Development and characterization of a novel drug nanocarrier for oral delivery, based on self-assembled β-casein micelles.

PubMed

Bachar, Michal; Mandelbaum, Amitai; Portnaya, Irina; Perlstein, Hadas; Even-Chen, Simcha; Barenholz, Yechezkel; Danino, Dganit

2012-06-10

β-casein is an amphiphilic protein that self-organizes into well-defined core-shell micelles. We developed these micelles as efficient nanocarriers for oral drug delivery. Our model drug is celecoxib, an anti-inflammatory hydrophobic drug utilized for treatment of rheumatoid arthritis and osteoarthritis, now also evaluated as a potent anticancer drug. This system is unique as it enables encapsulation loads >100-fold higher than other β-casein/drug formulations, and does not require additives as do other formulations that have high loadings. This is combined with the ability to lyophilize the formulation without a cryoprotectant, long-term physical and chemical stability of the resulting powder, and fully reversible reconstitution of the structures by rehydration. The dry dosage form, in which >95% of the drug is encapsulated, meets the daily dose. Cryo-TEM and DLS prove that drug encapsulation results in micelle swelling, and X-ray diffraction shows that the encapsulated drug is amorphous. Altogether, our novel dosage form is highly advantageous for oral administration. Copyright © 2012 Elsevier B.V. All rights reserved.

Surface acoustic wave actuated cell sorting (SAWACS).

PubMed

Franke, T; Braunmüller, S; Schmid, L; Wixforth, A; Weitz, D A

2010-03-21

We describe a novel microfluidic cell sorter which operates in continuous flow at high sorting rates. The device is based on a surface acoustic wave cell-sorting scheme and combines many advantages of fluorescence activated cell sorting (FACS) and fluorescence activated droplet sorting (FADS) in microfluidic channels. It is fully integrated on a PDMS device, and allows fast electronic control of cell diversion. We direct cells by acoustic streaming excited by a surface acoustic wave which deflects the fluid independently of the contrast in material properties of deflected objects and the continuous phase; thus the device underlying principle works without additional enhancement of the sorting by prior labelling of the cells with responsive markers such as magnetic or polarizable beads. Single cells are sorted directly from bulk media at rates as fast as several kHz without prior encapsulation into liquid droplet compartments as in traditional FACS. We have successfully directed HaCaT cells (human keratinocytes), fibroblasts from mice and MV3 melanoma cells. The low shear forces of this sorting method ensure that cells survive after sorting.

Surface functionalization of carbon nanotubes by direct encapsulation with varying dosages of amphiphilic block copolymers

NASA Astrophysics Data System (ADS)

Yao, Xueping; Li, Jie; Kong, Liang; Wang, Yong

2015-08-01

Encapsulation of carbon nanotubes (CNTs) by amphiphilic block copolymers is an efficient way to stabilize CNTs in solvents. However, the appropriate dosages of copolymers and the assembled structures are difficult to predict and control because of the insufficient understanding on the encapsulation process. We encapsulate multiwalled CNTs with polystyrene-block-poly (4-vinyl pyridine) (PS-b-P4VP) by directly mixing them in acetic acid under sonication. The copolymer forms a lamellar structure along the surface of CNTs with the PS blocks anchoring on the tube wall and the P4VP blocks exposed to the outside. The encapsulated CNTs achieve good dispersibility in polar solvents over long periods. To increase our understanding of the encapsulation process we investigate the assembled structures and stability of copolymer/CNTs mixtures with changing mass ratios. Stable dispersions are obtained at high mass ratios between the copolymer and CNTs, i.e. 2 or 3, with the presence of free spherical micelles. Transmission electron microscopy and thermal gravimetric analysis determine that the threshold for the complete coverage of CNTs by the copolymer occurs at the mass ratio of 1.5. The coated copolymer layer activates the surface of CNTs, enabling further functionalization of CNTs. For instance, atomic layer deposition of TiO2 produces conformal thin layers on the encapsulated CNTs while isolated TiO2 bumps are produced on the pristine, inert CNTs.

Design of interior-functionalized fully acetylated dendrimers for anticancer drug delivery.

PubMed

Hu, Jingjing; Su, Yunzhang; Zhang, Hongfeng; Xu, Tongwen; Cheng, Yiyun

2011-12-01

In this study, dendrimers was synthesized by introducing functional groups into the interior pockets of fully acetylated dendrimers. NMR techniques including COSY and 2D-NOESY revealed the molecular structures of the synthesized dendrimers and the encapsulation of guest molecule such as methotrexate within their interior pockets. The synthesized polymeric nanocarriers showed much lower cytotoxicity on two cell lines than cationic dendrimers, and exhibited better performance than fully acetylated dendrimers in the sustained release of methotrexate. The results provided a new strategy in the design of non-toxic dendrimers with high performance in the delivery of anti-cancer drugs for clinical applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

The results for Task 3 of the Low Cost Solar Array Project are presented. Task 3 is directed toward the development of a cost effective encapsulating system for photovoltaic modules using silicon based materials. The technical approach of the contract effort is divided into four special tasks: (1) technology review; (2) generation of concepts for screening and processing silicon encapsulation systems; (3) assessment of encapsulation concepts; and (4) evaluation of encapsulation concepts. The candidate silicon materials are reviewed. The silicon and modified silicon resins were chosen on the basis of similarity to materials with known weatherability, cost, initial tangential modulus, accelerated dirt pick-up test results and the ratio of the content of organic phenyl substitution of methyl substitution on the backbone of the silicon resin.

Amperometric glucose biosensor based on layer-by-layer films of microperoxidase-11 and liposome-encapsulated glucose oxidase.

PubMed

Graça, J S; de Oliveira, R F; de Moraes, M L; Ferreira, M

2014-04-01

An important step in several bioanalytical applications is the immobilization of biomolecules. Accordingly, this procedure must be carefully chosen to preserve their biological structure and fully explore their properties. For this purpose, we combined the versatility of the layer-by-layer (LbL) method for the immobilization of biomolecules with the protective behavior of liposome-encapsulated systems to fabricate a novel amperometric glucose biosensor. To obtain the biosensing unit, an LbL film of the H2O2 catalyst polypeptide microperoxidase-11 (MP-11) was assembled onto an indium-tin oxide (ITO) electrode followed by the deposition of a liposome-encapsulated glucose oxidase (GOx) layer. The biosensor response toward glucose detection showed a sensitivity of 0.91±0.09 (μA/cm2)/mM and a limit of detection (LOD) of 8.6±1.1 μM, demonstrating an improved performance compared to similar biosensors with a single phospholipid-liposome or even containing a non-encapsulated GOx layer. Finally, glucose detection was also performed in a zero-lactose milk sample to demonstrate the potential of the biosensor for food analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Induced Förster resonance energy transfer by encapsulation of DNA-scaffold based probes inside a plant virus based protein cage

NASA Astrophysics Data System (ADS)

de Ruiter, Mark V.; Overeem, Nico J.; Singhai, Gaurav; Cornelissen, Jeroen J. L. M.

2018-05-01

Insight into the assembly and disassembly of viruses can play a crucial role in developing cures for viral diseases. Specialized fluorescent probes can benefit the study of interactions within viruses, especially during cell studies. In this work, we developed a strategy based on Förster resonance energy transfer (FRET) to study the assembly of viruses without labeling the exterior of viruses. Instead, we exploit their encapsulation of nucleic cargo, using three different fluorescent ATTO dyes linked to single-stranded DNA oligomers, which are hybridised to a longer DNA strand. FRET is induced upon assembly of the cowpea chlorotic mottle virus, which forms monodisperse icosahedral particles of about 22 nm, thereby increasing the FRET efficiency by a factor of 8. Additionally, encapsulation of the dyes in virus-like particles induces a two-step FRET. When the formed constructs are disassembled, this FRET signal is fully reduced to the value before encapsulation. This reversible behavior makes the system a good probe for studying viral assembly and disassembly. It, furthermore, shows that multi-component supramolecular materials are stabilized in the confinement of a protein cage.

Purification of Houttuynia cordata Thunb. Essential Oil Using Macroporous Resin Followed by Microemulsion Encapsulation to Improve Its Safety and Antiviral Activity.

PubMed

Pang, Jianmei; Dong, Wujun; Li, Yuhuan; Xia, Xuejun; Liu, Zhihua; Hao, Huazhen; Jiang, Lingmin; Liu, Yuling

2017-02-15

Essential oil extracted from Houttuynia cordata Thunb. ( H. cordata ) is widely used in traditional Chinese medicine due to its excellent biological activities. However, impurities and deficient preparations of the essential oil limit its safety and effectiveness. Herein, we proposed a strategy to prepare H. cordata essential oil (HEO) safely and effectively by combining the solvent extraction and the macroporous resin purification flexibly, and then encapsulating it using microemulsion. The extraction and purification process were optimized by orthogonal experimental design and adsorption-desorption tests, respectively. The average houttuynin content in pure HEO was then validated at 44.3% ± 2.01%, which presented a great potential for industrial application. Subsequently, pure HEO-loaded microemulsion was prepared by high-pressure homogenization and was then fully characterized. Results showed that the pure HEO-loaded microemulsion was successfully prepared with an average particle size of 179.1 nm and a high encapsulation rate of 94.7%. Furthermore, safety evaluation tests and in vitro antiviral testing indicated that the safety and activity of HEO were significantly improved after purification using D101 resin and were further improved by microemulsion encapsulation. These results demonstrated that the purification of HEO by macroporous resin followed by microemulsion encapsulation would be a promising approach for industrial application of HEO for the antiviral therapies.

Substrate-permeable encapsulation of enzymes maintains effective activity, stabilizes against denaturation, and protects against proteolytic degradation.

PubMed

Nasseau, M; Boublik, Y; Meier, W; Winterhalter, M; Fournier, D

2001-12-05

How can enzymes be protected against denaturation and proteolysis while keeping them in a fully functional state? One solution is to encapsulate the enzymes into liposomes, which enhances their stability against denaturation and proteases. However, the permeability barrier of the lipid membrane drastically reduces the activity of enzyme entrapped in the liposome by reducing the internal concentration of the substrate. To overcome this problem, we permeabilized the wall of the liposome by reconstitution of a porin from Escherichia coli. In this way, we recovered the full functionality of the enzyme while retaining the protection against denaturation and proteolytic enzymes. Copyright 2001 John Wiley & Sons, Inc.

Fully integrated and encapsulated micro-fabricated vacuum diode and method of manufacturing same

DOEpatents

Resnick, Paul J.; Langlois, Eric

2015-12-01

Disclosed is an encapsulated micro-diode and a method for producing same. The method comprises forming a plurality columns in the substrate with a respective tip disposed at a first end of the column, the tip defining a cathode of the diode; disposing a sacrificial oxide layer on the substrate, plurality of columns and respective tips; forming respective trenches in the sacrificial oxide layer around the columns; forming an opening in the sacrificial oxide layer to expose a portion of the tips; depositing a conductive material in of the opening and on a surface of the substrate to form an anode of the diode; and removing the sacrificial oxide layer.

Method of manufacturing a fully integrated and encapsulated micro-fabricated vacuum diode

DOEpatents

Resnick, Paul J.; Langlois, Eric

2014-08-26

Disclosed is an encapsulated micro-diode and a method for producing same. The method comprises forming a plurality columns in the substrate with a respective tip disposed at a first end of the column, the tip defining a cathode of the diode; disposing a sacrificial oxide layer on the substrate, plurality of columns and respective tips; forming respective trenches in the sacrificial oxide layer around the columns; forming an opening in the sacrificial oxide layer to expose a portion of the tips; depositing a conductive material in of the opening and on a surface of the substrate to form an anode of the diode; and removing the sacrificial oxide layer.

Evolution of availability of curcumin inside poly-lactic-co-glycolic acid nanoparticles: impact on antioxidant and antinitrosant properties

PubMed Central

Betbeder, Didier; Lipka, Emmanuelle; Howsam, Mike; Carpentier, Rodolphe

2015-01-01

Purpose Curcumin exhibits antioxidant properties potentially beneficial for human health; however, its use in clinical applications is limited by its poor solubility and relative instability. Nanoparticles exhibit interesting features for the efficient distribution and delivery of curcumin into cells, and could also increase curcumin stability in biological systems. There is a paucity of information regarding the evolution of the antioxidant properties of nanoparticle-encapsulated curcumin. Method We described a simple method of curcumin encapsulation in poly-lactic-co-glycolic acid (PLGA) nanoparticles without the use of detergent. We assessed, in epithelial cells and in an acellular model, the evolution of direct antioxidant and antinitrosant properties of free versus PLGA-encapsulated curcumin after storage under different conditions (light vs darkness, 4°C vs 25°C vs 37°C). Results In epithelial cells, endocytosis and efflux pump inhibitors showed that the increased antioxidant activity of PLGA-encapsulated curcumin relied on bypassing the efflux pump system. Acellular assays showed that the antioxidant effect of curcumin was greater when loaded in PLGA nanoparticles. Furthermore, we observed that light decreased, though heat restored, antioxidant activity of PLGA-encapsulated curcumin, probably by modulating the accessibility of curcumin to reactive oxygen species, an observation supported by results from quenching experiments. Moreover, we demonstrated a direct antinitrosant activity of curcumin, enhanced by PLGA encapsulation, which was increased by light exposure. Conclusion These results suggest that the antioxidant and antinitrosant activities of encapsulated curcumin are light sensitive and that nanoparticle modifications over time and with temperature may facilitate curcumin contact with reactive oxygen species. These results highlight the importance of understanding effects of nanoparticle maturation on an encapsulated drug’s activity. PMID:26345627

Thermal Stabilization of Biologics with Photoresponsive Hydrogels.

PubMed

Sridhar, Balaji V; Janczy, John R; Hatlevik, Øyvind; Wolfson, Gabriel; Anseth, Kristi S; Tibbitt, Mark W

2018-03-12

Modern medicine, biological research, and clinical diagnostics depend on the reliable supply and storage of complex biomolecules. However, biomolecules are inherently susceptible to thermal stress and the global distribution of value-added biologics, including vaccines, biotherapeutics, and Research Use Only (RUO) proteins, requires an integrated cold chain from point of manufacture to point of use. To mitigate reliance on the cold chain, formulations have been engineered to protect biologics from thermal stress, including materials-based strategies that impart thermal stability via direct encapsulation of the molecule. While direct encapsulation has demonstrated pronounced stabilization of proteins and complex biological fluids, no solution offers thermal stability while enabling facile and on-demand release from the encapsulating material, a critical feature for broad use. Here we show that direct encapsulation within synthetic, photoresponsive hydrogels protected biologics from thermal stress and afforded user-defined release at the point of use. The poly(ethylene glycol) (PEG)-based hydrogel was formed via a bioorthogonal, click reaction in the presence of biologics without impact on biologic activity. Cleavage of the installed photolabile moiety enabled subsequent dissolution of the network with light and release of the encapsulated biologic. Hydrogel encapsulation improved stability for encapsulated enzymes commonly used in molecular biology (β-galactosidase, alkaline phosphatase, and T4 DNA ligase) following thermal stress. β-galactosidase and alkaline phosphatase were stabilized for 4 weeks at temperatures up to 60 °C, and for 60 min at 85 °C for alkaline phosphatase. T4 DNA ligase, which loses activity rapidly at moderately elevated temperatures, was protected during thermal stress of 40 °C for 24 h and 60 °C for 30 min. These data demonstrate a general method to employ reversible polymer networks as robust excipients for thermal stability of complex biologics during storage and shipment that additionally enable on-demand release of active molecules at the point of use.

Formulation of Nanoliposomal Vitamin D3 for Potential Application in Beverage Fortification

PubMed Central

Mohammadi, Maryam; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2014-01-01

Purpose: Vitamin D, a liposoluble vitamin has many benefits on health. Encapsulation of bioactives in lipid-based carrier systems like nanoliposomes preserves their native properties against oxidation over time along with providing its stable aqueous dispersion. Methods: In the current study, vitamin D3 nanoliposomes were prepared using thin-film hydration-sonication method and fully characterized by different instrumental techniques. Results: According to FTIR and DSC results, no interaction was observed between encapsulated nutraceutical and liposome constituents. The particle size and size distribution (Span value) were calculated 82–90 nm and 0.70–0.85, respectively. TEM analysis showed nano sized globular and bilayer vesicles. In all formations, the encapsulation efficiency of vitamin D3 was calculated more than 93%. Addition of cholesterol to lecithin bilayer increased the negative zeta potential from -29 to -43mV. Conclusion: The results of this study concluded that the liposomal nanoparticles may be introduced as a suitable carrier for fortification of beverages with vitamin D3. PMID:25671191

PCLC flake-based apparatus and method

DOEpatents

Cox, Gerald P; Fromen, Cathy A; Marshall, Kenneth L; Jacobs, Stephen D

2012-10-23

A PCLC flake/fluid host suspension that enables dual-frequency, reverse drive reorientation and relaxation of the PCLC flakes is composed of a fluid host that is a mixture of: 94 to 99.5 wt % of a non-aqueous fluid medium having a dielectric constant value .di-elect cons., where 1<.di-elect cons.<7, a conductivity value .sigma., where 10.sup.-9>.sigma.>10.sup.-7 Siemens per meter (S/m), and a resistivity r, where 10.sup.7>r>10.sup.10 ohm-meters (.OMEGA.-m), and which is optically transparent in a selected wavelength range .DELTA..lamda.; 0.0025 to 0.25 wt % of an inorganic chloride salt; 0.0475 to 4.75 wt % water; and 0.25 to 2 wt % of an anionic surfactant; and 1 to 5 wt % of PCLC flakes suspended in the fluid host mixture. Various encapsulation forms and methods are disclosed including a Basic test cell, a Microwell, a Microcube, Direct encapsulation (I), Direct encapsulation (II), and Coacervation encapsulation. Applications to display devices are disclosed.

3D bioprinting of scaffolds with living Schwann cells for potential nerve tissue engineering applications.

PubMed

Ning, Liqun; Sun, Haoying; Lelong, Tiphanie; Guilloteau, Romain; Zhu, Ning; Schreyer, David J; Chen, Daniel Xiongbiao

2018-06-18

Three-dimensional (3D) bioprinting of biomaterials shows great potential for producing cell-encapsulated scaffolds to repair nerves after injury or disease. For this, preparation of biomaterials and bioprinting itself are critical to create scaffolds with both biological and mechanical properties appropriate for nerve regeneration, yet remain unachievable. This paper presents our study on bioprinting Schwann cell-encapsulated scaffolds using composite hydrogels of alginate, fibrin, hyaluronic acid, and/or RGD peptide, for nerve tissue engineering applications. For the preparation of composite hydrogels, suitable hydrogel combinations were identified and prepared by adjusting the concentration of fibrin based on the morphological spreading of Schwann cells. In bioprinting, the effects of various printing process parameters (including the air pressure for dispensing, dispensing head movement speed, and crosslinking conditions) on printed structures were investigated and, by regulating these parameters, mechanically-stable scaffolds with fully interconnected pores were printed. The performance of Schwann cells within the printed scaffolds were examined in terms of viability, proliferation, orientation, and ability to produce laminin. Our results show that the printed scaffolds can promote the alignment of Schwann cells inside scaffolds and thus provide haptotactic cues to direct the extension of dorsal root ganglion neurites along the printed strands, demonstrating their great potential for applications in the field of nerve tissue engineering. © 2018 IOP Publishing Ltd.

Polymeric Packaging for Fully Implantable Wireless Neural Microsensors

PubMed Central

Aceros, Juan; Yin, Ming; Borton, David A.; Patterson, William R.; Bull, Christopher; Nurmikko, Arto V.

2014-01-01

We present polymeric packaging methods used for subcutaneous, fully implantable, broadband, and wireless neurosensors. A new tool for accelerated testing and characterization of biocompatible polymeric packaging materials and processes is described along with specialized test units to simulate our fully implantable neurosensor components, materials and fabrication processes. A brief description of the implantable systems is presented along with their current encapsulation methods based on polydimethylsiloxane (PDMS). Results from in-vivo testing of multiple implanted neurosensors in swine and non-human primates are presented. Finally, a novel augmenting polymer thin film material to complement the currently employed PDMS is introduced. This thin layer coating material is based on the Plasma Enhanced Chemical Vapor Deposition (PECVD) process of Hexamethyldisiloxane (HMDSO) and Oxygen (O2). PMID:23365999

In-situ formation of nanoparticles within a silicon-based matrix

DOEpatents

Thoma, Steven G [Albuquerque, NM; Wilcoxon, Jess P [Albuquerque, NM; Abrams, Billie L [Albuquerque, NM

2008-06-10

A method for encapsulating nanoparticles with an encapsulating matrix that minimizes aggregation and maintains favorable properties of the nanoparticles. The matrix comprises silicon-based network-forming compounds such as ormosils and polysiloxanes. The nanoparticles are synthesized from precursors directly within the silicon-based matrix.

GOES-R Encapsulation

NASA Image and Video Library

2016-10-21

The two halves of the payload fairing are fully closed around the Geostationary Operational Environmental Satellite (GOES-R) inside the Astrotech payload processing facility in Titusville, Florida near NASA’s Kennedy Space Center. GOES-R will be the first satellite in a series of next-generation NOAA GOES Satellites. The spacecraft is to launch aboard a United Launch Alliance Atlas V rocket in November.

Novel Thermal Powered Technology for UUV Persistent Surveillance

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Chao, Yi

2006-01-01

Buoyancy Generation: Various technology attempts include melting a wax, which pushes directly against a piston (U.S. Patent 5,291,847) or against a bladder (Webb Research), using ammonia or Freon 21 (U.S. Patent 5,303,552), and using solar heat to expand an oil (www.space.com, April, 10, 2002). All these heat-activated buoyancy control designs have thus far proved impractical and have ultimately failed during repeated cycling in ocean testing. JPL has demonstrated fully reversible 10 C encapsulated wax phase change, which can be used to change buoyancy without electrical hydraulic pumps. This technique has greatly improved heat transfer and much better reversibility than previous designs. Power Generation: Ocean Thermal Energy Conversion (OTEC) systems have been designed that transfer deep, cold sea water to the surface to generate electricity using turbine cycles with ammonia or water as the working fluid. JPL has designed several UUV systems: 1) Using a propeller water turbine to generate power on a gliding submersible; 2) Employing a compact CO2 turbine cycle powered by moving through thermoclines; and 3) Using melted wax to directly produce power through a piston-geared generator.

Mapping microbubble viscosity using fluorescence lifetime imaging of molecular rotors

PubMed Central

Hosny, Neveen A.; Mohamedi, Graciela; Rademeyer, Paul; Owen, Joshua; Wu, Yilei; Tang, Meng-Xing; Eckersley, Robert J.; Stride, Eleanor; Kuimova, Marina K.

2013-01-01

Encapsulated microbubbles are well established as highly effective contrast agents for ultrasound imaging. There remain, however, some significant challenges to fully realize the potential of microbubbles in advanced applications such as perfusion mapping, targeted drug delivery, and gene therapy. A key requirement is accurate characterization of the viscoelastic surface properties of the microbubbles, but methods for independent, nondestructive quantification and mapping of these properties are currently lacking. We present here a strategy for performing these measurements that uses a small fluorophore termed a “molecular rotor” embedded in the microbubble surface, whose fluorescence lifetime is directly related to the viscosity of its surroundings. We apply fluorescence lifetime imaging to show that shell viscosities vary widely across the population of the microbubbles and are influenced by the shell composition and the manufacturing process. We also demonstrate that heterogeneous viscosity distributions exist within individual microbubble shells even with a single surfactant component. PMID:23690599

Light-triggered in vivo activation of adhesive peptides regulates cell adhesion, inflammation and vascularization of biomaterials.

PubMed

Lee, Ted T; García, José R; Paez, Julieta I; Singh, Ankur; Phelps, Edward A; Weis, Simone; Shafiq, Zahid; Shekaran, Asha; Del Campo, Aránzazu; García, Andrés J

2015-03-01

Materials engineered to elicit targeted cellular responses in regenerative medicine must display bioligands with precise spatial and temporal control. Although materials with temporally regulated presentation of bioadhesive ligands using external triggers, such as light and electric fields, have recently been realized for cells in culture, the impact of in vivo temporal ligand presentation on cell-material responses is unknown. Here, we present a general strategy to temporally and spatially control the in vivo presentation of bioligands using cell-adhesive peptides with a protecting group that can be easily removed via transdermal light exposure to render the peptide fully active. We demonstrate that non-invasive, transdermal time-regulated activation of cell-adhesive RGD peptide on implanted biomaterials regulates in vivo cell adhesion, inflammation, fibrous encapsulation, and vascularization of the material. This work shows that triggered in vivo presentation of bioligands can be harnessed to direct tissue reparative responses associated with implanted biomaterials.

Light-triggered in vivo activation of adhesive peptides regulates cell adhesion, inflammation and vascularization of biomaterials

NASA Astrophysics Data System (ADS)

Lee, Ted T.; García, José R.; Paez, Julieta I.; Singh, Ankur; Phelps, Edward A.; Weis, Simone; Shafiq, Zahid; Shekaran, Asha; Del Campo, Aránzazu; García, Andrés J.

2015-03-01

Materials engineered to elicit targeted cellular responses in regenerative medicine must display bioligands with precise spatial and temporal control. Although materials with temporally regulated presentation of bioadhesive ligands using external triggers, such as light and electric fields, have recently been realized for cells in culture, the impact of in vivo temporal ligand presentation on cell-material responses is unknown. Here, we present a general strategy to temporally and spatially control the in vivo presentation of bioligands using cell-adhesive peptides with a protecting group that can be easily removed via transdermal light exposure to render the peptide fully active. We demonstrate that non-invasive, transdermal time-regulated activation of cell-adhesive RGD peptide on implanted biomaterials regulates in vivo cell adhesion, inflammation, fibrous encapsulation, and vascularization of the material. This work shows that triggered in vivo presentation of bioligands can be harnessed to direct tissue reparative responses associated with implanted biomaterials.

Tungsten-encapsulated gadolinium nanoislands with enhanced magnetocaloric response

DOE PAGES

Logan, Jonathan M.; Rosenmann, Daniel; Sangpo, Tenzin; ...

2017-07-03

Here, we report a method for growing chemically pure, oxide-free, air-stable Gd nanoislands with enhanced magnetic properties. These nanoislands are grown by solid-state dewetting and are fully encapsulated in tungsten such that they remain stable in ambient environments. They display good crystalline properties with hexagonally close-packed crystal structure and strong preferential orientation. We show that the choice of substrate strongly affects their shape, crystal orientation, and magnetic properties. The temperature-dependent magnetic coercivity and remanence of the Gd islands can vary by as much as a factor of three depending on the substrate used. The magneto- caloric properties of Gd islandsmore » grown on a sapphire substrate exceed those of high-quality Gd thin films.« less

The influence of bile acids on the oral bioavailability of vitamin K encapsulated in polymeric micelles.

PubMed

van Hasselt, P M; Janssens, G E P J; Slot, T K; van der Ham, M; Minderhoud, T C; Talelli, M; Akkermans, L M; Rijcken, C J F; van Nostrum, C F

2009-01-19

The purpose of this study was to assess the ability of polymeric micelles to enable gastrointestinal absorption of the extremely hydrophobic compound vitamin K, by comparison of its absorption in bile duct ligated and sham operated rats. Hereto, vitamin K was encapsulated in micelles composed of mPEG(5000)-b-p(HPMAm-lac(2)), a thermosensitive block copolymer. Vitamin K plasma levels rose significantly upon gastric administration of 1 mg vitamin K encapsulated in polymeric micelles in sham operated rats, but not after bile duct ligation (AUC 4543 and 1.64 ng/mL/h respectively, p<0.01). Duodenal administration of polymeric micelles together with bile acids in bile duct ligated rats fully restored absorption. Dynamic light scattering time series showed a significant and dose dependent rise in micellar size in the presence of bile acids in vitro, indicating the gradual formation of mixed micelles during the first 3 h of incubation. The highest bile acid amounts (11 mM deoxycholic acid and 41 mM taurocholic acid) eventually caused aggregation of the loaded micelles after the formation of mixed micelles. These data suggest that the gastrointestinal absorption of encapsulated vitamin K from polymeric micelles is mediated by free bile and that uptake of intact micelles through pinocytosis is insignificant.

Non-covalent interactions of a drug molecule encapsulated in a hybrid silica gel.

PubMed

Paul, Geo; Steuernagel, Stefan; Koller, Hubert

2007-12-28

The drug molecule Propranolol has been encapsulated by a sol-gel process in an organic-inorganic hybrid matrix by in-situ self-assembly; the 2D HETCOR solid state NMR spectroscopy provides direct proof of the intimate spatial relationship between the host matrix and guest drug molecules.

Children Reorient Using the Left/Right Sense of Coloured Landmarks at 18-24 Months

ERIC Educational Resources Information Center

Nardini, Marko; Atkinson, Janette; Burgess, Neil

2008-01-01

In previous studies, children disoriented in small enclosures used room shape, but not wall colors, to find hidden objects. Their reorientation was said to depend solely on a "geometric module" informationally encapsulated with respect to color. We argue that previous studies did not fully evaluate children's use of color owing to a bias in the…

Probing quantum Hall states with single-electron transistors at high magnetic fields

NASA Astrophysics Data System (ADS)

Gustafsson, Martin; Yankowitz, Matthew; Forsythe, Carlos; Zhu, Xiaoyang; Dean, Cory

The sequence of fractional quantum Hall states in graphene is not yet fully understood, largely due to disorder-induced limitations of conventional transport studies. Measurements of magnetotransport in other 2D crystals are further complicated by the difficulties in making ohmic contact to the materials. On the other hand, bulk electronic compressibility can provide clear signatures of the integer and fractional quantum Hall effects, does not require ohmic contact, and can be localized to regions of low disorder. The single-electron transistor (SET) is a suitable tool for such experiments due to its small size and high charge sensitivity, which allow electric fields penetrating the 2D electron system to be detected locally and with high fidelity. Here we report studies of exfoliated 2D van der Waals materials fully encapsulated in flakes of hexagonal boron nitride. SETs are fabricated lithographically on top of the encapsulation, yielding a structure which lends itself to experiments at high electric and magnetic fields. We demonstrate the method on monolayer graphene, where we observe fractional quantum Hall states at all filling factors ν = n / 3 up to n = 17 and extract their associated energy gaps for magnetic fields up to 31 tesla.

Photovoltaic module with adhesion promoter

DOEpatents

Xavier, Grace

2013-10-08

Photovoltaic modules with adhesion promoters and methods for fabricating photovoltaic modules with adhesion promoters are described. A photovoltaic module includes a solar cell including a first surface and a second surface, the second surface including a plurality of interspaced back-side contacts. A first glass layer is coupled to the first surface by a first encapsulating layer. A second glass layer is coupled to the second surface by a second encapsulating layer. At least a portion of the second encapsulating layer is bonded directly to the plurality of interspaced back-side contacts by an adhesion promoter.

Photovoltaic module and laminate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunea, Gabriela E.; Kim, Sung Dug; Kavulak, David F.J.

A photovoltaic module is disclosed. The photovoltaic module has a first side directed toward the sun during normal operation and a second, lower side. The photovoltaic module comprises a perimeter frame and a photovoltaic laminate at least partially enclosed by and supported by the perimeter frame. The photovoltaic laminate comprises a transparent cover layer positioned toward the first side of the photovoltaic module, an upper encapsulant layer beneath and adhering to the cover layer, a plurality of photovoltaic solar cells beneath the upper encapsulant layer, the photovoltaic solar cells electrically interconnected, a lower encapsulant layer beneath the plurality of photovoltaicmore » solar cells, the upper and lower encapsulant layers enclosing the plurality of photovoltaic solar cells, and a homogenous rear environmental protection layer, the rear environmental protection layer adhering to the lower encapsulant layer, the rear environmental protection layer exposed to the ambient environment on the second side of the photovoltaic module.« less

Encapsulation of fluorescence vegetable extracts within a templated sol-gel matrix

NASA Astrophysics Data System (ADS)

Lacatusu, Ioana; Badea, Nicoleta; Nita, Rodica; Murariu, Alina; Miculescu, Florin; Iosub, Ion; Meghea, Aurelia

2010-04-01

The sol-gel encapsulation of labile substances with specific properties and recognition functions within robust polymer matrices remains a challenging task, despite the considerable research that has been focused on this field. Numerous studies have been reported in the field of sol-gel processes regarding different physical and chemical packing of sensitive biomolecules encapsulated in silica matrix. In this paper the classical sol-gel synthesis has been used under mild conditions in order to minimize denaturizing effects on encapsulated active vegetable extracts from flavones class. The silica templated matrix was obtained by using two types of surfactants with different alkyl chain (didodecyldimethyl-ammonium bromide and trioctadecylmetilammonium bromide) as structure-directing agents for the silicon oxide framework. An organic precursor of silicic acid (triethoxymethylsilane) has been used and it was processed by competitive hydrolysis and polycondensation reactions under controlled directions assured by the presence of oriented template. Silica materials thus obtained are used for encapsulation of two flavonoid samples containing as active principles two sources: rutin and a vegetable extract from Begonia plant. The synthesis of encapsulated nanocompounds has been achieved taking into consideration the specific interaction between the colloidal gel precursors and molecular structures of selected biomolecules. The main objective was to improve the encapsulation conditions for specific biomolecules, searching for the highest stability and functionality without loosing the quality of the flavonoid properties, particularly optical properties like fluorescence. The structural properties of the encapsulated samples have been studied by FT-IR and UV-VIS spectroscopy, thermal analysis and SEM/EDX analysis. The fluorescence experiments showed that, in the case of all four encapsulated samples, the fluorescence spectra manifest a significant increase in intensity signals, with more than 10 times for individual flavonoid and 50 times for Begonia extract. This behaviour are mainly assigned to the physical interaction of flavonoid molecules with the residual hydroxyl groups of silica, excellent synergistic properties of silica and the favourable conformation arrangement of organic molecules inside the silica network. The size distribution of synthesised polymeric silica materials have been investigated by dynamic light scattering (DLS) and optical microscopy.

Variability in Heat Strain in Fully Encapsulated Impermeable Suits in Different Climates and at Different Work Loads.

PubMed

DenHartog, Emiel A; Rubenstein, Candace D; Deaton, A Shawn; Bogerd, Cornelis Peter

2017-03-01

A major concern for responders to hazardous materials (HazMat) incidents is the heat strain that is caused by fully encapsulated impermeable (NFPA 1991) suits. In a research project, funded by the US Department of Defense, the thermal strain experienced when wearing these suits was studied. Forty human subjects between the ages of 25 and 50 participated in a protocol approved by the local ethical committee. Six different fully encapsulated impermeable HazMat suits were evaluated in three climates: moderate (24°C, 50% RH, 20°C WBGT), warm-wet (32°C, 60% RH, 30°C WBGT), and hot-dry (45°C, 20% RH, 37°C WBGT, 200 W m-2 radiant load) and at three walking speeds: 2.5, 4, and 5.5 km h-1. The medium speed, 4 km h-1, was tested in all three climates and the other two walking speeds were only tested in the moderate climate. Prior to the test a submaximal exercise test in normal clothing was performed to determine a relationship between heart rate and oxygen consumption (pretest). In total, 163 exposures were measured. Tolerance time ranged from as low as 20 min in the hot-dry condition to 60 min (the maximum) in the moderate climate, especially common at the lowest walking speed. Between the six difference suits limited differences were found, a two-layered aluminized suit exhibited significant shorter tolerance times in the moderate climate, but no other major significant differences were found for the other climates or workloads. An important characteristic of the overall dataset is the large variability between the subjects. Although the average responses seem suitable to be predicted, the variability in the warmer strain conditions ranged from 20 min up to 60 min. The work load in these encapsulated impermeable suits was also significantly higher than working in normal clothing and higher than predicted by the Pandolf equation. Heart rate showed a very strong correlation to body core temperature and was in many cases the limiting factor. Setting the heart rate maximum at 80% of predicted individual maximum (age based) would have prevented 95% of the cases with excessive heat strain. Monitoring of heart rate under operational conditions would further allow individually optimize working times and help in preventing exertional heat stroke. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Integrated Glass Coating Manufacturing Line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brophy, Brenor

2015-09-30

This project aims to enable US module manufacturers to coat glass with Enki’s state of the art tunable functionalized AR coatings at the lowest possible cost and highest possible performance by encapsulating Enki’s coating process in an integrated tool that facilitates effective process improvement through metrology and data analysis for greater quality and performance while reducing footprint, operating and capital costs. The Phase 1 objective was a fully designed manufacturing line, including fully specified equipment ready for issue of purchase requisitions; a detailed economic justification based on market prices at the end of Phase 1 and projected manufacturing costs andmore » a detailed deployment plan for the equipment.« less

Effect of alginate microencapsulation on the catalytic efficiency and in vitro enzyme-prodrug therapeutic efficacy of cytosine deaminase and of recombinant E. coli expressing cytosine deaminase.

PubMed

Funaro, Michael G; Nemani, Krishnamurthy V; Chen, Zhihang; Bhujwalla, Zaver M; Griswold, Karl E; Gimi, Barjor

2016-02-01

Cytosine deaminase (CD) catalyses the enzymatic conversion of the non-toxic prodrug 5-fluorocytosine (5-FC) to the potent chemotherapeutic form, 5-fluorouracil (5-FU). Intratumoral delivery of CD localises chemotherapy dose while reducing systemic toxicity. Encapsulation in biocompatible microcapsules immunoisolates CD and protects it from degradation. We report on the effect of alginate encapsulation on the catalytic and functional activity of isolated CD and recombinant E. coli engineered to express CD (E. coli(CD)). Alginate microcapsules containing either CD or Escherichia coli(CD) were prepared using ionotropic gelation. Conversion of 5-FC to 5-FU was quantitated in unencapsulated and encapsulated CD/E. coli(CD) using spectrophotometry, with a slower rate of conversion observed following encapsulation. Both encapsulated CD/5-FC and E. coli(CD)/5-FC resulted in cell kill and reduced proliferation of 9 L rat glioma cells, which was comparable to direct 5-FU treatment. Our results show that encapsulation preserves the therapeutic potential of CD and E. coli(CD) is equally effective for enzyme-prodrug therapy.

Endo-Fullerene and Doped Diamond Nanocrystallite Based Models of Qubits for Solid-State Quantum Computers

NASA Technical Reports Server (NTRS)

Park, Seongjun; Srivastava, Deepak; Cho, Kyeongjae; Biegel, Bryan (Technical Monitor)

2001-01-01

Models of encapsulated 1/2 nuclear spin H-1 and P-31 atoms in fullerene and diamond nanocrystallite, respectively, are proposed and examined with ab-initio local density functional method for possible applications as single quantum bits (qubits) in solid-state quantum computers. A H-1 atom encapsulated in a fully deuterated fullerene, C(sub 20)D(sub 20), forms the first model system and ab-initio calculation shows that H-1 atom is stable in atomic state at the center of the fullerene with a barrier of about 1 eV to escape. A P-31 atom positioned at the center of a diamond nanocrystallite is the second model system, and 3 1P atom is found to be stable at the substitutional site relative to interstitial sites by 15 eV, Vacancy formation energy is 6 eV in diamond so that substitutional P-31 atom will be stable against diffusion during the formation mechanisms within the nanocrystallite. The coupling between the nuclear spin and weakly bound (valance) donor electron coupling in both systems is found to be suitable for single qubit applications, where as the spatial distributions of (valance) donor electron wave functions are found to be preferentially spread along certain lattice directions facilitating two or more qubit applications. The feasibility of the fabrication pathways for both model solid-state qubit systems within practical quantum computers is discussed with in the context of our proposed solid-state qubits.

Programmed death-ligand 1 expression by digital image analysis advances thyroid cancer diagnosis among encapsulated follicular lesions.

PubMed

Hsieh, Anne M-Y; Polyakova, Olena; Fu, Guodong; Chazen, Ronald S; MacMillan, Christina; Witterick, Ian J; Ralhan, Ranju; Walfish, Paul G

2018-04-13

Recognition of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) that distinguishes them from invasive malignant encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) can prevent overtreatment of NIFTP patients. We and others have previously reported that programmed death-ligand 1 (PD-L1) is a useful biomarker in thyroid tumors; however, all reports to date have relied on manual scoring that is time consuming as well as subject to individual bias. Consequently, we developed a digital image analysis (DIA) protocol for cytoplasmic and membranous stain quantitation (ThyApp) and evaluated three tumor sampling methods [Systemic Uniform Random Sampling, hotspot nucleus, and hotspot nucleus/3,3'-Diaminobenzidine (DAB)]. A patient cohort of 153 cases consisting of 48 NIFTP, 44 EFVPTC, 26 benign nodules and 35 encapsulated follicular lesions/neoplasms with lymphocytic thyroiditis (LT) was studied. ThyApp quantitation of PD-L1 expression revealed a significant difference between invasive EFVPTC and NIFTP; but none between NIFTP and benign nodules. ThyApp integrated with hotspot nucleus tumor sampling method demonstrated to be most clinically relevant, consumed least processing time, and eliminated interobserver variance. In conclusion, the fully automatic DIA algorithm developed using a histomorphological approach objectively quantitated PD-L1 expression in encapsulated thyroid neoplasms and outperformed manual scoring in reproducibility and higher efficiency.

Efficient in vitro encapsulation of protein cargo by an engineered protein container.

PubMed

Wörsdörfer, Bigna; Pianowski, Zbigniew; Hilvert, Donald

2012-01-18

An engineered variant of lumazine synthase, a nonviral capsid protein with a negatively charged luminal surface, is shown to encapsulate up to 100 positively supercharged green fluorescent protein (GFP) molecules in vitro. Packaging can be achieved starting either from intact, empty capsids or from capsid fragments by incubation with cargo in aqueous buffer. The yield of encapsulated GFP correlates directly with the host/guest mixing ratio, providing excellent control over packing density. Facile in vitro loading highlights the unusual structural dynamics of this novel nanocontainer and should facilitate diverse biotechnological and materials science applications. © 2011 American Chemical Society

Biodegradable polycaprolactone (PCL) nanosphere encapsulating superoxide dismutase and catalase enzymes.

PubMed

Singh, Sushant; Singh, Abhay Narayan; Verma, Anil; Dubey, Vikash Kumar

2013-12-01

Biodegradable polycaprolactone (PCL) nanosphere encapsulating superoxide dismutase (SOD) and catalase (CAT) were successfully synthesized using double emulsion (w/o/w) solvent evaporation technique. Characterization of the nanosphere using dynamic light scattering, field emission scanning electron microscope, and Fourier transform infrared spectroscopy revealed a spherical-shaped nanosphere in a size range of 812 ± 64 nm with moderate protein encapsulation efficiency of 55.42 ± 3.7 % and high in vitro protein release. Human skin HaCat cells were used for analyzing antioxidative properties of SOD- and CAT-encapsulated PCL nanospheres. Oxidative stress condition in HaCat cells was optimized with exposure to hydrogen peroxide (H2O2; 1 mM) as external stress factor and verified through reactive oxygen species (ROS) analysis using H2DCFDA dye. PCL nanosphere encapsulating SOD and CAT together indicated better antioxidative defense against H2O2-induced oxidative stress in human skin HaCat cells in comparison to PCL encapsulating either SOD or CAT alone as well as against direct supplement of SOD and CAT protein solution. Increase in HaCat cells SOD and CAT activities after treatment hints toward uptake of PCL nanosphere into the human skin HaCat cells. The result signifies the role of PCL-encapsulating SOD and CAT nanosphere in alleviating oxidative stress.

Thin-film encapsulation of organic electronic devices based on vacuum evaporated lithium fluoride as protective buffer layer

NASA Astrophysics Data System (ADS)

Peng, Yingquan; Ding, Sihan; Wen, Zhanwei; Xu, Sunan; Lv, Wenli; Xu, Ziqiang; Yang, Yuhuan; Wang, Ying; Wei, Yi; Tang, Ying

2017-03-01

Encapsulation is indispensable for organic thin-film electronic devices to ensure reliable operation and long-term stability. For thin-film encapsulating organic electronic devices, insulating polymers and inorganic metal oxides thin films are widely used. However, spin-coating of insulating polymers directly on organic electronic devices may destroy or introduce unwanted impurities in the underlying organic active layers. And also, sputtering of inorganic metal oxides may damage the underlying organic semiconductors. Here, we demonstrated that by utilizing vacuum evaporated lithium fluoride (LiF) as protective buffer layer, spin-coated insulating polymer polyvinyl alcohol (PVA), and sputtered inorganic material Er2O3, can be successfully applied for thin film encapsulation of copper phthalocyanine (CuPc)-based organic diodes. By encapsulating with LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films, the device lifetime improvements of 10 and 15 times can be achieved. These methods should be applicable for thin-film encapsulation of all kinds of organic electronic devices. Moisture-induced hole trapping, and Al top electrode oxidation are suggest to be the origins of current decay for the LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films encapsulated devices, respectively.

Dynamics of encapsulated microbubbles for contrast ultrasound imaging and drug delivery: from pressure dependent subharmonic to collapsing jet and acoustic streaming

NASA Astrophysics Data System (ADS)

Sarkar, Kausik

2016-11-01

Intravenously injected microbubbles used as ultrasound contrast enhancing agents are encapsulated by a nanometer-thick layer of lipids, proteins or polymers to stabilize them against premature dissolution. Over the years, we have developed interfacial rheological models for the encapsulation and used them to characterize several contrast agents by acoustic means. We will present an overview of our research emphasizing recent efforts in two directions. The first is on using subharmonic signals from the contrast microbubbles for non-invasive pressure estimation. Experimental measurement and modeling show that the subharmonic signal can both increase or decrease with pressure depending on frequency. Secondly, we will discuss boundary element (BEM) simulation of the collapse of an encapsulated microbubbles forming a jet near a blood vessel wall. Different rheology models of the encapsulation have been rigorously implemented in the BEM formulation. We will discuss the resulting stresses and the acoustic streaming near the wall leading to sonoporation and other bioeffects. Partially supported by Natinal Science Foundation.

Integration of living cells into nanostructures using non-conventional self-assembly

NASA Astrophysics Data System (ADS)

Carnes, Eric C.

Patternable cell immobilization is an essential feature of any solid-state device designed for interrogating or exploiting living cells. Immobilized cells must remain viable in a robust matrix that promotes fluidic connectivity between the cells and their environment while retaining the ability to establish and maintain necessary chemical gradients. A suitable inorganic matrix can be constructed via evaporation-induced self-assembly of nanostructured silica, in which phospholipids are used in place of traditional surfactant structure-directing agents in order to enhance cell viability and to create a coherent interface between the cell and the surrounding three-dimensional nanostructure. We have used this technique to develop two distinct cell encapsulation processes: cell-directed assembly and cell-directed integration. Cell-directed assembly is a one-step procedure that provides superior viability of immobilized cells by encouraging cells to interact with the developing host matrix. Limitations of this system include low viability for some cell types due to exposure to solvents and stresses, as well as a lack of control over the developing host nanostructure. Cell-directed integration addresses these shortcomings by introducing a two-step process in which cells become encapsulated in a pre-formed silica matrix. The validity of each encapsulation method has been demonstrated with Gram-positive and Gram-negative bacteria, yeast, and mammalian cells. The ability of the immobilized cells to establish relevant gradients of ions or signaling molecules, a key feature of these systems, has been characterized. Additionally, extension of cell encapsulation to address lingering questions in cell biology is addressed. We have also adapted these immobilization processes to be compatible with a variety of patterning strategies having tailorable properties. Widely available photolithography techniques, as well as direct aerosol deposition, have been adapted to provide methods for obtaining both positive and negative transfer of desired cell patterns. Multi-step lithography is also used to create a highly functional system allowing spatial control of not only cells but also media and other molecules of interest.

Spectral perturbations from silicon diode detector encapsulation and shielding in photon fields.

PubMed

Eklund, Karin; Ahnesjö, Anders

2010-11-01

Silicon diodes are widely used as detectors for relative dose measurements in radiotherapy. The common manufacturing practice is to encapsulate the diodes in plastic for protection and to facilitate mounting in scanning devices. Diodes intended for use in photon fields commonly also have a shield of a high atomic number material (usually tungsten) integrated into the encapsulation to selectively absorb low-energy photons to which silicon diodes would otherwise over-response. However, new response models based on cavity theories and spectra calculations have been proposed for direct correction of the readout from unshielded (e.g., "electron") diodes used in photon fields. This raises the question whether it is correct to assume that the spectrum in a water phantom at the location of the detector cavity is not perturbed by the detector encapsulation materials. The aim of this work is to investigate the spectral effects of typical encapsulations, including shielding, used for clinical diodes. The effects of detector encapsulation of an unshielded and a shielded commercial diode on the spectra at the detector cavity location are studied through Monte Carlo simulations with PENELOPE-2005. Variance reduction based on correlated sampling is applied to reduce the CPU time needed for the simulations. The use of correlated sampling is found to be efficient and to not introduce any significant bias to the results. Compared to reference spectra calculated in water, the encapsulation for an unshielded diode is demonstrated to not perturb the spectrum, while a tungsten shielded diode caused not only the desired decrease in low-energy scattered photons but also a large increase of the primary electron fluence. Measurements with a shielded diode in a 6 MV photon beam proved that the shielding does not completely remove the field-size dependence of the detector response caused by the over-response from low-energy photons. Response factors of a properly corrected unshielded diode were shown to give comparable, or better, results than the traditionally used shielded diode. Spectra calculated for photon fields in water can be directly used for modeling the response of unshielded silicon diodes with plastic encapsulations. Unshielded diodes used together with appropriate corrections can replace shielded diodes in photon dose measurements.

Three-Dimensional Encapsulation of Saccharomyces cerevisiae in Silicate Matrices Creates Distinct Metabolic States as Revealed by Gene Chip Analysis.

PubMed

Fazal, Zeeshan; Pelowitz, Jennifer; Johnson, Patrick E; Harper, Jason C; Brinker, C Jeffrey; Jakobsson, Eric

2017-04-25

In order to design hybrid cellular/synthetic devices such as sensors and vaccines, it is important to understand how the metabolic state of living cells changes upon physical confinement within three-dimensional (3D) matrices. We analyze the gene expression patterns of stationary phase Saccharomyces cerevisiae (S. cerevisiae) cells encapsulated within three distinct nanostructured silica matrices and relate those patterns to known naturally occurring metabolic states. Silica encapsulation methods employed were lipid-templated mesophase silica thin films formed by cell-directed assembly (CDA), lipid-templated mesophase silica particles formed by spray drying (SD), and glycerol-doped silica gel monoliths prepared from an aqueous silicate (AqS+g) precursor solution. It was found that the cells for all three-encapsulated methods enter quiescent states characteristic of response to stress, albeit to different degrees and with differences in detail. By the measure of enrichment of stress-related gene ontology categories, we find that the AqS+g encapsulation is more amenable to the cells than CDA and SD encapsulation. We hypothesize that this differential response in the AqS+g encapsulation is related to four properties of the encapsulating gel: (1) oxygen permeability, (2) relative softness of the material, (3) development of a protective sheath around individual cells (visible in TEM micrographs vide infra), and (4) the presence of glycerol in the gel, which has been previously noted to serve as a protectant for encapsulated cells and can serve as the sole carbon source for S. cerevisiae under aerobic conditions. This work represents a combination of experiment and analysis aimed at the design and development of 3D encapsulation procedures to induce, and perhaps control, well-defined physiological behaviors.

Microwave-assisted synthesis of cyclodextrin polyurethanes.

PubMed

Biswas, Atanu; Appell, Michael; Liu, Zengshe; Cheng, H N

2015-11-20

Cyclodextrin (CD) has often been incorporated into polyurethanes in order to facilitate its use in encapsulation or removal of organic species for various applications. In this work a microwave-assisted method has been developed to produce polyurethanes consisting of α-, β-, and γ-CD and three common diisocyanates. As compared to conventional heating, this new synthetic method saves energy, significantly reduces reaction time, and gets similar or improved yield. The reaction products have been fully characterized with (13)C, (1)H, and two-dimensional NMR spectroscopy. With suitable stoichiometry of starting CD and diisocyanate, the resulting CD polyurethane is organic-soluble and water-insoluble and is shown to remove Nile red dye and phenol from water. Possible applications include the removal of undesirable materials from process streams, toxic compounds from the environment, and encapsulation of color or fragrance molecules. Published by Elsevier Ltd.

A comparative study on top-gated and bottom-gated multilayer MoS2 transistors with gate stacked dielectric of Al2O3/HfO2.

PubMed

Zou, Xiao; Xu, Jingping; Huang, Hao; Zhu, Ziqang; Wang, Hongjiu; Li, Borui; Liao, Lei; Fang, Guojia

2018-06-15

Top-gated and bottom-gated transistors with multilayer MoS 2 channel fully encapsulated by stacked Al 2 O 3 /HfO 2 (9 nm/6 nm) were fabricated and comparatively studied. Excellent electrical properties are demonstrated for the TG transistors with high on-off current ratio of 10 8 , high field-effect mobility of 10 2 cm 2 V -1 s -1 , and low subthreshold swing of 93 mV dec -1 . Also, enhanced reliability has been achieved for the TG transistors with threshold voltage shift of 10 -3 -10 -2 V MV -1 cm -1 after 6 MV cm -1 gate-biased stressing. All improvement for the TG device can be ascribed to the formed device structure and dielectric environment. Degradation of the performance for the BG transistors should be attributed to reduced gate capacitance density and deteriorated interface properties related to vdW gap with a thickness about 0.4 nm. So, the TG transistor with MoS 2 channel fully encapsulated by stacked Al 2 O 3 /HfO 2 is a promising way to fabricate high-performance ML MoS 2 field-effect transistors for practical electron device applications.

A comparative study on top-gated and bottom-gated multilayer MoS2 transistors with gate stacked dielectric of Al2O3/HfO2

NASA Astrophysics Data System (ADS)

Zou, Xiao; Xu, Jingping; Huang, Hao; Zhu, Ziqang; Wang, Hongjiu; Li, Borui; Liao, Lei; Fang, Guojia

2018-06-01

Top-gated and bottom-gated transistors with multilayer MoS2 channel fully encapsulated by stacked Al2O3/HfO2 (9 nm/6 nm) were fabricated and comparatively studied. Excellent electrical properties are demonstrated for the TG transistors with high on–off current ratio of 108, high field-effect mobility of 102 cm2 V‑1 s‑1, and low subthreshold swing of 93 mV dec–1. Also, enhanced reliability has been achieved for the TG transistors with threshold voltage shift of 10‑3–10‑2 V MV–1 cm–1 after 6 MV cm‑1 gate-biased stressing. All improvement for the TG device can be ascribed to the formed device structure and dielectric environment. Degradation of the performance for the BG transistors should be attributed to reduced gate capacitance density and deteriorated interface properties related to vdW gap with a thickness about 0.4 nm. So, the TG transistor with MoS2 channel fully encapsulated by stacked Al2O3/HfO2 is a promising way to fabricate high-performance ML MoS2 field-effect transistors for practical electron device applications.

Performance of Transuranic-Loaded Fully Ceramic Micro-Encapsulated Fuel in LWRs Final Report, Including Void Reactivity Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael A. Pope; R. Sonat Sen; Brian Boer

2011-09-01

The current focus of the Deep Burn Project is on once-through burning of transuranics (TRU) in light-water reactors (LWRs). The fuel form is called Fully-Ceramic Micro-encapsulated (FCM) fuel, a concept that borrows the tri-isotropic (TRISO) fuel particle design from high-temperature reactor technology. In the Deep Burn LWR (DB-LWR) concept, these fuel particles are pressed into compacts using SiC matrix material and loaded into fuel pins for use in conventional LWRs. The TRU loading comes from the spent fuel of a conventional LWR after 5 years of cooling. Unit cell and assembly calculations have been performed using the DRAGON-4 code tomore » assess the physics attributes of TRU-only FCM fuel in an LWR lattice. Depletion calculations assuming an infinite lattice condition were performed with calculations of various reactivity coefficients performed at each step. Unit cells and assemblies containing typical UO2 and mixed oxide (MOX) fuel were analyzed in the same way to provide a baseline against which to compare the TRU-only FCM fuel. Then, assembly calculations were performed evaluating the performance of heterogeneous arrangements of TRU-only FCM fuel pins along with UO2 pins.« less

A Fully Integrated Quartz MEMS VHF TCXO.

PubMed

Kubena, Randall L; Stratton, Frederic P; Nguyen, Hung D; Kirby, Deborah J; Chang, David T; Joyce, Richard J; Yong, Yook-Kong; Garstecki, Jeffrey F; Cross, Matthew D; Seman, S E

2018-06-01

We report on a 32-MHz quartz temperature compensated crystal oscillator (TCXO) fully integrated with commercial CMOS electronics and vacuum packaged at wafer level using a low-temperature MEMS-after quartz process. The novel quartz resonator design provides for stress isolation from the CMOS substrate, thereby yielding classical AT-cut f/T profiles and low hysteresis which can be compensated to < ±0.2 parts per million over temperature using on-chip third-order compensation circuitry. The TCXO operates at low power of 2.5 mW and can be thinned to as part of the wafer-level eutectic encapsulation. Full integration with large state-of-the-art CMOS wafers is possible using carrier wafer techniques.

Lipid vesicles chaperone an encapsulated RNA aptamer.

PubMed

Saha, Ranajay; Verbanic, Samuel; Chen, Irene A

2018-06-13

The organization of molecules into cells is believed to have been critical for the emergence of living systems. Early protocells likely consisted of RNA functioning inside vesicles made of simple lipids. However, little is known about how encapsulation would affect the activity and folding of RNA. Here we find that confinement of the malachite green RNA aptamer inside fatty acid vesicles increases binding affinity and locally stabilizes the bound conformation of the RNA. The vesicle effectively 'chaperones' the aptamer, consistent with an excluded volume mechanism due to confinement. Protocellular organization thereby leads to a direct benefit for the RNA. Coupled with previously described mechanisms by which encapsulated RNA aids membrane growth, this effect illustrates how the membrane and RNA might cooperate for mutual benefit. Encapsulation could thus increase RNA fitness and the likelihood that functional sequences would emerge during the origin of life.

Hydrogel fibers encapsulating hiPSC-MSCs, hESC-MSCs and hUCMSCs in injectable calcium phosphate scaffold for bone tissue engineering

PubMed Central

Wang, Lin; Wang, Ping; Weir, Michael D.; Reynolds, Mark A.; Zhao, Liang; Xu, Hockin H. K.

2016-01-01

Human induced pluripotent stem cells (hiPSCs), human embryonic stem cells (hESCs) and human umbilical cord MSCs (hUCMSCs) are exciting cell sources for use in regenerative medicine. There has been no report on long hydrogel fibers encapsulating stem cells inside injectable calcium phosphate cement (CPC) scaffold for bone tissue engineering. The objectives of this study were to: (1) develop a novel injectable CPC construct containing hydrogel fibers encapsulating cells for bone engineering, and (2) investigate and compare cell viability, proliferation and osteogenic differentiation of hiPSC-MSCs, hESC-MSCs and hUCMSCs in injectable CPC. The stem cell-encapsulating pastes were fully injectable under a small injection force, and the injection did not harm the cells, compared to cells without injection (p > 0.1). Mechanical properties of stem cell-CPC construct were much higher than previous injectable polymers and hydrogels for cell delivery. hiPSC-MSCs, hESC-MSCs and hUCMSCs in hydrogel fibers in CPC had excellent proliferation and osteogenic differentiation. All three cells yielded high alkaline phosphatase, runt-related transcription factor, collagen I, and osteocalcin expressions (mean ± sd; n = 6). Cell-synthesized minerals increased substantially with time (p < 0.05), with no significant difference among the three types of cells (p > 0.1). Mineralization by hiPSC-MSCs, hESC-MSCs and hUCMSCs in CPC at 14 d was 13-fold that at 1 d. In conclusion, all three types of cells (hiPSC-MSCs, hESC-MSCs and hUCMSCs) in CPC scaffold showed high potential for bone tissue engineering, and the novel injectable CPC construct with cell-encapsulating hydrogel fibers is promising to enhance bone regeneration in dental, craniofacial and orthopedic applications. PMID:27811389

Synthesis of fullerene@gold core-shell nanostructures.

PubMed

Ren, Yupeng; Paira, Priyankar; Nayak, Tapas Ranjan; Ang, Wee Han; Pastorin, Giorgia

2011-07-21

A "direct encapsulation" method was developed for the synthesis of highly stable water-soluble fullerene@gold core-shell nanostructures, with gold nanoshells showing either closed or porous morphology. This gold nano-shell coating formed a "nano-oven", capable of decomposing encapsulated fullerene molecules rapidly when irradiated by laser. We envisaged this being a useful tool for chemical reactions as well as a novel scaffold for nano-material synthesis.

Feasibility of direct oxygenation of primary-cultured rat hepatocytes using polyethylene glycol-decorated liposome-encapsulated hemoglobin (LEH).

PubMed

Naruto, Hirosuke; Huang, Hongyun; Nishikawa, Masaki; Kojima, Nobuhiko; Mizuno, Atsushi; Ohta, Katsuji; Sakai, Yasuyuki

2007-10-01

We tested the short-term efficacy of liposome-encapsulated hemoglobin (LEH) in cultured rat hepatocytes. Supplementation with LEH (20% of the hemoglobin concentration of blood) did not lower albumin production in static culture, and completely reversed the cell death and deterioration in albumin production caused by an oxygen shortage in 2D flat-plate perfusion bioreactors.

Encapsulated cell bioremediation: Evaluation on the basis of particle tracer tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrich, C.R.; Stormo, K.E.; Ralston, D.R.

1998-09-01

Microencapsulation of degradative organisms enhances microorganism survivability. The use of encapsulated cell microbeads for in situ biodegradation depends not only on microorganism survival but also on microbead transport characteristics. Two forced-gradient, recirculating-loop tracer experiments were conducted to evaluate the feasibility of encapsulated cell transport and bioremediation on the basis of polystyrene microsphere transport results. The tracer tests were conducted in a shallow, confined, unconsolidated, heterogeneous, sedimentary aquifer using bromide ion and 2 {micro}m, 5 {micro}m, and 15{micro}m microsphere tracers. Significant differences were observed in the transport of bromide solute and polystyrene microspheres. Microspheres reached peak concentrations in monitoring wells beforemore » bromide, which was thought to reflect the influence of aquifer heterogeneity. Greater decreases in microsphere C/C{sub 0} ratios were observed with distance from the injection wells than in bromide C/C{sub 0} ratios, which was attributed to particle filtration and/or settling. Several methods might be considered for introducing encapsulated cell microbeads into a subsurface environment, including direct injection into a contaminated aquifer zone, injection through a recirculating ground water flow system, or emplacement in a subsurface microbial curtain in advance of a plume. However, the in situ use of encapsulated cells in an aquifer is probably limited to aquifers containing sufficiently large pore spaces, allowing passage of at least some encapsulated cells. The use of encapsulated cells may also be limited by differences in solute and microbead transport patterns and flowpath clogging by larger encapsulated cell microbeads.« less

Shaping up synthetic cells

NASA Astrophysics Data System (ADS)

Mulla, Yuval; Aufderhorst-Roberts, Anders; Koenderink, Gijsje H.

2018-07-01

How do the cells in our body reconfigure their shape to achieve complex tasks like migration and mitosis, yet maintain their shape in response to forces exerted by, for instance, blood flow and muscle action? Cell shape control is defined by a delicate mechanical balance between active force generation and passive material properties of the plasma membrane and the cytoskeleton. The cytoskeleton forms a space-spanning fibrous network comprising three subsystems: actin, microtubules and intermediate filaments. Bottom-up reconstitution of minimal synthetic cells where these cytoskeletal subsystems are encapsulated inside a lipid vesicle provides a powerful avenue to dissect the force balance that governs cell shape control. Although encapsulation is technically demanding, a steady stream of advances in this technique has made the reconstitution of shape-changing minimal cells increasingly feasible. In this topical review we provide a route-map of the recent advances in cytoskeletal encapsulation techniques and outline recent reports that demonstrate shape change phenomena in simple biomimetic vesicle systems. We end with an outlook toward the next steps required to achieve more complex shape changes with the ultimate aim of building a fully functional synthetic cell with the capability to autonomously grow, divide and move.

Natural History of Gas Configurations and Encapsulation in Necrotic Collections During Necrotizing Pancreatitis.

PubMed

van Grinsven, Janneke; van Brunschot, Sandra; van Baal, Mark C; Besselink, Marc G; Fockens, Paul; van Goor, Harry; van Santvoort, Hjalmar C; Bollen, Thomas L

2018-05-11

Decision-making on invasive intervention in patients with clinical signs of infected necrotizing pancreatitis is often related to the presence of gas configurations and the degree of encapsulation in necrotic collections on imaging. Data on the natural history of gas configurations and encapsulation in necrotizing pancreatitis are, however, lacking. A post hoc analysis was performed of a previously described prospective cohort in 21 Dutch hospitals (2004-2008). All computed tomography scans (CTs) performed during hospitalization for necrotizing pancreatitis were categorized per week (1 to 8, and thereafter) and re-assessed by an abdominal radiologist. A total of 639 patients with necrotizing pancreatitis were included, with median four (IQR 2-7) CTs per patient. The incidence of first onset of gas configurations varied per week without a linear correlation: 2-3-13-11-10-19-12-21-12%, respectively. Overall, gas configurations were found in 113/639 (18%) patients and in 113/202 (56%) patients with infected necrosis. The incidence of walled-off necrosis increased per week: 0-3-12-39-62-76-93-97-100% for weeks 1-8 and thereafter respectively. Clinically relevant walled-off necrosis (largely or fully encapsulated necrotic collections) was seen in 162/379 (43%) patients within the first 3 weeks. Gas configurations occur in every phase of the disease and develop in half of the patients with infected necrotizing pancreatitis. Opposed to traditional views, clinically relevant walled-off necrosis occurs frequently within the first 3 weeks.

Microencapsulated Bioactive Agents and Method of Making

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

2003-01-01

The invention is directed to microcapsules encapsulating an aqueous solution of a protein, drug or other bioactive substance inside a semi-permeable membrane. The microcapsules are formed by interfacial coacervation where shear forces are limited to 0-100 dynes per square centimeter. The resulting uniform microcapsules can then be subjected to dewatering in order to cause the internal solution to become supersaturated with the dissolved substance. This dewatering allows controlled nucleation and crystallization of the dissolved substance. The crystal-filled microcapsules can be stored, keeping the encapsulated crystals in good condition for further direct use in x-ray crystallography or as injectable formulations of the dissolved drug, protein or other bioactive substance.

Photobiomodulation of mesenchymal stem cells encapsulated in an injectable rhBMP4-loaded hydrogel directs hard tissue bioengineering.

PubMed

Diniz, Ivana M A; Carreira, Ana C O; Sipert, Carla R; Uehara, Cindi M; Moreira, Maria S N; Freire, Laila; Pelissari, Cibele; Kossugue, Patrícia M; de Araújo, Daniele R; Sogayar, Mari C; Marques, Márcia M

2018-06-01

Photobiomodulation (PBM) therapy displays relevant properties for tissue healing and regeneration, which may be of interest for the tissue engineering field. Here, we show that PBM is able to improve cell survival and to interact with recombinant human Bone Morphogenetic Protein 4 (rhBMP4) to direct and accelerate odonto/osteogenic differentiation of dental derived mesenchymal stem cells (MSCs). MSCs were encapsulated in an injectable and thermo-responsive cell carrier (Pluronic ® F-127) loaded with rhBMP4 and then photoactivated. PBM improved MSCs self-renewal and survival upon encapsulation in the Pluronic ® F-127. In the presence of rhBMP4, cell odonto/osteogenic differentiation was premature and markedly improved in the photoactivated MSCs. An in vivo calvarial critical sized defect model demonstrated significant increase in bone formation after PBM treatment. Finally, a balance in the reactive oxygen species levels may be related to the favorable results of PBM and rhBMP4 association. PBM may act in synergism with rhBMP4 and is a promise candidate to direct and accelerate hard tissue bioengineering. © 2017 Wiley Periodicals, Inc.

A paramagnetic implant containing lithium naphthalocyanine microcrystals for high-resolution biological oximetry

PubMed Central

Meenakshisundaram, Guruguhan; Pandian, Ramasamy P.; Eteshola, Edward; Lee, Stephen C.; Kuppusamy, Periannan

2009-01-01

Lithium naphthalocyanine (LiNc) is a microcrystalline EPR oximetry probe with high sensitivity to oxygen (Pandian et al. J. Mater. Chem., 19, 4138, 2009). However, direct implantation of the crystals in the tissue for in vivo oxygen measurements may be hindered by concerns associated with their direct contact with the tissue/cells and loss of EPR signal due to particle migration in the tissue. In order to address these concerns, we have developed encapsulations (chips) of LiNc microcrystals in polydimethyl siloxane (PDMS), an oxygen-permeable, bioinert polymer. Oximetry evaluation of the fabricated chips revealed that the oxygen sensitivity of the crystals was unaffected by encapsulation in PDMS. Chips were stable against sterilization procedures or treatment with common biological oxidoreductants. In vivo oxygen measurements established the ability of the chips to provide reliable and repeated measurements of tissue oxygenation. This study establishes PDMS-encapsulated LiNc as a potential probe for long-term and repeated measurements of tissue oxygenation. PMID:20006529

Encapsulation of Polymer Colloids in a Sol-Gel Matrix. Direct-Writing of Coassembling Organic-Inorganic Hybrid Photonic Crystals.

PubMed

Mikosch, Annabel; Kuehne, Alexander J C

2016-03-22

The spontaneous self-assembly of polymer colloids into ordered arrangements provides a facile strategy for the creation of photonic crystals. However, these structures often suffer from defects and insufficient cohesion, which result in flaking and delamination from the substrate. A coassembly process has been developed for convective assembly, resulting in large-area encapsulated colloidal crystals. However, to generate patterns or discrete deposits in designated places, convective assembly is not suitable. Here we experimentally develop conditions for direct-writing of coassembling monodisperse dye-doped polystyrene particles with a sol-gel precursor to form solid encapsulated photonic crystals. In a simple procedure the colloids are formulated in a sol-gel precursor solution, drop-cast on a flat substrate, and dried. We here establish the optimal parameters to form reproducible highly ordered photonic crystals with good optical performance. The obtained photonic crystals interact with light in the visible spectrum with a narrow optical stop-gap.

Effects of Chromium Dopant on Ultraviolet Photoresponsivity of ZnO Nanorods

NASA Astrophysics Data System (ADS)

Mokhtari, S.; Safa, S.; Khayatian, A.; Azimirad, R.

2017-07-01

Structural and optical properties of bare ZnO nanorods, ZnO-encapsulated ZnO nanorods, and Cr-doped ZnO-encapsulated ZnO nanorods have been investigated. Encapsulated ZnO nanorods were grown using a simple two-stage method in which ZnO nanorods were first grown on a glass substrate directly from a hydrothermal bath, then encapsulated with a thin layer of Cr-doped ZnO by dip coating. Comparative study of x-ray diffraction patterns showed that Cr was successfully incorporated into the shell layer of ZnO nanorods. Moreover, energy-dispersive x-ray spectroscopy confirmed presence of Cr in this sample. It was observed that the thickness of the shell layer around the core of the ZnO nanorods was at least about 20 nm. Transmission electron microscopy of bare ZnO nanorods revealed single-crystalline structure. Based on optical results, both the encapsulation process and addition of Cr dopant decreased the optical bandgap of the samples. Indeed, the optical bandgap values of Cr-doped ZnO-encapsulated ZnO nanorods, ZnO-encapsulated ZnO nanorods, and bare ZnO nanorods were 2.89 eV, 3.15 eV, and 3.34 eV, respectively. The ultraviolet (UV) parameters demonstrated that incorporation of Cr dopant into the shell layer of ZnO nanorods considerably facilitated formation and transportation of photogenerated carriers, optimizing their performance as a practical UV detector. As a result, the photocurrent of the Cr-doped ZnO-encapsulated ZnO nanorods was the highest (0.6 mA), compared with ZnO-encapsulated ZnO nanorods and bare ZnO nanorods (0.21 mA and 0.06 mA, respectively).

Hybrid bone implants: self-assembly of peptide amphiphile nanofibers within porous titanium.

PubMed

Sargeant, Timothy D; Guler, Mustafa O; Oppenheimer, Scott M; Mata, Alvaro; Satcher, Robert L; Dunand, David C; Stupp, Samuel I

2008-01-01

Over the past few decades there has been great interest in the use of orthopedic and dental implants that integrate into tissue by promoting bone ingrowth or bone adhesion, thereby eliminating the need for cement fixation. However, strategies to create bioactive implant surfaces to direct cellular activity and mineralization leading to osteointegration are lacking. We report here on a method to prepare a hybrid bone implant material consisting of a Ti-6Al-4V foam, whose 52% porosity is filled with a peptide amphiphile (PA) nanofiber matrix. These PA nanofibers can be highly bioactive by molecular design, and are used here as a strategy to transform an inert titanium foam into a potentially bioactive implant. Using scanning electron microscopy (SEM) and confocal microscopy, we show that PA molecules self-assemble into a nanofiber matrix within the pores of the metallic foam, fully occupying the foam's interconnected porosity. Furthermore, the method allows the encapsulation of cells within the bioactive matrix, and under appropriate conditions the nanofibers can nucleate mineralization of calcium phosphate phases with a Ca:P ratio that corresponds to that of hydroxyapatite. Cell encapsulation was quantified using a DNA measuring assay and qualitatively verified by SEM and confocal microscopy. An in vivo experiment was performed using a bone plug model in the diaphysis of the hind femurs of a Sprague Dawley rat and examined by histology to evaluate the performance of these hybrid systems after 4 weeks of implantation. Preliminary results demonstrate de novo bone formation around and inside the implant, vascularization around the implant, as well as the absence of a cytotoxic response. The PA-Ti hybrid strategy could be potentially tailored to initiate mineralization and direct a cellular response from the host tissue into porous implants to form new bone and thereby improve fixation, osteointegration, and long term stability of implants.

