultimately, adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

  11. Emerging Applications of Bedside 3D Printing in Plastic Surgery.

    PubMed

    Chae, Michael P; Rozen, Warren M; McMenamin, Paul G; Findlay, Michael W; Spychal, Robert T; Hunter-Smith, David J

    2015-01-01

    Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing

  12. Emerging Applications of Bedside 3D Printing in Plastic Surgery

    PubMed Central

    Chae, Michael P.; Rozen, Warren M.; McMenamin, Paul G.; Findlay, Michael W.; Spychal, Robert T.; Hunter-Smith, David J.

    2015-01-01

    Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing

  13. Modular 3-D Transport model

    EPA Science Inventory

    MT3D was first developed by Chunmiao Zheng in 1990 at S.S. Papadopulos & Associates, Inc. with partial support from the U.S. Environmental Protection Agency (USEPA). Starting in 1990, MT3D was released as a pubic domain code from the USEPA. Commercial versions with enhanced capab...

  14. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  15. LLNL-Earth3D

    Energy Science and Technology Software Center (ESTSC)

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  16. [3-D ultrasound in gastroenterology].

    PubMed

    Zoller, W G; Liess, H

    1994-06-01

    Three-dimensional (3D) sonography represents a development of noninvasive diagnostic imaging by real-time two-dimensional (2D) sonography. The use of transparent rotating scans, comparable to a block of glass, generates a 3D effect. The objective of the present study was to optimate 3D presentation of abdominal findings. Additional investigations were made with a new volumetric program to determine the volume of selected findings of the liver. The results were compared with the estimated volumes of 2D sonography and 2D computer tomography (CT). For the processing of 3D images, typical parameter constellations were found for the different findings, which facilitated processing of 3D images. In more than 75% of the cases examined we found an optimal 3D presentation of sonographic findings with respect to the evaluation criteria developed by us for the 3D imaging of processed data. Great differences were found for the estimated volumes of the findings of the liver concerning the three different techniques applied. 3D ultrasound represents a valuable method to judge morphological appearance in abdominal findings. The possibility of volumetric measurements enlarges its potential diagnostic significance. Further clinical investigations are necessary to find out if definite differentiation between benign and malign findings is possible. PMID:7919882

  17. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  18. 3D World Building System

    ScienceCinema

    None

    2014-02-26

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  19. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  20. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  1. 3D Printed Micro Free-Flow Electrophoresis Device.

    PubMed

    Anciaux, Sarah K; Geiger, Matthew; Bowser, Michael T

    2016-08-01

    The cost, time, and restrictions on creative flexibility associated with current fabrication methods present significant challenges in the development and application of microfluidic devices. Additive manufacturing, also referred to as three-dimensional (3D) printing, provides many advantages over existing methods. With 3D printing, devices can be made in a cost-effective manner with the ability to rapidly prototype new designs. We have fabricated a micro free-flow electrophoresis (μFFE) device using a low-cost, consumer-grade 3D printer. Test prints were performed to determine the minimum feature sizes that could be reproducibly produced using 3D printing fabrication. Microfluidic ridges could be fabricated with dimensions as small as 20 μm high × 640 μm wide. Minimum valley dimensions were 30 μm wide × 130 μm wide. An acetone vapor bath was used to smooth acrylonitrile-butadiene-styrene (ABS) surfaces and facilitate bonding of fully enclosed channels. The surfaces of the 3D-printed features were profiled and compared to a similar device fabricated in a glass substrate. Stable stream profiles were obtained in a 3D-printed μFFE device. Separations of fluorescent dyes in the 3D-printed device and its glass counterpart were comparable. A μFFE separation of myoglobin and cytochrome c was also demonstrated on a 3D-printed device. Limits of detection for rhodamine 110 were determined to be 2 and 0.3 nM for the 3D-printed and glass devices, respectively. PMID:27377354

  2. High-throughput three-dimensional (3D) lithographic microfabrication in biomedical applications

    NASA Astrophysics Data System (ADS)

    Kim, Daekeun; So, Peter T. C.

    2010-02-01

    Two-photon excitation microfabrication has been shown to be useful in the field of photonics and biomedicine. It generates 3D microstructures and provides sub-diffraction fabrication resolution. Nevertheless, laser direct writing, the most popular two-photon fabrication technique, has slow fabrication speed, and its applications are limited to prototyping. In this proceeding, we propose high-throughput 3D lithographic microfabrication system based on depthresolved wide-field illumination and build several 3D microstructures with SU-8. Through these fabrications, 3D lithographic microfabrication has scalable function and high-throughput capability. It also has the potential for fabricating 3D microstructure in biomedical applications, such as intertwining channels in 3D microfluidic devices for biomedical analysis and 3D cell patterning in the tissue scaffolds.

  3. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  4. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  5. Unit cell geometry of 3-D braided structures

    NASA Technical Reports Server (NTRS)

    Du, Guang-Wu; Ko, Frank K.

    1993-01-01

    The traditional approach used in modeling of composites reinforced by three-dimensional (3-D) braids is to assume a simple unit cell geometry of a 3-D braided structure with known fiber volume fraction and orientation. In this article, we first examine 3-D braiding methods in the light of braid structures, followed by the development of geometric models for 3-D braids using a unit cell approach. The unit cell geometry of 3-D braids is identified and the relationship of structural parameters such as yarn orientation angle and fiber volume fraction with the key processing parameters established. The limiting geometry has been computed by establishing the point at which yarns jam against each other. Using this factor makes it possible to identify the complete range of allowable geometric arrangements for 3-D braided preforms. This identified unit cell geometry can be translated to mechanical models which relate the geometrical properties of fabric preforms to the mechanical responses of composite systems.

  6. Defining an optimal surface chemistry for pluripotent stem cell culture in 2D and 3D

    NASA Astrophysics Data System (ADS)

    Zonca, Michael R., Jr.

    Surface chemistry is critical for growing pluripotent stem cells in an undifferentiated state. There is great potential to engineer the surface chemistry at the nanoscale level to regulate stem cell adhesion. However, the challenge is to identify the optimal surface chemistry of the substrata for ES cell attachment and maintenance. Using a high-throughput polymerization and screening platform, a chemically defined, synthetic polymer grafted coating that supports strong attachment and high expansion capacity of pluripotent stem cells has been discovered using mouse embryonic stem (ES) cells as a model system. This optimal substrate, N-[3-(Dimethylamino)propyl] methacrylamide (DMAPMA) that is grafted on 2D synthetic poly(ether sulfone) (PES) membrane, sustains the self-renewal of ES cells (up to 7 passages). DMAPMA supports cell attachment of ES cells through integrin beta1 in a RGD-independent manner and is similar to another recently reported polymer surface. Next, DMAPMA has been able to be transferred to 3D by grafting to synthetic, polymeric, PES fibrous matrices through both photo-induced and plasma-induced polymerization. These 3D modified fibers exhibited higher cell proliferation and greater expression of pluripotency markers of mouse ES cells than 2D PES membranes. Our results indicated that desirable surfaces in 2D can be scaled to 3D and that both surface chemistry and structural dimension strongly influence the growth and differentiation of pluripotent stem cells. Lastly, the feasibility of incorporating DMAPMA into a widely used natural polymer, alginate, has been tested. Novel adhesive alginate hydrogels have been successfully synthesized by either direct polymerization of DMAPMA and methacrylic acid blended with alginate, or photo-induced DMAPMA polymerization on alginate nanofibrous hydrogels. In particular, DMAPMA-coated alginate hydrogels support strong ES cell attachment, exhibiting a concentration dependency of DMAPMA. This research provides a

  7. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  8. Arena3D: visualization of biological networks in 3D

    PubMed Central

    Pavlopoulos, Georgios A; O'Donoghue, Seán I; Satagopam, Venkata P; Soldatos, Theodoros G; Pafilis, Evangelos; Schneider, Reinhard

    2008-01-01

    Background Complexity is a key problem when visualizing biological networks; as the number of entities increases, most graphical views become incomprehensible. Our goal is to enable many thousands of entities to be visualized meaningfully and with high performance. Results We present a new visualization tool, Arena3D, which introduces a new concept of staggered layers in 3D space. Related data – such as proteins, chemicals, or pathways – can be grouped onto separate layers and arranged via layout algorithms, such as Fruchterman-Reingold, distance geometry, and a novel hierarchical layout. Data on a layer can be clustered via k-means, affinity propagation, Markov clustering, neighbor joining, tree clustering, or UPGMA ('unweighted pair-group method with arithmetic mean'). A simple input format defines the name and URL for each node, and defines connections or similarity scores between pairs of nodes. The use of Arena3D is illustrated with datasets related to Huntington's disease. Conclusion Arena3D is a user friendly visualization tool that is able to visualize biological or any other network in 3D space. It is free for academic use and runs on any platform. It can be downloaded or lunched directly from . Java3D library and Java 1.5 need to be pre-installed for the software to run. PMID:19040715

  9. Fdf in US3D

    NASA Astrophysics Data System (ADS)

    Otis, Collin; Ferrero, Pietro; Candler, Graham; Givi, Peyman

    2013-11-01

    The scalar filtered mass density function (SFMDF) methodology is implemented into the computer code US3D. This is an unstructured Eulerian finite volume hydrodynamic solver and has proven very effective for simulation of compressible turbulent flows. The resulting SFMDF-US3D code is employed for large eddy simulation (LES) on unstructured meshes. Simulations are conducted of subsonic and supersonic flows under non-reacting and reacting conditions. The consistency and the accuracy of the simulated results are assessed along with appraisal of the overall performance of the methodology. The SFMDF-US3D is now capable of simulating high speed flows in complex configurations.

