Academic literature on the topic 'Encapsulation de cellules'
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Journal articles on the topic "Encapsulation de cellules":
1
El Amrani, Abdelkader, Achour Mahrane, Mohamed Fathi Moussa, and Yacine Boukennous. "Procédé d’encapsulation des modules photovoltaïques type mono-verre." Journal of Renewable Energies 9, no. 1 (April 30, 2006): 37–42. http://dx.doi.org/10.54966/jreen.v9i1.812.
Abstract:
L’une des étapes importante dans l’industrie photovoltaïque réside dans l’encapsulation des cellules solaires. Elle consiste à regrouper des cellules en série ou en parallèle afin de permettre leur utilisation à des tensions et courants pratiques tout en assurant leur isolation électrique et leur protection contre les facteurs extérieurs tels que l’humidité, la pluie, la neige, les poussières, la corrosion, les chocs mécaniques, etc. Nous nous proposons dans le cadre de ce travail de présenter le procédé d’encapsulation que nous avons mis en oeuvre au niveau de l’Unité de Développement de la Technologie du Silicium (UDTS). Nous nous focaliserons plus particulièrement sur le traitement thermique, car il constitue l’étape la plus critique dans le procédé conditionnant par là même la qualité et la fiabilité du module. Ce traitement thermique est conduit en deux temps : la lamination suivie de la polymérisation. A l’issue du traitement thermique, nous obtenons un ensemble compact. Différents tests de réticulation de l’EVA ont été nécessaires afin de déterminer les paramètres technologiques (niveau du vide, pression, température et temps), conduisant à un procédé performant. Ces résultats ont confirmé par les tests effectués au laboratoire européen Joint Research Centre (JRC) d’Ispra (Italie). En outre, nous avons constaté une amélioration des performances électriques du module après encapsulation (gain en courant de l’ordre de 4 à 6 % et gain en puissance de l’ordre de 4 à 7 %), principalement due à l’utilisation d’un verre traité en surface permettant le piégeage de la lumière incidente réduisant ainsi la réflexion à moins de 8 %.
2
Fukuta, Tatsuya, Mayumi Ikeda-Imafuku, Satoshi Kodama, Junko Kuse, Ko Matsui, and Yasunori Iwao. "One-Step Pharmaceutical Preparation of PEG-Modified Exosomes Encapsulating Anti-Cancer Drugs by a High-Pressure Homogenization Technique." Pharmaceuticals 16, no. 1 (January 11, 2023): 108. http://dx.doi.org/10.3390/ph16010108.
Abstract:
The use of exosomes encapsulating therapeutic agents for the treatment of diseases is of increasing interest. However, some concerns such as limited efficiency and scalability of conventional drug encapsulation methods to exosomes have still remained; thus, a new approach that enables encapsulation of therapeutic agents with superior efficiency and scalability is required. Herein, we used RAW264 macrophage cell-derived exosomes (RAW-Exos) and demonstrated that high-pressure homogenization (HPH) using a microfluidizer decreased their particle size without changing their morphology, the amount of exosomal marker proteins, and cellular uptake efficiency into RAW264 and colon-26 cancer cells. Moreover, HPH allowed for modification of polyethylene glycol (PEG)-conjugated lipids onto RAW-Exos, as well as encapsulation of the anti-cancer agent doxorubicin. Importantly, the doxorubicin encapsulation efficiency became higher upon increasing the process pressure and simultaneous HPH with PEG-lipids. Moreover, treatment with PEG-modified RAW-Exos encapsulating doxorubicin significantly suppressed tumor growth in colon-26-bearing mice. Taken together, these results suggest that HPH using a microfluidizer could be useful to prepare PEG-modified Exos encapsulating anti-cancer drugs via a one-step pharmaceutical process, and that the prepared functional Exos could be applied for the treatment of cancer in vivo.
3
Guerrero, Rodel, Paul W. S. Heng, and Terence P. Tumolva. "Preparation of Crosslinked Alginate-Cellulose Derivative Microparticles for Protein Delivery." Key Engineering Materials 931 (September 9, 2022): 69–75. http://dx.doi.org/10.4028/p-o7266l.
Abstract:
Microparticle protein delivery system using alginate and cellulose derivative (HPC, HEC and CMC) composite system was prepared using external gelation with vibration technology. Bovine serum albumin (BSA) as a model protein was encapsulated using these biodegradable materials. This preparation showed an increase in encapsulation efficiency in comparison to the samples where pure alginate was used as the encapsulating material. Compared with the other microparticles, the 50:50 alginate/HEC samples exhibited significant encapsulation efficiency. Consequently, its release rate in the acidic medium was comparatively substantial and higher cumulative release in the simulated intestinal fluid (SIF) medium at the end of the dissolution study was observed to be high at around 86.17%.
4
Gonçalves, Antónia, Fernando Rocha, and Berta N. Estevinho. "Application of Ethyl Cellulose and Ethyl Cellulose + Polyethylene Glycol for the Development of Polymer-Based Formulations using Spray-Drying Technology for Retinoic Acid Encapsulation." Foods 11, no. 16 (August 22, 2022): 2533. http://dx.doi.org/10.3390/foods11162533.
Abstract:
Ethyl cellulose (EC)-based microparticles, with and without the incorporation of polyethylene glycol (PEG) as a second encapsulating agent, were prepared using the spray-drying process for the encapsulation of retinoic acid (RA). The production of a suitable controlled delivery system for this retinoid will promote its antitumor efficiency against acute promyelocytic leukemia (APL) due to the possibility of increasing the bioavailability of RA. Product yield ranged from 12 to 28% in all the microparticle formulations, including unloaded microparticles and RA-loaded microparticles. Microparticles with a mean diameter between 0.090 ± 0.002 and 0.54 ± 0.02 µm (number size distribution) and with an irregular form and rough surface were obtained. Furthermore, regarding RA-loaded microparticles, both polymer-based formulations exhibited an encapsulation efficiency of around 100%. A rapid and complete RA release was reached in 40 min from EC− and EC + PEG-based microparticles.
5
Yang, Ying, Junze Zhang, and Chengcheng Li. "Delivery of Probiotics with Cellulose-Based Films and Their Food Applications." Polymers 16, no. 6 (March 13, 2024): 794. http://dx.doi.org/10.3390/polym16060794.