Proof-of-Concept of a Revolutionary Cooling Shirt with a Thermal Manikin

DTIC Science & Technology

2013-09-01

involving high levels of physical activity or exposure to high temperature environments including military, fire protection, and sports . Battlefield...spandex. Pockets of the same material were created to fully encapsulate the lightweight cryotherapy pad. The cooling medium is flame resistant to 815°C...effect on the manikin. Per manufacturer recommendation, the cryotherapy pads were stored in a refrigerator at 10°C to obtain a maximum effect. New pads

Improving Joint Function Using Photochemical Hydrogels for Articular Surface Repair

DTIC Science & Technology

2012-10-01

with thrombin previously has been reported as a favorable scaffold for cartilage formation by encapsulated chondrocytes [10]. Studies over the past...during the photochemical crosslinking process. A full scale study is planned for the first quarter of year 3 to evaluate the fully formed cartilage ...Perform initial study of collagen and PEG gels with stem cells implanted in mice  Bone marrow MSCs were harvested from donor swine and grown in culture

Development of alginate microspheres containing thyme essential oil using ionic gelation.

PubMed

Benavides, Sergio; Cortés, Pablo; Parada, Javier; Franco, Wendy

2016-08-01

Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000rpm/5min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modification of Encapsulation Pressure of Reverse Micelles in Liquid Ethane

PubMed Central

Peterson, Ronald W.; Nucci, Nathaniel V.; Wand, A. Joshua

2011-01-01

Encapsulation of within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5,000 p.s.i. to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described. PMID:21764613

Modification of encapsulation pressure of reverse micelles in liquid ethane.

PubMed

Peterson, Ronald W; Nucci, Nathaniel V; Wand, A Joshua

2011-09-01

Encapsulation within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5000 psi to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described. Copyright © 2011 Elsevier Inc. All rights reserved.

Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auricchio, N.; Caroli, E.; Marchini, L.

2011-12-15

Presently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing largermore » single grains with a lower dislocation density to be obtained. Several mono-electrode detectors were realized, with each having two planar gold contacts. The samples are characterized by an active area of about 7 mm x 7 mm and thicknesses ranging from 1 to 2 mm. The charge transport properties of the detectors have been studied by mobility-lifetime ({mu} x {tau}) product measurements, carried out at the European Synchrotron Radiation Facility (Grenoble, France) in the planar transverse field configuration, where the impinging beam direction is orthogonal to the collecting electric field. We have performed several fine scans between the electrodes with a beam spot of 10 {mu}m x 10 {mu}m at various energies from 60 to 400 keV. In this work, we present the test results in terms of the ({mu} x {tau}) product of both charge carriers.« less

Encapsulation of a rhodamine dye within a bile acid binding protein: toward water processable functional bio host-guest materials.

PubMed

Tomaselli, Simona; Giovanella, Umberto; Pagano, Katiuscia; Leone, Giuseppe; Zanzoni, Serena; Assfalg, Michael; Meinardi, Francesco; Molinari, Henriette; Botta, Chiara; Ragona, Laura

2013-10-14

New strategies are requested for the preparation of bioinspired host-guest complexes to be employed in technologically relevant applications, as sensors and optoelectronic devices. We report here a new approach employing a single monomeric protein as host for the strongly fluorescent rhodamine dye. The selected protein, belonging to the intracellular lipid binding protein family, fully encapsulates one rhodamine molecule inside its cavity forming a host-guest complex stabilized by H and π-hydrogen bonds, a salt bridge, and favorable hydrophobic contacts, as revealed by the NMR derived structural model. The protein-dye solutions are easily processable and form homogeneous thin films exhibiting excellent photophysical and morphological properties, as derived from photoluminescence and AFM data. The obtained results represent the proof of concept of the viability of this bio host-guest system for the development of bioinspired optoelectronic devices.

Self-Assembly of a Tripodal Triszwitterion Forms a pH-Switchable Hydrogel that Can Reversibly Encapsulate Hydrophobic Guests in Water.

PubMed

Jana, Poulami; Schmuck, Carsten

2017-01-05

The development of supramolecular smart materials, which exhibit physicochemical structural changes in response to external stimuli is of current interest for various applications. Herein, we have developed the novel tripodal triszwitterion 1, derived from a C 3 -symmetric benzene-1,3,5-tricarboxamide (BTA) core, which forms a thermo-reversible and pH-switchable transparent hydrogel through intermolecular self-complementary zwitterionic interactions at a neutral pH value. The hierarchical supramolecular self-aggregation was fully analyzed by microscopy (AFM, field emission scanning electron microscopy (FESEM)), viscosity, dynamic light scattering (DLS), and rheology studies. Moreover, compound 1 enables to encapsulate hydrophobic guests, such as the dye Nile red in aqueous medium at pH 6, which makes it an interesting candidate for drug delivery and controlled release. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of Cu(In,Ga)Se2 Test Coupons for Potential Induced Degradation Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Contreras, Miguel A.; Hacke, Peter; Repins, Ingrid

We report on the design, fabrication and accelerated testing of fully encapsulated small area coupons (approximately 7.5cm x 7.5 cm) for the purpose of researching potential induced degradation in Cu(In, Ga)Se2 based PV modules. The fabrication of these coupons enables the study of the solar cells and the materials used in PV module manufacturing such as top and bottom glass covers of different composition (soda-lime glass, high temperature glass, alkaline-free glass, etc), plastic-based top covers, ethylene vinyl acetate and edge seal encapsulation materials. The coupons can also be used to emulate framed and frameless modules that utilize either monolithically interconnectedmore » modules or singular cell type of modules. The design of the coupons, their fabrication, the materials used and their testing for 1000 hours under 85 degrees C and 85% RH conditions are presented.« less

Synthesis and characterization of hollow magnetic nanospheres modified with Au nanoparticles for bio-encapsulation

NASA Astrophysics Data System (ADS)

Seisno, Satoshi; Suga, Kent; Nakagawa, Takashi; Yamamoto, Takao A.

2017-04-01

Hollow magnetic nanospheres modified with Au nanoparticles were successfully synthesized. Au/SiO2 nanospheres fabricated by a radiochemical process were used as templates for ferrite templating. After the ferrite plating process, Au/SiO2 templates were fully coated with magnetite nanoparticles. Dissolution of the SiO2 core lead to the formation of hollow magnetic nanospheres with Au nanoparticles inside. The hollow magnetic nanospheres consisted of Fe3O4 grains, with an average diameter of 60 nm, connected to form the sphere wall, inside which Au grains with an average diameter of 7.2 nm were encapsulated. The Au nanoparticles immobilized on the SiO2 templates contributed to the adsorption of the Fe ion precursor and/or Fe3O4 seeds. These hollow magnetic nanospheres are proposed as a new type of nanocarrier, as the Au grains could specifically immobilize biomolecules inside the hollow sphere.

Analysis and experimental study on the strain transfer mechanism of an embedded basalt fiber-encapsulated fiber Bragg grating sensor

NASA Astrophysics Data System (ADS)

Zhang, Zhenglin; Wang, Yuan; Sun, Yangyang; Zhang, Qinghua; You, Zewei; Huang, Xiaodi

2017-01-01

The precision of the encapsulated fiber optic sensor embedded into a host suffers from the influences of encapsulating materials. Furthermore, an interface transfer effect of strain sensing exists. This study uses an embedded basalt fiber-encapsulated fiber Bragg grating (FBG) sensor as the research object to derive an expression in a multilayer interface strain transfer coefficient by considering the mechanical properties of the host material. The direct impact of the host material on the strain transfer at an embedded multipoint continuous FBG (i.e., multiple gratings written on a single optical fiber) monitoring strain sensor, which was self-developed and encapsulated with basalt fiber, is studied to present the strain transfer coefficients corresponding to the positions of various gratings. The strain transfer coefficients of the sensor are analyzed based on the experiments designed for this study. The error of the experimental results is ˜2 μɛ when the strain is at 60 μɛ and below. Moreover, the measured curves almost completely coincide with the theoretical curves. The changes in the internal strain field inside the embedded structure of the basalt fiber-encapsulated FBG strain sensor could be easily monitored. Hence, important references are provided to measure the internal stress strain of the sensor.

Handbook of photothermal test data on encapsulant materials

NASA Astrophysics Data System (ADS)

Liang, R. H.; Oda, K. L.; Chung, S. Y.; Smith, M. V.; Gupta, A.

1983-05-01

Laboratory tests performed to characterize candidate encapsulation materials with respect to changes in their physical and chemical properties caused by photothermal aging are described. Several key material properties relating directly to material degradation and deterioration of performance were identified and were monitored as functions of aging conditions and time. A status report on accelerated testing activities is provided and experimental data are presented. It will be updated periodically as more data become available.

Handbook of photothermal test data on encapsulant materials

NASA Technical Reports Server (NTRS)

Liang, R. H.; Oda, K. L.; Chung, S. Y.; Smith, M. V.; Gupta, A.

1983-01-01

Laboratory tests performed to characterize candidate encapsulation materials with respect to changes in their physical and chemical properties caused by photothermal aging are described. Several key material properties relating directly to material degradation and deterioration of performance were identified and were monitored as functions of aging conditions and time. A status report on accelerated testing activities is provided and experimental data are presented. It will be updated periodically as more data become available.

A Wireless Fully Passive Neural Recording Device for Unobtrusive Neuropotential Monitoring.

PubMed

Kiourti, Asimina; Lee, Cedric W L; Chae, Junseok; Volakis, John L

2016-01-01

We propose a novel wireless fully passive neural recording device for unobtrusive neuropotential monitoring. Previous work demonstrated the feasibility of monitoring emulated brain signals in a wireless fully passive manner. In this paper, we propose a novel realistic recorder that is significantly smaller and much more sensitive. The proposed recorder utilizes a highly efficient microwave backscattering method and operates without any formal power supply or regulating elements. Also, no intracranial wires or cables are required. In-vitro testing is performed inside a four-layer head phantom (skin, bone, gray matter, and white matter). Compared to our former implementation, the neural recorder proposed in this study has the following improved features: 1) 59% smaller footprint, 2) up to 20-dB improvement in neuropotential detection sensitivity, and 3) encapsulation in biocompatible polymer. For the first time, temporal emulated neuropotentials as low as 63 μVpp can be detected in a wireless fully passive manner. Remarkably, the high-sensitivity achieved in this study implies reading of most neural signals generated by the human brain. The proposed recorder brings forward transformational possibilities in wireless fully passive neural detection for a very wide range of applications (e.g., epilepsy, Alzheimer's, mental disorders, etc.).

Effects of surgically implanted transmitters on reproduction and survival in mallards

USGS Publications Warehouse

Sheppard, Jennifer; Arnold, Todd W.; Amundson, Courtney L.; Klee, David

2017-01-01

Abdominally implanted radiotransmitters have been widely used in studies of waterbird ecology; however, the longer handling times and invasiveness of surgical implantation raise important concerns about animal welfare and potential effects on data quality. Although it is difficult to assess effects of handling and marking wild animals by comparing them with unmarked controls, insights can often be obtained by evaluating variation in handling or marking techniques. Here, we used data from 243 female mallards (Anas platyrhynchos) and mallard–grey duck hybrids (A. platyrhynchos × A. superciliosa) equipped with fully encapsulated abdominally implanted radiotransmitters from 2 study sites in New Zealand during 2014–2015 to assess potential marking effects. We evaluated survival, dispersal, and reproductive effort (e.g., breeding propensity, nest initiation date, clutch size) in response to 3 different attributes of handling duration and procedures: 1) processing time, including presurgery banding, measurements, and blood sampling of unanaesthetized birds; 2) surgery time from initiation to cessation of anesthetic; and 3) total holding time from first capture until release. We found no evidence that female survival, dispersal probability, or reproductive effort were negatively affected by holding, processing, or surgery time and concluded that we collected reliable data without compromising animal welfare. Our results support previous research that techniques using fully encapsulated abdominal-implant radiotransmitters are suitable to enable researchers to obtain reliable estimates of reproductive performance and survival. 

Protection of xenografts by a combination of immunoisolation and a single dose of anti-CD4 antibody.

PubMed

Mckenzie, A W; Georgiou, H M; Zhan, Y; Brady, J L; Lew, A M

2001-01-01

Immunoisolation is the separation of transplanted cells from cells of the immune system using a semipermeable membrane. Using one such immunoisolation capsule-the TheraCyte device-we have assessed the survival of encapsulated xenogeneic tissue in vivo as well as the contribution of CD4+ve T cells to encapsulated xenograft rejection. The foreign body reaction to the TheraCyte capsule in vivo was assessed by transplanting empty capsules into normal mice. These capsules elicit a foreign body response by the host animal. Encapsulated CHO, NIT-1, and PK-15 cells were placed in culture and in immunodeficient mice to investigate their growth characteristics in the TheraCyte device. These cell lines survive both in culture and in immunodeficient SCID mice. Xenogeneic PK cells were also transplanted into normal C57BL/6 mice. These cells do not survive in normal mice despite the absence of direct contact between infiltrating and encapsulated cells. In addition, the survival of encapsulated cells in mice treated with a single dose of anti-CD4 antibody was examined. This was assessed using two systems: 1) histological analysis of capsule sections; 2) a quantitative luciferase reporter system using PK cells transfected to express luciferase. In both cases, anti-CD4 antibody contributed to prolonged encapsulated xenogeneic cell survival. Encapsulated xenogeneic cells survive in immunodeficient mice but not normal mice. Treatment of normal mice with anti-CD4 antibody results in prolonged survival of xenogeneic cells that can be measured using a luciferase reporter system. These results highlight the contribution of CD4+ve T cells to encapsulated xenograft rejection.

Fabrication of hemispherical liquid encapsulated structures based on droplet molding

NASA Astrophysics Data System (ADS)

Ishizuka, Hiroki; Miki, Norihisa

2015-12-01

We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

Developing a tissue-engineered neural-electrical relay using encapsulated neuronal constructs on conducting polymer fibers.

PubMed

Cullen, D Kacy; R Patel, Ankur; Doorish, John F; Smith, Douglas H; Pfister, Bryan J

2008-12-01

Neural-electrical interface platforms are being developed to extracellularly monitor neuronal population activity. Polyaniline-based electrically conducting polymer fibers are attractive substrates for sustained functional interfaces with neurons due to their flexibility, tailored geometry and controlled electro-conductive properties. In this study, we addressed the neurobiological considerations of utilizing small diameter (<400 microm) fibers consisting of a blend of electrically conductive polyaniline and polypropylene (PA-PP) as the backbone of encapsulated tissue-engineered neural-electrical relays. We devised new approaches to promote survival, adhesion and neurite outgrowth of primary dorsal root ganglion neurons on PA-PP fibers. We attained a greater than ten-fold increase in the density of viable neurons on fiber surfaces to approximately 700 neurons mm(-2) by manipulating surrounding surface charges to bias settling neuronal suspensions toward fibers coated with cell-adhesive ligands. This stark increase in neuronal density resulted in robust neuritic extension and network formation directly along the fibers. Additionally, we encapsulated these neuronal networks on PA-PP fibers using agarose to form a protective barrier while potentially facilitating network stability. Following encapsulation, the neuronal networks maintained integrity, high viability (>85%) and intimate adhesion to PA-PP fibers. These efforts accomplished key prerequisites for the establishment of functional electrical interfaces with neuronal populations using small diameter PA-PP fibers-specifically, improved neurocompatibility, high-density neuronal adhesion and neuritic network development directly on fiber surfaces.

3D Bioprinting of Heterogeneous Aortic Valve Conduits with Alginate/Gelatin Hydrogels

PubMed Central

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

2013-01-01

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 when printed in stiff matrix, while VIC expressed elevated vimentin in soft matrix. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting. PMID:23015540

Highly Stable, Dual-Gated MoS2 Transistors Encapsulated by Hexagonal Boron Nitride with Gate-Controllable Contact, Resistance, and Threshold Voltage.

PubMed

Lee, Gwan-Hyoung; Cui, Xu; Kim, Young Duck; Arefe, Ghidewon; Zhang, Xian; Lee, Chul-Ho; Ye, Fan; Watanabe, Kenji; Taniguchi, Takashi; Kim, Philip; Hone, James

2015-07-28

Emerging two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS2) have been intensively studied because of their novel properties for advanced electronics and optoelectronics. However, 2D materials are by nature sensitive to environmental influences, such as temperature, humidity, adsorbates, and trapped charges in neighboring dielectrics. Therefore, it is crucial to develop device architectures that provide both high performance and long-term stability. Here we report high performance of dual-gated van der Waals (vdW) heterostructure devices in which MoS2 layers are fully encapsulated by hexagonal boron nitride (hBN) and contacts are formed using graphene. The hBN-encapsulation provides excellent protection from environmental factors, resulting in highly stable device performance, even at elevated temperatures. Our measurements also reveal high-quality electrical contacts and reduced hysteresis, leading to high two-terminal carrier mobility (33-151 cm(2) V(-1) s(-1)) and low subthreshold swing (80 mV/dec) at room temperature. Furthermore, adjustment of graphene Fermi level and use of dual gates enable us to separately control contact resistance and threshold voltage. This novel vdW heterostructure device opens up a new way toward fabrication of stable, high-performance devices based on 2D materials.

L-Asparaginase encapsulated intact erythrocytes for treatment of acute lymphoblastic leukemia (ALL).

PubMed

Kwon, Young Min; Chung, Hee Sun; Moon, Cheol; Yockman, James; Park, Yoon Jeong; Gitlin, Scott D; David, Allan E; Yang, Victor C

2009-11-03

As a primary drug for the treatment of acute lymphoblastic leukemia (ALL), encapsulation of L-asparaginase (ASNase) into red blood cells (RBC) has been popular to circumvent immunogenicity from the exogenous protein. Unlike existing methods that perturbs RBC membranes, we introduce a novel method of RBC-incorporation of proteins using the membrane-translocating low molecular weight protamine (LMWP). Confocal study of fluorescence-labeled LMWP-ovalbumin, as a model protein conjugate, has shown significant fluorescence inside RBCs. Surface morphology by scanning electron microscopy of the RBCs loaded with LMWP-ASNase was indistinguishable with normal RBCs. These drug loaded RBCs also closely resembled the profile of the native erythrocytes in terms of osmotic fragility, oxygen dissociation and hematological parameters. The in vivo half-life of enzyme activity after administering 8 units of RBC/LMWP-ASNase in DBA/2 mice was prolonged to 4.5+/-0.5 days whereas that of RBCs loaded with ASNase via a hypotonic method was 2.4+/-0.7 days. Furthermore, the mean survival time of DBA/2 mice bearing mouse lymphoma cell L5178Y was improved by approximately 44% compared to the saline control group after treatment with the RBC loaded enzymes. From these data, an innovative, novel method for encapsulating proteins into intact and fully functional erythrocytes was established for potential treatment of ALL.

Microbial characterization of the Mars Odyssey spacecraft and its encapsulation facility.

PubMed

La Duc, Myron T; Nicholson, Wayne; Kern, Roger; Venkateswaran, Kasthuri

2003-10-01

Microbial characterization of the Mars Odyssey spacecraft and the Kennedy Space Center Spacecraft Assembly and Encapsulation Facility II (SAEF-II) was carried out by both culture-based and molecular methods. The most dominant cultivable microbes were species of Bacillus, with comamonads, microbacteria and actinomycetales also represented. Several spore-forming isolates were resistant to gamma-radiation, UV, H2O2 and desiccation, and one Acinetobacter radioresistens isolate and several Aureobasidium, isolated directly from the spacecraft, survived various conditions. Sequences arising in clone libraries were fairly consistent between the spacecraft and facility; predominant genera included Variovorax, Ralstonia and Aquaspirillum. This study improves our understanding of the microbial community structure, diversity and survival capabilities of microbes in an encapsulation facility and physically associated with colocated spacecraft.

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE PAGES

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.; ...

2017-04-26

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Microbial characterization of the Mars Odyssey spacecraft and its encapsulation facility

NASA Technical Reports Server (NTRS)

La Duc, Myron T.; Nicholson, Wayne; Kern, Roger; Venkateswaran, Kasthuri

2003-01-01

Microbial characterization of the Mars Odyssey spacecraft and the Kennedy Space Center Spacecraft Assembly and Encapsulation Facility II (SAEF-II) was carried out by both culture-based and molecular methods. The most dominant cultivable microbes were species of Bacillus, with comamonads, microbacteria and actinomycetales also represented. Several spore-forming isolates were resistant to gamma-radiation, UV, H2O2 and desiccation, and one Acinetobacter radioresistens isolate and several Aureobasidium, isolated directly from the spacecraft, survived various conditions. Sequences arising in clone libraries were fairly consistent between the spacecraft and facility; predominant genera included Variovorax, Ralstonia and Aquaspirillum. This study improves our understanding of the microbial community structure, diversity and survival capabilities of microbes in an encapsulation facility and physically associated with colocated spacecraft.

Investigation of Test Methods, Material Properties, and Processes for Solar Cell Encapsulents

NASA Technical Reports Server (NTRS)

1978-01-01

The technical activities were directed toward the assessment of encapsulation processes for use with ethylene/vinyl acetate copolymer as the pottant. Potentially successful formulations were prepared by compounding the raw polymer with ultraviolet absorbers and crosslinking agents to give stabilized and curable compositions. The compounded resin was then converted to a more useful form with an extruder to give pottant in sheets that could be more easily used in lamination. After experimenting with various techniques, the vacuum-bag process was found to be an excellent encapsulation method. Miniature single-celled and multi-celled solar modules of both substrate and superstrate designs were prepared by this technique. The resulting modules were of good appearance, were bubble-free, and successfully passed the thermal cycle test.

Preparation and Efficacy of a Live Newcastle Disease Virus Vaccine Encapsulated in Chitosan Nanoparticles

PubMed Central

Gao, Ting-ting; Li, Wei; Zhao, Yan; Zhang, Feng-qiang; Wu, Jin; Cui, Xianlan; Wang, Yun-Feng

2012-01-01

Background Newcastle disease (ND) is a highly contagious viral disease of poultry caused by pathogenic strains of the Newcastle disease virus (NDV). Live NDV vaccines are administered by drinking water, eyedrops or coarse aerosol spray. To further enhance mucosal immune responses, chitosan nanoparticles were developed for the mucosal delivery of a live NDV vaccine. Methodology/Principal Findings A lentogenic live-virus vaccine (strain LaSota) against NDV encapsulated in chitosan nanoparticles were developed using an ionic crosslinking method. Chitosan nanoparticles containing the lentogenic live-virus vaccine against NDV (NDV-CS-NPs) were produced with good morphology, high stability, a mean diameter of 371.1 nm, an encapsulation rate of 77% and a zeta potential of +2.84 mV. The Western blotting analysis showed that NDV structural proteins were detected in NDV-CS-NPs. The virus release assay results of NDV-CS-NPs indicated that NDV was released from NDV-CS-NPs. Chickens immunized orally or intranasally with NDV-CS-NPs were fully protected whereas one out of five chickens immunized with the LaSota live NDV vaccine and three out of five chickens immunized with the inactivated NDV vaccine were dead after challenge with the highly virulent NDV strain F48E9. Conclusions/Significance NDV-CS-NPs induced better protection of immunized specific pathogen free chickens compared to the live NDV vaccine strain LaSota and the inactivated NDV vaccine. This study lays a foundation for the further development of mucosal vaccines and drugs encapsulated in chitosan nanoparticles. PMID:23285276

Chemiresistive hydrogen gas sensors from gold-palladium nanopeapods

NASA Astrophysics Data System (ADS)

Moon, Chung Hee; Myung, Nosang V.; Haberer, Elaine D.

2014-12-01

Gold-palladium (Au-Pd) nanopeapod-based H2 chemiresistors were fabricated using a gold binding M13 viral template. Peptides displayed along the length of this biological template served as affinity binding sites to direct gold nanoparticle assembly under ambient conditions in an aqueous environment. In addition, the geometry of this filamentous biomolecule readily facilitated the formation of the highly anisotropic nanopeapod structure. Pd electroless deposition controlled peapod diameter, as well as electrical resistance. Sensor performance was determined by overall peapod morphology. Thicker nanopeapods (i.e., ˜15 nm Pd layer) with fully encapsulated Au nanoparticle seeds showed strong evidence of oxygen inclusion during or after Pd deposition, and a modest response (i.e., 0.04%-2.6%) at 2000 ppmv H2 after device conditioning through extended H2 exposure. Thinner nanopeapods (i.e., ˜5 nm Pd layer) with discontinuous Au nanoparticle coverage showed superior performance with a response of 117% at 2000 ppmv H2 in air, a 70% response time (t70%) within 1 min, and a low detection limit of 25 ppmv. The bio-directed formation of these unique thin-shelled, Au-Pd peapod nanostructures and the development of a highly sensitive H2 detector advance both the fields of nanoassembly and gas sensing.

Squaraine rotaxanes with boat conformation macrocycles.

PubMed

Fu, Na; Baumes, Jeffrey M; Arunkumar, Easwaran; Noll, Bruce C; Smith, Bradley D

2009-09-04

Mechanical encapsulation of fluorescent, deep-red bis(anilino)squaraine dyes inside Leigh-type tetralactam macrocycles produces interlocked squaraine rotaxanes. The surrounding macrocycles are flexible and undergo rapid exchange of chair and boat conformations in solution. A series of X-ray crystal structures show how the rotaxane co-conformational exchange process involves simultaneous lateral oscillation of the macrocycle about the center of the encapsulated squaraine thread. Rotaxane macrocycles with 1,4-phenylene sidewalls and 2,6-pyridine dicarboxamide bridging units are more likely to adopt boat conformations in the solid state than analogous squaraine rotaxane systems with isophthalamide-containing macrocycles. A truncated squaraine dye, with a secondary amine attached directly to the central C(4)O(2) core, is less electrophilic than the extended bis(anilino)squaraine analogue, but it is still susceptible to chemical and photochemical bleaching. Its stability is greatly enhanced when it is encapsulated as an interlocked squaraine rotaxane. An X-ray crystal structure of this truncated squaraine rotaxane shows the macrocycle in a boat conformation, and NMR studies indicate that the boat is maintained in solution. Encapsulation as a rotaxane increases the dye's brightness by a factor of 6. The encapsulation process appears to constrain the dye and reduce deformation of the chromophore from planarity. This study shows how mechanical encapsulation as a rotaxane can be used as a rational design parameter to fine-tune the chemical and photochemical properties of squaraine dyes.

Squaraine Rotaxanes with Boat Conformation Macrocycles

PubMed Central

Fu, Na; Baumes, Jeffrey M.; Arunkumar, Easwaran; Noll, Bruce C.; Smith, Bradley D.

2010-01-01

Mechanical encapsulation of fluorescent, deep-red bis(anilino)squaraine dyes inside Leigh-type tetralactam macrocycles produces interlocked squaraine rotaxanes. The surrounding macrocycles are flexible and undergo rapid exchange of chair and boat conformations in solution. A series of X-ray crystal structures show how the rotaxane co-conformational exchange process involves simultaneous lateral oscillation of the macrocycle about the center of the encapsulated squaraine thread. Rotaxane macrocycles with 1,4-phenylene-sidewalls and 2,6-pyridine dicarboxamide bridging units are more likely to adopt boat conformations in the solid-state than analogous squaraine rotaxane systems with isophthalamide-containing macrocycles. A truncated squaraine dye, with a secondary amine attached directly to the central C4O2 core, is less electrophilic than the extended bis(anilino)squaraine analogue, but it is still susceptible to chemical and photochemical bleaching. Its stability is greatly enhanced when it is encapsulated as an interlocked squaraine rotaxane. An X-ray crystal structure of this truncated squaraine rotaxane shows the macrocycle in a boat conformation, and NMR studies indicate that the boat is maintained in solution. Encapsulation as a rotaxane increases the dye’s brightness by a factor of six. The encapsulation process appears to constrain the dye and reduce deformation of the chromophore from planarity. This study shows how mechanical encapsulation as a rotaxane can be used as a rational design parameter to fine-tune the chemical and photochemical properties of squaraine dyes. PMID:19639940

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

The results of a study for Task 3 of the Low Cost Solar Array Project, directed toward the development of a cost effective encapsulation system for photovoltaic modules using silicon based materials, are reported. Results of the following are discussed: (1) weather-ometer stressing vs. weathering history of silicon and silicon modified materials; (2) humidity/temperature cycling exposure; (3) exposure at high humidity/high temperature; (4) outdoor exposure stress; (5) thermal cycling stress; and (6) UV screening agents. The plans for the next quarter are outlined.

Rapid directed evolution of stabilized proteins with cellular high-throughput encapsulation solubilization and screening (CHESS).

PubMed

Yong, K J; Scott, D J

2015-03-01

Directed evolution is a powerful method for engineering proteins towards user-defined goals and has been used to generate novel proteins for industrial processes, biological research and drug discovery. Typical directed evolution techniques include cellular display, phage display, ribosome display and water-in-oil compartmentalization, all of which physically link individual members of diverse gene libraries to their translated proteins. This allows the screening or selection for a desired protein function and subsequent isolation of the encoding gene from diverse populations. For biotechnological and industrial applications there is a need to engineer proteins that are functional under conditions that are not compatible with these techniques, such as high temperatures and harsh detergents. Cellular High-throughput Encapsulation Solubilization and Screening (CHESS), is a directed evolution method originally developed to engineer detergent-stable G proteins-coupled receptors (GPCRs) for structural biology. With CHESS, library-transformed bacterial cells are encapsulated in detergent-resistant polymers to form capsules, which serve to contain mutant genes and their encoded proteins upon detergent mediated solubilization of cell membranes. Populations of capsules can be screened like single cells to enable rapid isolation of genes encoding detergent-stable protein mutants. To demonstrate the general applicability of CHESS to other proteins, we have characterized the stability and permeability of CHESS microcapsules and employed CHESS to generate thermostable, sodium dodecyl sulfate (SDS) resistant green fluorescent protein (GFP) mutants, the first soluble proteins to be engineered using CHESS. © 2014 Wiley Periodicals, Inc.

Enzyme catalysis: Evolution made easy

NASA Astrophysics Data System (ADS)

Wee, Eugene J. H.; Trau, Matt

2014-09-01

Directed evolution is a powerful tool for the development of improved enzyme catalysts. Now, a method that enables an enzyme, its encoding DNA and a fluorescent reaction product to be encapsulated in a gel bead enables the application of directed evolution in an ultra-high-throughput format.

Photopolymerizable liquid encapsulants for microelectronic devices

NASA Astrophysics Data System (ADS)

Baikerikar, Kiran K.

2000-10-01

Plastic encapsulated microelectronic devices consist of a silicon chip that is physically attached to a leadframe, electrically interconnected to input-output leads, and molded in a plastic that is in direct contact with the chip, leadframe, and interconnects. The plastic is often referred to as the molding compound, and is used to protect the chip from adverse mechanical, thermal, chemical, and electrical environments. Encapsulation of microelectronic devices is typically accomplished using a transfer molding process in which the molding compound is cured by heat. Most transfer molding processes suffer from significant problems arising from the high operating temperatures and pressures required to fill the mold. These aspects of the current process can lead to thermal stresses, incomplete mold filling, and wire sweep. In this research, a new strategy for encapsulating microelectronic devices using photopolymerizable liquid encapsulants (PLEs) has been investigated. The PLEs consist of an epoxy novolac-based vinyl ester resin (˜25 wt.%), fused silica filler (70--74 wt.%), and a photoinitiator, thermal initiator, and silane coupling agent. For these encapsulants, the use of light, rather than heat, to initiate the polymerization allows precise control over when the reaction starts, and therefore completely decouples the mold filling and the cure. The low viscosity of the PLEs allows for low operating pressures and minimizes problems associated with wire sweep. In addition, the in-mold cure time for the PLEs is equivalent to the in-mold cure times of current transfer molding compounds. In this thesis, the thermal and mechanical properties, as well as the viscosity and adhesion of photopolymerizable liquid encapsulants, are reported in order to demonstrate that a UV-curable formulation can have the material properties necessary for microelectronic encapsulation. In addition, the effects of the illumination time, postcure time, fused silica loading, and the inclusion of a thermal initiator on the thermal and mechanical properties of the final cured encapsulants have been investigated. The results show that the material properties of the PLEs are the same, if not better, than those exhibited by conventional transfer molding compounds and demonstrate the potential of using PLEs for encapsulating microelectronic devices.

Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

NASA Technical Reports Server (NTRS)

Chervenak, James; Wollack, Edward

2012-01-01

A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10 50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated. A degenerately doped silicon wafer has been chosen to provide a metallic ground plane. A metallic seed layer is patterned to enable attachment to the ground plane. Thick silicon dioxide films are deposited at low temperatures to provide tunable dielectric isolation without degrading the metallic seed layer. Superconducting wiring is deposited and patterned using microstripline filtering techniques to cut out the relevant frequencies. A low Tc superconductor is used so that it will attenuate power strongly above the gap frequency. Thick dielectric is deposited on top of the circuit, and then vias are patterned through both dielectric layers. A thick conductive film is deposited conformally over the entire circuit, except for the contact pads for the signal and bias attachments to complete the encapsulating ground plane. Filters are high-aspect- ratio rectangles, allowing close packing in one direction, while enabling the chip to feed through the wall of a copper enclosure. The chip is secured in the copper wall using a soft metal seal to make good thermal and electrical contact to the outer shield.

Encapsulation of ZnO particles by metal fluorides: Towards an application as transparent insulating coatings for windows

NASA Astrophysics Data System (ADS)

Trenque, Isabelle; Mornet, Stéphane; Duguet, Etienne; Majimel, Jérôme; Brüll, Annelise; Teinz, Katharina; Kemnitz, Erhard; Gaudon, Manuel

2013-01-01

Because ZnO is a promising candidate for getting efficient films or varnishes with thermal insulating abilities for windows applications, the effect of the encapsulation of ZnO particles in shells of low refractive index material on the improvement of the visible light transmission was investigated. ZnO-MgF2 core-shell particles were synthesized by deposition of fluoride sols on ZnO particles through a vacuum slip casting process like. The transmission behaviours were first indirectly studied by diffuse reflexion measurements on powder beds. Then, particle films were elaborated by a screen printing process which ensured direct transmission measurements. The encapsulation of ZnO particles with a coating shell of 1.3 wt.% of MgF2 improves the visible light transmission of 32%.

Evaluation of Transient Pin-Stress Requirements for Spacecraft Launching in Lightning Environments. Pain Free Analysis to Alleviate Those Pin Stress Headaches

NASA Technical Reports Server (NTRS)

Edwards, Paul; Terseck, Alex; Trout, Dawn

2016-01-01

Spacecraft are generally protected from direct lightning attachment by encapsulation within the payload fairing of a launch vehicle and the ground structures that exist at the launch site. Regardless of where lightning strikes, potentially damaging indirect effects prevail from the coupling of electromagnetic fields into a loop created by outer shield of the payload umbilical. The energy coupled into individual spacecraft circuits is dependent on the umbilical current drive, the cable transfer impedance and the source/ load circuitry, and the reference potential used. Lightning induced transient susceptibility of the spacecraft avionics needs to be fully understood in order to define realistic re-test criteria in the event of a lightning occurrence during the launch campaign. Use of standards such as RTCA/DO-160 & SAE 5412 has some applicability but do not represent the indirect environment adequately. This paper evaluates the launch pad environments, the measurement data available, and computer simulations to provide pain-free analysis to alleviate the transient pin-stress headaches for spacecraft launching in Lightning environments.

Assessment of Immune Isolation of Allogeneic Mouse Pancreatic Progenitor Cells by a Macroencapsulation Device

PubMed Central

Faleo, Gaetano; Lee, Karim; Nguyen, Vinh; Tang, Qizhi

2016-01-01

Background Embryonic-stem-cell (ESC)-derived islets hold the promise of providing a renewable source of tissue for the treatment of insulin-dependent diabetes. Encapsulation may allow ESC-derived islets to be transplanted without immunosuppression, thus enabling wider application of this therapy. Methods In this study, we investigated the immunogenicity of mouse pancreatic progenitor cells and efficacy of a new macroencapsulation device in protecting these cells against alloimmune and autoimmune responses in mouse models. Results Mouse pancreatic progenitor cells activated the indirect but not the direct pathway of alloimmune response and were promptly rejected in immune competent hosts. The new macroencapsulation device abolished T cell activation induced by allogeneic splenocytes and protected allogeneic MIN6 β cells and pancreatic progenitors from rejection even in pre-sensitized recipients. In addition, the device was effective in protecting MIN6 cells in spontaneously diabetic non-obese diabetic recipients against both alloimmune and recurring autoimmune responses. Conclusion Our results demonstrate that macroencapsulation can effectively prevent immune sensing and rejection of allogeneic pancreatic progenitor cells in fully sensitized and autoimmune hosts. PMID:26982952

Three-dimensional hybrid grid generation using advancing front techniques

NASA Technical Reports Server (NTRS)

Steinbrenner, John P.; Noack, Ralph W.

1995-01-01

A new 3-dimensional hybrid grid generation technique has been developed, based on ideas of advancing fronts for both structured and unstructured grids. In this approach, structured grids are first generate independently around individual components of the geometry. Fronts are initialized on these structure grids, and advanced outward so that new cells are extracted directly from the structured grids. Employing typical advancing front techniques, cells are rejected if they intersect the existing front or fail other criteria When no more viable structured cells exist further cells are advanced in an unstructured manner to close off the overall domain, resulting in a grid of 'hybrid' form. There are two primary advantages to the hybrid formulation. First, generating blocks with limited regard to topology eliminates the bottleneck encountered when a multiple block system is used to fully encapsulate a domain. Individual blocks may be generated free of external constraints, which will significantly reduce the generation time. Secondly, grid points near the body (presumably with high aspect ratio) will still maintain a structured (non-triangular or tetrahedral) character, thereby maximizing grid quality and solution accuracy near the surface.

Degradation of partially immersed glass: A new perspective

NASA Astrophysics Data System (ADS)

Chinnam, R. K.; Fossati, P. C. M.; Lee, W. E.

2018-05-01

The International Simple Glass (ISG) is a six-component borosilicate glass which was developed as a reference for international collaborative studies on high level nuclear waste encapsulation. Its corrosion behaviour is typically examined when it is immersed in a leaching solution, or when it is exposed to water vapour. In this study, an alternative situation is considered in which the glass is only partially immersed for 7 weeks at a temperature of 90 °C. In this case, half of the glass sample is directly in the solution itself, and the other half is in contact with a water film formed by condensation of water vapour that evaporated from the solution. This results in a different degradation behaviour compared to standard tests in which the material is fully immersed. In particular, whilst in standard tests the system reaches a steady state with a very low alteration rate thanks to the formation of a protective gel layer, in partially-immersed tests this steady state could not be reached because of the continuous alteration from the condensate water film. The constant input of ions from the emerged part of the sample caused a supersaturation of the solution, which resulted in early precipitation of secondary crystalline phases. This setup mimics storage conditions once small amounts of water have entered a glass waste form containing canister. It offers a more realistic outlook of corrosion mechanisms happening in such situations than standard fully-immersed corrosion tests.

Monodisperse Metal-Organic Framework Nanospheres with Encapsulated Core-Shell Nanoparticles Pt/Au@Pd@{Co2(oba)4(3-bpdh)2}4H2O for the Highly Selective Conversion of CO2 to CO.

PubMed

Zhao, Xi; Xu, Haitao; Wang, XiaoXiao; Zheng, Zhizhong; Xu, Zhenliang; Ge, Jianping

2018-05-02

A new microporous metal-organic framework (MOF) with formula {Co 2 (oba) 4 (3-bpdh) 2 }4H 2 O [oba = 4,4'-oxybis(benzoic acid); 3-bpdh = N, N'-bis-(1-pyridine-3-yl-ethylidene)-hydrazine] was assembled, and its morphology was found to undergo a microrod-to-nanosphere transformation with temperature variation. Core-shell Au@Pd functional nanoparticles (NPs) were successfully encapsulated in the center of the monodisperse nanospheres, and Pt NPs were well-dispersed and fully immobilized on the surface of Au@Pd@1Co to build the Pt/Au@Pd@1Co composites, which exhibited NPs catalytic activity for the reverse water gas shift reaction. The core-shell Au@Pd NPs in MOF significantly enchanced the CO selectivity of the catalyst, and the Pt NP loading on the surface of the nanosphere afforded a desirable CO 2 conversion.

Laser Encapsulation of Organic Electronics with Adapted Diode Lasers in Flexible Production Processes

NASA Astrophysics Data System (ADS)

Brosda, Maximilian; Olowinsky, Alexander; Pelzer, Alexander

Flexible organic electronics such as OLPV and OLED modules are highly sensitive against water and oxygen. To protect them against the environment and to ensure a long lifetime visual transparent ultra high barrier films are used for the encapsulation process. These multilayer films usually consist of a polymer substrate on which, depending on the requirements, various functional layers are applied. The organic device is then fully packed in this films. Instead of conventional joining these film with adhesive, a flexible laser based process can be an interesting alternative especially for roll2roll applications. According to a precise spectral analysis and a consideration of the interaction between the laser radiation and the individual layers of the film a suitable laser beam source is selected. With this laser beam source the weldability of the films is investigated. For analysis of the weldseam and the melted volume cross sections and scanning-electron-microscopy-images are prepared. The strength of the weld is determined by T-Peel tensile tests.

Mars Technology Rover with Arm-Mounted Percussive Coring Tool, Microimager, and Sample-Handling Encapsulation Containerization Subsystem

NASA Technical Reports Server (NTRS)

Younse, Paulo J.; Dicicco, Matthew A.; Morgan, Albert R.

2012-01-01

A report describes the PLuto (programmable logic) Mars Technology Rover, a mid-sized FIDO (field integrated design and operations) class rover with six fully drivable and steerable cleated wheels, a rocker-bogey suspension, a pan-tilt mast with panorama and navigation stereo camera pairs, forward and rear stereo hazcam pairs, internal avionics with motor drivers and CPU, and a 5-degrees-of-freedom robotic arm. The technology rover was integrated with an arm-mounted percussive coring tool, microimager, and sample handling encapsulation containerization subsystem (SHEC). The turret of the arm contains a percussive coring drill and microimager. The SHEC sample caching system mounted to the rover body contains coring bits, sample tubes, and sample plugs. The coring activities performed in the field provide valuable data on drilling conditions for NASA tasks developing and studying coring technology. Caching of samples using the SHEC system provide insight to NASA tasks investigating techniques to store core samples in the future.

Fabrication of Magnetic Barcoded Microcarriers for Biomolecular Labeling: SU-8 Encapsulated Magnetic Tags

NASA Astrophysics Data System (ADS)

Palfreyman, Justin J.; Beldon, Patrick; Hong, Bingyan; Vyas, Kunal N.; Cooper, Joshaniel F. K.; Mitrelias, Thanos; Barnes, Crispin H. W.

2010-12-01

Rows of rectangular magnetic elements with different aspect ratio are encapsulated in polymer microcarriers to form a novel magnetic label, or tag, for multiplexed biological and chemical assays. We demonstrate that each tag can be encoded using an external magnetic field applied to the whole tag, which will allow for in-flow writing, thanks to shape-anisotropy controlled coercivity of the individual bits. This paper focuses on the fabrication of our 2nd generation tags, which facilitate optical trapping, do not require a sacrificial release layer, and the alignment procedure has been simplified to a single step. A new procedure is described for recovering a functional surface from fully cross-linked SU-8 via a cerium (IV) ammonium nitrate based chemical etch, and a novel method for releasing patterned photoresist from a bare Si wafer is discussed. In addition, a series of homobifunctional amine spacer compounds are compared as a method of increasing the binding efficiency of surface probe molecules.

Towards a fully synthetic substitute of alginate: optimization of a thermal gelation/chemical cross-linking scheme ("tandem" gelation) for the production of beads and liquid-core capsules.

PubMed

Cellesi, F; Weber, W; Fussenegger, M; Hubbell, J A; Tirelli, N

2004-12-20

Fully synthetic polymers were used for the preparation of hydrogel beads and capsules, in a processing scheme that, originally designed for calcium alginate, was adapted to a "tandem" process, that is the combination a physical gelation with a chemical cross-linking. The polymers feature a Tetronic backbone (tetra armed Pluronics), which exhibits a reverse thermal gelation in water solutions within a physiological range of temperatures and pHs. The polymers bear terminal reactive groups that allow for a mild, but effective chemical cross-linking. Given an appropriate temperature jump, the thermal gelation provides a hardening kinetics similar to that of alginate. With slower kinetics, the chemical cross-linking then develops an irreversible and elastic gel structure, and determines its transport properties. In the present article this process has been optimized for the production of monodisperse, high elastic, hydrogel microbeads, and liquid-core microcapsules. We also show the feasibility of the use of liquid-core microcapsules in cell encapsulation. In preliminary experiments, CHO cells have been successfully encapsulated preserving their viability during the process and after incubation. The advantages of this process are mainly in the use of synthetic polymers, which provide great flexibility in the molecular design. This, in principle, allows for a precise tailoring of mechanical and transport properties and of bioactivity of the hydrogels, and also for a precise control in material purification.

Proton Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pluth, Michael; Bergman, Robert; Raymond, Kenneth

2009-04-10

Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expandingmore » to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK{sub a} units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization of protonated guests was translated into chemical catalysis by taking advantage of the potential for accelerating reactions that take place via positively charged transition states, which could be potentially stabilized by encapsulation. Orthoformates, generally stable in neutral or basic solution, were found to be suitable substrates for catalytic hydrolysis by the assembly. Orthoformates small enough to undergo encapsulation were readily hydrolyzed by the assembly in basic solution, with rate acceleration factors up to 3900 compared with those of the corresponding uncatalyzed reactions. Furthering the analogy to enzymes that obey Michaelis-Menten kinetics, we observed competitive inhibition with the inhibitor NPr{sub 4}{sup +}, thereby confirming that the interior cavity of the assembly was the active site for catalysis. Mechanistic studies revealed that the assembly is required for catalysis and that the rate-limiting step of the reaction involves proton transfer from hydronium to the encapsulated substrate. Encapsulation in the assembly changes the orthoformate hydrolysis from an A-1 mechanism (in which decomposition of the protonated substrate is the rate-limiting step) to an A-S{sub E}2 mechanism (in which proton transfer is the rate-limiting step). The study of hydrolysis in the assembly was next extended to acetals, which were also catalytically hydrolyzed by the assembly in basic solution. Acetal hydrolysis changed from the A-1 mechanism in solution to an A-2 mechanism inside the assembly, where attack of water on the protonated substrate is rate limiting. This work provides rare examples of assembly-catalyzed reactions that proceed with substantial rate accelerations despite the absence of functional groups in the cavity and with mechanisms fully elucidated by quantitative kinetic studies.« less

Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

NASA Astrophysics Data System (ADS)

Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

2013-03-01

Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide- co-glycolide) (PLGA) microparticles (size 1-4 μm, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

The use of silicone based adhesives to encapsulate manganin gauges for high stress experiments

NASA Astrophysics Data System (ADS)

Be'Ery, Ilan; Rosenberg, Zvi

2007-06-01

The use of commercial manganin stress gauges has been limited to stresses in the range of 0-20 GPa due to the short-circuiting of their encapsulating materials (epoxy, Kapton) at higher pressures. Researchers at Lawrence Livermore overcome this difficulty by embedding their gauges in Teflon sheets and measured shock pressures as high as 40 GPa. The fact that Teflon can keep its resistivity at high pressures is attributed to the lack of benzene rings in its structure. On the other hand, Teflon is difficult to work with as an encapsulating material because of its poor adhesive properties. In order to overcome this difficulty we encapsulated our foils in between two tapes of Teflon which have a silicone adhesive glued to it. These are 50 μm thick commercial tapes (manufactured by 3M, type #60) which have a 50 μm thick silicone adhesive (PSA -- pressure sensitive adhesive) on them. This adhesive is easy to work with, has no benzene rings in its structure and has a lower carbon content, compared to other adhesives. Several experiments were conducted in order to directly measure the resistivity of these tapes at high pressures, as well as using them to encapsulate our manganin foils for high pressure studies.

Doxycycline-encapsulated nanotube-modified dentin adhesives.

PubMed

Feitosa, S A; Palasuk, J; Kamocki, K; Geraldeli, S; Gregory, R L; Platt, J A; Windsor, L J; Bottino, M C

2014-12-01

This article presents details of fabrication, biological activity (i.e., anti-matrix metalloproteinase [anti-MMP] inhibition), cytocompatibility, and bonding characteristics to dentin of a unique doxycycline (DOX)-encapsulated halloysite nanotube (HNT)-modified adhesive. We tested the hypothesis that the release of DOX from the DOX-encapsulated nanotube-modified adhesive can effectively inhibit MMP activity. We incorporated nanotubes, encapsulated or not with DOX, into the adhesive resin of a commercially available bonding system (Scotchbond Multi-Purpose [SBMP]). The following groups were tested: unmodified SBMP (control), SBMP with nanotubes (HNT), and DOX-encapsulated nanotube-modified adhesive (HNT+DOX). Changes in degree of conversion (DC) and microtensile bond strength were evaluated. Cytotoxicity was examined on human dental pulp stem cells (hDPSCs). To prove the successful encapsulation of DOX within the adhesives-but, more important, to support the hypothesis that the HNT+DOX adhesive would release DOX at subantimicrobial levels-we tested the antimicrobial activity of synthesized adhesives and the DOX-containing eluates against Streptococcus mutans through agar diffusion assays. Anti-MMP properties were assessed via β-casein cleavage assays. Increasing curing times (10, 20, 40 sec) led to increased DC values. There were no statistically significant differences (p > .05) in DC within each increasing curing time between the modified adhesives compared to SBMP. No statistically significant differences in microtensile bond strength were noted. None of the adhesives eluates were cytotoxic to the human dental pulp stem cells. A significant growth inhibition of S. mutans by direct contact illustrates successful encapsulation of DOX into the experimental adhesive. More important, DOX-containing eluates promoted inhibition of MMP-1 activity when compared to the control. Collectively, our findings provide a solid background for further testing of encapsulated MMP inhibitors into the synthesis of therapeutic adhesives that may enhance the longevity of hybrid layers and the overall clinical performance of adhesively bonded resin composite restorations. © International & American Associations for Dental Research.

Doxycycline-Encapsulated Nanotube-Modified Dentin Adhesives

PubMed Central

Feitosa, S.A.; Palasuk, J.; Kamocki, K.; Geraldeli, S.; Gregory, R.L.; Platt, J.A.; Windsor, L.J.; Bottino, M.C.

2014-01-01

This article presents details of fabrication, biological activity (i.e., anti–matrix metalloproteinase [anti-MMP] inhibition), cytocompatibility, and bonding characteristics to dentin of a unique doxycycline (DOX)–encapsulated halloysite nanotube (HNT)–modified adhesive. We tested the hypothesis that the release of DOX from the DOX-encapsulated nanotube-modified adhesive can effectively inhibit MMP activity. We incorporated nanotubes, encapsulated or not with DOX, into the adhesive resin of a commercially available bonding system (Scotchbond Multi-Purpose [SBMP]). The following groups were tested: unmodified SBMP (control), SBMP with nanotubes (HNT), and DOX-encapsulated nanotube-modified adhesive (HNT+DOX). Changes in degree of conversion (DC) and microtensile bond strength were evaluated. Cytotoxicity was examined on human dental pulp stem cells (hDPSCs). To prove the successful encapsulation of DOX within the adhesives—but, more important, to support the hypothesis that the HNT+DOX adhesive would release DOX at subantimicrobial levels—we tested the antimicrobial activity of synthesized adhesives and the DOX-containing eluates against Streptococcus mutans through agar diffusion assays. Anti-MMP properties were assessed via β-casein cleavage assays. Increasing curing times (10, 20, 40 sec) led to increased DC values. There were no statistically significant differences (p > .05) in DC within each increasing curing time between the modified adhesives compared to SBMP. No statistically significant differences in microtensile bond strength were noted. None of the adhesives eluates were cytotoxic to the human dental pulp stem cells. A significant growth inhibition of S. mutans by direct contact illustrates successful encapsulation of DOX into the experimental adhesive. More important, DOX-containing eluates promoted inhibition of MMP-1 activity when compared to the control. Collectively, our findings provide a solid background for further testing of encapsulated MMP inhibitors into the synthesis of therapeutic adhesives that may enhance the longevity of hybrid layers and the overall clinical performance of adhesively bonded resin composite restorations. PMID:25201918

Recent progress on the scalable fabrication of hybrid polymer/SiO2 nanophotonic cavity arrays with an encapsulated MoS2 film

NASA Astrophysics Data System (ADS)

Hammer, Sebastian; Mangold, Hans-Moritz; Nguyen, Ariana E.; Martinez-Ta, Dominic; Naghibi Alvillar, Sahar; Bartels, Ludwig; Krenner, Hubert J.

2018-02-01

We review1 the fully-scalable fabrication of a large array of hybrid molybdenum disulfide (MoS2) - silicon dioxide (SiO2) one-dimensional (1D), freestanding photonic-crystal cavities (PCCs) capable of enhancement of the MoS2 photoluminescence (PL) at the narrow cavity resonance. As demonstrated in our prior work [S. Hammer et al., Sci. Rep. 7, 7251 (2017)]1, geometric mode tuning over the wide spectral range of MoS2 PL can be achieved by changing the PC period. In this contribution, we provide a step-by-step description of the fabrication process and give additional detailed information on the degradation of MoS2 by XeF2 vapor. We avoid potential damage of the MoS2 monolayer during the crucial XeF2 etch by refraining from stripping the electron beam (e-beam) resist after dry etching of the photonic crystal pattern. The remaining resist on top of the samples encapsulates and protects the MoS2 film during the entire fabrication process. Albeit the thickness of the remaining resists strongly depends on the fabrication process, the resulting encapsulation of the MoS2 layer improves the confinement to the optical modes and gives rise to a potential enhancement of the light-matter interaction.

Simultaneous quantification of tumor uptake for targeted and non-targeted liposomes and their encapsulated contents by ICP-MS

PubMed Central

Cheng, Zhiliang; Zaki, Ajlan Al; Hui, James Z; Tsourkas, Andrew

2012-01-01

Liposomes are intensively being developed for biomedical applications including drug and gene delivery. However, targeted liposomal delivery in cancer treatment is a very complicated multi-step process. Unfavorable liposome biodistribution upon intravenous administration and membrane destabilization in blood circulation could result in only a very small fraction of cargo reaching the tumors. It would therefore be desirable to develop new quantitative strategies to track liposomal delivery systems to improve the therapeutic index and decrease systemic toxicity. Here, we developed a simple and non-radiative method to quantify the tumor uptake of targeted and non-targeted control liposomes as well as their encapsulated contents simultaneously. Specifically, four different chelated lanthanide metals were encapsulated or surface-conjugated onto tumor-targeted and non-targeted liposomes, respectively. The two liposome formulations were then injected into tumor-bearing mice simultaneously and their tumor delivery was determined quantitatively via inductively coupled plasma-mass spectroscopy (ICP-MS), allowing for direct comparisons. Tumor uptake of the liposomes themselves and their encapsulated contents were consistent with targeted and non-targeted liposome formulations that were injected individually. PMID:22882145

Silk ionomers for encapsulation and differentiation of human MSCs

PubMed Central

Calabrese, Rossella; Kaplan, David L.

2012-01-01

The response of human bone marrow derived human mesenchymal stem cells (hMSCs) encapsulated in silk ionomer hydrogels was studied. Silk aqueous solutions with silk-poly-L-lysine or silk-poly-L-glutamate were formed into hydrogels via ultrasonication in situ with different net charges. hMSCs were encapsulated within the hydrogels and the impact of matrix charge was assessed over weeks in osteogenic, adipogenic and maintenance growth media. These modified silk charged polymers supported cell viability and proliferative potential, and the hMSCs were able to differentiate toward osteogenic or adipogenic lineages in the corresponding differentiation media. The silk/silk-poly-L-lysine hydrogels exhibited a positive effect on selective osteogenesis of hMSCs, inducing differentiation toward an osteogenic lineage even in the absence of osteogenic supplements, while also inhibiting adipogenesis. In contrast, silk/silk fibroin-poly-L-glutamate hydrogels supported both osteogenic and adipogenic differentiation of hMSCs when cultured under induction conditions. The results demonstrate the potential utility of silk-based ionomers in gel formats for hMSCs encapsulation and for directing hMSCs long term functional differentiation toward specific lineages. PMID:22824008

Proteinaceous Resin and Hydrophilic Encapsulation: A Self-Healing-Related Study

NASA Astrophysics Data System (ADS)

Zheng, Ting

Inspired by living organisms, self-healing materials have been designed as smart materials. Their automatic healing nature is achieved through the use of capsule in which the healing agent is encapsulated. The occurrence of cracks leads to ripping of the capsule, along with crack propagation and release of the healing agent that wets the crack surface to eventually heal (bond) the crack. Such automatic repair of the crack significantly extends the service life of the material. A vast majority of existing self-healing systems have been designed for the epoxy matrix - the most common commercially used thermoset - that possesses low crack resistance. Currently, self-healing systems have not yet been introduced for fully protein-based materials, despite their great potential to replace currently used synthesis precursors for the latter and the eco-friendly nature of self-healing materials. This has been probably due to two major obstacles: poor mechanical properties of the protein-based matrix, and extreme difficulty associated with the encapsulation of hydrophilic healing agents suitable for the protein-based matrix. This study provides possible solutions towards addressing both these obstacles. To improve the inherent mechanical properties of protein-based resin, soy protein isolate (SPI) was chosen as the model in this study. Dialdehyde carboxymethyl cellulose (DCMC) was synthesized and used as the crosslinking agent to modify the SPI film. As-synthesized DCMC - a fully bio-based material - exhibited high mechanical strength, excellent thermal stability, and reduced moisture sensitivity. Good compatibility and effective crosslinking were believed to be the key reasons for such property enhancements. However, these were accompanied by poor crack resistance, where self-healing is a pertinent solution. A novel healing system for the protein matrix was designed in this work via the use of formaldehyde as a healing agent. Subsequently, the well-acknowledged challenge, e.g. hydrophilic agent encapsulation, was addressed through the development of novel polyurethane-Poly(melamine-formaldehyde) (PU-PMF) dual-component capsules. Remarkably, the external PU insulation layer was fabricated through interfacial polymerization based on a water-in-oil-in-oil (W/O/O) emulsion template. Surface tension was identified as the main driving factor for the formation of the external oil phase. The internal PMF layer was observed to strongly influence the internal morphology of the capsule. A protocol was developed, and a typical capsule with dense and neat shell morphology with a shell/capsule diameter (around 3 %) was fabricated. This study provides solutions for the two aforementioned obstacles related to the development of the healing system for the protein-based materials.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1999-07-20

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1998-03-24

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Composition and process for the encapsulation and stabilization of radioactive hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1997-01-01

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Biomimetic Antigenic Nanoparticles Elicit Controlled Protective Immune Response to Influenza

PubMed Central

Patterson, Dustin P.; Rynda-Apple, Agnieszka; Harmsen, Ann L.; Harmsen, Allen G.; Douglas, Trevor

2013-01-01

Here we present a biomimetic strategy towards nanoparticle design for controlled immune response through encapsulation of conserved internal influenza proteins on the interior of virus like particles (VLPs) to direct CD8+ cytotoxic T cell protection. Programmed encapsulation and sequestration of the conserved nucleoprotein (NP) from influenza on the interior of a VLP, derived from the bacteriophage P22, results in a vaccine that provides multi-strain protection against 100 times lethal doses of influenza in an NP specific CD8+ T cell-dependent manner. VLP assembly and encapsulation of the immunogenic NP cargo protein is the result of a genetically programmed self-assembly making this strategy amendable to the quick production of vaccines to rapidly emerging pathogens. Addition of adjuvants or targeting molecules were not required for eliciting the protective response. PMID:23540530

Lifetime Improvement of Organic Light Emitting Diodes using LiF Thin Film and UV Glue Encapsulation

NASA Astrophysics Data System (ADS)

Huang, Jian-Ji; Su, Yan-Kuin; Chang, Ming-Hua; Hsieh, Tsung-Eong; Huang, Bohr-Ran; Wang, Shun-Hsi; Chen, Wen-Ray; Tsai, Yu-Sheng; Hsieh, Huai-En; Liu, Mark O.; Juang, Fuh-Shyang

2008-07-01

This work demonstrates the use of lithium fluoride (LiF) as a passivation layer and a newly developed UV glue for encapsulation on the LiF passivation layer to enhance the stability of organic light-emitting devices (OLEDs). Devices with double protective layers showed a 25-fold increase in operational lifetime compared to those without any packaging layers. LiF has a low melting point and insulating characteristics and it can be adapted as both a protective layer and pre-encapsulation film. The newly developed UV glue has a fast curing time of only 6 s and can be directly spin-coated onto the surface of the LiF passivation layer. The LiF thin film plus spin-coated UV glue is a simple packaging method that reduces the fabrication costs of OLEDs.

Schottky Noise and Beam Transfer Functions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaskiewicz, M.

2016-12-01

Beam transfer functions (BTF)s encapsulate the stability properties of charged particle beams. In general one excites the beam with a sinusoidal signal and measures the amplitude and phase of the beam response. Most systems are very nearly linear and one can use various Fourier techniques to reduce the number of measurements and/or simulations needed to fully characterize the response. Schottky noise is associated with the finite number of particles in the beam. This signal is always present. Since the Schottky current drives wakefields, the measured Schottky signal is influenced by parasitic impedances.

Ballistic Transport Exceeding 28 μm in CVD Grown Graphene.

PubMed

Banszerus, Luca; Schmitz, Michael; Engels, Stephan; Goldsche, Matthias; Watanabe, Kenji; Taniguchi, Takashi; Beschoten, Bernd; Stampfer, Christoph

2016-02-10

We report on ballistic transport over more than 28 μm in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit carrier mobilities of up to three million cm(2)/(Vs). The ballistic nature of charge transport is probed by measuring the bend resistance in cross- and square-shaped devices. Temperature-dependent measurements furthermore prove that ballistic transport is maintained exceeding 1 μm up to 200 K.

[7,13-Bis(2-aminobenzyl)-1,4,10-trioxa-7,13-diazacyclopentadecane]diisothiocyanatobarium(II).

PubMed

Avecilla, Fernando; Esteban, David; Platas-Iglesias, Carlos; De Blas, Andres; Rodríguez-Blas, Teresa

2003-01-01

The X-ray crystal structure of the title complex, [Ba(NCS)(2)(C(24)H(36)N(4)O(3))], indicates that the Ba(II) cation is nine-coordinate in the solid state, being fully encapsulated by the organic receptor ligand. The receptor adopts a syn arrangement, with both pendant arms oriented on the same side of the crown moiety. The distance between the two amine N atoms is 3.911 (12) A, while the pivotal N atoms are 5.322 (10) A apart.

Sprayed shielding of plastic-encapsulated electronic modules

NASA Technical Reports Server (NTRS)

Muller, A. N.

1969-01-01

Metallic coating directly sprayed on electronic modules provides simple and reliable lightweight protection against radio frequency interference. A plasma arc may be used. Aluminum and copper are the most effective metals.

Preparation of mesoporous silica microparticles by sol-gel/emulsion route for protein release.

PubMed

Vlasenkova, Mariya I; Dolinina, Ekaterina S; Parfenyuk, Elena V

2018-04-06

Encapsulation of therapeutic proteins into particles from appropriate material can improve both stability and delivery of the drugs, and the obtained particles can serve as a platform for development of their new oral formulations. The main goal of this work was development of sol-gel/emulsion method for preparation of silica microcapsules capable of controlled release of encapsulated protein without loss of its native structure. For this purpose, the reported in literature direct sol-gel/W/O/W emulsion method of protein encapsulation was used with some modifications, because the original method did not allow to prepare silica microcapsules capable for protein release. The particles were synthesized using sodium silicate and tetraethoxysilane as silica precursors and different compositions of oil phase. In vitro kinetics of bovine serum albumin (BSA) release in buffer (pH 7.4) was studied by Fourier transform infrared (FTIR) and fluorescence spectrometry, respectively. Structural state of encapsulated BSA and after release was evaluated. It was found that the synthesis conditions influenced substantially the porous structure of the unloaded silica particles, release properties of the BSA-loaded silica particles and structural state of the encapsulated and released protein. The modified synthesis conditions made it possible to obtain the silica particles capable of controlled release of the protein during a week without loss of the protein native structure.

Fisetin yeast-based bio-capsules via osmoporation: effects of process variables on the encapsulation efficiency and internalized fisetin content.

PubMed

de Câmara, Antonio Anchieta; Dupont, Sébastien; Beney, Laurent; Gervais, Patrick; Rosenthal, Amauri; Correia, Roberta Targino Pinto; Pedrini, Márcia Regina da Silva

2016-06-01

Osmoporation is an innovative method that can be used with food-grade yeast cells of Saccharomyces cerevisiae as natural encapsulating matrices. This technique overcomes barriers that difficult encapsulation and enables the internalization of fragile bioactive molecules such as fisetin into yeasts. In the present study, we assessed the effects of concentration, osmotic pressure, and temperature on the encapsulation efficiency (EE) and internalized fisetin content (IF). Two different quantification strategies were investigated: direct extraction (DE) without cell washing or freeze-drying steps and indirect extraction (IE) performed after washings with ethanol and freeze-drying. Our results showed that osmoporation improved EE (33 %) and IF (1.199 mg). The best experimental conditions were found by using DE. High-resolution images showed that the yeast cell envelope was preserved during osmoporation at 30 MPa and 84 % of yeast cells remained viable after treatment. Washing cells with organic solvent led to decreased EE (0.65 %) and IF (0.023 mg). This was probably due to either damages caused to yeast cell envelope or fisetin dragged out of cell. Overall, the results demonstrated the adequacy and relevant biotechnological potential of yeasts as encapsulating matrices for hydrophobic compounds. This fresh biotechnological approach has proven to be a promising tool for the production of bioactive-rich food products.

Capacitance-voltage analysis of electrical properties for WSe2 field effect transistors with high-k encapsulation layer

NASA Astrophysics Data System (ADS)

Ko, Seung-Pil; Shin, Jong Mok; Jang, Ho Kyun; You, Min Youl; Jin, Jun-Eon; Choi, Miri; Cho, Jiung; Kim, Gyu-Tae

2018-02-01

Doping effects in devices based on two-dimensional (2D) materials have been widely studied. However, detailed analysis and the mechanism of the doping effect caused by encapsulation layers has not been sufficiently explored. In this work, we present experimental studies on the n-doping effect in WSe2 field effect transistors (FETs) with a high-k encapsulation layer (Al2O3) grown by atomic layer deposition. In addition, we demonstrate the mechanism and origin of the doping effect. After encapsulation of the Al2O3 layer, the threshold voltage of the WSe2 FET negatively shifted with the increase of the on-current. The capacitance-voltage measurements of the metal insulator semiconductor (MIS) structure proved the presence of the positive fixed charges within the Al2O3 layer. The flat-band voltage of the MIS structure of Au/Al2O3/SiO2/Si was shifted toward the negative direction on account of the positive fixed charges in the Al2O3 layer. Our results clearly revealed that the fixed charges in the Al2O3 encapsulation layer modulated the Fermi energy level via the field effect. Moreover, these results possibly provide fundamental ideas and guidelines to design 2D materials FETs with high-performance and reliability.

Degradation of thermally-cured silicone encapsulant under terrestrial UV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Can; Miller, David C.; Tappan, Ian A.

Concentrator photovoltaic (CPV) modules operate in extreme conditions, including enhanced solar flux, elevated operating temperature, and frequent thermal cycling. Coupled with active environmental species such as oxygen and moisture, the operating conditions pose a unique materials challenge for guaranteeing operational lifetimes of greater than 25 years. Specifically, the encapsulants used in the optical elements are susceptible to environmental degradation during operation. For example, the interfaces must remain in contact to prevent optical attenuation and thermal runaway. We developed fracture mechanics based metrologies to characterize the adhesion of the silicone encapsulant and its adjacent surfaces, as well as the cohesion ofmore » the encapsulant. Further, we studied the effects of weathering on adhesion using an outdoor concentrator operating in excess of 1100 times the AM1.5 direct irradiance and in indoor environmental chambers with broadband ultraviolet (UV) irradiation combined with controlled temperature and humidity. We observed a sharp initial increase in adhesion energy followed by a gradual decrease in adhesion as a result of both outdoor concentrator exposure and indoor UV weathering. We characterized changes in mechanical properties and chemical structures using XPS, FTIR, and DMA to understand the fundamental connection between mechanical strength and the degradation of the silicone encapsulant. We developed physics based models to explain the change in adhesion and to predict operational lifetimes of the materials and their interfaces.« less

Guiding principle for crystalline Si photovoltaic modules with high tolerance to acetic acid

NASA Astrophysics Data System (ADS)

Masuda, Atsushi; Hara, Yukiko

2018-04-01

A guiding principle for highly reliable crystalline Si photovoltaic modules, especially those with high tolerance to acetic acid generated by hydrolysis reaction between water vapor and an ethylene-vinyl acetate (EVA) encapsulant, is proposed. Degradation behavior evaluated by the damp heat test strongly depends on Ag finger electrodes and also EVA encapsulants. The acetic acid concentration in EVA on the glass side directly determines the degradation behavior. The most important factor for high tolerance is the type of Ag finger electrode materials when using an EVA encapsulant. Photovoltaic modules using newly developed crystalline Si cells with improved Ag finger electrode materials keep their maximum power of 80% of the initial value even after the damp heat test at 85 °C and 85% relative humidity for 10000 h. The pattern of dark regions in electroluminescence images is also discussed on the basis of the dynamics of acetic acid in the modules.

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

PubMed Central

Nardello-Rataj, Véronique

2014-01-01

Summary Host–guest chemistry is useful for the construction of nanosized objects. Some of the widely used hosts are probably the cyclodextrins (CDs). CDs can form water-soluble complexes with numerous hydrophobic compounds. They have been widespread used in medicine, drug delivery and are of interest for the biocides encapsulation. Indeed, this enables the development of more or less complex systems that release antimicrobial agents with time. In this paper, the general features of CDs and their applications in the field of biocides have been reviewed. As the key point is the formation of biocide–CD inclusion complexes, this review deals with this in depth and the advantages of biocide encapsulation are highlighted throughout several examples from the literature. Finally, some future directions of investigation have been proposed. We hope that scientists studying biocide applications receive inspiration from this review to exploit the opportunities offered by CDs in their respective research areas. PMID:25550722

Detection of Multiple Pathogens in Serum Using Silica-Encapsulated Nanotags in a Surface-Enhanced Raman Scattering-Based Immunoassay.

PubMed

Neng, Jing; Li, Yina; Driscoll, Ashley J; Wilson, William C; Johnson, Patrick A

2018-06-06

A robust immunoassay based on surface-enhanced Raman scattering (SERS) has been developed to simultaneously detect trace quantities of multiple pathogenic antigens from West Nile virus, Rift Valley fever virus, and Yersinia pestis in fetal bovine serum. Antigens were detected by capture with silica-encapsulated nanotags and magnetic nanoparticles conjugated with polyclonal antibodies. The magnetic pull-down resulted in aggregation of the immune complexes, and the silica-encapsulated nanotags provided distinct spectra corresponding to each antigen captured. The limit of detection was ∼10 pg/mL in 20% fetal bovine serum, a significant improvement over previous studies in terms of sensitivity, level of multiplexing, and medium complexity. This highly sensitive multiplex immunoassay platform provides a promising method to detect various antigens directly in crude serum samples without the tedious process of sample preparation, which is desirable for on-site diagnostic testing and real-time disease monitoring.

Development of a non-contextual model for determining the autonomy level of intelligent unmanned systems

NASA Astrophysics Data System (ADS)

Durst, Phillip J.; Gray, Wendell; Trentini, Michael

2013-05-01

A simple, quantitative measure for encapsulating the autonomous capabilities of unmanned systems (UMS) has yet to be established. Current models for measuring a UMS's autonomy level require extensive, operational level testing, and provide a means for assessing the autonomy level for a specific mission/task and operational environment. A more elegant technique for quantifying autonomy using component level testing of the robot platform alone, outside of mission and environment contexts, is desirable. Using a high level framework for UMS architectures, such a model for determining a level of autonomy has been developed. The model uses a combination of developmental and component level testing for each aspect of the UMS architecture to define a non-contextual autonomous potential (NCAP). The NCAP provides an autonomy level, ranging from fully non- autonomous to fully autonomous, in the form of a single numeric parameter describing the UMS's performance capabilities when operating at that level of autonomy.