  10. Impact of alginate concentration on the viability, cryostorage, and angiogenic activity of encapsulated fibroblasts.

    PubMed

    Mohanty, Swetaparna; Wu, Yang; Chakraborty, Nilay; Mohanty, Pravansu; Ghosh, Gargi

    2016-08-01

    Cryopreservation or cryostorage of tissue engineered constructs can enhance the off-the shelf availability of these products and thus can potentially facilitate the commercialization or clinical translation of tissue engineered products. Encapsulation of cells within hydrogel matrices, in particular alginate, is widely used for fabrication of tissue engineered constructs. While previous studies have explored the cryopreservation response of cells encapsulated within alginate matrices, systematic investigation of the impact of alginate concentration on the metabolic activity and functionality of cryopreserved cells is lacking. The objective of the present work is to determine the metabolic and angiogenic activity of cryopreserved human dermal fibroblasts encapsulated within 1.0%, 1.5% and 2.0% (w/v) alginate matrices. In addition, the goal is to compare the efficacy of dimethyl sulfoxide (DMSO) and trehalose as cryoprotectant. Our study revealed that the concentration of alginate plays a significant role in the cryopreservation response of encapsulated cells. The lowest metabolic activity of the cryopreserved cells was observed in 1% alginate microspheres. When higher concentration of alginate was utilized for cell encapsulation, the metabolic and angiogenic activity of the cells frozen in the absence of cryoprotectants was comparable to that observed in the presence of DMSO or trehalose. PMID:27157752

  11. Laser printing of 3D metallic interconnects

    NASA Astrophysics Data System (ADS)

    Beniam, Iyoel; Mathews, Scott A.; Charipar, Nicholas A.; Auyeung, Raymond C. Y.; Piqué, Alberto

    2016-04-01

    The use of laser-induced forward transfer (LIFT) techniques for the printing of functional materials has been demonstrated for numerous applications. The printing gives rise to patterns, which can be used to fabricate planar interconnects. More recently, various groups have demonstrated electrical interconnects from laser-printed 3D structures. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or of pastes containing dispersed metallic particles. However, the generated 3D structures do not posses the same metallic conductivity as a bulk metal interconnect of the same cross-section and length as those formed by wire bonding or tab welding. An alternative is to laser transfer entire 3D structures using a technique known as lase-and-place. Lase-and-place is a LIFT process whereby whole components and parts can be transferred from a donor substrate onto a desired location with one single laser pulse. This paper will describe the use of LIFT to laser print freestanding, solid metal foils or beams precisely over the contact pads of discrete devices to interconnect them into fully functional circuits. Furthermore, this paper will also show how the same laser can be used to bend or fold the bulk metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief for the circuits under flexing or during motion from thermal mismatch. These interconnect "ridges" can span wide gaps (on the order of a millimeter) and accommodate height differences of tens of microns between adjacent devices. Examples of these laser printed 3D metallic bridges and their role in the development of next generation electronics by additive manufacturing will be presented.

  12. The upcoming 3D-printing revolution in microfluidics.

    PubMed

    Bhattacharjee, Nirveek; Urrios, Arturo; Kang, Shawn; Folch, Albert

    2016-05-21

    In the last two decades, the vast majority of microfluidic systems have been built in poly(dimethylsiloxane) (PDMS) by soft lithography, a technique based on PDMS micromolding. A long list of key PDMS properties have contributed to the success of soft lithography: PDMS is biocompatible, elastomeric, transparent, gas-permeable, water-impermeable, fairly inexpensive, copyright-free, and rapidly prototyped with high precision using simple procedures. However, the fabrication process typically involves substantial human labor, which tends to make PDMS devices difficult to disseminate outside of research labs, and the layered molding limits the 3D complexity of the devices that can be produced. 3D-printing has recently attracted attention as a way to fabricate microfluidic systems due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. Resins with properties approaching those of PDMS are being developed. Here we review past and recent efforts in 3D-printing of microfluidic systems. We compare the salient features of PDMS molding with those of 3D-printing and we give an overview of the critical barriers that have prevented the adoption of 3D-printing by microfluidic developers, namely resolution, throughput, and resin biocompatibility. We also evaluate the various forces that are persuading researchers to abandon PDMS molding in favor of 3D-printing in growing numbers. PMID:27101171

  13. 3D IC for Future HEP Detectors

    SciTech Connect

    Thom, J.; Lipton, R.; Heintz, U.; Johnson, M.; Narain, M.; Badman, R.; Spiegel, L.; Triphati, M.; Deptuch, G.; Kenney, C.; Parker, S.; Ye, Z.; Siddons, D.

    2014-11-07

    Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. Here we describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This also includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

  14. 3D IC for future HEP detectors

    NASA Astrophysics Data System (ADS)

    Thom, J.; Lipton, R.; Heintz, U.; Johnson, M.; Narain, M.; Badman, R.; Spiegel, L.; Triphati, M.; Deptuch, G.; Kenney, C.; Parker, S.; Ye, Z.; Siddons, D. P.

    2014-11-01

    Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

  15. Wavefront construction in 3-D

    SciTech Connect

    Chilcoat, S.R. Hildebrand, S.T.

    1995-12-31

    Travel time computation in inhomogeneous media is essential for pre-stack Kirchhoff imaging in areas such as the sub-salt province in the Gulf of Mexico. The 2D algorithm published by Vinje, et al, has been extended to 3D to compute wavefronts in complicated inhomogeneous media. The 3D wavefront construction algorithm provides many advantages over conventional ray tracing and other methods of computing travel times in 3D. The algorithm dynamically maintains a reasonably consistent ray density without making a priori guesses at the number of rays to shoot. The determination of caustics in 3D is a straight forward geometric procedure. The wavefront algorithm also enables the computation of multi-valued travel time surfaces.

  16. Heterodyne 3D ghost imaging

    NASA Astrophysics Data System (ADS)

    Yang, Xu; Zhang, Yong; Yang, Chenghua; Xu, Lu; Wang, Qiang; Zhao, Yuan

    2016-06-01

    Conventional three dimensional (3D) ghost imaging measures range of target based on pulse fight time measurement method. Due to the limit of data acquisition system sampling rate, range resolution of the conventional 3D ghost imaging is usually low. In order to take off the effect of sampling rate to range resolution of 3D ghost imaging, a heterodyne 3D ghost imaging (HGI) system is presented in this study. The source of HGI is a continuous wave laser instead of pulse laser. Temporal correlation and spatial correlation of light are both utilized to obtain the range image of target. Through theory analysis and numerical simulations, it is demonstrated that HGI can obtain high range resolution image with low sampling rate.

  17. Structural Characterization of Sodium Alginate and Calcium Alginate.

    PubMed

    Hecht, Hadas; Srebnik, Simcha

    2016-06-13

    Alginate readily aggregates and forms a physical gel in the presence of cations. The association of the chains, and ultimately gel structure and mechanics, depends not only on ion type, but also on the sequence and composition of the alginate chain that ultimately determines its stiffness. Chain flexibility is generally believed to decrease with guluronic residue content, but it is also known that both polymannuronate and polyguluronate blocks are stiffer than heteropolymeric blocks. In this work, we use atomistic molecular dynamics simulation to primarily explore the association and aggregate structure of different alginate chains under various Ca(2+) concentrations and for different alginate chain composition. We show that Ca(2+) ions in general facilitate chain aggregation and gelation. However, aggregation is predominantly affected by alginate monomer composition, which is found to correlate with chain stiffness under certain solution conditions. In general, greater fractions of mannuronic monomers are found to increase chain flexibility of heteropolymer chains. Furthermore, differences in chain guluronic acid content are shown to lead to different interchain association mechanisms, such as lateral association, zipper mechanism, and entanglement, where the mannuronic residues are shown to operate as an elasticity moderator and therefore promote chain association. PMID:27177209

  18. Combinatorial 3D Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  19. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    PubMed

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. PMID:26453887

  20. Personalized development of human organs using 3D printing technology.

    PubMed

    Radenkovic, Dina; Solouk, Atefeh; Seifalian, Alexander

    2016-02-01

    3D printing is a technique of fabricating physical models from a 3D volumetric digital image. The image is sliced and printed using a specific material into thin layers, and successive layering of the material produces a 3D model. It has already been used for printing surgical models for preoperative planning and in constructing personalized prostheses for patients. The ultimate goal is to achieve the development of functional human organs and tissues, to overcome limitations of organ transplantation created by the lack of organ donors and life-long immunosuppression. We hypothesized a precision medicine approach to human organ fabrication using 3D printed technology, in which the digital volumetric data would be collected by imaging of a patient, i.e. CT or MRI images followed by mathematical modeling to create a digital 3D image. Then a suitable biocompatible material, with an optimal resolution for cells seeding and maintenance of cell viability during the printing process, would be printed with a compatible printer type and finally implanted into the patient. Life-saving operations with 3D printed implants were already performed in patients. However, several issues need to be addressed before translational application of 3D printing into clinical medicine. These are vascularization, innervation, and financial cost of 3D printing and safety of biomaterials used for the construct. PMID:26826637

  1. 3D Printing: 3D Printing of Conductive Complex Structures with In Situ Generation of Silver Nanoparticles (Adv. Mater. 19/2016).