Abstract:
Probiotics have attracted great interest from many researchers due to their beneficial effects. Encapsulation of probiotics into biopolymer matrices has led to the development of active food packaging materials as an alternative to traditional ones for controlling food-borne microorganisms, extending food shelf life, improving food safety, and achieving health-promoting effects. The challenges of low survival rates during processing, storage, and delivery to the gut and low intestinal colonization, storage stability, and controllability have greatly limited the use of probiotics in practical food-preservation applications. The encapsulation of probiotics with a protective matrix can increase their resistance to a harsh environment and improve their survival rates, making probiotics appropriate in the food packaging field. Cellulose has attracted extensive attention in food packaging due to its excellent biocompatibility, biodegradability, environmental friendliness, renewability, and excellent mechanical strength. In this review, we provide a brief overview of the main types of cellulose used for probiotic encapsulation, as well as the current advances in different probiotic encapsulating strategies with cellulose, grafted cellulose, and cellulose-derived materials, including electrospinning, cross-linking, in-situ growth, casting strategies, and their combinations. The effect of cellulose encapsulation on the survival rate of probiotics and the patented encapsulated probiotics are also introduced. In addition, applications of cellulose-encapsulated probiotics in the food industry are also briefly discussed. Finally, the future trends toward developing encapsulated probiotics with improved health benefits and advanced features with cellulose-based materials are discussed.
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Sánchez-Osorno, Diego Mauricio, Angie Vanesa Caicedo Paz, María Camila López-Jaramillo, Aída Luz Villa, and Julián Paul Martínez-Galán. "Protection of Mono and Polyunsaturated Fatty Acids from Grapeseed Oil by Spray Drying Using Green Biopolymers as Wall Material." Foods 11, no. 24 (December 7, 2022): 3954. http://dx.doi.org/10.3390/foods11243954.
Abstract:
One of the most common ways to protect oils is microencapsulation, which includes the use of encapsulating agents. Due to the environmental problems facing humanity, this study seeks to combine green biopolymers (microcrystalline cellulose and whey protein isolate) that function as encapsulating agents for grapeseed oil. Grapeseed oil that is obtained from agro-industrial waste has shown health benefits, including cardioprotective, anticancer, antimicrobial, and anti-inflammatory properties. These health benefits have been mainly associated with monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. In this sense, it has been observed that grapeseed oil can be easily modified by environmental factors such as oxygen, high temperatures, and light, showing the instability and easy degradation of grapeseed oil. In this study, grapeseed oil was encapsulated using the spray-drying technique to conserve its lipidic profile. Powder recovery of the grapeseed oil microcapsules ranged from 65% to 70%. The encapsulation efficiency of the microcapsules varied between 80% and 85%. The FTIR analysis showed chemical interactions that demonstrate chemisorption between the grapeseed oil and the encapsulating material, while the SEM micrographs showed a correct encapsulation in a spherical shape. Gas chromatography showed that the lipid profile of grapeseed oil is preserved thanks to microencapsulation. Release tests showed 80% desorption within the first three hours at pH 5.8. Overall, whey protein and microcrystalline cellulose could be used as a wall material to protect grapeseed oil with the potential application of controlled delivery of fatty acids microcapsules.
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Clapacs, Zain, Sydney Neal, David Schuftan, Xiaohong Tan, Huanzhu Jiang, Jingxuan Guo, Jai Rudra, and Nathaniel Huebsch. "Biocompatible and Enzymatically Degradable Gels for 3D Cellular Encapsulation under Extreme Compressive Strain." Gels 7, no. 3 (July 24, 2021): 101. http://dx.doi.org/10.3390/gels7030101.
Abstract:
Cell encapsulating scaffolds are necessary for the study of cellular mechanosensing of cultured cells. However, conventional scaffolds used for loading cells in bulk generally fail at low compressive strain, while hydrogels designed for high toughness and strain resistance are generally unsuitable for cell encapsulation. Here we describe an alginate/gelatin methacryloyl interpenetrating network with multiple crosslinking modes that is robust to compressive strains greater than 70%, highly biocompatible, enzymatically degradable and able to effectively transfer strain to encapsulated cells. In future studies, this gel formula may allow researchers to probe cellular mechanosensing in bulk at levels of compressive strain previously difficult to investigate.
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Wardhani, Dyah H., Heri Cahyono, Hana N. Ulya, Andri C. Kumoro, Khairul Anam, and José Antonio Vázquez. "Spray-dryer feed preparation: Enzymatic degradation of glucomannan for iron nanoencapsulation." AIMS Agriculture and Food 7, no. 3 (2022): 683–703. http://dx.doi.org/10.3934/agrfood.2022042.
Abstract:
<abstract> <p>Viscosity of glucomannan (GM) needs to be modified to support its application for spray drying encapsulation. The purpose of this study was to investigate degradation of GM using cellulase that fulfills viscosity in a spray-dryer specification. This hydrolyzed glucomannan (HGM) was subsequently spray-dried for encapsulating iron. Lower initial GM concentrations (0.5–1%) reached approximately 0.30 Pa·s which allowed to be spray-dried after 100 min degradation using 10 mg/L cellulase. Meanwhile, viscosity of 1.5% and 1.7% GM did not reach the target viscosity even after 300 min. The n<sup>th</sup>-order model was the most suitable model which fitted viscosity reduction of ≤1.5% initial GM concentration (coefficient of determination, R<sup>2</sup> > 0.98), whereas the Mahammad model fitted the viscosity reduction of 1.75% initial GM concentration (R<sup>2</sup> = 0.99). Hydrolysis decreased the degree of polymerization and surface tension but increased the antioxidant activities of HGM. Smaller molecules of the polysaccharides were released after hydrolysis. Particles of encapsulated iron using HGM were more hydrophilic than those using GM. The iron tended to have a higher release rate at pH 6.8 than at pH 1.2 in the first 40 min. Hence, the HGM showed its ability to act as a control release matrix for the iron that needs a protection in the acid environment, and delivers them to the neutral site for absorption. Nanoencapsulation using 0.35 Pa·s viscosity of HGM was able to have 84% yield, 96.41% encapsulation efficiency, and 10% moisture content. Particle size of the iron encapsulation was dominated by 341.99 nm-diameter. This study shows a potency to use an appropriate viscosity of HGM which not only allows to be spray-dried but also support in protecting the iron as aimed by encapsulation the iron. Performances and properties of this matrix on encapsulating other bioactive compounds become future study.</p> </abstract>
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Yang, Yen-Ching, Wei-Shen Huang, Shu-Man Hu, Chao-Wei Huang, Chih-Hao Chiu, and Hsien-Yeh Chen. "Synergistic and Regulatable Bioremediation Capsules Fabrication Based on Vapor-Phased Encapsulation of Bacillus Bacteria and its Regulator by Poly-p-Xylylene." Polymers 13, no. 1 (December 24, 2020): 41. http://dx.doi.org/10.3390/polym13010041.