Composition and process for the encapsulation and stabilization of radioactive hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1997-07-15

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a ``clean`` polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1998-03-24

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a ``clean`` polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Large Excitonic Reflectivity of Monolayer MoSe2 Encapsulated in Hexagonal Boron Nitride

NASA Astrophysics Data System (ADS)

Scuri, Giovanni; Zhou, You; High, Alexander A.; Wild, Dominik S.; Shu, Chi; De Greve, Kristiaan; Jauregui, Luis A.; Taniguchi, Takashi; Watanabe, Kenji; Kim, Philip; Lukin, Mikhail D.; Park, Hongkun

2018-01-01

We demonstrate that a single layer of MoSe2 encapsulated by hexagonal boron nitride can act as an electrically switchable mirror at cryogenic temperatures, reflecting up to 85% of incident light at the excitonic resonance. This high reflectance is a direct consequence of the excellent coherence properties of excitons in this atomically thin semiconductor. We show that the MoSe2 monolayer exhibits power-and wavelength-dependent nonlinearities that stem from exciton-based lattice heating in the case of continuous-wave excitation and exciton-exciton interactions when fast, pulsed laser excitation is used.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1999-07-20

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a clean'' polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Sol-Gel Matrices For Direct Colorimetric Detection Of Analytes

DOEpatents

Charych, Deborah H.; Sasaki, Darryl; Yamanaka, Stacey

2002-11-26

The present invention relates to methods and compositions for the direct detection of analytes using color changes that occur in immobilized biopolymeric material in response to selective binding of analytes to their surface. In particular, the present invention provides methods and compositions related to the encapsulation of biopolymeric material into metal oxide glass using the sol-gel method.

Sol-gel matrices for direct colorimetric detection of analytes

DOEpatents

Charych, Deborah H.; Sasaki, Darryl; Yamanaka, Stacey

2000-01-01

The present invention relates to methods and compositions for the direct detection of analytes using color changes that occur in immobilized biopolymeric material in response to selective binding of analytes to their surface. In particular, the present invention provides methods and compositions related to the encapsulation of biopolymeric material into metal oxide glass using the sol-gel method.

Engraftment of human induced pluripotent stem cell-derived hepatocytes in immunocompetent mice via 3D co-aggregation and encapsulation

PubMed Central

Song, Wei; Lu, Yen-Chun; Frankel, Angela S.; An, Duo; Schwartz, Robert E.; Ma, Minglin

2015-01-01

Cellular therapies for liver diseases and in vitro models for drug testing both require functional human hepatocytes (Hum-H), which have unfortunately been limited due to the paucity of donor liver tissues. Human pluripotent stem cells (hPSCs) represent a promising and potentially unlimited cell source to derive Hum-H. However, the hepatic functions of these hPSC-derived cells to date are not fully comparable to adult Hum-H and are more similar to fetal ones. In addition, it has been challenging to obtain functional hepatic engraftment of these cells with prior studies having been done in immunocompromised animals. In this report, we demonstrated successful engraftment of human induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (iPS-H) in immunocompetent mice by pre-engineering 3D cell co-aggregates with stromal cells (SCs) followed by encapsulation in recently developed biocompatible hydrogel capsules. Notably, upon transplantation, human albumin and α1-antitrypsin (A1AT) in mouse sera secreted by encapsulated iPS-H/SCs aggregates reached a level comparable to the primary Hum-H/SCs control. Further immunohistochemistry of human albumin in retrieved cell aggregates confirmed the survival and function of iPS-H. This proof-of-concept study provides a simple yet robust approach to improve the engraftment of iPS-H, and may be applicable to many stem cell-based therapies. PMID:26592180

[Prediction of Encapsulation Temperatures of Copolymer Films in Photovoltaic Cells Using Hyperspectral Imaging Techniques and Chemometrics].

PubMed

Lin, Ping; Chen, Yong-ming; Yao, Zhi-lei

2015-11-01

A novel method of combination of the chemometrics and the hyperspectral imaging techniques was presented to detect the temperatures of Ethylene-Vinyl Acetate copolymer (EVA) films in photovoltaic cells during the thermal encapsulation process. Four varieties of the EVA films which had been heated at the temperatures of 128, 132, 142 and 148 °C during the photovoltaic cells production process were used for investigation in this paper. These copolymer encapsulation films were firstly scanned by the hyperspectral imaging equipment (Spectral Imaging Ltd. Oulu, Finland). The scanning band range of hyperspectral equipemnt was set between 904.58 and 1700.01 nm. The hyperspectral dataset of copolymer films was randomly divided into two parts for the training and test purpose. Each type of the training set and test set contained 90 and 10 instances, respectively. The obtained hyperspectral images of EVA films were dealt with by using the ENVI (Exelis Visual Information Solutions, USA) software. The size of region of interest (ROI) of each obtained hyperspectral image of EVA film was set as 150 x 150 pixels. The average of reflectance hyper spectra of all the pixels in the ROI was used as the characteristic curve to represent the instance. There kinds of chemometrics methods including partial least squares regression (PLSR), multi-class support vector machine (SVM) and large margin nearest neighbor (LMNN) were used to correlate the characteristic hyper spectra with the encapsulation temperatures of of copolymer films. The plot of weighted regression coefficients illustrated that both bands of short- and long-wave near infrared hyperspectral data contributed to enhancing the prediction accuracy of the forecast model. Because the attained reflectance hyperspectral data of EVA materials displayed the strong nonlinearity, the prediction performance of linear modeling method of PLSR declined and the prediction precision only reached to 95%. The kernel-based forecast models were introduced to eliminate the impact of nonlinear hyperspectral data to some extent through mapping the original nonlinear hyperspectral data to the high dimensional linear feature space, so the relationship between the nonlinear hyperspectral data and the encapsulation temperatures of EVA films was fully disclosed finally. Compared with the prediction results of three proposed models, the prediction performance of LMNN was superior to the other two, whose final recognition accuracy achieved 100%. The results indicated that the methods of combination of LMNN model with the hyperspectral imaging techniques was the best one for accurately and rapidly determining the encapsulation temperatures of EVA films of photovoltaic cells. In addition, this paper had created the ideal conditions for automatically monitoring and effectively controlling the encapsulation temperatures of EVA films in the photovoltaic cells production process.

Biodegradable nanoparticles for improved kidney bioavailability of rhein: preparation, characterization, plasma, and kidney pharmacokinetics.

PubMed

Wei, Yinghui; Luo, Xiaoting; Guan, Jiani; Ma, Jianping; Zhong, Yicong; Luo, Jingwen; Li, Fanzhu

2017-11-01

The aim of this work is to develop biodegradable nanoparticles for improved kidney bioavailability of rhein (RH). RH-loaded nanoparticles were prepared using an emulsification solvent evaporation method and fully characterized by several techniques. Kidney pharmacokinetics was assessed by implanting a microdialysis probe in rat's kidney cortex. Blood samples were simultaneously collected (via femoral artery) for assessing plasma pharmacokinetics. Optimized nanoparticles were small, with a mean particle size of 132.6 ± 5.95 nm, and homogeneously dispersed. The charge on the particles was nearly zero, the encapsulation efficiency was 62.71 ± 3.02%, and the drug loading was 1.56 ± 0.15%. In vitro release of RH from the nanoparticles showed an initial burst release followed by a sustained release. Plasma and kidney pharmacokinetics showed that encapsulation of RH into nanoparticles significantly increased its kidney bioavailability (AUC kidney /AUC plasma  = 0.586 ± 0.072), clearly indicating that nanoparticles are a promising strategy for kidney drug delivery.

Magnetotransport in heterostructures of transition metal dichalcogenides and graphene

NASA Astrophysics Data System (ADS)

Völkl, Tobias; Rockinger, Tobias; Drienovsky, Martin; Watanabe, Kenji; Taniguchi, Takashi; Weiss, Dieter; Eroms, Jonathan

2017-09-01

We use a van der Waals pickup technique to fabricate different heterostructures containing WSe2(WS2) and graphene. The heterostructures were structured by plasma etching, contacted by one-dimensional edge contacts, and a top gate was deposited. For graphene /WSe2/SiO2 samples we observe mobilities of ˜12 000 cm2V-1s-1 . Magnetic-field-dependent resistance measurements on these samples show a peak in the conductivity at low magnetic fields. This dip is attributed to the weak antilocalization (WAL) effect, stemming from spin-orbit coupling. Samples where graphene is encapsulated between WSe2(WS2) and hexagonal boron nitride show a much higher mobility of up to ˜120 000 cm2V-1s-1 . However, in these samples no WAL peak can be observed. We attribute this to a transition from the diffusive to the quasiballistic regime. At low magnetic fields a resistance peak appears, which we ascribe to a size effect due to boundary scattering. Shubnikov-de Haas oscillations in fully encapsulated samples show all integer filling factors due to complete lifting of the spin and valley degeneracies.

Time-Resolved SAXS Studies of the Kinetics of Thermally Triggered Release of Encapsulated Silica Nanoparticles from Block Copolymer Vesicles

PubMed Central

2017-01-01

Silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles are prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). As the concentration of silica nanoparticles present during the PISA synthesis is increased up to 35% w/w, higher degrees of encapsulation of this component within the vesicles can be achieved. After centrifugal purification to remove excess non-encapsulated silica nanoparticles, SAXS, DCP, and TGA analysis indicates encapsulation of up to hundreds of silica nanoparticles per vesicle. In the present study, the thermally triggered release of these encapsulated silica nanoparticles is examined by cooling to 0 °C for 30 min, which causes in situ vesicle dissociation. Transmission electron microscopy studies confirm the change in diblock copolymer morphology and also enable direct visualization of the released silica nanoparticles. Time-resolved small-angle X-ray scattering is used to quantify the extent of silica release over time. For an initial silica concentration of 5% w/w, cooling induces a vesicle-to-sphere transition with subsequent nanoparticle release. For higher silica concentrations (20 or 30% w/w) cooling only leads to perforation of the vesicle membranes, but silica nanoparticles are nevertheless released through the pores. For vesicles prepared in the presence of 30% w/w silica, the purified silica-loaded vesicles were cooled to 0 °C for 30 min, and SAXS patterns were collected every 15 s. A new SAXS model has been developed to determine both the mean volume fraction of encapsulated silica within the vesicles and the scattering length density. Satisfactory data fits to the experimental SAXS patterns were obtained using this model. PMID:28626247

Effects of a novel encapsulating technique on the temperature tolerance and anti-colitis activity of the probiotic bacterium Lactobacillus kefiranofaciens M1.

PubMed

Wang, Sheng-Yao; Ho, Yi-Fang; Chen, Yen-Po; Chen, Ming-Ju

2015-04-01

Lactobacillus kefiranofaciens M1 (M1) has been shown to possess many different beneficial health effects including anti-colitis activity. The purpose of this study was to develop a novel and easily scaled-up encapsulating technique that would improve the temperature tolerance of the bacterium and reduce the sensitivity of the organism to gastrointestinal fluid. A mixture of sodium alginate, gellan gum and skim milk powder was used as a coating material to entrap M1. The M1 gel was then directly freeze dried in order to dehydrate the covering and form microcapsules. The viable cell numbers of M1 present only dropped ten folds after the freeze-drying encapsulation process. The viable cell counts remained constant at 5 × 10(7) CFU/g after heating from 25 °C to 75 °C and holding at 75 °C for 1 min. The viable cell counts were reduced to 10(6) CFU/g and 10(5) CFU/g after 8-week storage at 4 °C and subsequent heat treatment with simulated gastrointestinal fluid test (SGFT) and bile salts, respectively. The effect of encapsulated M1 on the organism's anti-colitis activity was evaluated using the dextran sodium sulfate (DSS) induced colitis mouse model. An in vivo study indicated that administration of heat treated encapsulated M1 was able to ameliorate DSS-induced colitis producing a significant reduction in the bleeding score and an attenuation of inflammatory score. These findings clearly demonstrate that encapsulation of M1 using this novel technique is able to provide good protection from temperature changes and SGFT treatment and also does not affect the organism's anti-colitis activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recent Advances in Bioprinting and Applications for Biosensing

PubMed Central

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

2014-01-01

Future biosensing applications will require high performance, including real-time monitoring of physiological events, incorporation of biosensors into feedback-based devices, detection of toxins, and advanced diagnostics. Such functionality will necessitate biosensors with increased sensitivity, specificity, and throughput, as well as the ability to simultaneously detect multiple analytes. While these demands have yet to be fully realized, recent advances in biofabrication may allow sensors to achieve the high spatial sensitivity required, and bring us closer to achieving devices with these capabilities. To this end, we review recent advances in biofabrication techniques that may enable cutting-edge biosensors. In particular, we focus on bioprinting techniques (e.g., microcontact printing, inkjet printing, and laser direct-write) that may prove pivotal to biosensor fabrication and scaling. Recent biosensors have employed these fabrication techniques with success, and further development may enable higher performance, including multiplexing multiple analytes or cell types within a single biosensor. We also review recent advances in 3D bioprinting, and explore their potential to create biosensors with live cells encapsulated in 3D microenvironments. Such advances in biofabrication will expand biosensor utility and availability, with impact realized in many interdisciplinary fields, as well as in the clinic. PMID:25587413

Ultrastructure of inclusion bodies in annulus cells in the degenerating human intervertebral disc.

PubMed

Gruber, H E; Hanley, E N

2009-06-01

The rough endoplasmic reticulum (rER) of the cell has an architectural editing function that checks whether protein structure and three-dimensional assembly have occurred properly prior to export of newly synthesized material out of the cell. If these have been faulty, the material is retained within the rER as an inclusion body. Inclusion bodies have been identified previously in chondrocytes and osteoblasts in chondrodysplasias and osteogenesis imperfecta. Inclusion bodies in intervertebral disc cells, however, have only recently been recognized. Our objectives were to use transmission electron microscopy to analyze more fully inclusion bodies in the annulus pulposus and to study the extracellular matrix (ECM) surrounding cells containing inclusion bodies. ECM frequently encapsulated cells with inclusion bodies, and commonly contained prominent banded aggregates of Type VI collagen. Inclusion body material had several morphologies, including relatively smooth, homogeneous material, or a rougher, less homogeneous feature. Such findings expand our knowledge of the fine structure of the human disc cell and ECM during disc degeneration, and indicate the potential utility of ultrastructural identification of discs with intracellular inclusion bodies as a screening method for molecular studies directed toward identification of defective gene products in degenerating discs.

Restoring visual perception using microsystem technologies: engineering and manufacturing perspectives.

PubMed

Krisch, I; Hosticka, B J

2007-01-01

Microsystem technologies offer significant advantages in the development of neural prostheses. In the last two decades, it has become feasible to develop intelligent prostheses that are fully implantable into the human body with respect to functionality, complexity, size, weight, and compactness. Design and development enforce collaboration of various disciplines including physicians, engineers, and scientists. The retina implant system can be taken as one sophisticated example of a prosthesis which bypasses neural defects and enables direct electrical stimulation of nerve cells. This micro implantable visual prosthesis assists blind patients to return to the normal course of life. The retina implant is intended for patients suffering from retinitis pigmentosa or macular degeneration. In this contribution, we focus on the epiretinal prosthesis and discuss topics like system design, data and power transfer, fabrication, packaging and testing. In detail, the system is based upon an implantable micro electro stimulator which is powered and controlled via a wireless inductive link. Microelectronic circuits for data encoding and stimulation are assembled on flexible substrates with an integrated electrode array. The implant system is encapsulated using parylene C and silicone rubber. Results extracted from experiments in vivo demonstrate the retinotopic activation of the visual cortex.

Zwitterionic Nanocages Overcome the Efficacy Loss of Biologic Drugs.

PubMed

Li, Bowen; Yuan, Zhefan; Zhang, Peng; Sinclair, Andrew; Jain, Priyesh; Wu, Kan; Tsao, Caroline; Xie, Jingyi; Hung, Hsiang-Chieh; Lin, Xiaojie; Bai, Tao; Jiang, Shaoyi

2018-04-01

For biotherapeutics that require multiple administrations to fully cure diseases, the induction of undesirable immune response is one common cause for the failure of their treatment. Covalent binding of hydrophilic polymers to proteins is commonly employed to mitigate potential immune responses. However, while this technique is proved to partially reduce the antibodies (Abs) reactive to proteins, it may induce Abs toward their associated polymers and thus result in the loss of efficacy. Zwitterionic poly(carboxybetaine) (PCB) is recently shown to improve the immunologic properties of proteins without inducing any antipolymer Abs against itself. However, it is unclear if the improved immunologic profiles can translate to better clinical outcomes since improved immunogenicity cannot directly reflect amelioration in efficacy. Here, a PCB nanocage (PCB NC) is developed, which can physically encase proteins while keeping their structure intact. PCB NC encapsulation of uricase, a highly immunogenic enzyme, is demonstrated to eradicate all the immune responses. To bridge the gap between immunogenicity and efficacy studies, the therapeutic performance of PCB NC uricase is evaluated and compared with its PEGylated counterpart in a clinical-mimicking gouty rat model to determine any loss of efficacy evoked after five administrations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photovoltaic device with increased light absorption and method for its manufacture

DOEpatents

Glatfelter, Troy; Vogeli, Craig; Call, Jon; Hammond, Ginger

1993-07-20

A photovoltaic cell having a light-directing optical element integrally formed in an encapsulant layer thereof. The optical element redirects light to increase the internal absorption of light incident on the photovoltaic device.

Modular microfluidic valve structures based on reversible thermoresponsive ionogel actuators.

PubMed

Benito-Lopez, Fernando; Antoñana-Díez, Marta; Curto, Vincenzo F; Diamond, Dermot; Castro-López, Vanessa

2014-09-21

This paper reports for the first time the use of a cross-linked poly(N-isopropylacrylamide) ionogel encapsulating the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulphate as a thermoresponsive and modular microfluidic valve. The ionogel presents superior actuation behaviour to its equivalent hydrogel. Ionogel swelling and shrinking mechanisms and kinetics are investigated as well as the performance of the ionogel when integrated as a valve in a microfluidic device. The modular microfluidic valve demonstrates fully a reversible on-off behaviour without failure for up to eight actuation cycles and a pressure resistance of 1100 mbar.

KSC-98pc1353

NASA Image and Video Library

1998-10-16

KENNEDY SPACE CENTER, FLA. -- In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the Mars Polar Lander spacecraft is on display for the media, showing an almost fully installed set of components for its launch planned for Jan. 3, 1999. The solar-powered spacecraft is designed to touch down on the Martian surface near the northern-most boundary of the south pole in order to study the water cycle there. The lander also will help scientists learn more about climate change and current resources on Mars, studying such things as frost, dust, water vapor and condensates in the Martian atmosphere

Repetitively Coupled Chemical Reduction and Galvanic Exchange as a Synthesis Strategy for Expanding Applicable Number of Pt Atoms in Dendrimer-Encapsulated Pt Nanoparticles.

PubMed

Cho, Taehoon; Yoon, Chang Won; Kim, Joohoon

2018-06-13

In this study, we report the controllable synthesis of dendrimer-encapsulated Pt nanoparticles (Pt DENs) utilizing repetitively coupled chemical reduction and galvanic exchange reactions. The synthesis strategy allows the expansion of the applicable number of Pt atoms encapsulated inside dendrimers to more than 1000 without being limited by the fixed number of complexation sites for Pt 2+ precursor ions in the dendrimers. The synthesis of Pt DENs is achieved in a short period of time (i.e., ∼10 min) simply by the coaddition of appropriate amounts of Cu 2+ and Pt 2+ precursors into aqueous dendrimer solution and subsequent addition of reducing agents such as BH 4 - , resulting in fast and selective complexation of Cu 2+ with the dendrimers and subsequent chemical reduction of the complexed Cu 2+ while uncomplexed Pt 2+ precursors remain oxidized. Interestingly, the chemical reduction of Cu 2+ , leading to the formation of Cu nanoparticles encapsulated inside the dendrimers, is coupled with the galvanic exchange of the Cu nanoparticles with the nearby Pt 2+ . This coupling repetitively proceeds until all of the added Pt 2+ ions form into Pt nanoparticles encapsulated inside the dendrimers. In contrast to the conventional method utilizing direct chemical reduction, this repetitively coupled chemical reduction and galvanic exchange enables a substantial increase in the applicable number of Pt atoms up to 1320 in Pt DENs while maintaining the unique features of DENs.

Attention and multisensory modulation argue against total encapsulation.

PubMed

de Haas, Benjamin; Schwarzkopf, Dietrich Samuel; Rees, Geraint

2016-01-01

Firestone & Scholl (F&S) postulate that vision proceeds without any direct interference from cognition. We argue that this view is extreme and not in line with the available evidence. Specifically, we discuss two well-established counterexamples: Attention directly affects core aspects of visual processing, and multisensory modulations of vision originate on multiple levels, some of which are unlikely to fall "within perception."

Service-oriented model-encapsulation strategy for sharing and integrating heterogeneous geo-analysis models in an open web environment

NASA Astrophysics Data System (ADS)

Yue, Songshan; Chen, Min; Wen, Yongning; Lu, Guonian

2016-04-01

Earth environment is extremely complicated and constantly changing; thus, it is widely accepted that the use of a single geo-analysis model cannot accurately represent all details when solving complex geo-problems. Over several years of research, numerous geo-analysis models have been developed. However, a collaborative barrier between model providers and model users still exists. The development of cloud computing has provided a new and promising approach for sharing and integrating geo-analysis models across an open web environment. To share and integrate these heterogeneous models, encapsulation studies should be conducted that are aimed at shielding original execution differences to create services which can be reused in the web environment. Although some model service standards (such as Web Processing Service (WPS) and Geo Processing Workflow (GPW)) have been designed and developed to help researchers construct model services, various problems regarding model encapsulation remain. (1) The descriptions of geo-analysis models are complicated and typically require rich-text descriptions and case-study illustrations, which are difficult to fully represent within a single web request (such as the GetCapabilities and DescribeProcess operations in the WPS standard). (2) Although Web Service technologies can be used to publish model services, model users who want to use a geo-analysis model and copy the model service into another computer still encounter problems (e.g., they cannot access the model deployment dependencies information). This study presents a strategy for encapsulating geo-analysis models to reduce problems encountered when sharing models between model providers and model users and supports the tasks with different web service standards (e.g., the WPS standard). A description method for heterogeneous geo-analysis models is studied. Based on the model description information, the methods for encapsulating the model-execution program to model services and for describing model-service deployment information are also included in the proposed strategy. Hence, the model-description interface, model-execution interface and model-deployment interface are studied to help model providers and model users more easily share, reuse and integrate geo-analysis models in an open web environment. Finally, a prototype system is established, and the WPS standard is employed as an example to verify the capability and practicability of the model-encapsulation strategy. The results show that it is more convenient for modellers to share and integrate heterogeneous geo-analysis models in cloud computing platforms.

Reclaiming hijacked phagosomes: Hybrid nano-in-micro encapsulated MIAP peptide ensures host directed therapy by specifically augmenting phagosome-maturation and apoptosis in TB infected macrophage cells.

PubMed

Sharma, Ankur; Vaghasiya, Kalpesh; Gupta, Pushpa; Gupta, Umesh Datta; Verma, Rahul Kumar

2018-01-30

TB-Superbugs have emerged as one of the most challenging global health threat due to the decrease in effectiveness of conventional antibiotics. Meanwhile, Host defense peptides (HDP) have evolved as an alternative to classical therapeutics with lesser susceptibility of resistance. We describe the potential of nano-encapsulated synthetic Magainin-I analog peptide (MIAP) as Host Directed Therapy against TB. Micron-sized inhalable platform "Porous Nanoparticle Aggregates Particles (PNAP)" with nano-scale physiognomies were developed to improve the delivery of MIAP-peptide to the lungs and enhance its stability. This particle engineering enabled more control over aerodynamic characteristics and bioactive release. Antimicrobial and mechanistic studies were carried out against virulent H37Rv TB bacteria. These MIAP-PNAP nano-assemblies demonstrated dose and time dependent antibacterial action against virulent M.tb for at least 96 h, with up to ∼3.03-log CFU reduction in numbers of viable bacteria compared to untreated group. These MIAP-PNAP at concentration of 50 μM and above showed significant antibacterial effects on M.tb after 48-96 h of incubation. Mechanistically, MIAP nano-formulation enhanced host defense mechanism by averting bacteria-induced inhibition of phagosomal-lysosome fusion (Lysostracker) and apoptosis (Annexin-FITC) as shown by confocal microscopy and flow-cytometry. Encapsulated MIAP may serve for adjunctive host-directed TB therapy which may also synergizes the efficacy of standard anti-TB drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

CuO nanoparticles encapsulated inside Al-MCM-41 mesoporous materials via direct synthetic route

PubMed Central

Huo, Chengli; Ouyang, Jing; Yang, Huaming

2014-01-01

Highly ordered aluminum-containing mesoporous silica (Al-MCM-41) was prepared using attapulgite clay mineral as a Si and Al source. Mesoporous complexes embedded with CuO nanoparticles were subsequently prepared using various copper sources and different copper loadings in a direct synthetic route. The resulting CuO/Al-MCM-41 composite possessed p6mm hexagonally symmetry, well-developed mesoporosity, and relatively high BET surface area. In comparison to pure silica, these mesoporous materials embedded with CuO nanoparticles exhibited smaller pore diameter, thicker pore wall, and enhanced thermal stability. Long-range order in the aforementioned samples was observed for copper weight percentages as high as 30%. Furthermore, a significant blue shift of the absorption edge for the samples was observed when compared with that of bulk CuO. H2-TPR measurements showed that the direct-synthesized CuO/Al-MCM-41 exhibited remarkable redox properties compared to the post-synthesized samples, and most of the CuO nanoparticles were encapsulated within the mesoporous structures. The possible interaction between CuO and Al-MCM-41 was also investigated. PMID:24419589

DNA hairpins promote temperature controlled cargo encapsulation in a truncated octahedral nanocage structure family

NASA Astrophysics Data System (ADS)

Franch, Oskar; Iacovelli, Federico; Falconi, Mattia; Juul, Sissel; Ottaviani, Alessio; Benvenuti, Claudia; Biocca, Silvia; Ho, Yi-Ping; Knudsen, Birgitta R.; Desideri, Alessandro

2016-07-01

In the present study we investigate the mechanism behind temperature controlled cargo uptake using a truncated octahedral DNA cage scaffold functionalized with one, two, three or four hairpin forming DNA strands inserted in one corner of the structure. This investigation was inspired by our previous demonstration of temperature controlled reversible encapsulation of the cargo enzyme, horseradish peroxidase, in the cage with four hairpin forming strands. However, in this previous study the mechanism of cargo uptake was not directly addressed (Juul, et al., Temperature-Controlled Encapsulation and Release of an Active Enzyme in the Cavity of a Self-Assembled DNA Nanocage, ACS Nano, 2013, 7, 9724-9734). In the present study we use a combination of molecular dynamics simulations and in vitro analyses to unravel the mechanism of cargo uptake in hairpin containing DNA cages. We find that two hairpin forming strands are necessary and sufficient to facilitate efficient cargo uptake, which argues against a full opening-closing of one corner of the structure being responsible for encapsulation. Molecular dynamics simulations were carried out to evaluate the atomistic motions responsible for encapsulation and showed that the two hairpin forming strands facilitated extension of at least one of the face surfaces of the cage scaffold, allowing entrance of the cargo protein into the cavity of the structure. Hence, the presented data demonstrate that cargo uptake does not involve a full opening of the structure. Rather, the uptake mechanism represents a feature of increased flexibility integrated in this nanocage structure upon the addition of at least two hairpin-forming strands.In the present study we investigate the mechanism behind temperature controlled cargo uptake using a truncated octahedral DNA cage scaffold functionalized with one, two, three or four hairpin forming DNA strands inserted in one corner of the structure. This investigation was inspired by our previous demonstration of temperature controlled reversible encapsulation of the cargo enzyme, horseradish peroxidase, in the cage with four hairpin forming strands. However, in this previous study the mechanism of cargo uptake was not directly addressed (Juul, et al., Temperature-Controlled Encapsulation and Release of an Active Enzyme in the Cavity of a Self-Assembled DNA Nanocage, ACS Nano, 2013, 7, 9724-9734). In the present study we use a combination of molecular dynamics simulations and in vitro analyses to unravel the mechanism of cargo uptake in hairpin containing DNA cages. We find that two hairpin forming strands are necessary and sufficient to facilitate efficient cargo uptake, which argues against a full opening-closing of one corner of the structure being responsible for encapsulation. Molecular dynamics simulations were carried out to evaluate the atomistic motions responsible for encapsulation and showed that the two hairpin forming strands facilitated extension of at least one of the face surfaces of the cage scaffold, allowing entrance of the cargo protein into the cavity of the structure. Hence, the presented data demonstrate that cargo uptake does not involve a full opening of the structure. Rather, the uptake mechanism represents a feature of increased flexibility integrated in this nanocage structure upon the addition of at least two hairpin-forming strands. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01806h

Mercury leaching from hazardous industrial wastes stabilized by sulfur polymer encapsulation.

PubMed

López, Félix A; Alguacil, Francisco J; Rodríguez, Olga; Sierra, María José; Millán, Rocío

2015-01-01

European Directive 2013/39/EU records mercury as a priority hazardous substance. Regulation n° 2008/1102/EC banned the exportation of mercury and required the safe storage of any remaining mercury compounds. The present work describes the encapsulation of three wastes containing combinations of HgS, HgSe, HgCl2, HgO2, Hg3Se2Cl2, HgO and Hg(0), according to patent of Spanish National Research Council WO2011/029970A2. The materials obtained were subjected to leaching tests according to standards UNE-EN-12457 and CEN/TS 14405:2004. The results are compared with the criteria established in the Council Decision 2003/33/EC for the acceptance of waste at landfills. The Hg concentrations of all leachates were <0.01mgHg/kg for a liquid/solid ratio of 10l/kg. All three encapsulated materials therefore meet the requirements for storage in inert waste landfills. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coaxial electrospinning for encapsulation and controlled release of fragile water-soluble bioactive agents.

PubMed

Jiang, Hongliang; Wang, Liqun; Zhu, Kangjie

2014-11-10

Coaxial electrospinning is a robust technique for one-step encapsulation of fragile, water-soluble bioactive agents, including growth factors, DNA and even living organisms, into core-shell nanofibers. The coaxial electrospinning process eliminates the damaging effects due to direct contact of the agents with organic solvents or harsh conditions during emulsification. The shell layer serves as a barrier to prevent the premature release of the water-soluble core contents. By varying the structure and composition of the nanofibers, it is possible to precisely modulate the release of the encapsulated agents. Promising work has been done with coaxially electrospun non-woven mats integrated with bioactive agents for use in tissue engineering, in local delivery and in wound healing, etc. This paper reviews the origins of the coaxial electrospinning method, its updated status and potential future developments for controlled release of the class of fragile, water-soluble bioactive agents. Copyright © 2014 Elsevier B.V. All rights reserved.

Electrical detection of ortho–para conversion in fullerene-encapsulated water

PubMed Central

Meier, Benno; Mamone, Salvatore; Concistrè, Maria; Alonso-Valdesueiro, Javier; Krachmalnicoff, Andrea; Whitby, Richard J.; Levitt, Malcolm H.

2015-01-01

Water exists in two spin isomers, ortho and para, that have different nuclear spin states. In bulk water, rapid proton exchange and hindered molecular rotation obscure the direct observation of two spin isomers. The supramolecular endofullerene H2O@C60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show that the bulk dielectric constant of this substance depends on the ortho/para ratio, and changes slowly in time after a sudden temperature jump, due to nuclear spin conversion. The attribution of the effect to ortho–para conversion is validated by comparison with nuclear magnetic resonance and quantum theory. The change in dielectric constant is consistent with an electric dipole moment of 0.51±0.05 Debye for an encapsulated water molecule, indicating the partial shielding of the water dipole by the encapsulating cage. The dependence of bulk dielectric constant on nuclear spin isomer composition appears to be a previously unreported physical phenomenon. PMID:26299447

Welding methods for joining thermoplastic polymers for the hermetic enclosure of medical devices.

PubMed

Amanat, Negin; James, Natalie L; McKenzie, David R

2010-09-01

New high performance polymers have been developed that challenge traditional encapsulation materials for permanent active medical implants. The gold standard for hermetic encapsulation for implants is a titanium enclosure which is sealed using laser welding. Polymers may be an alternative encapsulation material. Although many polymers are biocompatible, and permeability of polymers may be reduced to acceptable levels, the ability to create a hermetic join with an extended life remains the barrier to widespread acceptance of polymers for this application. This article provides an overview of the current techniques used for direct bonding of polymers, with a focus on thermoplastics. Thermal bonding methods are feasible, but some take too long and/or require two stage processing. Some methods are not suitable because of excessive heat load which may be delivered to sensitive components within the capsule. Laser welding is presented as the method of choice; however the establishment of suitable laser process parameters will require significant research. 2010. Published by Elsevier Ltd.

Cryopreservation of Arachis pintoi (leguminosae) somatic embryos.

PubMed

Rey, H Y; Faloci, M; Medina, R; Dolce, N; Engelmann, F; Mroginski, L

2013-01-01

In this study, we successfully cryopreserved cotyledonary somatic embryos of diploid and triploid Arachis pintoi cytotypes using the encapsulation-dehydration technique. The highest survival rates were obtained when somatic embryos were encapsulated in calcium alginate beads and precultured in agitated (80 rpm) liquid establishment medium (EM) with daily increasing sucrose concentration (0.50, 0.75, and 1.0 M). The encapsulated somatic embryos were then dehydrated with silica gel for 5 h to 20% moisture content (fresh weight basis) and cooled either rapidly (direct immersion in liquid nitrogen, LN) or slowly (1 degree C per min from 25 degree C to -30 degree C followed by immersion in LN). Beads were kept in LN for a minimum of 1 h and then were rapidly rewarmed in a 30 degree C water-bath for 2 min. Finally, encapsulated somatic embryos were post-cultured in agitated (80 rpm) liquid EM with daily decreasing sucrose concentration (0.75 and 0.5 M) and transferred to solidified EM. Using this protocol, we obtained 26% and 30% plant regeneration from cryopreserved somatic embryos of diploid and triploid cytotypes. No morphological abnormalities were observed in any of the plants regenerated from cryopreserved embryos and their genetic stability was confirmed with 10 isozyme systems and nine RAPD profiles.

Electronic nose screening of ethanol release during sol-gel encapsulation. A novel non-invasive method to test silica polymerisation.

PubMed

Lovino, Magalí; Cardinal, M Fernanda; Zubiri, Diana B V; Bernik, Delia L

2005-12-15

Porous silica matrices prepared by sol-gel process yield biocompatible materials adequate for encapsulation of biomolecules or drugs. The procedure is simple and fast, but when alkoxyde precursors like tetraethoxysilane (TEOS) are used the polymerisation reaction leads to the formation of alcohol as a by-product, which can produce undesirable effects on the activity of entrapped enzymes or modify a drug release kinetic. Therefore, it is critical to determine that no remnant ethanol is left prior using or storing the obtained biomaterial. In this regard, the technique used in the alcohol determination should be non-invasive and non-destructive to preserve the encapsulation device intact and ready to use. In this work we have successfully used a portable electronic nose (e-nose) for the screening of silica polymerisation process during theophylline encapsulation. TEOS reaction was "smelt" since precursor pre-hydrolysis until the end of ethanol release, sensed directly at the headspace of matrices slabs. Measurements showed that ethanol was negligible since 10th day in polymeric slabs of 10 mm width and 2 cm diameter. This first use of e-nose following a polymerisation reaction opens a wide number of putative applications in pharmaceutical and biochemical fields.

Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

NASA Astrophysics Data System (ADS)

Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

2018-04-01

Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

Titania nanotube arrays as potential interfaces for neurological prostheses

NASA Astrophysics Data System (ADS)

Sorkin, Jonathan Andrew

Neural prostheses can make a dramatic improvement for those suffering from visual and auditory, cognitive, and motor control disabilities, allowing them regained functionality by the use of stimulating or recording electrical signaling. However, the longevity of these devices is limited due to the neural tissue response to the implanted device. In response to the implant penetrating the blood brain barrier and causing trauma to the tissue, the body forms a to scar to isolate the implant in order to protect the nearby tissue. The scar tissue is a result of reactive gliosis and produces an insulated sheath, encapsulating the implant. The glial sheath limits the stimulating or recording capabilities of the implant, reducing its effectiveness over the long term. A favorable interaction with this tissue would be the direct adhesion of neurons onto the contacts of the implant, and the prevention of glial encapsulation. With direct neuronal adhesion the effectiveness and longevity of the device would be significantly improved. Titania nanotube arrays, fabricated using electrochemical anodization, provide a conductive architecture capable of altering cellular response. This work focuses on the fabrication of different titania nanotube array architectures to determine how their structures and properties influence the response of neural tissue, modeled using the C17.2 murine neural stem cell subclone, and if glial encapsulation can be reduced while neuronal adhesion is promoted.

Effect of Uniaxial Tensile Cyclic Loading Regimes on Matrix Organization and Tenogenic Differentiation of Adipose-Derived Stem Cells Encapsulated within 3D Collagen Scaffolds

PubMed Central

Stasuk, Alexander

2017-01-01

Adipose-derived mesenchymal stem cells have become a popular cell choice for tendon repair strategies due to their relative abundance, ease of isolation, and ability to differentiate into tenocytes. In this study, we investigated the solo effect of different uniaxial tensile strains and loading frequencies on the matrix directionality and tenogenic differentiation of adipose-derived stem cells encapsulated within three-dimensional collagen scaffolds. Samples loaded at 0%, 2%, 4%, and 6% strains and 0.1 Hz and 1 Hz frequencies for 2 hours/day over a 7-day period using a custom-built uniaxial tensile strain bioreactor were characterized in terms of matrix organization, cell viability, and musculoskeletal gene expression profiles. The results displayed that the collagen fibers of the loaded samples exhibited increased matrix directionality with an increase in strain values. Gene expression analyses demonstrated that ASC-encapsulated collagen scaffolds loaded at 2% strain and 0.1 Hz frequency showed significant increases in extracellular matrix genes and tenogenic differentiation markers. Importantly, no cross-differentiation potential to osteogenic, chondrogenic, and myogenic lineages was observed at 2% strain and 0.1 Hz frequency loading condition. Thus, 2% strain and 0.1 Hz frequency were identified as the appropriate mechanical loading regime to induce tenogenic differentiation of adipose-derived stem cells cultured in a three-dimensional environment. PMID:29375625

RBC micromotors carrying multiple cargos towards potential theranostic applications

NASA Astrophysics Data System (ADS)

Wu, Zhiguang; Esteban-Fernández de Ávila, Berta; Martín, Aída; Christianson, Caleb; Gao, Weiwei; Thamphiwatana, Soracha Kun; Escarpa, Alberto; He, Qiang; Zhang, Liangfang; Wang, Joseph

2015-08-01

Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic resonance imaging. The simultaneous encapsulation of the imaging nanoparticles and therapeutic payloads within the same RBC micromotor has a minimal effect upon its propulsion behavior. The ability of the RBC micromotors to transport imaging and therapeutic agents at high speed and spatial precision through a complex microchannel network is also demonstrated. Such ability to load and transport diagnostic imaging agents and therapeutic drugs within a single cell-based motor, in addition to a lower toxicity observed once the drug is encapsulated within the multicargo RBC motor, opens the door to the development of theranostic micromotors that may simultaneously treat and monitor diseases.Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic resonance imaging. The simultaneous encapsulation of the imaging nanoparticles and therapeutic payloads within the same RBC micromotor has a minimal effect upon its propulsion behavior. The ability of the RBC micromotors to transport imaging and therapeutic agents at high speed and spatial precision through a complex microchannel network is also demonstrated. Such ability to load and transport diagnostic imaging agents and therapeutic drugs within a single cell-based motor, in addition to a lower toxicity observed once the drug is encapsulated within the multicargo RBC motor, opens the door to the development of theranostic micromotors that may simultaneously treat and monitor diseases. Electronic supplementary information (ESI) available: Videos of the propulsion of the multicargo-loaded, RBC-based micromotors and more data are available in the ESI. See DOI: 10.1039/c5nr03730a

Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys.

PubMed

Lichter, Samantha G; Escudié, Mathilde C; Stacey, Alastair D; Ganesan, Kumaravelu; Fox, Kate; Ahnood, Arman; Apollo, Nicholas V; Kua, Dunstan C; Lee, Aaron Z; McGowan, Ceara; Saunders, Alexia L; Burns, Owen; Nayagam, David A X; Williams, Richard A; Garrett, David J; Meffin, Hamish; Prawer, Steven

2015-01-01

As the field of biomedical implants matures the functionality of implants is rapidly increasing. In the field of neural prostheses this is particularly apparent as researchers strive to build devices that interact with highly complex neural systems such as vision, hearing, touch and movement. A retinal implant, for example, is a highly complex device and the surgery, training and rehabilitation requirements involved in deploying such devices are extensive. Ideally, such devices will be implanted only once and will continue to function effectively for the lifetime of the patient. The first and most pivotal factor that determines device longevity is the encapsulation that separates the sensitive electronics of the device from the biological environment. This paper describes the realisation of a free standing device encapsulation made from diamond, the most impervious, long lasting and biochemically inert material known. A process of laser micro-machining and brazing is described detailing the fabrication of hermetic electrical feedthroughs and laser weldable seams using a 96.4% gold active braze alloy, another material renowned for biochemical longevity. Accelerated ageing of the braze alloy, feedthroughs and hermetic capsules yielded no evidence of corrosion and no loss of hermeticity. Samples of the gold braze implanted for 15 weeks, in vivo, caused minimal histopathological reaction and results were comparable to those obtained from medical grade silicone controls. The work described represents a first account of a free standing, fully functional hermetic diamond encapsulation for biomedical implants, enabled by gold active alloy brazing and laser micro-machining. Copyright © 2015 Elsevier Ltd. All rights reserved.

Survival of encapsulated islets: More than a membrane story

PubMed Central

Barkai, Uriel; Rotem, Avi; de Vos, Paul

2016-01-01

At present, proven clinical treatments but no cures are available for diabetes, a global epidemic with a huge economic burden. Transplantation of islets of Langerhans by their infusion into vascularized organs is an experimental clinical protocol, the first approach to attain cure. However, it is associated with lifelong use of immunosuppressants. To overcome the need for immunosuppression, islets are encapsulated and separated from the host immune system by a permselective membrane. The lead material for this application is alginate which was tested in many animal models and a few clinical trials. This review discusses all aspects related to the function of transplanted encapsulated islets such as the basic requirements from a permselective membrane (e.g., allowable hydrodynamic radii, implications of the thickness of the membrane and relative electrical charge). Another aspect involves adequate oxygen supply, which is essential for survival/performance of transplanted islets, especially when using large retrievable macro-capsules implanted in poorly oxygenated sites like the subcutis. Notably, islets can survive under low oxygen tension and are physiologically active at > 40 Torr. Surprisingly, when densely crowded, islets are fully functional under hyperoxic pressure of up to 500 Torr (> 300% of atmospheric oxygen tension). The review also addresses an additional category of requirements for optimal performance of transplanted islets, named auxiliary technologies. These include control of inflammation, apoptosis, angiogenesis, and the intra-capsular environment. The review highlights that curing diabetes with a functional bio-artificial pancreas requires optimizing all of these aspects, and that significant advances have already been made in many of them. PMID:27011906

Neural stem cells encapsulated in a functionalized self-assembling peptide hydrogel for brain tissue engineering.

PubMed

Cheng, Tzu-Yun; Chen, Ming-Hong; Chang, Wen-Han; Huang, Ming-Yuan; Wang, Tzu-Wei

2013-03-01

Brain injury is almost irreparable due to the poor regenerative capability of neural tissue. Nowadays, new therapeutic strategies have been focused on stem cell therapy and supplying an appropriate three dimensional (3D) matrix for the repair of injured brain tissue. In this study, we specifically linked laminin-derived IKVAV motif on the C-terminal to enrich self-assembling peptide RADA(16) as a functional peptide-based scaffold. Our purpose is providing a functional self-assembling peptide 3D hydrogel with encapsulated neural stem cells to enhance the reconstruction of the injured brain. The physiochemical properties reported that RADA(16)-IKVAV can self-assemble into nanofibrous morphology with bilayer β-sheet structure and become gelationed hydrogel with mechanical stiffness similar to brain tissue. The in vitro results showed that the extended IKVAV sequence can serve as a signal or guiding cue to direct the encapsulated neural stem cells (NSCs) adhesion and then towards neuronal differentiation. Animal study was conducted in a rat brain surgery model to demonstrate the damage in cerebral neocortex/neopallium loss. The results showed that the injected peptide solution immediately in situ formed the 3D hydrogel filling up the cavity and bridging the gaps. The histological analyses revealed the RADA(16)-IKVAV self-assembling peptide hydrogel not only enhanced survival of encapsulated NSCs but also reduced the formation of glial astrocytes. The peptide hydrogel with IKVAV extended motifs also showed the support of encapsulated NSCs in neuronal differentiation and the improvement in brain tissue regeneration after 6 weeks post-transplantation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Photoinitiated polymerization of PEG-diacrylate with lithium phenyl-2,4,6-trimethylbenzoylphosphinate: polymerization rate and cytocompatibility

PubMed Central

Fairbanks, Benjamin D.; Schwartz, Michael P.; Bowman, Christopher N.; Anseth, Kristi S.

2009-01-01

Due to mild reaction conditions and temporal and spatial control over material formation, photopolymerization has become a valuable technique for the encapsulation of living cells in three dimensional, hydrated, biomimetic materials. For such applications,2-hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (I2959) is the most commonly used photoinitiator (by virtue of its moderate water solubility), yet this initiator has an absorption spectrum that is poorly matched with wavelengths of light generally regarded as benign to living cells, limiting the rate at which it may initiate polymerization in their presence. In contrast, acylphosphine oxide photoinitiators, generally exhibit absorption spectra at wavelengths suitable for cell encapsulation, yet commercially available initiators of this class have low water solubility. Here, a water soluble lithium acylphosphinate salt is evaluated for its ability to polymerize diacrylated poly(ethylene glycol) (PEGDA) monomers rapidly into hydrogels, while maintaining high viability during direct encapsulation of cells. Through rheometric measurements, the time to reach gelation of a PEGDA solution with the phosphinate initiator is one tenth the time for that using I2959 at similar concentrations, when exposed to 365 nm light. Further, polymerization with the phosphinate initiator at 405 nm visible light exposure is achieved with low initiator concentrations and light intensities, precluded in polymerizations initiated with I2959 by its absorbance profile. When examined 24 hours after encapsulation, survival rates of human neonatal fibroblasts encapsulated in hydrogels polymerized with the phosphinate initiator exceed 95%, demonstrating the cytocompatibility of this initiating system. PMID:19783300

PLGA microspheres encapsulating siRNA.

PubMed

De Rosa, Giuseppe; Salzano, Giuseppina

2015-01-01

The therapeutic use of small interfering RNA (siRNA) represents a new and powerful approach to suppress the expression of pathologically genes. However, biopharmaceutical drawbacks, such as short half-life, poor cellular uptake, and unspecific distribution into the body, hamper the development of siRNA-based therapeutics. Poly(lactide-co-glycolide), (PLGA) microspheres can be a useful tool to overcome these issues. siRNA can be encapsulated into the PLGA microspheres, which protects the loaded nucleic acid against the enzymatic degradation. Moreover, PLGA microspheres can be injected directly into the action site, where the siRNA can be released in controlled manner, thus avoiding the need of frequent invasive administrations. The complete biodegradability of PLGA to monomers easily metabolized by the body, and its approval by FDA and EMA for parenteral administration, assure the safety of this copolymer and do not require the removal of the device after the complete drug release. In chapter, a basic protocol for the preparation of PLGA microspheres encapsulating siRNA is described. This protocol is based on a double emulsion/solvent evaporation technique, a well known and easy to reproduce method. This specific protocol has been developed to encapsulate a siRNA anti-TNFα in PLGA microspheres, and it has been designed and optimized to achieve high siRNA encapsulation efficiency and slow siRNA release in vitro. However, it can be extended also to other siRNA as well as other RNA or DNA-based oligonucleotides (miRNA, antisense, decoy, etc.). Depending on the applications, chemical modifications of the backbone and site-specific modification within the siRNA sequences could be required.

Artificial inorganic biohybrids: The functional combination of microorganisms and cells with inorganic materials.

PubMed

Holzmeister, Ib; Schamel, Martha; Groll, Jürgen; Gbureck, Uwe; Vorndran, Elke

2018-04-24

Biohybrids can be defined as the functional combination of proteins, viable cells or microorganisms with non-biological materials. This article reviews recent findings on the encapsulation of microorganisms and eukaryotic cells in inorganic matrices such as silica gels or cements. The entrapment of biological entities into a support material is of great benefit for processing since the encapsulation matrix protects sensitive cells from shear forces, unfavourable pH changes, or cytotoxic solvents, avoids culture-washout, and simplifies the separation of formed products. After reflecting general aspects of such an immobilization as well as the chemistry of the inorganic matrices, we focused on manufacturing aspects and the application of such biohybrids in biotechnology, medicine as well as in environmental science and for civil engineering purpose. The encapsulation of living cells and microorganisms became an intensively studied and rapidly expanding research field with manifold applications in medicine, bio- and environmental technology, or civil engineering. Here, the use of silica or cements as encapsulation matrices have the advantage of a higher chemical and mechanical resistance towards harsh environmental conditions during processing compared to their polymeric counterparts. In this perspective, the article gives an overview about the inorganic material systems used for cell encapsulation, followed by reviewing the most important applications. The future may lay in a combination of the currently achieved biohybrid systems with additive manufacturing techniques. In a longer perspective, this would enable the direct printing of cell loaded bioreactor components. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Synthesis and application of hydroxyapatite and fluoroapatite to scorodite encapsulation

NASA Astrophysics Data System (ADS)

Katsarou, Lydia

Recent research has investigated the precipitation of crystalline scorodite (FeAsO4˙2H2O) as a method to stabilise arsenic for disposal due to its good stability performance according to EPA's TCLP test. It has been determined, however, that scorodite releases arsenic in significant concentrations under alkaline pH or under anoxic conditions. With the objective of enhancing the stability of scorodite, its encapsulation with minerals inert to pH and redox potential variations is considered in this work. Such encapsulation materials are hydroxyapatite (HAP-Ca5(PO4)3OH) and fluoroapatite (FAP-Ca5(PO4)3F), the two most stable of the calcium phosphates. The work described in this thesis includes: 1) the preparation of hydroxyapatite and fluoroapatite powders and their characterisation, 2) the synthesis of crystalline scorodite under atmospheric conditions and its characterisation, 3) the encapsulation of scorodite with hydroxyapatite and fluoroapatite, and 4) the long term stability testing of the encapsulated solids. Hydroxyapatite and fluoroapatite were prepared first by homogeneous precipitation from a metastable solution, to which "Ca" and "PO4" source reagents of different concentrations were added at variable rates. The crystallinity of the produced materials was found to increase with temperature. Crystalline scorodite was produced by seeded crystallisation in ambient pressure. For the encapsulation of the scorodite particles various methods of direct precipitation by controlled supersaturation were attempted, by adjusting the pH and adding/mixing feed solutions of individual calcium and phosphate source reagents. Heterogeneous deposition of HAP on scorodite proved rather difficult. Optimum results were obtained via prior conditioning of the scorodite substrate in a calcium solution and employment of low agitation regime and high (37 °C rather than 22°C) temperature. The stability tests were done in oxic and anoxic environments and their results demonstrated that the encapsulated solids had enhanced stability, since the release of arsenic was lower than it was for naked scorodite. The presence of gypsum was found to help reduce the release of arsenic further as well as phosphorus under oxic, but not anoxic conditions due to possible interaction with the sulphite ions used as reducing agent.

Solution NMR spectroscopy of food polysaccharides

USDA-ARS?s Scientific Manuscript database

Many polysaccharides are allowed for direct food use, where they serve a number of useful functions. In addition to possibly being a source of calories, a food polysaccharide may be a dietary fiber, bulking agent, crystallization inhibitor, thickener, encapsulant, gelling agent, foam and emulsion s...

GOES-S Encapsulation

NASA Image and Video Library

2018-02-07

In a clean room at Astrotech Space Operations in Titusville, Florida, technicians and engineers monitor progress as NOAA's Geostationary Operational Environmental Satellite-S, or GOES-S, is encapsulated in its payload fairing. It soon will be moved to Space Launch Complex 41 at Cape Canaveral Air Force Station for mounting atop the Atlas V rocket that will boost the satellite to orbit. GOES-S is the second in a series of four advanced geostationary weather satellites that will significantly improve the detection and observation of environmental phenomena that directly affect public safety, protection of property and the nation's economic health and prosperity. GOES-S is slated to launch March 1, 2018 aboard a United Launch Alliance Atlas V rocket.

Unique Proton Transportation Pathway in a Robust Inorganic Coordination Polymer Leading to Intrinsically High and Sustainable Anhydrous Proton Conductivity.

PubMed

Gui, Daxiang; Dai, Xing; Tao, Zetian; Zheng, Tao; Wang, Xiangxiang; Silver, Mark A; Shu, Jie; Chen, Lanhua; Wang, Yanlong; Zhang, Tiantian; Xie, Jian; Zou, Lin; Xia, Yuanhua; Zhang, Jujia; Zhang, Jin; Zhao, Ling; Diwu, Juan; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

2018-05-16

Although comprehensive progress has been made in the area of coordination polymer (CP)/metal-organic framework (MOF)-based proton-conducting materials over the past decade, searching for a CP/MOF with stable, intrinsic, high anhydrous proton conductivity that can be directly used as a practical electrolyte in an intermediate-temperature proton-exchange membrane fuel cell assembly for durable power generation remains a substantial challenge. Here, we introduce a new proton-conducting CP, (NH 4 ) 3 [Zr(H 2/3 PO 4 ) 3 ] (ZrP), which consists of one-dimensional zirconium phosphate anionic chains and fully ordered charge-balancing NH 4 + cations. X-ray crystallography, neutron powder diffraction, and variable-temperature solid-state NMR spectroscopy suggest that protons are disordered within an inherent hydrogen-bonded infinite chain of acid-base pairs (N-H···O-P), leading to a stable anhydrous proton conductivity of 1.45 × 10 -3 S·cm -1 at 180 °C, one of the highest values among reported intermediate-temperature proton-conducting materials. First-principles and quantum molecular dynamics simulations were used to directly visualize the unique proton transport pathway involving very efficient proton exchange between NH 4 + and phosphate pairs, which is distinct from the common guest encapsulation/dehydration/superprotonic transition mechanisms. ZrP as the electrolyte was further assembled into a H 2 /O 2 fuel cell, which showed a record-high electrical power density of 12 mW·cm -2 at 180 °C among reported cells assembled from crystalline solid electrolytes, as well as a direct methanol fuel cell for the first time to demonstrate real applications. These cells were tested for over 15 h without notable power loss.

A 32-channel fully implantable wireless neurosensor for simultaneous recording from two cortical regions.

PubMed

Aceros, Juan; Yin, Ming; Borton, David A; Patterson, William R; Nurmikko, Arto V

2011-01-01

We present a fully implantable, wireless, neurosensor for multiple-location neural interface applications. The device integrates two independent 16-channel intracortical microelectrode arrays and can simultaneously acquire 32 channels of broadband neural data from two separate cortical areas. The system-on-chip implantable sensor is built on a flexible Kapton polymer substrate and incorporates three very low power subunits: two cortical subunits connected to a common subcutaneous subunit. Each cortical subunit has an ultra-low power 16-channel preamplifier and multiplexer integrated onto a cortical microelectrode array. The subcutaneous epicranial unit has an inductively coupled power supply, two analog-to-digital converters, a low power digital controller chip, and microlaser-based infrared telemetry. The entire system is soft encapsulated with biocompatible flexible materials for in vivo applications. Broadband neural data is conditioned, amplified, and analog multiplexed by each of the cortical subunits and passed to the subcutaneous component, where it is digitized and combined with synchronization data and wirelessly transmitted transcutaneously using high speed infrared telemetry.

KSC-03pd0163

NASA Image and Video Library

2003-01-16

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Purpose Processing Facility check the fairing placed around the Solar Radiation and Climate Experiment (SORCE) satellite. When fully encapsulated, the satellite will be installed in the Pegasus XL launch vehicle. Built by Orbital Sciences Corporation (OSC), SORCE will study and measure solar irradiance as a source of energy in the Earth's atmosphere. The launch of SORCE is scheduled for Jan. 25 at 3:14 p.m. from Cape Canaveral Air Force Station, Fla. The drop of the Pegasus will be from OSC's L-1011 aircraft at an altitude of 39,000 feet over the Atlantic Ocean approximately 100 miles east-southeast of Cape Canaveral.

Encapsulation of enzyme via one-step template-free formation of stable organic-inorganic capsules: A simple and efficient method for immobilizing enzyme with high activity and recyclability.

PubMed

Huang, Renliang; Wu, Mengyun; Goldman, Mark J; Li, Zhi

2015-06-01

Enzyme encapsulation is a simple, gentle, and general method for immobilizing enzyme, but it often suffers from one or more problems regarding enzyme loading efficiency, enzyme leakage, mechanical stability, and recyclability. Here we report a novel, simple, and efficient method for enzyme encapsulation to overcome these problems by forming stable organic-inorganic hybrid capsules. A new, facile, one-step, and template-free synthesis of organic-inorganic capsules in aqueous phase were developed based on PEI-induced simultaneous interfacial self-assembly of Fmoc-FF and polycondensation of silicate. Addition of an aqueous solution of Fmoc-FF and sodium silicate into an aqueous solution of PEI gave a new class of organic-inorganic hybrid capsules (FPSi) with multi-layered structure in high yield. The capsules are mechanically stable due to the incorporation of inorganic silica. Direct encapsulation of enzyme such as epoxide hydrolase SpEH and BSA along with the formation of the organic-inorganic capsules gave high yield of enzyme-containing capsules (∼1.2 mm in diameter), >90% enzyme loading efficiency, high specific enzyme loading (158 mg protein g(-1) carrier), and low enzyme leakage (<3% after 48 h incubation). FPSi-SpEH capsules catalyzed the hydrolysis of cyclohexene oxide to give (1R, 2R)-cyclohexane-1,2-diol in high yield and concentration, with high specific activity (6.94 U mg(-1) protein) and the same high enantioselectivity as the free enzyme. The immobilized SpEH demonstrated also excellent operational stability and recyclability: retaining 87% productivity after 20 cycles with a total reaction time of 80 h. The new enzyme encapsulation method is efficient, practical, and also better than other reported encapsulation methods. © 2015 Wiley Periodicals, Inc.

Poly(dodecyl methacrylate) as solvent of paraffins for phase change materials and thermally reversible light scattering films.

PubMed

Puig, Julieta; Williams, Roberto J J; Hoppe, Cristina E

2013-09-25

Paraffins are typical organic phase change materials (PCM) used for latent heat storage. For practical applications they must be encapsulated to prevent leakage or agglomeration during fusion. In this study it is shown that eicosane (C20H42 = C20) in the melted state could be dissolved in the hydrophobic domains of poly(dodecyl methacrylate) (PDMA) up to concentrations of 30 wt %, avoiding the need of encapsulation. For a 30 wt % solution, the heat of phase change was close to 69 J/g, a reasonable value for its use as a PCM. The fully converted solution remained transparent at 80 °C with no evidence of phase separation but became opaque by cooling as a consequence of paraffin crystallization. Heating above the melting temperature regenerated a transparent material. A high contrast ratio and abrupt transition between opaque and transparent states was observed for the 30 wt % blends, with a transparent state at 35 °C and an opaque state at 23 °C. This behavior was completely reproducible during consecutive heating/cooling cycles, indicating the possible use of this material as a thermally reversible light scattering (TRLS) film.

Flight Performance Feasibility Studies for the Max Launch Abort System

NASA Technical Reports Server (NTRS)

Tarabini, Paul V.; Gilbert, Michael G.; Beaty, James R.

2013-01-01

In 2007, the NASA Engineering and Safety Center (NESC) initiated the Max Launch Abort System Project to explore crew escape system concepts designed to be fully encapsulated within an aerodynamic fairing and smoothly integrated onto a launch vehicle. One objective of this design was to develop a more compact launch escape vehicle that eliminated the need for an escape tower, as was used in the Mercury and Apollo escape systems and what is planned for the Orion Multi-Purpose Crew Vehicle (MPCV). The benefits for the launch vehicle of eliminating a tower from the escape vehicle design include lower structural weights, reduced bending moments during atmospheric flight, and a decrease in induced aero-acoustic loads. This paper discusses the development of encapsulated, towerless launch escape vehicle concepts, especially as it pertains to the flight performance and systems analysis trade studies conducted to establish mission feasibility and assess system-level performance. Two different towerless escape vehicle designs are discussed in depth: one with allpropulsive control using liquid attitude control thrusters, and a second employing deployable aft swept grid fins to provide passive stability during coast. Simulation results are presented for a range of nominal and off-nominal escape conditions.

Microencapsulation for the Therapeutic Delivery of Drugs, Live Mammalian and Bacterial Cells, and Other Biopharmaceutics: Current Status and Future Directions

PubMed Central

Saha, Shyamali; Malhotra, Meenakshi; Kahouli, Imen; Prakash, Satya

2013-01-01

Microencapsulation is a technology that has shown significant promise in biotherapeutics, and other applications. It has been proven useful in the immobilization of drugs, live mammalian and bacterial cells and other cells, and other biopharmaceutics molecules, as it can provide material structuration, protection of the enclosed product, and controlled release of the encapsulated contents, all of which can ensure efficient and safe therapeutic effects. This paper is a comprehensive review of microencapsulation and its latest developments in the field. It provides a comprehensive overview of the technology and primary goals of microencapsulation and discusses various processes and techniques involved in microencapsulation including physical, chemical, physicochemical, and other methods involved. It also summarizes the state-of-the-art successes of microencapsulation, specifically with regard to the encapsulation of microorganisms, mammalian cells, drugs, and other biopharmaceutics in various diseases. The limitations and future directions of microencapsulation technologies are also discussed. PMID:26555963

Direct Hydrogel Encapsulation of Pluripotent Stem Cells Enables Ontomimetic Differentiation and Growth of Engineered Human Heart Tissues

PubMed Central

Kerscher, Petra; Turnbull, Irene C; Hodge, Alexander J; Kim, Joonyul; Seliktar, Dror; Easley, Christopher J; Costa, Kevin D; Lipke, Elizabeth A

2016-01-01

Human engineered heart tissues have potential to revolutionize cardiac development research, drug-testing, and treatment of heart disease; however, implementation is limited by the need to use pre-differentiated cardiomyocytes (CMs). Here we show that by providing a 3D poly(ethylene glycol)-fibrinogen hydrogel microenvironment, we can directly differentiate human pluripotent stem cells (hPSCs) into contracting heart tissues. Our straight-forward, ontomimetic approach, imitating the process of development, requires only a single cell-handling step, provides reproducible results for a range of tested geometries and size scales, and overcomes inherent limitations in cell maintenance and maturation, while achieving high yields of CMs with developmentally appropriate temporal changes in gene expression. Here we demonstrate that hPSCs encapsulated within this biomimetic 3D hydrogel microenvironment develop into functional cardiac tissues composed of self-aligned CMs with evidence of ultrastructural maturation, mimicking heart development, and enabling investigation of disease mechanisms and screening of compounds on developing human heart tissue. PMID:26826618

Identifying lipidic emulsomes for improved oxcarbazepine brain targeting: In vitro and rat in vivo studies.

PubMed

El-Zaafarany, Ghada M; Soliman, Mahmoud E; Mansour, Samar; Awad, Gehanne A S

2016-04-30

Lipid-based nanovectors offer effective carriers for brain delivery by improving drug potency and reducing off-target effects. Emulsomes are nano-triglyceride (TG) carriers formed of lipid cores supported by at least one phospholipid (PC) sheath. Due to their surface active properties, PC forms bilayers at the aqueous interface, thereby enabling encapsulated drug to benefit from better bioavailability and stability. Emulsomes of oxcarbazepine (OX) were prepared, aimed to offer nanocarriers for nasal delivery for brain targeting. Different TG cores (Compritol(®), tripalmitin, tristearin and triolein) and soya phosphatidylcholine in different amounts and ratios were used for emulsomal preparation. Particles were modulated to generate nanocarriers with suitable size, charge, encapsulation efficiency and prolonged release. Cytotoxicity and pharmacokinetic studies were also implemented. Nano-spherical OX-emulsomes with maximal encapsulation of 96.75% were generated. Stability studies showed changes within 30.6% and 11.2% in the size and EE% after 3 months. MTT assay proved a decrease in drug toxicity by its encapsulation in emulsomes. Incorporation of OX into emulsomes resulted in stable nanoformulations. Tailoring emulsomes properties by modulating the surface charge and particle size produced a stable system for the lipophilic drug with a prolonged release profile and mean residence time and proved direct nose-to-brain transport in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

pH and Amphiphilic Structure Direct Supramolecular Behavior in Biofunctional Assemblies

DOE PAGES

Moyer, Tyson J.; Finbloom, Joel A.; Chen, Feng; ...

2014-10-13

Supramolecular self-assembly offers promising new ways to control nanostructure morphology and respond to external stimuli. A pH-sensitive self-assembled system was developed to both control nanostructure shape and respond to the acidic microenvironment of tumors using self-assembling peptide amphiphiles (PAs). Here, by incorporating an oligo-histidine H 6 sequence, we developed two PAs that self-assembled into distinct morphologies on the nanoscale, either as nanofibers or spherical micelles, based on the incorporation of the aliphatic tail on the N-terminus or near the C-terminus, respectively. Both cylinder and sphere-forming PAs demonstrated reversible disassembly between pH 6.0 and 6.5 upon protonation of the histidine residuesmore » in acidic solutions. These PAs were then characterized and assessed for their potential to encapsulate hydrophobic chemotherapies. The H 6-based nanofiber assemblies encapsulated camptothecin (CPT) with up to 60% efficiency, a 7-fold increase in CPT encapsulation relative to spherical micelles. Additionally, pH-sensitive nanofibers showed improved tumor accumulation over both spherical micelles and nanofibers that did not change morphologies in acidic environments. We have demonstrated that the morphological transitions upon changes in pH of supramolecular nanostructures affect drug encapsulation and tumor accumulation. Lastly, our findings also suggest that these supramolecular events can be tuned by molecular design to improve the pharmacologic properties of nanomedicines.« less

Incorporation of liposomes containing squid tunic ACE-inhibitory peptides into fish gelatin.

PubMed

Mosquera, Mauricio; Giménez, Begoña; Montero, Pilar; Gómez-Guillén, Maria Carmen

2016-02-01

Hydrolysates from collagen of jumbo squid (Dosidicus gigas) tunics have shown excellent angiotensin I-converting enzyme (ACE)-inhibitory activity. However, peptides directly included in food systems may suffer a decrease in activity, which could be minimized by loading them into nanoliposomes. A fraction of peptides with molecular weights <1 kDa obtained from hydrolyzed squid tunics, with reasonably high ACE-inhibitory activity (half-maximal inhibitory concentration IC50 = 0.096 g L(-1)), was encapsulated in phosphatidylcholine nanoliposomes. The peptide concentration affected the encapsulation efficiency and the stability of the resulting liposomes, which remained with a high zeta potential value (-54.3 mV) for at least 1 week at the most suitable peptide concentration. The optimal peptide concentration was established as 1.75 g L(-1). Liposomes obtained with this peptide concentration showed an encapsulation efficiency of 53%, a zeta potential of -59 mV, an average diameter of 70.3 nm and proved to be stable in the pH range 3-7 at 4 °C. Liposomes containing ACE-inhibitory peptides were incorporated in fish gelatin without detriment to the rheological properties and thermal stability of the resulting cold-induced gel. The ACE-inhibitory activity of the peptide fraction, which was not affected by the encapsulation process, conferred the bioactive potential to the nanoliposome-containing gelatin gel. © 2015 Society of Chemical Industry.

Calcium sulfoaluminate cement blended with OPC: A potential binder to encapsulate low-level radioactive slurries of complex chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cau Dit Coumes, Celine; Courtois, Simone; Peysson, Sandrine

Investigations were carried out in order to solidify in cement a low-level radioactive waste of complex chemistry obtained by mixing two process streams, a slurry produced by ultra-filtration and an evaporator concentrate with a salinity of 600 gxL{sup -1}. Direct cementation with Portland cement (OPC) was not possible due to a very long setting time of cement resulting from borates and phosphates contained in the waste. According to a classical approach, this difficulty could be solved by pre-treating the waste to reduce adverse cement-waste interactions. A two-stage process was defined, including precipitation of phosphates and sulfates at 60 deg. Cmore » by adding calcium and barium hydroxide to the waste stream, and encapsulation with a blend of OPC and calcium aluminate cement (CAC) to convert borates into calcium quadriboroaluminate. The material obtained with a 30% waste loading complied with specifications. However, the pre-treatment step made the process complex and costly. A new alternative was then developed: the direct encapsulation of the waste with a blend of OPC and calcium sulfoaluminate cement (CSA) at room temperature. Setting inhibition was suppressed, which probably resulted from the fact that, when hydrating, CSA cement formed significant amounts of ettringite and calcium monosulfoaluminate hydrate which incorporated borates into their structure. As a consequence, the waste loading could be increased to 56% while keeping acceptable properties at the laboratory scale.« less

Chitosan Enriched Three-Dimensional Matrix Reduces Inflammatory and Catabolic Mediators Production by Human Chondrocytes

PubMed Central

Oprenyeszk, Frederic; Sanchez, Christelle; Dubuc, Jean-Emile; Maquet, Véronique; Henrist, Catherine; Compère, Philippe; Henrotin, Yves

2015-01-01

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for 28 days either in chitosan-alginate beads or in alginate beads. The beads were formed by slowly passing dropwise either the chitosan 0.6%–alginate 1.2% or the alginate 1.2% solution through a syringe into a 102 mM CaCl2 solution. Beads were analyzed histologically after 28 days. Interleukin (IL)-6 and -8, prostaglandin (PG) E2, matrix metalloproteinases (MMPs), hyaluronan and aggrecan were quantified directly in the culture supernatant by specific ELISA and nitric oxide (NO) by using a colorimetric method based on the Griess reaction. Hematoxylin and eosin staining showed that chitosan was homogeneously distributed through the matrix and was in direct contact with chondrocytes. The production of IL-6, IL-8 and MMP-3 by chondrocytes significantly decreased in chitosan-alginate beads compared to alginate beads. PGE2 and NO decreased also significantly but only during the first three days of culture. Hyaluronan and aggrecan production tended to increase in chitosan-alginate beads after 28 days of culture. Chitosan-alginate beads reduced the production of inflammatory and catabolic mediators by OA chondrocytes and tended to stimulate the synthesis of cartilage matrix components. These particular effects indicate that chitosan-alginate beads are an interesting scaffold for chondrocytes encapsulation before transplantation to repair cartilage defects. PMID:26020773

Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo

NASA Astrophysics Data System (ADS)

Gou, Maling; Men, Ke; Shi, Huashan; Xiang, Mingli; Zhang, Juan; Song, Jia; Long, Jianlin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, Zhiyong

2011-04-01

Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 +/- 0.011) with a mean particle size of 27.3 +/- 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 +/- 1.02%, and drug loading of 12.95 +/- 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t1/2 and AUC of curcuminin vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesisin vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cellsin vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg-1curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

The t-PA-encapsulated PLGA nanoparticles shelled with CS or CS-GRGD alter both permeation through and dissolving patterns of blood clots compared with t-PA solution: an in vitro thrombolysis study.

PubMed

Wang, Shoei-Shen; Chou, Nai-Kuan; Chung, Tze-Wen

2009-12-01

Accelerated thrombolysis by pressure-driven permeation has been demonstrated in in vitro and in vivo animal models by using plasminogen activators (PAs) encapsulated liposomes or PEG microparticles. Recent reports have also described acceleration of thrombolysis using tissue type PA (t-PA) encapsulated in PLGA nanoparticles (NPs) coated with chitosan (CS) or CS-GRGD by interactions between the NPs and blood clots. However, the permeation through and dissolving patterns in thrombolysis with the aforementioned microparticles or NPs, which may be clinically relevant to the recovery status of the posttreatments, have not been reported. Therefore, this work studied such phenomena in thrombolysis with t-PA encapsulated in NPs. The t-PA solution and the NPs exhibited distinctly different permeation patterns of dissolved clots. Plasma permeates through clots showed a stream flow or burst flow phenomena when lyzed with NPs shelled with CS or CS-GRGD, respectively, whereas a diffusion pattern was observed in those lyzed with t-PA solution. At the outlet position of clots, the clots dissolved with PLGA/CS and PLGA/CS-GRGD NPs revealed extremely rough surfaces to a depth of 100 mum, indicating that a cross-permeation direction of clot lysis occurred, while those dissolved with t-PA solution showed slightly rough surfaces to a depth of 12 mum. Permeation through and clot dissolution patterns of thrombolysis with t-PA encapsulated in NPs shelled with CS or CS-GRGD distinctly differed from those dissolved with t-PA solutions in this in vitro thrombolysis model, These findings may be relevant to posttreatment of patients with conventional PA thrombolysis. Copyright 2008 Wiley Periodicals, Inc.

Anti-botulism single-shot vaccine using chitosan for protein encapsulation by simple coacervation.