    PubMed

    Fantino, Erika; Chiappone, Annalisa; Roppolo, Ignazio; Manfredi, Diego; Bongiovanni, Roberta; Pirri, Candido Fabrizio; Calignano, Flaviana

    2016-05-01

    On page 3712, E. Fantino, A. Chiappone, and co-workers fabricate conductive 3D hybrid structures by coupling the photo-reduction of metal precursors with 3D printing technology. The generated structures consist of metal nanoparticles embedded in a polymer matrix shaped into complex multilayered architectures. 3D conductive structures are fabricated with a digital light-processing printer incorporating silver salt into photocurable formulations. PMID:27167030

  2. Incorporation of magnesium ions into photo-crosslinked alginate hydrogel enhanced cell adhesion ability.

    PubMed

    Yin, Miao; Xu, Fei; Ding, Huifen; Tan, Fei; Song, Fangfang; Wang, Jiawei

    2015-09-01

    Photo-crosslinked alginate hydrogel attracts wide interest in tissue engineering because of its excellent controllability and stability. However, its highly hydrophilic property makes cell adhesion difficult. Plenty of studies have confirmed that magnesium ions (Mg(2+) ) can efficiently improve the attachment of osteoblasts. In this study, for the first time, we fabricated a durable, crosslinked, alginate hydrogel with a dual-crosslinking network. Photo-crosslinked alginate hydrogel was chosen as the basic backbone, and various amounts of Mg(2+) were incorporated into the hydrogel through ionic crosslinking. The results showed that the physicochemical properties of the hydrogels, including surface structure, composition, swelling ratio, ion release and elastic modulus, could be well tuned by controlling the amount of Mg(2+) incorporated. In addition, a certain amount of Mg(2+) significantly improved the attachment and spread of osteoblasts on the hydrogels. These characteristics make Mg(2+) -incorporated photo-crosslinked alginate hydrogel a promising scaffold for bone tissue engineering. PMID:25694165

  3. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is...

  4. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  5. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  6. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  7. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  8. 21 CFR 582.7610 - Potassium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  9. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  10. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1011 Alginic acid. (a) Alginic acid is a colloidal, hydrophilic polysaccharide obtained from...

  11. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  12. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  13. 21 CFR 184.1011 - Alginic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Alginic acid. 184.1011 Section 184.1011 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1011 Alginic acid. (a) Alginic acid is a colloidal,...

  14. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  15. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  16. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  17. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  18. 21 CFR 582.7724 - Sodium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium alginate. 582.7724 Section 582.7724 Food... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Stabilizers § 582.7724 Sodium alginate. (a) Product. Sodium alginate. (b) Conditions of use. This substance is generally recognized...

  19. Nonlinear elasticity of alginate gels

    NASA Astrophysics Data System (ADS)

    Hashemnejad, Seyed Meysam; Kundu, Santanu

    Alginate is a naturally occurring anionic polysaccharide extracted from brown algae. Because of biocompatibility, low toxicity, and simple gelation process, alginate gels are used in biomedical and food applications. Here, we report the rheological behavior of ionically crosslinked alginate gels, which are obtained by in situ gelation of alginates with calcium salts, in between two parallel plates of a rheometer. Strain stiffening behavior was captured using large amplitude oscillatory shear (LAOS) experiments. In addition, negative normal stress was observed for these gels, which has not been reported earlier for any polysaccharide networks. The magnitude of negative normal stress increases with applied strain and can exceed that of the shear stress at large strain. Rheological results fitted with a constitutive model that considers both stretching and bending of chains indicate that nonlinearity is likely related to the stretching of the chains between the crosslink junctions. The results provide an improved understanding of the deformation mechanism of ionically crosslinked alginate gel and the results will be important in developing synthetic extracellular matrix (ECM) from these materials.

  20. From 3D view to 3D print

    NASA Astrophysics Data System (ADS)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  1. Fabrication and electrochemical properties of hemisphere structured 3D Li(Li0.2Mn0.54Co0.13Ni0.13)O2 cathode thin film for all-solid-state lithium battery.

    PubMed

    Yim, H; Kong, W Y; Yoon, S J; Kim, Y C; Choi, J W

    2013-05-01

    The Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode thin films were deposited on planar, hemisphere, linked hemisphere, and isolated hemisphere structured Pt current collector thin films to investigate the effect of 3-dimensional (3-D) structure for the electrochemical properties of active cathode thin films. The films of linked hemisphere structure shows the highest initial discharge capacity of 140 microA h/cm2-microm which is better than those of planar (62 microA h/cm2-microm), hemisphere (94.6 microA h/cm2-microm), and isolated hemisphere (135 microA h/cm2-microm) films due to increase of surface area for cathode thin films. Linked hemisphere shows the biggest capacity and the best retention rate because 6 nanobridges of each hemisphere bring strong connection. PMID:23858879

  2. 3-D textile reinforcements in composite materials

    SciTech Connect

    Miravete, A.

    1999-11-01

    Laminated composite materials have been used in structural applications since the 1960s. However, their high cost and inability to accommodate fibers in the laminate`s thickness direction greatly reduce their damage tolerance and impact resistance. The second generation of materials--3-D textile reinforced composites--offers significant cost reduction, and by incorporating reinforcement in the thickness direction, dramatically increases damage tolerance and impact resistance. However, methods for predicting mechanical properties of 3-D textile reinforced composite materials tend to be more complex. These materials also have disadvantages--particularly in regard to crimps in the yarns--that require more research. Textile preforms, micro- and macromechanical modeling, manufacturing processes, and characterization all need further development. As researchers overcome these problems, this new generation of composites will emerge as a highly competitive family of materials. This book provides a state-of-the-art account of this promising technology. In it, top experts describe the manufacturing processes, highlight the advantages, identify the main applications, analyze methods for predicting mechanical properties, and detail various reinforcement strategies, including grid structure, knitted fabric composites, and the braiding technique. Armed with the information in this book, readers will be prepared to better exploit the advantages of 3-D textile reinforced composites, overcome its disadvantages, and contribute to the further development of the technology.

  3. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  4. 3D-printed microfluidic chips with patterned, cell-laden hydrogel constructs.

    PubMed

    Knowlton, Stephanie; Yu, Chu Hsiang; Ersoy, Fulya; Emadi, Sharareh; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-01

    Three-dimensional (3D) printing offers potential to fabricate high-throughput and low-cost fabrication of microfluidic devices as a promising alternative to traditional techniques which enables efficient design iterations in the development stage. In this study, we demonstrate a single-step fabrication of a 3D transparent microfluidic chip using two alternative techniques: a stereolithography-based desktop 3D printer and a two-step fabrication using an industrial 3D printer based on polyjet technology. This method, compared to conventional fabrication using relatively expensive materials and labor-intensive processes, presents a low-cost, rapid prototyping technique to print functional 3D microfluidic chips. We enhance the capabilities of 3D-printed microfluidic devices by coupling 3D cell encapsulation and spatial patterning within photocrosslinkable gelatin methacryloyl (GelMA). The platform presented here serves as a 3D culture environment for long-term cell culture and growth. Furthermore, we have demonstrated the ability to print complex 3D microfluidic channels to create predictable and controllable fluid flow regimes. Here, we demonstrate the novel use of 3D-printed microfluidic chips as controllable 3D cell culture environments, advancing the applicability of 3D printing to engineering physiological systems for future applications in bioengineering. PMID:27321481

  5. Remote 3D Medical Consultation

    NASA Astrophysics Data System (ADS)

    Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.

    Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.

  6. Speaking Volumes About 3-D

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.

  7. Finding and tracing human MSC in 3D microenvironments with the photoconvertible protein Dendra2

    NASA Astrophysics Data System (ADS)

    Caires, Hugo R.; Gomez-Lazaro, Maria; Oliveira, Carla M.; Gomes, David; Mateus, Denisa D.; Oliveira, Carla; Barrias, Cristina C.; Barbosa, Mário A.; Almeida, Catarina R.

    2015-05-01

    Mesenchymal Stem/Stromal Cells (MSC) are a promising cell type for cell-based therapies - from tissue regeneration to treatment of autoimmune diseases - due to their capacity to migrate to damaged tissues, to differentiate in different lineages and to their immunomodulatory and paracrine properties. Here, a simple and reliable imaging technique was developed to study MSC dynamical behavior in natural and bioengineered 3D matrices. Human MSC were transfected to express a fluorescent photoswitchable protein, Dendra2, which was used to highlight and follow the same group of cells for more than seven days, even if removed from the microscope to the incubator. This strategy provided reliable tracking in 3D microenvironments with different properties, including the hydrogels Matrigel and alginate as well as chitosan porous scaffolds. Comparison of cells mobility within matrices with tuned physicochemical properties revealed that MSC embedded in Matrigel migrated 64% more with 5.2 mg protein/mL than with 9.6 mg/mL and that MSC embedded in RGD-alginate migrated 51% faster with 1% polymer concentration than in 2% RGD-alginate. This platform thus provides a straightforward approach to characterize MSC dynamics in 3D and has applications in the field of stem cell biology and for the development of biomaterials for tissue regeneration.

  8. Evaluating scatterometry 3D capabilities for EUV

    NASA Astrophysics Data System (ADS)

    Li, Jie; Kritsun, Oleg; Dasari, Prasad; Volkman, Catherine; Wallow, Tom; Hu, Jiangtao

    2013-04-01

    Optical critical dimension (OCD) metrology using scatterometry has been demonstrated to be a viable solution for fast and non-destructive in-line process control and monitoring. As extreme ultraviolet lithography (EUVL) is more widely adopted to fabricate smaller and smaller patterns for electronic devices, scatterometry faces new challenges due to several reasons. For 14nm node and beyond, the feature size is nearly an order of magnitude smaller than the shortest wavelength used in scatterometry. In addition, thinner resist layer is used in EUVL compared with conventional lithography, which leads to reduced measurement sensitivity. Despite these difficulties, tolerance has reduced for smaller feature size. In this work we evaluate 3D capability of scatterometry for EUV process using spectroscopic ellipsometry (SE). Three types of structures, contact holes, tip-to-tip, and tip-to-edge, are studied to test CD and end-gap metrology capabilities. The wafer is processed with focus and exposure matrix. Good correlations to CD-SEM results are achieved and good dynamic precision is obtained for all the key parameters. In addition, the fit to process provides an independent method to evaluate data quality from different metrology tools such as OCD and CDSEM. We demonstrate 3D capabilities of scatterometry OCD metrology for EUVL using spectroscopic ellipsometry, which provides valuable in-line metrology for CD and end-gap control in electronic circuit fabrications.