Abstract:
A regulatable bioremediation capsule material was synthesized with isolated single-strain bacteria (Bacillus species, B. CMC1) and a regulator molecule (carboxymethyl cellulose, CMC) by a vapor-phased encapsulation method with simple steps of water sublimation and poly-p-xylylene deposition in chemical vapor deposition (CVD) process. Mechanically, the capsule construct exhibited a controllable shape and dimensions, and was composed of highly biocompatible poly-p-xylylene as the matrix with homogeneously distributed bacteria and CMC molecules. Versatility of the encapsulation of the molecules at the desired concentrations was achieved in the vapor-phased sublimation and deposition fabrication process. The discovery of the fabricated capsule revealed that viable living B. CMC1 inhabited the capsule, and the capsule enhanced bacterial growth due to the materials and process used. Biologically, the encapsulated B. CMC1 demonstrated viable and functional enzyme activity for cellulase activation, and such activity was regulatable and proportional to the concentration of the decorated CMC molecules in the same capsule construct. Impressively, 13% of cellulase activity increase was realized by encapsulation of B. CMC1 by poly-p-xylylene, and a further 34% of cellulase activity increase was achieved by encapsulation of additional 2.5% CMC. Accordingly, this synergistic effectiveness of the capsule constructs was established by combining enzymatic B. CMC1 bacteria and its regulatory CMC by poly-p-xylylene encapsulation process. This reported encapsulation process exhibited other advantages, including the use of simple steps and a dry and clean process free of harmful chemicals; most importantly, the process is scalable for mass production. The present study represents a novel method to fabricate bacteria-encapsulated capsule for cellulose degradation in bioremediation that can be used in various applications, such as wastewater treatment and transforming of cellulose into glucose for biofuel production. Moreover, the concept of this vapor-phased encapsulation technology can be correspondingly used to encapsulate multiple bacteria and regulators to enhance the specific enzyme functions for degradation of various organic matters.
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Kim, Ma Rie, Teng Feng, Qian Zhang, Ho Yin Edwin Chan, and Ying Chau. "Co-Encapsulation and Co-Delivery of Peptide Drugs via Polymeric Nanoparticles." Polymers 11, no. 2 (February 8, 2019): 288. http://dx.doi.org/10.3390/polym11020288.
Abstract:
Combination therapy is a promising form of treatment. In particular, co-treatment of P3 and QBP1 has been shown to enhance therapeutic effect in vivo in treating polyglutamine diseases. These peptide drugs, however, face challenges in clinical administration due to poor stability, inability to reach intracellular targets, and lack of method to co-deliver both drugs. Here we demonstrate two methods of co-encapsulating the peptide drugs via polymer poly(ethylene glycol)-block-polycaprolactone (PEG-b-PCL) based nanoparticles. Nanoparticles made by double emulsion were 100–200 nm in diameter, with drug encapsulation efficiency of around 30%. Nanoparticles made by nanoprecipitation with lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (POPG) were around 250–300 nm in diameter, with encapsulation efficiency of 85–100%. Particles made with both formulations showed cellular uptake when decorated with a mixture of peptide ligands that facilitate endocytosis. In vitro assay showed that nanoparticles could deliver bioactive peptides and encapsulation by double emulsion were found to be more effective in rescuing cells from polyglutamine-induced toxicity.
Dissertations / Theses on the topic "Encapsulation de cellules":
1
Geisler, Hubert. "Structuration d'hydrogels thermoactivables pour l'analyse de cellules uniques." Electronic Thesis or Diss., Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLS001.
Abstract:
Dans cette thèse est présentée une nouvelle technologie microfluidique de capture de cellules uniques basée sur l’utilisation d’hydrogels thermoactivables. Nous utilisons notamment le PolyNIPAM, un polymère dont le volume est augmenté dans l'eau de 400% lorsque la température est inférieure à 32°C et est dégonflé lorsque la température est supérieure à 34°C. Nous exploitons ce gonflement réversible pour ouvrir et fermer des compartiments intégrés dans une chambre microfluidique.Le greffage et la structuration de ces motifs d’hydrogel repose sur la chimie click thiol-ène, initiée par voie thermique ou par irradiation UV. Nous avons développé des méthodes et procédés de microfabrication dans le but de diversifier les substrats d’accroche (du verre vers le PDMS, COC, PMMA, etc), d’élargir la gamme des épaisseurs des structures réalisables (de quelques microns vers la dizaine de microns d’épaisseur) et de renforcer nos connaissances concernant l'incidence de la fabrication sur le comportement de l’hydrogel. Un protocole de photolithographie robuste est finalement obtenu permettant le design de toute sorte de motif 2D sur différents choix de substrat. Une application possible détaillée par la suite est le développement de ces puces microfluidiques capables de capturer des cellules uniques dans des compartiments en hydrogel. (confidentiel)We present in this work a new microfluidic technology aiming at isolating single cells by the use of thermoactuable polymers. One of the polymers we use is polyNIPAM, a polymer that can expand its volume by 400% in water when the temperature is set under 32°C and can shrink down when it is set over 34°C. We use this reversible swelling capability to open and close compartments embedded in a microfluidic chip.Grafting and structuring these hydrogel features relies on thiol-en click chemistry, initiated thermally or by UV irradiation. We have developed methods and microfabrication protocols in order to diversify the substrate materials (from glass to PDMS, COC, PMMA, etc), to expand the structures thickness range (from few microns to a tenth of microns) and to strengthen our knowledge regarding the fabrication impact on the hydrogel’s behavior. A robust protocol of photolithography has finally been worked on allowing the design of any type of 2D features on a large choice of substrates.One of the realistic applications detailed here is the development of microfluidic chips aiming at isolating single cells in hydrogel compartments. (confidential)
2
Le, Vot-Morales Sophie. "Microsystème pour l’encapsulation de cellules pancréatiques." Université Joseph Fourier (Grenoble ; 1971-2015), 2009. http://www.theses.fr/2009GRE10191.