PubMed

Sari, Roger S; de Almeida, Anna Christina; Cangussu, Alex S R; Jorge, Edson V; Mozzer, Otto D; Santos, Hércules Otacílio; Quintilio, Wagner; Brandi, Igor Viana; Andrade, Viviane Aguiar; Miguel, Angelo Samir M; Sobrinho Santos, Eliane M

2016-12-01

The aim of the present study was to compare the potency and safety of vaccines against Clostridium botulinum (C. botulinum) type C and D formulated with chitosan as controlled release matrix and vaccines formulated in conventional manner using aluminum hydroxide. Parameters were established for the development of chitosan microspheres, using simple coacervation to standardize the use of this polymer in protein encapsulation for vaccine formulation. To formulate a single shot vaccine inactivated antigens of C. botulinum type C and D were used with original toxin titles equal to 5.2 and 6.2 log LD50/ml, respectively. For each antigen a chitosan based solution of 50 mL was prepared. Control vaccines were formulated by mixing toxoid type C and D with aluminum hydroxide [25% Al(OH) 3 , pH 6.3]. The toxoid sterility, innocuity and potency of vaccines were evaluated as stipulated by MAPA-BRASIL according to ministerial directive no. 23. Encapsulation efficiency of BSA in chitosan was 32.5-40.37%, while that the encapsulation efficiency to toxoid type C was 41,03% (1.94 mg/mL) and of the toxoid type D was 32.30% (1.82 mg/mL). The single shot vaccine formulated using chitosan for protein encapsulation through simple coacervation showed potency and safety similar to conventional vaccine currently used in Brazilian livestock (10 and 2 IU/mL against C. botulinum type C and D, respectively). The present work suggests that our single shot vaccine would be a good option as a cattle vaccine against these C. botulinum type C and D. Copyright © 2016 Elsevier Ltd. All rights reserved.

Safety and efficacy of encapsulated fecal microbiota transplantation for recurrent Clostridium difficile infection: a systematic review.

PubMed

Iqbal, Umair; Anwar, Hafsa; Karim, Muhammad A

2018-07-01

Fecal microbial transplantation (FMT) has been shown to be effective for the treatment of recurrent clostridium difficile infection (CDI). The efficacy and safety of freeze-dried encapsulated FMT for the treatment of recurrent CDI is unclear. We performed a systematic review to evaluate and analyze the current evidence in this respect. A systematic literature search was performed using the PubMed, Embase, and Medline databases until December 2017 to identify all original studies that investigated the role of administration of encapsulated FMT in recurrent CDI. The study included patients of all ages. Two independent reviewers extracted data and assessed the quality of publications; a third investigator resolved any discrepancies. A total of six studies, five case series and one randomized-controlled trial, were included in this review. Overall, 341 patients completed treatment with encapsulated FMT. Only three major adverse events were reported and no deaths occurred directly related to FMT. In all, 285 patients responded to the first treatment, with no recurrence during the specified follow-up period set to meet the primary endpoint. Forty-two patients underwent a second treatment, with resolution of symptoms in 28 patients. At least five patients were reported to undergo a third treatment, with resolution in three of them. Only one patient was reported to have received four treatments without long-term resolution of symptoms. Low-quality to moderate-quality evidence showed that encapsulated FMT is safe and cost-effective for the treatment and prevention of recurrent CDI. Its efficacy is not inferior to FMT performed through the nonoral route. Randomized-controlled trials are necessary to compare its efficacy with oral antimicrobial drugs and also to evaluate the potential adverse effects associated with the treatment.

Pancreatic Tissue Transplanted in TheraCyte Encapsulation Devices Is Protected and Prevents Hyperglycemia in a Mouse Model of Immune-Mediated Diabetes.

PubMed

Boettler, Tobias; Schneider, Darius; Cheng, Yang; Kadoya, Kuniko; Brandon, Eugene P; Martinson, Laura; von Herrath, Matthias

2016-01-01

Type 1 diabetes (T1D) is characterized by destruction of glucose-responsive insulin-producing pancreatic β-cells and exhibits immune infiltration of pancreatic islets, where CD8 lymphocytes are most prominent. Curative transplantation of pancreatic islets is seriously hampered by the persistence of autoreactive immune cells that require high doses of immunosuppressive drugs. An elegant approach to confer graft protection while obviating the need for immunosuppression is the use of encapsulation devices that allow for the transfer of oxygen and nutrients, yet prevent immune cells from making direct contact with the islet grafts. Here we demonstrate that macroencapsulation devices (TheraCyte) loaded with neonatal pancreatic tissue and transplanted into RIP-LCMV.GP mice prevented disease onset in a model of virus-induced diabetes mellitus. Histological analyses revealed that insulin-producing cells survived within the device in animal models of diabetes. Our results demonstrate that these encapsulation devices can protect from an immune-mediated attack and can contain a sufficient amount of insulin-producing cells to prevent overt hyperglycemia.

Enhanced cytotoxicity of anticancer drug delivered by novel nanoscale polymeric carrier

NASA Astrophysics Data System (ADS)

Stoika, R.; Boiko, N.; Senkiv, Y.; Shlyakhtina, Y.; Panchuk, R.; Finiuk, N.; Filyak, Y.; Bilyy, R.; Kit, Y.; Skorohyd, N.; Klyuchivska, O.; Zaichenko, A.; Mitina, N.; Ryabceva, A.

2013-04-01

We compared in vitro action of highly toxic anticancer drug doxorubicin under its delivery to the mammalian tumor cells in free form and after encapsulation in novel bio-functionalized nanoscale polymeric carrier. Such encapsulation was found to enhance significantly drug uptake by the targeted cells, as well as its cytotoxic action. 10 times higher cytotoxicity of the carrier-immobilized doxorubicin comparing to its free form was demonstrated by direct cell counting, and 5 times higher cytotoxicity of encapsulated doxorubicin was shown by FACS analysis. The polymeric carrier itself did not possess significant toxicity in vitro or in vivo (laboratory mice). The carrier protected against negative side effects of doxorubicin in mice with experimental NK/Ly lymphoma. The life duration of tumor-bearing animals treated with doxorubicin-carrier complex was significantly longer than life duration in animals treated with free doxorubicin. Besides, the effective treatment dose of the carrier-delivered doxorubicin in tumor-bearing mice was 10 times lower than such dose of free doxorubicin. Thus, novel nanoscale polymers possess high potential as drug carrier.

Elevating bioavailability of cyclosporine a via encapsulation in artificial oil bodies stabilized by caleosin.

PubMed

Chen, Miles C M; Wang, Jui-Ling; Tzen, Jason T C

2005-01-01

To elevate its bioavailability via oral administration, cyclosporine A (CsA), a hydrophobic drug, was either incorporated into olive oil directly or encapsulated in artificial oil bodies (AOBs) constituted with olive oil and phospholipid in the presence or absence of recombinant caleosin purified from Escherichia coli. The bioavailabilities of CsA in these formulations were assessed in Wistar rats in comparison with the commercial formulation, Sandimmun Neoral. Among these tests, CsA-loaded AOBs stabilized by the recombinant caleosin exhibited better bioavailability than the commercial formulation and possessed the highest maximum whole blood concentration (C(max)), 1247.4 +/- 106.8 ng/mL, in the experimental animals 4.3 +/- 0.7 h (t(max)) after oral administration. C(max) and the area under the plasma concentration-time curve (AUC(0-24)) were individually increased by 50.8% and 71.3% in the rats fed with caleosin-stabilized AOBs when compared with those fed with the reference Sandimmun Neoral. The results suggest that constitution of AOBs stabilized by caleosin may be a suitable technique to encapsulate hydrophobic drugs for oral administration.

Enhanced International Space Station Ku-Band Telemetry Service

NASA Technical Reports Server (NTRS)

Cecil, Andrew J.; Pitts, R. Lee; Welch, Steven J.; Bryan, Jason D.

2014-01-01

The International Space Station (ISS) is in an operational configuration. To fully utilize the ISS and take advantage of the modern protocols and updated Ku-band access, the Huntsville Operations Support Center (HOSC) has designed an approach to extend the Kuband forward link access for payload investigators to their on-orbit payloads. This dramatically increases the ground to ISS communications for those users. This access also enables the ISS flight controllers operating in the Payload Operations and Integration Center to have more direct control over the systems they are responsible for managing and operating. To extend the Ku-band forward link to the payload user community the development of a new command server is necessary. The HOSC subsystems were updated to process the Internet Protocol Encapsulated packets, enable users to use the service based on their approved services, and perform network address translation to insure that the packets are forwarded from the user to the correct payload repeating that process in reverse from ISS to the payload user. This paper presents the architecture, implementation, and lessons learned. This will include the integration of COTS hardware and software as well as how the device is incorporated into the operational mission of the ISS. Thus, this paper also discusses how this technology can be applicable to payload users of the ISS.

Module level solutions to solar cell polarization

DOEpatents

Xavier, Grace , Li; Bo, [San Jose, CA

2012-05-29

A solar cell module includes interconnected solar cells, a transparent cover over the front sides of the solar cells, and a backsheet on the backsides of the solar cells. The solar cell module includes an electrical insulator between the transparent cover and the front sides of the solar cells. An encapsulant protectively packages the solar cells. To prevent polarization, the insulator has resistance suitable to prevent charge from leaking from the front sides of the solar cells to other portions of the solar cell module by way of the transparent cover. The insulator may be attached (e.g., by coating) directly on an underside of the transparent cover or be a separate layer formed between layers of the encapsulant. The solar cells may be back junction solar cells.

Electrical evaluation of crack generation in SiNx and SiOxNy thin-film encapsulation layers for OLED displays

NASA Astrophysics Data System (ADS)

Park, Eun Kil; Kim, Sungmin; Heo, Jaeyeong; Kim, Hyeong Joon

2016-05-01

By measuring leakage current density, we detected crack generation in silicon nitride (SiNx) and silicon oxynitride (SiOxNy) thin-film encapsulation layers, and correlated with the films' water vapor permeability characteristics. After repeated bending cycles, both the changes in water vapor transmission rate and leakage current density were directly proportional to the crack density. Thick SiNx films had better water vapor barrier characteristics in their pristine state, but cyclic loading led to fast failure. Varying the atomic concentration of the SiOxNy films affected their bending reliability. We attribute these differences to changes in the shape of the crack tip as the oxygen content varies.

Effects of Composition of Alginate-Polyethylene Glycol Microcapsules and Transplant Site on Encapsulated Islet Graft Outcomes in Mice

PubMed Central

Villa, Chiara; Manzoli, Vita; Abreu, Maria M.; Verheyen, Connor A.; Seskin, Michael; Najjar, Mejdi; Molano, R. Damaris; Torrente, Yvan; Ricordi, Camillo; Tomei, Alice A.

2017-01-01

Background Understanding the effects of capsule composition and transplantation site on graft outcomes of encapsulated islets will aid in the development of more effective strategies for islet transplantation without immunosuppression. Methods Here, we evaluated the effects of transplanting alginate (ALG)-based microcapsules (Micro) in the confined and well-vascularized epididymal fat pad (EFP) site, a model of the human omentum, as opposed to free-floating in the intraperitoneal cavity (IP) in mice. We also examined the effects of reinforcing ALG with polyethylene glycol (PEG). To allow transplantation in the EFP site, we minimized capsule size to 500 ± 17 μm. Unlike ALG, PEG resists osmotic stress, hence we generated hybrid microcapsules by mixing PEG and ALG (MicroMix) or by coating ALG capsules with a 15 ± 2 μm PEG layer (Double). Results We found improved engraftment of fully allogeneic BALB/c islets in Micro capsules transplanted in the EFP (median reversal time [MRT], 1 day) versus the IP site (MRT, 5 days; P < 0.01) in diabetic C57BL/6 mice and of Micro encapsulated (MRT, 8 days) versus naked (MRT, 36 days; P < 0.01) baboon islets transplanted in the EFP site. Although in vitro viability and functionality of islets within MicroMix and Double capsules were comparable to Micro, addition of PEG to ALG in MicroMix capsules improved engraftment of allogeneic islets in the IP site, but resulted deleterious in the EFP site, probably due to lower biocompatibility. Conclusions Our results suggest that capsule composition and transplant site affect graft outcomes through their effects on nutrient availability, capsule stability, and biocompatibility. PMID:27525644

An Encapsulated Yersinia pseudotuberculosis Is a Highly Efficient Vaccine against Pneumonic Plague

PubMed Central

Derbise, Anne; Cerdà Marín, Alba; Ave, Patrick; Blisnick, Thierry; Huerre, Michel; Carniel, Elisabeth; Demeure, Christian E.

2012-01-01

Background Plague is still a public health problem in the world and is re-emerging, but no efficient vaccine is available. We previously reported that oral inoculation of a live attenuated Yersinia pseudotuberculosis, the recent ancestor of Yersinia pestis, provided protection against bubonic plague. However, the strain poorly protected against pneumonic plague, the most deadly and contagious form of the disease, and was not genetically defined. Methodology and Principal Findings The sequenced Y. pseudotuberculosis IP32953 has been irreversibly attenuated by deletion of genes encoding three essential virulence factors. An encapsulated Y. pseudotuberculosis was generated by cloning the Y. pestis F1-encoding caf operon and expressing it in the attenuated strain. The new V674pF1 strain produced the F1 capsule in vitro and in vivo. Oral inoculation of V674pF1 allowed the colonization of the gut without lesions to Peyer's patches and the spleen. Vaccination induced both humoral and cellular components of immunity, at the systemic (IgG and Th1 cells) and the mucosal levels (IgA and Th17 cells). A single oral dose conferred 100% protection against a lethal pneumonic plague challenge (33×LD50 of the fully virulent Y. pestis CO92 strain) and 94% against a high challenge dose (3,300×LD50). Both F1 and other Yersinia antigens were recognized and V674pF1 efficiently protected against a F1-negative Y. pestis. Conclusions and Significance The encapsulated Y. pseudotuberculosis V674pF1 is an efficient live oral vaccine against pneumonic plague, and could be developed for mass vaccination in tropical endemic areas to control pneumonic plague transmission and mortality. PMID:22348169

An encapsulated Yersinia pseudotuberculosis is a highly efficient vaccine against pneumonic plague.

PubMed

Derbise, Anne; Cerdà Marín, Alba; Ave, Patrick; Blisnick, Thierry; Huerre, Michel; Carniel, Elisabeth; Demeure, Christian E

2012-01-01

Plague is still a public health problem in the world and is re-emerging, but no efficient vaccine is available. We previously reported that oral inoculation of a live attenuated Yersinia pseudotuberculosis, the recent ancestor of Yersinia pestis, provided protection against bubonic plague. However, the strain poorly protected against pneumonic plague, the most deadly and contagious form of the disease, and was not genetically defined. The sequenced Y. pseudotuberculosis IP32953 has been irreversibly attenuated by deletion of genes encoding three essential virulence factors. An encapsulated Y. pseudotuberculosis was generated by cloning the Y. pestis F1-encoding caf operon and expressing it in the attenuated strain. The new V674pF1 strain produced the F1 capsule in vitro and in vivo. Oral inoculation of V674pF1 allowed the colonization of the gut without lesions to Peyer's patches and the spleen. Vaccination induced both humoral and cellular components of immunity, at the systemic (IgG and Th1 cells) and the mucosal levels (IgA and Th17 cells). A single oral dose conferred 100% protection against a lethal pneumonic plague challenge (33×LD(50) of the fully virulent Y. pestis CO92 strain) and 94% against a high challenge dose (3,300×LD(50)). Both F1 and other Yersinia antigens were recognized and V674pF1 efficiently protected against a F1-negative Y. pestis. The encapsulated Y. pseudotuberculosis V674pF1 is an efficient live oral vaccine against pneumonic plague, and could be developed for mass vaccination in tropical endemic areas to control pneumonic plague transmission and mortality.

Deformable microparticles with multiple functions for drug delivery and device testing

NASA Astrophysics Data System (ADS)

Thula, Taili T.

Since the HIV epidemic of the 1990s, researchers have attempted to develop a red blood cell analog. Even though some of these substitutes are now in Phase III of clinical trials, their use is limited by side effects and short half-life in the human body. As a result, there is still a need for an effective erythrocyte analog with minimum immunogenic and side effects, so that it can be used for multiple applications. Finding new approaches to develop more efficient blood substitutes will not only bring valuable advances in the clinical approach, but also in the area of in vitro testing of medical devices. We examined the feasibility of creating a deformable multi-functional, biodegradable, biocompatible particle for applications in drug delivery and device testing. As a preliminary evaluation, we synthesized different types of microcapsules using natural and synthetic polymers, various cross-linking agents, and diverse manufacturing techniques. After fully characterizing of each system, we determined the most promising red blood cell analog in terms of deformability, stability and toxicity. We also examined the encapsulation and release of bovine serum albumin (BSA) within these deformable particles. After removal of cross-linkers, zinc- and copper-alginate microparticles surrounded by multiple polyelectrolyte layers of chitosan oligosaccharide and alginate were deformable and remained stable under physiological pressures applied by the micropipette technique. In addition, multiple coatings decreased toxicity of heavy-metal crosslinked particles. BSA encapsulation and release from chitosan-alginate microspheres were contingent on the crosslinker and number of polyelectrolyte coatings, respectively. Further rheological studies are needed to determine how closely these particles simulate the behavior of erythrocytes. Also, studies on the encapsulation and release of different proteins, including hemoglobin, are needed to establish the desired controlled release of bioactive agents for the proposed delivery system.

Encapsulation and release of the hypnotic agent zolpidem from biodegradable polymer microparticles containing hydroxypropyl-beta-cyclodextrin.

PubMed

Trapani, Giuseppe; Lopedota, Angela; Boghetich, Giancarlo; Latrofa, Andrea; Franco, Massimo; Sanna, Enrico; Liso, Gaetano

2003-12-11

The goal of this study was to design a prolonged release system of the hypnotic agent zolpidem (ZP) useful for the treatment of insomnia. In this work, ZP alone or in the presence of HP-beta-CD was encapsulated in microparticles constituted by poly(DL-lactide) (PDLLA) and poly(DL-lactide-co-glycolide) (PLGA) and the drug release from these systems was evaluated. ZP alone-loaded microparticles were prepared by the classical O/W emulsion-solvent evaporation method. Conversely, ZP/HP-beta-CD containing microparticles were prepared by the W/O/W emulsion-solvent evaporation method following two different procedures (i.e. A and B). Following procedure A, the previously produced ZP/HP-beta-CD solid complex was added to the water phase of primary emulsion. In the procedure B, HP-beta-CD was added to the aqueous phase and ZP to the organic phase. The resulting microparticles were characterized about morphology, size, encapsulation efficiency and release rates. FT-IR, X-ray, and DSC results suggest the drug is in an essentially amorphous state within the microparticles. The release profiles of ZP from microparticles were in general biphasic, being characterized by an initial burst effect and a subsequent slow ZP release. It resulted that co-encapsulating ZP with or without HP-beta-CD in PDLLA and PLGA the drug release from the corresponding microparticles was protracted. Moreover, in a preliminary pharmacological screening, the ataxic activity in rats was investigated and it was found that intragastric administration of the ZP/HP-beta-CD/PLGA microparticles prepared according to procedure B produced the same ataxic induction time as the one induced by the currently used formulation Stilnox. Interestingly moreover, there was a longer ataxic lasting and a lower intensity of ataxia produced by the ZP/HP-beta-CD/PLGA-B-formulation already after 60 min following the administration. However, a need for further pharmacokinetic and pharmacodynamic studies resulted to fully evaluate the utility of this last formulation for the sustained delivery of ZP.

Simultant encapsulation of vitamin C and beta-carotene in sesame (Sesamum indicum l.) liposomes

NASA Astrophysics Data System (ADS)

Hudiyanti, D.; Fawrin, H.; Siahaan, P.

2018-04-01

In this study sesame liposomes were used to encapsulate both vitamin C and beta-carotene simultaneously. Liposomes were prepared with addition of cholesterol. The encapsulation efficiency (EE) of sesame liposomes for vitamin C in the present of beta-carotene was 77%. The addition of cholesterol increased the encapsulation efficiency. The highest encapsulation efficiency was 89% obtained in liposomes with 10% and 20% cholesterol. Contrary to that, the highest beta-carotene encapsulation efficiency of 78%, was found in the sesame liposomes prepared without the added cholesterol. Results showed that sesame liposomes can be used to encapsulate beta-carotene and vitamin C simultaneously. When beta-carotene and vitamin C were encapsulated concurrently, cholesterol intensified the efficiency of vitamin C encapsulation on the contrary it diminished the efficiency of beta-carotene encapsulation.

Tunable smart digital structure (SDS) to modularly assemble soft actuators with layered adhesive bonding

NASA Astrophysics Data System (ADS)

Jin, Hu; Dong, Erbao; Xu, Min; Xia, Qirong; Liu, Shuai; Li, Weihua; Yang, Jie

2018-01-01

Many shape memory alloy (SMA)-based soft actuators have specific composite structures and manufacture processes, and are therefore unique. However, these exclusive characteristics limit their capabilities and applications, so in this article a soft and smart digital structure (SDS) is proposed that acts like a modular unit to assemble soft actuators by a layered adhesive bonding process. The SDS is a fully soft structure that encapsulates a digital skeleton consisting of four groups of parallel and independently actuated SMA wires capable of outputting a four-channel tunable force. The layered adhesive bonding process modularly bonds several SDSs with an elastic backbone to fabricate a layered soft actuator where the elastic backbone is used to recover the SDSs in a cooling process using the SMA wires. Two kinds of SDS-based soft actuators were modularly assembled, an actuator, SDS-I, with a two-dimensional reciprocal motion, and an actuator, SDS-II, capable of bi-directional reciprocal motion. The thermodynamics and phase transformation modeling of the SDS-based actuator were analyzed. Several extensional soft actuators were also assembled by bonding the SDS with an anomalous elastic backbone or modularly assembling the SDS-Is and SDS-IIs. These modularly assembled soft actuators delivered more output channels and a complicated motion, e.g., an actinomorphic soft actuator with four SDS-Is jumps in a series of hierarchical heights and directional movement by tuning the input channels of the SDSs. This result showed that the SDS can modularly assemble multifarious soft actuators with diverse capabilities, steerability and tunable outputs.

Solar power satellite system definition study. Part 3: Preferred concept system definition

NASA Technical Reports Server (NTRS)

1978-01-01

A concise but complete system description for the preferred concept of the Solar Power Satellite System is presented. Significant selection decisions included the following: (1) single crystal silicon solar cells; (2) glass encapsulated solar cell blankets; (3) concentration ratio 1; (4) graphite composite materials for primary structure; (5) electric propulsion for attitude control; (6) klystron RF amplifier tubes for the transmitter; (7) one kilometer diameter transmitter with a design trans mission link output power of 5,000 megawatts; (8) construction in low earth orbit with self-powered transfer of satellite modules to geosynchronous orbit; and (9) two-stage winged fully reusable rocket vehicle for transportation to low earth orbit.

KSC-99pp0493

NASA Image and Video Library

1999-05-04

At Astrotech, Titusville, Fla., the fully encapsulated GOES-L weather satellite is ready for transfer to Launch Pad 36A, Cape Canaveral Air Station. The fourth of a new advanced series of geostationary weather satellites for the National Oceanic and Atmospheric Administration (NOAA), GOES-L is a three-axis inertially stabilized spacecraft that will provide pictures and perform atmospheric sounding at the same time. After it is launched, the satellite will undergo checkout and then provide backup capabilities for the existing, aging operational satellites. Once in orbit, the satellite will become GOES-11, joining GOES-8, GOES-9 and GOES-10 in space. The GOES is scheduled for launch aboard a Lockheed Martin Atlas II rocket later in May

Iterative design of peptide-based hydrogels and the effect of network electrostatics on primary chondrocyte behavior

PubMed Central

Sinthuvanich, Chomdao; Haines-Butterick, Lisa A.; Nagy, Katelyn J.; Schneider, Joel P.

2012-01-01

Iterative peptide design was used to generate two peptide-based hydrogels to study the effect of network electrostatics on primary chondrocyte behavior. MAX8 and HLT2 peptides have formal charge states of +7 and +5 per monomer, respectively. These peptides undergo triggered folding and self-assembly to afford hydrogel networks having similar rheological behavior and local network morphologies, yet different electrostatic character. Each gel can be used to directly encapsulate and syringe-deliver cells. The influence of network electrostatics on cell viability after encapsulation and delivery, extracellular matrix deposition, gene expression, and the bulk mechanical properties of the gel-cell constructs as a function of culture time was assessed. The less electropositive HLT2 gel provides a microenvironment more conducive to chondrocyte encapsulation, delivery, and phenotype maintenance. Cell viability was higher for this gel and although a moderate number of cells dedifferentiated to a fibroblast-like phenotype, many retained their chondrocytic behavior. As a result, gel-cell constructs prepared with HLT2, cultured under static in vitro conditions, contained more GAG and type II collagen resulting in mechanically superior constructs. Chondrocytes delivered in the more electropositive MAX8 gel experienced a greater degree of cell death during encapsulation and delivery and the remaining viable cells were less prone to maintain their phenotype. As a result, MAX8 gel-cell constructs had fewer cells, of which a limited number were capable of laying down cartilage-specific ECM. PMID:22841922

Iterative design of peptide-based hydrogels and the effect of network electrostatics on primary chondrocyte behavior.

PubMed

Sinthuvanich, Chomdao; Haines-Butterick, Lisa A; Nagy, Katelyn J; Schneider, Joel P

2012-10-01

Iterative peptide design was used to generate two peptide-based hydrogels to study the effect of network electrostatics on primary chondrocyte behavior. MAX8 and HLT2 peptides have formal charge states of +7 and +5 per monomer, respectively. These peptides undergo triggered folding and self-assembly to afford hydrogel networks having similar rheological behavior and local network morphologies, yet different electrostatic character. Each gel can be used to directly encapsulate and syringe-deliver cells. The influence of network electrostatics on cell viability after encapsulation and delivery, extracellular matrix deposition, gene expression, and the bulk mechanical properties of the gel-cell constructs as a function of culture time was assessed. The less electropositive HLT2 gel provides a microenvironment more conducive to chondrocyte encapsulation, delivery, and phenotype maintenance. Cell viability was higher for this gel and although a moderate number of cells dedifferentiated to a fibroblast-like phenotype, many retained their chondrocytic behavior. As a result, gel-cell constructs prepared with HLT2, cultured under static in vitro conditions, contained more GAG and type II collagen resulting in mechanically superior constructs. Chondrocytes delivered in the more electropositive MAX8 gel experienced a greater degree of cell death during encapsulation and delivery and the remaining viable cells were less prone to maintain their phenotype. As a result, MAX8 gel-cell constructs had fewer cells, of which a limited number were capable of laying down cartilage-specific ECM. Published by Elsevier Ltd.

Alginate Immobilization of Metabolic Enzymes (AIME) for High ...

EPA Pesticide Factsheets

Alginate Immobilization of Metabolic Enzymes (AIME) for High-Throughput Screening Assays DE DeGroot, RS Thomas, and SO SimmonsNational Center for Computational Toxicology, US EPA, Research Triangle Park, NC USAThe EPA’s ToxCast program utilizes a wide variety of high-throughput screening (HTS) assays to assess chemical perturbations of molecular and cellular endpoints. A key criticism of using HTS assays for toxicity assessment is the lack of xenobiotic metabolism (XM) which precludes both metabolic detoxification as well as bioactivation of chemicals tested in vitro thereby mischaracterizing the potential risk posed by these chemicals. To address this deficiency, we have developed an extracellular platform to retrofit existing HTS assays with XM activity. This platform utilizes the S9 fraction of liver homogenate encapsulated in an alginate gel network which reduces the cytotoxicity caused by direct addition of S9 to cells in culture. Alginate microspheres containing encapsulated human liver S9 were cross-linked to solid supports extending from a 96-well plate lid and were assayed using a pro-luciferin substrate specific for CYP3A4 (IPA). We demonstrate that S9 was successfully encapsulated and remained enzymatically active post-encapsulation with 5-10X the CYP3A4 activity as compared to 1 µg solubilized human liver S9. Ketoconazole, a known inhibitor of human CYP3A4, inhibited CYP3A4 activity in a concentration-dependent manner (IC50: 0.27 µM) and inhibiti

Anhydrous polymer-based coating with sustainable controlled release functionality for facile, efficacious impregnation, and delivery of antimicrobial peptides.

PubMed

Lim, Kaiyang; Saravanan, Rathi; Chong, Kelvin K L; Goh, Sharon H M; Chua, Ray R Y; Tambyah, Paul A; Chang, Matthew W; Kline, Kimberly A; Leong, Susanna S J

2018-04-17

Anhydrous polymers are actively explored as alternative materials to overcome limitations of conventional hydrogel-based antibacterial coating. However, the requirement for strong organic solvent in polymerization reactions often necessitates extra protection steps for encapsulation of target biomolecules, lowering encapsulation efficiency, and increasing process complexity. This study reports a novel coating strategy that allows direct solvation and encapsulation of antimicrobial peptides (HHC36) into anhydrous polycaprolactone (PCL) polymer-based dual layer coating. A thin 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) film is layered onto the peptide-impregnated PCL as a diffusion barrier, to modulate and enhance release kinetics. The impregnated peptides are eventually released in a controlled fashion. The use of 2,2,2-trifluoroethanol (TFE), as polymerization and solvation medium, induces the impregnated peptides to adopt highly stable turned conformation, conserving peptide integrity, and functionality during both encapsulation and subsequent release processes. The dual layer coating showed sustained antibacterial functionality, lasting for 14 days. In vivo assessment using an experimental mouse wounding model demonstrated good biocompatibility and significant antimicrobial efficacy of the coating under physiological conditions. The coating was translated onto silicone urinary catheters and showed promising antibacterial efficacy, even outperforming commercial silver-based Dover cather. This anhydrous polymer-based platform holds immense potential as an effective antibacterial coating to prevent clinical device-associated infections. The simplicity of the coating process enhances its industrial viability. © 2018 Wiley Periodicals, Inc.

The key role of exudative lesions and their encapsulation: lessons learned from the pathology of human pulmonary tuberculosis.

PubMed

Cardona, Pere-Joan

2015-01-01

A review of the pathology of human pulmonary TB cases at different stages of evolution in the pre-antibiotic era suggests that neutrophils play an instrumental role in the progression toward active TB. This progression is determined by the type of lesion generated. Thus, exudative lesions, in which neutrophils are the major cell type, are both triggered by and induce local high bacillary load, and tend to enlarge and progress toward liquefaction and cavitation. In contrast, proliferative lesions are triggered by low bacillary loads, mainly comprise epithelioid cells and fibroblasts and tend to fibrose, encapsulate and calcify, thus controlling the infection. Infection of the upper lobes is key to the progression toward active TB for two main reasons, namely poor breathing amplitude, which allows local bacillary accumulation, and the high mechanical stress to which the interlobular septae (which enclose secondary lobes) are submitted, which hampers their ability to encapsulate lesions. Overall, progressing factors can be defined as internal (exudative lesion, local bronchogenous dissemination, coalescence of lesions), with lympho-hematological dissemination playing a very limited role, or external (exogenous reinfection). Abrogating factors include control of the bacillary load and the local encapsulation process, as directed by interlobular septae. The age and extent of disease depend on the quality and speed with which lesions liquefy and disseminate bronchially, the volume of the slough, and the amount and distribution of the sloughing debris dispersed.

The key role of exudative lesions and their encapsulation: lessons learned from the pathology of human pulmonary tuberculosis

PubMed Central

Cardona, Pere-Joan

2015-01-01

A review of the pathology of human pulmonary TB cases at different stages of evolution in the pre-antibiotic era suggests that neutrophils play an instrumental role in the progression toward active TB. This progression is determined by the type of lesion generated. Thus, exudative lesions, in which neutrophils are the major cell type, are both triggered by and induce local high bacillary load, and tend to enlarge and progress toward liquefaction and cavitation. In contrast, proliferative lesions are triggered by low bacillary loads, mainly comprise epithelioid cells and fibroblasts and tend to fibrose, encapsulate and calcify, thus controlling the infection. Infection of the upper lobes is key to the progression toward active TB for two main reasons, namely poor breathing amplitude, which allows local bacillary accumulation, and the high mechanical stress to which the interlobular septae (which enclose secondary lobes) are submitted, which hampers their ability to encapsulate lesions. Overall, progressing factors can be defined as internal (exudative lesion, local bronchogenous dissemination, coalescence of lesions), with lympho-hematological dissemination playing a very limited role, or external (exogenous reinfection). Abrogating factors include control of the bacillary load and the local encapsulation process, as directed by interlobular septae. The age and extent of disease depend on the quality and speed with which lesions liquefy and disseminate bronchially, the volume of the slough, and the amount and distribution of the sloughing debris dispersed. PMID:26136741

Effects of encapsulated nitrate on growth performance, carcass characteristics, nitrate residues in tissues, and enteric methane emissions in beef steers: Finishing phase.

PubMed

Lee, C; Araujo, R C; Koenig, K M; Beauchemin, K A

2017-08-01

A finishing feedlot study was conducted with beef steers to determine effects of encapsulated nitrate (EN) on growth performance, carcass characteristics, methane production, and nitrate (NO) residues in tissues. The 132 crossbred steers were backgrounded in a feedlot for 91 d and transitioned for 28 days to the high-concentrate diets evaluated in the present study, maintaining the treatment and pen assignments designated at the start of the backgrounding period. The steers were initially assigned to 22 pens (6 animals per pen) in a randomized complete block design with BW (18 pens) and animals designated for methane measurement (4 pens) as blocking factors. Five animals in each pen designated for methane measurement (total of 20 animals) were monitored for methane emissions in respiratory chambers twice during the experiment. Pens received 3 dietary treatments (7 pens each): Control, a finishing diet supplemented with urea; 1.25% EN, control diet supplemented with 1.25% encapsulated NO in dietary DM that partially replaced urea; and 2.5% EN, control diet supplemented with 2.5% EN (DM basis) fully replacing urea. The final pen designated only for methane measurement received a fourth dietary treatment, 2.3% UEN, the control diet supplemented with unencapsulated NO (UEN) fully replacing urea. The cattle weighed 449 ± SD 32 kg at the start of the 150-d finishing period. The 2.5% EN diet decreased ( < 0.01) DMI compared with Control and 1.25% EN diets. Feeding EN tended to increase ( = 0.092) ADG compared with Control, and G:F was improved ( < 0.01) for EN compared with Control. No differences in methane production (g/d) and yield (g/kg DMI) were observed among treatments. Inclusion of EN in the diets increased ( ≤ 0.03) sorting in favor of large and medium particles and against small and fine particles. Plasma NO and NO concentrations were elevated ( < 0.01) with EN in a dose-response manner, but total blood methemoglobin levels for all treatments were low, below the detection limit. Feeding EN increased ( < 0.01) NO concentrations of samples from muscle, fat, liver, and kidney; NO concentrations of these tissues were similar between 1.25% EN and 2.3% UEN. In conclusion, inclusion of 2.5% EN in a finishing diet (DM basis; about 2% NO) did not cause NO toxicity or any health problems in the long term. In comparison with supplemental urea, feeding EN improved feed efficiency despite increases in sorting against dietary EN.

Culturally Adapted Psychotherapy and the Legitimacy of Myth: A Direct-Comparison Meta-Analysis

ERIC Educational Resources Information Center

Benish, Steven G.; Quintana, Stephen; Wampold, Bruce E.

2011-01-01

Psychotherapy is a culturally encapsulated healing practice that is created from and dedicated to specific cultural contexts (Frank & Frank, 1993; Wampold, 2007; Wrenn, 1962). Consequently, conventional psychotherapy is a practice most suitable for dominant cultural groups within North America and Western Europe but may be culturally incongruent…

Organic photosensitive devices

DOEpatents

Rand, Barry P; Forrest, Stephen R

2013-11-26

The present invention generally relates to organic photosensitive optoelectronic devices. More specifically, it is directed to organic photosensitive optoelectronic devices having a photoactive organic region containing encapsulated nanoparticles that exhibit plasmon resonances. An enhancement of the incident optical field is achieved via surface plasmon polariton resonances. This enhancement increases the absorption of incident light, leading to a more efficient device.

Binary particle separation in droplet microfluidics using acoustophoresis

NASA Astrophysics Data System (ADS)

Fornell, Anna; Cushing, Kevin; Nilsson, Johan; Tenje, Maria

2018-02-01

We show a method for separation of two particle species with different acoustic contrasts originally encapsulated in the same droplet in a continuous two-phase system. This was realized by using bulk acoustic standing waves in a 380 μm wide silicon-glass microfluidic channel. Polystyrene particles (positive acoustic contrast particles) and in-house synthesized polydimethylsiloxane (PDMS) particles (negative acoustic contrast particles) were encapsulated inside water-in-oil droplets either individually or in a mixture. At acoustic actuation of the system at the fundamental resonance frequency, the polystyrene particles were moved to the center of the droplet (pressure node), while the PDMS particles were moved to the sides of the droplet (pressure anti-nodes). The acoustic particle manipulation step was combined in series with a trifurcation droplet splitter, and as the original droplet passed through the splitter and was divided into three daughter droplets, the polystyrene particles were directed into the center daughter droplet, while the PDMS particles were directed into the two side daughter droplets. The presented method expands the droplet microfluidics tool-box and offers new possibilities to perform binary particle separation in droplet microfluidic systems.

Novel nanometer-level uniform amorphous carbon coating for boron powders by direct pyrolysis of coronene without solvent.

PubMed

Ye, ShuJun; Song, MingHui; Kumakura, Hiroaki

2015-01-30

A 3 nm coronene coating and a 4 nm amorphous carbon coating with a uniform shell-core encapsulation structure for nanosized boron (B) powders are formed by a simple process in which coronene is directly mixed with boron particles without a solvent and heated at 520 °C for 1 h or at 630 °C for 3 h in a vacuum-sealed silica tube. Coronene has a melting point lower than its decomposition temperature, which enables liquid coronene to cover B particles by liquid diffusion and penetration without the need for a solvent. The diffusion and penetration of coronene can extend to the boundaries of particles and to inside the agglomerated nanoparticles to form a complete shell-core encapsulated structure. As the temperature is increased, thermal decomposition of coronene on the B particles results in the formation of a uniform amorphous carbon coating layer. This novel and simple nanometer-level uniform amorphous carbon coating method can possibly be applied to many other powders; thus, it has potential applications in many fields at low cost.

Optical spectroscopy of excited exciton states in MoS2 monolayers in van der Waals heterostructures

NASA Astrophysics Data System (ADS)

Robert, C.; Semina, M. A.; Cadiz, F.; Manca, M.; Courtade, E.; Taniguchi, T.; Watanabe, K.; Cai, H.; Tongay, S.; Lassagne, B.; Renucci, P.; Amand, T.; Marie, X.; Glazov, M. M.; Urbaszek, B.

2018-01-01

The optical properties of MoS2 monolayers are dominated by excitons, but for spectrally broad optical transitions in monolayers exfoliated directly onto SiO2 substrates detailed information on excited exciton states is inaccessible. Encapsulation in hexagonal boron nitride (hBN) allows approaching the homogenous exciton linewidth, but interferences in the van der Waals heterostructures make direct comparison between transitions in optical spectra with different oscillator strength more challenging. Here we reveal in reflectivity and in photoluminescence excitation spectroscopy the presence of excited states of the A exciton in MoS2 monolayers encapsulated in hBN layers of calibrated thickness, allowing us to extrapolate an exciton binding energy of ≈220 meV. We theoretically reproduce the energy separations and oscillator strengths measured in reflectivity by combining the exciton resonances calculated for a screened two-dimensional Coulomb potential with transfer matrix calculations of the reflectivity for the van der Waals structure. Our analysis shows a very different evolution of the exciton oscillator strength with principal quantum number for the screened Coulomb potential as compared to the ideal two-dimensional hydrogen model.

Antifouling Thermoplastic Composites with Maleimide Encapsulated in Clay Nanotubes.

PubMed

Fu, Ye; Gong, Congcong; Wang, Wencai; Zhang, Liqun; Ivanov, Evgenii; Lvov, Yuri

2017-09-06

An antifouling ethylene-vinyl acetate copolymer (EVA) coating with halloysite clay nanotubes loaded with maleimide (TCPM) is prepared. Such antifoulant encapsulation allowed for extended release of TCPM and a long-lasting, efficient protection of the coated surface against marine microorganisms proliferation. Halloysite also induces the composite's anisotropy due to parallel alignment of the nanotubes. The maleimide loaded halloysite incorporated into the polymer matrix allowed for 12-month release of the bacterial inhibitor preventing fouling; it is much longer than the 2-3 month protection when TCPM is directly admixed into EVA. The antifouling properties of the EVA-halloysite nanocomposites were tested by monitoring surface adhesion and proliferation of marine V. natriegens bacteria with SEM. As compared to the composite directly doped with TCPM-antifoulant, there were much less bacteria accumulated on the EVA-halloysite-TCPM coating after a 2-month exposure to seawater. Field tests at South China Sea marine station further confirmed the formulation efficiency. The doping of 28 wt % TCPM loaded halloysite drastically enhanced material antifouling property, which promises wide applications for protective marine coating.

Designing injectable beta-hairpin peptide hydrogels for cartilage tissue engineering application

NASA Astrophysics Data System (ADS)

Sinthuvanich, Chomdao

In this work, it was demonstrated that peptide-based gels having different electrostatic network character but similar mechanical properties can be designed by modulating the primary sequence of the peptides used for self-assembly. As a result, HLT2 and HET1 peptides, having formal charge states of +5 per monomer, were designed using MAX8, a peptide with a charge state of +7 per monomer, as a template. Using gels prepared from all three peptides (MAX8, HLT2, and HET1), it was shown that the electropositive character of the network influences chondrocyte behavior. Specifically, the less electropositive gel (HLT2) is able to maintain chondrocyte viability and phenotype. In contrast, chondrocytes encapsulated in the more positively charged gel (MAX8) are more prone to dedifferentiation, resulting in tissue constructs with inferior mechanical properties. Gels prepared from peptides having the same net charge but differing only in their primary sequences (HLT2 and HET1) were also shown to influence cell behavior, but only during the early period of culturing. If constructs derived from these two different peptide gels are allowed to culture for extended times, their mechanical properties become similar. This suggests that the amino acid composition and sequence of the peptides used to make the gels also influences cell behavior, but perhaps not to the extent that network electrostatics plays. Supplementation of bioactive factors in the culturing media, as opposed to being encapsulated directly in the network, was shown to adversely affect the cellular response resulting in tissue constructs where extracellular matrix (ECM) components are non-uniformly distributed. When bioactive factors were encapsulated and co-delivered with cells, positive results were observed, particularly when cells were co-encapsulated with the growth factor, TGF-β1. The effect of TGF-β1 on cellular response and the mechanical properties of the tissue-engineered constructs is largely governed by the ability of the growth factor to be retained within the hydrogels and made available to the cells, which in turn, dictate the quality of the engineered tissue. Rational peptide design was also employed to generate negatively charged peptides capable of folding and self-assembling under physiological conditions to afford electronegative gel. Initial designs resulted in peptides that undergo gelation in response to a change in environmental pH and temperature. Modification of these initially designed peptides led to the design of VE3 and VEQ1, two negatively charged peptides that can be used to directly encapsulate chondrocytes providing gel-cell constructs with homogeneous cellular distribution. Finally, the positively charged peptide gel (HET1) and negatively charged peptide gel (VE3) were compared to investigate the influence of vastly different network electrostatics on the response of encapsulated primary chondrocytes. In these gels, a majority of cells were able to retain their chondrocyte phenotype within the scaffold regardless of which gel was used for encapsulation and delivery. However, the positively charge hydrogel is better at supporting cell proliferation and ECM accumulation. On the other hand, the cells encapsulated in the negatively charged hydrogel were less proliferative and the negatively charged hydrogel had a limited ability to retain ECM produced by the cells. In contrast, when culturing in the presence of TGF-β1, constructs derived from the negatively charged gel showed greater compressive moduli than those derived from the positively charged hydrogel. This difference is largely due to the amount of TGF-β1 made available to the encapsulated cells as a function of time, which was found to be governed by the electrostatic character of the hydrogel network. This work indicates that network electrostatics influence the response of encapsulated chondrocytes, retention of secreted ECM, and the diffusion of bioactive factors necessary for the generation of engineered cartilage. During the course of these studies, I have a serendipitous discovery that a derivative of one of the material forming β-hairpin peptides displays anticancer activity. Chapter 8 describes this peptide, SVS-1, and its mechanism of action. (Abstract shortened by UMI.).

Host-guest chemistry of dendrimer-drug complexes: 7. Formation of stable inclusions between acetylated dendrimers and drugs bearing multiple charges.

PubMed

Fang, Min; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen; Cheng, Yiyun

2012-03-15

Drug molecules bearing multiple charges usually form precipitates with cationic dendrimers, which presents a challenge during the preparation of dendrimer inclusions for these drugs. In the present study, fully acetylated polyamidoamine (PAMAM) dendrimers were proposed as stable vehicles for drug molecules bearing two negative charges such as Congo red and indocyanine green. NMR techniques including (1)H NMR and (1)H-(1)H NOESY were used to characterize the host-guest chemistry of acetylated dendrimer and these guest molecules. The cationic PAMAM dendrimer was found to form a precipitate with Congo red and indocyanine green, but the acetylated one avoided the formation of cross-linking structures in aqueous solutions. NOESY studies revealed the encapsulation of Congo red and indocyanine green within the interior cavities of PAMAM dendrimers at mild acidic conditions and acetylated dendrimers show much stronger ability to encapsulate the guest molecules than cationic ones. Also, UV-vis-NIR studies suggest that acetylated dendrimers significantly improve the photostability of indocyanine green and prevent the formation of indocyanine green J-aggregates in aqueous solutions. The present study provides a new insight into dendrimer-based host-guest systems, especially for those guest molecules bearing multiple charges. © 2012 American Chemical Society

Shrink Wrapping Cells in a Defined Extracellular Matrix to Modulate the Chemo-Mechanical Microenvironment.

PubMed

Palchesko, Rachelle N; Szymanski, John M; Sahu, Amrita; Feinberg, Adam W

2014-09-01

Cell-matrix interactions are important for the physical integration of cells into tissues and the function of insoluble, mechanosensitive signaling networks. Studying these interactions in vitro can be difficult because the extracellular matrix (ECM) proteins that adsorb to in vitro cell culture surfaces do not fully recapitulate the ECM-dense basement membranes to which cells such as cardiomyocytes and endothelial cells adhere to in vivo . Towards addressing this limitation, we have developed a surface-initiated assembly process to engineer ECM proteins into nanostructured, microscale sheets that can be shrink wrapped around single cells and small cell ensembles to provide a functional and instructive matrix niche. Unlike current cell encapsulation technology using alginate, fibrin or other hydrogels, our engineered ECM is similar in density and thickness to native basal lamina and can be tailored in structure and composition using the proteins fibronectin, laminin, fibrinogen, and/or collagen type IV. A range of cells including C2C12 myoblasts, bovine corneal endothelial cells and cardiomyocytes survive the shrink wrapping process with high viability. Further, we demonstrate that, compared to non-encapsulated controls, the engineered ECM modulates cytoskeletal structure, stability of cell-matrix adhesions and cell behavior in 2D and 3D microenvironments.

Shrink Wrapping Cells in a Defined Extracellular Matrix to Modulate the Chemo-Mechanical Microenvironment

PubMed Central

Palchesko, Rachelle N.; Szymanski, John M.; Sahu, Amrita; Feinberg, Adam W.

2014-01-01

Cell-matrix interactions are important for the physical integration of cells into tissues and the function of insoluble, mechanosensitive signaling networks. Studying these interactions in vitro can be difficult because the extracellular matrix (ECM) proteins that adsorb to in vitro cell culture surfaces do not fully recapitulate the ECM-dense basement membranes to which cells such as cardiomyocytes and endothelial cells adhere to in vivo. Towards addressing this limitation, we have developed a surface-initiated assembly process to engineer ECM proteins into nanostructured, microscale sheets that can be shrink wrapped around single cells and small cell ensembles to provide a functional and instructive matrix niche. Unlike current cell encapsulation technology using alginate, fibrin or other hydrogels, our engineered ECM is similar in density and thickness to native basal lamina and can be tailored in structure and composition using the proteins fibronectin, laminin, fibrinogen, and/or collagen type IV. A range of cells including C2C12 myoblasts, bovine corneal endothelial cells and cardiomyocytes survive the shrink wrapping process with high viability. Further, we demonstrate that, compared to non-encapsulated controls, the engineered ECM modulates cytoskeletal structure, stability of cell-matrix adhesions and cell behavior in 2D and 3D microenvironments. PMID:25530816

Numerical system for monitoring pressurized equipment

NASA Astrophysics Data System (ADS)

Dobra, Remus; Pasculescu, Dragos; Boca, Maria Loredana; Moldovan, Lucian

2016-12-01

Electrical devices for operation in potentially explosive atmospheres are designed and built in accordance with European standard EN 50015: 1995 ex. the pressurized enclosure "p". The type of protector p, by using a protective gas in the housing is intended to prevent the formation of an explosive atmosphere within it, while maintaining an overpressure to the surrounding atmosphere and, where appropriate, by the use dilution. Research conducted for pressurized encapsulation aimed at developing new procedures for determining the parameters of pressurization to allow safe use of electrical appliances. Pressurization with compensation for losses allegedly maintaining overpressure inside the enclosure when the outlets are closed, is made by feeding protective gas in an amount sufficient to fully compensate for losses from the housing inevitable pressurized and its associated pipework. The conditions and necessary measures that are required for appliances and equipment with potential ignition of explosive atmospheres are detailed in the SR EN 50016/2000. For pressurized encapsulation protection mode, the electric equipment can be maintained safety by the overpressure created inside them and in the supply pipes with air. The paper presents a modern method to determine the parameters of the electric equipment with pressurization enclosures. For controlling of such equipment, a specific algorithm has been developed and laboratory tested.

High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe

NASA Astrophysics Data System (ADS)

Bandurin, Denis A.; Tyurnina, Anastasia V.; Yu, Geliang L.; Mishchenko, Artem; Zólyomi, Viktor; Morozov, Sergey V.; Kumar, Roshan Krishna; Gorbachev, Roman V.; Kudrynskyi, Zakhar R.; Pezzini, Sergio; Kovalyuk, Zakhar D.; Zeitler, Uli; Novoselov, Konstantin S.; Patanè, Amalia; Eaves, Laurence; Grigorieva, Irina V.; Fal'Ko, Vladimir I.; Geim, Andre K.; Cao, Yang

2017-03-01

A decade of intense research on two-dimensional (2D) atomic crystals has revealed that their properties can differ greatly from those of the parent compound. These differences are governed by changes in the band structure due to quantum confinement and are most profound if the underlying lattice symmetry changes. Here we report a high-quality 2D electron gas in few-layer InSe encapsulated in hexagonal boron nitride under an inert atmosphere. Carrier mobilities are found to exceed 103 cm2 V-1 s-1 and 104 cm2 V-1 s-1 at room and liquid-helium temperatures, respectively, allowing the observation of the fully developed quantum Hall effect. The conduction electrons occupy a single 2D subband and have a small effective mass. Photoluminescence spectroscopy reveals that the bandgap increases by more than 0.5 eV with decreasing the thickness from bulk to bilayer InSe. The band-edge optical response vanishes in monolayer InSe, which is attributed to the monolayer's mirror-plane symmetry. Encapsulated 2D InSe expands the family of graphene-like semiconductors and, in terms of quality, is competitive with atomically thin dichalcogenides and black phosphorus.

Photovoltaic module with light reflecting backskin

DOEpatents

Gonsiorawski, Ronald C [Danvers, MA

2007-07-03

A photovoltaic module comprises electrically interconnected and mutually spaced photovoltaic cells that are encapsulated by a light-transmitting encapsulant between a light-transparent front cover and a back cover, with the back cover sheet being an ionomer/nylon alloy embossed with V-shaped grooves running in at least two directions and coated with a light reflecting medium so as to provide light-reflecting facets that are aligned with the spaces between adjacent cells and oriented so as to reflect light falling in those spaces back toward said transparent front cover for further internal reflection onto the solar cells, whereby substantially all of the reflected light will be internally reflected from said cover sheet back to the photovoltaic cells, thereby increasing the current output of the module. The internal reflector improves power output by as much as 67%.

Recent Developments of Liposomes as Nanocarriers for Theranostic Applications

PubMed Central

Xing, Hang; Hwang, Kevin; Lu, Yi

2016-01-01

Liposomes are nanocarriers comprised of lipid bilayers encapsulating an aqueous core. The ability of liposomes to encapsulate a wide variety of diagnostic and therapeutic agents has led to significant interest in utilizing liposomes as nanocarriers for theranostic applications. In this review, we highlight recent progress in developing liposomes as nanocarriers for a) diagnostic applications to detect proteins, DNA, and small molecule targets using fluorescence, magnetic resonance, ultrasound, and nuclear imaging; b) therapeutic applications based on small molecule-based therapy, gene therapy and immunotherapy; and c) theranostic applications for simultaneous detection and treatment of heavy metal toxicity and cancers. In addition, we summarize recent studies towards understanding of interactions between liposomes and biological components. Finally, perspectives on future directions in advancing the field for clinical translations are also discussed. PMID:27375783

Temperature and refractive index measurements using long-period fiber gratings fabricated by femtosecond laser

NASA Astrophysics Data System (ADS)

Yu, Yongqin; Zheng, Jiarong; Yi, Kai; Ruan, Shuangchen; Du, Chenlin; Huang, Jianhui; Zhong, Wansheng

2011-12-01

Long period fiber gratings (LPFGs) with different periods in the standard single mode fiber were fabricated, using laser direct writing method, by femtosecond laser pulses with pulse width of 200 fs and the repetition rate of 250 kHz at a center wavelength of 800 nm in air. Comparative with bare LPFG in temperature sensor, LPFG had been encapsulated using large coefficient of thermal expansion of epoxy polymer and Aluminum to enhance the temperature sensitivity. The results showed that the temperature sensitivity of encapsulated LPFG was 2 times than that of bare LPFG. In addition, we also researched the relationship between resonant wavelength and surrounding refractive index (SRI) when LPFG immersed in refractive index of solution of different index at 20 degree Celsius.

Source holder collimator for encapsulating radioactive material and collimating the emanations from the material

DOEpatents

Laurer, G.R.

1974-01-22

This invention provides a transportable device capable of detecting normal levels of a trace element, such as lead in a doughnutshaped blood sample by x-ray fluorescence with a minimum of sample preparation in a relatively short analyzing time. In one embodiment, the blood is molded into a doughnut-shaped sample around an annular array of low-energy radioactive material that is at the center of the doughnut-shaped sample but encapsulated in a collimator, the latter shielding a detector that is close to the sample and facing the same so that the detector receives secondary emissions from the sample while the collimator collimates ths primary emissions from the radioactive material to direct these emissions toward the sample around 360 deg and away from the detector. (Official Gazette)

PIONEER VENUS 2 MULTI PROBE IS ENCAPSULATED IN PROTECTIVE SHROUD

NASA Technical Reports Server (NTRS)

1978-01-01

Encapsulation of the Pioneer Venus Multiprobe in its protective nose fairing is closely monitored by technicians in Hangar AO. The 2,000-pound spacecraft is one of two being launched toward the planet Venus. The Multiprobe is scheduled for launch aboard an Atlas Centaur rocket on August 7. Flying a direct path to the cloud-shrouded planet, the Multiprobe will reach Venus five days after the arrival of its sister spacecraft, the Pioneer Venus Orbiter, which was launched May 20, 1978. Three weeks before the Multiprobe reaches Venus, its four heavily instrumented scientific probes (seen on top of the spacecraft's main body or ''bus'') will be released and will impact at various points on the planet's surface. Together, the two spacecraft will conduct a thorough scientific exploration of the planet Venus.

Hybrid chip-on-board LED module with patterned encapsulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soer, Wouter Anthon; Helbing, Rene; Huang, Guan

Different wavelength conversion materials, or different concentrations of a wavelength conversion material are used to encapsulate the light emitting elements of different colors of a hybrid light emitting module. In an embodiment of this invention, second light emitting elements (170) of a particular color are encapsulated with a transparent second encapsulant (120;420;520), while first light emitting elements (160) of a different color are encapsulated with a wavelength conversion first encapsulant (110;410;510). In another embodiment of this invention, a particular second set of second and third light emitting elements (170,580) of different colors is encapsulated with a different encapsulant than anothermore » first set of first light emitting elements (160).« less

Practicality of performing medical procedures in chemical protective ensembles.

PubMed

Garner, Alan; Laurence, Helen; Lee, Anna

2004-04-01

To determine whether certain life saving medical procedures can be successfully performed while wearing different levels of personal protective equipment (PPE), and whether these procedures can be performed in a clinically useful time frame. We assessed the capability of eight medical personnel to perform airway maintenance and antidote administration procedures on manikins, in all four described levels of PPE. The levels are: Level A--a fully encapsulated chemically resistant suit; Level B--a chemically resistant suit, gloves and boots with a full-faced positive pressure supplied air respirator; Level C--a chemically resistant splash suit, boots and gloves with an air-purifying positive or negative pressure respirator; Level D--a work uniform. Time in seconds to inflate the lungs of the manikin with bag-valve-mask, laryngeal mask airway (LMA) and endotracheal tube (ETT) were determined, as was the time to secure LMAs and ETTs with either tape or linen ties. Time to insert a cannula in a manikin was also determined. There was a significant difference in time taken to perform procedures in differing levels of personal protective equipment (F21,72 = 1.75, P = 0.04). Significant differences were found in: time to lung inflation using an endotracheal tube (A vs. C mean difference and standard error 75.6 +/- 23.9 s, P = 0.03; A vs. D mean difference and standard error 78.6 +/- 23.9 s, P = 0.03); time to insert a cannula (A vs. D mean difference and standard error 63.6 +/- 11.1 s, P < 0.001; C vs. D mean difference and standard error 40.0 +/- 11.1 s, P = 0.01). A significantly greater time to complete procedures was documented in Level A PPE (fully encapsulated suits) compared with Levels C and D. There was however, no significant difference in times between Level B and Level C. The common practice of equipping hospital and medical staff with only Level C protection should be re-evaluated.

Incorporation of T4 bacteriophage in electrospun fibres.

PubMed

Korehei, R; Kadla, J

2013-05-01

Antibacterial food packaging materials, such as bacteriophage-activated electrospun fibrous mats, may address concerns triggered by waves of bacterial food contamination. To address this, we investigated several efficient methods for incorporating T4 bacteriophage into electrospun fibrous mats. The incorporation of T4 bacteriophage using simple suspension electrospinning led to more than five orders of magnitude decrease in bacteriophage activity. To better maintain bacteriophage viability, emulsion electrospinning was developed where the T4 bacteriophage was pre-encapsulated in an alginate reservoir via an emulsification process and subsequently electrospun into fibres. This resulted in an increase in bacteriophage viability, but there was still two orders of magnitude drop in activity. Using a coaxial electrospinning process, full bacteriophage activity could be maintained. In this process, a core/shell fibre structure was formed with the T4 bacteriophage being directly incorporated into the fibre core. The core/shell fibre encapsulated bacteriophage exhibited full bacteriophage viability after storing for several weeks at +4°C. Coaxial electrospinning was shown to be capable of encapsulating bacteriophages with high loading capacity, high viability and long storage time. These results are significant in the context of controlling and preventing bacterial infections in perishable foods during storage. © 2013 The Society for Applied Microbiology.

Vertical Graphene Growth on SiO Microparticles for Stable Lithium Ion Battery Anodes.

PubMed

Shi, Liurong; Pang, Chunlei; Chen, Shulin; Wang, Mingzhan; Wang, Kexin; Tan, Zhenjun; Gao, Peng; Ren, Jianguo; Huang, Youyuan; Peng, Hailin; Liu, Zhongfan

2017-06-14

Silicon-based materials are considered as strong candidates to next-generation lithium ion battery anodes because of their ultrahigh specific capacities. However, the pulverization and delamination of electrochemical active materials originated from the huge volume expansion (>300%) of silicon during the lithiation process results in rapid capacity fade, especially in high mass loading electrodes. Here we demonstrate that direct chemical vapor deposition (CVD) growth of vertical graphene nanosheets on commercial SiO microparticles can provide a stable conducting network via interconnected vertical graphene encapsulation during lithiation, thus remarkably improving the cycling stability in high mass loading SiO anodes. The vertical graphene encapsulated SiO (d-SiO@vG) anode exhibits a high capacity of 1600 mA h/g and a retention up to 93% after 100 cycles at a high areal mass loading of 1.5 mg/cm 2 . Furthermore, 5 wt % d-SiO@vG as additives increased the energy density of traditional graphite/NCA 18650 cell by ∼15%. We believe that the results strongly imply the important role of CVD-grown vertical graphene encapsulation in promoting the commercial application of silicon-based anodes.

RBC micromotors carrying multiple cargos towards potential theranostic applications.

PubMed

Wu, Zhiguang; Esteban-Fernández de Ávila, Berta; Martín, Aída; Christianson, Caleb; Gao, Weiwei; Thamphiwatana, Soracha Kun; Escarpa, Alberto; He, Qiang; Zhang, Liangfang; Wang, Joseph

2015-08-28

Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic resonance imaging. The simultaneous encapsulation of the imaging nanoparticles and therapeutic payloads within the same RBC micromotor has a minimal effect upon its propulsion behavior. The ability of the RBC micromotors to transport imaging and therapeutic agents at high speed and spatial precision through a complex microchannel network is also demonstrated. Such ability to load and transport diagnostic imaging agents and therapeutic drugs within a single cell-based motor, in addition to a lower toxicity observed once the drug is encapsulated within the multicargo RBC motor, opens the door to the development of theranostic micromotors that may simultaneously treat and monitor diseases.

"Lollipop-shaped" high-sensitivity Microelectromechanical Systems vector hydrophone based on Parylene encapsulation

NASA Astrophysics Data System (ADS)

Liu, Yuan; Wang, Renxin; Zhang, Guojun; Du, Jin; Zhao, Long; Xue, Chenyang; Zhang, Wendong; Liu, Jun

2015-07-01

This paper presents methods of promoting the sensitivity of Microelectromechanical Systems (MEMS) vector hydrophone by increasing the sensing area of cilium and perfect insulative Parylene membrane. First, a low-density sphere is integrated with the cilium to compose a "lollipop shape," which can considerably increase the sensing area. A mathematic model on the sensitivity of the "lollipop-shaped" MEMS vector hydrophone is presented, and the influences of different structural parameters on the sensitivity are analyzed via simulation. Second, the MEMS vector hydrophone is encapsulated through the conformal deposition of insulative Parylene membrane, which enables underwater acoustic monitoring without any typed sound-transparent encapsulation. Finally, the characterization results demonstrate that the sensitivity reaches up to -183 dB (500 Hz 0dB at 1 V/ μPa ), which is increased by more than 10 dB, comparing with the previous cilium-shaped MEMS vector hydrophone. Besides, the frequency response takes on a sensitivity increment of 6 dB per octave. The working frequency band is 20-500 Hz and the concave point depth of 8-shaped directivity is beyond 30 dB, indicating that the hydrophone is promising in underwater acoustic application.

Prostate-Specific Membrane Antigen Targeted Polymersomes for Delivering Mocetinostat and Docetaxel to Prostate Cancer Cell Spheroids.

PubMed

Karandish, Fataneh; Haldar, Manas K; You, Seungyong; Brooks, Amanda E; Brooks, Benjamin D; Guo, Bin; Choi, Yongki; Mallik, Sanku

2016-11-30

Prostate cancer cells overexpress the prostate-specific membrane antigen (PSMA) receptors on the surface. Targeting the PSMA receptor creates a unique opportunity for drug delivery. Docetaxel is a Food and Drug Administration-approved drug for treating metastatic and androgen-independent prostate cancer, and mocetinostat is a potent inhibitor of class I histone deacetylases. In this study, we prepared reduction-sensitive polymersomes presenting folic acid on the surface and encapsulating either docetaxel or mocetinostat. The presence of folic acid allowed efficient targeting of the PSMA receptor and subsequent internalization of the polymeric vesicles in cultured LNCaP prostate cancer cell spheroids. The intracellular reducing agents efficiently released docetaxel and mocetinostat from the polymersomes. The combination of the two drug-encapsulated polymersome formulations significantly ( p < 0.05) decreased the viability of the LNCaP cells (compared to free drugs or control) in three-dimensional spheroid cultures. The calculated combination index value indicated a synergistic effect for the combination of mocetinostat and docetaxel. Thus, our PSMA-targeted drug-encapsulated polymersomes has the potential to lead to a new direction in prostate cancer therapy that decreases the toxicity and increases the efficacy of the drug delivery systems.

Prostate-Specific Membrane Antigen Targeted Polymersomes for Delivering Mocetinostat and Docetaxel to Prostate Cancer Cell Spheroids

PubMed Central

2016-01-01

Prostate cancer cells overexpress the prostate-specific membrane antigen (PSMA) receptors on the surface. Targeting the PSMA receptor creates a unique opportunity for drug delivery. Docetaxel is a Food and Drug Administration-approved drug for treating metastatic and androgen-independent prostate cancer, and mocetinostat is a potent inhibitor of class I histone deacetylases. In this study, we prepared reduction-sensitive polymersomes presenting folic acid on the surface and encapsulating either docetaxel or mocetinostat. The presence of folic acid allowed efficient targeting of the PSMA receptor and subsequent internalization of the polymeric vesicles in cultured LNCaP prostate cancer cell spheroids. The intracellular reducing agents efficiently released docetaxel and mocetinostat from the polymersomes. The combination of the two drug-encapsulated polymersome formulations significantly (p < 0.05) decreased the viability of the LNCaP cells (compared to free drugs or control) in three-dimensional spheroid cultures. The calculated combination index value indicated a synergistic effect for the combination of mocetinostat and docetaxel. Thus, our PSMA-targeted drug-encapsulated polymersomes has the potential to lead to a new direction in prostate cancer therapy that decreases the toxicity and increases the efficacy of the drug delivery systems. PMID:27917408

Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

NASA Astrophysics Data System (ADS)

Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki; Young Jeong, Hu; Galeano, Carolina; Schüth, Ferdi; Terasaki, Osamu

2014-11-01

Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Direct intratumoral infusion of liposome encapsulated rhenium radionuclides for cancer therapy: Effects of nonuniform intratumoral dose distribution

PubMed Central

Hrycushko, Brian A.; Li, Shihong; Goins, Beth; Otto, Randal A.; Bao, Ande

2011-01-01

Purpose: Focused radiation therapy by direct intratumoral infusion of lipid nanoparticle (liposome)-carried beta-emitting radionuclides has shown promising results in animal model studies; however, little is known about the impact the intratumoral liposomal radionuclide distribution may have on tumor control. The primary objective of this work was to investigate the effects the intratumoral absorbed dose distributions from this cancer therapy modality have on tumor control and treatment planning by combining dosimetric and radiobiological modeling with in vivo imaging data. Methods:99mTc-encapsulated liposomes were intratumorally infused with a single injection location to human head and neck squamous cell carcinoma xenografts in nude rats. High resolution in vivo planar imaging was performed at various time points for quantifying intratumoral retention following infusion. The intratumoral liposomal radioactivity distribution was obtained from 1 mm resolution pinhole collimator SPECT imaging coregistered with CT imaging of excised tumors at 20 h postinfusion. Coregistered images were used for intratumoral dosimetric and radiobiological modeling at a voxel level following extrapolation to the therapeutic analogs, 186Re∕188Re liposomes. Effective uniform dose (EUD) and tumor control probability (TCP) were used to assess therapy effectiveness and possible methods of improving upon tumor control with this radiation therapy modality. Results: Dosimetric analysis showed that average tumor absorbed doses of 8.6 Gy∕MBq (318.2 Gy∕mCi) and 5.7 Gy∕MBq (209.1 Gy∕mCi) could be delivered with this protocol of radiation delivery for 186Re∕188Re liposomes, respectively, and 37–92 MBq (1–2.5 mCi)∕g tumor administered activity; however, large intratumoral absorbed dose heterogeneity, as seen in dose-volume histograms, resulted in insignificant values of EUD and TCP for achieving tumor control. It is indicated that the use of liposomes encapsulating radionuclides with higher energy beta emissions, dose escalation through increased specific activity, and increasing the number of direct tumor infusion sites improve tumor control. For larger tumors, the use of multiple infusion locations was modeled to be much more efficient, in terms of activity usage, at improving EUD and TCP to achieve a tumoricidal effect. Conclusions: Direct intratumoral infusion of beta-emitting radionuclide encapsulated liposomes shows promise for cancer therapy by achieving large focally delivered tumor doses. However, the results of this work also indicate that average tumor dose may underestimate tumoricidal effect due to substantial heterogeneity in intratumoral liposomal radionuclide distributions. The resulting intratumoral distribution of liposomes following infusion should be taken into account in treatment planning and evaluation in a clinical setting for an optimal cancer therapy. PMID:21520844

Direct intratumoral infusion of liposome encapsulated rhenium radionuclides for cancer therapy: Effects of nonuniform intratumoral dose distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrycushko, Brian A.; Li Shihong; Goins, Beth

2011-03-15

Purpose: Focused radiation therapy by direct intratumoral infusion of lipid nanoparticle (liposome)-carried beta-emitting radionuclides has shown promising results in animal model studies; however, little is known about the impact the intratumoral liposomal radionuclide distribution may have on tumor control. The primary objective of this work was to investigate the effects the intratumoral absorbed dose distributions from this cancer therapy modality have on tumor control and treatment planning by combining dosimetric and radiobiological modeling with in vivo imaging data. Methods: {sup 99m}Tc-encapsulated liposomes were intratumorally infused with a single injection location to human head and neck squamous cell carcinoma xenografts inmore » nude rats. High resolution in vivo planar imaging was performed at various time points for quantifying intratumoral retention following infusion. The intratumoral liposomal radioactivity distribution was obtained from 1 mm resolution pinhole collimator SPECT imaging coregistered with CT imaging of excised tumors at 20 h postinfusion. Coregistered images were used for intratumoral dosimetric and radiobiological modeling at a voxel level following extrapolation to the therapeutic analogs, {sup 186}Re/{sup 188}Re liposomes. Effective uniform dose (EUD) and tumor control probability (TCP) were used to assess therapy effectiveness and possible methods of improving upon tumor control with this radiation therapy modality. Results: Dosimetric analysis showed that average tumor absorbed doses of 8.6 Gy/MBq (318.2 Gy/mCi) and 5.7 Gy/MBq (209.1 Gy/mCi) could be delivered with this protocol of radiation delivery for {sup 186}Re/{sup 188}Re liposomes, respectively, and 37-92 MBq (1-2.5 mCi)/g tumor administered activity; however, large intratumoral absorbed dose heterogeneity, as seen in dose-volume histograms, resulted in insignificant values of EUD and TCP for achieving tumor control. It is indicated that the use of liposomes encapsulating radionuclides with higher energy beta emissions, dose escalation through increased specific activity, and increasing the number of direct tumor infusion sites improve tumor control. For larger tumors, the use of multiple infusion locations was modeled to be much more efficient, in terms of activity usage, at improving EUD and TCP to achieve a tumoricidal effect. Conclusions: Direct intratumoral infusion of beta-emitting radionuclide encapsulated liposomes shows promise for cancer therapy by achieving large focally delivered tumor doses. However, the results of this work also indicate that average tumor dose may underestimate tumoricidal effect due to substantial heterogeneity in intratumoral liposomal radionuclide distributions. The resulting intratumoral distribution of liposomes following infusion should be taken into account in treatment planning and evaluation in a clinical setting for an optimal cancer therapy.« less

Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination

PubMed Central

Derbise, Anne; Hanada, Yuri; Khalifé, Manal; Carniel, Elisabeth; Demeure, Christian E.

2015-01-01

Background No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably. Methodology/Principal Findings The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1—Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis. Significance VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration. PMID:26473734

Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination.

PubMed

Derbise, Anne; Hanada, Yuri; Khalifé, Manal; Carniel, Elisabeth; Demeure, Christian E

2015-01-01

No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably. The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis. VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

Hybrid Lipid/Polymer Nanoparticles for Pulmonary Delivery of siRNA: Development and Fate Upon In Vitro Deposition on the Human Epithelial Airway Barrier.