  9. 3D-Printing for Analytical Ultracentrifugation.

    PubMed

    Desai, Abhiksha; Krynitsky, Jonathan; Pohida, Thomas J; Zhao, Huaying; Schuck, Peter

    2016-01-01

    Analytical ultracentrifugation (AUC) is a classical technique of physical biochemistry providing information on size, shape, and interactions of macromolecules from the analysis of their migration in centrifugal fields while free in solution. A key mechanical element in AUC is the centerpiece, a component of the sample cell assembly that is mounted between the optical windows to allow imaging and to seal the sample solution column against high vacuum while exposed to gravitational forces in excess of 300,000 g. For sedimentation velocity it needs to be precisely sector-shaped to allow unimpeded radial macromolecular migration. During the history of AUC a great variety of centerpiece designs have been developed for different types of experiments. Here, we report that centerpieces can now be readily fabricated by 3D printing at low cost, from a variety of materials, and with customized designs. The new centerpieces can exhibit sufficient mechanical stability to withstand the gravitational forces at the highest rotor speeds and be sufficiently precise for sedimentation equilibrium and sedimentation velocity experiments. Sedimentation velocity experiments with bovine serum albumin as a reference molecule in 3D printed centerpieces with standard double-sector design result in sedimentation boundaries virtually indistinguishable from those in commercial double-sector epoxy centerpieces, with sedimentation coefficients well within the range of published values. The statistical error of the measurement is slightly above that obtained with commercial epoxy, but still below 1%. Facilitated by modern open-source design and fabrication paradigms, we believe 3D printed centerpieces and AUC accessories can spawn a variety of improvements in AUC experimental design, efficiency and resource allocation. PMID:27525659

  10. 3D-Printing for Analytical Ultracentrifugation

    PubMed Central

    Desai, Abhiksha; Krynitsky, Jonathan; Pohida, Thomas J.; Zhao, Huaying

    2016-01-01

    Analytical ultracentrifugation (AUC) is a classical technique of physical biochemistry providing information on size, shape, and interactions of macromolecules from the analysis of their migration in centrifugal fields while free in solution. A key mechanical element in AUC is the centerpiece, a component of the sample cell assembly that is mounted between the optical windows to allow imaging and to seal the sample solution column against high vacuum while exposed to gravitational forces in excess of 300,000 g. For sedimentation velocity it needs to be precisely sector-shaped to allow unimpeded radial macromolecular migration. During the history of AUC a great variety of centerpiece designs have been developed for different types of experiments. Here, we report that centerpieces can now be readily fabricated by 3D printing at low cost, from a variety of materials, and with customized designs. The new centerpieces can exhibit sufficient mechanical stability to withstand the gravitational forces at the highest rotor speeds and be sufficiently precise for sedimentation equilibrium and sedimentation velocity experiments. Sedimentation velocity experiments with bovine serum albumin as a reference molecule in 3D printed centerpieces with standard double-sector design result in sedimentation boundaries virtually indistinguishable from those in commercial double-sector epoxy centerpieces, with sedimentation coefficients well within the range of published values. The statistical error of the measurement is slightly above that obtained with commercial epoxy, but still below 1%. Facilitated by modern open-source design and fabrication paradigms, we believe 3D printed centerpieces and AUC accessories can spawn a variety of improvements in AUC experimental design, efficiency and resource allocation. PMID:27525659

  11. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  12. 3D visualization of polymer nanostructure

    SciTech Connect

    Werner, James H

    2009-01-01

    Soft materials and structured polymers are extremely useful nanotechnology building blocks. Block copolymers, in particular, have served as 2D masks for nanolithography and 3D scaffolds for photonic crystals, nanoparticle fabrication, and solar cells. F or many of these applications, the precise 3 dimensional structure and the number and type of defects in the polymer is important for ultimate function. However, directly visualizing the 3D structure of a soft material from the nanometer to millimeter length scales is a significant technical challenge. Here, we propose to develop the instrumentation needed for direct 3D structure determination at near nanometer resolution throughout a nearly millimeter-cubed volume of a soft, potentially heterogeneous, material. This new capability will be a valuable research tool for LANL missions in chemistry, materials science, and nanoscience. Our approach to soft materials visualization builds upon exciting developments in super-resolution optical microscopy that have occurred over the past two years. To date, these new, truly revolutionary, imaging methods have been developed and almost exclusively used for biological applications. However, in addition to biological cells, these super-resolution imaging techniques hold extreme promise for direct visualization of many important nanostructured polymers and other heterogeneous chemical systems. Los Alamos has a unique opportunity to lead the development of these super-resolution imaging methods for problems of chemical rather than biological significance. While these optical methods are limited to systems transparent to visible wavelengths, we stress that many important functional chemicals such as polymers, glasses, sol-gels, aerogels, or colloidal assemblies meet this requirement, with specific examples including materials designed for optical communication, manipulation, or light-harvesting Our Research Goals are: (1) Develop the instrumentation necessary for imaging materials

  13. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  14. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2003-05-12

    This project is in its first full year after the combining of two previously funded projects: ''3D Code Development'' and ''Dynamic Material Properties''. The motivation behind this move was to emphasize and strengthen the ties between the experimental work and the computational model development in the materials area. The next year's activities will indicate the merging of the two efforts. The current activity is structured in two tasks. Task A, ''Simulations and Measurements'', combines all the material model development and associated numerical work with the materials-oriented experimental activities. Task B, ''ALE3D Development'', is a continuation of the non-materials related activities from the previous project.

  15. Three-dimensional printing-based electro-millifluidic devices for fabricating multi-compartment particles.

    PubMed

    Chen, Qiu Lan; Liu, Zhou; Shum, Ho Cheung

    2014-11-01

    In this work, we demonstrate the use of stereolithographic 3D printing to fabricate millifluidic devices, which are used to engineer particles with multiple compartments. As the 3D design is directly transferred to the actual prototype, this method accommodates 3D millimeter-scaled features that are difficult to achieve by either lithographic-based microfabrication or traditional macrofabrication techniques. We exploit this approach to produce millifluidic networks to deliver multiple fluidic components. By taking advantage of the laminar flow, the fluidic components can form liquid jets with distinct patterns, and each pattern has clear boundaries between the liquid phases. Afterwards, droplets with controlled size are fabricated by spraying the liquid jet in an electric field, and subsequently converted to particles after a solidification step. As a demonstration, we fabricate calcium alginate particles with structures of (1) slice-by-slice multiple lamellae, (2) concentric core-shells, and (3) petals surrounding the particle centers. Furthermore, distinct hybrid particles combining two or more of the above structures are also obtained. These compartmentalized particles impart spatially dependent functionalities and properties. To show their applicability, various ingredients, including fruit juices, drugs, and magnetic nanoparticles are encapsulated in the different compartments as proof-of-concepts for applications, including food, drug delivery, and bioassays. Our 3D printed electro-millifluidic approach represents a convenient and robust method to extend the range of structures of functional particles. PMID:25553189

  16. Three-dimensional printing-based electro-millifluidic devices for fabricating multi-compartment particles

    PubMed Central

    Chen, Qiu Lan; Liu, Zhou; Shum, Ho Cheung

    2014-01-01

    In this work, we demonstrate the use of stereolithographic 3D printing to fabricate millifluidic devices, which are used to engineer particles with multiple compartments. As the 3D design is directly transferred to the actual prototype, this method accommodates 3D millimeter-scaled features that are difficult to achieve by either lithographic-based microfabrication or traditional macrofabrication techniques. We exploit this approach to produce millifluidic networks to deliver multiple fluidic components. By taking advantage of the laminar flow, the fluidic components can form liquid jets with distinct patterns, and each pattern has clear boundaries between the liquid phases. Afterwards, droplets with controlled size are fabricated by spraying the liquid jet in an electric field, and subsequently converted to particles after a solidification step. As a demonstration, we fabricate calcium alginate particles with structures of (1) slice-by-slice multiple lamellae, (2) concentric core-shells, and (3) petals surrounding the particle centers. Furthermore, distinct hybrid particles combining two or more of the above structures are also obtained. These compartmentalized particles impart spatially dependent functionalities and properties. To show their applicability, various ingredients, including fruit juices, drugs, and magnetic nanoparticles are encapsulated in the different compartments as proof-of-concepts for applications, including food, drug delivery, and bioassays. Our 3D printed electro-millifluidic approach represents a convenient and robust method to extend the range of structures of functional particles. PMID:25553189

  17. Powder-based 3D printing for bone tissue engineering.

    PubMed

    Brunello, G; Sivolella, S; Meneghello, R; Ferroni, L; Gardin, C; Piattelli, A; Zavan, B; Bressan, E

    2016-01-01

    Bone tissue engineered 3-D constructs customized to patient-specific needs are emerging as attractive biomimetic scaffolds to enhance bone cell and tissue growth and differentiation. The article outlines the features of the most common additive manufacturing technologies (3D printing, stereolithography, fused deposition modeling, and selective laser sintering) used to fabricate bone tissue engineering scaffolds. It concentrates, in particular, on the current state of knowledge concerning powder-based 3D printing, including a description of the properties of powders and binder solutions, the critical phases of scaffold manufacturing, and its applications in bone tissue engineering. Clinical aspects and future applications are also discussed. PMID:27086202

  18. SNL3dFace

    Energy Science and Technology Software Center (ESTSC)

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial featuresmore » of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.« less

  19. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  20. SNL3dFace

    SciTech Connect

    Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.