Abstract:
Le but de ce travail de recherche est de concevoir un microsystème permettant l’encapsulation d’îlots de Langerhans, amas de cellules pancréatiques dont la fonction principale est la régulation de la glycémie. L’encapsulation permet de réduire la dose de traitement immunosuppresseur administrée lors d’une transplantation. Les cellules encapsulées sont en effet protégées du système immunitaire du receveur par la capsule de polymère. À l’heure actuelle, les principaux challenges des techniques d’encapsulation sont l’automatisation de la procédure, mais aussi le contrôle précis de la taille, polydispersité et forme des capsules. L’objectif principal de ce travail a été d’évaluer les potentialités de la microfluidique comme nouvelle technique d’encapsulation. L’encapsulant choisi dans cette étude est le polymère le plus couramment utilisé pour l’encapsulation de cellules, à savoir l’alginate. La formation d’émulsions d’alginate en flux continu a été analysée, en utilisant une géométrie de type MFFD « Microfluidic flow focusing device ». L’influence de la viscosité et de la viscoélasticité des solutions d’alginate sur la formation d’émulsions en microsystème a été caractérisée. Les gouttes d’alginate produites en flux doivent ensuite être gélifiées. Une nouvelle géométrie de gélification en microsystème a été développée et comparée aux techniques existantes. L’un des défis de la gélification sur puce est la conservation de la forme sphérique des capsules, tout en opérant dans des conditions non létales pour les cellules (pH7,4). Les différents microsystèmes développés ont permis la production de capsules de diamètre compris entre 50 m et 1 mm. Les premières encapsulations d’îlots de Langerhans en microsystème ont pu être réaliséesThis study is devoted to the development of a microfluidic system for the encapsulation of islets of Langerhans. These clusters of cells secrete a pancreatic hormone (insulin) in order to regulate the blood glucose level. Encapsulation allows a considerable reduction in the amount of immunosuppressive therapy since the polymer capsule isolates the transplanted cells from the immune system. Major challenge for cell encapsulation are now to automate the encapsulation process and to control accurately the size, the polydispersity, and the shape of the capsules. The main purpose of this study was to evaluate the potential of microfluidics as a new technology for cell encapsulation. The immobilization material selected in this study is the alginate since it is the most commonly used polymer for cell encapsulation. Using a flow focusing geometry (MFFD), alginate droplet formation in an oil flow is characterized. Influence of viscosity and viscoelasticity of alginate solutions on droplet pinch-off is scrutinized. The gelling of alginate droplet has been investigated. A new gelling process has been developed, and its advantages on the classical gelation methods are discussed. It is recalled that the main challenges of the gelation on chip are to maintain the spherical shape of the capsules, and to respect the cell viability (pH7,4). Using the microfluidic devices that have been produced. Encapsulations of islets of Langerhans have been performed
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Morlier, Arnaud. "Propriétés barrières de structures hybrides. Application à l'encapsulation des cellules solaires." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENI056.
Abstract:
Les matériaux utilisés pour diverses applications en électronique organique ou photovoltaïque denouvelle génération subissent des dégruvent être encapsulés à l’aide de matériaux barrière àl’oxygène et à l’eau. Pour l’encapsulation des cellules photovoltaïques organiadations sous les effets conjugués de l’eau et de l’oxygène. Afinde limiter cette dégradation, ces dispositifs peques, les perméabilités àl’eau (WVTR) et à l’oxygène (OTR) de l’encapsulant ne doivent pas excéder 10-3 g.m-2.j-1 et 10-3cm3.m-2.j-1 respectivement.L’objectif de ce travail de thèse est l’étude et l’élaboration par voie humide d’une structuremulticouche hybride organique/inorganique flexible, transparente et barrière aux gaz ainsi que lacompréhension des mécanismes permettant de limiter la diffusion des gaz au travers de cette structure.Dans un premier temps, le travail de thèse a été consacré à la réalisation d’une couche mince d’oxydede silicium sur substrat polymère à partir d’un précurseur inorganique : le perhydropolysilazane(PHPS). Différentes voies de conversion du précurseur ont été étudiées et comparées. Lesperméabilités à l’eau et à l’oxygène des meilleures couches déposées sur substrat polymère sont del’ordre de 0,1 g.m-2.j-1 et 0,1 cm3.m-2.j-1 respectivement. Ces valeurs sont comparables à cellesobtenues pour des dépôts réalisés par voie plasma.Des structures multicouches hybrides ont été réalisées en intercalant des couches de polymère entredes couches d’oxyde de silicium afin de décorréler les défauts des couches denses. Cela a permisd’atteindre des perméabilités inférieures ou égales à 10-2 g.m-2.j-1 à l’eau et de l’ordre de 10-3 cm3.m-2.j-1 à l’oxygène.Les performances au cours du temps sous irradiation de cellules solaires encapsulées ont étécomparées. L’encapsulation avec le meilleur matériau barrière développé confère une stabilitéremarquable aux cellules.Cette étude a ainsi permis de montrer les structures barrières élaborées par voie liquide constituent unealternative de choix pour l’encapsulation à grande échelle de cellules photovoltaïquesMaterials used in organic electronic devices or new generation photovoltaics undergo degradation byoxygen and water. In order to prevent their degradation, the devices should be encapsulated withmaterials showing a low permeability to oxygen and water vapor. For organic solar cellsencapsulation, material permeability to water (WVTR) and oxygen (OTR) should not exceed 10-3 g.m-2.d-1 and 10-3 cm3.m-2.d-1 respectively. The aim of this work is to study and develop a solutionprocessed,flexible, transparent and gas-barrier multilayer inorganic/organic hybrid structure, and tounderstand the mechanisms involved in diffusion limitation through these barriers.Firstly, this work has been dedicated to the realization on a polymer substrate of a thin silicon oxidelayer from an inorganic precursor: the perhydropolysilazane (PHPS). Different precursor conversionpaths have been studied and compared. The best barrier layers on polymer substrate have shownoxygen and water permeabilities of about 0,1 g.m-2.d-1 and 0,1 cm3.m-2.d-1 respectively. This result iscomparable to the permeability of plasma deposited layers.Multilayer hybrid structures have been realized by introducing a polymer layer between inorganiclayers in order to decorrelate the thin layer defects. This achieved permeabilities below 10-2 g.m-2.d-1for water and 10-3 cm3.m-2.d-1 for oxygen.The photovoltaic performances of encapsulated organic solar cells under illumination have beencompared over time. Encapsulation with the best barrier material developed during this work resultedin good device stability.This study has shown that entirely solution-processed barrier materials are a promising option for largescale organic solar cells encapsulation
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Berthuy, Ophélie. "Puce à cellules multiplexée pour l'étude de réponses cellulaires parallélisées." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10133/document.