PubMed

d'Angelo, Ivana; Costabile, Gabriella; Durantie, Estelle; Brocca, Paola; Rondelli, Valeria; Russo, Annapina; Russo, Giulia; Miro, Agnese; Quaglia, Fabiana; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Ungaro, Francesca

2017-10-16

Nowadays, the downregulation of genes involved in the pathogenesis of severe lung diseases through local siRNA delivery appears an interesting therapeutic approach. In this study, we propose novel hybrid lipid-polymer nanoparticles (hNPs) consisting of poly(lactic-co-glycolic) acid (PLGA) and dipalmitoyl phosphatidylcholine (DPPC) as siRNA inhalation system. A panel of DPPC/PLGA hNPs was prepared by emulsion/solvent diffusion and fully characterized. A combination of model siRNAs against the sodium transepithelial channel (ENaC) was entrapped in optimized hNPs comprising or not poly(ethylenimine) (PEI) as third component. siRNA-loaded hNPs were characterized for encapsulation efficiency, release kinetics, aerodynamic properties, and stability in artificial mucus (AM). The fate and cytotoxicity of hNPs upon aerosolization on a triple cell co-culture model (TCCC) mimicking human epithelial airway barrier were assessed. Finally, the effect of siRNA-loaded hNPs on ENaC protein expression at 72 hours was evaluated in A549 cells. Optimized muco-inert hNPs encapsulating model siRNA with high efficiency were produced. The developed hNPs displayed a hydrodynamic diameter of ∼150 nm, a low polydispersity index, a negative ζ potential close to -25 mV, and a peculiar triphasic siRNA release lasting for 5 days, which slowed down in the presence of PEI. siRNA formulations showed optimal in vitro aerosol performance after delivery with a vibrating mesh nebulizer. Furthermore, small-angle X-ray scattering analyses highlighted an excellent stability upon incubation with AM, confirming the potential of hNPs for direct aerosolization on mucus-lined airways. Studies in TCCC confirmed that fluorescent hNPs are internalized inside airway epithelial cells and do not exert any cytotoxic or acute proinflammatory effect. Finally, a prolonged inhibition of ENaC protein expression was observed in A549 cells upon treatment with siRNA-loaded hNPs. Results demonstrate the great potential of hNPs as carriers for pulmonary delivery of siRNA, prompting toward investigation of their therapeutic effectiveness in severe lung diseases.

Characterisation of the Xenogeneic Immune Response to Microencapsulated Fetal Pig Islet-Like Cell Clusters Transplanted into Immunocompetent C57BL/6 Mice

PubMed Central

Ratnapala, Sabina; Foster, Jayne; Vaghjiani, Vijesh; Manuelpillai, Ursula; Tuch, Bernard E.

2013-01-01

Xenotransplantation of microencapsulated fetal pig islet-like cell clusters (FP ICCs) offers a potential cellular therapy for type 1 diabetes. Although microcapsules prevent direct contact of the host immune system with the xenografted tissue, poor graft survival is still an issue. This study aimed to characterise the nature of the host immune cells present on the engrafted microcapsules and effects on encapsulated FP ICCs that were transplanted into immunocompetent mice. Encapsulated FP ICCs were transplanted into the peritoneal cavity of C57BL/6 mice. Grafts retrieved at days 1, 3, 7, 14 and 21 post-transplantation were analysed for pericapsular fibrotic overgrowth (PFO), cell viability, intragraft porcine gene expression, macrophages, myofibroblasts and intraperitoneal murine cytokines. Graft function was assessed ex vivo by insulin secretion studies. Xenogeneic immune response to encapsulated FP ICCs was associated with enhanced intragraft mRNA expression of porcine antigens MIP-1α, IL-8, HMGB1 and HSP90 seen within the first two weeks post-transplantation. This was associated with the recruitment of host macrophages, infiltration of myofibroblasts and collagen deposition leading to PFO which was evident from day 7 post-transplantation. This was accompanied by a decrease in cell viability and loss of FP ICC architecture. The only pro-inflammatory cytokine detected in the murine peritoneal flushing was TNF-α with levels peaking at day 7 post transplantation. This correlated with the onset of PFO at day 7 implying activated macrophages as its source. The anti-inflammatory cytokines detected were IL-5 and IL-4 with levels peaking at days 1 and 7, respectively. Porcine C-peptide was undetectable at all time points post-transplantation. PFO was absent and murine intraperitoneal cytokines were undetectable when empty microcapsules were transplanted. In conclusion, this study demonstrated that the macrophages are direct effectors of the xenogeneic immune response to encapsulated FP ICCs leading to PFO mediated by a combination of both pro- and anti-inflammatory cytokines. PMID:23554983

Controlling drug efficiency by encapsulation into carbon nanotubes: A theoretical study of the antitumor Cisplatin and the anti-HIV TIBO molecules

NASA Astrophysics Data System (ADS)

Bessrour, R.; Belmiloud, Y.; Hosni, Z.; Tangour, B.

2012-06-01

From the beginning of last century, Paul Ehrlich, a specialist in the immune system and the Nobel Prize (1908) had raised the possibility of "magic bullets" can directly address, in an organism, drugs in a particular area of the body, sparing all other parts of side effects. Carbon nanotubes (CNTs) have particular property to cross cell membranes easily. In an effort to optimize the use of CNT as drug nanocarriers, we divided our study into two parts. In the first, our concern was to find the minimum diameter of a single wall CNT can encapsulate an anticancer drug that iscisplatin without altering its geometry in order conserve its therapeutic power. Behavior of one and two Cisplatin(Cp) molecules confined in capped and opened single-walled carbon nanotubes (CNTs) is studied by means of ab-initio calculations. Single molecule binding energies clearly exhibit encapsulation dependence on tube diameters that range from 6.26 Å to 12.04 Å. A weak stabilization energy of the Cp@(11,0) equal to -70 kcal.mol-1 has been obtained corresponding to a CNT's diameter of 8.5Å. We noticed that Cisplatin molecule changes shape when encapsulated into CNTs' whose diameters are less than 7.6 Å. In the presence of a second Cisplatin molecule in the (10,0) CNT, preferred position stays parallel to CNT's axis leading to a linear density of roughly 1588 molecules/μm of CNT's length corresponding to a linear density of 7.9 10-19 g/μm. The 195Pt chemical shift tensors are calculated using GIAO method. NMR calculations reveal that Platinum chemical shift is sensitive to CNT's diameter and is linearly correlated to confinement energy. 195Pt chemical shift measurement may be a direct method to access to the diameter of the encapsulating CNT's and to control the amount of drug molecule transported by this CNT. In the second part, the opposite has been sought is to say how the use of nanotubes with different diameters can control the change in a geometry of an anti-HIV drug that is TIBO molecule to bypass the mutation of the virus which wiped out its therapeutic effect. This work deals with the butterfly conformation control of the anti-HIV TIBO molecule confined into carbon nanotubes (CNT). This theoretical study concerns the variation of some pertinent conformation descriptors such as butterfly angle, wingspan, volume, dipole moment, solvation energy and confinement energy versus carbon nanotube diameters. Obtained results show that it is possible to describe the configurations of actual drugs as 8-Cl or 9-Cl TIBO as the parent molecule TIBO encapsulated in an adequate CNT. Our approach indicates that drug confinement inside CNTs may be a promising way to use a same drug in order to fellow HIV virus mutations.

Computational Analysis of a Zn-Bound Tris(imidazolyl) Calix[6]arene Aqua Complex: Toward Incorporating Second-Coordination Sphere Effects into Carbonic Anhydrase Biomimetics.

PubMed

Koziol, Lucas; Essiz, Sebnem G; Wong, Sergio E; Lau, Edmond Y; Valdez, Carlos A; Satcher, Joe H; Aines, Roger D; Lightstone, Felice C

2013-03-12

Molecular dynamics simulations and quantum-mechanical calculations were performed to characterize a supramolecular tris(imidazolyl) calix[6]arene Zn(2+) aqua complex, as a biomimetic model for the catalyzed hydration of carbon dioxide to bicarbonate, H2O + CO2 → H(+) + HCO3(-). On the basis of potential-of-mean-force (PMF) calculations, stable conformations had distorted 3-fold symmetry and supported either one or zero encapsulated water molecules. The conformation with an encapsulated water molecule is calculated to be lower in free energy than the conformation with an empty cavity (ΔG = 1.2 kcal/mol) and is the calculated free-energy minimum in solution. CO2 molecule partitioning into the cavity is shown to be very facile, proceeding with a barrier of 1.6 kcal/mol from a weak encounter complex which stabilizes the species by about 1.0 kcal/mol. The stabilization energy of CO2 is calculated to be larger than that of H2O (ΔΔG = 1.4 kcal/mol), suggesting that the complex will preferentially encapsulate CO2 in solution. In contrast, the PMF for a bicarbonate anion entering the cavity is calculated to be repulsive in all nonbonding regions of the cavity, due to the diameter of the calix[6]arene walls. Geometry optimization of the Zn-bound hydroxide complex with an encapsulated CO2 molecule showed that multiple noncovalent interactions direct the reactants into optimal position for nucleophilic addition to occur. The calixarene complex is a structural mimic of the hydrophilic/hydrophobic divide in the enzyme, providing a functional effect for CO2 addition in the catalytic cycle. The results show that Zn-binding calix[6]arene scaffolds can be potential synthetic biomimetics for CO2 hydration catalysis, both in terms of preferentially encapsulating CO2 from solution and by spatially fixing the reactive species inside the cavity.

Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo.

PubMed

Gou, MaLing; Men, Ke; Shi, HuaShan; Xiang, MingLi; Zhang, Juan; Song, Jia; Long, JianLin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, ZhiYong

2011-04-01

Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 ± 0.011) with a mean particle size of 27.3 ± 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 ± 1.02%, and drug loading of 12.95 ± 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t(1/2) and AUC of curcumin in vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesis in vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cells in vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg(-1) curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

Nanoparticles as a Novel Delivery Vehicle for Therapeutics Targeting Erectile Dysfunction

PubMed Central

Han, George; Tar, Moses; Kuppam, Dwaraka S. R.; Friedman, Adam; Melman, Arnold; Friedman, Joel; Davies, Kelvin P.

2010-01-01

Introduction Nanoparticles represent a potential novel mechanism for transdermal delivery of erectogenic agents directly to the penis. Aim To determine if nanoparticles encapsulating known erectogenic agents (tadalafil, sialorphin, and nitric oxide [NO]) can improve erectile function in a rat model of erectile dysfunction (ED) as a result of aging (the Sprague-Dawley retired breeder rat). Methods Nanoparticles encapsulating the erectogenic agents were applied as a gel to the glans and penile shaft of anesthetized Sprague-Dawley rats and the intracorporal pressure/blood pressure (ICP/BP) monitored for up to 2 hours with or without stimulation of the cavernous nerve. Control nanoparticles were made without encapsulating erectogenic agents and applied in a similar manner in separate experiments. Results Nanoparticles encapsulating NO caused spontaneous visible erections in the rat, with an average time of onset of 4.5 minutes, duration of 1.42 minutes, and ICP/BP of 0.67 ± 0.14. The sialorphin nanoparticles also caused visible spontaneous erections after an average of 4.5 minutes, with a duration of 8 minutes and ICP/BP ratio of 0.72 ± 0.13. The difference in the erectile response between groups of animals treated with NO or sialorphin nanoparticles was significantly different from the control group treated with empty nanoparticles (P < 0.05) Tadalafil nanoparticles showed a significant increase in the mean ICP/BP (0.737 ± 0.029) following stimulation of the cavernous nerve (4 mA) 1 hour after application of the nanoparticles with a visibly improved erectile response. Conclusions Nanoparticles encapsulating three different erectogenic agents resulted in increased erectile function when applied to the penis of a rat model of ED. Nanoparticles represent a potential novel route for topical delivery of erectogenic agents which could improve the safety profile for existing orally administered drugs by avoiding effects of absorption and first-pass metabolism, and would be less hazardous than injection. PMID:19765204

Nanoparticles as a novel delivery vehicle for therapeutics targeting erectile dysfunction.

PubMed

Han, George; Tar, Moses; Kuppam, Dwaraka S R; Friedman, Adam; Melman, Arnold; Friedman, Joel; Davies, Kelvin P

2010-01-01

Nanoparticles represent a potential novel mechanism for transdermal delivery of erectogenic agents directly to the penis. To determine if nanoparticles encapsulating known erectogenic agents (tadalafil, sialorphin, and nitric oxide [NO]) can improve erectile function in a rat model of erectile dysfunction (ED) as a result of aging (the Sprague-Dawley retired breeder rat). Nanoparticles encapsulating the erectogenic agents were applied as a gel to the glans and penile shaft of anesthetized Sprague-Dawley rats and the intracorporal pressure/blood pressure (ICP/BP) monitored for up to 2 hours with or without stimulation of the cavernous nerve. Control nanoparticles were made without encapsulating erectogenic agents and applied in a similar manner in separate experiments. Nanoparticles encapsulating NO caused spontaneous visible erections in the rat, with an average time of onset of 4.5 minutes, duration of 1.42 minutes, and ICP/BP of 0.67 +/- 0.14. The sialorphin nanoparticles also caused visible spontaneous erections after an average of 4.5 minutes, with a duration of 8 minutes and ICP/BP ratio of 0.72 +/- 0.13. The difference in the erectile response between groups of animals treated with NO or sialorphin nanoparticles was significantly different from the control group treated with empty nanoparticles (P < 0.05) Tadalafil nanoparticles showed a significant increase in the mean ICP/BP (0.737 +/- 0.029) following stimulation of the cavernous nerve (4 mA) 1 hour after application of the nanoparticles with a visibly improved erectile response. Nanoparticles encapsulating three different erectogenic agents resulted in increased erectile function when applied to the penis of a rat model of ED. Nanoparticles represent a potential novel route for topical delivery of erectogenic agents which could improve the safety profile for existing orally administered drugs by avoiding effects of absorption and first-pass metabolism, and would be less hazardous than injection.

Effect of liposomal formulations and immunostimulating peptidoglycan monomer (PGM) on the immune reaction to ovalbumin in mice.

PubMed

Habjanec, Lidija; Frkanec, Ruza; Halassy, Beata; Tomasić, Jelka

2006-01-01

The adjuvant activity of liposomes and immunostimulating peptidoglycan monomer (PGM) in different formulations has been studied in mice model using ovalbumin (OVA) as an antigen. PGM is a natural compound of bacterial origin with well-defined chemical structure: GlcNAc-MurNAc-L-Ala-D-isoGln-mesoDpm(epsilonNH2)-D-Ala-D-Ala. It is a non-toxic, non-pyrogenic, and water-soluble immunostimulator. The aim of this study was to investigate the influence of different liposomal formulations of OVA, with or without PGM, on the production of total IgG, as well as of IgG1 and IgG2a subclasses of OVA-specific antibodies (as indicators of Th2 and Th1 type of immune response, respectively). CBA mice were immunized s.c. with OVA mixed with liposomes, OVA with PGM mixed with liposomes, OVA encapsulated into liposomes and OVA with PGM encapsulated into liposomes. Control groups were OVA in saline, OVA with PGM in saline, and OVA in CFA/IFA adjuvant formulation. The entrapment efficacy of OVA was monitored by HPLC method. The adjuvant activity of the mixture of OVA and empty liposomes, the mixture of OVA, PGM, and liposomes and PGM encapsulated with OVA into liposomes on production of total anti-OVA IgG was demonstrated. The mixture of PGM and liposomes exhibited additive immunostimulating effect on the production of antigen-specific IgGs. The analysis of IgG subclasses revealed that encapsulation of OVA into liposomes favors the stimulation of IgG2a antibodies, indicating the switch toward the Th1 type of immune response. When encapsulated into liposomes or mixed with liposomes, PGM induced a switch from Th1 to Th2 type of immune response. It could be concluded that appropriate formulations of antigen, PGM, and liposomes differently affect the humoral immune response and direct the switch in the type of immune response (Th1/Th2).

Asset retirement obligations: a reporting concern for healthcare facilities.

PubMed

Berg, Gary G; Bayes, Paul E; Morgan, Robert G

2008-11-01

FASB statements and SEC guidelines give direction as to how healthcare organizations should account for their asset retirement obligations (AROs) where environmental issues are concerned. A key consideration is that current costs associated with environmental problems, such as encapsulating asbestos, are to be accounted for as part of an asset's cost and depreciated over the asset's remaining life.

High voltage photo-switch package module having encapsulation with profiled metallized concavities

DOEpatents

Sullivan, James S; Sanders, David M; Hawkins, Steven A; Sampayan, Stephen A

2015-05-05

A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces metalized with first metallic layers formed thereon, and encapsulated with a dielectric encapsulation material such as for example epoxy. The first metallic layers are exposed through the encapsulation via encapsulation concavities which have a known contour profile, such as a Rogowski edge profile. Second metallic layers are then formed to line the concavities and come in contact with the first metal layer, to form profiled and metalized encapsulation concavities which mitigate enhancement points at the edges of electrodes matingly seated in the concavities. One or more optical waveguides may also be bonded to the substrate for coupling light into the photo-conductive wafer, with the encapsulation also encapsulating the waveguides.

Flexible packaging for microelectronic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Benjamin John; Nielson, Gregory N.; Cruz-Campa, Jose Luis

An apparatus, method, and system, the apparatus and system including a flexible microsystems enabled microelectronic device package including a microelectronic device positioned on a substrate; an encapsulation layer encapsulating the microelectronic device and the substrate; a protective layer positioned around the encapsulating layer; and a reinforcing layer coupled to the protective layer, wherein the substrate, encapsulation layer, protective layer and reinforcing layer form a flexible and optically transparent package around the microelectronic device. The method including encapsulating a microelectronic device positioned on a substrate within an encapsulation layer; sealing the encapsulated microelectronic device within a protective layer; and coupling themore » protective layer to a reinforcing layer, wherein the substrate, encapsulation layer, protective layer and reinforcing layer form a flexible and optically transparent package around the microelectronic device.« less

Social encapsulation of beetle parasites by Cape honeybee colonies (Apis mellifera capensis Esch.)

NASA Astrophysics Data System (ADS)

Neumann, P.; Pirk, C. W. W.; Hepburn, H. R.; Solbrig, A. J.; Ratnieks, F. L. W.; Elzen, P. J.; Baxter, J. R.

2001-05-01

Worker honeybees (Apis mellifera capensis) encapsulate the small hive beetle (Aethina tumida), a nest parasite, in propolis (tree resin collected by the bees). The encapsulation process lasts 1-4 days and the bees have a sophisticated guarding strategy for limiting the escape of beetles during encapsulation. Some encapsulated beetles died (4.9%) and a few escaped (1.6%). Encapsulation has probably evolved because the small hive beetle cannot easily be killed by the bees due to its hard exoskeleton and defensive behaviour.

Design Evolutuion of Hot Isotatic Press Cans for NTP Cermet Fuel Fabrication

NASA Technical Reports Server (NTRS)

Mireles, O. R.; Broadway, J.; Hickman, R.

2014-01-01

Nuclear Thermal Propulsion (NTP) is under consideration for potential use in deep space exploration missions due to desirable performance properties such as a high specific impulse (> 850 seconds). Tungsten (W)-60vol%UO2 cermet fuel elements are under development, with efforts emphasizing fabrication, performance testing and process optimization to meet NTP service life requirements [1]. Fuel elements incorporate design features that provide redundant protection from crack initiation, crack propagation potentially resulting in hot hydrogen (H2) reduction of UO2 kernels. Fuel erosion and fission product retention barriers include W coated UO2 fuel kernels, W clad internal flow channels and fuel element external W clad resulting in a fully encapsulated fuel element design as shown.

Catheter-based photoacoustic endoscope

PubMed Central

Yang, Joon-Mo; Li, Chiye; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk; Wang, Lihong V.

2014-01-01

Abstract. We report a flexible shaft-based mechanical scanning photoacoustic endoscopy (PAE) system that can be potentially used for imaging the human gastrointestinal tract via the instrument channel of a clinical video endoscope. The development of such a catheter endoscope has been an important challenge to realize the technique’s benefits in clinical settings. We successfully implemented a prototype PAE system that has a 3.2-mm diameter and 2.5-m long catheter section. As the instrument’s flexible shaft and scanning tip are fully encapsulated in a plastic catheter, it easily fits within the 3.7-mm diameter instrument channel of a clinical video endoscope. Here, we demonstrate the intra-instrument channel workability and in vivo animal imaging capability of the PAE system. PMID:24887743

Scattering Properties of Heterogeneous Mineral Particles with Absorbing Inclusions

NASA Technical Reports Server (NTRS)

Dlugach, Janna M.; Mishchenko, Michael I.

2015-01-01

We analyze the results of numerically exact computer modeling of scattering and absorption properties of randomly oriented poly-disperse heterogeneous particles obtained by placing microscopic absorbing grains randomly on the surfaces of much larger spherical mineral hosts or by imbedding them randomly inside the hosts. These computations are paralleled by those for heterogeneous particles obtained by fully encapsulating fractal-like absorbing clusters in the mineral hosts. All computations are performed using the superposition T-matrix method. In the case of randomly distributed inclusions, the results are compared with the outcome of Lorenz-Mie computations for an external mixture of the mineral hosts and absorbing grains. We conclude that internal aggregation can affect strongly both the integral radiometric and differential scattering characteristics of the heterogeneous particle mixtures.

Testing Orions Fairing Separation System

NASA Technical Reports Server (NTRS)

Martinez, Henry; Cloutier, Chris; Lemmon, Heber; Rakes, Daniel; Oldham, Joe; Schlagel, Keith

2014-01-01

Traditional fairing systems are designed to fully encapsulate and protect their payload from the harsh ascent environment including acoustic vibrations, aerodynamic forces and heating. The Orion fairing separation system performs this function and more by also sharing approximately half of the vehicle structural load during ascent. This load-share condition through launch and during jettison allows for a substantial increase in mass to orbit. A series of component-level development tests were completed to evaluate and characterize each component within Orion's unique fairing separation system. Two full-scale separation tests were performed to verify system-level functionality and provide verification data. This paper summarizes the fairing spring, Pyramidal Separation Mechanism and forward seal system component-level development tests, system-level separation tests, and lessons learned.

Development and evaluation of resveratrol, Vitamin E, and epigallocatechin gallate loaded lipid nanoparticles for skin care applications.

PubMed

Chen, Jin; Wei, Ning; Lopez-Garcia, Maria; Ambrose, Dianna; Lee, Jason; Annelin, Colin; Peterson, Teresa

2017-08-01

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been studied as potential carriers for both dermal and transdermal drug delivery. SLN contain lipid droplets that are fully crystallized and have a highly-ordered crystalline structure. NLC are modified SLN in which the lipid phase contains both solid and liquid lipids at room temperature. SLN and NLC are thought to combine the advantages of polymeric particles, liposomes and emulsions. Therefore they provide high encapsulation percentages, better protection for incorporated actives and allow for control of desired release profile. In this work, Resveratrol, Vitamin E (VE), and Epigallocatechin Gallate (EGCG) all potent antioxidants known to provide protection to the skin, were formulated into lipid nanoparticles. Several different formulations were successfully developed and demonstrated high uniformity and stability. Both resveratrol and VE lipid nanoparticles provided effective protection of actives against UV induced degradation. However, lipid nanoparticles did not show protection from UV degradation for EGCG in this work. An active release study exhibited a sustained release of resveratrol over 70% after 24h. Skin penetration studies showed that lipid nanoparticles directionally improved the penetration of resveratrol through the stratum corneum. Our findings suggest that lipid nanoparticles are promising viable carriers for the delivery of resveratrol and VE to provide longlasting antioxidant benefits to the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

Encapsulation of bioactive compound from extracted jasmine flower using β-Cyclodextrin via electrospray

NASA Astrophysics Data System (ADS)

Rahmam., S.; Naim., M. N.; Ng., E.; Mokhtar, M. Nn; Abu Bakar, N. F.

2016-06-01

The ability of electrospray to encapsulate the bioactive compound extracted from Jasmine flower with β-Cyclodextrion (β-CD) without any thermal-assisted processing was demonstrated in this study. The extraction of Jasmine compound were conducted using sonicator at 70 000 Hz, for 10 minutes and followed by mixing of the filtered compound with β-CD. Then, the mixture was electrosprayed under a stable Taylor cone jet mode at the voltage of 4 - 5 kV, with flow rate of 0.2 ml/hour. The aluminum substrate that used for collecting the deposit was placed at 30 cm from the needle's tip to allow the occurrence of evaporation and droplet fission until the droplet transform to solid particles. Characteristics of solidified bioactive compound from Jasmine flower (non-encapsulated compound) and solidified bioactive compound with β-CD (encapsulated compound) were studied in this work. From SEM images, it can be observed that the particles size distribution of encapsulated compound deposits have better deposition array and did not aggregate with each other compared to the non-encapsulated compound. FE-SEM images of encapsulated compound deposits indicate more solid crystal looks while non-encapsulated compound was obtained in the porous form. The electrospray process in this work has successfully encapsulated the Jasmine compound with β-CD without any thermal-assisted process. The encapsulation occurrence was determined using FTIR analysis. Identical peaks that referred to the β-CD were found on the encapsulated compound demonstrated that most deposits were encapsulated with β-CD.

Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

NASA Astrophysics Data System (ADS)

Li, Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

2009-02-01

Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, Trevor

The central focus of the work performed under this award has been to develop the bacteriophage P22 viral capsid as a vehicle for the encapsulation of catalyticaly active cargo materials and study their utility towards economic energy harvesting systems. We have demonstrated that the capsid of the bacteriophage P22 can be used to genetically program the assembly and encapsulation of a range of inorganic nanoparticles and protein cargoes. The P22 capsid uses a scaffold protein (SP) to direct the assembly of its coat protein (CP) into icosahedral capsids. By creating a genetic fusion of a desired cargo enzyme or amore » small peptide that can act as a nucleation site for subsequent NP growth, we have demonstrated the co-assembly of these SP-fusions and CP into stable “nano-reactors”. The cargo is sequestered inside the engineered capsid and can either be used directly as a nanocatalyst or for the nucleation and growth of inorganic or organic nanoparticles or polymers. The synthetic cargos (NP or polymers) were shown to have photocatalytic activity. The time dependent photophysics of a select few of these systems were studied to determine the underlying mechanisms and efficiency of light harversting. Enzyme cargos encapsulated within the P22 were thermally activated catalysts and their kinetic behavior was characterized. During the course of this work we have demonstrated that the method is a robust means to harness biology for materials applications and have initiated work into assembling the P22 nanoreactors into hierarchically ordered materials. The successful implementation of the work performed under this DOE grant provides us with a great deal of knowledge and a library of components to go forward towards the development of bioinspired catalytic materials for energy harvesting.« less

Ki-67 as a molecular target for therapy in an in vitro three-dimensional model for ovarian cancer.

PubMed

Rahmanzadeh, Ramtin; Rai, Prakash; Celli, Jonathan P; Rizvi, Imran; Baron-Lühr, Bettina; Gerdes, Johannes; Hasan, Tayyaba

2010-11-15

Targeting molecular markers and pathways implicated in cancer cell growth is a promising avenue for developing effective therapies. Although the Ki-67 protein (pKi-67) is a key marker associated with aggressively proliferating cancer cells and poor prognosis, its full potential as a therapeutic target has never before been successfully shown. In this regard, its nuclear localization presents a major hurdle because of the need for intracellular and intranuclear delivery of targeting and therapeutic moieties. Using a liposomally encapsulated construct, we show for the first time the specific delivery of a Ki-67-directed antibody and subsequent light-triggered death in the human ovarian cancer cell line OVCAR-5. Photoimmunoconjugate-encapsulating liposomes (PICEL) were constructed from anti-pKi-67 antibodies conjugated to fluorescein 5(6)-isothiocyanate, as a photoactivatable agent, followed by encapsulation in noncationic liposomes. Nucleolar localization of the PICELs was confirmed by confocal imaging. Photodynamic activation with PICELs specifically killed pKi-67-positive cancer cells both in monolayer and in three-dimensional (3D) cultures of OVCAR-5 cells, with the antibody TuBB-9 targeting a physiologically active form of pKi-67 but not with MIB-1, directed to a different epitope. This is the first demonstration of (a) the exploitation of Ki-67 as a molecular target for therapy and (b) specific delivery of an antibody to the nucleolus in monolayer cancer cells and in an in vitro 3D model system. In view of the ubiquity of pKi-67 in proliferating cells in cancer and the specificity of targeting in 3D multicellular acini, these findings are promising and the approach merits further investigation. Copyright © 2010 AACR.

Ki-67 as a molecular target for therapy in an in vitro 3D model for ovarian cancer

PubMed Central

Rahmanzadeh, Ramtin; Rai, Prakash; Celli, Jonathan P.; Rizvi, Imran; Baron-Lühr, Bettina; Gerdes, Johannes; Hasan, Tayyaba

2010-01-01

Targeting molecular markers and pathways implicated in cancer cell growth is a promising avenue for developing effective therapies. Although the Ki-67 protein (pKi-67) is a key marker associated with aggressively proliferating cancer cells and poor prognosis, its full potential as a therapeutic target has never before been successfully demonstrated. In this regard, its nuclear localization presents a major hurdle because of the need for intracellular and intranuclear delivery of targeting and therapeutic moieties. Using a liposomally encapsulated construct, we demonstrate for the first time, the specific delivery of a Ki-67 directed antibody and subsequent light-triggered death in a human ovarian cancer cell line OVCAR-5. Photoimmunoconjugate encapsulating liposomes (PICELs) were constructed from anti-pKi-67 antibodies conjugated to fluorescein isothiocyanate, as a photoactivatable agent followed by encapsulation in non-cationic liposomes. Nucleolar localization of the PICELs was confirmed by confocal imaging. Photodynamic activation with PICELs specifically killed pKi-67 positive cancer cells both in monolayer and in 3D cultures of OVCAR-5 cells with the antibody TuBB-9 targeting a physiologically active form of pKi-67 but not with MIB-1, directed to a different epitope. This is the first demonstration of: - 1. the exploitation of Ki-67 as a molecular target for therapy and - 2. specific delivery of an antibody to the nucleolus in monolayer cancer cells and in an in vitro 3D model system. In view of the ubiquity of pKi-67 in proliferating cells in cancer and the specificity of targeting in 3D multicellular acini, these findings are promising and the approach merits further investigation. PMID:21045152

Accelerated/abbreviated test methods of the low-cost silicon solar array project. Study 4, task 3: Encapsulation

NASA Technical Reports Server (NTRS)

Kolyer, J. M.; Mann, N. R.

1977-01-01

Methods of accelerated and abbreviated testing were developed and applied to solar cell encapsulants. These encapsulants must provide protection for as long as 20 years outdoors at different locations within the United States. Consequently, encapsulants were exposed for increasing periods of time to the inherent climatic variables of temperature, humidity, and solar flux. Property changes in the encapsulants were observed. The goal was to predict long term behavior of encapsulants based upon experimental data obtained over relatively short test periods.

Direct 3D bioprinting of perfusable vascular constructs using a blend bioink.

PubMed

Jia, Weitao; Gungor-Ozkerim, P Selcan; Zhang, Yu Shrike; Yue, Kan; Zhu, Kai; Liu, Wanjun; Pi, Qingment; Byambaa, Batzaya; Dokmeci, Mehmet Remzi; Shin, Su Ryon; Khademhosseini, Ali

2016-11-01

Despite the significant technological advancement in tissue engineering, challenges still exist towards the development of complex and fully functional tissue constructs that mimic their natural counterparts. To address these challenges, bioprinting has emerged as an enabling technology to create highly organized three-dimensional (3D) vascular networks within engineered tissue constructs to promote the transport of oxygen, nutrients, and waste products, which can hardly be realized using conventional microfabrication techniques. Here, we report the development of a versatile 3D bioprinting strategy that employs biomimetic biomaterials and an advanced extrusion system to deposit perfusable vascular structures with highly ordered arrangements in a single-step process. In particular, a specially designed cell-responsive bioink consisting of gelatin methacryloyl (GelMA), sodium alginate, and 4-arm poly(ethylene glycol)-tetra-acrylate (PEGTA) was used in combination with a multilayered coaxial extrusion system to achieve direct 3D bioprinting. This blend bioink could be first ionically crosslinked by calcium ions followed by covalent photocrosslinking of GelMA and PEGTA to form stable constructs. The rheological properties of the bioink and the mechanical strengths of the resulting constructs were tuned by the introduction of PEGTA, which facilitated the precise deposition of complex multilayered 3D perfusable hollow tubes. This blend bioink also displayed favorable biological characteristics that supported the spreading and proliferation of encapsulated endothelial and stem cells in the bioprinted constructs, leading to the formation of biologically relevant, highly organized, perfusable vessels. These characteristics make this novel 3D bioprinting technique superior to conventional microfabrication or sacrificial templating approaches for fabrication of the perfusable vasculature. We envision that our advanced bioprinting technology and bioink formulation may also have significant potentials in engineering large-scale vascularized tissue constructs towards applications in organ transplantation and repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

Encapsulation of single cells on a microfluidic device integrating droplet generation with fluorescence-activated droplet sorting.

PubMed

Wu, Liang; Chen, Pu; Dong, Yingsong; Feng, Xiaojun; Liu, Bi-Feng

2013-06-01

Encapsulation of single cells is a challenging task in droplet microfluidics due to the random compartmentalization of cells dictated by Poisson statistics. In this paper, a microfluidic device was developed to improve the single-cell encapsulation rate by integrating droplet generation with fluorescence-activated droplet sorting. After cells were loaded into aqueous droplets by hydrodynamic focusing, an on-flight fluorescence-activated sorting process was conducted to isolate droplets containing one cell. Encapsulation of fluorescent polystyrene beads was investigated to evaluate the developed method. A single-bead encapsulation rate of more than 98 % was achieved under the optimized conditions. Application to encapsulate single HeLa cells was further demonstrated with a single-cell encapsulation rate of 94.1 %, which is about 200 % higher than those obtained by random compartmentalization. We expect this new method to provide a useful platform for encapsulating single cells, facilitating the development of high-throughput cell-based assays.

Issues deserve attention in encapsulating probiotics: Critical review of existing literature.

PubMed

Chen, Jun; Wang, Qi; Liu, Cheng-Mei; Gong, Joshua

2017-04-13

Probiotic bacteria are being increasingly added to food for developing products with health-promoting properties. However, the efficacy of probiotics in commercial products is often questioned due to the loss of their viability during shelf storage and in human gastrointestinal tracts. Encapsulation of probiotics has been expected to provide protection to probiotics, but not many commercial products contain encapsulated and viable probiotic cells owing to various reasons. To promote the development and application of encapsulation technologies, this paper has critically reviewed previous publications with a focus on the areas where studies have fallen short, including insufficient consideration of structural effects of encapsulating material, general defects in encapsulating methods and issues in evaluation methodologies and risk assessments for application. Corresponding key issues that require further studies are highlighted. Some emerging trends in the field, such as current treads in encapsulating material and recently advanced encapsulation techniques, have also been discussed.

Selective encapsulation by Janus particles

NASA Astrophysics Data System (ADS)

Li, Wei; Ruth, Donovan; Gunton, James D.; Rickman, Jeffrey M.

2015-06-01

We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored, as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.

Microfluidic approach for encapsulation via double emulsions.

PubMed

Wang, Wei; Zhang, Mao-Jie; Chu, Liang-Yin

2014-10-01

Double emulsions, with inner drops well protected by the outer shells, show great potential as compartmentalized systems to encapsulate multiple components for protecting actives, masking flavor, and targetedly delivering and controllably releasing drugs. Precise control of the encapsulation characteristics of each component is critical to achieve an optimal therapeutic efficacy for pharmaceutical applications. Such controllable encapsulation can be realized by using microfluidic approaches for producing monodisperse double emulsions with versatile and controllable structures as the encapsulation system. The size, number and composition of the emulsion drops can be accurately manipulated for optimizing the encapsulation of each component for pharmaceutical applications. In this review, we highlight the outstanding advantages of controllable microfluidic double emulsions for highly efficient and precisely controllable encapsulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Photovoltaic module encapsulation design and materials selection, volume 1

NASA Technical Reports Server (NTRS)

Cuddihy, E.; Carroll, W.; Coulbert, C.; Gupta, A.; Liang, R. H.

1982-01-01

Encapsulation material system requirements, material selection criteria, and the status and properties of encapsulation materials and processes available are presented. Technical and economic goals established for photovoltaic modules and encapsulation systems and their status are described. Available encapsulation technology and data are presented to facilitate design and material selection for silicon flat plate photovoltaic modules, using the best materials available and processes optimized for specific power applications and geographic sites. The operational and environmental loads that encapsulation system functional requirements and candidate design concepts and materials that are identified to have the best potential to meet the cost and performance goals for the flat plate solar array project are described. Available data on encapsulant material properties, fabrication processing, and module life and durability characteristics are presented.

Modification of polyelectrolyte microcapsules into a container for the low molecular weight compounds

NASA Astrophysics Data System (ADS)

Goryacheva, O. A.; Gao, H.; Sukhorukov, G. B.

2018-04-01

Polyelectrolyte microcapsules are one of the most successful developments in the direction of target drug delivery. Nevertheless, to encapsulate low molecular weight compounds and to deliver the targeted drugs it is necessary to modify the surface of the microcapsules. Silica nanostructures obtained as result of hydrolysis of (3-Aminopropyl)- triethoxysilane (APTES) were used for the modification of the microcapsules. This material shows no toxic effect on cells and is capable of biodegradation. Amino-groups in the structure of APTES make it possible for further direct bioconjugation.

Encapsulation of adenovirus serotype 5 in anionic lecithin liposomes using a bead-based immunoprecipitation technique enhances transfection efficiency.

PubMed

Mendez, Natalie; Herrera, Vanessa; Zhang, Lingzhi; Hedjran, Farah; Feuer, Ralph; Blair, Sarah L; Trogler, William C; Reid, Tony R; Kummel, Andrew C

2014-11-01

Oncolytic viruses (OVs) constitute a promising class of cancer therapeutics which exploit validated genetic pathways known to be deregulated in many cancers. To overcome an immune response and to enhance its potential use to treat primary and metastatic tumors, a method for liposomal encapsulation of adenovirus has been developed. The encapsulation of adenovirus in non-toxic anionic lecithin-cholesterol-PEG liposomes ranging from 140 to 180 nm in diameter have been prepared by self-assembly around the viral capsid. The encapsulated viruses retain their ability to infect cancer cells. Furthermore, an immunoprecipitation (IP) technique has shown to be a fast and effective method to extract non-encapsulated viruses and homogenize the liposomes remaining in solution. 78% of adenovirus plaque forming units were encapsulated and retained infectivity after IP processing. Additionally, encapsulated viruses have shown enhanced transfection efficiency up to 4 × higher compared to non-encapsulated Ads. Extracting non-encapsulated viruses from solution may prevent an adverse in vivo immune response and may enhance treatment for multiple administrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Encapsulation of Adenovirus Serotype 5 in Anionic Lecithin Liposomes using a Bead-Based Immunoprecipitation Technique Enhances Transfection Efficiency

PubMed Central

Mendez, N.; Herrera, V.; Zhang, L.; Hedjran, F.; Feuer, R.; Blair, S.; Trogler, W.; Reid, T.

2014-01-01

Oncolytic viruses (OVs) constitute a promising class of cancer therapeutics which exploit validated genetic pathways known to be deregulated in many cancers. To overcome an immune response and to enhance its potential use to treat primary and metastatic tumors, a method for liposomal encapsulation of adenovirus has been developed. The encapsulation of adenovirus in non-toxic anionic lecithin-cholesterol-PEG liposomes ranging from 140–180nm in diameter have been prepared by self-assembly around the viral capsid. The encapsulated viruses retain their ability to infect cancer cells. Furthermore, an immunoprecipitation (IP) technique has shown to be a fast and effective method to extract non-encapsulated viruses and homogenize the liposomes remaining in solution. 78% of adenovirus plaque forming units were encapsulated and retained infectivity after IP processing. Additionally, encapsulated viruses have shown enhanced transfection efficiency up to 4× higher compared to non-encapsulated Ads. Extracting non-encapsulated viruses from solution may prevent an adverse in vivo immune response and may enhance treatment for multiple administrations. PMID:25154663

Encapsulation optimization of lemon balm antioxidants in calcium alginate hydrogels.

PubMed

Najafi-Soulari, Samira; Shekarchizadeh, Hajar; Kadivar, Mahdi

2016-11-01

Calcium alginate hydrogel beads were used to encapsulate lemon balm extract. Chitosan layer was used to investigate the effect of hydrogel coating. To determine the interactions of antioxidant compounds of extract with encapsulation materials and its stability, microstructure of hydrogel beads was thoroughly monitored using scanning electron microscopy and Fourier transform infrared (FTIR). Total polyphenols content and antiradical activity of lemon balm extract were also evaluated before and after encapsulation. Three significant parameters (lemon balm extract, sodium alginate, and calcium chloride concentrations) were optimized by response surface methodology to obtain maximum encapsulation efficiency. The FTIR spectra showed no interactions between extract and polymers as there were no new band in spectra of alginate hydrogel after encapsulation of active compounds of lemon balm extract. The antioxidant activity of lemon balm extract did not change after encapsulation. Therefore, it was found that alginate is a suitable material for encapsulation of natural antioxidants. Sodium alginate solution concentration, 1.84%, lemon balm extract concentration, 0.4%, and calcium chloride concentration, 0.2% was determined to be the optimum condition to reach maximum encapsulation efficiency.

Encapsulation of Citronellal from Citronella Oil using β-Cyclodextrin and Its Application as Mosquito (Aedes aegypti) Repellent

NASA Astrophysics Data System (ADS)

Pujiastuti, A.; Cahyono, E.; Sumarni, W.

2017-04-01

Mosquito (Aedes aegypti) is a threat to human health due to its capability to spread dengue fever. Citronellal in citronella oil is one ofnatural active compound that has repellent activity. Essential oil is a sensitive material whichiseasy to degrade. Encapsulation is coating technology use to avoid essential oil from degradation problems. β-Cyclodextrin is frequently used as acoating material in encapsulation. The aims of this study wereto prepare the citronellal encapsulation and to evaluate its control-released and repellency. In this study, encapsulated citronellal was prepared using 83.65% citronellal and encapsulation were prepared with the theemulsion-based method and dried using freeze-dryer. The best-controlled release was performed in citronellal encapsulate with a weight ratio of 1:1 (citronellal : β-Cyclodextrin). The morphology of encapsulated citronellal was analyzed using SEM. SEM result showed it has three dimensions random shape and agglomerate in some part with thebrighter spot. Citronellal encapsulate showed the highest repellent effect at 84,67% for 5 minutes in mosquito repellency test although it has lower result compared with citronellal inliquid form.

Uncoordinated MAC for Adaptive Multi Beam Directional Networks: Analysis and Evaluation

DTIC Science & Technology

2016-08-01

control (MAC) policies for emerging systems that are equipped with fully digital antenna arrays which are capable of adaptive multi-beam directional...Adaptive Beam- forming, Multibeam, Directional Networking, Random Access, Smart Antennas I. INTRODUCTION Fully digital beamforming antenna arrays that...are capable of adaptive multi-beam communications are quickly becoming a reality. These antenna arrays allow users to form multiple simultaneous

Liposomes as protective capsules for active silica sol-gel biocomposite synthesis.

PubMed

Li, Ye; Yip, Wai Tak

2005-09-21

Using liposome to shield an enzyme from hostile chemical environments during the sol-gel formation process has resulted in a novel approach to synthesizing silica sol-gel biocomposite materials. By reporting the encapsulation of horseradish peroxidase and firefly luciferase, we demonstrate that this new protocol can produce silica biocomposites that are more active than trapping the enzymes directly into hydrogels.

Ultrasensitive thrombin detection based on direct electrochemistry of highly loaded hemoglobin spheres-encapsulated platinum nanoparticles as labels and electrocatalysts.

PubMed

Wu, Yongmei; Xu, Wenju; Bai, Lijuan; Yuan, Yali; Yi, Huayu; Chai, Yaqin; Yuan, Ruo

2013-12-15

For the first time, a sandwich-type electrochemical method was proposed for ultrasensitive thrombin (TB) detection based on direct electrochemistry of highly loaded hemoglobin spheres-encapsulated platinum nanoparticles (PtNPs@Hb) as labels and electrocatalysts. The prepared PtNPs@Hb not only exhibited good biocompatibility, excellent electrocatalytic activity, but also presented redox activity of Hb. Thus, it was employed for the fabrication of aptasensor without any extraneous redox mediators, leading to a simple preparation process for the aptasensor. The high loading of Hb spheres as redox mediators could enhance the electrochemical signal. Importantly, the synergetic electrocatalytic behavior of Hb and PtNPs toward H2O2 reduction greatly amplified the electrochemical signal, resulting in the high sensitivity of aptasensor. Consequently, under optimal conditions, the designed aptasensor exhibited a lower detection limit of 0.05 pM and wide dynamic linear range from 0.15 pM to 40 nM for TB detection. Additionally, the proposed mediator-free and signal-amplified electrochemical aptasensor showed great potential in portable and cost-effective TB sensing devices. Copyright © 2013 Elsevier B.V. All rights reserved.

Highly sensitive and selective cholesterol biosensor based on direct electron transfer of hemoglobin.

PubMed

Zhao, Changzhi; Wan, Li; Jiang, Li; Wang, Qin; Jiao, Kui

2008-12-01

A cholesterol biosensor based on direct electron transfer of a hemoglobin-encapsulated chitosan-modified glassy carbon electrode has been developed for highly sensitive and selective analysis of serum samples. Modified by films containing hemoglobin and cholesterol oxidase, the electrode was prepared by encapsulation of enzyme in chitosan matrix. The hydrogen peroxide produced by the catalytic oxidation of cholesterol by cholesterol oxidase was reduced electrocatalytically by immobilized hemoglobin and used to obtain a sensitive amperometric response to cholesterol. The linear response of cholesterol concentrations ranged from 1.00 x 10(-5) to 6.00 x 10(-4) mol/L, with a correlation coefficient of 0.9969 and estimated detection limit of cholesterol of 9.5 micromol/L at a signal/noise ratio of 3. The cholesterol biosensor can efficiently exclude interference by the commonly coexisting ascorbic acid, uric acid, dopamine, and epinephrine. The sensitivity to the change in the concentration of cholesterol as the slope of the calibration curve was 0.596 A/M. The relative standard deviation was under 4.0% (n=5) for the determination of real samples. The biosensor is satisfactory in the determination of human serum samples.

RNA extraction from self-assembling peptide hydrogels to allow qPCR analysis of encapsulated cells.

PubMed

Burgess, Kyle A; Workman, Victoria L; Elsawy, Mohamed A; Miller, Aline F; Oceandy, Delvac; Saiani, Alberto

2018-01-01

Self-assembling peptide hydrogels offer a novel 3-dimensional platform for many applications in cell culture and tissue engineering but are not compatible with current methods of RNA isolation; owing to interactions between RNA and the biomaterial. This study investigates the use of two techniques based on two different basic extraction principles: solution-based extraction and direct solid-state binding of RNA respectively, to extract RNA from cells encapsulated in four β-sheet forming self-assembling peptide hydrogels with varying net positive charge. RNA-peptide fibril interactions, rather than RNA-peptide molecular complexing, were found to interfere with the extraction process resulting in low yields. A column-based approach relying on RNA-specific binding was shown to be more suited to extracting RNA with higher purity from these peptide hydrogels owing to its reliance on strong specific RNA binding interactions which compete directly with RNA-peptide fibril interactions. In order to reduce the amount of fibrils present and improve RNA yields a broad spectrum enzyme solution-pronase-was used to partially digest the hydrogels before RNA extraction. This pre-treatment was shown to significantly increase the yield of RNA extracted, allowing downstream RT-qPCR to be performed.

Prostate-Specific Membrane Antigen-Targeted Site-Directed Antibody-Conjugated Apoferritin Nanovehicle Favorably Influences In Vivo Side Effects of Doxorubicin.

PubMed

Dostalova, Simona; Polanska, Hana; Svobodova, Marketa; Balvan, Jan; Krystofova, Olga; Haddad, Yazan; Krizkova, Sona; Masarik, Michal; Eckschlager, Tomas; Stiborova, Marie; Heger, Zbynek; Adam, Vojtech

2018-06-11

Herein, we describe the in vivo effects of doxorubicin (DOX) encapsulated in ubiquitous protein apoferritin (APO) and its efficiency and safety in anti-tumor treatment. APODOX is both passively (through Enhanced Permeability and Retention effect) and actively targeted to tumors through prostate-specific membrane antigen (PSMA) via mouse antibodies conjugated to the surface of horse spleen APO. To achieve site-directed conjugation of the antibodies, a HWRGWVC heptapeptide linker was used. The prostate cancer-targeted and non-targeted nanocarriers were tested using subcutaneously implanted LNCaP cells in athymic mice models, and compared to free DOX. Prostate cancer-targeted APODOX retained the high potency of DOX in attenuation of tumors (with 55% decrease in tumor volume after 3 weeks of treatment). DOX and non-targeted APODOX treatment caused damage to liver, kidney and heart tissues. In contrast, no elevation in liver or kidney enzymes and negligible changes were revealed by histological assessment in prostate cancer-targeted APODOX-treated mice. Overall, we show that the APO nanocarrier provides an easy encapsulation protocol, reliable targeting, high therapeutic efficiency and very low off-target toxicity, and is thus a promising delivery system for translation into clinical use.

Encapsulation of Nucleic Acids into Giant Unilamellar Vesicles by Freeze-Thaw: a Way Protocells May Form

NASA Astrophysics Data System (ADS)

Qiao, Hai; Hu, Na; Bai, Jin; Ren, Lili; Liu, Qing; Fang, Liaoqiong; Wang, Zhibiao

2017-12-01

Protocells are believed to consist of a lipid membrane and encapsulated nucleic acid. As the lipid membrane is impermeable to macromolecules like nucleic acids, the processes by which nucleic acids become encapsulated inside lipid membrane compartments are still unknown. In this paper, a freeze-thaw method was modified and applied to giant unilamellar vesicles (GUVs) and deoxyribonucleic acid (DNA) in mixed solution resulting in the efficient encapsulation of 6.4 kb plasmid DNA and similar length linear DNA into GUVs. The mechanism of encapsulation was followed by observing the effect of freeze-thaw temperatures on GUV morphological change, DNA encapsulation and ice crystal formation, and analyzing their correlation. Following ice crystal formation, the shape of spherical GUVs was altered and membrane integrity was damaged and this was found to be a necessary condition for encapsulation. Heating alone had no effects on DNA encapsulation, but was helpful for restoring the spherical shape and membrane integrity of GUVs damaged during freezing. These results suggested that freeze-thaw could promote the encapsulation of DNA into GUVs by a mechanism: the vesicle membrane was breached by ice crystal formation during freezing, DNA entered into damaged GUVs through these membrane gaps and was encapsulated after the membrane was resealed during the thawing process. The process described herein therefore describes a simple way for the encapsulation of nucleic acids and potentially other macromolecules into lipid vesicles, a process by which early protocells might have formed.

Electrostatic assembly of binary nanoparticle superlattices using protein cages

NASA Astrophysics Data System (ADS)

Kostiainen, Mauri A.; Hiekkataipale, Panu; Laiho, Ari; Lemieux, Vincent; Seitsonen, Jani; Ruokolainen, Janne; Ceci, Pierpaolo

2013-01-01

Binary nanoparticle superlattices are periodic nanostructures with lattice constants much shorter than the wavelength of light and could be used to prepare multifunctional metamaterials. Such superlattices are typically made from synthetic nanoparticles, and although biohybrid structures have been developed, incorporating biological building blocks into binary nanoparticle superlattices remains challenging. Protein-based nanocages provide a complex yet monodisperse and geometrically well-defined hollow cage that can be used to encapsulate different materials. Such protein cages have been used to program the self-assembly of encapsulated materials to form free-standing crystals and superlattices at interfaces or in solution. Here, we show that electrostatically patchy protein cages--cowpea chlorotic mottle virus and ferritin cages--can be used to direct the self-assembly of three-dimensional binary superlattices. The negatively charged cages can encapsulate RNA or superparamagnetic iron oxide nanoparticles, and the superlattices are formed through tunable electrostatic interactions with positively charged gold nanoparticles. Gold nanoparticles and viruses form an AB8fcc crystal structure that is not isostructural with any known atomic or molecular crystal structure and has previously been observed only with large colloidal polymer particles. Gold nanoparticles and empty or nanoparticle-loaded ferritin cages form an interpenetrating simple cubic AB structure (isostructural with CsCl). We also show that these magnetic assemblies provide contrast enhancement in magnetic resonance imaging.

Preparation of Surlyn films reinforced with cellulose nanofibres and feasibility of applying the transparent composite films for organic photovoltaic encapsulation

PubMed Central

Lertngim, Anantaya; Phiriyawirut, Manisara; Yuwawech, Kitti; Sangkhun, Weradesh; Kumnorkaew, Pisist; Muangnapoh, Tanyakorn

2017-01-01

This research concerns the development of Surlyn film reinforced with micro-/nanofibrillated celluloses (MFC) for use as an encapsulant in organic photovoltaic (OPV) cells. The aim of this work was to investigate the effects of fibre types and the mixing methods on the structure–properties of the composite films. Three types of cellulose micro/nanofibrils were prepared: the as-received MFC, the dispersed MFC and the esterified MFC. The fibres were mixed with Surlyn via an extrusion process, using two different mixing methods. It was found that the extent of fibre disintegration and tensile modulus of the composite films prepared by the master-batching process was superior to that of the composite system prepared by the direct mixing method. Using the esterified MFC as a reinforcement, compatibility between polymer and the fibre increased, accompanied with the improvement of the percentage elongation of the Surlyn composite film. The percentage of light transmittance of the Surlyn/MFC films was above 88, regardless of the fibre types and fibre concentrations. The water vapour transmission rate of the Surlyn/esterified MFC film was 65% lower than that of the neat Surlyn film. This contributed to the longer lifetime of the OPV encapsulated with the Surlyn/esterified MFC film. PMID:29134083

Tailoring sub-micron PLGA particle release profiles via centrifugal fractioning

PubMed Central

Dutta, Dipankar; Salifu, Mariama; Sirianni, Rachael W.; Stabenfeldt, Sarah E.

2016-01-01

Poly(D,L-lactic-co-glycolic) acid (PLGA)-based submicron particles are uniquely posed to overcome limitations of conventional drug delivery systems. However, tailoring cargo/payload release profiles from PLGA micro/nanoparticles typically requires optimization of the multi-parameter formulation, where small changes may cause drastic shifts in the resulting release profiles. In this study, we aimed to establish whether refining the average diameter of submicron particle populations after formulation alters protein release profiles. PLGA particles were first produced via double emulsion-solvent evaporation method to encapsulate bovine serum albumin. Particles were then subjected to centrifugal fractioning protocols varying in both spin time and force to determine encapsulation efficiency and release profile of differently sized populations that originated from a single batch. We found the average particle diameter was related to marked alterations in encapsulation efficiencies (range: 36.4–49.4%), burst release (range: 15.8–49.1%), and time for total cargo release (range: 38–78 days). Our data corroborate previous reports relating PLGA particle size with such release characteristics, however, this is the first study, to our knowledge, to directly compare particle population size while holding all formulation parameters constant. In summary, centrifugal fractioning to selectively control the population distribution of sub-micron PLGA particles represents a feasible tool to tailor release characteristics. PMID:26517011

Solar receiver with integrated optics

NASA Astrophysics Data System (ADS)

Jiang, Lun; Winston, Roland

2012-10-01

The current challenge for PV/Thermal (PV/T) systems is the reduction of radiation heat loss. Compared to solar thermal selective coating, the solar cells cannot be used as an efficient thermal absorber due to their large emissivity of the encapsulation material. Many commercial PV/T products therefore require a high concentration (more than 10x) to reach an acceptable thermal efficiency for their receivers. Such a concentration system inevitably has to track or semi-track, which induces additional cost and collects only the direct radiation from the sun. We propose a new PV/T design using a vacuum encapsulated thin film cell to solve this problem. The proposed design also collects the diffuse sun light efficiently by using an external compound parabolic concentrator (XCPC). Since the transparent electrode (TCO) of thin film cell is inherently transparent in visible light and reflective beyond infrared, this design uses this layer instead of the conventional solar cell encapsulation as the outmost heat loss surface. By integrating such a vacuum design with a tube shaped absorber, we reduce the complexity of conducting the heat energy and electricity out of the device. A low concentration standalone non-tracking solar collector is proposed in this paper. We also analyzed the thermosyphon system configuration using heat transfer and ray tracing models. The economics of such a receiver are presented.

Preparation of Surlyn films reinforced with cellulose nanofibres and feasibility of applying the transparent composite films for organic photovoltaic encapsulation

NASA Astrophysics Data System (ADS)

Lertngim, Anantaya; Phiriyawirut, Manisara; Wootthikanokkhan, Jatuphorn; Yuwawech, Kitti; Sangkhun, Weradesh; Kumnorkaew, Pisist; Muangnapoh, Tanyakorn

2017-10-01

This research concerns the development of Surlyn film reinforced with micro-/nanofibrillated celluloses (MFC) for use as an encapsulant in organic photovoltaic (OPV) cells. The aim of this work was to investigate the effects of fibre types and the mixing methods on the structure-properties of the composite films. Three types of cellulose micro/nanofibrils were prepared: the as-received MFC, the dispersed MFC and the esterified MFC. The fibres were mixed with Surlyn via an extrusion process, using two different mixing methods. It was found that the extent of fibre disintegration and tensile modulus of the composite films prepared by the master-batching process was superior to that of the composite system prepared by the direct mixing method. Using the esterified MFC as a reinforcement, compatibility between polymer and the fibre increased, accompanied with the improvement of the percentage elongation of the Surlyn composite film. The percentage of light transmittance of the Surlyn/MFC films was above 88, regardless of the fibre types and fibre concentrations. The water vapour transmission rate of the Surlyn/esterified MFC film was 65% lower than that of the neat Surlyn film. This contributed to the longer lifetime of the OPV encapsulated with the Surlyn/esterified MFC film.

Acridine Orange Conjugated Polymersomes for Simultaneous Nuclear Delivery of Gemcitabine and Doxorubicin to Pancreatic Cancer Cells.

PubMed

Anajafi, Tayebeh; Scott, Michael D; You, Seungyong; Yang, Xiaoyu; Choi, Yongki; Qian, Steven Y; Mallik, Sanku

2016-03-16

Considering the systemic toxicity of chemotherapeutic agents, there is an urgent need to develop new targeted drug delivery systems. Herein, we have developed a new nuclear targeted, redox sensitive, drug delivery vehicle to simultaneously deliver the anticancer drugs gemcitabine and doxorubicin to the nuclei of pancreatic cancer cells. We prepared polymeric bilayer vesicles (polymersomes), and actively encapsulated the drug combination by the pH gradient method. A redox-sensitive polymer (PEG-S-S-PLA) was incorporated to sensitize the formulation to reducing agent concentration. Acridine orange (AO) was conjugated to the surface of the polymersomes imparting nuclear localizing property. The polymersomes' toxicity and efficacy were compared with those of a free drug combination using monolayer and three-dimensional spheroid cultures of pancreatic cancer cells. We observed that the redox sensitive, nuclear-targeted polymersomes released more than 60% of their encapsulated contents in response to 50 mM glutathione. The nanoparticles are nontoxic; however, the drug encapsulated vesicles have significant toxicity. The prepared formulation can increase the drug's therapeutic index by delivering the drugs directly to the cells' nuclei, one of the key organelles in the cells. This study is likely to initiate research in targeted nuclear delivery using other drug formulations in other types of cancers.

Synthesis of antibacterial surfaces by plasma grafting of zinc oxide based nanocomposites onto polypropylene.

PubMed

de Rancourt, Yoann; Couturaud, Benoit; Mas, André; Robin, Jean Jacques

2013-07-15

Antibacterial polymer surfaces were designed using ZnO nanoparticles as a bactericide. Mineral encapsulated nanoparticles were grafted onto activated polymer surfaces through their shells. Polypropylene (PP) surfaces were treated using an innovative process coupling core-shell technology and plasma grafting, well-known techniques commonly used to obtain active surfaces for biomedical applications. First, ZnO nanoparticles were encapsulated by (co)polymers: poly(acrylic acid) (PAA) or a poly(methyl methacrylate-co-methacrylic acid) copolymer [P(MMA-MA)]. Second, PP substrates were activated using plasma treatment. Finally, plasma-treated surfaces were immersed in solutions containing the encapsulated nanoparticles dispersed in an organic solvent and allowed to graft onto it. The presence of nanoparticles on the substrates was demonstrated using Fourier-Transform Infrared Spectroscopy (FTIR) analysis, Scanning Electron Microspcopy (SEM)/Energy-Dispersive X-ray (EDX), and Atomic Force Microscopy (AFM) studies. Indeed, the ZnO-functionalized substrates exhibited an antibacterial response in Escherichia coli adhesion tests. Moreover, this study revealed that, surprisingly, native ZnO nanoparticles without any previous functionalization could be directly grafted onto polymeric surfaces through plasma activation. The antibacterial activity of the resulting sample was shown to be comparable to that of the other samples. Copyright © 2013 Elsevier Inc. All rights reserved.

Encapsulation of mesenchymal stem cells in chitosan/β-glycerophosphate hydrogel for seeding on a novel calcium phosphate cement scaffold.

PubMed

Liu, Tao; Li, Jian; Shao, Zengwu; Ma, Kaige; Zhang, Zhicai; Wang, Baichuan; Zhang, Yannan

2018-06-01

Due to its moldability, biocompatibility, osteoconductivity and resorbability, calcium phosphate cement (CPC) is a highly promising scaffold material for orthopedic applications. However, pH changes and ionic activity during the CPC setting reaction may adversely affect cells seeded directly on CPC. Moreover, a lack of macropores in CPC limits ingrowth of new bone. The objectives of this study were to prepare macroporous CPC scaffolds via porogen leaching, using mannitol crystals as the porogen and to evaluate the in vitro proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) encapsulated in chitosan/β-glycerophosphate (C/GP) hydrogel prior to exposure to the novel CPC scaffold. MSCs were found to be adhered to the surfaces of CPC macropores via scanning electron microscopy. The viability and osteogenic differentiation of MSCs in C/GP hydrogel with or without exposure to CPC constructs containing mannitol crystals indicated that coating with C/GP hydrogel protected the cells during cement mixing and setting. In conclusion, novel, macroporous CPC scaffolds were prepared, and our data indicate that a hydrogel encapsulation-based strategy can be used to protect cells during scaffold formation. Thus, the MSC-laden CPC scaffolds show promise for the delivery of stem cells to promote bone regeneration. Copyright © 2018 IPEM. Published by Elsevier Ltd. All rights reserved.

Gallium nanoparticles facilitate phagosome maturation and inhibit growth of virulent Mycobacterium tuberculosis in macrophages.

PubMed

Choi, Seoung-Ryoung; Britigan, Bradley E; Moran, David M; Narayanasamy, Prabagaran

2017-01-01

New treatments and novel drugs are required to counter the growing problem of drug-resistant strains of Mycobacterium tuberculosis (M.tb). Our approach against drug resistant M.tb, as well as other intracellular pathogens, is by targeted drug delivery using nanoformulations of drugs already in use, as well as drugs in development. Among the latter are gallium (III) (Ga)-based compounds. In the current work, six different types of Ga and rifampin nanoparticles were prepared in such a way as to enhance targeting of M.tb infected-macrophages. They were then tested for their ability to inhibit growth of a fully pathogenic strain (H37Rv) or a non-pathogenic strain (H37Ra) of M.tb. Encapsulating Ga in folate- or mannose-conjugated block copolymers provided sustained Ga release for 15 days and significantly inhibited M.tb growth in human monocyte-derived macrophages. Nanoformulations with dendrimers encapsulating Ga or rifampin also showed promising anti-tuberculous activity. The nanoparticles co-localized with M.tb containing phagosomes, as measured by detection of mature cathepsin D (34 kDa, lysosomal hydrogenase). They also promoted maturation of the phagosome, which would be expected to increase macrophage-mediated killing of the organism. Delivery of Ga or rifampin in the form of nanoparticles to macrophages offers a promising approach for the development of new therapeutic anti-tuberculous drugs.

Gallium nanoparticles facilitate phagosome maturation and inhibit growth of virulent Mycobacterium tuberculosis in macrophages

PubMed Central

Choi, Seoung-ryoung; Britigan, Bradley E.; Moran, David M.

2017-01-01

New treatments and novel drugs are required to counter the growing problem of drug-resistant strains of Mycobacterium tuberculosis (M.tb). Our approach against drug resistant M.tb, as well as other intracellular pathogens, is by targeted drug delivery using nanoformulations of drugs already in use, as well as drugs in development. Among the latter are gallium (III) (Ga)-based compounds. In the current work, six different types of Ga and rifampin nanoparticles were prepared in such a way as to enhance targeting of M.tb infected-macrophages. They were then tested for their ability to inhibit growth of a fully pathogenic strain (H37Rv) or a non-pathogenic strain (H37Ra) of M.tb. Encapsulating Ga in folate- or mannose-conjugated block copolymers provided sustained Ga release for 15 days and significantly inhibited M.tb growth in human monocyte-derived macrophages. Nanoformulations with dendrimers encapsulating Ga or rifampin also showed promising anti-tuberculous activity. The nanoparticles co-localized with M.tb containing phagosomes, as measured by detection of mature cathepsin D (34 kDa, lysosomal hydrogenase). They also promoted maturation of the phagosome, which would be expected to increase macrophage-mediated killing of the organism. Delivery of Ga or rifampin in the form of nanoparticles to macrophages offers a promising approach for the development of new therapeutic anti-tuberculous drugs. PMID:28542623

Encapsulation of the Antioxidant R-(+)-α-Lipoic Acid in Permethylated α- and β-Cyclodextrins: Thermal and X-ray Structural Characterization of the 1:1 Inclusion Complexes.

PubMed

Caira, Mino R; Bourne, Susan A; Mzondo, Buntubonke

2017-05-23

The naturally occurring compound α-lipoic acid (ALA) is implicated in manifold critical biological roles and its potent antioxidant properties and potential for treatment of various diseases have led to its widespread use as a dietary supplement. However, shortcomings of poor aqueous solubility and low thermal stability have hampered its development as a medicinal agent, prompting the use of cyclodextrins (CDs) to address these problems. The paucity of published structural data on the nature of the interactions between ALA and CDs motivated the present study, which describes the synthesis and X-ray structural elucidation of crystalline inclusion complexes between the biologically relevant R-(+)-α-lipoic acid (RALA) and the host molecules permethylated α-CD (TMA) and permethylated β-CD (TMB). Single crystal X-ray diffraction of TMA·RALA·6H₂O and TMB·RALA revealed significantly different orientations of the RALA molecule within the TMA and TMB cavities, but in both cases the guest molecule is fully encapsulated by the respective parent host molecules and residues of CD molecules of neighboring complex units. While pure RALA melted at 46-48 °C, combined thermal analysis techniques indicated that on heating the respective complexes, the release of RALA occurred at significantly higher onset temperatures, in the range 150-170 °C.

Examining the association of DDX compounds to sedimentary organic matter

NASA Astrophysics Data System (ADS)

Weathers, N.; Rowlett, K.; Geng, Z.; Morrison, A.; White, H. K.

2016-02-01

The association of hydrophobic organic contaminants (HOCs) with sedimentary organic matter (OM) influences their mobility and bioavailability in the environment. Determining whether these associations result from mechanisms such as sorption, chemical binding or encapsulation is critical for predicting their long-term fate. The pesticide DDT (dichlorodiphenyltrichloroethane) has been previously observed to form bound residues with sedimentary OM although the mechanisms of this association are yet to be fully explored. DDT, which was sprayed ubiquitously in the 1950s and early 1960s, can still be found in the environment today along with its three major metabolites, DDE, DDD and DDMU (collectively known as DDX compounds), and therefore presents a unique opportunity to further explore its long-term associations with OM. To this end, a sediment core from a salt marsh in Dover, Delaware known to contain DDX compounds was collected. A maximum concentration of DDX compounds was found at sediment depths corresponding to the time of the widespread usage of DDT. An initial solvent extraction with toluene provided data on the loosely associated DDX fraction followed by subsequent treatments with sulfuric acid and saponification to release DDX that was encapsulated or bound to the sedimentary matrix. Determining the physical disposition of DDX compounds that persist in sediments for several decades is integral to determining the extent to which they are mobile, bioavailable or sequestered in the marsh.

A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Hyunji; Zhao, Xiaohui; Kim, Dul-Sun

2014-10-15

Highlights: • CMK-3 mesoporous carbon was synthesized as conducting reservoir for housing sulfur. • Sulfur/CMK-3 composites were prepared by two-stage thermal treatment. • The composite at 300 °C for 20 h shows improved electrochemical properties. - Abstract: Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300 °C plays an important role in the sulfur encapsulation process. With 20 h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60 h of heating time,more » sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40 h at 300 °C contained 51.3 wt.% sulfur and delivered a high initial capacity of 1375 mA h g{sup −1} at 0.1 C. Moreover, it showed good capacity retention of 704 mA h g{sup −1} at 0.1 C and 578 mA h g{sup −1} at 2 C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries.« less

Hollow Pollen Shells to Enhance Drug Delivery

PubMed Central

Diego-Taboada, Alberto; Beckett, Stephen T.; Atkin, Stephen L.; Mackenzie, Grahame

2014-01-01

Pollen grain and spore shells are natural microcapsules designed to protect the genetic material of the plant from external damage. The shell is made up of two layers, the inner layer (intine), made largely of cellulose, and the outer layer (exine), composed mainly of sporopollenin. The relative proportion of each varies according to the plant species. The structure of sporopollenin has not been fully characterised but different studies suggest the presence of conjugated phenols, which provide antioxidant properties to the microcapsule and UV (ultraviolet) protection to the material inside it. These microcapsule shells have many advantageous properties, such as homogeneity in size, resilience to both alkalis and acids, and the ability to withstand temperatures up to 250 °C. These hollow microcapsules have the ability to encapsulate and release actives in a controlled manner. Their mucoadhesion to intestinal tissues may contribute to the extended contact of the sporopollenin with the intestinal mucosa leading to an increased efficiency of delivery of nutraceuticals and drugs. The hollow microcapsules can be filled with a solution of the active or active in a liquid form by simply mixing both together, and in some cases operating a vacuum. The active payload can be released in the human body depending on pressure on the microcapsule, solubility and/or pH factors. Active release can be controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell. PMID:24638098

Selective encapsulation by Janus particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei, E-mail: wel208@mrl.ucsb.edu; Ruth, Donovan; Gunton, James D.

2015-06-28

We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored,more » as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.« less

Effect of Morphology and Size of Halloysite Nanotubes on Functional Pectin Bionanocomposites for Food Packaging Applications.

PubMed

Makaremi, Maziyar; Pasbakhsh, Pooria; Cavallaro, Giuseppe; Lazzara, Giuseppe; Aw, Yoong Kit; Lee, Sui Mae; Milioto, Stefana

2017-05-24

Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this study as potential films for food packaging applications. The two types of halloysite nanotubes were long and thin (patch) (200-30 000 nm length) and short and stubby (Matauri Bay) (50-3000 nm length) with different morphological, physical, and dispersibility properties. Both matrix (pectin) and reinforcer (halloysite nanotubes) used in this study are considered as biocompatible, natural, and low-cost materials. Various characterization tests including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, release kinetics, contact angle, and dynamic mechanical analysis were performed to evaluate the performance of the pectin films. Exceptional thermal, tensile, and contact angle properties have been achieved for films reinforced by patch halloysite nanotubes due to the patchy and lengthy nature of these tubes, which form a bird nest structure in the pectin matrix. Matauri Bay halloysite nanotubes were dispersed uniformly and individually in the matrix in low and even high halloysite nanotube concentrations. Furthermore, salicylic acid as a biocidal agent was encapsulated in the halloysite nanotubes lumen to control its release kinetics. On this basis, halloysite nanotubes/salicylic acid hybrids were dispersed into the pectin matrix to develop functional biofilms with antimicrobial properties that can be extended over time. Results revealed that shorter nanotubes (Matauri Bay) had better ability for the encapsulation of salicylic acid into their lumen, while patchy structure and longer tubes of patch halloysite nanotubes made the encapsulation process more difficult, as they might need more time and energy to be fully loaded by salicylic acid. Moreover, antimicrobial activity of the films against four different strains of Gram-positive and Gram-negative bacteria indicated the effective antimicrobial properties of pectin/halloysite functionalized films and their potential to be used for food packaging applications.

Encapsulation of Organic Chemicals within a Starch Matrix.

ERIC Educational Resources Information Center

Wing, R. E.; Shasha, B. S.

1983-01-01

Three experiments demonstrating the feasibility of encapsulating liquids within a starch matrix are described, including encapsulation of linseed oil using the zanthate method and of turpentine and butylate using the calcium adduct procedure. Encapsulated materials, including pesticides, are slowly released from the resulting matrix. Considers…

Antiproliferative effect of Antrodia camphorata polysaccharides encapsulated in chitosan-silica nanoparticles strongly depends on the metabolic activity type of the cell line

NASA Astrophysics Data System (ADS)

Kong, Zwe-Ling; Chang, Jenq-Sheng; Chang, Ke Liang B.

2013-09-01

Chitosan molecules interact with silica and encapsulate the Antrodia camphorata extract (ACE) polysaccharides to form composite nanoparticles. The nanoparticle suspensions of ACE polysaccharides encapsulated in silica-chitosan and silica nanoparticles approach an average particle size of 210 and 294 nm in solution, respectively. The encapsulation efficiencies of ACE polysaccharides are 66 and 63.5 %, respectively. Scanning electron micrographs confirm the formation of near-spherical nanoparticles. ACE polysaccharides solution had better antioxidative capability than ACE polysaccharides encapsulated in silica or silica-chitosan nanoparticles suspensions. The antioxidant capacity of nanoparticles increases with increasing dissolution time. The antitumor effects of ACE polysaccharides, ACE polysaccharides encapsulated in silica, or silica-chitosan nanoparticles increased with increasing concentration of nanoparticles. This is the first report demonstrating the potential of ACE polysaccharides encapsulated in chitosan-silica nanoparticles for cancer chemoprevention. Furthermore, this study suggests that antiproliferative effect of nanoparticle-encapsulated bioactive could significantly depend on the metabolic activity type of the cell line.