  1. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  2. TACO3D. 3-D Finite Element Heat Transfer Code

    SciTech Connect

    Mason, W.E.

    1992-03-04

    TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.

  3. 3D Printing: 3D Printing of Shape Memory Polymers for Flexible Electronic Devices (Adv. Mater. 22/2016).

    PubMed

    Zarek, Matt; Layani, Michael; Cooperstein, Ido; Sachyani, Ela; Cohn, Daniel; Magdassi, Shlomo

    2016-06-01

    On page 4449, D. Cohn, S. Magdassi, and co-workers describe a general and facile method based on 3D printing of methacrylated macromonomers to fabricate shape-memory objects that can be used in flexible and responsive electrical circuits. Such responsive objects can be used in the fabrication of soft robotics, minimal invasive medical devices, sensors, and wearable electronics. The use of 3D printing overcomes the poor processing characteristics of thermosets and enables complex geometries that are not easily accessible by other techniques. PMID:27273436

  4. Glasses-free 3D display based on micro-nano-approach and system

    NASA Astrophysics Data System (ADS)

    Lou, Yimin; Ye, Yan; Shen, Su; Pu, Donglin; Chen, Linsen

    2014-11-01

    Micro-nano optics and digital dot matrix hologram (DDMH) technique has been combined to code and fabricate glassfree 3D image. Two kinds of true color 3D DDMH have been designed. One of the design releases the fabrication complexity and the other enlarges the view angle of 3D DDMH. Chromatic aberration has been corrected using rainbow hologram technique. A holographic printing system combined the interference and projection lithography technique has been demonstrated. Fresnel lens and large view angle 3D DDMH have been outputted, excellent color performance of 3D image has been realized.

  5. 3D printing of versatile reactionware for chemical synthesis.

    PubMed

    Kitson, Philip J; Glatzel, Stefan; Chen, Wei; Lin, Chang-Gen; Song, Yu-Fei; Cronin, Leroy

    2016-05-01

    In recent decades, 3D printing (also known as additive manufacturing) techniques have moved beyond their traditional applications in the fields of industrial manufacturing and prototyping to increasingly find roles in scientific research contexts, such as synthetic chemistry. We present a general approach for the production of bespoke chemical reactors, termed reactionware, using two different approaches to extrusion-based 3D printing. This protocol describes the printing of an inert polypropylene (PP) architecture with the concurrent printing of soft material catalyst composites, using two different 3D printer setups. The steps of the PROCEDURE describe the design and preparation of a 3D digital model of the desired reactionware device and the preparation of this model for use with fused deposition modeling (FDM) type 3D printers. The protocol then further describes the preparation of composite catalyst-silicone materials for incorporation into the 3D-printed device and the steps required to fabricate a reactionware device. This combined approach allows versatility in the design and use of reactionware based on the specific needs of the experimental user. To illustrate this, we present a detailed procedure for the production of one such reactionware device that will result in the production of a sealed reactor capable of effecting a multistep organic synthesis. Depending on the design time of the 3D model, and including time for curing and drying of materials, this procedure can be completed in ∼3 d. PMID:27077333

  6. Optimization of keratin/alginate scaffold using RSM and its characterization for tissue engineering.

    PubMed

    Gupta, Pratima; Nayak, Kush Kumar

    2016-04-01

    The scaffold for tissue engineering was fabricated from a binary blend of keratin/alginate. The concentration and ratio of keratin and alginate was optimized by response surface methodology in a scaffold. The structural compatibility between keratin and alginate was examined by X-ray diffractometer and Fourier transforms infrared spectroscopy. Apparent porosity of the scaffold was calculated by Archimedes principles and its observed value of was found 96.25 ± 0.04%. The pore size of the scaffold was observed in the range between 10 and 200 μm. Tensile strength (0.33 ± 0.26 MPa) and percent of elongation at break (23.33 ± 2.52%) are the reported mechanical strength of the scaffold. Positive antimicrobial activity and in vitro degradation further confirms the fabrication of a scaffold required for tissue engineering application. PMID:26691383

  7. Floatable, macroporous structured alginate sphere supporting iron nanoparticles used for emergent Cr(VI) spill treatment.

    PubMed

    Huang, Jian-Fei; Li, Yong-Tao; Wu, Jin-Hua; Cao, Piao-Yang; Liu, Yong-Lin; Jiang, Gang-Biao

    2016-08-01

    Treatment of hexavalent chromium (Cr(VI)) spill accident is a great challenge due to its high toxicity, sudden and extensiveness. In this study, we designed and fabricated a hierarchical, ordered and macroporous structured alginate sphere to support in-situ synthesized zero-valent iron nanoparticle (the alginate-nZVI sphere). Field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS) images showed well dispersion of nZVI on the composite. This alginate-nZVI sphere exhibited good separability in effective removal of Cr(VI). The result from Cr(VI) removal experiment demonstrated a Cr(VI) removal efficiency of 98.2% at equilibrium time, which can be ascribed to the well dispersion of the nZVI. In addition, the alginate-nZVI sphere was effective in Cr(VI) removal in a wide range of pH from 3.0 to 11.0, by the merit of alginate substrate. Hence, the alginate-nZVI sphere might be a promising agent for an emergent Cr(VI) spill treatment by enhancing the dispersion, stabilization and separation properties of nZVI. PMID:27112857

  8. 3-D Relativistic MHD Simulations

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Frank, J.; Koide, S.; Sakai, J.-I.; Christodoulou, D. M.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W = 4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure.

  9. Forensic 3D Scene Reconstruction

    SciTech Connect

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  10. Forensic 3D scene reconstruction

    NASA Astrophysics Data System (ADS)

    Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.

    2000-05-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  11. 360-degree 3D profilometry

    NASA Astrophysics Data System (ADS)

    Song, Yuanhe; Zhao, Hong; Chen, Wenyi; Tan, Yushan

    1997-12-01

    A new method of 360 degree turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper. A sine light field is applied in the projected light stripe, meanwhile phase shifting technique is used to calculate phases of the light slit. Thereafter wrapped phase distribution of the slit is formed and the unwrapping process is made by means of the height information based on the light sectioning method. Therefore phase measuring results with better precision can be obtained. At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights. The principles of this method are discussed in detail and experimental results are shown in this paper.

  12. 3D Printable Graphene Composite.

    PubMed

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  13. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  14. 3D light scanning macrography.

    PubMed

    Huber, D; Keller, M; Robert, D

    2001-08-01

    The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078

  15. 3D-graphite structure

    SciTech Connect

    Belenkov, E. A. Ali-Pasha, V. A.

    2011-01-15

    The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes {alpha}{sub 1,1}, {alpha}{sub 1,3}, {alpha}{sub 1,5}, {alpha}{sub 2,1}, {alpha}{sub 2,3}, {alpha}{sub 3,1}, {beta}{sub 1,2}, {beta}{sub 1,4}, {beta}{sub 1,6}, {beta}{sub 2,1}, and {beta}{sub 3,2} consist of sp{sup 2}-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.

  16. Developing multi-cellular tumor spheroid model (MCTS) in the chitosan/collagen/alginate (CCA) fibrous scaffold for anticancer drug screening.

    PubMed

    Wang, Jian-Zheng; Zhu, Yu-Xia; Ma, Hui-Chao; Chen, Si-Nan; Chao, Ji-Ye; Ruan, Wen-Ding; Wang, Duo; Du, Feng-Guang; Meng, Yue-Zhong

    2016-05-01

    In this work, a 3D MCTS-CCA system was constructed by culturing multi-cellular tumor spheroid (MCTS) in the chitosan/collagen/alginate (CCA) fibrous scaffold for anticancer drug screening. The CCA scaffolds were fabricated by spray-spinning. The interactions between the components of the spray-spun fibers were evidenced by methods of Coomassie Blue stain, X-ray diffraction (XRD) and Fourier transform-infrared spectroscopy (FTIR). Co-culture indicated that MCF-7 cells showed a spatial growth pattern of multi-cellular tumor spheroid (MCTS) in the CCA fibrous scaffold with increased proliferation rate and drug-resistance to MMC, ADM and 5-Aza comparing with the 2D culture cells. Significant increases of total viable cells were found in 3D MCTS groups after drug administration by method of apoptotic analysis. Glucose-lactate analysis indicated that the metabolism of MCTS in CCA scaffold was closer to the tumor issue in vivo than the monolayer cells. In addition, MCTS showed the characteristic of epithelial mesenchymal transition (EMT) which is subverted by carcinoma cells to facilitate metastatic spread. These results demonstrated that MCTS in CCA scaffold possessed a more conservative phenotype of tumor than monolayer cells, and anticancer drug screening in 3D MCTS-CCA system might be superior to the 2D culture system. PMID:26952417

  17. [Real time 3D echocardiography].

    PubMed

    Bauer, F; Shiota, T; Thomas, J D

    2001-07-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630

  18. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  19. 3D Printing of Conductive Complex Structures with In Situ Generation of Silver Nanoparticles.