Abstract:
Les travaux présentés dans cette thèse concernent le développement d'une puce à cellules multiplexée pour l'étude de réponses cellulaires parallélisées. La lignée de cellules issues de cancer de la prostate, les cellules LNCaP, ont servi de modèle d'étude grâce à leur capacité à sécréter l'antigène prostate-spécifique (PSA) et la β-2-microglobuline (B2M) en réponse à l'induction par des hormones telles que la dihydrotestostérone (DHT). Nous avons ainsi pu détecter en temps réel et sans marquage ces molécules lors de leur sécrétion par de petites populations de cellules LNCaP adhérentes (de 1 à 100 cellules) à des positions déterminées sur une biopuce SPRi. Trois approches différentes ont été envisagées pour cette biopuce. La première consistait à microtexturer la surface d'or d'un support de SPRi afin d'obtenir des micropuits dont le fond révèle la surface d'or (région cytophile) et dont l'extérieur est composé de polystyrène (cytophobe) afin de créer un contraste d'adhésion pour la culture cellulaire. Des anticorps ont pu être immobilisés de façon contrôlée dans les micropuits grâce à un automate de micro-dépôt non contact. Dans ce système miniaturisé, différentes lignées cellulaires ont pu être co-cultivées sur une surface de 1 cm², ouvrant la voie au multiplexage. Une petite population de cellules (de 1 à 100) a été déposée de façon automatisée dans chaque micropuits. Afin de maintenir les cellules dans un milieu hydraté au cours du dépôt, un polymère d'alginate biocompatible a été utilisé. Cette méthode permet l'encapsulation de cellules dans un très petit volume (< 50 nL). La capacité de cet hydrogel à maintenir les cellules encapsulées à une position donnée sur le support a conduit à la conception d'une deuxième approche pour la fabrication de la biopuce. En effet dans cette approche la surface n'est pas modifiée et les composés biologiques (anticorps et cellules) sont directement déposés de façon automatisée sur la couche d'or. Enfin une dernière approche a été développée en immobilisant cette fois-ci les cellules sur un support microtexturé placé en face de la couche sensible de SPRi. Dans les trois approches, les cinétiques de sécrétion du PSA et de la B2M sécrétées ont pu être suivies par SPRiThe work reported in this thesis focuses on the development of a multiplexed cell chip for the study of parallelized cellular responses. The lineage of cells from Prostate cancer LNCaP cells, were used as a study model thanks to their ability to secrete prostate-specific antigen (PSA) and β-2-microglobulin (B2M) in response to induction by hormones such as dihydrotestosterone (DHT). We were able to detect in real time these label-free molecules and their secretion by small populations of adherent LNCaP cells (from 1 to 100 cells) at specified positions on a SPRi biochip. Three different approaches were considered for this biochip. The first was to pattern the gold surface of a SPRi slide to obtain microwells whose bottom reveals the gold surface (cytophilic area) and an outer shell composed of polystyrene (cytophobe) to create an adhesive/non-adhesive surface for cell culture. Antibodies were immobilized in a controlled manner in the microwells using a piezo electric spotter. In this miniaturized system, different cell lines were co-cultured on a surface of 1 cm², paving the way for multiplexing. A small population of cells (1 to 100) was deposited in an automated manner into each microwell. In order to maintain the cells in a hydrated environment during deposition, a biocompatible alginate polymer was used. This method allows the encapsulation of cells in a very small volume (<50 nL). The ability of the hydrogel to maintain the encapsulated cells in a given position on the support led to the design of a second approach for the production of the biochip. In this second approach the surface is not altered and biological compounds (antibodies and cells) are directly deposited in an automated manner on the gold layer. Finally, a last approach was developed by immobilizing the cells on a patterned substrate placed in front of the sensitive layer SPRi. In all three approaches, the kinetics of PSA secretion and secreted B2M could be followed by SPRi
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Gaume, Julien. "Etude du photovieillissement de matériaux nanocomposites pour l'encapsulation de cellules solaires organiques." Thesis, Clermont-Ferrand 2, 2011. http://www.theses.fr/2011CLF22173.
Abstract:
Ce travail est consacré à l‟étude de la stabilité photochimique de nanocomposites polymère / argile en vue de leur insertion dans un système multicouche organique / inorganique pour l‟encapsulation des cellules solaires organiques. L‟objectif est d‟obtenir des films de nanocomposites polymère / argile flexibles, transparents, pouvant être mis en oeuvre par voie liquide, et photochimiquement stables. Dans une première partie, la caractérisation de nanocomposites à base d‟alcool polyvinylique (PVA) a montré leur aptitude à être insérés dans un système multicouche, notamment en ce qui concerne les propriétés barrière aux gaz. L‟étude du comportement photochimique du PVA basée sur l‟identification des produits de dégradation a permis de proposer un mécanisme de photooxydation du PVA et de déterminer les effets du photovieillissement sur les propriétés du film (rugosité, perméabilité, transparence). L‟insertion de nanocharges lamellaires (Montmorillonite, Laponite ou Hydroxydes Doubles Lamellaires) dans le PVA induit des effets différents (prodégradant ou stabilisant) en fonction de la nature de l‟argile (naturelle ou synthétique). Cependant, lors d‟irradiations en absence d‟oxygène, le PVA et les nanocomposites PVA / argile sont très stables. Enfin, l‟encapsulation alternant couche inorganique SiOx et couche organique PVA ou nanocomposite PVA / argile, permet d‟atteindre les niveaux de perméation requis pour les cellules solaires organiques pour des applications nomadesThis work was devoted to the study of the photochemical behavior of polymer / clay nanocomposites with the aim to use these nanocomposites in a multilayer organic / inorganic coating for organic solar cells encapsulation. The goal of this work was to obtain polymer / clay nanocomposite films that are flexible, transparent, which can be processed by solution, and that are photochemically stable. In the first part, the characterization of nanocomposites based on polyvinyl alcohol (PVA) has shown their ability to be inserted into a multilayer system, particularly for gas barrier properties. The study of the photochemical behavior of PVA with the identification of photodegradation products allows us to propose a photooxidation mechanism of PVA and to determine the effects of photoageing on the film properties (roughness, permeability, transparency). The insertion of lamellar nanofillers (Montmorillonite, Laponite or Layered Double Hydroxide) in PVA induces different effects (prodegradant or stabilising) depending on the nature of the clay (natural or synthetic). However, in absence of oxygen, the PVA and PVA / clay nanocomposites are very photostable. Finally, encapsulation alternating inorganic SiOx layer and PVA or PVA / clay nanocomposite layer permits to obtain the permeability levels required for organic solar cells in niche markets (consumer electronics)
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Dalle, Prisca. "Système intégré pour l'encapsulation monocouche de cellules." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENS036/document.