Stabilization of Phenylalanine Ammonia Lyase from Rhodotorula glutinis by Encapsulation in Polyethyleneimine-Mediated Biomimetic Silica.

PubMed

Cui, Jiandong; Liang, Longhao; Han, Cong; Lin Liu, Rong

2015-06-01

Phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis was encapsulated within polyethyleneimine-mediated biomimetic silica. The main factors in the preparation of biomimetic silica were optimized by response surface methodology (RSM). Compared to free PAL (about 2 U), the encapsulated PAL retained more than 43 % of their initial activity after 1 h of incubation time at 60 °C, whereas free PAL lost most of activity in the same conditions. It was clearly indicated that the thermal stability of PAL was improved by encapsulation. Moreover, the encapsulated PAL exhibited the excellent stability of the enzyme against denaturants and storage stability, and pH stability was improved by encapsulation. Operational stability of 7 reaction cycles showed that the encapsulated PAL was stable. Nevertheless, the K m value of encapsulated PAL in biomimetic silica was higher than that of the free PAL due to lower total surface area and increased mass transfer resistance.

The efficacy of methylene blue encapsulated in silica nanoparticles compared to naked methylene blue for photodynamic applications.

PubMed

Makhadmeh, Ghaseb Naser; Abdul Aziz, Azlan; Abdul Razak, Khairunisak

2016-05-01

This study analyzed the physical effects of methylene blue (MB) encapsulated within silica nanoparticles (SiNPs) in photodynamic therapy. The optimum concentration of MB needed to destroy red blood cells (RBCs) was determined, and the efficacy of encapsulated MB-SiNPs compared to that of naked MB was verified. The results confirmed the applicability of MB encapsulated in SiNPs on RBCs, and established a relationship between the concentration of the SiNP-encapsulated MB and the time required to rupture 50% of the RBCs (t50). The MB encapsulated in SiNPs exhibited higher efficacy compared to that of naked MB.

Method of making thermally removable polymeric encapsulants

DOEpatents

Small, James H.; Loy, Douglas A.; Wheeler, David R.; McElhanon, James R.; Saunders, Randall S.

2001-01-01

A method of making a thermally-removable encapsulant by heating a mixture of at least one bis(maleimide) compound and at least one monomeric tris(furan) or tetrakis(furan) compound at temperatures from above room temperature to less than approximately 90.degree. C. to form a gel and cooling the gel to form the thermally-removable encapsulant. The encapsulant can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C., preferably in a polar solvent. The encapsulant can be used in protecting electronic components that may require subsequent removal of the encapsulant for component repair, modification or quality control.

A Comparative Cytotoxic Evaluation of Disulfiram Encapsulated PLGA Nanoparticles on MCF-7 Cells.

PubMed

Fasehee, Hamidreza; Ghavamzadeh, Ardeshir; Alimoghaddam, Kamran; Ghaffari, Seyed-Hamidollah; Faghihi, Shahab

2017-04-01

Background: Disulfiram is oral aldehyde dehydrogenase (ALDH) inhibitor that has been used in the treatment of alcoholism. Recent studies show that this drug has anticancer properties; however, its rapid degradation has limited its clinical application. Encapsulation of disulfiram polymeric nanoparticles (NPs) may improve its anticancer activities and protect rapid degradation of the drug. Materials and Methods: A poly (lactide-co-Glycolide) (PLGA) was developed for encapsulation of disulfiram and its delivery into breast cancer cells. Disulfiram encapsulated PLGA NPs were prepared by nanoprecipitation method and were characterized by Scanning Electron Microscopy (SEM). The loading and encapsulation efficiency of NPs were determined using UV-Visible spectroscopy. Cell cytotoxicity of free and encapsulated form of disulfiram is also determined using MTT assay. Results: Disulfiram encapsulated PLGA NPs had uniform size with 165 nm. Drug loading and entrapment efficiency were 5.35 ±0.03% and 58.85±1.01%. The results of MTT assay showed that disulfiram encapsulated PLGA NPs were more potent in induction of apoptosis compare to free disulfiram. Conclusion: Based on the results obtained in the present study it can be concluded that encapsulation of disulfiram with PLGA can protect its degradation in improve its cytotoxicity on breast cancer cells.

Assembly of ordered carbon shells on semiconducting nanomaterials

DOEpatents

Sutter, Eli Anguelova; Sutter, Peter Werner

2010-05-11

In some embodiments of the invention, encapsulated semiconducting nanomaterials are described. In certain embodiments the nanostructures described are semiconducting nanomaterials encapsulated with ordered carbon shells. In some aspects a method for producing encapsulated semiconducting nanomaterials is disclosed. In some embodiments applications of encapsulated semiconducting nanomaterials are described.

Assembly of ordered carbon shells on semiconducting nanomaterials

DOEpatents

Sutter, Eli Anguelova; Sutter, Peter Werner

2012-10-02

In some embodiments of the invention, encapsulated semiconducting nanomaterials are described. In certain embodiments the nanostructures described are semiconducting nanomaterials encapsulated with ordered carbon shells. In some aspects a method for producing encapsulated semiconducting nanomaterials is disclosed. In some embodiments applications of encapsulated semiconducting nanomaterials are described.

Method of synthesizing and growing copper-indium-diselenide (CuInSe/sub 2/) crystals

DOEpatents

Ciszek, T.F.

1984-11-29

A process for preparing CuInSe/sub 2/ crystals includes melting a sufficient quantity of B/sub 2/O/sub 2/ along with stochiometric quantities of Cu, In, and Se in a crucible in a high-pressure atmosphere of inert gas to encapsulate the CuInSe/sub 2/ melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2% over the stochiometric quantity is preferred to make up for small amounts of Se lost in the process. The melt can then be cooled slowly to form the crystal as direct solidification, or the crystal can be grown by inserting a seed crystal through the B/sub 2/O/sub 3/ encapsulate into contact with the CuInSe/sub 2/ melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform.

PubMed

Abalde-Cela, Sara; Gould, Anna; Liu, Xin; Kazamia, Elena; Smith, Alison G; Abell, Chris

2015-05-06

Ethanol production by microorganisms is an important renewable energy source. Most processes involve fermentation of sugars from plant feedstock, but there is increasing interest in direct ethanol production by photosynthetic organisms. To facilitate this, a high-throughput screening technique for the detection of ethanol is required. Here, a method for the quantitative detection of ethanol in a microdroplet-based platform is described that can be used for screening cyanobacterial strains to identify those with the highest ethanol productivity levels. The detection of ethanol by enzymatic assay was optimized both in bulk and in microdroplets. In parallel, the encapsulation of engineered ethanol-producing cyanobacteria in microdroplets and their growth dynamics in microdroplet reservoirs were demonstrated. The combination of modular microdroplet operations including droplet generation for cyanobacteria encapsulation, droplet re-injection and pico-injection, and laser-induced fluorescence, were used to create this new platform to screen genetically engineered strains of cyanobacteria with different levels of ethanol production.

Cationic lipid-based nanoparticles mediate functional delivery of acetate to tumor cells in vivo leading to significant anticancer effects

PubMed Central

Parkinson, James R; Parkes, Harry G; So, Po Wah; Hajji, Nabil; Thomas, E Louise; Frost, Gary S

2017-01-01

Metabolic reengineering using nanoparticle delivery represents an innovative therapeutic approach to normalizing the deregulation of cellular metabolism underlying many diseases, including cancer. Here, we demonstrated a unique and novel application to the treatment of malignancy using a short-chain fatty acid (SCFA)-encapsulated lipid-based delivery system – liposome-encapsulated acetate nanoparticles for cancer applications (LITA-CAN). We assessed chronic in vivo administration of our nanoparticle in three separate murine models of colorectal cancer. We demonstrated a substantial reduction in tumor growth in the xenograft model of colorectal cancer cell lines HT-29, HCT-116 p53+/+ and HCT-116 p53−/−. Nanoparticle-induced reductions in histone deacetylase gene expression indicated a potential mechanism for these anti-proliferative effects. Together, these results indicated that LITA-CAN could be used as an effective direct or adjunct therapy to treat malignant transformation in vivo. PMID:28932113

Directing Reaction Pathways through Controlled Reactant Binding at Pd-TiO2 Interfaces.

PubMed

Zhang, Jing; Wang, Bingwen; Nikolla, Eranda; Medlin, J Will

2017-06-01

Recent efforts to design selective catalysts for multi-step reactions, such as hydrodeoxygenation (HDO), have emphasized the preparation of active sites at the interface between two materials having different properties. However, achieving precise control over interfacial properties, and thus reaction selectivity, has remained a challenge. Here, we encapsulated Pd nanoparticles (NPs) with TiO 2 films of regulated porosity to gain a new level of control over catalyst performance, resulting in essentially 100 % HDO selectivity for two biomass-derived alcohols. This catalyst also showed exceptional reaction specificity in HDO of furfural and m-cresol. In addition to improving HDO activity by maximizing the interfacial contact between the metal and metal oxide sites, encapsulation by the nanoporous oxide film provided a significant selectivity boost by restricting the accessible conformations of aromatics on the surface. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macrocyclic Receptor for Precious Gold, Platinum, or Palladium Coordination Complexes.

PubMed

Liu, Wenqi; Oliver, Allen G; Smith, Bradley D

2018-06-06

Two macrocyclic tetralactam receptors are shown to selectively encapsulate anionic, square-planar chloride and bromide coordination complexes of gold(III), platinum(II), and palladium(II). Both receptors have a preorganized structure that is complementary to its precious metal guest. The receptors do not directly ligate the guest metal center but instead provide an array of arene π-electron donors that interact with the electropositive metal and hydrogen-bond donors that interact with the outer electronegative ligands. This unique mode of supramolecular recognition is illustrated by six X-ray crystal structures showing receptor encapsulation of AuCl 4 - , AuBr 4 - , PtCl 4 -2 , or Pd 2 Cl 6 -2 . In organic solution, the 1:1 association constants correlate with specific supramolecular features identified in the solid state. Technical applications using these receptors are envisioned in a wide range of fields that involve precious metals, including mining, recycling, catalysis, nanoscience, and medicine.

Silk micrococoons for protein stabilisation and molecular encapsulation

NASA Astrophysics Data System (ADS)

Shimanovich, Ulyana; Ruggeri, Francesco S.; de Genst, Erwin; Adamcik, Jozef; Barros, Teresa P.; Porter, David; Müller, Thomas; Mezzenga, Raffaele; Dobson, Christopher M.; Vollrath, Fritz; Holland, Chris; Knowles, Tuomas P. J.

2017-07-01

Naturally spun silks generate fibres with unique properties, including strength, elasticity and biocompatibility. Here we describe a microfluidics-based strategy to spin liquid native silk, obtained directly from the silk gland of Bombyx mori silkworms, into micron-scale capsules with controllable geometry and variable levels of intermolecular β-sheet content in their protein shells. We demonstrate that such micrococoons can store internally the otherwise highly unstable liquid native silk for several months and without apparent effect on its functionality. We further demonstrate that these native silk micrococoons enable the effective encapsulation, storage and release of other aggregation-prone proteins, such as functional antibodies. These results show that native silk micrococoons are capable of preserving the full activity of sensitive cargo proteins that can aggregate and lose function under conditions of bulk storage, and thus represent an attractive class of materials for the storage and release of active biomolecules.

Synthetic mast-cell granules as adjuvants to promote and polarize immunity in lymph nodes

NASA Astrophysics Data System (ADS)

St. John, Ashley L.; Chan, Cheryl Y.; Staats, Herman F.; Leong, Kam W.; Abraham, Soman N.

2012-03-01

Granules of mast cells (MCs) enhance adaptive immunity when, on activation, they are released as stable particles. Here we show that submicrometre particles modelled after MC granules augment immunity when used as adjuvants in vaccines. The synthetic particles, which consist of a carbohydrate backbone with encapsulated inflammatory mediators such as tumour necrosis factor, replicate attributes of MCs in vivo including the targeting of draining lymph nodes and the timed release of the encapsulated mediators. When used as an adjuvant during vaccination of mice with haemagglutinin from the influenza virus, the particles enhanced adaptive immune responses and increased survival of mice on lethal challenge. Furthermore, differential loading of the particles with the cytokine IL-12 directed the character of the response towards Th1 lymphocytes. The synthetic MC adjuvants replicate and enhance the functions of MCs during vaccination, and can be extended to polarize the resulting immunity.

Noninvasive encapsulated fiber optic probes for interferometric measurement

NASA Astrophysics Data System (ADS)

Zboril, O.; Cubik, J.; Kepak, S.; Nedoma, J.; Fajkus, M.; Zavodny, P.; Vasinek, V.

2017-10-01

This article focuses on the sensitivity of encapsulated interferometric probes. These probes are used mainly for BioMed and security applications. Fiber-optic sensors are interesting for these applications, as they are resistant to electromagnetic interference (EMI) and that also do not affect the surrounding medical and security equipment. Using a loop of the optical fiber with is not a suitable for these measurements. The optical fiber should be fixed to one position, and should not significantly bend. For these reasons, the optical fiber is encapsulated. Furthermore, it is necessary that the encapsulated measuring probes were flexible, inert, water resistant and not toxic. Fiber-optic sensors shouldn't be magnetically active, so they can be used for example, in magnetic resonance environments (MR). Probes meeting these requirements can be widely used in health care and security applications. Encapsulation of interferometric measuring arm brings changes in susceptibility of measurements in comparison with the optical fiber without encapsulation. To evaluate the properties of the encapsulated probes, series of probes made from different materials for encapsulation was generated, using two types of optical fibers with various degrees of protection. Comparison of the sensitivity of different encapsulated probes was performed using a series of measurements at various frequencies. The measurement results are statistically compared in the article and commented. Given the desired properties polydimethylsiloxane (PDMS) polymer has been proven the most interesting encapsulating material for further research.

Encapsulation of alpha-amylase into starch-based biomaterials: an enzymatic approach to tailor their degradation rate.

PubMed

Azevedo, Helena S; Reis, Rui L

2009-10-01

This paper reports the effect of alpha-amylase encapsulation on the degradation rate of a starch-based biomaterial. The encapsulation method consisted in mixing a thermostable alpha-amylase with a blend of corn starch and polycaprolactone (SPCL), which were processed by compression moulding to produce circular disks. The presence of water was avoided to keep the water activity low and consequently to minimize the enzyme activity during the encapsulation process. No degradation of the starch matrix occurred during processing and storage (the encapsulated enzyme remained inactive due to the absence of water), since no significant amount of reducing sugars was detected in solution. After the encapsulation process, the released enzyme activity from the SPCL disks after 28days was found to be 40% comparatively to the free enzyme (unprocessed). Degradation studies on SPCL disks, with alpha-amylase encapsulated or free in solution, showed no significant differences on the degradation behaviour between both conditions. This indicates that alpha-amylase enzyme was successfully encapsulated with almost full retention of its enzymatic activity and the encapsulation of alpha-amylase clearly accelerates the degradation rate of the SPCL disks, when compared with the enzyme-free disks. The results obtained in this work show that degradation kinetics of the starch polymer can be controlled by the amount of encapsulated alpha-amylase into the matrix.

Microencapsulation of Drugs: New Cancer Therapies and Improved Drug Delivery Derived from Micro Gravity Research

NASA Technical Reports Server (NTRS)

Morrison, Dennis R.; Haddad, Ruwaida S.

2003-01-01

Experiments on the ISS include encapsulation of several different anti-cancer drugs, magnetic triggering particles, and encapsulation of genetically engineered DNA. Eight experiments, using the MEPS-II apparatus, were conducted to study the limitations of the fluid shear and g-dependent forces. These studies included: 1) formation of anti-tumor microcapsules containing drugs for "Chemoembolization" of vascularized tumors, 2) formation of microcapsules containing a photo-activated drug which can be used for Photo Dynamic Therapy of solid tumors by activation with near infrared light (630 nm), 3) coencapsulation of magnetic trigger particles and anti-tumor drugs, and 4) encapsulation of plasmid DNA. The Microencapsulation Electrostatic Processing System (MEPS-II) is an automated apparatus modified for use in the ISS Express Rack. The process brings together two immiscible liquids, restricting fluid shear to permitting surface tension forces to predominate at the interface of the fluids. Microcapsules were recovered from all 8 experiments and are currently being analyzed for size distribution and drug content. Six NASA Patents have issued from the space research and several more are pending. The preliminary results from the Increment 5 - UF-2 experiments have provided new insight into the best formulations and conditions required to produce microcapsules of different drugs, esp. special capsules containing diagnostic imaging materials and triggered release particles. Co-encapsulation of multiple drugs and Photodynamic Therapy (PDT) drugs has enabled new engineering strategies for production of microcapsules on Earth designed for direct delivery into cancer tissues. Other microcapsules have now been made for treatment of deep tissue infections, clotting disorders, and to provide delivery of genetic engineered materials for potential gene therapy approaches. The MEPS-II apparatus remains in the ISS awaiting microencapsulation experiments to be conducted in micro-g, and returned to Earth for analysis.

A subcutaneous cellular implant for passive immunization against amyloid-β reduces brain amyloid and tau pathologies.

PubMed

Lathuilière, Aurélien; Laversenne, Vanessa; Astolfo, Alberto; Kopetzki, Erhard; Jacobsen, Helmut; Stampanoni, Marco; Bohrmann, Bernd; Schneider, Bernard L; Aebischer, Patrick

2016-05-01

Passive immunization against misfolded toxic proteins is a promising approach to treat neurodegenerative disorders. For effective immunotherapy against Alzheimer's disease, recent clinical data indicate that monoclonal antibodies directed against the amyloid-β peptide should be administered before the onset of symptoms associated with irreversible brain damage. It is therefore critical to develop technologies for continuous antibody delivery applicable to disease prevention. Here, we addressed this question using a bioactive cellular implant to deliver recombinant anti-amyloid-β antibodies in the subcutaneous tissue. An encapsulating device permeable to macromolecules supports the long-term survival of myogenic cells over more than 10 months in immunocompetent allogeneic recipients. The encapsulated cells are genetically engineered to secrete high levels of anti-amyloid-β antibodies. Peripheral implantation leads to continuous antibody delivery to reach plasma levels that exceed 50 µg/ml. In a proof-of-concept study, we show that the recombinant antibodies produced by this system penetrate the brain and bind amyloid plaques in two mouse models of the Alzheimer's pathology. When encapsulated cells are implanted before the onset of amyloid plaque deposition in TauPS2APP mice, chronic exposure to anti-amyloid-β antibodies dramatically reduces amyloid-β40 and amyloid-β42 levels in the brain, decreases amyloid plaque burden, and most notably, prevents phospho-tau pathology in the hippocampus. These results support the use of encapsulated cell implants for passive immunotherapy against the misfolded proteins, which accumulate in Alzheimer's disease and other neurodegenerative disorders. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sustained Release of Green Tea Polyphenols from Liposomal Nanoparticles; Release Kinetics and Mathematical Modelling.

PubMed

Prakash Upputuri, Ravi Theaj; Azad Mandal, Abul Kalam

2017-01-01

Background: Green tea polyphenols (GTP) are known to have several health benefits. In spite of these benefits, its application as a therapeutic agent is limited due to some of its limitations such as stability, bioavailability, and biotransformation. To overcome these limitations, liposomal nanoparticles have been used as a carrier of the GTP. Objective: Encapsulation of GTP to the liposomal nanoparticles in order to achieve a sustained release of the GTP and to determine the drug release kinetics and the mechanism of the release. Materials and Methods: GTP encapsulated liposomal nanoparticles were prepared using phosphatidyl choline and cholesterol. The synthesized particles were characterized for their particle size and morphology. In vitro release studies were carried out, followed by drug release kinetics, and determining the mechanism of release. In vitro , antioxidant assay was determined following 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results: Atomic force microscope (AFM) and high resolution scanning electron microscope (HR SEM) images showed spherical particles of the size of 64.5 and 252 nm. An encapsulation efficiency as high as 77.7% was observed with GTP concentration of 5 mg.mL -1 . In vitro release studies showed that the loading concentrations of GTP were independent to the cumulative percentage of the drug release. GTP release by varying the pH and temperature showed a direct correlation between the release parameter and the percentage of drug release. The higher the pH and temperature, the higher was the percentage of the drug release. The release data showed a good correlation with Zero order kinetics and the mechanism of the release being anomalous mode. Radical scavenging activity of the released GTP showed a potent scavenging activity. Conclusion: GTP encapsulated liposomal nanoparticles could be used as a delivery vehicle for achieving a sustained release.

Peptide-targeted, stimuli-responsive polymersomes for delivering a cancer stemness inhibitor to cancer stem cell microtumors.

PubMed

Karandish, Fataneh; Froberg, James; Borowicz, Pawel; Wilkinson, John C; Choi, Yongki; Mallik, Sanku

2018-03-01

Often cancer relapses after an initial response to chemotherapy because of the tumor's heterogeneity and the presence of progenitor stem cells, which can renew. To overcome drug resistance, metastasis, and relapse in cancer, a promising approach is the inhibition of cancer stemness. In this study, the expression of the neuropilin-1 receptor in both pancreatic and prostate cancer stem cells was identified and targeted with a stimuli-responsive, polymeric nanocarrier to deliver a stemness inhibitor (napabucasin) to cancer stem cells. Reduction-sensitive amphiphilic block copolymers PEG 1900 -S-S-PLA 6000 and the N 3 -PEG 1900 -PLA 6000 were synthesized. The tumor penetrating iRGD peptide-hexynoic acid conjugate was linked to the N 3 -PEG 1900 -PLA 6000 polymer via a Cu 2+ catalyzed "Click" reaction. Subsequently, this peptide-polymer conjugate was incorporated into polymersomes for tumor targeting and tissue penetration. We prepared polymersomes containing 85% PEG 1900 -S-S-PLA 6000 , 10% iRGD-polymer conjugate, and 5% DPPE-lissamine rhodamine dye. The iRGD targeted polymersomes encapsulating the cancer stemness inhibitor napabucasin were internalized in both prostate and pancreatic cancer stem cells. The napabucasin encapsulated polymersomes significantly (p < .05) reduced the viability of both prostate and pancreatic cancer stem cells and decreased the stemness protein expression notch-1 and nanog compared to the control and vesicles without any drug. The napabucasin encapsulated polymersome formulations have the potential to lead to a new direction in prostate and pancreatic cancer therapy by penetrating deeply into the tumors, releasing the encapsulated stemness inhibitor, and killing cancer stem cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Liposomes for Topical Use: A Physico-Chemical Comparison of Vesicles Prepared from Egg or Soy Lecithin

PubMed Central

Budai, Lívia; Kaszás, Nóra; Gróf, Pál; Lenti, Katalin; Maghami, Katayoon; Antal, István; Klebovich, Imre; Petrikovics, Ilona; Budai, Marianna

2013-01-01

Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of these vesicular systems were investigated. The chemical composition of the two types of lecithin was checked by mass spectrometry. Caffeine, as a model molecule, was encapsulated into multilamellar vesicles prepared from the two types of lecithin: then zeta potential, membrane fluidity, and encapsulation efficiency were compared. According to our observations, samples prepared from the two lecithins altered the pH in opposite directions: egg lecithin increased it while soy lecithin decreased it with increased lipid concentration. Our EPR spectroscopic results showed that the binding of caffeine did not change the membrane fluidity in the temperature range of possible topical use (measured between 2 and 50 °C). Combining our results on encapsulation efficiency for caffeine (about 30% for both lecithins) with those on membrane fluidity data, we concluded that the interaction of caffeine with the liposomal membrane does not change the rotational motion of the lipid molecules close to the head group region. In conclusion, topical use of egg lecithin for liposomal formulations can be preferred if there are no differences in the physico-chemical properties due to the encapsulated drugs, because the physiological effects of egg lecithin vesicles on skin are significantly better than that of soy lecithin liposomes. PMID:24482779

Immunogenicity of diphtheria toxoid and poly(I:C) loaded cationic liposomes after hollow microneedle-mediated intradermal injection in mice.

PubMed

Du, Guangsheng; Leone, Mara; Romeijn, Stefan; Kersten, Gideon; Jiskoot, Wim; Bouwstra, Joke A

2018-06-02

In this study, we aimed to investigate the immunogenicity of cationic liposomes loaded with diphtheria toxoid (DT) and poly(I:C) after hollow microneedle-mediated intradermal vaccination in mice. The following liposomal formulations were studied: DT loaded liposomes, a mixture of free DT and poly(I:C)-loaded liposomes, a mixture of DT-loaded liposomes and free poly(I:C), and liposomal formulations with DT and poly(I:C) either individually or co-encapsulated in the liposomes. Reference groups were DT solution adjuvanted with or without poly(I:C) (DT/poly(I:C)). The liposomal formulations were characterized in terms of particle size, zeta potential, loading and release of DT and poly(I:C). After intradermal injection of BALB/c mice with the formulations through a hollow microneedle, the immunogenicity was assessed by DT-specific ELISAs. All formulations induced similar total IgG and IgG1 titers. However, all the liposomal groups containing both DT and poly(I:C) showed enhanced IgG2a titers compared to DT/poly(I:C) solution, indicating that the immune response was skewed towards a Th1 direction. This enhancement was similar for all liposomal groups that contain both DT and poly(I:C) in the formulations. Our results reveal that a mixture of DT encapsulated liposomes and poly(I:C) encapsulated liposomes have a similar effect on the antibody responses as DT and poly(I:C) co-encapsulated liposomes. These findings may have implications for future design of liposomal vaccine delivery systems. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Use of acidifiers and herb-acidifier combinations with encapsulated and non-encapsulated intestinal microflora, intestinal histological and serum characteristics in broiler

NASA Astrophysics Data System (ADS)

Natsir, Muhammad Halim; Hartutik, Sjofjan, Osfar; Widodo, Eko; Widyastuti, Eny Sri

2017-05-01

The objective of this experiment was to evaluate the use of acidifier and herb-acidifier combinations on intestinal microflora, intestinal histology and serum characteristics of broilers at 35 days of age when fed a diet supplemented with natural acidifier (lactic acid and citric acid), and herb-acidifier combinations (natural acidifier and herbs (garlic and Phyllanthus niruri L.) encapsulated and non-encapsulated. Here, 192 (Lohmann) broiler chicks were fed a negative control diet, positive control diet (tetracycline), 1.2% acidifier non-encapsulated (ANE), 1.2% acidifier encapsulated (AE), 1.2% herb-acidifier combination non-encapsulated (CNE), or 1.2% herb-acidifier combination encapsulated (CE). The variables measured were the total colony of lactic acid bacteria, Escherichia coli and Salmonella sp., intestinal histological characteristics (crypt depth, villi number, villi length, and viscosity) and serum (total protein, serum albumin, and serum globulin). Results showed that during the 35-d growth period, there were significant differences (P<0.01) in increases of the total number of colonies of lactic acid bacteria and a decrease in the total colony of Escherichia coli and Salmonella sp., along with increasing intestinal histological characteristics (crypt depth, villi number, villi length, and viscosity) and total proteins in the serum, as well as significant effects (P<0.05) on intestinal pH and serum albumin. It is concluded that the use acidifiers or herb-acidifier combinations in encapsulation performed better than without encapsulation. Therefore using 1.2% of encapsulated combinations of herb-acidifiers in broiler diet is recommended.

Partially chaotic orbits in a perturbed cubic force model

NASA Astrophysics Data System (ADS)

Muzzio, J. C.

2017-11-01

Three types of orbits are theoretically possible in autonomous Hamiltonian systems with 3 degrees of freedom: fully chaotic (they only obey the energy integral), partially chaotic (they obey an additional isolating integral besides energy) and regular (they obey two isolating integrals besides energy). The existence of partially chaotic orbits has been denied by several authors, however, arguing either that there is a sudden transition from regularity to full chaoticity or that a long enough follow-up of a supposedly partially chaotic orbit would reveal a fully chaotic nature. This situation needs clarification, because partially chaotic orbits might play a significant role in the process of chaotic diffusion. Here we use numerically computed Lyapunov exponents to explore the phase space of a perturbed three-dimensional cubic force toy model, and a generalization of the Poincaré maps to show that partially chaotic orbits are actually present in that model. They turn out to be double orbits joined by a bifurcation zone, which is the most likely source of their chaos, and they are encapsulated in regions of phase space bounded by regular orbits similar to each one of the components of the double orbit.

Understanding Unimer Exchange Processes in Block Copolymer Micelles using NMR Diffusometry, Time-Resolved NMR, and SANS

NASA Astrophysics Data System (ADS)

Madsen, Louis; Kidd, Bryce; Li, Xiuli; Miller, Katherine; Cooksey, Tyler; Robertson, Megan

Our team seeks to understand dynamic behaviors of block copolymer micelles and their interplay with encapsulated cargo molecules. Quantifying unimer and cargo exchange rates micelles can provide critical information for determining mechanisms of unimer exchange as well as designing systems for specific cargo release dynamics. We are exploring the utility of NMR spectroscopy and diffusometry techniques as complements to existing SANS and fluorescence methods. One promising new method involves time-resolved NMR spin relaxation measurements, wherein mixing of fully protonated and 2H-labeled PEO-b-PCL micelles solutions shows an increase in spin-lattice relaxation time (T1) with time after mixing. This is due to a weakening in magnetic environment surrounding 1H spins as 2H-bearing unimers join fully protonated micelles. We are measuring time constants for unimer exchange of minutes to hours, and we expect to resolve times of <1 min. This method can work on any solution NMR spectrometer and with minimal perturbation to chemical structure (as in dye-labelled fluorescence methods). Multimodal NMR can complement existing characterization tools, expanding and accelerating dynamics measurements for polymer micelle, nanogel, and nanoparticle developers.

Neutronics Studies of Uranium-bearing Fully Ceramic Micro-encapsulated Fuel for PWRs

DOE PAGES

George, Nathan M.; Maldonado, G. Ivan; Terrani, Kurt A.; ...

2014-12-01

Our study evaluated the neutronics and some of the fuel cycle characteristics of using uranium-based fully ceramic microencapsulated (FCM) fuel in a pressurized water reactor (PWR). Specific PWR lattice designs with FCM fuel have been developed that are expected to achieve higher specific burnup levels in the fuel while also increasing the tolerance to reactor accidents. The SCALE software system was the primary analysis tool used to model the lattice designs. A parametric study was performed by varying tristructural isotropic particle design features (e.g., kernel diameter, coating layer thicknesses, and packing fraction) to understand the impact on reactivity and resultingmore » operating cycle length. Moreover, to match the lifetime of an 18-month PWR cycle, the FCM particle fuel design required roughly 10% additional fissile material at beginning of life compared with that of a standard uranium dioxide (UO 2) rod. Uranium mononitride proved to be a favorable fuel for the fuel kernel due to its higher heavy metal loading density compared with UO 2. The FCM fuel designs evaluated maintain acceptable neutronics design features for fuel lifetime, lattice peaking factors, and nonproliferation figure of merit.« less

A Fully Implantable Stimulator With Wireless Power and Data Transmission for Experimental Investigation of Epidural Spinal Cord Stimulation.

PubMed

Xu, Qi; Hu, Dingyin; Duan, Bingyu; He, Jiping

2015-07-01

Epidural spinal cord stimulation (ESCS) combined with partial weight-bearing therapy (PWBT) has been shown to facilitate recovery of functional walking for individuals after spinal cord injury (SCI). The investigation of neural mechanisms of recovery from SCI under this treatment has been conducted broadly in rodent models, yet a suitable ESCS system is still unavailable. This paper describes a practical, programmable, and fully implantable stimulator for laboratory research on rats to explore fundamental neurophysiological principles for functional recovery after SCI. The ESCS system is composed of a personal digital assistant (PDA), an external controller, an implantable pulse generator (IPG), lead extension, and stimulating electrodes. The stimulation parameters can be programmed and adjusted through a graphical user interface on the PDA. The external controller is placed on the rat back and communicates with the PDA via radio-frequency (RF) telemetry. An RF carrier from the class-E power amplifier in the external controller provides both data and power for the IPG through an inductive link. The IPG is built around a microcontroller unit to generate voltage-regulated pulses delivered to the bipolar electrode for ESCS in rats. The encapsulated IPG measures 22 mm × 23 mm × 7 mm with a mass of  ∼  3.78 g. This fully implantable batteryless stimulator provided a simplified and efficient method to carry out chronic experiments in untethered animals for medical electro-neurological research.

Novel chitosan film embedded with liposome-encapsulated phage for biocontrol of Escherichia coli O157:H7 in beef.

PubMed

Cui, Haiying; Yuan, Lu; Lin, Lin

2017-12-01

In recent years, phages used for the reduction of pathogenic bacteria have fostered many attentions, but they are liable to lost bioactivity in food due to the presence of acidic compounds, enzymes and evaporite materials. To improve the stability of phages, a chitosan edible film containing liposome-encapsulated phage was engineered in the present study. The characteristics of liposome-encapsulated phage and the chitosan film containing liposome-encapsulated phage were investigated. The encapsulation efficiency of phages in liposome reached 57.66±0.12%. Besides, the desirable physical properties of chitosan film were obtained. The chitosan film embedded with liposome-encapsulated phage exhibited high antibacterial activity against Escherichia coli O157:H7, without the impact on the sensory properties of beef. Hence, chitosan film containing liposome-encapsulated phage could be a promising antibacterial packaging for beef preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization and Antilisterial Effect of Phosphatidylcholine Nanovesicles Containing the Antimicrobial Peptide Pediocin.

PubMed

de Mello, Michele Brauner; da Silva Malheiros, Patrícia; Brandelli, Adriano; Pesce da Silveira, Nádya; Jantzen, Márcia Monks; de Souza da Motta, Amanda

2013-03-01

Encapsulation may provide increased stability and antimicrobial efficiency to bacteriocins. In this work, the antilisterial peptide pediocin was encapsulated in nanovesicles prepared from partially purified soybean phosphatidylcholine. The maintenance of antimicrobial activity and properties of free and encapsulated pediocin was observed during 13 days at 4 °C, and after this period, the encapsulated pediocin retained 50 % its initial activity. The maintenance of the bioactive properties of free and encapsulated pediocin was observed against different species of Listeria, inhibiting Listeria monocytogenes, Listeria innocua and Listeria ivanovii. The size of vesicles containing pediocin was determined by dynamic light scattering as an average of 190 nm, with little change throughout the observation period. Polydispersity index values were around 0.201 and are considered satisfactory, indicating an adequate size distribution of liposomes. The efficiency of encapsulation was 80 %. Considering these results, the protocol used was appropriate for the encapsulation of this bacteriocin. Results demonstrate the production of stable nanoparticulate material. The maintenance of the properties of pediocin encapsulated in liposomes is fundamental to prospect the stability in different conditions of the food matrix.

Light emitting diode package element with internal meniscus for bubble free lens placement

DOEpatents

Tarsa, Eric; Yuan, Thomas C.; Becerra, Maryanne; Yadev, Praveen

2010-09-28

A method for fabricating a light emitting diode (LED) package comprising providing an LED chip and covering at least part of the LED chip with a liquid encapsulant having a radius of curvature. An optical element is provided having a bottom surface with at least a portion having a radius of curvature larger than the liquid encapsulant. The larger radius of curvature portion of the optical element is brought into contact with the liquid encapsulant. The optical element is then moved closer to the LED chip, growing the contact area between said optical element and said liquid encapsulant. The liquid encapsulant is then cured. A light emitting diode comprising a substrate with an LED chip mounted to it. A meniscus ring is on the substrate around the LED chip with the meniscus ring having a meniscus holding feature. An inner encapsulant is provided over the LED chip with the inner encapsulant having a contacting surface on the substrate, with the meniscus holding feature which defines the edge of the contacting surface. An optical element is included having a bottom surface with at least a portion that is concave. The optical element is arranged on the substrate with the concave portion over the LED chip. A contacting encapsulant is included between the inner encapsulant and optical element.

A Comparative Cytotoxic Evaluation of Disulfiram Encapsulated PLGA Nanoparticles on MCF-7 Cells

PubMed Central

Fasehee, Hamidreza; Ghavamzadeh, Ardeshir; Alimoghaddam, Kamran; Ghaffari, Seyed-Hamidollah; Faghihi, Shahab

2017-01-01

Background: Disulfiram is oral aldehyde dehydrogenase (ALDH) inhibitor that has been used in the treatment of alcoholism. Recent studies show that this drug has anticancer properties; however, its rapid degradation has limited its clinical application. Encapsulation of disulfiram polymeric nanoparticles (NPs) may improve its anticancer activities and protect rapid degradation of the drug. Materials and Methods: A poly (lactide-co-Glycolide) (PLGA) was developed for encapsulation of disulfiram and its delivery into breast cancer cells. Disulfiram encapsulated PLGA NPs were prepared by nanoprecipitation method and were characterized by Scanning Electron Microscopy (SEM). The loading and encapsulation efficiency of NPs were determined using UV-Visible spectroscopy. Cell cytotoxicity of free and encapsulated form of disulfiram is also determined using MTT assay. Results: Disulfiram encapsulated PLGA NPs had uniform size with 165 nm. Drug loading and entrapment efficiency were 5.35 ±0.03% and 58.85±1.01%. The results of MTT assay showed that disulfiram encapsulated PLGA NPs were more potent in induction of apoptosis compare to free disulfiram. Conclusion: Based on the results obtained in the present study it can be concluded that encapsulation of disulfiram with PLGA can protect its degradation in improve its cytotoxicity on breast cancer cells. PMID:28875004

Laboratory evaluation of polychlorinated biphenyls ...

EPA Pesticide Factsheets

Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, and petroleum-based paint were tested in small environmental chambers to rank the encapsulants by their resistance to PCB sorption and estimate the key parameters required by a barrier model. Wipe samples were collected from PCB contaminated surface encapsulated with the coating materials to rank the encapsulants by their resistance to PCB migration from the source. A barrier model was used to calculate the PCB concentrations in the sources and the encapsulant layers, and at the exposed surfaces of the encapsulant and in the room air at different times. The performance of the encapsulants was ranked by those concentrations and PCB percent reductions. Overall, the three epoxy coatings performed better than the other coatings. Both the experimental results and the mathematical modeling showed that selecting proper encapsulants can effectively reduce the PCB concentrations at the exposed surfaces. The encapsulation method is most effective for contaminated surfaces that contain low levels of PCBs. This study answers some of these questions by using a combination of laboratory testing and mathematical modeling. The results should be useful to mitigation engineers, building owners and managers

Biological responses of T cells encapsulated with polyelectrolyte-coated gold nanorods and their cellular activities in a co-culture system

NASA Astrophysics Data System (ADS)

Wattanakull, Porntida; Killingsworth, Murray C.; Pissuwan, Dakrong

2017-11-01

Currently, human T cell therapy is of considerable scientific interest. In addition, cell encapsulation has become an attractive approach in biomedical applications. Here, we propose an innovative technique of single-cell encapsulation of human T cells using polyelectrolytes combined with gold nanorods. We have demonstrated encapsulation of human Jurkat T cells with poly(sodium 4-styrenesulfonate) (PSS)-coated gold nanorods (PSS-GNRs). Other forms of encapsulation, using polyelectrolytes without GNRs, were also performed. After Jurkat T cells were encapsulated with poly(allylamine hydrochloride) (PAH) and/or PSS-GNRs or PSS, most cells survived and could proliferate. Jurkat T cells encapsulated with a double layer of PSS-GNR/PAH (PSS-GNR/PAH@Jurkat) showed the highest rate of cell proliferation when compared to 24-h encapsulated cells. With the exception of IL-6, no significant induction of inflammatory cytokines (IL-2, IL-1β, and TNF-α) was observed. Interestingly, when encapsulated cells were co-cultured with THP-1 macrophages, co-cultures exhibited TNF-α production enhancement. However, the co-culture of THP-1 macrophage and PSS-GNR/PAH@Jurkat or PSS/PAH@Jurkat did not enhance TNF-α production. No significant inductions of IL-2, IL-1β, and IL-6 were detected. These data provide promising results, demonstrating the potential use of encapsulated PSS-GNR/PAH@Jurkat to provide a more inert T cell population for immunotherapy application and other biomedical applications.

Preserving viability of Lactobacillus rhamnosus GG in vitro and in vivo by a new encapsulation system

PubMed Central

Li, Ran; Zhang, Yufeng; Polk, D. Brent; Tomasula, Peggy M.; Yan, Fang; Liu, LinShu

2016-01-01

Probiotics have shown beneficial effects on health and prevention of diseases in humans. However, a concern for application of probiotics is the loss of viability during storage and gastrointestinal transit. The aim of this study was to develop an encapsulation system to preserve viability of probiotics when they are administrated orally and apply Lactobacillus rhamnosus GG (LGG) as a probiotic model to evaluate the effectiveness of this approach using in vitro and in vivo experiments. LGG was encapsulated in hydrogel beads prepared using pectin, a food grade polysaccharide, glucose, and calcium chloride, and lyophilized by freeze-drying. Encapsulated LGG was cultured in vitro under the condition that mimicked the physiological environment of the human gastrointestinal tract. Compared to non-encapsulated LGG, encapsulation increased tolerance of LGG in the acid condition, protected LGG from protease digestion, and improved shelf time when stored at the ambient condition, in regard of survivability and production of p40, a known LGG-derived protein involved in LGG’s beneficial effects on intestinal homeostasis. To evaluate the effects of encapsulation on p40 production in vivo and prevention of intestinal inflammation by LGG, mice were gavaged with LGG containing beads and treated with dextran sulphate sodium (DSS) to induce intestinal injury and colitis. Compared to non-encapsulated LGG, encapsulated LGG enhanced more p40 production in mice, and exerted higher levels of effects on prevention of DSS-induced colonic injury and colitis and suppression of pro-inflammatory cytokine production. These data indicated that the encapsulation system developed in this study preserves viability of LGG in vitro and in vivo, leading to longer shelf time and enhancing the functions of LGG in the gastrointestinal tract. Thus, this encapsulation approach may have the potential application for improving efficacy of probiotics. PMID:27063422

Germination and Seedling Growth of Perennial Ryegrass in Acid Sulfate Soil Treated by Pyrite Nano-Encapsulation

NASA Astrophysics Data System (ADS)

Lee, J.; Kim, J.; Yi, J.; Kim, T.

2007-05-01

The trial pot experiment was conducted to validate the effect of encapsulation in reduction of acid rock drainage. Six different treatments were performed: A = control, four times spraying of distilled water; B = four times of 0.01 M H2O2; C = once-encapsulated and three times spraying of distilled water; D = twice-encapsulated and twice spraying of distilled water; E = three times-encapsulated and once spraying of distilled water and F = four times-encapsulated for the acid sulfate soil with pyrite bearing andesite powder and sand. After the encapsulation treatment, the perennial ryegrass (Loium perenne) was sowed to evaluate germination rate and growth for three months. The leachate was examined for the chemical properties. The leachate from the A pot (control) is characterized as acidic (pH below 3) and high concentrations of SO4-2: 12,022 mg/L, Al: 85.8 mg/L and Mn: 34.1 mg/L which can be toxic effect to the plant growth. However, the leachate from encapsulated pots showed near neutral (pH 6 to 7) and low concentrations of SO4-2 (below 3,000 mg/L), Al (below 45mg/L) and Mn (24 gm/L). The frequency of encapsulation treatment is related to reduction of acidic drainage. It was hard to identify the significant difference of the seed germination rate of ryegrass between the treatments, although root and shoot growth showed three times difference between the control (1.90g/pot) and four times encapsulated treatment (6.33g/pot) after 2 month growth. It is suggested that encapsulation of pyrite in acid sulfate soil causes the reduction of acidic drainage resulting in the higher growth of herbaceous plants.

Characterization Methods of Encapsulates

NASA Astrophysics Data System (ADS)

Zhang, Zhibing; Law, Daniel; Lian, Guoping

Food active ingredients can be encapsulated by different processes, including spray drying, spray cooling, spray chilling, spinning disc and centrifugal co-extrusion, extrusion, fluidized bed coating and coacervation (see Chap. 2 of this book). The purpose of encapsulation is often to stabilize an active ingredient, control its release rate and/or convert a liquid formulation into a solid which is easier to handle. A range of edible materials can be used as shell materials of encapsulates, including polysaccharides, fats, waxes and proteins (see Chap. 3 of this book). Encapsulates for typical industrial applications can vary from several microns to several millimetres in diameter although there is an increasing interest in preparing nano-encapsulates. Encapsulates are basically particles with a core-shell structure, but some of them can have a more complex structure, e.g. in a form of multiple cores embedded in a matrix. Particles have physical, mechanical and structural properties, including particle size, size distribution, morphology, surface charge, wall thickness, mechanical strength, glass transition temperature, degree of crystallinity, flowability and permeability. Information about the properties of encapsulates is very important to understanding their behaviours in different environments, including their manufacturing processes and end-user applications. E.g. encapsulates for most industrial applications should have desirable mechanical strength, which should be strong enough to withstand various mechanical forces generated in manufacturing processes, such as mixing, pumping, extrusion, etc., and may be required to be weak enough in order to release the encapsulated active ingredients by mechanical forces at their end-user applications, such as release rate of flavour by chewing. The mechanical strength of encapsulates and release rate of their food actives are related to their size, morphology, wall thickness, chemical composition, structure etc. Hence, reliable methods which can be used to characterize these properties of encapsulates are vital. In this chapter, the state-of-art of these methods, their principles and applications, and release mechanisms are described as follows.

Cellular Encapsulation Enhances Cardiac Repair

PubMed Central

Levit, Rebecca D.; Landázuri, Natalia; Phelps, Edward A.; Brown, Milton E.; García, Andrés J.; Davis, Michael E.; Joseph, Giji; Long, Robert; Safley, Susan A.; Suever, Jonathan D.; Lyle, Alicia N.; Weber, Collin J.; Taylor, W. Robert

2013-01-01

Background Stem cells for cardiac repair have shown promise in preclinical trials, but lower than expected retention, viability, and efficacy. Encapsulation is one potential strategy to increase viable cell retention while facilitating paracrine effects. Methods and Results Human mesenchymal stem cells (hMSC) were encapsulated in alginate and attached to the heart with a hydrogel patch in a rat myocardial infarction (MI) model. Cells were tracked using bioluminescence (BLI) and cardiac function measured by transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR). Microvasculature was quantified using von Willebrand factor staining and scar measured by Masson's Trichrome. Post‐MI ejection fraction by CMR was greatly improved in encapsulated hMSC‐treated animals (MI: 34±3%, MI+Gel: 35±3%, MI+Gel+hMSC: 39±2%, MI+Gel+encapsulated hMSC: 56±1%; n=4 per group; P<0.01). Data represent mean±SEM. By TTE, encapsulated hMSC‐treated animals had improved fractional shortening. Longitudinal BLI showed greatest hMSC retention when the cells were encapsulated (P<0.05). Scar size at 28 days was significantly reduced in encapsulated hMSC‐treated animals (MI: 12±1%, n=8; MI+Gel: 14±2%, n=7; MI+Gel+hMSC: 14±1%, n=7; MI+Gel+encapsulated hMSC: 7±1%, n=6; P<0.05). There was a large increase in microvascular density in the peri‐infarct area (MI: 121±10, n=7; MI+Gel: 153±26, n=5; MI+Gel+hMSC: 198±18, n=7; MI+Gel+encapsulated hMSC: 828±56 vessels/mm2, n=6; P<0.01). Conclusions Alginate encapsulation improved retention of hMSCs and facilitated paracrine effects such as increased peri‐infarct microvasculature and decreased scar. Encapsulation of MSCs improved cardiac function post‐MI and represents a new, translatable strategy for optimization of regenerative therapies for cardiovascular diseases. PMID:24113327

Liposome-encapsulated actinomycin for cancer chemotherapy

DOEpatents

Rahman, Yueh-Erh; Cerny, Elizabeth A.

1976-01-01

An improved method is provided for chemotherapy of malignant tumors by injection of antitumor drugs. The antitumor drug is encapsulated within liposomes and the liposomes containing the encapsulated drug are injected into the body. The encapsulated drug penetrates into the tumor cells where the drug is slowly released and induces degeneration and death of the tumor cells, while any toxicity to the host body is reduced. Liposome encapsulation of actinomycin D has been found to be particularly effective in treating cancerous abdominal tumors, while drastically reducing the toxicity of actinomycin D to the host.

Studies of encapsulant materials for terrestrial solar-cell arrays

NASA Technical Reports Server (NTRS)

Carmichael, D. C. (Compiler)

1975-01-01

Study 1 of this contract is entitled ""Evaluation of World Experience and Properties of Materials for Encapsulation of Terrestrial Solar-Cell Arrays.'' The approach of this study is to review and analyze world experience and to compile data on properties of encapsulants for photovoltaic cells and for related applications. The objective of the effort is to recommend candidate materials and processes for encapsulating terrestrial photovoltaic arrays at low cost for a service life greater than 20 years. The objectives of Study 2, ""Definition of Encapsulant Service Environments and Test Conditions,'' are to develop the climatic/environmental data required to define the frequency and duration of detrimental environmental conditions in a 20-year array lifetime and to develop a corresponding test schedule for encapsulant systems.

Fluid replacement advice during work in fully encapsulated impermeable chemical protective suits.

PubMed

Rubenstein, Candace D; DenHartog, Emiel A; Deaton, A Shawn; Bogerd, Cornelis P; DeKant, Saskia

2017-06-01

A major concern for responders to hazardous materials (HazMat) incidents is the heat strain that is caused by fully encapsulated impermeable chemical protective suits. In a research project, funded by the US Department of Defense, the thermal strain experienced when wearing these suits was studied. One particular area of interest was the fluid loss of responders during work in these suits as dehydration may be an additional health concern to the heat strain. 17 City of Raleigh firemen and 24 students were tested at two different labs. Subjects between the ages of 25 and 51 were used for human subject trials in a protocol approved by the local ethical committee. Six different Level A HazMat suits were evaluated in three climates: moderate (24°C, 50% RH, 20°C WBGT), warm-wet (32°C, 60% RH, 30°C WBGT), and hot-dry (45°C, 20% RH, 37°C WBGT, 200 W/m 2 radiant load) and at three walking speeds: 2.5 km/hr, 4 km/hr, and 5.5 km/hr. 4 km/hr was tested in all three climates and the other two walking speeds were tested in the moderate climate. Weight loss data was collected to determine fluid loss during these experiments. Working time ranged from as low as 20 min in the hot-dry condition to 60 min (the maximum) in the moderate climate, especially common at the lowest walking speed. The overall results from all experiments showed that fluid loss ranged from 0.2-2.2 L during these exposures, with the average fluid loss being 0.8 L, with 56% of the data between 0.5 L and 1 L of fluid loss. Further analysis showed that a suggestion of drinking 0.7 Liter per hour would safely hydrate over 50% of responders after one work-rest cycle. Applying this fluid volume over three work-rest cycles only put 11% of responders at risk of hypohydration vs. the 57% at risk with no fluid intake.

Aerosol delivery of liposome-encapsulated ciprofloxacin: aerosol characterization and efficacy against Francisella tularensis infection in mice.

PubMed

Conley, J; Yang, H; Wilson, T; Blasetti, K; Di Ninno, V; Schnell, G; Wong, J P

1997-06-01

The aerosol delivery of liposome-encapsulated ciprofloxacin by using 12 commercially available jet nebulizers was evaluated in this study. Aerosol particles containing liposome-encapsulated ciprofloxacin generated by the nebulizers were analyzed with a laser aerodynamic particle sizer. Mean mass aerodynamic diameters (MMADs) and geometric standard deviations (GSDs) were determined, and the drug contents of the sampling filters from each run onto which aerosolized liposome-encapsulated ciprofloxacin had been deposited were analyzed spectrophotometrically. The aerosol particles of liposome-encapsulated ciprofloxacin generated by these nebulizers ranged from 1.94 to 3.5 microm, with GSDs ranging from 1.51 to 1.84 microm. The drug contents of the sampling filters exposed for 1 min to aerosolized liposome-encapsulated ciprofloxacin range from 12.7 to 40.5 microg/ml (0.06 to 0.2 mg/filter). By using the nebulizer selected on the basis of most desirable MMADs, particle counts, and drug deposition, aerosolized liposome-encapsulated ciprofloxacin was used for the treatment of mice infected with 10 times the 50% lethal dose of Francisella tularensis. All mice treated with aerosolized liposome-encapsulated ciprofloxacin survived the infection, while all ciprofloxacin-treated or untreated control mice succumbed to the infection (P < 0.001). These results suggest that aerosol delivery of liposome-encapsulated ciprofloxacin to the lower respiratory tract is feasible and that it may provide an effective therapy for the treatment of respiratory tract infections.

[Influence of wall polymer and preparation process on the particle size and encapsulation of hemoglobin microcapsules].

PubMed

Qiu, Wei; Ma, Guang-Hui; Meng, Fan-Tao; Su, Zhi-Guo

2004-03-01

Methoxypoly (ethylene glycol)- block-poly (DL-lactide) (PELA) microcapsules containing bovine hemoglobin (BHb) were prepared by a W/O/W double emulsion-solvent diffusion process. The P50 and Hill coeffcient were 3466 Pa and 2.4 respectively, which were near to the natural bioactivity of bovine hemoglobin. The results suggested that polymer composition had significant influence on encapsulation efficiency and particle size of microcapsules. The encapsulation efficiency could reach 90% and the particle size 3 - 5 microm when the PELA copolymer containing MPEG 2000 block was used. The encapsulation efficiency and particle size increased with the concentration of PELA. Increasing the concentrations of NaCl in outer aqueous solution resulted in the increase of encapsulation efficiency and the decrease of particle size. As the concentration of stabilizer in outer aqueous solution increased in the range of 10 g/L to 20 g/L, the particle size reduced while encapsulation efficiency was increased, further increase of the stabilizer concentration would decrease encapsulation efficiency. Increasing of primary emulsion stirring rate was advantageous to the improvement of encapsulation efficiency though it had little influence on the particle size. The influence of re-emulsion stirring rate was complicated, which was not apparent in the case of large volume of re-emulsion solution. When the wall polymer and primary emulsion stirring rate were fixed, the encapsulation efficiency decreased as the particle size reduced.

Direct writing of metal nanostructures: lithographic tools for nanoplasmonics research.

PubMed

Leggett, Graham J

2011-03-22

Continued progress in the fast-growing field of nanoplasmonics will require the development of new methods for the fabrication of metal nanostructures. Optical lithography provides a continually expanding tool box. Two-photon processes, as demonstrated by Shukla et al. (doi: 10.1021/nn103015g), enable the fabrication of gold nanostructures encapsulated in dielectric material in a simple, direct process and offer the prospect of three-dimensional fabrication. At higher resolution, scanning probe techniques enable nanoparticle particle placement by localized oxidation, and near-field sintering of nanoparticulate films enables direct writing of nanowires. Direct laser "printing" of single gold nanoparticles offers a remarkable capability for the controlled fabrication of model structures for fundamental studies, particle-by-particle. Optical methods continue to provide a powerful support for research into metamaterials.

Hermetic Encapsulation of Nanoenergetic Porous Silicon Wafer by Parylene

DTIC Science & Technology

2014-08-01

Hermetic Encapsulation of Nanoenergetic Porous Silicon Wafer by Parylene by Eugene Zakar, Wayne Churaman, Collin Becker, Bernard Rod, Luke...Laboratory Adelphi, MD 20783-1138 ARL-TR-7025 August 2014 Hermetic Encapsulation of Nanoenergetic Porous Silicon Wafer by Parylene...Hermetic Encapsulation of Nanoenergetic Porous Silicon Wafer by Parylene 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Elevating bioavailability of curcumin via encapsulation with a novel formulation of artificial oil bodies.

PubMed

Chang, Ming-Tsung; Tsai, Tong-Rong; Lee, Chun-Yann; Wei, Yu-Sheng; Chen, Ying-Jie; Chen, Chun-Ren; Tzen, Jason T C

2013-10-09

Utilization of curcumin has been limited due to its poor oral bioavailability. Oral bioavailability of hydrophobic compounds might be elevated via encapsulation in artificial seed oil bodies. This study aimed to improve oral bioavailability of curcumin via this encapsulation. Unfortunately, curcumin was indissoluble in various seed oils. A mixed dissolvent formula was used to dissolve curcumin, and the admixture was successfully encapsulated in artificial oil bodies stabilized by recombinant sesame caleosin. The artificial oil bodies of relatively small sizes (150 nm) were stably solidified in the forms of powder and tablet. Oral bioavailability of curcumin with or without encapsulation in artificial oil bodies was assessed in Sprague-Dawley male rats. The results showed that encapsulation of curcumin significantly elevated its bioavailability and provided the highest maximum whole blood concentration (Cmax), 37 ± 28 ng/mL, in the experimental animals 45 ± 17 min (t(max)) after oral administration. Relative bioavailability calculated on the basis of the area under the plasma concentration-time curve (AUC) was increased by 47.7 times when curcumin was encapsulated in the artificial oil bodies. This novel formulation of artificial oil bodies seems to possess great potential to encapsulate hydrophobic drugs for oral administration.

Comparative studies on osmosis based encapsulation of sodium diclofenac in porcine and outdated human erythrocyte ghosts.

PubMed

Bukara, Katarina; Drvenica, Ivana; Ilić, Vesna; Stančić, Ana; Mišić, Danijela; Vasić, Borislav; Gajić, Radoš; Vučetić, Dušan; Kiekens, Filip; Bugarski, Branko

2016-12-20

The objective of our study was to develop controlled drug delivery system based on erythrocyte ghosts for amphiphilic compound sodium diclofenac considering the differences between erythrocytes derived from two readily available materials - porcine slaughterhouse and outdated transfusion human blood. Starting erythrocytes, empty erythrocyte ghosts and diclofenac loaded ghosts were compared in terms of the encapsulation efficiency, drug releasing profiles, size distribution, surface charge, conductivity, surface roughness and morphology. The encapsulation of sodium diclofenac was performed by an osmosis based process - gradual hemolysis. During this process sodium diclofenac exerted mild and delayed antihemolytic effect and increased potassium efflux in porcine but not in outdated human erythrocytes. FTIR spectra revealed lack of any membrane lipid disorder and chemical reaction with sodium diclofenac in encapsulated ghosts. Outdated human erythrocyte ghosts with detected nanoscale damages and reduced ability to shrink had encapsulation efficiency of only 8%. On the other hand, porcine erythrocyte ghosts had encapsulation efficiency of 37% and relatively slow drug release rate. More preserved structure and functional properties of porcine erythrocytes related to their superior encapsulation and release performances, define them as more appropriate for the usage in sodium diclofenac encapsulation process. Copyright © 2016 Elsevier B.V. All rights reserved.

Encapsulated Unresolved Subdural Hematoma Mimicking Acute Epidural Hematoma: A Case Report

PubMed Central

Park, Sang-Soo; Kim, Hyo-Joon; Kwon, Chang-Young

2014-01-01

Encapsulated acute subdural hematoma (ASDH) has been uncommonly reported. To our knowledge, a few cases of lentiform ASDH have been reported. The mechanism of encapsulated ASDH has been studied but not completely clarified. Encapsulated lentiform ASDH on a computed tomography (CT) scan mimics acute epidural hematoma (AEDH). Misinterpretation of biconvex-shaped ASDH on CT scan as AEDH often occurs and is usually identified by neurosurgical intervention. We report a case of an 85-year-old man presenting with a 2-day history of mental deterioration and right-sided weakness. CT scan revealed a biconvex-shaped hyperdense mass mixed with various densities of blood along the left temporoparietal cerebral convexity, which was misinterpreted as AEDH preoperatively. Emergency craniectomy was performed, but no AEDH was found beneath the skull. In the subdural space, encapsulated ASDH was located. En block resection of encapsulated ASDH was done. Emergency craniectomy confirmed that the preoperatively diagnosed AEDH was an encapsulated ASDH postoperatively. Radiologic studies of AEDH-like SDH allow us to establish an easy differential diagnosis between AEDH and ASDH by distinct features. More histological studies will provide us information on the mechanism underlying encapsulated ASDH. PMID:27169052

Design, characterisation and application of alginate-based encapsulated pig liver esterase.

PubMed

Pauly, Jan; Gröger, Harald; Patel, Anant V

2018-06-05

Encapsulation of hydrolases in biopolymer-based hydrogels often suffers from low activities and encapsulation efficiencies along with high leaching and unsatisfactory recycling properties. Exemplified for the encapsulation of pig liver esterase the coating of alginate and chitosan beads have been studied by creating various biopolymer hydrogel beads. Enzyme activity and encapsulation efficiency were notably enhanced by chitosan coating of alginate beads while leaching remained nearly unchanged. This was caused by the enzymatic reaction acidifying the matrix, which increased enzyme retention through enhanced electrostatic enzyme-alginate interaction but decreased activity through enzyme deactivation. A practical and ready-to-use method for visualising pH in beads during reaction by co-encapsulation of a conventional pH indicator was also found. Our method proves that pH control inside the beads can only be realised by buffering. The resulting beads provided a specific activity of 0.267 μmol ∙ min -1 ∙ mg -1 , effectiveness factor 0.88, encapsulation efficiency of 88%, 5% leaching and good recycling properties. This work will contribute towards better understanding and application of encapsulated hydrolases for enzymatic syntheses. Copyright © 2018 Elsevier B.V. All rights reserved.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Astrophysics Data System (ADS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-10-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Technical Reports Server (NTRS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-01-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

Improving oxidative stability of echium oil emulsions fabricated by Microfluidics: Effect of ionic gelation and phenolic compounds.

PubMed

Comunian, Talita A; Ravanfar, Raheleh; de Castro, Inar Alves; Dando, Robin; Favaro-Trindade, Carmen S; Abbaspourrad, Alireza

2017-10-15

Echium oil is rich in omega-3 fatty acids, which are important because of their benefits to human health; it is, however, unstable. The objective of this work was the coencapsulation of echium oil and quercetin or sinapic acid by microfluidic and ionic gelation techniques. The treatments were analyzed utilizing optical and scanning electron microscopy, encapsulation yield, particle size, thermogravimetry, Fourier transform infrared spectroscopy, stability under stress conditions, and oil oxidative/phenolic compound stability for 30days at 40°C. High encapsulation yield values were obtained (91-97% and 77-90% for the phenolic compounds and oil) and the encapsulated oil was almost seven times more stable than the non-encapsulated oil (0.34 vs 2.42mgMDA/kg oil for encapsulated and non-encapsulated oil, respectively). Encapsulation was shown to promote oxidative stability, allowing new vehicles for the application of these compounds in food without the use of solvents and high temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural and oxidative stabilization of spray dried fish oil microencapsulates with gum arabic and sage polyphenols: Characterization and release kinetics.

PubMed

Binsi, P K; Nayak, Natasha; Sarkar, P C; Jeyakumari, A; Muhamed Ashraf, P; Ninan, George; Ravishankar, C N

2017-03-15

The synergistic efficacy of gum arabic and sage polyphenols in stabilising capsule wall and protecting fish oil encapsulates from heat induced disruption and oxidative deterioration during spray drying was assessed. The emulsions prepared with sodium caseinate as wall polymer, gum arabic as wall co-polymer and sage extract as wall stabiliser was spray dried using a single fluid nozzle. Fish oil encapsulates stabilised with gum arabic and sage extract (SOE) exhibited significantly higher encapsulation efficiency compared to encapsulates containing gum arabic alone (FOE). Scanning electron microscopic and atomic force microscopic images revealed uniform encapsulates with good sphericity and smooth surface for SOE, compared to FOE powder. In vitro oil release of microencapsulates indicated negligible oil release in buffered saline whereas more than 80% of the oil loaded in encapsulates were released in simulated GI fluids. The encapsulates containing sage extract showed a lower rate of lipid oxidation during storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Encapsulation-free controlled release: Electrostatic adsorption eliminates the need for protein encapsulation in PLGA nanoparticles

PubMed Central

Pakulska, Malgosia M.; Elliott Donaghue, Irja; Obermeyer, Jaclyn M.; Tuladhar, Anup; McLaughlin, Christopher K.; Shendruk, Tyler N.; Shoichet, Molly S.

2016-01-01

Encapsulation of therapeutic molecules within polymer particles is a well-established method for achieving controlled release, yet challenges such as low loading, poor encapsulation efficiency, and loss of protein activity limit clinical translation. Despite this, the paradigm for the use of polymer particles in drug delivery has remained essentially unchanged for several decades. By taking advantage of the adsorption of protein therapeutics to poly(lactic-co-glycolic acid) (PLGA) nanoparticles, we demonstrate controlled release without encapsulation. In fact, we obtain identical, burst-free, extended-release profiles for three different protein therapeutics with and without encapsulation in PLGA nanoparticles embedded within a hydrogel. Using both positively and negatively charged proteins, we show that short-range electrostatic interactions between the proteins and the PLGA nanoparticles are the underlying mechanism for controlled release. Moreover, we demonstrate tunable release by modifying nanoparticle concentration, nanoparticle size, or environmental pH. These new insights obviate the need for encapsulation and offer promising, translatable strategies for a more effective delivery of therapeutic biomolecules. PMID:27386554

Effect of Photon Radiations in Semi-Rigid Artificial Tissue Sensitized by Protoporphyrin IX Encapsulated with Silica Nanoparticles

NASA Astrophysics Data System (ADS)

Makhadmeh, Ghaseb N.; Aziz, Azlan Abdul; Razak, Khairunisak Abdul; Al-Akhras, M.-Ali H.

2018-02-01

This study involves the synthesis of Protoporphyrin IX (PpIX) encapsulated with Silica Nanoparticles (SiNPs) as an application for Photodynamic therapy. Semi-rigid artificial tissues with optical features similar to human tissue were used as sample materials to ascertain the efficacy of PpIX encapsulated with SiNPs. The disparity in optical characteristics (transmittance, reflectance, scattering, and absorption) of tissues treated with encapsulated PpIX and naked PpIX under light exposure (Intensity at 408 nm ~1.19 mW/cm2) was explored. The optimal exposure times required for naked PpIX and SiNPs encapsulated PpIX to engulf Red Blood Cells (RBCs) in the artificial tissue were subsequently measured. Comparative analysis showed that the encapsulated PpIX has a 91.5 % higher efficacy than naked PpIX. The results prove the applicability of PpIX encapsulated with SiNP on artificial tissue and possible use on human tissue.

Encapsulation and delivery of food ingredients using starch based systems.

PubMed

Zhu, Fan

2017-08-15

Functional ingredients can be encapsulated by various wall materials for controlled release in food and digestion systems. Starch, as one of the most abundant natural carbohydrate polymers, is non-allergenic, GRAS, and cheap. There has been increasing interest of using starch in native and modified forms to encapsulate food ingredients such as flavours, lipids, polyphenols, carotenoids, vitamins, enzymes, and probiotics. Starches from various botanical sources in granular or amorphous forms are modified by chemical, physical, and/or enzymatic means to obtain the desired properties for targeted encapsulation. Other wall materials are also employed in combination with starch to facilitate some types of encapsulation. Various methods of crafting the starch-based encapsulation such as electrospinning, spray drying, antisolvent, amylose inclusion complexation, and nano-emulsification are introduced in this mini-review. The physicochemical and structural properties of the particles are described. The encapsulation systems can positively influence the controlled release of food ingredients in food and nutritional applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method Of Making Solar Collectors By In-Situ Encapsulation Of Solar Cells

DOEpatents

Carrie, Peter J.; Chen, Kingsley D. D.

2000-10-24

A method of making solar collectors by encapsulating photovoltaic cells within a base of an elongated solar collector wherein heat and pressure are applied to the cells in-situ, after an encapsulating material has been applied. A tool is fashioned having a bladder expandable under gas pressure, filling a region of the collector where the cells are mounted. At the same time, negative pressure is applied outside of the bladder, enhancing its expansion. The bladder presses against a platen which contacts the encapsulated cells, causing outgassing of the encapsulant, while heat cures the encapsulant. After curing, the bladder is deflated and the tool may be removed from the collector and base and reflective panels put into place, if not already there, thereby allowing the solar collector to be ready for use.

Accelerated/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory California Institute of Technology for the encapsulation task of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Kolyer, J. M.

1978-01-01

An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants, substrates, and types of circuitry. One common failure mode was corrosion of circuitry and solar cell metallization due to moisture penetration. Another was darkening and/or opacification of encapsulant. A test program plan was proposed. It includes multicondition accelerated exposure. Another method was hyperaccelerated photochemical exposure using a solar concentrator. It simulates 20 year of sunlight exposure in a short period of one to two weeks. The study was beneficial in identifying some cost effective encapsulants and array designs.

Frequency regulator for synchronous generators

DOEpatents

Karlicek, Robert F.

1982-01-01

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.

Simulation of Quantum Phenomena in Nanowire Sensors

DTIC Science & Technology

2014-12-17

Ag and Pt atoms: search for nanocatalysts, Journal of Physics B: Atomic, Molecular and Optical Physics, (07 2011): 0. doi: 10.1088/0953- 4075/44...International Advisory Committee, African Laser Centre Annual Workshop 3-5 Nov. 2014, Moroccan Foundation for Advanced Science, Innovation & Research...atoms encapsulated inside C180 and C240 we found: 1) The Xe-C180 and Xe-C240 binding energies along some high symmetry directions showed the

Encapsulating Moral Dilemma through Short Story: Challenging Pre-Service Teachers to Critically Think about the Student/Teacher Personality and Leadership Dynamic

ERIC Educational Resources Information Center

Lennon, Sean M.

2007-01-01

Pre-service teachers and education students in three different classes (N = 53) were directed to read a short story by Mark Twain titled "Heaven or Hell?" written within a compilation of short stories late in his career. The story, "Heaven or Hell?" illustrates a koan, or an unanswerable moral or ethical dilemma. The students,…

Two antibacterial C-type lectins from crustacean, Eriocheir sinensis, stimulated cellular encapsulation in vitro.

PubMed

Jin, Xing-Kun; Li, Shuang; Guo, Xiao-Nv; Cheng, Lin; Wu, Min-Hao; Tan, Shang-Jian; Zhu, You-Ting; Yu, Ai-Qing; Li, Wei-Wei; Wang, Qun

2013-12-01

The first step of host fighting against pathogens is that pattern recognition receptors recognized pathogen-associated molecular patterns. However, the specificity of recognition within the innate immune molecular of invertebrates remains largely unknown. In the present study, we investigated how invertebrate pattern recognition receptor (PRR) C-type lectins might be involved in the antimicrobial response in crustacean. Based on our previously obtained completed coding regions of EsLecA and EsLecG in Eriocheir sinensis, the recombinant EsLectin proteins were produced via prokaryotic expression system and affinity chromatography. Subsequently, both rEsLecA and rEsLecG were discovered to have wide spectrum binding activities towards microorganisms, and their microbial-binding was calcium-independent. Moreover, the binding activities of both rEsLecA and rEsLecG induced the aggregation against microbial pathogens. Both microorganism growth inhibitory activities assays and antibacterial activities assays revealed their capabilities of suppressing microorganisms growth and directly killing microorganisms respectively. Furthermore, the encapsulation assays signified that both rEsLecA and rEsLecG could stimulate the cellular encapsulation in vitro. Collectively, data presented here demonstrated the successful expression and purification of two C-type lectins proteins in the Chinese mitten crab, and their critical role in the innate immune system of an invertebrate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Noninvasive visualization of in vivo release and intratumoral distribution of surrogate MR contrast agent using the dual MR contrast technique.

PubMed

Onuki, Yoshinori; Jacobs, Igor; Artemov, Dmitri; Kato, Yoshinori

2010-09-01

A direct evaluation of the in vivo release profile of drugs from carriers is a clinical demand in drug delivery systems, because drug release characterized in vitro correlates poorly with in vivo release. The purpose of this study is to demonstrate the in vivo applicability of the dual MR contrast technique as a useful tool for noninvasive monitoring of the stability and the release profile of drug carriers, by visualizing in vivo release of the encapsulated surrogate MR contrast agent from carriers and its subsequent intratumoral distribution profile. The important aspect of this technique is that it incorporates both positive and negative contrast agents within a single carrier. GdDTPA, superparamagnetic iron oxide nanoparticles, and 5-fluorouracil were encapsulated in nano- and microspheres composed of poly(D,L-lactide-co-glycolide), which was used as a model carrier. In vivo studies were performed with orthotopic xenograft of human breast cancer. The MR-based technique demonstrated here has enabled visualization of the delivery of carriers, and release and intratumoral distribution of the encapsulated positive contrast agent. This study demonstrated proof-of-principle results for the noninvasive monitoring of in vivo release and distribution profiles of MR contrast agents, and thus, this technique will make a great contribution to the field. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Preparation, physical characterization, and stability of Ferrous-Chitosan microcapsules using different iron sources

NASA Astrophysics Data System (ADS)

Handayani, Noer Abyor; Luthfansyah, M.; Krisanti, Elsa; Kartohardjono, Sutrasno; Mulia, Kamarza

2017-11-01

Dietary modification, supplementation and food fortification are common strategies to alleviate iron deficiencies. Fortification of food is an effective long-term approach to improve iron status of populations. Fortification by adding iron directly to food will cause sensory problems and decrease its bioavailability. The purpose of iron encapsulation is: (1) to improve iron bioavailability, by preventing oxidation and contact with inhibitors and competitors; and (2) to disguise the rancid aroma and flavor of iron. A microcapsule formulation of two suitable iron compounds (iron II fumarate and iron II gluconate) using chitosan as a biodegradable polymer will be very important. Freeze dryer was also used for completing the iron microencapsulation process. The main objective of the present study was to prepare and characterize the iron-chitosan microcapsules. Physical characterization, i.e. encapsulation efficiency, iron loading capacity, and SEM, were also discussed in this paper. The stability of microencapsulated iron under simulated gastrointestinal conditions was also investigated, as well. Both iron sources were highly encapsulated, ranging from 71.5% to 98.5%. Furthermore, the highest ferrous fumarate and ferrous gluconate loaded were 1.9% and 4.8%, respectively. About 1.04% to 9.17% and 45.17% to 75.19% of Fe II and total Fe, were released in simulated gastric fluid for two hours and in simulated intestinal fluid for six hours, respectively.