    PubMed

    Fantino, Erika; Chiappone, Annalisa; Roppolo, Ignazio; Manfredi, Diego; Bongiovanni, Roberta; Pirri, Candido Fabrizio; Calignano, Flaviana

    2016-05-01

    Coupling the photoreduction of a metal precursor with 3D-printing technology is shown to allow the fabrication of conductive 3D hybrid structures consisting of metal nanoparticles and organic polymers shaped in complex multilayered architectures. 3D conductive structures are fabricated incorporating silver nitrate into a photocurable oligomer in the presence of suitable photoinitiators and exposing them to a digital light system. PMID:26992060

  20. Transplantation of Neural Stem Cells Cultured in Alginate Scaffold for Spinal Cord Injury in Rats

    PubMed Central

    Sharafkhah, Ali; Koohi-Hosseinabadi, Omid; Semsar-Kazerooni, Maryam

    2016-01-01

    Study Design This study investigated the effects of transplantation of alginate encapsulated neural stem cells (NSCs) on spinal cord injury in Sprague-Dawley male rats. The neurological functions were assessed for 6 weeks after transplantation along with a histological study and measurement of caspase-3 levels. Purpose The aim of this study was to discover whether NSCs cultured in alginate transplantation improve recovery from spinal cord injury. Overview of Literature Spinal cord injury is one of the leading causes of disability and it has no effective treatment. Spinal cord injury can also cause sensory impairment. With an impetus on using stem cells therapy in various central nervous system settings, there is an interest in using stem cells for addressing spinal cord injury. Neural stem cell is one type of stem cells that is able to differentiate to all three neural lineages and it shows promise in spinal injury treatment. Furthermore, a number of studies have shown that culturing NSCs in three-dimensional (3D) scaffolds like alginate could enhance neural differentiation. Methods The NSCs were isolated from 14-day-old rat embryos. The isolated NSCs were cultured in growth media containing basic fibroblast growth factor and endothelial growth factor. The cells were characterized by differentiating to three neural lineages and they were cultured in an alginate scaffold. After 7 days the cells were encapsulated and transplanted in a rat model of spinal cord injury. Results Our data showed that culturing in an alginate 3D scaffold and transplantation of the NSCs could improve neurological outcome in a rat model of spinal cord injury. The inflammation scores and lesion sizes and also the activity of caspase-3 (for apoptosis evaluation) were less in encapsulated neural stem cell transplantation cases. Conclusions Transplantation of NSCs that were cultured in an alginate scaffold led to a better clinical and histological outcome for recovery from spinal cord injury in

  1. 3D Microfabrication Using Emulsion Mask Grayscale Photolithography Technique

    NASA Astrophysics Data System (ADS)

    Lee, Tze Pin; Mohamed, Khairudin

    2016-02-01

    Recently, the rapid development of technology such as biochips, microfluidic, micro-optical devices and micro-electromechanical-systems (MEMS) demands the capability to create complex design of three-dimensional (3D) microstructures. In order to create 3D microstructures, the traditional photolithography process often requires multiple photomasks to form 3D pattern from several stacked photoresist layers. This fabrication method is extremely time consuming, low throughput, costly and complicated to conduct for high volume manufacturing scale. On the other hand, next generation lithography such as electron beam lithography (EBL), focused ion beam lithography (FIB) and extreme ultraviolet lithography (EUV) are however too costly and the machines require expertise to setup. Therefore, the purpose of this study is to develop a simplified method in producing 3D microstructures using single grayscale emulsion mask technique. By using this grayscale fabrication method, microstructures of thickness as high as 500μm and as low as 20μm are obtained in a single photolithography exposure. Finally, the fabrication of 3D microfluidic channel has been demonstrated by using this grayscale photolithographic technique.

  2. GPU-Accelerated Denoising in 3D (GD3D)

    Energy Science and Technology Software Center (ESTSC)

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer themore » second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.« less

  3. Mechanically reinforced cell-laden scaffolds formed using alginate-based bioink printed onto the surface of a PCL/alginate mesh structure for regeneration of hard tissue.

    PubMed

    Kim, Yong Bok; Lee, Hyeongjin; Yang, Gi-Hoon; Choi, Chang Hyun; Lee, DaeWeon; Hwang, Heon; Jung, Won-Kyo; Yoon, Hyeon; Kim, Geun Hyung

    2016-01-01

    Cell-printing technology has provided a new paradigm for biofabrication, with potential to overcome several shortcomings of conventional scaffold-based tissue regeneration strategies via controlled delivery of various cell types in well-defined target regions. Here we describe a cell-printing method to obtain mechanically reinforced multi-layered cell-embedded scaffolds, formed of micron-scale poly(ε-caprolactone) (PCL)/alginate struts coated with alginate-based bioink. To compare the physical and cellular activities, we used a scaffold composed of pure alginate (without cells) coated PCL/alginate struts as a control. We systematically varied the ratio of alginate cross-linking agent, and determined the optimal cell-coating conditions to form the PCL/alginate struts. Following fabrication of the cell (MG63)-laden PCL/alginate scaffold, the bioactivity was evaluated in vitro. The laden cells exhibited a substantially more developed cytoskeleton compared with those on a control scaffold consisting of the same material composition. Based on these results, the printed cells exhibited a significantly more homogenous distribution within the scaffold compared with the control. Cell proliferation was determined via MTT assays at 1, 3, 7, and 14 days of culture, and the proliferation of the cell-printed scaffold was substantially in excess (∼2.4-fold) of that on the control. Furthermore, the osteogenic activity such as ALP was measured, and the cell-laden scaffold exhibited significantly greater activity (∼3.2-fold) compared with the control scaffold. PMID:26409783

  4. Process for 3D chip stacking

    DOEpatents

    Malba, Vincent

    1998-01-01

    A manufacturable process for fabricating electrical interconnects which extend from a top surface of an integrated circuit chip to a sidewall of the chip using laser pantography to pattern three dimensional interconnects. The electrical interconnects may be of an L-connect or L-shaped type. The process implements three dimensional (3D) stacking by moving the conventional bond or interface pads on a chip to the sidewall of the chip. Implementation of the process includes: 1) holding individual chips for batch processing, 2) depositing a dielectric passivation layer on the top and sidewalls of the chips, 3) opening vias in the dielectric, 4) forming the interconnects by laser pantography, and 5) removing the chips from the holding means. The process enables low cost manufacturing of chips with bond pads on the sidewalls, which enables stacking for increased performance, reduced space, and higher functional per unit volume.

  5. Process for 3D chip stacking

    DOEpatents

    Malba, V.

    1998-11-10

    A manufacturable process for fabricating electrical interconnects which extend from a top surface of an integrated circuit chip to a sidewall of the chip using laser pantography to pattern three dimensional interconnects. The electrical interconnects may be of an L-connect or L-shaped type. The process implements three dimensional (3D) stacking by moving the conventional bond or interface pads on a chip to the sidewall of the chip. Implementation of the process includes: (1) holding individual chips for batch processing, (2) depositing a dielectric passivation layer on the top and sidewalls of the chips, (3) opening vias in the dielectric, (4) forming the interconnects by laser pantography, and (5) removing the chips from the holding means. The process enables low cost manufacturing of chips with bond pads on the sidewalls, which enables stacking for increased performance, reduced space, and higher functional per unit volume. 3 figs.

  6. 3D-Printed Microfluidic Automation

    PubMed Central

    Au, Anthony K.; Bhattacharjee, Nirveek; Horowitz, Lisa F.; Chang, Tim C.; Folch, Albert

    2015-01-01

    Microfluidic automation – the automated routing, dispensing, mixing, and/or separation of fluids through microchannels – generally remains a slowly-spreading technology because device fabrication requires sophisticated facilities and the technology’s use demands expert operators. Integrating microfluidic automation in devices has involved specialized multi-layering and bonding approaches. Stereolithography is an assembly-free, 3D-printing technique that is emerging as an efficient alternative for rapid prototyping of biomedical devices. Here we describe fluidic valves and pumps that can be stereolithographically printed in optically-clear, biocompatible plastic and integrated within microfluidic devices at low cost. User-friendly fluid automation devices can be printed and used by non-engineers as replacement for costly robotic pipettors or tedious manual pipetting. Engineers can manipulate the designs as digital modules into new devices of expanded functionality. Printing these devices only requires the digital file and electronic access to a printer. PMID:25738695

  7. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  8. Arbitrary and Parallel Nanofabrication of 3D Metal Structures with Polymer Brush Resists.

    PubMed

    Chen, Chaojian; Xie, Zhuang; Wei, Xiaoling; Zheng, Zijian

    2015-12-01

    3D polymer brushes are reported for the first time as ideal resists for the alignment-free nanofabrication of complex 3D metal structures with sub-100 nm lateral resolution and sub-10 nm vertical resolution. Since 3D polymer brushes can be serially fabricated in parallel, this method is effective to generate arbitrary 3D metal structures over a large area at a high throughput. PMID:26439441

  9. 3D-printed mechanochromic materials.