Abstract:
L'implantation d'îlots de Langerhans microencapsulés est une thérapie prometteuse pour le diabète de type 1. Le concept est de rétablir la fonction de sécrétion d'insuline tout en évitant le rejet de greffe. Les premiers essais cliniques ont reporté des résultats encourageants mais encore peu reproductibles. En effet, les techniques actuelles de production de microcapsules sont manuelles et au sein d'un même lot les capsules ne sont pas homogènes. L'utilisation de la microfluidique offre la possibilité de remédier à ce problème. Ce projet présente les différentes étapes d'optimisation d'un système microfluidique complexe qui automatise le procédé d'encapsulation monocouche de cellules dans des capsules polymériques d'alginate. Ce système comporte trois fonctions principales en série : la formation de gouttes monodisperses d'alginate en flux d'huile par un module MFFD (Micro Flow Focusing Device), le transfert de ces gouttes de la phase huileuse vers une phase aqueuse gélifiante de calcium et enfin un second transfert vers un flux à concentration physiologique. Des capsules monodisperses et sphériques ont été obtenues en sortie de ce système et des premiers tests d'encapsulation de cellules ont été réalisés. Les capsules produites par le système automatisé ont conduit à une première implantation chez le rongeur. Ce système est une première étape clé vers un dispositif instrumenté qui permettrait aux cliniciens d'encapsuler des îlots rapidement et de façon reproductible directement après leur isolement, puis de les implanter chez les patients diabétiques. Mots clés : encapsulation, îlots de Langerhans, alginate, gélification, microfluidique, automatisation, MFFD, transfert de phaseEpileptic seizures arise from pathological synchronization of neuronal ensemble.Seizures originating from primary motor cortex are often pharmacoresistant, and many times unsuitable for respective surgery because of location of epileptic focus in eloquent area. Basal ganglia play important role in seizure propagation. Micro electrode recordings performed during previous studies indicated that input structures of basal ganglia such as GPe, Putamen and Subthalamic nucleus (STN) are strongly modified during seizures. For example the mean firing rate of neurons of the STN and Putamen increased and the percentage of oscillatory neurons synchronized with the ictal EEG was higher during seizures as compared to interictal periods. Pilot studies in humans have shown the possible beneficial effect of chronic DBS applied to STN in treatment of pharmacoresistant motor seizures. Our study was aimed at studying the therapeutic effect of electrical stimulation of input structures of basal ganglia . We first developed a stable, predictable primate model of focal motor epilepsy by intracortical injection of penicillin and we documented it's pharmacoresistence. We then stereotactically implanted DBS electrodes in the STN and Putamen. The stimulator was embedded at the back of the animals. Subthreshold electrical stimulations at 130 Hz were applied to STN. Stimulator was turned ON when penicillin was injected. Sham stimulation at 0 volt was used as a control situation, each monkey being its own control. The time course, number and duration of seizures occurring in each epochs of 1 h were compared during ON and sham stimulation periods. Each experimental session lasted uptoo 6 hours,We also studied preventive high frequency stimulation of STN and subthershold low frequency stimulation of Putamen with 5 Hz and 20 Hz in the same model .Finally we studied combined effects of high frequency STN and low frequency Putamen stimulation in one monkey Results: Data was analysed from 1572 seizures in 30 experiments in three monkeys for chronic STN stimulation , 454 seizures in 10 experiments in one moneky during preventive STN stimulation ,289 seizures from 14 experiments in two monkeys during LFS putamen stimulation and 477 seizures from 10 sessions during combined STN and Putamen stimulation in one monkey The best results were observed during chronic STN stimulation The occurrence of first seizure was significantly delayed as compared to sham situation. Total time spent in focal seizures was significantly reduced by ≥69% on an average (p ≤0.05) after STN stimulation, due to a significant decrease in the number of seizures especially so during the first 3 hours after stimulation. The duration of individual seizures reduced moderately. Bipolar and monopolar stimulation modes were equally effective Preventive HFS STN (in one specimen) was not found to be superior to acute stimulation. LFS Putamen alone was effective but mainly in first two hours of stimulation .In a combined HFS STN and LFS Putamen stimulation the effect of stimulation in terms of seizure control was modest and poor compared to HFS STN alone or LFS Putamen alone. This study provides original data in primates showing the potential therapeutic effect of chronic HFS-STN DBS to treat focal motor seizures . A discussion explaining these
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Authesserre, Claire. "Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAS017.