Creation of novel structured carbon nanotubes using different-polarity ion plasmas

NASA Astrophysics Data System (ADS)

Hatakeyama, Rikizo; Hirata, Takamichi; Jeong, Goo-Hwan

2004-02-01

In order to develop novel functional carbon-based nanomaterials, an original approach using plasma technology has been performed. When positive or negative bias voltages are applied to a substrate that is covered with single-walled carbon nanotubes (SWNTs) and immersed in alkali-fullerene plasmas, accelerated negative fullerene or positive alkali-metal ions are irradiated on the SWNTs through plasma sheaths in front of the substrate. Field emission gun transmission electron microscopy (FEG-TEM) images clearly show that drastic structural modifications such as severe bending of SWNT bundles and tube tip termination take place after the ion irradiation. Energy dispersive x-ray spectrometry confirms the existence of the elements Na, K and Cs in the samples after alkali-metal irradiation. In particular, Cs encapsulation inside the SWNTs is directly observed, the configuration of which is demonstrated to comprise three varieties by FEG-TEM and scanning TEM. In the case of C_{60}^{ - } irradiation by positive bias application, on the other hand, SWNTs encapsulating fullerene molecules are clearly observed. Furthermore, the fullerene encapsulation yield within the SWNTs linearly increases with an enhancement of the plasma density used. Finally, a sequential bias application with polarity change gives the possibility of formation of a nanojunction structure composed of Cs rows and C60 chains. It is worth emphasizing that our results open a new possibility for novel structured material synthesis using plasma technology.

Use of Silica-Encapsulated Pseudomonas sp. Strain NCIB 9816-4 in Biodegradation of Novel Hydrocarbon Ring Structures Found in Hydraulic Fracturing Waters

PubMed Central

Aukema, Kelly G.; Kasinkas, Lisa; Aksan, Alptekin

2014-01-01

The most problematic hydrocarbons in hydraulic fracturing (fracking) wastewaters consist of fused, isolated, bridged, and spiro ring systems, and ring systems have been poorly studied with respect to biodegradation, prompting the testing here of six major ring structural subclasses using a well-characterized bacterium and a silica encapsulation system previously shown to enhance biodegradation. The direct biological oxygenation of spiro ring compounds was demonstrated here. These and other hydrocarbon ring compounds have previously been shown to be present in flow-back waters and waters produced from hydraulic fracturing operations. Pseudomonas sp. strain NCIB 9816-4, containing naphthalene dioxygenase, was selected for its broad substrate specificity, and it was demonstrated here to oxidize fundamental ring structures that are common in shale-derived waters but not previously investigated with this or related enzymes. Pseudomonas sp. NCIB 9816-4 was tested here in the presence of a silica encasement, a protocol that has previously been shown to protect bacteria against the extremes of salinity present in fracking wastewaters. These studies demonstrate the degradation of highly hydrophobic compounds by a silica-encapsulated model bacterium, demonstrate what it may not degrade, and contribute to knowledge of the full range of hydrocarbon ring compounds that can be oxidized using Pseudomonas sp. NCIB 9816-4. PMID:24907321

Porous Fe2O3 Nanoframeworks Encapsulated within Three-Dimensional Graphene as High-Performance Flexible Anode for Lithium-Ion Battery.

PubMed

Jiang, Tiancai; Bu, Fanxing; Feng, Xiaoxiang; Shakir, Imran; Hao, Guolin; Xu, Yuxi

2017-05-23

Integrating nanoscale porous metal oxides into three-dimensional graphene (3DG) with encapsulated structure is a promising route but remains challenging to develop high-performance electrodes for lithium-ion battery. Herein, we design 3DG/metal organic framework composite by an excessive metal-ion-induced combination and spatially confined Ostwald ripening strategy, which can be transformed into 3DG/Fe 2 O 3 aerogel with porous Fe 2 O 3 nanoframeworks well encapsulated within graphene. The hierarchical structure offers highly interpenetrated porous conductive network and intimate contact between graphene and porous Fe 2 O 3 as well as abundant stress buffer nanospace for effective charge transport and robust structural stability during electrochemical processes. The obtained free-standing 3DG/Fe 2 O 3 aerogel was directly used as highly flexible anode upon mechanical pressing for lithium-ion battery and showed an ultrahigh capacity of 1129 mAh/g at 0.2 A/g after 130 cycles and outstanding cycling stability with a capacity retention of 98% after 1200 cycles at 5 A/g, which is the best results that have been reported so far. This study offers a promising route to greatly enhance the electrochemical properties of metal oxides and provides suggestive insights for developing high-performance electrode materials for electrochemical energy storage.

Thermogelling chitosan and collagen composite hydrogels initiated with β-glycerophosphate for bone tissue engineering

PubMed Central

Wang, Limin; Stegemann, Jan P.

2010-01-01

Chitosan and collagen type I are naturally-derived materials used as cell carriers because of their ability to mimic the extracellular environment and direct cell function. In this study beta-glycerophosphate (beta-GP), an osteogenic medium supplement and a weak base, was used to simultaneously initiate gelation of pure chitosan, pure collagen, and chitosan-collagen composite materials at physiological pH and temperature. Adult human bone marrow-derived stem cells (hBMSC) encapsulated in such hydrogels at chitosan/collagen ratios of 100/0, 65/35, 25/75, and 0/100 wt% exhibited high viability at day 1 after encapsulation, but DNA content dropped by about half over 12 days in pure chitosan materials while it increased two-fold in materials containing collagen. Collagen-containing materials compacted more strongly and were significantly stiffer than pure chitosan gels. In monolayer culture, exposure of hBMSC to beta-GP resulted in decreased cell metabolic activity that varied with concentration and exposure time, but washing effectively removed excess beta-GP from hydrogels. The presence of chitosan in materials resulted in higher expression of osterix and bone sialoprotein genes in medium with and without osteogenic supplements. Chitosan also increased alkaline phosphatase activity and calcium deposition in osteogenic medium. Chitosan-collagen composite materials have potential as matrices for cell encapsulation and delivery, or as in situ gel-forming materials for tissue repair. PMID:20170955

Thermogelling chitosan and collagen composite hydrogels initiated with beta-glycerophosphate for bone tissue engineering.

PubMed

Wang, Limin; Stegemann, Jan P

2010-05-01

Chitosan and collagen type I are naturally derived materials used as cell carriers because of their ability to mimic the extracellular environment and direct cell function. In this study beta-glycerophosphate (beta-GP), an osteogenic medium supplement and a weak base, was used to simultaneously initiate gelation of pure chitosan, pure collagen, and chitosan-collagen composite materials at physiological pH and temperature. Adult human bone marrow-derived stem cells (hBMSC) encapsulated in such hydrogels at chitosan/collagen ratios of 100/0, 65/35, 25/75, and 0/100 wt% exhibited high viability at day 1 after encapsulation, but DNA content dropped by about half over 12 days in pure chitosan materials while it increased twofold in materials containing collagen. Collagen-containing materials compacted more strongly and were significantly stiffer than pure chitosan gels. In monolayer culture, exposure of hBMSC to beta-GP resulted in decreased cell metabolic activity that varied with concentration and exposure time, but washing effectively removed excess beta-GP from hydrogels. The presence of chitosan in materials resulted in higher expression of osterix and bone sialoprotein genes in medium with and without osteogenic supplements. Chitosan also increased alkaline phosphatase activity and calcium deposition in osteogenic medium. Chitosan-collagen composite materials have potential as matrices for cell encapsulation and delivery, or as in situ gel-forming materials for tissue repair. Copyright 2010 Elsevier Ltd. All rights reserved.

Effects of interaction between temperature conditions and copper exposure on immune defense and other life-history traits of the blow fly Protophormia terraenovae.

PubMed

Pölkki, Mari; Kangassalo, Katariina; Rantala, Markus J

2014-01-01

Environmental pollution is considered one of the major threats to organisms. Direct effects of heavy metal pollution on various life-history traits are well recognized, while the effects of potential interactions between two distinct environmental conditions on different traits are poorly understood. Here, we have tested the effects of interactions between temperature conditions and heavy metal exposure on innate immunity and other life-history traits. Maggots of the blow fly Protophormia terraenovae were reared on either copper-contaminated or uncontaminated food, under three different temperature environments. Encapsulation response, body mass, and development time were measured for adult flies that were not directly exposed to copper. We found that the effects of copper exposure on immunity and other traits are temperature-dependent, suggesting that the ability to regulate toxic compounds in body tissues might depend on temperature conditions. Furthermore, we found that temperature has an effect on sex differences in immune defense. Males had an encapsulation response at higher temperatures stronger than that of females. Our results indicate that the effects of environmental conditions on different traits are much more intricate than what can be predicted. This is something that should be considered when conducting immunological experiments or comparing results of previous studies.

Is Cu a stable electrode material in hybrid perovskite solar cells for a 30-year lifetime?

DOE PAGES

Zhao, Jingjing; Zheng, Xiaopeng; Deng, Yehao; ...

2016-10-28

One grand challenge for long-lived perovskite solar cells is that the common electrode materials in solar cells, such as silver and aluminum or even gold, strongly react with hybrid perovskites. Here we report the evaluation of the potential of copper (Cu) as the electrode material in perovskite solar cells for long-term stability. In encapsulated devices which limit exposure to oxygen and moisture, Cu in direct contact with CH 3NH 3PbI 3 showed no reaction at laboratory time scales, and is predicted to be stable for almost 170 years at room temperature and over 22 years at the nominal operating cellmore » temperature of 40 °C. No diffusion of Cu into CH 3NH 3PbI 3 has been observed after thermal annealing for over 100 hours at 80 °C, nor does Cu cause charge trap states in direct contact with CH 3NH 3PbI 3 after long-term thermal annealing or illumination. High performance devices with efficiency above 20% with Cu electrode retains 98% of the initial efficiency after 816 hours storage in ambient environment without encapsulation. Finally, the results indicate Cu is a promising low-cost electrode material for perovskite solar cells for long-term operation.« less

Site-directed decapsulation of bolaamphiphilic vesicles with enzymatic cleavable surface groups.

PubMed

Popov, Mary; Grinberg, Sarina; Linder, Charles; Waner, Tal; Levi-Hevroni, Bosmat; Deckelbaum, Richard J; Heldman, Eliahu

2012-06-10

Stable nano-sized vesicles with a monolayer encapsulating membrane were prepared from novel bolaamphiphiles with choline ester head groups. The head groups were covalently bound to the alkyl chain of the bolaamphiphiles either via the nitrogen atom of the choline moiety, or via the choline ester's methyl group. Both types of bolaamphiphiles competed with acetylthiocholine for binding to acetylcholine esterase (AChE), yet, only the choline ester head groups bound to the alkyl chain via the nitrogen atom of the choline moiety were hydrolyzed by the enzyme. Likewise, only vesicles composed of bolaamphiphiles with head groups that were hydrolyzed by AChE released their encapsulated material upon exposure to the enzyme. Injection of carboxyfluorescein (CF)-loaded vesicles with cleavable choline ester head groups into mice resulted in the accumulation of CF in tissues that express high AChE activity, including the brain. By comparison, when vesicles with choline ester head groups that are not hydrolyzed by AChE were injected into mice, there was no accumulation of CF in tissues that highly express the enzyme. These results imply that bolaamphiphilic vesicles with surface groups that are substrates to enzymes which are highly expressed in target organs may potentially be used as a drug delivery system with controlled site-directed drug release. Copyright © 2011 Elsevier B.V. All rights reserved.

Genetic and biochemical investigations of the role of MamP in redox control of iron biomineralization in Magnetospirillum magneticum.

PubMed

Jones, Stephanie R; Wilson, Tiffany D; Brown, Margaret E; Rahn-Lee, Lilah; Yu, Yi; Fredriksen, Laura L; Ozyamak, Ertan; Komeili, Arash; Chang, Michelle C Y

2015-03-31

Magnetotactic bacteria have evolved complex subcellular machinery to construct linear chains of magnetite nanocrystals that allow the host cell to sense direction. Each mixed-valent iron nanoparticle is mineralized from soluble iron within a membrane-encapsulated vesicle termed the magnetosome, which serves as a specialized compartment that regulates the iron, redox, and pH environment of the growing mineral. To dissect the biological components that control this process, we have carried out a genetic and biochemical study of proteins proposed to function in iron mineralization. In this study, we show that the redox sites of c-type cytochromes of the Magnetospirillum magneticum AMB-1 magnetosome island, MamP and MamT, are essential to their physiological function and that ablation of one or both heme motifs leads to loss of function, suggesting that their ability to carry out redox chemistry in vivo is important. We also develop a method to heterologously express fully heme-loaded MamP from AMB-1 for in vitro biochemical studies, which show that its Fe(III)-Fe(II) redox couple is set at an unusual potential (-89 ± 11 mV) compared with other related cytochromes involved in iron reduction or oxidation. Despite its low reduction potential, it remains competent to oxidize Fe(II) to Fe(III) and mineralize iron to produce mixed-valent iron oxides. Finally, in vitro mineralization experiments suggest that Mms mineral-templating peptides from AMB-1 can modulate the iron redox chemistry of MamP.

Integration of Artificial Photosynthesis System for Enhanced Electronic Energy-Transfer Efficacy: A Case Study for Solar-Energy Driven Bioconversion of Carbon Dioxide to Methanol.

PubMed

Ji, Xiaoyuan; Su, Zhiguo; Wang, Ping; Ma, Guanghui; Zhang, Songping

2016-09-01

Biocatalyzed artificial photosynthesis systems provide a promising strategy to store solar energy in a great variety of chemicals. However, the lack of direct interface between the light-capturing components and the oxidoreductase generally hinders the trafficking of the chemicals and photo-excited electrons into the active center of the redox biocatalysts. To address this problem, a completely integrated artificial photosynthesis system for enhanced electronic energy-transfer efficacy is reported by combining co-axial electrospinning/electrospray and layer-by-layer (LbL) self-assembly. The biocatalysis part including multiple oxidoreductases and coenzymes NAD(H) was in situ encapsulated inside the lumen polyelectrolyte-doped hollow nanofibers or microcapsules fabricated via co-axial electrospinning/electrospray; while the precise and spatial arrangement of the photocatalysis part, including electron mediator and photosensitizer for photo-regeneration of the coenzyme, was achieved by ion-exchange interaction-driven LbL self-assembly. The feasibility and advantages of this integrated artificial photosynthesis system is fully demonstrated by the catalyzed cascade reduction of CO2 to methanol by three dehydrogenases (formate, formaldehyde, and alcohol dehydrogenases), incorporating the photo-regeneration of NADH under visible-light irradiation. Compared to solution-based systems, the methanol yield increases from 35.6% to 90.6% using the integrated artificial photosynthesis. This work provides a novel platform for the efficient and sustained production of a broad range of chemicals and fuels from sunlight. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sulfur Mustard Toxicity Following Dermal Exposure

PubMed Central

Paromov, Victor; Suntres, Zacharias; Smith, Milton; Stone, William L.

2007-01-01

Objective: Sulfur mustard (bis-2-(chloroethyl) sulfide) is a chemical warfare agent (military code: HD) causing extensive skin injury. The mechanisms underlying HD-induced skin damage are not fully elucidated. This review will critically evaluate the evidence showing that oxidative stress is an important factor in HD skin toxicity. Oxidative stress results when the production of reactive oxygen (ROS) and/or reactive nitrogen oxide species (RNOS) exceeds the capacity of antioxidant defense mechanisms. Methods: This review will discuss the role of oxidative stress in the pathophysiology of HD skin toxicity in both in vivo and in vitro model systems with emphasis on the limitations of the various model systems. Evidence supporting the therapeutic potential of antioxidants and antioxidant liposomes will be evaluated. Antioxidant liposomes are effective vehicles for delivering both lipophilic (incorporated into the lipid bilayers) and water-soluble (encapsulated in the aqueous inner-spaces) antioxidants to skin. The molecular mechanisms interconnecting oxidative stress to HD skin toxicity are also detailed. Results: DNA repair and inflammation, in association with oxidative stress, induce intracellular events leading to apoptosis or to a programmable form of necrosis. The free radical, nitric oxide (NO), is of considerable interest with respect to the mechanisms of HD toxicity. NO signaling pathways are important in modulating inflammation, cell death, and wound healing in skin cells. Conclusions: Potential future directions are summarized with emphasis on a systems biology approach to studying sulfur mustard toxicity to skin as well as the newly emerging area of redox proteomics. PMID:18091984

Module encapsulation technology

NASA Technical Reports Server (NTRS)

Willis, P.

1986-01-01

The identification and development techniques for low-cost module encapsulation materials were reviewed. Test results were displayed for a variety of materials. The improved prospects for modeling encapsulation systems for life prediction were reported.

Design, analysis and test verification of advanced encapsulation systems

NASA Technical Reports Server (NTRS)

Garcia, A., III; Kallis, J. M.; Trucker, D. C.

1983-01-01

Analytical models were developed to perform optical, thermal, electrical and structural analyses on candidate encapsulation systems. From these analyses several candidate encapsulation systems were selected for qualification testing.

Bioactive Encapsulation for Military Food Applications: Request for Enhanced Nano and Micro Particle Fabrication and Characterization Facilities

DTIC Science & Technology

2016-01-25

2013 21-Jul-2014 Approved for Public Release; Distribution Unlimited Final Report: Bioactive Encapsulation for Military Food Applications: Request for...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: Bioactive Encapsulation for Military Food Applications...Total Number: ...... Inventions (DD882) Scientific Progress Equipment was purchased. Technology Transfer 1 Bioactive Encapsulation for Military Food

Functional Design of Dielectric-Metal-Dielectric-Based Thin-Film Encapsulation with Heat Transfer and Flexibility for Flexible Displays.

PubMed

Kwon, Jeong Hyun; Choi, Seungyeop; Jeon, Yongmin; Kim, Hyuncheol; Chang, Ki Soo; Choi, Kyung Cheol

2017-08-16

In this study, a new and efficient dielectric-metal-dielectric-based thin-film encapsulation (DMD-TFE) with an inserted Ag thin film is proposed to guarantee the reliability of flexible displays by improving the barrier properties, mechanical flexibility, and heat dissipation, which are considered to be essential requirements for organic light-emitting diode (OLED) encapsulation. The DMD-TFE, which is composed of Al 2 O 3 , Ag, and a silica nanoparticle-embedded sol-gel hybrid nanocomposite, shows a water vapor transmission rate of 8.70 × 10 -6 g/m 2 /day and good mechanical reliability at a bending radius of 30 mm, corresponding to 0.41% strain for 1000 bending cycles. The electrical performance of a thin-film encapsulated phosphorescent organic light-emitting diode (PHOLED) was identical to that of a glass-lid encapsulated PHOLED. The operational lifetimes of the thin-film encapsulated and glass-lid encapsulated PHOLEDs are 832 and 754 h, respectively. After 80 days, the thin-film encapsulated PHOLED did not show performance degradation or dark spots on the cell image in a shelf-lifetime test. Finally, the difference in lifetime of the OLED devices in relation to the presence and thickness of a Ag film was analyzed by applying various TFE structures to fluorescent organic light-emitting diodes (FOLEDs) that could generate high amounts of heat. To demonstrate the difference in heat dissipation effect among the TFE structures, the saturated temperatures of the encapsulated FOLEDs were measured from the back side surface of the glass substrate, and were found to be 67.78, 65.12, 60.44, and 39.67 °C after all encapsulated FOLEDs were operated at an initial luminance of 10 000 cd/m 2 for sufficient heat generation. Furthermore, the operational lifetime tests of the encapsulated FOLED devices showed results that were consistent with the measurements of real-time temperature profiles taken with an infrared camera. A multifunctional hybrid thin-film encapsulation based on a dielectric-metal-dielectric structure was thus effectively designed considering the transmittance, gas-permeation barrier properties, flexibility, and heat dissipation effect by exploiting the advantages of each separate layer.

Ibuprofen-in-cyclodextrin-in-W/O/W emulsion - Improving the initial and long-term encapsulation efficiency of a model active ingredient.

PubMed

Hattrem, Magnus N; Kristiansen, Kåre A; Aachmann, Finn L; Dille, Morten J; Draget, Kurt I

2015-06-20

A challenge in formulating water-in-oil-in-water (W/O/W) emulsions is the uncontrolled release of the encapsulated compound prior to application. Pharmaceuticals and nutraceuticals usually have amphipathic nature, which may contribute to leakage of the active ingredient. In the present study, cyclodextrins (CyDs) were used to impart a change in the relative polarity and size of a model compound (ibuprofen) by the formation of inclusion complexes. Various inclusion complexes (2-hydroxypropyl (HP)-β-CyD-, α-CyD- and γ-CyD-ibuprofen) were prepared and presented within W/O/W emulsions, and the initial and long-term encapsulation efficiency was investigated. HP-β-CyD-ibuprofen provided the highest encapsulation of ibuprofen in comparison to a W/O/W emulsion with unassociated ibuprofen confined within the inner water phase, with a four-fold increase in the encapsulation efficiency. An improved, although lower, encapsulation efficiency was obtained for the inclusion complex γ-CyD-ibuprofen in comparison to HP-β-CyD-ibuprofen, whereas α-CyD-ibuprofen had a similar encapsulation efficiency to that of unassociated ibuprofen. The lower encapsulation efficiency of ibuprofen in combination with α-CyD and γ-CyD was attributed to a lower association constant for the γ-CyD-ibuprofen inclusion complex and the ability of α-CyD to form inclusion complexes with fatty acids. For the W/O/W emulsion prepared with HP-β-CyD-ibuprofen, the highest encapsulation of ibuprofen was obtained at hyper- and iso-osmotic conditions and by using an excess molar ratio of CyD to ibuprofen. In the last part of the study, it was suggested that the chemical modification of the HP-β-CyD molecule did not influence the encapsulation of ibuprofen, as a similar encapsulation efficiency was obtained for an inclusion complex prepared with mono-1-glucose-β-CyD. Copyright © 2015 Elsevier B.V. All rights reserved.

Preserving viability of Lactobacillus rhamnosus GG in vitro and in vivo by a new encapsulation system.

PubMed

Li, Ran; Zhang, Yufeng; Polk, D Brent; Tomasula, Peggy M; Yan, Fang; Liu, LinShu

2016-05-28

Probiotics have shown beneficial effects on health and prevention of diseases in humans. However, a concern for application of probiotics is the loss of viability during storage and gastrointestinal transit. The aim of this study was to develop an encapsulation system to preserve viability of probiotics when they are administrated orally and apply Lactobacillus rhamnosus GG (LGG) as a probiotic model to evaluate the effectiveness of this approach using in vitro and in vivo experiments. LGG was encapsulated in hydrogel beads prepared using pectin, a food grade polysaccharide, glucose, and calcium chloride, and lyophilized by freeze-drying. Encapsulated LGG was cultured in vitro under the condition that mimicked the physiological environment of the human gastrointestinal tract. Compared to non-encapsulated LGG, encapsulation increased tolerance of LGG in the acid condition, protected LGG from protease digestion, and improved shelf time when stored at the ambient condition, in regard of survivability and production of p40, a known LGG-derived protein involved in LGG's beneficial effects on intestinal homeostasis. To evaluate the effects of encapsulation on p40 production in vivo and prevention of intestinal inflammation by LGG, mice were gavaged with LGG containing beads and treated with dextran sulphate sodium (DSS) to induce intestinal injury and colitis. Compared to non-encapsulated LGG, encapsulated LGG enhanced more p40 production in mice, and exerted higher levels of effects on prevention of DSS-induced colonic injury and colitis and suppression of pro-inflammatory cytokine production. These data indicated that the encapsulation system developed in this study preserves viability of LGG in vitro and in vivo, leading to longer shelf time and enhancing the functions of LGG in the gastrointestinal tract. Thus, this encapsulation approach may have the potential application for improving efficacy of probiotics. Copyright © 2016 Elsevier B.V. All rights reserved.

Alginate-gelatin encapsulation of human endothelial cells promoted angiogenesis in in vivo and in vitro milieu.

PubMed

Nemati, Sorour; Rezabakhsh, Aysa; Khoshfetrat, Ali Baradar; Nourazarian, Alireza; Biray Avci, Çığır; Goker Bagca, Bakiye; Alizadeh Sardroud, Hamed; Khaksar, Majid; Ahmadi, Mahdi; Delkhosh, Aref; Sokullu, Emel; Rahbarghazi, Reza

2017-12-01

Up to present, many advantages have been achieved in the field of cell-based therapies by applying sophisticated methodologies and delivery approaches. Microcapsules are capable to provide safe microenvironment for cells during transplantation in a simulated physiological 3D milieu. Here, we aimed to investigate the effect of alginate-gelatin encapsulation on angiogenic behavior of human endothelial cells over a period of 5 days. Human umbilical vein endothelial cells were encapsulated by alginate-gelatin substrate and incubated for 5 days. MTT and autophagy PCR array analysis were used to monitor cell survival rate. For in vitro angiogenesis analysis, cell distribution of Tie-1, Tie-2, VEGFR-1, and VEGFR-2 were detected by ELISA. In addition to in vitro tubulogenesis assay, we monitored the expression of VE-cadherin by Western blotting. The migration capacity of encapsulated HUVECs was studied by measuring MMP-2 and MMP-9 via gelatin zymography. The in vivo angiogenic potential of encapsulated HUVECs was analyzed in immune-compromised mouse implant model during 7 days post-transplantation. We demonstrated that encapsulation promoted HUVECs cell survival and proliferation. Compared to control, no significant differences were observed in autophagic status of encapsulated cells (p > 0.05). The level of Tie-1, Tie-2, VEGFR-1, and VEGFR-2 were increased, but did not reach to significant levels. Encapsulation decreased MMP-2, -9 activity and increased the VE-cadherin level in enclosed cells (p < 0.05). Moreover, an enhanced in vivo angiogenic response of encapsulated HUVECs was evident as compared to non-capsulated cells (p < 0.05). These observations suggest that alginate-gelatin encapsulation can induce angiogenic response in in vivo and in vitro conditions. © 2017 Wiley Periodicals, Inc.

Enhanced Therapeutic and Long-Term Dynamic Vascularization Effects of Human Pluripotent Stem Cell-Derived Endothelial Cells Encapsulated in a Nanomatrix Gel.

PubMed

Lee, Shin-Jeong; Sohn, Young-Doug; Andukuri, Adinarayana; Kim, Sangsung; Byun, Jaemin; Han, Ji Woong; Park, In-Hyun; Jun, Ho-Wook; Yoon, Young-Sup

2017-11-14

Human pluripotent stem cell (hPSC)-derived endothelial cells (ECs) have limited clinical utility because of undefined components in the differentiation system and poor cell survival in vivo. Here, we aimed to develop a fully defined and clinically compatible system to differentiate hPSCs into ECs. Furthermore, we aimed to enhance cell survival, vessel formation, and therapeutic potential by encapsulating hPSC-ECs with a peptide amphiphile (PA) nanomatrix gel. We induced differentiation of hPSCs into the mesodermal lineage by culturing on collagen-coated plates with a glycogen synthase kinase 3β inhibitor. Next, vascular endothelial growth factor, endothelial growth factor, and basic fibroblast growth factor were added for endothelial lineage differentiation, followed by sorting for CDH5 (VE-cadherin). We constructed an extracellular matrix-mimicking PA nanomatrix gel (PA-RGDS) by incorporating the cell adhesive ligand Arg-Gly-Asp-Ser (RGDS) and a matrix metalloproteinase-2-degradable sequence. We then evaluated whether the encapsulation of hPSC-CDH5 + cells in PA-RGDS could enhance long-term cell survival and vascular regenerative effects in a hind-limb ischemia model with laser Doppler perfusion imaging, bioluminescence imaging, real-time reverse transcription-polymerase chain reaction, and histological analysis. The resultant hPSC-derived CDH5 + cells (hPSC-ECs) showed highly enriched and genuine EC characteristics and proangiogenic activities. When injected into ischemic hind limbs, hPSC-ECs showed better perfusion recovery and higher vessel-forming capacity compared with media-, PA-RGDS-, or human umbilical vein EC-injected groups. However, the group receiving the PA-RGDS-encapsulated hPSC-ECs showed better perfusion recovery, more robust and longer cell survival (> 10 months), and higher and prolonged angiogenic and vascular incorporation capabilities than the bare hPSC-EC-injected group. Surprisingly, the engrafted hPSC-ECs demonstrated previously unknown sustained and dynamic vessel-forming behavior: initial perivascular concentration, a guiding role for new vessel formation, and progressive incorporation into the vessels over 10 months. We generated highly enriched hPSC-ECs via a clinically compatible system. Furthermore, this study demonstrated that a biocompatible PA-RGDS nanomatrix gel substantially improved long-term survival of hPSC-ECs in an ischemic environment and improved neovascularization effects of hPSC-ECs via prolonged and unique angiogenic and vessel-forming properties. This PA-RGDS-mediated transplantation of hPSC-ECs can serve as a novel platform for cell-based therapy and investigation of long-term behavior of hPSC-ECs. © 2017 American Heart Association, Inc.

GESA--a two-dimensional processing system using knowledge base techniques.

PubMed

Rowlands, D G; Flook, A; Payne, P I; van Hoff, A; Niblett, T; McKee, S

1988-12-01

The successful analysis of two-dimensional (2-D) polyacrylamide electrophoresis gels demands considerable experience and understanding of the protein system under investigation as well as knowledge of the separation technique itself. The present work concerns the development of a computer system for analysing 2-D electrophoretic separations which incorporates concepts derived from artificial intelligence research such that non-experts can use the technique as a diagnostic or identification tool. Automatic analysis of 2-D gel separations has proved to be extremely difficult using statistical methods. Non-reproducibility of gel separations is also difficult to overcome using automatic systems. However, the human eye is extremely good at recognising patterns in images, and human intervention in semi-automatic computer systems can reduce the computational complexities of fully automatic systems. Moreover, the expertise and understanding of an "expert" is invaluable in reducing system complexity if it can be encapsulated satisfactorily in an expert system. The combination of user-intervention in the computer system together with the encapsulation of expert knowledge characterises the present system. The domain within which the system has been developed is that of wheat grain storage proteins (gliadins) which exhibit polymorphism to such an extent that cultivars can be uniquely identified by their gliadin patterns. The system can be adapted to other domains where a range of polymorpic protein sub-units exist. In its generalised form, the system can also be used for comparing more complex 2-D gel electrophoretic separations.

The permeability of EUDRAGIT RL and HEMA-MMA microcapsules to glucose and inulin.

PubMed

Douglas, J A; Sefton, M V

1990-10-05

Measurement of the rate of glucose diffusion from EUDGRAGIT RL and HEMA-MMA microcapsules coupled with a Thiele modulus/Biot number analysis of the glucose utilization rate suggests that pancreatic islets and CHO (Chinese hamster ovary) cells (at moderate to high cell densities) should not be adversely affected by the diffusion restrictions associated with these capsule membranes. The mass transfer coefficients for glucose at 20 degrees C were of the same order of magnitude for both capsules, based on release measurements: approximately 5 x 10(-6) cm/s for EUDRAGIT RL and approximately 2 x 10(-6) for HEMA-MMA. Inulin release from EUDRAGIT RL was slower than for glucose (mass transfer coefficient 14 +/- 4 x 10(-8) cm/s). The Thiele moduli were much less than 1, either for a single islet at the center of a capsule or CHO cells uniformly distributed throughout a capsule at 10(-6) cells/ mL, so that diffusion restrictions within the cells in EUDRAGIT RL or 800 microm HEMA-MMA capsules should be negligible. The ratio of external to internal diffusion resistance (Biot number) was less than 1, so that at most, only a small diffusion effect on glucose utilization should be expected (i.e., the overall effectiveness factors were greater than 0.8). These calculations were consistent with experimental observation of encapsulated islet behavior but not fully with CHO cell behavior. Permeability restricted cell viability and growth is potentially a major limitation of encapsulated cells; further analysis is warranted.

Selection of PLA polymers for the development of injectable prilocaine controlled release microparticles: usefulness of thermal analysis.

PubMed

Bragagni, Marco; Beneitez, Cristina; Martín, Cristina; Hernán Pérez de la Ossa, Dolores; Mura, Paola Angela; Gil-Alegre, María Esther

2013-01-30

The use of injectable local anaesthetics for the treatment of severe postoperative pain is limited by the short duration of the painkilling effect. Pre-formulation studies were carried out for the development of an injectable microparticle formulation for controlled release of prilocaine, an amino-amide type local anaesthetic suitable for intravenous, subcutaneous and intramuscular administration. To the best of our knowledge, the encapsulation of prilocaine into microparticles has not been investigated yet. Three different poly-lactic-acid (PLA) polymers were separately employed for the preparation of the microparticles. Thermal analyses by differential scanning calorimetry (DSC) were carried out for the characterization of the raw materials, to assess the drug-polymer compatibility and miscibility, to investigate the effects of the production process on the components. Empty and prilocaine loaded microparticles were prepared by double emulsion method. All formulations were fully characterized in terms of drug content, morphology, size and in vitro drug release. The preliminary value of PRL solubility in the polymer material determined by DSC was evaluated and discussed as a predictive value for encapsulation efficiency and controlled release. DSC analysis turned out to be a usefulness tool for a fast polymer selection. Microparticles prepared with PLA R202 and R203S showed desirable characteristics for subcutaneous administration and could represent two promising formulations for the development of innovative pharmacological tools in the treatment of postoperative pain. Copyright © 2012 Elsevier B.V. All rights reserved.

Durable crystalline Si photovoltaic modules based on silicone-sheet encapsulants

NASA Astrophysics Data System (ADS)

Hara, Kohjiro; Ohwada, Hiroto; Furihata, Tomoyoshi; Masuda, Atsushi

2018-02-01

Crystalline Si photovoltaic (PV) modules were fabricated with sheets of poly(dimethylsiloxane) (silicone) as an encapsulant. The long-term durability of the silicone-encapsulated PV modules was experimentally investigated. The silicone-based modules enhanced the long-term durability against potential-induced degradation (PID) and a damp-heat (DH) condition at 85 °C with 85% relative humidity (RH). In addition, we designed and fabricated substrate-type Si PV modules based on the silicone encapsulant and an Al-alloy plate as the substratum, which demonstrated high impact resistance and high incombustible performance. The high chemical stability, high volume resistivity, rubber-like elasticity, and incombustibility of the silicone encapsulant resulted in the high durability of the modules. Our results indicate that silicone is an attractive encapsulation material, as it improves the long-term durability of crystalline Si PV modules.

Sequence-selective encapsulation and protection of long peptides by a self-assembled FeII8L6 cubic cage

NASA Astrophysics Data System (ADS)

Mosquera, Jesús; Szyszko, Bartosz; Ho, Sarah K. Y.; Nitschke, Jonathan R.

2017-03-01

Self-assembly offers a general strategy for the preparation of large, hollow high-symmetry structures. Although biological capsules, such as virus capsids, are capable of selectively recognizing complex cargoes, synthetic encapsulants have lacked the capability to specifically bind large and complex biomolecules. Here we describe a cubic host obtained from the self-assembly of FeII and a zinc-porphyrin-containing ligand. This cubic cage is flexible and compatible with aqueous media. Its selectivity of encapsulation is driven by the coordination of guest functional groups to the zinc porphyrins. This new host thus specifically encapsulates guests incorporating imidazole and thiazole moieties, including drugs and peptides. Once encapsulated, the reactivity of a peptide is dramatically altered: encapsulated peptides are protected from trypsin hydrolysis, whereas physicochemically similar peptides that do not bind are cleaved.

Encapsulation of probiotic bacteria with alginate-starch and evaluation of survival in simulated gastrointestinal conditions and in yoghurt.

PubMed

Sultana, K; Godward, G; Reynolds, N; Arumugaswamy, R; Peiris, P; Kailasapathy, K

2000-12-05

A modified method using calcium alginate for the microencapsulation of probiotic bacteria is reported in this study. Incorporation of Hi-Maize starch (a prebiotic) improved encapsulation of viable bacteria as compared to when the bacteria were encapsulated without the starch. Inclusion of glycerol (a cryo-protectant) with alginate mix increased the survival of bacteria when frozen at -20 degrees C. The acidification kinetics of encapsulated bacteria showed that the rate of acid produced was lower than that of free cultures. The encapsulated bacteria, however, did not demonstrate a significant increase in survival when subjected to in vitro high acid and bile salt conditions. A preliminary study was carried out in order to monitor the effects of encapsulation on the survival of Lactobacillus acidophilus and Bifidobacterium spp. in yoghurt over a period of 8 weeks. This study showed that the survival of encapsulated cultures of L. acidophilus and Bifidobacterium spp. showed a decline in viable count of about 0.5 log over a period of 8 weeks while there was a decline of about 1 log in cultures which were incorporated as free cells in yoghurt. The encapsulation method used in this study did not result in uniform bead size, and hence additional experiments need to be designed using uniform bead size in order to assess the role of different encapsulation parameters, such as bead size and alginate concentration, in providing protection to the bacteria.

Aerosol delivery of liposome-encapsulated ciprofloxacin: aerosol characterization and efficacy against Francisella tularensis infection in mice.

PubMed Central

Conley, J; Yang, H; Wilson, T; Blasetti, K; Di Ninno, V; Schnell, G; Wong, J P

1997-01-01

The aerosol delivery of liposome-encapsulated ciprofloxacin by using 12 commercially available jet nebulizers was evaluated in this study. Aerosol particles containing liposome-encapsulated ciprofloxacin generated by the nebulizers were analyzed with a laser aerodynamic particle sizer. Mean mass aerodynamic diameters (MMADs) and geometric standard deviations (GSDs) were determined, and the drug contents of the sampling filters from each run onto which aerosolized liposome-encapsulated ciprofloxacin had been deposited were analyzed spectrophotometrically. The aerosol particles of liposome-encapsulated ciprofloxacin generated by these nebulizers ranged from 1.94 to 3.5 microm, with GSDs ranging from 1.51 to 1.84 microm. The drug contents of the sampling filters exposed for 1 min to aerosolized liposome-encapsulated ciprofloxacin range from 12.7 to 40.5 microg/ml (0.06 to 0.2 mg/filter). By using the nebulizer selected on the basis of most desirable MMADs, particle counts, and drug deposition, aerosolized liposome-encapsulated ciprofloxacin was used for the treatment of mice infected with 10 times the 50% lethal dose of Francisella tularensis. All mice treated with aerosolized liposome-encapsulated ciprofloxacin survived the infection, while all ciprofloxacin-treated or untreated control mice succumbed to the infection (P < 0.001). These results suggest that aerosol delivery of liposome-encapsulated ciprofloxacin to the lower respiratory tract is feasible and that it may provide an effective therapy for the treatment of respiratory tract infections. PMID:9174185

Creating homogenous strain distribution within 3D cell-encapsulated constructs using a simple and cost-effective uniaxial tensile bioreactor: Design and validation study.

PubMed

Subramanian, Gayathri; Elsaadany, Mostafa; Bialorucki, Callan; Yildirim-Ayan, Eda

2017-08-01

Mechanical loading bioreactors capable of applying uniaxial tensile strains are emerging to be a valuable tool to investigate physiologically relevant cellular signaling pathways and biochemical expression. In this study, we have introduced a simple and cost-effective uniaxial tensile strain bioreactor for the application of precise and homogenous uniaxial strains to 3D cell-encapsulated collagen constructs at physiological loading strains (0-12%) and frequencies (0.01-1 Hz). The bioreactor employs silicone-based loading chambers specifically designed to stretch constructs without direct gripping to minimize stress concentration at the ends of the construct and preserve its integrity. The loading chambers are driven by a versatile stepper motor ball-screw actuation system to produce stretching of the constructs. Mechanical characterization of the bioreactor performed through Finite Element Analysis demonstrated that the constructs experienced predominantly uniaxial tensile strain in the longitudinal direction. The strains produced were found to be homogenous over a 15 × 4 × 2 mm region of the construct equivalent to around 60% of the effective region of characterization. The strain values were also shown to be consistent and reproducible during cyclic loading regimes. Biological characterization confirmed the ability of the bioreactor to promote cell viability, proliferation, and matrix organization of cell-encapsulated collagen constructs. This easy-to-use uniaxial tensile strain bioreactor can be employed for studying morphological, structural, and functional responses of cell-embedded matrix systems in response to physiological loading of musculoskeletal tissues. It also holds promise for tissue-engineered strategies that involve delivery of mechanically stimulated cells at the site of injury through a biological carrier to develop a clinically useful therapy for tissue healing. Biotechnol. Bioeng. 2017;114: 1878-1887. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Heparin/collagen encapsulating nerve growth factor multilayers coated aligned PLLA nanofibrous scaffolds for nerve tissue engineering.

PubMed

Zhang, Kuihua; Huang, Dianwu; Yan, Zhiyong; Wang, Chunyang

2017-07-01

Biomimicing topological structure of natural nerve tissue to direct axon growth and controlling sustained release of moderate neurotrophic factors are extremely propitious to the functional recovery of damaged nervous systems. In this study, the heparin/collagen encapsulating nerve growth factor (NGF) multilayers were coated onto the aligned poly-L-lactide (PLLA) nanofibrous scaffolds via a layer-by-layer (LbL) self-assembly technique to combine biomolecular signals, and physical guidance cues for peripheral nerve regeneration. Scanning electronic microscopy (SEM) revealed that the surface of aligned PLLA nanofibrous scaffolds coated with heparin/collagen multilayers became rougher and appeared some net-like filaments and protuberances in comparison with PLLA nanofibrous scaffolds. The heparin/collagen multilayers did not destroy the alignment of nanofibers. X-ray photoelectron spectroscopy and water contact angles displayed that heparin and collagen were successfully coated onto the aligned PLLA nanofibrous scaffolds and improved its hydrophilicity. Three-dimensional (3 D) confocal microscopy images further demonstrated that collagen, heparin, and NGF were not only coated onto the surface of aligned PLLA nanofibrous scaffolds but also permeated into the inner of scaffolds. Moreover, NGF presented a sustained release for 2 weeks from aligned nanofibrous scaffolds coated with 5.5 bilayers or above and remained good bioactivity. The heparin/collagen encapsulating NGF multilayers coated aligned nanofibrous scaffolds, in particular 5.5 bilayers or above, was more beneficial to Schwann cells (SCs) proliferation and PC12 cells differentiation as well as the SC cytoskeleton and neurite growth along the direction of nanofibrous alignment compared to the aligned PLLA nanofibrous scaffolds. This novel scaffolds combining sustained release of bioactive NGF and aligned nanofibrous topography presented an excellent potential in peripheral nerve regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1900-1910, 2017. © 2017 Wiley Periodicals, Inc.

Skin penetration and antioxidant effect of cosmeto-textiles with gallic acid.

PubMed

Alonso, C; Martí, M; Barba, C; Lis, M; Rubio, L; Coderch, L

2016-03-01

In this work, the antioxidant gallic acid (GA) has been encapsulated in microspheres prepared with poly-ε-caprolactone (PCL) and incorporated into polyamide (PA) obtaining the cosmeto-textile. The topical application of the cosmeto-textile provides a reservoir effect in the skin delivery of GA. The close contact of the cosmeto-textile, containing microsphere-encapsulated GA (ME-GA), with the skin and their corresponding occlusion, may be the main reasons that explain the crossing of active principle (GA) through the skin barrier, located in the stratum corneum, and its penetration into the different compartments of the skin, epidermis and dermis. An ex vivo assessment was performed to evaluate the antioxidant effect of the ME-GA on the stratum corneum (SC) using the thiobarbituric acid-reactive species (TBARS) test. The test is based on a non-invasive ex vivo methodology that evaluates lipid peroxides formed in the outermost layers of the SC from human volunteers after UV radiation to determine the effectiveness of an antioxidant. In this case, a ME-GA cosmeto-textile or ME-GA formulation were applied to the skin in vivo and lipid peroxidation (LPO) in the horny layer were determined after UV irradiation. This methodology may be used as a quality control tool to determine ex vivo the percentage of LPO inhibition on human SC for a variety of antioxidants that are topically applied, in this case GA. Results show that LPO formation was inhibited in human SC when GA was applied directly or embedded in the cosmeto-textile, demonstrating the effectiveness of both applications. The percentage of LPO inhibition obtained after both topical applications was approximately 10% for the cosmeto-textile and 41% for the direct application of microspheres containing GA. This methodology could be used to determine the effectiveness of topically applied antioxidants encapsulated in cosmeto-textiles on human SC. Copyright © 2016 Elsevier B.V. All rights reserved.

Encapsulation methods for organic electrical devices

DOEpatents

Blum, Yigal D.; Chu, William Siu-Keung; MacQueen, David Brent; Shi, Yijian

2013-06-18

The disclosure provides methods and materials suitable for use as encapsulation barriers in electronic devices. In one embodiment, for example, there is provided an electroluminescent device or other electronic device encapsulated by alternating layers of a silicon-containing bonding material and a ceramic material. The encapsulation methods provide, for example, electronic devices with increased stability and shelf-life. The invention is useful, for example, in the field of microelectronic devices.

Transferrin-Conjugated SNALPs Encapsulating 2′-O-Methylated miR-34a for the Treatment of Multiple Myeloma

PubMed Central

Scognamiglio, Immacolata; Di Martino, Maria Teresa; Campani, Virginia; Virgilio, Antonella; Galeone, Aldo; Gullà, Annamaria; Gallo Cantafio, Maria Eugenia; Tagliaferri, Pierosandro; Tassone, Pierfrancesco; Caraglia, Michele

2014-01-01

Stable nucleic acid lipid vesicles (SNALPs) encapsulating miR-34a to treat multiple myeloma (MM) were developed. Wild type or completely 2′-O-methylated (OMet) MiR-34a was used in this study. Moreover, SNALPs were conjugated with transferrin (Tf) in order to target MM cells overexpressing transferrin receptors (TfRs). The type of miR-34a chemical backbone did not significantly affect the characteristics of SNALPs in terms of mean size, polydispersity index, and zeta potential, while the encapsulation of an OMet miR-34a resulted in a significant increase of miRNA encapsulation into the SNALPs. On the other hand, the chemical conjugation of SNALPs with Tf resulted in a significant decrease of the zeta potential, while size characteristics and miR-34a encapsulation into SNALPs were not significantly affected. In an experimental model of MM, all the animals treated with SNALPs encapsulating miR-34a showed a significant inhibition of the tumor growth. However, the use of SNALPs conjugated with Tf and encapsulating OMet miR-34a resulted in the highest increase of mice survival. These results may represent the proof of concept for the use of SNALPs encapsulating miR-34a for the treatment of MM. PMID:24683542

Using ß-cyclodextrin and Arabic Gum as Wall Materials for Encapsulation of Saffron Essential Oil

PubMed Central

Atefi, Mohsen; Nayebzadeh, Kooshan; Mohammadi, Abdorreza; Mortazavian, Amir Mohammad

2017-01-01

Saffron essential oil has a pleasant aroma and medicinal activities. However, it is sensible into the environmental condition. Therefore, it should be protected against unwanted changes during storage or processing. Encapsulation is introduced as a process by which liable materials are protected from unwanted changes. In the present study, different ratios (0:100, 25:75, 50:50, 75:25, and 100:0) of ß-cyclodextrin (ß-CD) and arabic gum (GA) were used as wall martial for encapsulation saffron essential oil. In order to calculate of loading capacity (LC) and encapsulation efficiency (EE), and release (RE), safranal was determined as indicator of saffron essential oil using GC. According to the results, the highest LC and EE were related to the mixture of ß-CD/GA at a 75:25 ratio. In contrast, the lowest encapsulate hygroscopicity (EH) and RE were observed when only ß-CD was applied as wall material (P≤0.05). Comparing the differential scanning calorimetry (DSC) thermograms of the control and encapsulate of ß-CD/GA (75:25) confirmed encapsulation of saffron essential oil. Scanning electron microscopy (SEM) images with high magnifications showed the rhombic structure that partially coated by GA. The mixture of ß-CD/GA at a 75:25 ratio can be recommended for saffron essential oil encapsulation. PMID:28496464

Influence of silica matrix composition and functional component additives on the bioactivity and viability of encapsulated living cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Travis J.; Dunphy, Darren R.; Harbaugh, Svetlana

The remarkable impact encapsulation matrix chemistry can have on the bioactivity and viability of integrated living cells is reported. Two silica chemistries (aqueous silicate and alkoxysilane), and a functional component additive (glycerol), are employed to generate three distinct silica matrices. These matrices are used to encapsulate living E. coli cells engineered with a synthetic riboswitch for cell-based biosensing. Following encapsulation, membrane integrity, reproductive capability, and riboswitch-based protein expression levels and rates are measured over a 5 week period. Striking differences in E. coli bioactivity, viability, and biosensing performance are observed for cells encapsulated within the different matrices. E. coli cellsmore » encapsulated for 35 days in aqueous silicate-based (AqS) matrices showed relatively low membrane integrity, but high reproductive capability in comparison to cells encapsulated in glycerol containing sodium silicate-based (AqS + g) and alkoxysilane-based (PGS) gels. Further, cells in sodium silicate-based matrices showed increasing fluorescence output over time, resulting in a 1.8-fold higher fluorescence level, and a faster expression rate, over cells free in solution. Furthermore, this unusual and unique combination of biological properties demonstrates that careful design of the encapsulation matrix chemistry can improve functionality of the biocomposite material, and result in new and unexpected physiological states.« less

Examining the Roles of Emulsion Droplet Size and Surfactant in the Interfacial Instability-Based Fabrication Process of Micellar Nanocrystals

NASA Astrophysics Data System (ADS)

Sun, Yuxiang; Mei, Ling; Han, Ning; Ding, Xinyi; Yu, Caihao; Yang, Wenjuan; Ruan, Gang

2017-06-01

The interfacial instability process is an emerging general method to fabricate nanocrystal-encapsulated micelles (also called micellar nanocrystals) for biological detection, imaging, and therapy. The present work utilized fluorescent semiconductor nanocrystals (quantum dots or QDs) as the model nanocrystals to investigate the interfacial instability-based fabrication process of nanocrystal-encapsulated micelles. Our experimental results suggest intricate and intertwined roles of the emulsion droplet size and the surfactant poly (vinyl alcohol) (PVA) used in the fabrication process of QD-encapsulated poly (styrene-b-ethylene glycol) (PS-PEG) micelles. When no PVA is used, no emulsion droplet and thus no micelle is successfully formed; Emulsion droplets with large sizes ( 25 μm) result in two types of QD-encapsulated micelles, one of which is colloidally stable QD-encapsulated PS-PEG micelles while the other of which is colloidally unstable QD-encapsulated PVA micelles; In contrast, emulsion droplets with small sizes ( 3 μm or smaller) result in only colloidally stable QD-encapsulated PS-PEG micelles. The results obtained in this work not only help to optimize the quality of nanocrystal-encapsulated micelles prepared by the interfacial instability method for biological applications but also offer helpful new knowledge on the interfacial instability process in particular and self-assembly in general.

Encapsulation of biomaterials in porous glass-like matrices prepared via an aqueous colloidal sol-gel process

DOEpatents

Liu, Dean-Mo; Chen, I-Wei

2001-01-01

The present invention provides a process for the encapsulation of biologically important proteins into transparent, porous silica matrices by an alcohol-free, aqueous, colloidal sol-gel process, and to the biological materials encapsulated thereby. The process is exemplified by studies involving encapsulated cytochrome c, catalase, myoglobin, and hemoglobin, although non-proteinaceous biomaterials, such as active DNA or RNA fragments, cells or even tissues, may also be encapsulated in accordance with the present methods. Conformation, and hence activity of the biomaterial, is successfully retained after encapsulation as demonstrated by optical characterization of the molecules, even after long-term storage. The retained conformation of the biomaterial is strongly correlated to both the rate of gelation and the subsequent drying speed of the encapsulatng matrix. Moreover, in accordance with this process, gelation is accelerated by the use of a higher colloidal solid concentration and a lower synthesis pH than conventional methods, thereby enhancing structural stability and retained conformation of the biomaterials. Thus, the invention also provides a remarkable improvement in retaining the biological activity of the encapsulated biomaterial, as compared with those involved in conventional alkoxide-based processes. It further provides new methods for the quantitative and qualitative detection of test substances that are reactive to, or catalyzed by, the active, encapsulated biological materials.

Defect and Ordered Tungsten Oxides Encapsulated Inside 2H-W X2( X=S and Se) Fullerene-Related Structures

NASA Astrophysics Data System (ADS)

Sloan, Jeremy; Hutchison, John L.; Tenne, Reshef; Feldman, Yishay; Tsirlina, Tatyana; Homyonfer, Moshe

1999-04-01

Complex tungsten oxides, consisting of nonstoichiometric oxides of the form WO3-xand stoichiometric lamellar oxides of the form {001}RWnO3n-1(n=3 to 6) have been observed incorporated within 2H-WX2(X=S or Se) inorganic fullerene-like (IF) structures by HRTEM. These encapsulates were formed from a gas-solid reaction between H2Xand disordered WO3-xprecursors exhibiting a range of particle sizes and morphologies. The microstructures of most of the encapsulated oxides could be described in terms of {hkl}Rcrystallographic shear (CS) structures formed relative to an ReO3-type (R) substructure. Smaller spheroidal WO3-xencapsulates were frequently found to exhibit random {103}RCS defects of the Wadsley type, while larger, needle encapsulates were found to form exclusively {001}RWnO3n-1type lamellar structures that were predominantely ordered. Spheriodal encapsulates with randomly spaced {001}RCS planes were also observed encapsulated inside 2H-WSe2IF structures. The growth and morphologies of the encapsulating 2H-WX2shells were profoundly influenced by those of the precursor oxides used in their formation. Ordering mechanisms were proposed with respect to the formation of the ordered encapsulated oxides from the disordered precursors.

Influence of silica matrix composition and functional component additives on the bioactivity and viability of encapsulated living cells

DOE PAGES

Savage, Travis J.; Dunphy, Darren R.; Harbaugh, Svetlana; ...

2015-11-06

The remarkable impact encapsulation matrix chemistry can have on the bioactivity and viability of integrated living cells is reported. Two silica chemistries (aqueous silicate and alkoxysilane), and a functional component additive (glycerol), are employed to generate three distinct silica matrices. These matrices are used to encapsulate living E. coli cells engineered with a synthetic riboswitch for cell-based biosensing. Following encapsulation, membrane integrity, reproductive capability, and riboswitch-based protein expression levels and rates are measured over a 5 week period. Striking differences in E. coli bioactivity, viability, and biosensing performance are observed for cells encapsulated within the different matrices. E. coli cellsmore » encapsulated for 35 days in aqueous silicate-based (AqS) matrices showed relatively low membrane integrity, but high reproductive capability in comparison to cells encapsulated in glycerol containing sodium silicate-based (AqS + g) and alkoxysilane-based (PGS) gels. Further, cells in sodium silicate-based matrices showed increasing fluorescence output over time, resulting in a 1.8-fold higher fluorescence level, and a faster expression rate, over cells free in solution. Furthermore, this unusual and unique combination of biological properties demonstrates that careful design of the encapsulation matrix chemistry can improve functionality of the biocomposite material, and result in new and unexpected physiological states.« less

Using ß-cyclodextrin and Arabic Gum as Wall Materials for Encapsulation of Saffron Essential Oil.

PubMed

Atefi, Mohsen; Nayebzadeh, Kooshan; Mohammadi, Abdorreza; Mortazavian, Amir Mohammad

2017-01-01

Saffron essential oil has a pleasant aroma and medicinal activities. However, it is sensible into the environmental condition. Therefore, it should be protected against unwanted changes during storage or processing. Encapsulation is introduced as a process by which liable materials are protected from unwanted changes. In the present study, different ratios (0:100, 25:75, 50:50, 75:25, and 100:0) of ß-cyclodextrin (ß-CD) and arabic gum (GA) were used as wall martial for encapsulation saffron essential oil. In order to calculate of loading capacity (LC) and encapsulation efficiency (EE), and release (RE), safranal was determined as indicator of saffron essential oil using GC. According to the results, the highest LC and EE were related to the mixture of ß-CD/GA at a 75:25 ratio. In contrast, the lowest encapsulate hygroscopicity (EH) and RE were observed when only ß-CD was applied as wall material (P≤0.05). Comparing the differential scanning calorimetry (DSC) thermograms of the control and encapsulate of ß-CD/GA (75:25) confirmed encapsulation of saffron essential oil. Scanning electron microscopy (SEM) images with high magnifications showed the rhombic structure that partially coated by GA. The mixture of ß-CD/GA at a 75:25 ratio can be recommended for saffron essential oil encapsulation.

Optimisation of stability and charge transferability of ferrocene-encapsulated carbon nanotubes

NASA Astrophysics Data System (ADS)

Prajongtat, Pongthep; Sriyab, Suwannee; Zentgraf, Thomas; Hannongbua, Supa

2018-01-01

Ferrocene-encapsulated carbon nanotubes (Fc@CNTs) became promising nanocomposite materials for a wide range of applications due to their superior catalytic, mechanical and electronic properties. To open up new windows of applications, the highly stable and charge transferable encapsulation complexes are required. In this work, we designed the new encapsulation complexes formed from ferrocene derivatives (FcR, where R = -CHO, -CH2OH, -CON3 and -PCl2) and single-walled carbon nanotubes (SWCNTs). The influence of diameter and chirality of the nanotubes on the stability, charge transferability and electronic properties of such complexes has been investigated using density functional theory. The calculations suggest that the encapsulation stability and charge transferability of the encapsulation complexes depend on the size and chirality of the nanotubes. FcR@SWCNTs are more stable than Fc@SWCNTs at the optimum tube diameter. The greatest charge transfer was observed for FcCH2OH@SWCNTs and Fc@SWCNTs since the Fe d levels of FcCH2OH and Fc are nearly equal and close to the Fermi energy level of the nanotubes. The obtained results pave the way to the design of new encapsulated ferrocene derivatives which can give rise to higher stability and charge transferability of the encapsulation complexes.

In Vivo Tumor Vasculature Targeting of CuS@MSN Based Theranostic Nanomedicine.

PubMed

Chen, Feng; Hong, Hao; Goel, Shreya; Graves, Stephen A; Orbay, Hakan; Ehlerding, Emily B; Shi, Sixiang; Theuer, Charles P; Nickles, Robert J; Cai, Weibo

2015-01-01

Actively targeted theranostic nanomedicine may be the key for future personalized cancer management. Although numerous types of theranostic nanoparticles have been developed in the past decade for cancer treatment, challenges still exist in the engineering of biocompatible theranostic nanoparticles with highly specific in vivo tumor targeting capabilities. Here, we report the design, synthesis, surface engineering, and in vivo active vasculature targeting of a new category of theranostic nanoparticle for future cancer management. Water-soluble photothermally sensitive copper sulfide nanoparticles were encapsulated in biocompatible mesoporous silica shells, followed by multistep surface engineering to form the final theranostic nanoparticles. Systematic in vitro targeting, an in vivo long-term toxicity study, photothermal ablation evaluation, in vivo vasculature targeted imaging, biodistribution and histology studies were performed to fully explore the potential of as-developed new theranostic nanoparticles.

Drift study of SU8 cantilevers in liquid and gaseous environments.

PubMed

Tenje, Maria; Keller, Stephan; Dohn, Søren; Davis, Zachary J; Boisen, Anja

2010-05-01

We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum.

Analysis of the aging/stability process of organic solar cells based on PTB7:[70]PCBM and an alternative free-vacuum deposited cathode: the effect of active layer scaling

NASA Astrophysics Data System (ADS)

Barreiro-Argüelles, Denisse; Ramos-Ortiz, Gabriel; Maldonado, José-Luis L.; Romero-Borja, Daniel; Meneses-Nava, Marco-Antonio; Pérez-Gutiérrez, Enrique

2017-08-01

The PV performance and aging/stability of organic photovoltaic (OPV) devices based on the well-known system PTB7:[70]PCBM and an alternative air-stable electrode deposited at room conditions are fully studied when the active area is scaled by a factor of 25. On the other hand, the aging/stability processes were also studied through single diode model, impedance spectroscopy and light-beam induced current (LBIC) measurements in accordance with the established ISOS-D1 (dark storage) and ISOS-L1 (illumination conditions) protocols. Results are a good indication that the alternative cathode Field's metal (FM) cathode works as an encapsulating material and provides excellent PV performance comparable with the common and costly high-vacuum evaporated Al cathode.

Attempts at a numerical realisation of stochastic differential equations containing Preisach operator

NASA Astrophysics Data System (ADS)

McCarthy, S.; Rachinskii, D.

2011-01-01

We describe two Euler type numerical schemes obtained by discretisation of a stochastic differential equation which contains the Preisach memory operator. Equations of this type are of interest in areas such as macroeconomics and terrestrial hydrology where deterministic models containing the Preisach operator have been developed but do not fully encapsulate stochastic aspects of the area. A simple price dynamics model is presented as one motivating example for our studies. Some numerical evidence is given that the two numerical schemes converge to the same limit as the time step decreases. We show that the Preisach term introduces a damping effect which increases on the parts of the trajectory demonstrating a stronger upwards or downwards trend. The results are preliminary to a broader programme of research of stochastic differential equations with the Preisach hysteresis operator.

[Workplace health promotion in public health policies in Poland].

PubMed

Puchalski, Krzysztof; Korzeniowska, Elzbieta

2008-01-01

In this paper the author analyses how far in Poland the idea of workplace health promotion (WHP) does exist in the area of public health understood in its broadest sense. The analysis encapsulates the following issues: (a) the national legislative policy, (b) strategies, programs and projects concerning health issues launched or coordinated by the state or local administration, (c) grassroots initiatives for health promotion supported by local and regional administration, (d) civic projects or business strategies for health. In addition, the author emphasizes the marginalization of workplace health promotion and lack of cohesive policy in this field as well as, the fact that health problems of the working population arising from current demographic, technological, economic and social changes that could be dealt with through developing and implementing WHP projects are not yet fully perceived by public health policy makers.

Effects of melamine formaldehyde resin and CaCO3 diffuser-loaded encapsulation on correlated color temperature uniformity of phosphor-converted LEDs.

PubMed

Yang, Liang; Lv, Zhicheng; Jiaojiao, Yuan; Liu, Sheng

2013-08-01

Phosphor-free dispensing is the most widely used LED packaging method, but this method results in poor quality in angular CCT uniformity. This study proposes a diffuser-loaded encapsulation to solve the problem; the effects of melamine formaldehyde (MF) resin and CaCO3 loaded encapsulation on correlated color temperature (CCT) uniformity and luminous efficiency reduction of the phosphor-converted LEDs are investigated. Results reveal that MF resin loaded encapsulation has better light diffusion performance compared to MF resin loaded encapsulation at the same diffuser concentration, but CaCO3 loaded encapsulation has better luminous efficiency maintenance. The improvements in angular color uniformity for the LEDs emitting with MF resin and CaCO3 loaded encapsulation can be explained by the increase in photon scattering. The utility of this low cost and controllable mineral diffuser packaging method provides a practical approach for enhancing the angular color uniformity of LEDs. The diffuser mass ratio of 1% MF resin or 10% CaCO3 is the optimum condition to obtain low angular CCT variance and high luminous efficiency.

Stability Analysis of an Encapsulated Microbubble against Gas Diffusion

PubMed Central

Katiyar, Amit; Sarkar, Kausik

2009-01-01

Linear stability analysis is performed for a mathematical model of diffusion of gases from an encapsulated microbubble. It is an Epstein-Plesset model modified to account for encapsulation elasticity and finite gas permeability. Although, bubbles, containing gases other than air is considered, the final stable bubble, if any, contains only air, and stability is achieved only when the surrounding medium is saturated or oversaturated with air. In absence of encapsulation elasticity, only a neutral stability is achieved for zero surface tension, the other solution being unstable. For an elastic encapsulation, different equilibrium solutions are obtained depending on the saturation level and whether the surface tension is smaller or higher than the elasticity. For an elastic encapsulation, elasticity can stabilize the bubble. However, imposing a non-negativity condition on the effective surface tension (consisting of reference surface tension and the elastic stress) leads to an equilibrium radius which is only neutrally stable. If the encapsulation can support net compressive stress, it achieves actual stability. The linear stability results are consistent with our recent numerical findings. Physical mechanisms for the stability or instability of various equilibriums are provided. PMID:20005522

Cellulosic fabrics printing with multifunctional encapsulated phthalocyanine pigment blue using phase separation method.

PubMed

Haroun, Ahmed A; Diab, H A; Hakeim, O A

2016-08-01

Aqueous dispersions of citric-acrylate (CAC) oligomer encapsulating C.I. Pigment Blue 15:3 (PB15:3) in the presence of glutaraldhyde were formulated using the phase separation method. FT-IR spectroscopy and centrifuge sedimentation are performed to confirm the encapsulation of pigment into CAC oligomer. The prepared capsules were characterized using thermal gravimetric analysis (TGA) and transmission electron microscope (TEM). The results revealed that the encapsulated pigment had a profound multifunctional impact and minimized the driving force of pigment printing on the cellulosic fabrics. Besides, the encapsulated pigment accelerated the pigment fixation on cellulosic fabrics without drying in one step and reduced the required amount of the binder, compared with the control sample. Furthermore, the printed fabrics exhibited good antibacterial performance against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The presence of the crosslinker could be stabilized the encapsulated pigment on the cellulosic fabrics. Moreover, the light and washing fastness for the printed fabrics using encapsulated pigment are higher than that in case of using control samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of DBD plasma actuators: The double encapsulated electrode

NASA Astrophysics Data System (ADS)

Erfani, Rasool; Zare-Behtash, Hossein; Hale, Craig; Kontis, Konstantinos

2015-04-01

Plasma actuators are electrical devices that generate a wall bounded jet without the use of any moving parts. For aerodynamic applications they can be used as flow control devices to delay separation and augment lift on a wing. The standard plasma actuator consists of a single encapsulated (ground) electrode. The aim of this project is to investigate the effect of varying the number and distribution of encapsulated electrodes in the dielectric layer. Utilising a transformer cascade, a variety of input voltages are studied for their effect. In the quiescent environment of a Faraday cage the velocity flow field is recorded using particle image velocimetry. Through understanding of the mechanisms involved in producing the wall jet and the importance of the encapsulated electrode a novel actuator design is proposed. The actuator design distributes the encapsulated electrode throughout the dielectric layer. The experiments have shown that actuators with a shallow initial encapsulated electrode induce velocities greater than the baseline case at the same voltage. Actuators with a deep initial encapsulated electrode are able to induce the highest velocities as they can operate at higher voltages without breakdown of the dielectric.

Low Hysteresis Carbon Nanotube Transistors Constructed via a General Dry-Laminating Encapsulation Method on Diverse Surfaces.

PubMed

Yang, Yi; Wang, Zhongwu; Xu, Zeyang; Wu, Kunjie; Yu, Xiaoqin; Chen, Xiaosong; Meng, Yancheng; Li, Hongwei; Qiu, Song; Jin, Hehua; Li, Liqiang; Li, Qingwen

2017-04-26

Electrical hysteresis in carbon nanotube thin-film transistor (CNTTFT) due to surface adsorption of H 2 O/O 2 is a severe obstacle for practical applications. The conventional encapsulation methods based on vacuum-deposited inorganic materials or wet-coated organic materials have some limitations. In this work, we develop a general and highly efficient dry-laminating encapsulation method to reduce the hysteresis of CNTTFTs, which may simultaneously realize the construction and encapsulation of CNTTFT. Furthermore, by virtue of dry procedure and wide compatibility of PMMA, this method is suitable for the construction of CNTTFT on diverse surface including both inorganic and organic dielectric materials. Significantly, the dry-encapsulated CNTTFT exhibits very low or even negligible hysteresis with good repeatability and air stability, which is greatly superior to the nonencapsulated and wet-encapsulated CNTTFT with spin-coated PMMA. The dry-laminating encapsulation strategy, a kind of technological innovation, resolves a significant problem of CNTTFT and therefore will be promising in facile transferring and packaging the CNT films for high-performance optoelectronic devices.

Germanium detector vacuum encapsulation

NASA Technical Reports Server (NTRS)

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Flame Suppression Agent, System and Uses

NASA Technical Reports Server (NTRS)

Parrish, Clyde F. (Inventor)

2013-01-01

Aqueous droplets encapsulated in a flame retardant polymer are useful in suppressing combustion. Upon exposure to a flame, the encapsulated aqueous droplets rupture and vaporize, removing heat and displacing oxygen to retard the combustion process. The polymer encapsulant, through decomposition, may further add free radicals to the combustion atmosphere, thereby further retarding the combustion process. The encapsulated aqueous droplets may be used as a replacement to halon, water mist and dry powder flame suppression systems.

One-to-one encapsulation based on alternating droplet generation

NASA Astrophysics Data System (ADS)

Hirama, Hirotada; Torii, Toru

2015-10-01

This paper reports the preparation of encapsulated particles as models of cells using an alternating droplet generation encapsulation method in which the number of particles in a droplet is controlled by a microchannel to achieve one-to-one encapsulation. Using a microchannel in which wettability is treated locally, the fluorescent particles used as models of cells were successfully encapsulated in uniform water-in-oil-in-water (W/O/W) emulsion droplets. Furthermore, 20% of the particle-containing droplets contained one particle. Additionally, when a surfactant with the appropriate properties was used, the fluorescent particles within each inner aqueous droplet were enclosed in the merged droplet by spontaneous droplet coalescence. This one-to-one encapsulation method based on alternating droplet generation could be used for a variety of applications, such as high-throughput single-cell assays, gene transfection into cells or one-to-one cell fusion.

One-to-one encapsulation based on alternating droplet generation.

PubMed

Hirama, Hirotada; Torii, Toru

2015-10-21

This paper reports the preparation of encapsulated particles as models of cells using an alternating droplet generation encapsulation method in which the number of particles in a droplet is controlled by a microchannel to achieve one-to-one encapsulation. Using a microchannel in which wettability is treated locally, the fluorescent particles used as models of cells were successfully encapsulated in uniform water-in-oil-in-water (W/O/W) emulsion droplets. Furthermore, 20% of the particle-containing droplets contained one particle. Additionally, when a surfactant with the appropriate properties was used, the fluorescent particles within each inner aqueous droplet were enclosed in the merged droplet by spontaneous droplet coalescence. This one-to-one encapsulation method based on alternating droplet generation could be used for a variety of applications, such as high-throughput single-cell assays, gene transfection into cells or one-to-one cell fusion.

Preparation of a novel composite nanofiber gel-encapsulated human placental extract through layer-by-layer self-assembly

PubMed Central

LIU, GUOHUI; CHEN, XI; ZHOU, WU; YANG, SHUHUA; YE, SHUNAN; CAO, FAQI; LIU, YI; XIONG, YUAN

2016-01-01

Aqueous human placenta extract (HPE) has been previously used to treat chronic soft tissue ulcer; however, the optimal dosage of HPE has yet to be elucidated. The present study investigated a novel nanofiber gel composed through layer-by-layer (LbL) self-assembly, in which HPE was encapsulated. IKVAV, RGD, RAD16 and FGL-PA were screened and combined to produce an optimal vehicle nanofiber gel through LbL assembly. Subsequently, the aqueous HPE was encapsulated into this nanofiber at the appropriate concentration, and the morphology, particle size, drug loading efficacy, encapsulation rate, release efficiency and structure validation were detected. The encapsulation efficiency of all three HPE samples was >90%, the nanofiber gel exhibited a slow releasing profile, and the structure of HPE encapsulated in the nanofiber gel was unvaried. In conclusion, this type of novel composite nanocapsules may offer a promising delivery system for HPE. PMID:27073463

High-Performance CCSDS Encapsulation Service Implementation in FPGA

NASA Technical Reports Server (NTRS)

Clare, Loren P.; Torgerson, Jordan L.; Pang, Jackson

2010-01-01

The Consultative Committee for Space Data Systems (CCSDS) Encapsulation Service is a convergence layer between lower-layer space data link framing protocols, such as CCSDS Advanced Orbiting System (AOS), and higher-layer networking protocols, such as CFDP (CCSDS File Delivery Protocol) and Internet Protocol Extension (IPE). CCSDS Encapsulation Service is considered part of the data link layer. The CCSDS AOS implementation is described in the preceding article. Recent advancement in RF modem technology has allowed multi-megabit transmission over space links. With this increase in data rate, the CCSDS Encapsulation Service needs to be optimized to both reduce energy consumption and operate at a high rate. CCSDS Encapsulation Service has been implemented as an intellectual property core so that the aforementioned problems are solved by way of operating the CCSDS Encapsulation Service inside an FPGA. The CCSDS En capsula tion Service in FPGA implementation consists of both packetizing and de-packetizing features

Limonene encapsulation in freeze dried gellan systems.