    PubMed

    Peterson, Gregory I; Larsen, Michael B; Ganter, Mark A; Storti, Duane W; Boydston, Andrew J

    2015-01-14

    We describe the preparation and characterization of photo- and mechanochromic 3D-printed structures using a commercial fused filament fabrication printer. Three spiropyran-containing poly(ε-caprolactone) (PCL) polymers were each filamentized and used to print single- and multicomponent tensile testing specimens that would be difficult, if not impossible, to prepare using traditional manufacturing techniques. It was determined that the filament production and printing process did not degrade the spiropyran units or polymer chains and that the mechanical properties of the specimens prepared with the custom filament were in good agreement with those from commercial PCL filament. In addition to printing photochromic and dual photo- and mechanochromic PCL materials, we also prepare PCL containing a spiropyran unit that is selectively activated by mechanical impetus. Multicomponent specimens containing two different responsive spiropyrans enabled selective activation of different regions within the specimen depending on the stimulus applied to the material. By taking advantage of the unique capabilities of 3D printing, we also demonstrate rapid modification of a prototype force sensor that enables the assessment of peak load by simple visual assessment of mechanochromism. PMID:25478746

  10. Wax-bonding 3D microfluidic chips.

    PubMed

    Gong, Xiuqing; Yi, Xin; Xiao, Kang; Li, Shunbo; Kodzius, Rimantas; Qin, Jianhua; Wen, Weijia

    2010-10-01

    We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes. The hot-melt adhesive wax can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP). Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein (GFP) recombinant Escherichia coli (E. coli) bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration. PMID:20689865

  11. Development of a 3D printer using scanning projection stereolithography

    PubMed Central

    Lee, Michael P.; Cooper, Geoffrey J. T.; Hinkley, Trevor; Gibson, Graham M.; Padgett, Miles J.; Cronin, Leroy

    2015-01-01

    We have developed a system for the rapid fabrication of low cost 3D devices and systems in the laboratory with micro-scale features yet cm-scale objects. Our system is inspired by maskless lithography, where a digital micromirror device (DMD) is used to project patterns with resolution up to 10 µm onto a layer of photoresist. Large area objects can be fabricated by stitching projected images over a 5cm2 area. The addition of a z-stage allows multiple layers to be stacked to create 3D objects, removing the need for any developing or etching steps but at the same time leading to true 3D devices which are robust, configurable and scalable. We demonstrate the applications of the system by printing a range of micro-scale objects as well as a fully functioning microfluidic droplet device and test its integrity by pumping dye through the channels. PMID:25906401

  12. 3D-Printed Biodegradable Polymeric Vascular Grafts.

    PubMed

    Melchiorri, Anthony J; Hibino, Narutoshi; Best, C A; Yi, T; Lee, Y U; Kraynak, C A; Kimerer, Lucas K; Krieger, A; Kim, P; Breuer, Christopher K; Fisher, John P

    2016-02-01

    Congenital heart defect interventions may benefit from the fabrication of patient-specific vascular grafts because of the wide array of anatomies present in children with cardiovascular defects. 3D printing is used to establish a platform for the production of custom vascular grafts, which are biodegradable, mechanically compatible with vascular tissues, and support neotissue formation and growth. PMID:26627057

  13. Bioactive polymeric-ceramic hybrid 3D scaffold for application in bone tissue regeneration.

    PubMed

    Torres, A L; Gaspar, V M; Serra, I R; Diogo, G S; Fradique, R; Silva, A P; Correia, I J

    2013-10-01

    The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric-bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. PMID:23910366

  14. Imaging Contrast Effects in Alginate Microbeads

    NASA Astrophysics Data System (ADS)

    Shapley, Nina; Hester-Reilly, Holly

    2007-03-01

    We have investigated the use of alginate gel microbeads as contrast agents for the study of suspension flows in complex geometries using nuclear magnetic resonance (NMR) imaging. These deformable particles can provide imaging contrast to rigid polymer particles in a bimodal suspension (two particle sizes). Microbeads were formed of crosslinked alginate gel, with or without trapped oil droplets. Crosslinking of the aqueous sodium alginate solution or the continuous phase of an oil-in-water emulsion occurred rapidly at gentle processing conditions. The alginate microbeads exhibit both spin-spin relaxation time (T2) contrast and diffusion contrast relative to both the suspending fluid and rigid polystyrene particles. Large alginate emulsion microbeads flowing in the abrupt, axisymmetric expansion geometry can be clearly distinguished from the suspending fluid and from rigid polymer particles in both spin-echo and diffusion weighted imaging. The alginate microbeads, particularly those containing trapped emulsion droplets, offer potential as a positive contrast agent in multiple NMR imaging applications.

  15. 3D Printing technologies for drug delivery: a review.

    PubMed

    Prasad, Leena Kumari; Smyth, Hugh

    2016-07-01

    With the FDA approval of the first 3D printed tablet, Spritam®, there is now precedence set for the utilization of 3D printing for the preparation of drug delivery systems. The capabilities for dispensing low volumes with accuracy, precise spatial control and layer-by-layer assembly allow for the preparation of complex compositions and geometries. The high degree of flexibility and control with 3D printing enables the preparation of dosage forms with multiple active pharmaceutical ingredients with complex and tailored release profiles. A unique opportunity for this technology for the preparation of personalized doses to address individual patient needs. This review will highlight the 3D printing technologies being utilized for the fabrication of drug delivery systems, as well as the formulation and processing parameters for consideration. This article will also summarize the range of dosage forms that have been prepared using these technologies, specifically over the last 10 years. PMID:26625986

  16. Bukliball and Beyond: 3-D Soft Auxetic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shim, Jongmin; Babaee, Sahab; Weaver, James C.; Patel, Nikita; Chen, Elizabeth R.; Bertoldi, Katia

    2013-03-01

    We present a new class of 3-D soft metamaterials whose microstructure can be dramatically changed in response to mechanical loading. Patterned spherical shells, the Buckliballs (PNAS 109(16):5978) which undergo undergoing a buckling-induced structural transformation under pressure, are employed as building blocks, and are assembled to construct 3-D super-structures. We present procedures to guide the selection of both the building blocks and their arrangement, and design materials with tunable 3-D auxetic behavior that exploit buckling as the actuation mechanism. The validity of the proposed material design is demonstrated through both experiments and finite element simulations. This pattern transformation induced by a mechanical instability opens the possibility for fabrication of 3-D auxetic materials/structures over a wide range of length scales.

  17. Developing novel 3D antennas using advanced additive manufacturing technology

    NASA Astrophysics Data System (ADS)

    Mirzaee, Milad

    In today's world of wireless communication systems, antenna engineering is rapidly advancing as the wireless services continue to expand in support of emerging commercial applications. Antennas play a key role in the performance of advanced transceiver systems where they serve to convert electric power to electromagnetic waves and vice versa. Researchers have held significant interest in developing this crucial component for wireless communication systems by employing a variety of design techniques. In the past few years, demands for electrically small antennas continues to increase, particularly among portable and mobile wireless devices, medical electronics and aerospace systems. This trend toward smaller electronic devices makes the three dimensional (3D) antennas very appealing, since they can be designed in a way to use every available space inside the devise. Additive Manufacturing (AM) method could help to find great solutions for the antennas design for next generation of wireless communication systems. In this thesis, the design and fabrication of 3D printed antennas using AM technology is studied. To demonstrate this application of AM, different types of antennas structures have been designed and fabricated using various manufacturing processes. This thesis studies, for the first time, embedded conductive 3D printed antennas using PolyLactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) for substrate parts and high temperature carbon paste for conductive parts which can be a good candidate to overcome the limitations of direct printing on 3D surfaces that is the most popular method to fabricate conductive parts of the antennas. This thesis also studies, for the first time, the fabrication of antennas with 3D printed conductive parts which can contribute to the new generation of 3D printed antennas.

  18. Interactive 3D Mars Visualization

    NASA Technical Reports Server (NTRS)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  19. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  20. Making Inexpensive 3-D Models

    NASA Astrophysics Data System (ADS)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  1. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  2. Vacant Lander in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D image captured by the Mars Exploration Rover Opportunity's rear hazard-identification camera shows the now-empty lander that carried the rover 283 million miles to Meridiani Planum, Mars. Engineers received confirmation that Opportunity's six wheels successfully rolled off the lander and onto martian soil at 3:01 a.m. PST, January 31, 2004, on the seventh martian day, or sol, of the mission. The rover is approximately 1 meter (3 feet) in front of the lander, facing north.

  3. [Alginates in therapy for gastroesophageal reflux disease].

    PubMed

    Avdeev, V G

    2015-01-01

    This article presents evidence of the prevalence of gastroesophageal reflux disease (GERD) and highlights its main treatment options. Among its medications, particular emphasis is laid on alginates and their main mechanisms of action are described. There is information on the efficacy of alginates, including the alginate-antacid Gaviscon Double Action, in treating GERD. Recommendations for how to administer these drugs are given. PMID:26155630

  4. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  5. Embedding objects during 3D printing to add new functionalities.

    PubMed

    Yuen, Po Ki

    2016-07-01

    A novel method for integrating and embedding objects to add new functionalities during 3D printing based on fused deposition modeling (FDM) (also known as fused filament fabrication or molten polymer deposition) is presented. Unlike typical 3D printing, FDM-based 3D printing could allow objects to be integrated and embedded during 3D printing and the FDM-based 3D printed devices do not typically require any post-processing and finishing. Thus, various fluidic devices with integrated glass cover slips or polystyrene films with and without an embedded porous membrane, and optical devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber were 3D printed to demonstrate the versatility of the FDM-based 3D printing and embedding method. Fluid perfusion flow experiments with a blue colored food dye solution were used to visually confirm fluid flow and/or fluid perfusion through the embedded porous membrane in the 3D printed fluidic devices. Similar to typical 3D printed devices, FDM-based 3D printed devices are translucent at best unless post-polishing is performed and optical transparency is highly desirable in any fluidic devices; integrated glass cover slips or polystyrene films would provide a perfect optical transparent window for observation and visualization. In addition, they also provide a compatible flat smooth surface for biological or biomolecular applications. The 3D printed fluidic devices with an embedded porous membrane are applicable to biological or chemical applications such as continuous perfusion cell culture or biocatalytic synthesis but without the need for any post-device assembly and finishing. The 3D printed devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber would have applications in display, illumination, or optical applications. Furthermore, the FDM-based 3D printing and embedding method could also be utilized to print casting molds with an integrated glass bottom for polydimethylsiloxane (PDMS) device replication

  6. Positional Awareness Map 3D (PAM3D)

    NASA Technical Reports Server (NTRS)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  7. Magneto-responsive alginate capsules

    NASA Astrophysics Data System (ADS)

    Degen, Patrick; Zwar, Elena; Schulz, Imke; Rehage, Heinz

    2015-05-01

    Upon incorporation of magnetic nanoparticles (mNPs) into gels, composite materials called ferrogels are obtained. These magneto-responsive systems have a wide range of potential applications including switches and sensors as well as drug delivery systems. In this article, we focus on the properties of calcium alginate capsules, which are widely used as carrier systems in medicine and technology. We studied the incorporation of different kinds of mNPs in matrix capsules and in the core and the shell of hollow particles. We found out that not all particle-alginate or particle-CaCl2 solution combinations were suitable for a successful capsule preparation on grounds of a destabilization of the nanoparticles or the polymer. For those systems allowing the preparation of switchable beads or capsules, we systematically studied the size and microscopic structure of the capsules, their magnetic behavior and mechanical resistance.