Abstract:
La transplantation de microcapsules contenant des îlots de Langerhans, amas de cellules pancréatiques régulant la glycémie, montre des résultats prometteurs dans le traitement du diabète de type 1. A l’heure actuelle, il existe encore de nombreux challenges pour augmenter la durabilité d’une greffe fonctionnelle. Le manque de standardisation des technologies d’encapsulation actuelles a suscité un intérêt pour les technologies d’encapsulation microfluidique permettant d’apporter précision et automatisation. Cette thèse s’est attachée à faire progresser deux points de limitations actuelles de ces techniques : la productivité du système et l’état de surface des capsules obtenues.Dans la première partie, nous nous sommes concentrés sur la caractérisation d’un système microfluidique de génération de gouttes à focalisation d’écoulement (MFFD), contrôlé en pression. Des modèles analytiques et numériques ont été développés afin de déterminer les écoulements dans le système. Ensuite, la formation de gouttes a été caractérisée en fonction des paramètres d’entrée du système. Cette étude a abouti à l’obtention de lois permettant de prédire ces paramètres d’entrée afin d’optimiser la fréquence de production de microcapsules d’alginate.Dans la deuxième partie, nous avons développé un système microfluidique permettant de former des capsules de type cœur-couche, afin d’optimiser l’état de surface des capsules. Des premiers essais d’encapsulation d’îlots de Langerhans ont montré le potentiel de ce système dans la minimisation d’une réaction immunitaire vis-à-vis de ces capsules.Ce travail est un premier pas vers l’optimisation du système d’encapsulation, qui à terme, permettra de fournir aux cliniciens des capsules répondant à tous les critères exigés pour la transplantationTransplantation of microcapsules containing pancreatic islets, cell clusters regulating blood sugar, show promising results for type 1 diabetes therapy. However, many challenges remain to improve long-term graft functionality. The lack of standardization of current encapsulation technologies has aroused interest in microfluidic systems that enable more precision and automation.This thesis focuses on two of the current encapsulation technologies stakes: improving system productivity and microcapsules surface.In the first part of this thesis, we characterized a pressure-driven microfluidic flow focusing device (MFFD) droplet generation system. Analytical and numerical models were developed in order to determine and predict flow rates. Droplet formation was characterized as a function of the system input parameters. This study led to scaling laws enabling to predict these system input parameters in order to optimize alginate microcapsules production frequency.In the second part of this thesis, a microfluidic system enabling the production of core-shell microcapsules was developed. First experiments of pancreatic islets encapsulation have shown the ability of this system to minimize the immune reaction towards these capsules.This work is a first step towards encapsulation system optimization, which eventually, may provide capsules that meet all the capsule requirements for transplantation
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Brousse, Benoit. "Réalisation et caractérisation de cellules photovoltaïques organiques obtenues par dépôt physique." Limoges, 2004. http://aurore.unilim.fr/theses/nxfile/default/18ec08d7-8895-42e8-841f-8700f4977e59/blobholder:0/2004LIMO0042.pdf.
Abstract:
Ce travail concerne l'élaboration et la caractérisation de cellules photovoltaïques organiques (OPVs) bas coût, contribuant au développement des énergies renouvelables, et capables d'alimenter des appareils nomades (téléphone portable. . . ). Nous avons en particulier contribué au développement d'un banc d'expérimentation versatile destiné à l'obtention de diverses structures (bicouches, interpénétrées et multicouches) de cellules solaires à base de différents couples donneur-accepteur de petites molécules. Après la présentation d'une rétrospective des phénomènes physique et des mécanismes entrant en jeu, ainsi que celle du principe photovoltaïque dans les matériaux organiques, nous décrivons l'élaboration de notre manipulation et les étapes technologiques permettant de réaliser les cellules solaires. Les matériaux (organiques et métalliques) sont déposés en films minces (de 30 à 100nm) à la tournette (PEDOT-PSS) ou par évaporation sous vide (petites molécules et métallisation de la cathode) sur un substrat de verre recouvert d'une couche conductrice et semi-transparente d'ITO constituant l'anode. Les structures réalisées ont été caractérisées à l'air dans l'obscurité et sous illumination par des courbes I(V), des mesures capacitives et des spectres d'IPCE (spectre de photocourant). Différents couples donneur-accepteur (phtalocyanine/C60, oligomère de thiophène/C60 et phtalocyanine/dérivé de pérylène) ont été testés selon diverses configurations : hétérojonctions p-n distribuées ou non dans le volume. Les performances relevées laissent un avantage aux structures bicouches en raison de la granulosité du C60. Cette caractéristique nous a permis de concevoir une structure multicouche (CuPc/C60)3 efficace. Afin de remédier au problème lié au dépôt du C60, nous avons testé une autre molécule de type accepteur : un dérivé du pérylène (PPTC). Des études complémentaires ont été menées par l'implantation ionique des couches actives, permettant à la fois une densification et un dopage de celles-ci ; l'encapsulation des composants par VDP de polyimide (polymérisation en phase gazeuse) a été évaluée. A l'aide de cette technique, nous avons aussi développé une structure auto-protégée alternative
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Capone, Stéphanie. "Encapsulation d'hépatocytes dans un biomatériau poreux en vue d'une implantation dans un modèle animal." Compiègne, 2012. http://www.theses.fr/2012COMP2033.