PubMed

Evageliou, Vasiliki; Saliari, Dimitra

2017-05-15

The encapsulation of limonene in freeze-dried gellan systems was investigated. Surface and encapsulated limonene content was determined by measurement of the absorbance at 252nm. Gellan matrices were both gels and solutions. For a standard gellan concentration (0.5wt%) gelation was induced by potassium or calcium chloride. Furthermore, gellan solutions of varying concentrations (0.25-1wt%) were also studied. Limonene was added at two different concentrations (1 and 2mL/100g sample). Gellan gels encapsulated greater amounts of limonene than solutions. Among all gellan gels, the KCl gels had the greater encapsulated limonene content. However, when the concentration of limonene was doubled in these KCl gels, the encapsulated limonene decreased. The surface limonene content was significant, especially for gellan solutions. The experimental conditions and not the mechanical properties of the matrices were the dominant factor in the interpretation of the observed results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Encapsulation efficacy of natural and synthetic photosensitizers by silica nanoparticles for photodynamic applications.

PubMed

Makhadmeh, Ghaseb Naser; Abdul Aziz, Azlan; Abdul Razak, Khairunisak; Abu Noqta, Osama

2015-12-01

This study analysed the physical effects of Cichorium Pumilum (CP), as a natural photosensitizer (PS), and Protoporphyrin IX (PpIX), as a synthetic PS, encapsulated with silica nanoparticles (SiNPs) in photodynamic therapy. The optimum concentrations of CP and PpIX, needed to destroy Red Blood Cells (RBC), were determined and the efficacy of encapsulated CP and PpIX were compared with naked CP and PpIX was verified. The results confirmed the applicability of CP and PpIX encapsulated in SiNPs on RBCs, and established a relationship between the encapsulated CP and PpIX concentration and the time required to rupture 50% of the RBCs (t50). The CP and PpIX encapsulated in SiNPs exhibited higher efficacy compared with that of naked CP and PpIX, respectively, and CP had less efficacy compared with PpIX.

Alginate-encapsulation of shoot tips of jojoba [Simmondsia chinensis (Link) Schneider] for germplasm exchange and distribution.

PubMed

Kumar, Sunil; Rai, Manoj K; Singh, Narender; Mangal, Manisha

2010-12-01

Shoot tips excised from in vitro proliferated shoots derived from nodal explants of jojoba [Simmondsia chinensis (Link) Schneider] were encapsulated in calcium alginate beads for germplasm exchange and distribution. A gelling matrix of 3 % sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Best response for shoot sprouting from encapsulated shoot tips was recorded on 0.8 % agar-solidified full-strength MS medium. Rooting was induced upon transfer of sprouted shoots to 0.8 % agar-solidified MS medium containing 1 mg l(-1) IBA. About 70 % of encapsulated shoot tips were rooted and converted into plantlets. Plants regenerated from encapsulated shoot tips were acclimatized successfully. The present encapsulation approach could also be applied as an alternative method of propagation of desirable elite genotype of jojoba.

Vibrational spectroscopy and imaging for concurrent cellular trafficking of co-localized doxorubicin and deuterated phospholipid vesicles

NASA Astrophysics Data System (ADS)

Misra, S. K.; Mukherjee, P.; Ohoka, A.; Schwartz-Duval, A. S.; Tiwari, S.; Bhargava, R.; Pan, D.

2016-01-01

Simultaneous tracking of nanoparticles and encapsulated payload is of great importance and visualizing their activity is arduous. Here we use vibrational spectroscopy to study the in vitro tracking of co-localized lipid nanoparticles and encapsulated drug employing a model system derived from doxorubicin-encapsulated deuterated phospholipid (dodecyl phosphocholine-d38) single tailed phospholipid vesicles.Simultaneous tracking of nanoparticles and encapsulated payload is of great importance and visualizing their activity is arduous. Here we use vibrational spectroscopy to study the in vitro tracking of co-localized lipid nanoparticles and encapsulated drug employing a model system derived from doxorubicin-encapsulated deuterated phospholipid (dodecyl phosphocholine-d38) single tailed phospholipid vesicles. Electronic supplementary information (ESI) available: Raman and confocal images of the Deuto-DOX-NPs in cells, materials and details of methods. See DOI: 10.1039/c5nr07975f

Hydrogel design of experiments methodology to optimize hydrogel for iPSC-NPC culture.

PubMed

Lam, Jonathan; Carmichael, S Thomas; Lowry, William E; Segura, Tatiana

2015-03-11

Bioactive signals can be incorporated in hydrogels to direct encapsulated cell behavior. Design of experiments methodology methodically varies the signals systematically to determine the individual and combinatorial effects of each factor on cell activity. Using this approach enables the optimization of three ligands concentrations (RGD, YIGSR, IKVAV) for the survival and differentiation of neural progenitor cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frequency regulator for synchronous generators

DOEpatents

Karlicek, R.F.

1982-08-10

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices. 11 figs.

Magnetic nanoparticles: Applications in gene delivery and gene therapy.

PubMed

Majidi, Sima; Zeinali Sehrig, Fatemeh; Samiei, Mohammad; Milani, Morteza; Abbasi, Elham; Dadashzadeh, Kianoosh; Akbarzadeh, Abolfazl

2016-06-01

Gene therapy is defined as the direct transfer of genetic material to tissues or cells for the treatment of inherited disorders and acquired diseases. For gene delivery, magnetic nanoparticles (MNPs) are typically combined with a delivery platform to encapsulate the gene, and promote cell uptake. Delivery technologies that have been used with MNPs contain polymeric, viral, as well as non-viral platforms. In this review, we focus on targeted gene delivery using MNPs.

Thermogelling 3D Systems towards Stem Cell-Based Tissue Regeneration Therapies.

PubMed

Wang, Xiaoyuan; Young, David James; Wu, Yun-Long; Loh, Xian Jun

2018-03-02

Stem cell culturing and differentiation is a very important research direction for tissue engineering. Thermogels are well suited for encapsulating cells because of their non-biotoxic nature and mild sol-gel transition as temperature increases. In particular, thermogels provide a 3D growth environment for stem cell growth, which is more similar to the extracellular matrix than flat substrates, so thermogels as a medium can overcome many of the cell abnormalities caused by 2D cell growth. In this review, we summarize the applications of thermogels in cell and stem cell culture in recent years. We also elaborate on the methods to induce stem cell differentiation by using thermogel-based 3D scaffolds. In particular, thermogels, encapsulating specific differentiation-inducing factor and having specific structures and moduli, can induce the differentiation into the desired tissue cells. Three dimensional thermogel scaffolds that control the growth and differentiation of cells will undoubtedly have a bright future in regenerative medicine.

Discovery, development, and clinical application of sugammadex sodium, a selective relaxant binding agent

PubMed Central

Welliver, Mark; McDonough, John; Kalynych, Nicholas; Redfern, Robert

2008-01-01

Neuromuscular blockade, induced by neuromuscular blocking agents, has allowed prescribed immobility, improved surgical exposure, optimal airway management conditions, and facilitated mechanical ventilation. However, termination of the effects of neuromuscular blocking agents has, until now, remained limited. A novel cyclodextrin encapsulation process offers improved termination of the paralytic effects of aminosteroidal non-depolarizing neuromuscular blocking agents. Sugammadex sodium is the first in a new class of drug called selective relaxant binding agents. Currently, in clinical trials, sugammadex, a modified gamma cyclodextrin, has shown consistent and rapid termination of neuromuscular blockade with few side effects. The pharmacology of cyclodextrins in general and sugammadex in particular, together with the results of current clinical research are reviewed. The ability of sugammadex to terminate the action of neuromuscular blocking agents by direct encapsulation is compared to the indirect competitive antagonism of their effects by cholinesterase inhibitors. Also discussed are the clinical implications that extend beyond fast, effective reversal, including numerous potential perioperative benefits. PMID:19920893

Fluoride ion encapsulation by Mg2+ and phosphates in a fluoride riboswitch

PubMed Central

Ren, Aiming; Rajashankar, Kanagalaghatta R.; Patel, Dinshaw J.

2012-01-01

Significant advances in our understanding of RNA architecture, folding and recognition have emerged from structure-function studies on riboswicthes, non-coding RNAs whose sensing domains bind small ligands and whose adjacent expression platforms contain RNA elements involved in the control of gene regulation. We now report on the ligand-bound structure of the Thermotoga petrophila fluoride riboswitch, which adopts a higher-order RNA architecture stabilized by pseudoknot and long-range reversed Watson-Crick and Hoogsteen A•U pair formation. The bound fluoride ion is encapsulated within the junctional architecture, anchored in place through direct coordination to three Mg2+ ions, which in turn are octahedrally coordinated to waters and five inwardly-pointing backbone phosphates. Our structure of the fluoride riboswitch in the bound state defines how RNA can form a binding pocket selective for fluoride, while discriminating against larger halide ions. The T. petrophila fluoride riboswitch most likely functions in gene regulation through a transcription termination mechanism. PMID:22678284

In Vitro Study of Directly Bioprinted Perfusable Vasculature Conduits.

PubMed

Zhang, Yahui; Yu, Yin; Akkouch, Adil; Dababneh, Amer; Dolati, Farzaneh; Ozbolat, Ibrahim T

2015-01-01

The ability to create three dimensional (3D) thick tissues is still a major tissue engineering challenge. It requires the development of a suitable vascular supply for an efficient media exchange. An integrated vasculature network is particularly needed when building thick functional tissues and/or organs with high metabolic activities, such as the heart, liver and pancreas. In this work, human umbilical vein smooth muscle cells (HUVSMCs) were encapsulated in sodium alginate and printed in the form of vasculature conduits using a coaxial deposition system. Detailed investigations were performed to understand the dehydration, swelling and degradation characteristics of printed conduits. In addition, because perfusional, permeable and mechanical properties are unique characteristics of natural blood vessels, for printed conduits these properties were also explored in this work. The results show that cells encapsulated in conduits had good proliferation activities and that their viability increased during prolonged in vitro culture. Deposition of smooth muscle matrix and collagen was observed around the peripheral and luminal surface in long-term cultured cellular vascular conduit through histology studies.

Simulating an underwater vehicle self-correcting guidance system with Simulink

NASA Astrophysics Data System (ADS)

Fan, Hui; Zhang, Yu-Wen; Li, Wen-Zhe

2008-09-01

Underwater vehicles have already adopted self-correcting directional guidance algorithms based on multi-beam self-guidance systems, not waiting for research to determine the most effective algorithms. The main challenges facing research on these guidance systems have been effective modeling of the guidance algorithm and a means to analyze the simulation results. A simulation structure based on Simulink that dealt with both issues was proposed. Initially, a mathematical model of relative motion between the vehicle and the target was developed, which was then encapsulated as a subsystem. Next, steps for constructing a model of the self-correcting guidance algorithm based on the Stateflow module were examined in detail. Finally, a 3-D model of the vehicle and target was created in VRML, and by processing mathematical results, the model was shown moving in a visual environment. This process gives more intuitive results for analyzing the simulation. The results showed that the simulation structure performs well. The simulation program heavily used modularization and encapsulation, so has broad applicability to simulations of other dynamic systems.

Tuning the conductance of H2O@C60 by position of the encapsulated H2O

PubMed Central

Zhu, Chengbo; Wang, Xiaolin

2015-01-01

The change of conductance of single-molecule junction in response to various external stimuli is the fundamental mechanism for the single-molecule electronic devices with multiple functionalities. We propose the concept that the conductance of molecular systems can be tuned from inside. The conductance is varied in C60 with encapsulated H2O, H2O@C60. The transport properties of the H2O@C60-based nanostructure sandwiched between electrodes are studied using first-principles calculations combined with the non-equilibrium Green’s function formalism. Our results show that the conductance of the H2O@C60 is sensitive to the position of the H2O and its dipole direction inside the cage with changes in conductance up to 20%. Our study paves a way for the H2O@C60 molecule to be a new platform for novel molecule-based electronics and sensors. PMID:26643873

On the mechanism of action of gated molecular baskets: The synchronicity of the revolving motion of gates and in/out trafficking of guests

PubMed Central

Hermann, Keith; Rieth, Stephen; Taha, Hashem A; Wang, Bao-Yu; Hadad, Christopher M

2012-01-01

Summary We used dynamic 1H NMR spectroscopic methods to examine the kinetics and thermodynamics of CH3CCl3 (2) entering and leaving the gated molecular basket 1. We found that the encapsulation is first-order in basket 1 and guest 2, while the decomplexation is zeroth-order in the guest. Importantly, the interchange mechanism in which a molecule of CH3CCl3 directly displaces the entrapped CH3CCl3 was not observed. Furthermore, the examination of the additivity of free energies characterizing the encapsulation process led to us to deduce that the revolving motion of the gates and in/out trafficking of guests is synchronized, yet still a function of the affinity of the guest for occupying the basket: Specifically, the greater the affinity of the guest for occupying the basket, the less effective the gates are in “sweeping” the guest as the gates undergo their revolving motion. PMID:22423275

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform

PubMed Central

Abalde-Cela, Sara; Gould, Anna; Liu, Xin; Kazamia, Elena; Smith, Alison G.; Abell, Chris

2015-01-01

Ethanol production by microorganisms is an important renewable energy source. Most processes involve fermentation of sugars from plant feedstock, but there is increasing interest in direct ethanol production by photosynthetic organisms. To facilitate this, a high-throughput screening technique for the detection of ethanol is required. Here, a method for the quantitative detection of ethanol in a microdroplet-based platform is described that can be used for screening cyanobacterial strains to identify those with the highest ethanol productivity levels. The detection of ethanol by enzymatic assay was optimized both in bulk and in microdroplets. In parallel, the encapsulation of engineered ethanol-producing cyanobacteria in microdroplets and their growth dynamics in microdroplet reservoirs were demonstrated. The combination of modular microdroplet operations including droplet generation for cyanobacteria encapsulation, droplet re-injection and pico-injection, and laser-induced fluorescence, were used to create this new platform to screen genetically engineered strains of cyanobacteria with different levels of ethanol production. PMID:25878135

Literature Review: Weldability of Iridium DOP-26 Alloy for General Purpose Heat Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgardt, Paul; Pierce, Stanley W.

The basic purpose of this paper is to provide a literature review relative to fabrication of the General Purpose Heat Source (GPHS) that is used to provide electrical power for deep space missions of NASA. The particular fabrication operation to be addressed here is arc welding of the GPHS encapsulation. A considerable effort was made to optimize the fabrication of the fuel pellets and of other elements of the encapsulation; that work will not be directly addressed in this paper. This report consists of three basic sections: 1) a brief description of the GPHS will be provided as background informationmore » for the reader; 2) mechanical properties and the optimization thereof as relevant to welding will be discussed; 3) a review of the arc welding process development and optimization will be presented. Since the welding equipment must be upgraded for future production, some discussion of the historical establishment of relevant welding variables and possible changes thereto will also be discussed.« less

Extrapolating Accelerated UV Weathering Data: Perspective From PVQAT Task Group 5 (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, D.; Annigoni, E.; Ballion, A.

2015-02-01

Taskgroup 5 (TG5) is concerned with a accelerated aging standard incorporating factors including ultraviolet radiation, temperature, and moisture. Separate experiments are being conducted in support of a test standard via the regional sub-groups in Asia, Europe, and the United States. The authors will describe the objectives and timeline for the TG5 interlaboratory study being directed out of the USA. Qualitative preliminary data from the experiment is presented. To date, the encapsulation transmittance experiment has: replicated behaviors of fielded materials (including specimen location- and formulation additive-specific discoloration); demonstrated coupling between UV aging and temperature; demonstrated that degradation in EVA results frommore » UV- aging; and obtained good qualitative comparison between Xe and UVA-340 sources for EVA. To date, the encapsulation adhesion experiment (using the compressive shear test to quantify strength of attachment) has demonstrated that attachment strength can decrease drastically (>50%) with age; however, early results suggest significant factor (UV, T, RH) dependence. Much remains to be learned about adhesion.« less

Human beta-cell precursors mature into functional insulin-producing cells in an immunoisolation device: implications for diabetes cell therapies.

PubMed

Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y; Geron, Ifat; Strongin, Alex Y; Itkin-Ansari, Pamela

2009-04-15

Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human beta-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human beta-cells and their progenitors and (2) the engraftment of encapsulated murine beta-cells in allo- and autoimmune settings. Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells ameliorated diabetes without stimulating a detectable T-cell response. We demonstrate for the first time that human beta-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of beta-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells.

Crystal structures and magnetic properties of polyethylene glycol (PEG-4000) and silica-encapsulated nickel ferrite (NiFe2O4) nanoparticles

NASA Astrophysics Data System (ADS)

Shofiah, Siti; Muflihatun, Suharyadi, Edi

2016-04-01

Crystal structures and magnetic properties of polyethylene glycol (PEG-4000) and silica encapsulated nickel ferrite (NiFe2O4) nanoparticles comparable sizes have been studied in detail. NiFe2O4 were prepared by co-precipitation methods. Crystalline size is 4.8 ± 0.2 nm became 1.6 ± 0.1 nm and 10.6 ± 0.3 nm after encapsulated PEG-4000 and silica, respectively. Transmission electron microscopy (TEM) showed that encapsulated PEG-4000 and silica decreased agglomeration, controlled shape of nanoparticles more spherical and dispersed. Coercivity of NiFe2O4 was 46.2 Oe and then increased after encapsulated PEG-4000 to 47.8 Oe can be related to the multi-domains of NiFe2O4 as influence the crystalline size was decreased. Meanwhile, after encapsulated silica, coercivity of NiFe2O4 became 93 Oe as influence the crystalline size was increased at single-domains due to its strong shape anisotropy. Magnetization value decreased from 5.7 emu/g to 5.3 emu/g and 3.6 emu/g after encapsulated PEG-4000 and silica, respectively. The remanent magnetization showed decreasing when saturation magnetization decreased, and conversely. However, it also depends on presence of α-Fe2O3 phases and their material non magnetic of encapsulating. Based on the result, The magnetic properties exhibit a strong dependence on the crystalline size as influence PEG-4000 and silica encapsulated NiFe2O4 nanoparticles.

Simplified procedure for encapsulating cytochrome c in silica aerogel nanoarchitectures while retaining gas-phase bioactivity.

PubMed

Harper-Leatherman, Amanda S; Iftikhar, Mariam; Ndoi, Adela; Scappaticci, Steven J; Lisi, George P; Buzard, Kaitlyn L; Garvey, Elizabeth M

2012-10-16

Cytochrome c (cyt. c) has been encapsulated in silica sol-gels and processed to form bioaerogels with gas-phase activity for nitric oxide through a simplified synthetic procedure. Previous reports demonstrated a need to adsorb cyt. c to metal nanoparticles prior to silica sol-gel encapsulation and processing to form aerogels. We report that cyt. c can be encapsulated in aerogels without added nanoparticles and retain structural stability and gas-phase activity for nitric oxide. While the UV-visible Soret absorbance and nitric oxide response indicate that cyt. c encapsulated with nanoparticles in aerogels remains slightly more stable and functional than cyt. c encapsulated alone, these properties are not very different in the two types of aerogels. From UV-visible and Soret circular dichroism results, we infer that cyt. c encapsulated alone self-organizes to reduce contact with the silica gel in a way that may bear at least some resemblance to the way cyt. c self-organizes into superstructures of protein within aerogels when nanoparticles are present. Both the buffer concentration and the cyt. c concentration of solutions used to synthesize the bioaerogels affect the structural integrity of the protein encapsulated alone within the dried aerogels. Optimized bioaerogels are formed when cyt. c is encapsulated from 40 mM phosphate buffered solutions, and when the loaded cyt. c concentration in the aerogel is in the range of 5 to 15 μM. Increased viability of cyt. c in aerogels is also observed when supercritical fluid used to produce aerogels is vented over relatively long times.

An accelerated stress testing program for determining the reliability sensitivity of silicon solar cells to encapsulation and metallization systems

NASA Technical Reports Server (NTRS)

Lathrop, J. W.; Davis, C. W.; Royal, E.

1982-01-01

The use of accelerated testing methods in a program to determine the reliability attributes of terrestrial silicon solar cells is discussed. Different failure modes are to be expected when cells with and without encapsulation are subjected to accelerated testing and separate test schedules for each are described. Unencapsulated test cells having slight variations in metallization are used to illustrate how accelerated testing can highlight different diffusion related failure mechanisms. The usefulness of accelerated testing when applied to encapsulated cells is illustrated by results showing that moisture related degradation may be many times worse with some forms of encapsulation than with no encapsulation at all.

Long-lifetime thin-film encapsulated organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Wong, F. L.; Fung, M. K.; Tao, S. L.; Lai, S. L.; Tsang, W. M.; Kong, K. H.; Choy, W. M.; Lee, C. S.; Lee, S. T.

2008-07-01

Multiple fluorocarbon (CFx) and silicon nitride (Si3N4) bilayers were applied as encapsulation cap on glass-based organic light-emitting diodes (OLEDs). When CFx/Si3N4 bilayers were deposited onto the OLED structure, the devices showed performance worse than one without any encapsulation. The adverse effects were attributed to the damage caused by reaction species during the thin-film deposition processes. To solve this problem, a CuPc interlayer was found to provide effective protection to the OLED structure. With a structure of CuPc/(CFx/Si3N4)×5, the encapsulated device showed an operation lifetime over 8000 h (higher than 80% of that achieved with a conventional metal encapsulation).

Functional assessment of encapsulated citral for controlling necrotic enteritis in broiler chickens.

PubMed

Yang, Yuexi; Wang, Qi; Diarra, Moussa S; Yu, Hai; Hua, Yufei; Gong, Joshua

2016-04-01

Development of viable alternatives to antibiotics to control necrotic enteritis (NE) caused by Clostridium perfringensis becoming urgent for chicken production due to pessures on poultry producers to limit or stop the use of antibiotics in feed. We have previously identified citral as a potential alternative to antibiotics. Citral has strong antimicrobial activity and can be encasupsulated in a powder form for protection from loss during feed processing, storage, and intestinal delivery. In the present study, encapsulated citral was evaluated both in vitro and in vivo for its antimicrobial activity against C. perfringens Encapsulation did not adversely affect the antimicrobial activity of citral. In addition, encapsulated citral was superior to the unencapsulated form in retaining its antimicrobial activity after treatment with simulated gastrointestinal fluids and in the presence of chicken intestinal digesta. In addition, the higher antimicrobial activity of encapsulated citral was confirmed in digesta samples from broilers that had been gavaged with encapsulated or unencapsulated citral. In broilers infected with C. perfringens, the diets supplemented with encapsualted citral at both 250 and 650 μg/g significantly reduced intestinal NE lesions, which was comparable to the effect of bacitracin- and salinomycin-containing diets. However, supplementation with the encapsulated citral appeared to have no significant impact on the intestinal burden of Lactobacillus These data indicate that citral can be used to control NE in chickens after proper protection by encapsulation. © Crown copyright 2016.

UV-screening chitosan nanocontainers: increasing the photostability of encapsulated materials and controlled release

NASA Astrophysics Data System (ADS)

Anumansirikul, Nattaporm; Wittayasuporn, Mayura; Klinubol, Patcharawalai; Tachaprutinun, A.; Wanichwecharungruang, Supason P.

2008-05-01

Methyl ether terminated poly(ethylene glycol)-4-methoxycinnamoylphthaloylchitosan (PCPLC), a UV absorptive polymer, and methyl ether terminated poly(ethylene glycol)-phthaloylchitosan (PPLC) were synthesized, characterized and self-assembled into stable water-dispersible spherical nanoparticles. The encapsulation of a model compound, 2-ethylhexyl-4-methoxycinnamate (EHMC), was carried out to give particles with 67% (w/w) EHMC loading. The E to Z photoisomerization of EHMC encapsulated inside both particles was monitored and compared to non-encapsulated EHMC. Minimal E to Z photoisomerization was observed when EHMC was encapsulated in PCPLC particles prepared from a polymer with a maximum degree of 4-methoxycinnamoyl substitution. The results indicated that the grafted UVB absorptive chromophore, 4-methoxycinnamoyl moieties, situated at the shell of PCPLC nanoparticles acted as a UV-filtering barrier, protecting the encapsulated EHMC from the UVB radiation, thus minimizing its photoisomerization. In vitro experiments revealed the pH-dependent controlled release of EHMC from PCPLC and PPLC particles. Ex vivo experiments, using a Franz diffusion cell with baby mouse skin, indicated that neither PPLC nor PCPLC particles could penetrate the skin into the receptor medium after a 24 h topical application. When applied on the baby mouse skin, both EHMC-encapsulated PPLC and EHMC-encapsulated PCPLC showed comparable controlled releases of the EHMC. The released EHMC could transdermally penetrate the baby mouse skin.

Pseudotumoral encapsulated fat necrosis with diffuse pseudomembranous degeneration.

PubMed

Felipo, F; Vaquero, M; del Agua, C

2004-09-01

An extraordinary case of encapsulated fat necrosis characterized by its large size, diffuse formation of pseudomembranes, and tendency to recur after excision is reported. A 67-year-old Caucasian woman suffering from morbid obesity was admitted for diagnosis and surgical treatment of a soft tissue mass showing a longest diameter of 14 cm and lying adjacently to the scar from previous appendicectomy. Histopathologic features were consistent with a nodular-cystic encapsulated fat necrosis with diffuse pseudomembranous transformation. Eight months after surgery, a new larger mass (longest diameter of 18 cm) sharing identical histopathologic features appeared in the same location. Encapsulated fat necrosis is a well-defined entity even though several names have been proposed for this condition, including mobile encapsulated lipoma, encapsulated necrosis, or nodular-cystic fat necrosis. Its pathogenesis seems to be related to ischemic changes secondary to previous trauma. It may occasionally show degenerative changes, including dystrophic calcifications and presence of pseudomembranes. To our knowledge, these are the first reported cases of encapsulated fat necrosis presenting as lesions of such size and showing diffuse formation of pseudomembranes; these particular features made diagnosis difficult and led to consideration of a wide range of potential diagnostic possibilities. This case expands the clinico-pathologic spectrum of membranocystic fat necrosis, including the potential ability of this subcutaneous fatty tissue abnormality to recur after surgical excision. Felipo F, Vaquero M, del Agua C. Pseudotumoral encapsulated fat necrosis with diffuse pseudomembranous degeneration.

The Advanced Glaucoma Intervention Study (AGIS): 5. Encapsulated bleb after initial trabeculectomy.

PubMed

Schwartz, A L; Van Veldhuisen, P C; Gaasterland, D E; Ederer, F; Sullivan, E K; Cyrlin, M N

1999-01-01

To compare the incidence of encapsulated bleb after trabeculectomy in eyes with and without previous argon laser trabeculoplasty and to assess other risk factors for encapsulated bleb development. After medical treatment failure, eyes enrolled in the Advanced Glaucoma Intervention Study (AGIS) were randomly assigned to sequences of interventions starting with either argon laser trabeculoplasty or trabeculectomy. In the present study we compared the clinical course for 1 year after trabeculectomy in 119 eyes with failed argon laser trabeculoplasty with that of 379 eyes without previous argon laser trabeculoplasty. Data on bleb encapsulation were collected at the time that the encapsulation was diagnosed, and 3 and 6 months later. Of multiple factors examined in the AGIS data for the risk of developing encapsulated bleb, only male gender and high school graduation without further formal education were statistically significant. Encapsulation occurred in 18.5% of eyes with previous argon laser trabeculoplasty failure and 14.5% of eyes without previous argon laser trabeculoplasty (unadjusted relative risk, 1.27; 95% confidence limits = 0.81, 2.00; P = .23). After adjusting for age, gender, educational achievement, prescribed systemic beta-blockers, diabetes, visual field score, and years since glaucoma diagnosis, this difference remains statistically not significant. Four weeks after trabeculectomy, mean intraocular pressure was 7.5 mm Hg higher in eyes with (22.5 mm Hg) than without (15.0 mm Hg) encapsulated bleb; at 1 year after trabeculectomy and the resumption of medical therapy when needed, this excess was reduced to 1.4 mm Hg. This study, as did two previous studies, found male gender to be a risk factor for bleb encapsulation. Four studies, including the present study, have reported a higher rate of encapsulation in eyes with previous argon laser trabeculoplasty; in two of the studies, one of which was the present study, the rate was not statistically significantly higher; in the other two studies the rate was significantly higher. The 4-week postoperative mean intraocular pressure was higher in eyes with than without encapsulated bleb; with the resumption of medical treatment the two means converged after 1 year.

Antinociception and side effects of L- and D-dipalmitoylphosphatidyl choline liposome-encapsulated alfentanil after spinal delivery in rats.

PubMed

Isackson, J; Wallace, M S; Ho, R J; Shen, D D; Yaksh, T L

1995-11-01

We have observed that spinal liposome administration in the rat resulted in in an allodynia evoked by light touch. We later determined that liposomes composed of D-isomer phospholipids were essentially non-toxic. This study examines the effects of alfentanil encapsulated in liposomes made from the natural L-isomer and synthetic D-isomer of dipalmitoyl phosphatidyl choline on antinoceiception, side effects, and algogenic behaviour. Both unilamellar and multilamellar liposomes were studied. Rats prepared with chronic intrathecal catheters received intrathecal injections of alfentanil (5 or 50 micrograms) in saline or encapsulated in liposomes composed of either L- or D-isomers of dipalmitoyl phosphatidyl choline (DPPC) in unilamellar or multilamellar liposome formulations. Antinociception was measured using the hot plate test (52.5 degrees). Side effects were measured by catalepsy, corneal responses, pinna response, righting reflex, and paw step. Allodynia was measured by lightly stroking the animal's back. Intrathecal alfentanil in saline or in the liposomes produced a dose-dependent increased latency in the hot plate response. Encapsulation of alfentanil in the liposomes produced a significant decrease in the loss of corneal, paw step and righting reflex and a slight decrease in catalepsy and loss of the pinna response. There was no significant difference between liposome preparations in preventing side effects. L-multilamellar-DPPC produced allodynia in 100% of the animals whereas significantly less allodynia was observed with the other preparations. This study indicates that liposomal preparations can significantly enhance the therapeutic ratio of a lipid soluble opioid after spinal delivery. However, the choice of lipids for the formulation of liposomes intended for spinal drug delivery must be considered since the L-isomer and larger lipid load of multilamellar liposomes have a direct spinal effect leading to alledynia. Previous studies have in fact shown that spinal lysolecithin can yield focal demyelination.

Does encapsulation protect embryos from the effects of ocean acidification? The example of Crepidula fornicata.

PubMed

Noisette, Fanny; Comtet, Thierry; Legrand, Erwann; Bordeyne, François; Davoult, Dominique; Martin, Sophie

2014-01-01

Early life history stages of marine organisms are generally thought to be more sensitive to environmental stress than adults. Although most marine invertebrates are broadcast spawners, some species are brooders and/or protect their embryos in egg or capsules. Brooding and encapsulation strategies are typically assumed to confer greater safety and protection to embryos, although little is known about the physico-chemical conditions within egg capsules. In the context of ocean acidification, the protective role of encapsulation remains to be investigated. To address this issue, we conducted experiments on the gastropod Crepidula fornicata. This species broods its embryos within capsules located under the female and veliger larvae are released directly into the water column. C. fornicata adults were reared at the current level of CO2 partial pressure (pCO2) (390 μatm) and at elevated levels (750 and 1400 μatm) before and after fertilization and until larval release, such that larval development occurred entirely at a given pCO2. The pCO2 effects on shell morphology, the frequency of abnormalities and mineralization level were investigated on released larvae. Shell length decreased by 6% and shell surface area by 11% at elevated pCO2 (1400 μatm). The percentage of abnormalities was 1.5- to 4-fold higher at 750 μatm and 1400 μatm pCO2, respectively, than at 390 μatm. The intensity of birefringence, used as a proxy for the mineralization level of the larval shell, also decreased with increasing pCO2. These negative results are likely explained by increased intracapsular acidosis due to elevated pCO2 in extracapsular seawater. The encapsulation of C. fornicata embryos did not protect them against the deleterious effects of a predicted pCO2 increase. Nevertheless, C. fornicata larvae seemed less affected than other mollusk species. Further studies are needed to identify the critical points of the life cycle in this species in light of future ocean acidification.

Anti-tumor therapy with macroencapsulated endostatin producer cells

PubMed Central

2010-01-01

Background Theracyte is a polytetrafluoroethylene membrane macroencapsulation system designed to induce neovascularization at the tissue interface, protecting the cells from host's immune rejection, thereby circumventing the problem of limited half-life and variation in circulating levels. Endostatin is a potent inhibitor of angiogenesis and tumor growth. Continuous delivery of endostatin improves the efficacy and potency of the antitumoral therapy. The purpose of this study was to determine whether recombinant fibroblasts expressing endostatin encapsulated in Theracyte immunoisolation devices can be used for delivery of this therapeutic protein for treatment of mice bearing B16F10 melanoma and Ehrlich tumors. Results Mice were inoculated subcutaneously with melanoma (B16F10 cells) or Ehrlich tumor cells at the foot pads. Treatment began when tumor thickness had reached 0.5 mm, by subcutaneous implantation of 107 recombinant encapsulated or non-encapsulated endostatin producer cells. Similar melanoma growth inhibition was obtained for mice treated with encapsulated or non-encapsulated endostatin-expressing cells. The treatment of mice bearing melanoma tumor with encapsulated endostatin-expressing cells was decreased by 50.0%, whereas a decrease of 56.7% in tumor thickness was obtained for mice treated with non-encapsulated cells. Treatment of Ehrlich tumor-bearing mice with non-encapsulated endostatin-expressing cells reduced tumor thickness by 52.4%, whereas lower tumor growth inhibition was obtained for mice treated with encapsulated endostatin-expressing cells: 24.2%. Encapsulated endostatin-secreting fibroblasts failed to survive until the end of the treatment. However, endostatin release from the devices to the surrounding tissues was confirmed by immunostaining. Decrease in vascular structures, functional vessels and extension of the vascular area were observed in melanoma microenvironments. Conclusions This study indicates that immunoisolation devices containing endostatin-expressing cells are effective for the inhibition of the growth of melanoma and Ehrlich tumors. Macroencapsulation of engineered cells is therefore a reliable platform for the refinement of innovative therapeutic strategies against tumors. PMID:20196841

Anti-tumor therapy with macroencapsulated endostatin producer cells.

PubMed

Rodrigues, Danielle B; Chammas, Roger; Malavasi, Natália V; da Costa, Patrícia L N; Chura-Chambi, Rosa M; Balduino, Keli N; Morganti, Ligia

2010-03-02

Theracyte is a polytetrafluoroethylene membrane macroencapsulation system designed to induce neovascularization at the tissue interface, protecting the cells from host's immune rejection, thereby circumventing the problem of limited half-life and variation in circulating levels. Endostatin is a potent inhibitor of angiogenesis and tumor growth. Continuous delivery of endostatin improves the efficacy and potency of the antitumoral therapy. The purpose of this study was to determine whether recombinant fibroblasts expressing endostatin encapsulated in Theracyte immunoisolation devices can be used for delivery of this therapeutic protein for treatment of mice bearing B16F10 melanoma and Ehrlich tumors. Mice were inoculated subcutaneously with melanoma (B16F10 cells) or Ehrlich tumor cells at the foot pads. Treatment began when tumor thickness had reached 0.5 mm, by subcutaneous implantation of 107 recombinant encapsulated or non-encapsulated endostatin producer cells. Similar melanoma growth inhibition was obtained for mice treated with encapsulated or non-encapsulated endostatin-expressing cells. The treatment of mice bearing melanoma tumor with encapsulated endostatin-expressing cells was decreased by 50.0%, whereas a decrease of 56.7% in tumor thickness was obtained for mice treated with non-encapsulated cells. Treatment of Ehrlich tumor-bearing mice with non-encapsulated endostatin-expressing cells reduced tumor thickness by 52.4%, whereas lower tumor growth inhibition was obtained for mice treated with encapsulated endostatin-expressing cells: 24.2%. Encapsulated endostatin-secreting fibroblasts failed to survive until the end of the treatment. However, endostatin release from the devices to the surrounding tissues was confirmed by immunostaining. Decrease in vascular structures, functional vessels and extension of the vascular area were observed in melanoma microenvironments. This study indicates that immunoisolation devices containing endostatin-expressing cells are effective for the inhibition of the growth of melanoma and Ehrlich tumors.Macroencapsulation of engineered cells is therefore a reliable platform for the refinement of innovative therapeutic strategies against tumors.

Stability of free and encapsulated Lactobacillus acidophilus ATCC 4356 in yogurt and in an artificial human gastric digestion system.

PubMed

Ortakci, F; Sert, S

2012-12-01

The objective of this study was to determine the effect of encapsulation on survival of probiotic Lactobacillus acidophilus ATCC 4356 (ATCC 4356) in yogurt and during artificial gastric digestion. Strain ATCC 4356 was added to yogurt either encapsulated in calcium alginate or in free form (unencapsulated) at levels of 8.26 and 9.47 log cfu/g, respectively, and the influence of alginate capsules (1.5 to 2.5mm) on the sensorial characteristics of yogurts was investigated. The ATCC 4356 strain was introduced into an artificial gastric solution consisting of 0.08 N HCl (pH 1.5) containing 0.2% NaCl or into artificial bile juice consisting of 1.2% bile salts in de Man, Rogosa, and Sharpe broth to determine the stability of the probiotic bacteria. When incubated for 2h in artificial gastric juice, the free ATCC 4356 did not survive (reduction of >7 log cfu/g). We observed, however, greater survival of encapsulated ATCC 4356, with a reduction of only 3 log cfu/g. Incubation in artificial bile juice (6 h) did not significantly affect the viability of free or encapsulated ATCC 4356. Moreover, statistically significant reductions (~1 log cfu/g) of both free and encapsulated ATCC 4356 were observed during 4-wk refrigerated storage of yogurts. The addition of probiotic cultures in free or alginate-encapsulated form did not significantly affect appearance/color or flavor/odor of the yogurts. However, significant deficiencies were found in body/texture of yogurts containing encapsulated ATCC 4356. We concluded that incorporation of free and encapsulated probiotic bacteria did not substantially change the overall sensory properties of yogurts, and encapsulation in alginate using the extrusion method greatly enhanced the survival of probiotic bacteria against an artificial human gastric digestive system. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Properties of Lactobacillus reuteri chitosan-calcium-alginate encapsulation under simulated gastrointestinal conditions.

PubMed

Huang, Hui-Ying; Tang, Yi-Ju; King, V An-Erl; Chou, Jen-Wei; Tsen, Jen-Horng

2015-03-01

The protective effects of encapsulation on the survival of Lactobacillus reuteri and the retention of the bacterium's probiotic properties under simulated gastrointestinal conditions were investigated. Viable counts and the remaining probiotic properties of calcium (Ca)-alginate encapsulated (A group), chitosan-Ca-alginate encapsulated (CA group), and unencapsulated, free L. reuteri (F group) were determined. Encapsulation improved the survival of L. reuteri subjected to simulated gastrointestinal conditions, with the greatest protective effect achieved in the CA group. The degree of cell membrane injury increased with increasing bile salt concentrations at constant pH, but the extent of injury was less in the encapsulated than in the free cells. Adherence rates were, in descending order: CA (0.524%)>A (0.360%)>F (0.275%). Lactobacillus reuteri cells retained their antagonistic activity toward Listeria monocytogenes even after incubation of the lactobacilli under simulated gastrointestinal conditions. Displacement of the pathogen by cells released from either of the encapsulation matrices was higher than that by free cells. The safety of L. reuteri was demonstrated in an in vitro invasion assay. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Encapsulating Non-Human Primate Multipotent Stromal Cells in Alginate via High Voltage for Cell-Based Therapies and Cryopreservation

PubMed Central

Gryshkov, Oleksandr; Pogozhykh, Denys; Hofmann, Nicola; Pogozhykh, Olena; Mueller, Thomas; Glasmacher, Birgit

2014-01-01

Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedure and cell concentration do not affect the diameter of alginate beads, ii) encapsulation of high cell numbers (up to 10×106 cells/ml) can be performed in alginate beads utilizing high voltage and iii) high voltage (15–30 kV) does not alter the viability, proliferation and differentiation capacity of MSCs post-encapsulation compared with alginate encapsulated cells produced by the traditional air-flow method. The consistent results were obtained over the period of 7 days of encapsulated MSCs culture and after cryopreservation utilizing a slow cooling procedure (1 K/min). The results of this work show that high voltage encapsulation can further be maximized to develop cell-based therapies with alginate beads in a non-human primate model towards human application. PMID:25259731

Polyamide nanocapsules and nano-emulsions containing Parsol® MCX and Parsol® 1789: in vitro release, ex vivo skin penetration and photo-stability studies.

PubMed

Hanno, Ibrahim; Anselmi, Cecilia; Bouchemal, Kawthar

2012-02-01

To prepare polyamide nanocapsules for skin photo-protection, encapsulating α-tocopherol, Parsol®MCX (ethylhexyl methoxycinnamate) and/or Parsol®1789 (butyl methoxydibenzoylmethane). Nanocapsules were obtained by combining spontaneous emulsification and interfacial polycondensation reaction between sebacoyl chloride and diethylenetriamine. Nano-emulsions used as control were obtained by the same process without monomers. The influence of carrier on release rate was studied in vitro with a membrane-free model. Epidermal penetration of encapsulated sunscreens was ex vivo evaluated using Franz diffusion cells. Ability of encapsulated sunscreens to improve photo-stability was verified by comparing percentage of degradation after UV radiation exposure. Sunscreen-containing nanocapsules (260-400 nm) were successfully prepared; yield of encapsulation was >98%. Parsol®MCX and Parsol®1789 encapsulation led to decreased release rate by up to 60% in comparison with nano-emulsion and allowed minimum penetration through pig ear epidermis. Presence of polyamide shell protected encapsulated sunscreen filters from photo-degradation without affecting their activity. Encapsulation of Parsol®MCX and Parsol®1789 into oil-core of polyamide nanocapsules allowed protection from photo-degradation, controlled release from nanocapsules, and limited penetration through pig ear epidermis.

Color, bioactive compounds and morphological characteristics of encapsulated Asian pear juice powder during spray drying.

PubMed

Lee, Chang-Gon; Ahmed, Maruf; Jiang, Gui-Hun; Eun, Jong-Bang

2017-08-01

Encapsulated Asian pear juice powder was produced through spray drying using three maltodextrin levels (15, 20, and 25% w/v) and three inlet air temperatures (130, 150, and 170 °C). The impact of maltodextrin concentrations and inlet air temperatures on color, bioactive compounds, and morphological characteristics of encapsulated Asian pear juice powder were investigated. Maltodextrin concentrations and inlet air temperatures significantly influenced L * and b * values of encapsulated Asian pear juice powder. Increasing inlet air temperatures increased total phenolic content, whereas the vitamin C content decreased. Vitamin C content was strongly correlated with particle size, inlet air temperature, and maltodextrin concentration. ABTS + radical-scavenging activity was highly correlated with total phenol content while DPPH radical-scavenging activity was highly correlated with vitamin C content. Encapsulated powders made with higher inlet air temperature and higher maltodextrin concentration had lowest median particle diameter with a smoother, more regular and rounded outer surface than those of encapsulated powders produced with lower inlet air temperature and lower maltodextrin concentration. Therefore, the results demonstrate that high-quality encapsulated Asian pear juice powder could be manufactured by adding 15% (w/v) maltodextrin and spray-drying at 170 °C.

Direct quantitative comparison of molecular responses in photodamaged human skin to fractionated and fully ablative carbon dioxide laser resurfacing.

PubMed

Orringer, Jeffrey S; Sachs, Dana L; Shao, Yuan; Hammerberg, Craig; Cui, Yilei; Voorhees, John J; Fisher, Gary J

2012-10-01

Fractionated ablative laser resurfacing has become a widely used treatment modality. Its clinical results are often found to approach those of traditional fully ablative laser resurfacing. To directly compare the molecular changes that result from fractionated and fully ablative carbon dioxide (CO(2)) laser resurfacing in photodamaged human skin. Photodamaged skin of 34 adult volunteers was focally treated at distinct sites with a fully ablative CO(2) laser and a fractionated CO(2) laser. Serial skin samples were obtained at baseline and several time points after treatment. Real-time reverse transcriptase polymerase chain reaction technology and immunohistochemistry were used to quantify molecular responses to each type of laser treatment. Fully ablative and fractionated CO(2) laser resurfacing induced significant dermal remodeling and collagen induction. After a single treatment, fractionated ablative laser resurfacing resulted in collagen induction that was approximately 40% to 50% as pronounced as that induced by fully ablative laser resurfacing. The fundamental cutaneous responses that result from fully ablative and fractionated carbon dioxide laser resurfacing are similar but differ in magnitude and duration, with the fully ablative procedure inducing relatively greater changes including more pronounced collagen induction. However, the molecular data reported here provide substantial support for fractionated ablative resurfacing as an effective treatment modality for improving skin texture. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

POLYETHYLENE ENCAPSULATES FOR HAZARDOUS WASTE DRUMS

EPA Science Inventory

This capsule report summarizes studies of the use of polyethylene (P.E.) for encapsulating drums of hazardous wastes. Flat PE sheet is welded to roto moded PE containers which forms the encapsulates. Plastic pipe welding art was used, but the prototype welding apparatus required ...

Liquid encapsulated crystal growth

NASA Technical Reports Server (NTRS)

Morrison, Andrew D. (Inventor)

1989-01-01

Low-defect crystals are grown in a closed ampoule under a layer of encapsulant. After crystal growth, the crystal is separated from the melt and moved into the layer of encapsulant and cooled to a first temperature at which crystal growth stops. The crystal is then moved into the inert gas ambient in the ampoule and further cooled. The crystal can be separated from the melt by decanting the melt into an adjacent reservoir or by rotating the ampoule to rotate the crystal into the encapsulant layer.

Liquid encapsulated crystal growth

NASA Technical Reports Server (NTRS)

Morrison, Andrew D. (Inventor)

1987-01-01

Low-defect crystals are grown in a closed ampoule under a layer of encapsulant. After crystal growth, the crystal is separated from the melt and moved into the layer of encapsulant and cooled to a first temperature at which crystal growth stops. The crystal is then moved into the inert gas ambient in the ampoule and further cooled. The crystal can be separated from the melt by decanting the melt into and adjacent reservoir or by rotating the ampoule to rotate the crystal into the encapsulant layer.

Human β-cell Precursors Mature Into Functional Insulin-producing Cells in an Immunoisolation Device: Implications for Diabetes Cell Therapies

PubMed Central

Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y.; Geron, Ifat; Strongin, Alex Y.; Itkin-Ansari, Pamela

2009-01-01

Background Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human β-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human β-cells and their progenitors and (2) the engraftment of encapsulated murine β-cells in allo- and autoimmune settings. Methods Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Results Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary β-cells ameliorated diabetes without stimulating a detectable T-cell response. Conclusions We demonstrate for the first time that human β-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of β-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells. PMID:19352116

Crystal structures and magnetic properties of polyethylene glycol (PEG-4000) and silica-encapsulated nickel ferrite (NiFe{sub 2}O{sub 4}) nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shofiah, Siti, E-mail: esuharyadi@ugm.ac.id; Muflihatun,; Suharyadi, Edi

2016-04-19

Crystal structures and magnetic properties of polyethylene glycol (PEG-4000) and silica encapsulated nickel ferrite (NiFe{sub 2}O{sub 4}) nanoparticles comparable sizes have been studied in detail. NiFe{sub 2}O{sub 4} were prepared by co-precipitation methods. Crystalline size is 4.8 ± 0.2 nm became 1.6 ± 0.1 nm and 10.6 ± 0.3 nm after encapsulated PEG-4000 and silica, respectively. Transmission electron microscopy (TEM) showed that encapsulated PEG-4000 and silica decreased agglomeration, controlled shape of nanoparticles more spherical and dispersed. Coercivity of NiFe{sub 2}O{sub 4} was 46.2 Oe and then increased after encapsulated PEG-4000 to 47.8 Oe can be related to the multi-domains of NiFe{sub 2}O{sub 4}more » as influence the crystalline size was decreased. Meanwhile, after encapsulated silica, coercivity of NiFe{sub 2}O{sub 4} became 93 Oe as influence the crystalline size was increased at single-domains due to its strong shape anisotropy. Magnetization value decreased from 5.7 emu/g to 5.3 emu/g and 3.6 emu/g after encapsulated PEG-4000 and silica, respectively. The remanent magnetization showed decreasing when saturation magnetization decreased, and conversely. However, it also depends on presence of α-Fe{sub 2}O{sub 3} phases and their material non magnetic of encapsulating. Based on the result, The magnetic properties exhibit a strong dependence on the crystalline size as influence PEG-4000 and silica encapsulated NiFe{sub 2}O{sub 4} nanoparticles.« less

Encapsulated Pseudomonas putida for phenol biodegradation: Use of a structural membrane for construction of a well-organized confined particle.

PubMed

Kurzbaum, Eyal; Raizner, Yasmin; Cohen, Oded; Suckeveriene, Ran Y; Kulikov, Anatoly; Hakimi, Ben; Iasur Kruh, Lilach; Armon, Robert; Farber, Yair; Menashe, Ofir

2017-09-15

Phenols are toxic byproducts from a wide range of industry sectors. If not treated, they form effluents that are very hazardous to the environment. This study presents the use of a Pseudomonas putida F1 culture encapsulated within a confined environment particle as an efficient technique for phenol biodegradation. The innovative encapsulation technique method, named the "Small Bioreactor Platform" (SBP) technology, enables the use of a microfiltration membrane constructed as a physical barrier for creating a confined environment for the encapsulated culture. The phenol biodegradation rate of the encapsulated culture was compared to its suspended state in order to evaluate the effectiveness of the encapsulation technique for phenol biodegradation. A maximal phenol biodegradation rate (q) of 2.12/d was exhibited by encapsulated P. putida at an initial phenol concentration of 100 mg/L. The biodegradation rate decreased significantly at lower and higher initial phenol concentrations of 50 and up to 3000 mg/L, reaching a rate of 0.1018/d. The results also indicate similar and up to double the degradation rate between the two bacterial states (encapsulated vs. suspended). High resolution scanning electron microscopy images of the SBP capsule's membrane morphology demonstrated a highly porous microfiltration membrane. These results, together with the long-term activity of the SBP capsules and verification that the culture remains pure after 60 days using 16S rRNA gene phylogenetic affiliation tests, provide evidence for a successful application of this new encapsulation technique for bioaugmentation of selected microbial cultures in water treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

PubMed

Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar; Maspoch, Daniel; Llagostera, Montserrat

2015-07-01

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

PubMed Central

Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar

2015-01-01

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. PMID:25956778

Exploring encapsulation mechanism of DNA and mononucleotides in sol-gel derived silica.

PubMed

Kapusuz, Derya; Durucan, Caner

2017-07-01

The encapsulation mechanism of DNA in sol-gel derived silica has been explored in order to elucidate the effect of DNA conformation on encapsulation and to identify the nature of chemical/physical interaction of DNA with silica during and after sol-gel transition. In this respect, double stranded DNA and dAMP (2'-deoxyadenosine 5'-monophosphate) were encapsulated in silica using an alkoxide-based sol-gel route. Biomolecule-encapsulating gels have been characterized using UV-Vis, 29 Si NMR, FTIR spectroscopy and gas adsorption (BET) to investigate chemical interactions of biomolecules with the porous silica network and to examine the extent of sol-gel reactions upon encapsulation. Ethidium bromide intercalation and leach out tests showed that helix conformation of DNA was preserved after encapsulation. For both biomolecules, high water-to-alkoxide ratio promoted water-producing condensation and prevented alcoholic denaturation. NMR and FTIR analyses confirmed high hydraulic reactivity (water adsorption) for more silanol groups-containing DNA and dAMP encapsulated gels than plain silica gel. No chemical binding/interaction occurred between biomolecules and silica network. DNA and dAMP encapsulated silica gelled faster than plain silica due to basic nature of DNA or dAMP containing buffer solutions. DNA was not released from silica gels to aqueous environment up to 9 days. The chemical association between DNA/dAMP and silica host was through phosphate groups and molecular water attached to silanols, acting as a barrier around biomolecules. The helix morphology was found not to be essential for such interaction. BET analyses showed that interconnected, inkbottle-shaped mesoporous silica network was condensed around DNA and dAMP molecules.

Fat encapsulation enhances dietary nutrients utilization and growth performance of nursery pigs.

PubMed

Yang, F; Zhang, S H; Kim, S W; Ren, C X; Tian, M; Cheng, L; Song, J J; Chen, J; Chen, F; Guan, W T

2018-05-31

Encapsulation of fat may facilitate digestion and absorption of fat in nursery pigs. Two experiments were conducted to evaluate (1) effects of encapsulation of palm oil and coconut oil on growth performance, feed intake, feed efficiency, and blood parameters, and (2) effects of encapsulation of palm oil and coconut oil on apparent total tract digestibility (ATTD) of nutrients, and the activity of digestive enzymes in nursery pigs. In Exp. 1, 540 pigs (28 d of age, 8.23 ± 0.22 kg BW) were allotted to 5 treatments based on a randomized complete block design (as-fed basis). Pigs were fed basal diets with 5 different fat sources: 6.0% soybean oil (SBO), 6.0% palm oil (PO), 6.0% palm oil from encapsulated fat (EPO), 6.0% coconut oil (CO), and 6.0% coconut oil from encapsulated fat (ECO) respectively, with 6 pens per treatment and 18 pigs per pen for a 4-wk feeding trial. Dried casein and whey powder used for encapsulation were included at identical levels in all diets. Pigs fed EPO had increased (PPPad libitum for 4 weeks to measure ATTD of diets weekly and digestive enzyme activity at wk 4. Pigs fed EPO, CO, and ECO had increased (PPPEE) compared to other treatments. Pigs fed PO had greater (PP = 0.073) pancreatic lipase activity compared to other treatments whereas dietary treatments had no effect on pancreatic amylase activity. In conclusion, this study indicates that encapsulation of palm oil improved growth performance and ATTD of diets in nursery pigs, whereas the limited effects of encapsulated coconut oil were likely due to the high digestibility of the medium chain triglycerides (MCT) abundant in coconut oil.

Microsphere-based scaffolds encapsulating chondroitin sulfate or decellularized cartilage

PubMed Central

Gupta, Vineet; Tenny, Kevin M; Barragan, Marilyn; Berkland, Cory J; Detamore, Michael S

2016-01-01

Extracellular matrix materials such as decellularized cartilage (DCC) and chondroitin sulfate (CS) may be attractive chondrogenic materials for cartilage regeneration. The goal of the current study was to investigate the effects of encapsulation of DCC and CS in homogeneous microsphere-based scaffolds, and to test the hypothesis that encapsulation of these extracellular matrix materials would induce chondrogenesis of rat bone marrow stromal cells. Four different types of homogeneous scaffolds were fabricated from microspheres of poly(D,L-lactic-co-glycolic acid): Blank (poly(D,L-lactic-co-glycolic acid) only; negative control), transforming growth factor-β3 encapsulated (positive control), DCC encapsulated, and CS encapsulated. These scaffolds were then seeded with rat bone marrow stromal cells and cultured for 6 weeks. The DCC and CS encapsulation altered the morphological features of the microspheres, resulting in higher porosities in these groups. Moreover, the mechanical properties of the scaffolds were impacted due to differences in the degree of sintering, with the CS group exhibiting the highest compressive modulus. Biochemical evidence suggested a mitogenic effect of DCC and CS encapsulation on rat bone marrow stromal cells with the matrix synthesis boosted primarily by the inherently present extracellular matrix components. An important finding was that the cell seeded CS and DCC groups at week 6 had up to an order of magnitude higher glycosaminoglycan contents than their acellular counterparts. Gene expression results indicated a suppressive effect of DCC and CS encapsulation on rat bone marrow stromal cell chondrogenesis with differences in gene expression patterns existing between the DCC and CS groups. Overall, DCC and CS were easily included in microsphere-based scaffolds; however, there is a requirement to further refine their concentrations to achieve the differentiation profiles we seek in vitro. PMID:27358376

Selective Co-Encapsulation Inside an M6 L4 Cage.

PubMed

Leenders, Stefan H A M; Becker, René; Kumpulainen, Tatu; de Bruin, Bas; Sawada, Tomohisa; Kato, Taito; Fujita, Makoto; Reek, Joost N H

2016-10-17

There is broad interest in molecular encapsulation as such systems can be utilized to stabilize guests, facilitate reactions inside a cavity, or give rise to energy-transfer processes in a confined space. Detailed understanding of encapsulation events is required to facilitate functional molecular encapsulation. In this contribution, it is demonstrated that Ir and Rh-Cp-type metal complexes can be encapsulated inside a self-assembled M 6 L 4 metallocage only in the presence of an aromatic compound as a second guest. The individual guests are not encapsulated, suggesting that only the pair of guests can fill the void of the cage. Hence, selective co-encapsulation is observed. This principle is demonstrated by co-encapsulation of a variety of combinations of metal complexes and aromatic guests, leading to several ternary complexes. These experiments demonstrate that the efficiency of formation of the ternary complexes depends on the individual components. Moreover, selective exchange of the components is possible, leading to formation of the most favorable complex. Besides the obvious size effect, a charge-transfer interaction may also contribute to this effect. Charge-transfer bands are clearly observed by UV/Vis spectrophotometry. A change in the oxidation potential of the encapsulated electron donor also leads to a shift in the charge-transfer energy bands. As expected, metal complexes with a higher oxidation potential give rise to a higher charge-transfer energy and a larger hypsochromic shift in the UV/Vis spectrum. These subtle energy differences may potentially be used to control the binding and reactivity of the complexes bound in a confined space. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Protein encapsulation via porous CaCO3 microparticles templating.

PubMed

Volodkin, Dmitry V; Larionova, Natalia I; Sukhorukov, Gleb B

2004-01-01

Porous microparticles of calcium carbonate with an average diameter of 4.75 microm were prepared and used for protein encapsulation in polymer-filled microcapsules by means of electrostatic layer-by-layer assembly (ELbL). Loading of macromolecules in porous CaCO3 particles is affected by their molecular weight due to diffusion-limited permeation inside the particles and also by the affinity to the carbonate surface. Adsorption of various proteins and dextran was examined as a function of pH and was found to be dependent both on the charge of the microparticles and macromolecules. The electrostatic effect was shown to govern this interaction. This paper discusses the factors which can influence the adsorption capacity of proteins. A new way of protein encapsulation in polyelectrolyte microcapsules is proposed exploiting the porous, biocompatible, and decomposable microparticles from CaCO3. It consists of protein adsorption in the pores of the microparticles followed by ELbL of oppositely charged polyelectrolytes and further core dissolution. This resulted in formation of polyelectrolyte-filled capsules with protein incorporated in interpenetrating polyelectrolyte network. The properties of CaCO3 microparticles and capsules prepared were characterized by scanning electron microscopy, microelectrophoresis, and confocal laser scanning microscopy. Lactalbumin was encapsulated by means of the proposed technique yielding a content of 0.6 pg protein per microcapsule. Horseradish peroxidase saves 37% of activity after encapsulation. However, the thermostability of the enzyme was improved by encapsulation. The results demonstrate that porous CaCO3 microparticles can be applied as microtemplates for encapsulation of proteins into polyelectrolyte capsules at neutral pH as an optimal medium for a variety of bioactive material, which can also be encapsulated by the proposed method. Microcapsules filled with encapsulated material may find applications in the field of biotechnology, biochemistry, and medicine.

A new liposome-based gene delivery system targeting lung epithelial cells using endothelin antagonist.

PubMed

Allon, Nahum; Saxena, Ashima; Chambers, Carolyn; Doctor, Bhupendra P

2012-06-10

We formulated a new gene delivery system based on targeted liposomes. The efficacy of the delivery system was demonstrated in in vitro and in vivo models. The targeting moiety consists of a high-affinity 7-amino-acid peptide, covalently and evenly conjugated to the liposome surface. The targeting peptide acts as an endothelin antagonist, and accelerates liposome binding and internalization. It is devoid of other biological activity. Liposomes with high phosphatidyl serine (PS) were specially formulated to help their fusion with the endosomal membrane at low pH and enable release of the liposome payload into the cytoplasm. A DNA payload, pre-compressed by protamine, was encapsulated into the liposomes, which directed the plasmid into the cell's nucleus. Upon exposure to epithelial cells, binding of the liposomes occurred within 5-10 min, followed by facilitated internalization of the complex. Endosomal escape was complete within 30 min, followed by DNA accumulation in the nucleus 2h post-transfection. A549 lung epithelial cells transfected with plasmid encoding for GFP encapsulated in targeted liposomes expressed significantly more protein than those transfected with plasmid complexed with Lipofectamine. The intra-tracheal instillation of plasmid encoding for GFP encapsulated in targeted liposomes into rat lungs resulted in the expression of GFP in bronchioles and alveoli within 5 days. These results suggest that this delivery system has great potential in targeting genes to lungs. Copyright © 2011 Elsevier B.V. All rights reserved.

Polymer Encapsulation of an Amorphous Pharmaceutical by initiated Chemical Vapor Deposition for Enhanced Stability

PubMed Central

2016-01-01

The usage of amorphous solids in practical applications, such as in medication, is commonly limited by the poor long-term stability of this state, because unwanted crystalline transitions occur. In this study, three different polymeric coatings are investigated for their ability to stabilize amorphous films of the model drug clotrimazole and to protect against thermally induced transitions. For this, drop cast films of clotrimazole are encapsulated by initiated chemical vapor deposition (iCVD), using perfluorodecyl acrylate (PFDA), hydroxyethyl methacrylate (HEMA), and methacrylic acid (MAA). The iCVD technique operates under solvent-free conditions at low temperatures, thus leaving the solid state of the encapsulated layer unaffected. Optical microscopy and X-ray diffraction data reveal that at ambient conditions of about 22 °C, any of these iCVD layers extends the lifetime of the amorphous state significantly. At higher temperatures (50 or 70 °C), the p-PFDA coating is unable to provide protection, while the p-HEMA and p-MAA strongly reduce the crystallization rate. Furthermore, p-HEMA and p-MAA selectively facilitate a preferential alignment of clotrimazole and, interestingly, even suppress crystallization upon a temporary, rapid temperature increase (3 °C/min, up to 150 °C). The results of this study demonstrate how a polymeric coating, synthesized directly on top of an amorphous phase, can act as a stabilizing agent against crystalline transitions, which makes this approach interesting for a variety of applications. PMID:27467099

Polymer Encapsulation of an Amorphous Pharmaceutical by initiated Chemical Vapor Deposition for Enhanced Stability.

PubMed

Christian, Paul; Ehmann, Heike M A; Coclite, Anna Maria; Werzer, Oliver

2016-08-24

The usage of amorphous solids in practical applications, such as in medication, is commonly limited by the poor long-term stability of this state, because unwanted crystalline transitions occur. In this study, three different polymeric coatings are investigated for their ability to stabilize amorphous films of the model drug clotrimazole and to protect against thermally induced transitions. For this, drop cast films of clotrimazole are encapsulated by initiated chemical vapor deposition (iCVD), using perfluorodecyl acrylate (PFDA), hydroxyethyl methacrylate (HEMA), and methacrylic acid (MAA). The iCVD technique operates under solvent-free conditions at low temperatures, thus leaving the solid state of the encapsulated layer unaffected. Optical microscopy and X-ray diffraction data reveal that at ambient conditions of about 22 °C, any of these iCVD layers extends the lifetime of the amorphous state significantly. At higher temperatures (50 or 70 °C), the p-PFDA coating is unable to provide protection, while the p-HEMA and p-MAA strongly reduce the crystallization rate. Furthermore, p-HEMA and p-MAA selectively facilitate a preferential alignment of clotrimazole and, interestingly, even suppress crystallization upon a temporary, rapid temperature increase (3 °C/min, up to 150 °C). The results of this study demonstrate how a polymeric coating, synthesized directly on top of an amorphous phase, can act as a stabilizing agent against crystalline transitions, which makes this approach interesting for a variety of applications.

Microfluidic-enhanced 3D bioprinting of aligned myoblast-laden hydrogels leads to functionally organized myofibers in vitro and in vivo.

PubMed

Costantini, Marco; Testa, Stefano; Mozetic, Pamela; Barbetta, Andrea; Fuoco, Claudia; Fornetti, Ersilia; Tamiro, Francesco; Bernardini, Sergio; Jaroszewicz, Jakub; Święszkowski, Wojciech; Trombetta, Marcella; Castagnoli, Luisa; Seliktar, Dror; Garstecki, Piotr; Cesareni, Gianni; Cannata, Stefano; Rainer, Alberto; Gargioli, Cesare

2017-07-01

We present a new strategy for the fabrication of artificial skeletal muscle tissue with functional morphologies based on an innovative 3D bioprinting approach. The methodology is based on a microfluidic printing head coupled to a co-axial needle extruder for high-resolution 3D bioprinting of hydrogel fibers laden with muscle precursor cells (C2C12). To promote myogenic differentiation, we formulated a tailored bioink with a photocurable semi-synthetic biopolymer (PEG-Fibrinogen) encapsulating cells into 3D constructs composed of aligned hydrogel fibers. After 3-5 days of culture, the encapsulated myoblasts started migrating and fusing, forming multinucleated myotubes within the 3D bioprinted fibers. The obtained myotubes showed high degree of alignment along the direction of hydrogel fiber deposition, further revealing maturation, sarcomerogenesis, and functionality. Following subcutaneous implantation in the back of immunocompromised mice, bioprinted constructs generated organized artificial muscle tissue in vivo. Finally, we demonstrate that our microfluidic printing head allows to design three dimensional multi-cellular assemblies with an exquisite compartmentalization of the encapsulated cells. Our results demonstrate an enhanced myogenic differentiation with the formation of parallel aligned long-range myotubes. The approach that we report here represents a robust and valid candidate for the fabrication of macroscopic artificial muscle to scale up skeletal muscle tissue engineering for human clinical application. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Self-assembling peptide amphiphile nanostructures for cancer therapy

NASA Astrophysics Data System (ADS)

Soukasene, Stephen

The application of nanotechnology to cancer therapy shows great promise for reducing the burden of the disease. By virtue of their size, nanoscale objects preferentially accumulate in tumor tissue through an enhanced permeability and retention (EPR) effect. However, to fully overcome the issues that limit current cancer treatments, viable nanostructures must also impart multifunctionality and be fully compatible with their biological surrounds. The self-assembling peptide amphiphile (PA) materials studied extensively in the Stupp Research Group form very biocompatible high aspect ratio nanostructures that meet these criteria. This thesis investigates the development of PA nanostructures designed to treat cancer. We first look to use the PA as a drug delivery vehicle by entrapping a small hydrophobic anti-cancer drug, camptothecin, in the core of the nanostructures. Using a solvent evaporation technique to load the drug into the PA nanofibers, we are able to improve the aqueous solubility of the molecule by nearly 30-fold. TEM and AFM studies show that entrapment of drug molecules does not disrupt the self-assembled morphology of the nanofiber. In vitro and in vivo studies are also conducted to demonstrate the bioactivity of the drug after its entrapment. As a potential platform for novel therapeutics, we next develop techniques for using light irradiation to trigger self-assembly inside the confined space of liposomes. We encapsulate PA monomers that assemble under acidic conditions along with a photoacid generator inside liposomes. Upon exposure to 254 nm light, the PA monomers self assemble inside the liposome to form nanostructures, which we observe through a quick freeze/deep etch technique that allows us to look inside the liposomes by SEM and TEM. Last of all, the development and discovery of epitopes for targeting PA nanostructures to tumors are explored. Using phage display technology we generate two groups of peptide sequences, one of which can potentially target tumor blood vessel formation, while the other is directed toward the ErbB2 receptor, which is over-expressed in certain aggressive breast cancers. Two peptide sequences from the literature that target breast cancer are also incorporated into PA molecules and we assess their biological affinity in vitro and in vivo.

Optofluidic encapsulation and manipulation of silicon microchips using image processing based optofluidic maskless lithography and railed microfluidics.

PubMed

Chung, Su Eun; Lee, Seung Ah; Kim, Jiyun; Kwon, Sunghoon

2009-10-07

We demonstrate optofluidic encapsulation of silicon microchips using image processing based optofluidic maskless lithography and manipulation using railed microfluidics. Optofluidic maskless lithography is a dynamic photopolymerization technique of free-floating microstructures within a fluidic channel using spatial light modulator. Using optofluidic maskless lithography via computer-vision aided image processing, polymer encapsulants are fabricated for chip protection and guiding-fins for efficient chip conveying within a fluidic channel. Encapsulated silicon chips with guiding-fins are assembled using railed microfluidics, which is an efficient guiding and heterogeneous self-assembly system of microcomponents. With our technology, externally fabricated silicon microchips are encapsulated, fluidically guided and self-assembled potentially enabling low cost fluidic manipulation and assembly of integrated circuits.

Photosensitive function of encapsulated dye in carbon nanotubes.

PubMed

Yanagi, Kazuhiro; Iakoubovskii, Konstantin; Matsui, Hiroyuki; Matsuzaki, Hiroyuki; Okamoto, Hiroshi; Miyata, Yasumitsu; Maniwa, Yutaka; Kazaoui, Said; Minami, Nobutsugu; Kataura, Hiromichi

2007-04-25

Single-wall carbon nanotubes (SWCNTs) exhibit resonant absorption localized in specific spectral regions. To expand the light spectrum that can be utilized by SWCNTs, we have encapsulated squarylium dye into SWCNTs and clarified its microscopic structure and photosensitizing function. X-ray diffraction and polarization-resolved optical absorption measurements revealed that the encapsulated dye molecules are located at an off center position inside the tubes and aligned to the nanotube axis. Efficient energy transfer from the encapsulated dye to SWCNTs was clearly observed in the photoluminescence spectra. Enhancement of transient absorption saturation in the S1 state of the semiconducting SWCNTs was detected after the photoexcitation of the encapsulated dye, which indicates that ultrafast (<190 fs) energy transfer occurred from the dye to the SWCNTs.

The demise of plastic encapsulated microcircuit myths

NASA Astrophysics Data System (ADS)

Hakim, E. B.; Agarwal, R. K.; Pecht, M.

1994-10-01

Production of microelectronic devices encapsulated in solid, molded plastic packages has rapidly increased since the early 1980's. Today, millions of plastic-encapsulated devices are produced daily. On the other hand, only a few million hermetic (cavity) packages are produced per year. Reasons for the increased use of plastic-encapsulated packages include cost, availability, size, weight, quality, and reliability. Markets taking advantage of this technology range from computers and telecommunications to automotive uses. Yet, several industries, the military in particular, will not accept such devices. One reason for this reluctance to use the best available commercial parts is a perceived risk of poor reliability, derived from antiquated military specifications, standards, and handbooks; other common justifications cite differing environments; inadequate screens; inadequate test data, and required government audits of suppliers' processes. This paper describes failure mechanisms associated with plastic encapsulation and their elimination. It provides data indicating the relative reliability of cavity and solid-encapsulated packaging, and presents possible approaches to assuring quality and reliability in the procuring and applying this successful commercial technology.

Effect of lecithin and starch on alginate-encapsulated probiotic bacteria.

PubMed

Donthidi, A R; Tester, R F; Aidoo, K E

2010-01-01

The effect of lecithin and starch on viability of alginate encapsulated probiotics was determined at different temperatures. Probiotic organisms (1% v/v>10Log CFU ml(-1)) were encapsulated using alginate (2% w/v), gelatinized starches (2% w/v) and lecithin (0-4% w/v) and stored in sealed containers at 4, 23 and 37 degrees C (to simulate shelf storage conditions). Incorporation of lecithin improved the entrapment efficiency (p < 0.05) and the viability of encapsulated bacteria (p = 0.02). Encapsulated Lactobacillus, Bifidobacterium species and Lactococcus lactis in lecithin containing freeze-dried beads had good survival stability (above 6Log CFU ml(-1)) at 23 degrees C for 12 weeks. The bacteria in the beads showed 6Log survival by the end of 2 weeks at 37 degrees C. Encapsulated L. casei in the alginate beads containing lecithin were also more stable in the yoghurt than the beads without lecithin. SEM analysis of the beads showed an irregular surface for the beads without lecithin.

Biodegradable polymer based encapsulation of neem oil nanoemulsion for controlled release of Aza-A.

PubMed

Jerobin, Jayakumar; Sureshkumar, R S; Anjali, C H; Mukherjee, Amitava; Chandrasekaran, Natarajan

2012-11-06

Azadirachtin a biological compound found in neem have medicinal and pesticidal properties. The present work reports on the encapsulation of neem oil nanoemulsion using sodium alginate (Na-Alg) by cross linking with glutaraldehyde. Starch and polyethylene glycol (PEG) were used as coating agents for smooth surface of beads. The SEM images showed beads exhibited nearly spherical shape. Swelling of the polymeric beads reduced with coating which in turn decreased the rate of release of Aza-A. Starch coated encapsulation of neem oil nanoemulsion was found to be effective when compared to PEG coated encapsulation of neem oil nanoemulsion. The release rate of neem Aza-A from the beads into an aqueous environment was analyzed by UV-visible spectrophotometer (214 nm). The encapsulated neem oil nanoemulsion have the potential for controlled release of Aza-A. Neem oil nanoemulsion encapsulated beads coated with PEG was found to be toxic in lymphocyte cells. Copyright © 2012 Elsevier Ltd. All rights reserved.