  8. Fabrication of Collagen Gel Hollow Fibers by Covalent Cross-Linking for Construction of Bioengineering Renal Tubules.

    PubMed

    Shen, Chong; Zhang, Guoliang; Wang, Qichen; Meng, Qin

    2015-09-01

    Collagen, the most used natural biomacromolecule, has been extensively utilized to make scaffolds for cell cultures in tissue engineering, but has never been fabricated into the configuration of a hollow fiber (HF) for cell culture due to its poor mechanical properties. In this study, renal tubular cell-laden collagen hollow fiber (Col HF) was fabricated by dissolving sacrificial Ca-alginate cores from collagen shells strengthened by carbodiimide cross-linking. The inner/outer diameters of the Col HF were precisely controlled by the flow rates of core alginate/shell collagen solution in the microfluidic device. As found, the renal tubular cells self-assembled into renal tubules with diameters of 50-200 μm post to the culture in Col HF for 10 days. According to the 3D reconstructed confocal images or HE staining, the renal cells appeared as a tight tubular monolayer on the Col HF inner surface, sustaining more 3D cell morphology than the cell layer on the 2D flat collagen gel surface. Moreover, compared with the cultures in either a Transwell or polymer HF membrane, the renal tubules in Col HF exhibited at least 1-fold higher activity on brush border enzymes of alkaline phosphatase and γ-glutamyltransferase, consistent with their gene expressions. The enhancement occurred similarly on multidrug resistance protein 2 and glucose uptake. Such bioengineered renal tubules in Col HF will present great potential as alternatives to synthetic HF in both clinical use and pharmaceutical investigation. PMID:26280545

  9. 3D Printable Graphene Composite

    NASA Astrophysics Data System (ADS)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  10. 3D acoustic atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Rogers, Kevin; Finn, Anthony

    2014-10-01

    This paper presents a method for tomographically reconstructing spatially varying 3D atmospheric temperature profiles and wind velocity fields based. Measurements of the acoustic signature measured onboard a small Unmanned Aerial Vehicle (UAV) are compared to ground-based observations of the same signals. The frequency-shifted signal variations are then used to estimate the acoustic propagation delay between the UAV and the ground microphones, which are also affected by atmospheric temperature and wind speed vectors along each sound ray path. The wind and temperature profiles are modelled as the weighted sum of Radial Basis Functions (RBFs), which also allow local meteorological measurements made at the UAV and ground receivers to supplement any acoustic observations. Tomography is used to provide a full 3D reconstruction/visualisation of the observed atmosphere. The technique offers observational mobility under direct user control and the capacity to monitor hazardous atmospheric environments, otherwise not justifiable on the basis of cost or risk. This paper summarises the tomographic technique and reports on the results of simulations and initial field trials. The technique has practical applications for atmospheric research, sound propagation studies, boundary layer meteorology, air pollution measurements, analysis of wind shear, and wind farm surveys.

  11. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  12. 3-D Relativistic MHD Simulations

    NASA Astrophysics Data System (ADS)

    Nishikaw, K.-I.; Frank, J.; Christodoulou, D. M.; Koide, S.; Sakai, J.-I.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W=4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure. We also simulate jets with the more realistic initial conditions for injecting jets for helical mangetic field, perturbed density, velocity, and internal energy, which are supposed to be caused in the process of jet generation. Three possible explanations for the observed variability are (i) tidal disruption of a star falling into the black hole, (ii) instabilities in the relativistic accretion disk, and (iii) jet-related PRocesses. New results will be reported at the meeting.

  13. 3D printed bionic ears.

    PubMed

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  14. 3D Printable Graphene Composite

    PubMed Central

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  15. 3D medical thermography device

    NASA Astrophysics Data System (ADS)

    Moghadam, Peyman

    2015-05-01

    In this paper, a novel handheld 3D medical thermography system is introduced. The proposed system consists of a thermal-infrared camera, a color camera and a depth camera rigidly attached in close proximity and mounted on an ergonomic handle. As a practitioner holding the device smoothly moves it around the human body parts, the proposed system generates and builds up a precise 3D thermogram model by incorporating information from each new measurement in real-time. The data is acquired in motion, thus it provides multiple points of view. When processed, these multiple points of view are adaptively combined by taking into account the reliability of each individual measurement which can vary due to a variety of factors such as angle of incidence, distance between the device and the subject and environmental sensor data or other factors influencing a confidence of the thermal-infrared data when captured. Finally, several case studies are presented to support the usability and performance of the proposed system.

  16. 3D Ion Temperature Reconstruction

    NASA Astrophysics Data System (ADS)

    Tanabe, Hiroshi; You, Setthivoine; Balandin, Alexander; Inomoto, Michiaki; Ono, Yasushi

    2009-11-01

    The TS-4 experiment at the University of Tokyo collides two spheromaks to form a single high-beta compact toroid. Magnetic reconnection during the merging process heats and accelerates the plasma in toroidal and poloidal directions. The reconnection region has a complex 3D topology determined by the pitch of the spheromak magnetic fields at the merging plane. A pair of multichord passive spectroscopic diagnostics have been established to measure the ion temperature and velocity in the reconnection volume. One setup measures spectral lines across a poloidal plane, retrieving velocity and temperature from Abel inversion. The other, novel setup records spectral lines across another section of the plasma and reconstructs velocity and temperature from 3D vector and 2D scalar tomography techniques. The magnetic field linking both measurement planes is determined from in situ magnetic probe arrays. The ion temperature is then estimated within the volume between the two measurement planes and at the reconnection region. The measurement is followed over several repeatable discharges to follow the heating and acceleration process during the merging reconnection.

  17. A honeycomb composite of mollusca shell matrix and calcium alginate.

    PubMed

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering. PMID:26700239

  18. LOTT RANCH 3D PROJECT

    SciTech Connect

    Larry Lawrence; Bruce Miller

    2004-09-01

    The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data

  19. Magnetic field-responsive release of transforming growth factor beta 1 from heparin-modified alginate ferrogels.

    PubMed

    Kim, Hwi; Park, Honghyun; Lee, Jae Won; Lee, Kuen Yong

    2016-10-20

    Stimuli-responsive polymeric systems have been widely used for various drug delivery and tissue engineering applications. Magnetic stimulation can be also exploited to regulate the release of pharmaceutical drugs, growth factors, and cells from hydrogels in a controlled manner, on-demand. In the present study, alginate ferrogels containing iron oxide nanoparticles were fabricated via ionic cross-linking, and their various characteristics were investigated. The deformation of the ferrogels was dependent on the polymer concentration, calcium concentration, iron oxide concentration, and strength of magnetic field. To modulate the release of transforming growth factor beta 1 (TGF-β1) under magnetic stimulation, alginate was chemically modified with heparin, as TGF-β1 has a heparin-binding domain. Alginate was first modified with ethylenediamine, and heparin was then conjugated to the ethylenediamine-modified alginate via carbodiimide chemistry. Conjugation of heparin to alginate was confirmed by infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. Sustained release of TGF-β1 from alginate-g-heparin ferrogels was achieved, and application of a magnetic field to the ferrogels regulated TGF-β1 release, resultantly enhancing chondrogenic differentiation of ATDC5 cells, which were used as a model chondrogenic cell line. Alginate-based ferrogels that release drugs in a controlled manner may therefore be useful in many biomedical applications. PMID:27474590

  20. Alginate cryogel based glucose biosensor

    NASA Astrophysics Data System (ADS)

    Fatoni, Amin; Windy Dwiasi, Dian; Hermawan, Dadan

    2016-02-01

    Cryogel is macroporous structure provides a large surface area for biomolecule immobilization. In this work, an alginate cryogel based biosensor was developed to detect glucose. The cryogel was prepared using alginate cross-linked by calcium chloride under sub-zero temperature. This porous structure was growth in a 100 μL micropipette tip with a glucose oxidase enzyme entrapped inside the cryogel. The glucose detection was based on the colour change of redox indicator, potassium permanganate, by the hydrogen peroxide resulted from the conversion of glucose. The result showed a porous structure of alginate cryogel with pores diameter of 20-50 μm. The developed glucose biosensor was showed a linear response in the glucose detection from 1.0 to 5.0 mM with a regression of y = 0.01x+0.02 and R2 of 0.994. Furthermore, the glucose biosensor was showed a high operational stability up to 10 times of uninterrupted glucose detections.