Abstract:
Pour pallier le manque de solutions thérapeutiques et le faible nombre de greffons hépatiques disponibles pour traiter certaines atteintes du foie, l’ingénierie tissulaire et l’implantation de tissus reconstruits représentent des solutions potentielles à explorer. Notre approche repose sur la microencapsulation de cellules hépatiques humaines dans des billes d’alginate poreuses. Dans un premier temps, ce travail de thèse a permis de mettre en place de nouvelles combinaisons de matériaux a partir de l’alginate et d’analyser l’influence de ces matériaux sur le comportement mécanique des billes et sur le comportement cellulaire de la lignée HepG2 C3A. La conclusion de cette étude montre que l’ajout de collagène et/ou de coating de poly-L-lysine augmente la rigidité des billes et diminue les coefficients de transfert à l’intérieur de la bille, tout en permettant une prolifération et un maintien de la fonctionnalité des cellules HepG2 C3A. Ensuite, à titre préliminaire, les billes ont été implantées chez un modèle de souris immunocompétente afin d’évaluer la biocompatibilité des matériaux. Dans un deuxième temps, les hépatocytes humains primaires ont été encapsulés dans des billes d’alginate mélangées ou non avec du collagène de type I et mis en culture sur des durées de 7 a 14 jours. Les résultats montrent une perte du niveau basal des expressions et des activités des cytochromes P450 3A4 et 1A1, de la fonctionnalité et de la différenciation des hépatocytes en culture statique. Dans un dernier temps, les hépatocytes humains primaires encapsules ont été mis en culture dans deux types de bioréacteurs afin d’étudier l’effet de la culture en condition dynamique. Les résultats montrent que la culture dynamique en lit fluidise permet d’augmenter la fonctionnalité et la différenciation des hépatocytes encapsules. Cette méthode de culture pourrait donc être employée avant l’implantation des hépatocytes microencapsulés, afin d’assurer une viabilité optimale et un maintien des fonctions métaboliques indispensables dans un contexte de suppléance hépatiqueFurther to the lack of therapeutic solutions and the low number of hepatic transplants available to treat some hepatic diseases, tissue engineering and implantation of reconstructed tissue are possible alternatives to explore. Our approach is based on microencapsulation of hepatic cells in porous alginate beads. In a first time, this thesis work allowed to set up new combinations of materials based on alginate and to analyze their influence on bead mechanical behavior and on HepG2 C3A behavior. The results of this study shown that the adding of collagen and/or of poly-L-lysine coating increased the rigidity of the beads and decreased the mass transfer coefficients inside the bead while allowing a proliferation and a preservation of the functionality of HepG2 C3A. Then, the beads were implanted in small animal model of immunocompetent mice to estimate the biocompatibility of the different materials. In a second time, the primary human hepatocytes were encapsulated in beads of alginate mixed or not with type I collagen and cultivated during 7 to 14 days. The results have shown a basal loss of the level of the expressions and the activities of cytochromes P450 3A4 and 1A1, the functionality and the differentiation of encapsulated primary human hepatocytes. In a last time, encapsulated primary human hepatocytes were cultivated in two types of bioreactors in order to analyze the effect of dynamic culture conditions. The datas shown that the dynamic culture in fluidized bed bioreactor enhanced the functionality and the differentiation of encapsulated hepatocytes. This culture condition could be used before implantation of encapsulated hepatocytes in order to assure an optimal viability and a good maintenance of metabolic functions essential in a context of hepatic suppliance
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Hached, Fahd. "Encapsulation de cellules stromales mésenchymateuses humaines dans les hydrogels polysaccharidiques : potentielle application dans le traitement de l'arthrose." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT1038/document.
Abstract:
Les traitements actuels de l’arthrose ne sont pas étiologiques. Il est alors nécessaire de développer de nouveaux axes thérapeutiques. L’utilisation des cellules stromales mésenchymateuses (CSM) est prometteuse notamment en raison de leurs capacités immunomodulatrices. L’injection intra-articulaire des CSM présente quelques limites majeures qui pourraient être contournées par leur incorporation dans des biomatériaux. Cependant, le maintien des capacités immunomodulatrices des CSM après encapsulation n’a jamais été vérifié. Dans ce contexte, ce travail de thèse a consisté à encapsuler les CSM dans l’alginate et l’hydroxypropyl methylcellulose silanisée (HPMC-Si) puis à étudier leur biofonctionnalité. Dans un premier temps, une méthode de génération de particules d’HPMC-Si a été mise au point. Les particules d’alginate et d’HPMC-Si ont été caractérisées. La taille, les propriétés de diffusion et les propriétés mécaniques des particules fabriquées ont été analysées et comparées. Dans un second temps, les cellules ont été encapsulées dans les 2 matériaux puis caractérisées par une étude de leur viabilité et de leur prolifération pendant 1 mois. Enfin, le maintien des capacités immunomodulatrices des CSM après encapsulation a été investigué. Ces travaux de thèse ont permis de démontrer que : (i) les particules d’alginate et d’HPMC-Si possèdent des propriétés différentes ; (ii) les CSM encapsulées dans les 2 matériaux restent viables et (iii) l’encapsulation des CSM n’altère pas leurs capacités immunomodulatrices. Ces travaux de thèse sont ainsi encourageants pour une potentielle application des CSM encapsulées dans le traitement de l’arthroseExisting drug therapies for osteoarthritis (OA) provide, at best, symptomatic relief from pain and fail to prevent cartilage damage. Mesenchymal Stromal Cells (MSC) have generated interest since they secrete immunomodulatory factors. Direct injection of MSCs in OA suffers major limitations. To overcome these limitations, several studies have proposed to entrap MSC within biomaterials. However, their immunomodulatory properties after encapsulation have not been investigated. In this context, this work aimed to entrap MSC within spherical particles derived from alginate or from silanized hydroxypropyl methylcellulose (Si-HPMC) and to investigate their biofunctionality. First, a protocol of Si-HPMC particles generation was assessed. Alginate and Si-HPMC particles were characterized. Size, diffusion and mechanical properties of generated particles were studied and compared. Secondly, MSC were entrapped within alginate or Si- HPMC. Their viability and their ability to proliferate were evaluated for up to one month after encapsulation. Lastly, the biofunctionality of encapsulated MSC was investigated in order to harness their therapeutic properties for the treatment of OA. In summary, we have shown that: (i) alginate and Si-HPMC particles exhibit different properties; (ii) both alginate and Si-HPMC particles support MSC survival and (iii) MSC encapsulated in alginate or Si-HPMC are sensitive to pro-inflammatory cytokines and respond to this stimulation by increasing their secretion of bioactive factors. These findings are promising for a potential application of encapsulated MSC to OA treatment
Books on the topic "Encapsulation de cellules":
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M, Kühtreiber Willem, Lanza R. P. 1956-, and Chick William L. 1938-, eds. Cell encapsulation technology and therapeutics. Boston: Birkhauser, 1999.
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Goosen, Mattheus F. A. Fundamentals of animal cell encapsulation and immobilization. Boca Raton, Fla: CRC Press, 1993.
Book chapters on the topic "Encapsulation de cellules":
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Bedford, Michael R. "Xylanases, β-glucanases and cellulases: their relevance in poultry nutrition." In Enzymes in farm animal nutrition, 52–69. 3rd ed. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781789241563.0004.
Abstract:
Abstract This chapter discusses the history of enzyme use in poultry feeds, non-starch polysaccharide-degrading enzymes (NSPases), mode of action of NSPases, nutrient encapsulation, viscosity, prebiotic effects of oligosaccharides, fibre digestion and future enzyme development.
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Fraker, C., and C. L. Stabler. "Optimization of Perfluorocarbon Emulsions for Cellular Encapsulation." In IFMBE Proceedings, 165–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-01697-4_60.
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Chua, Sock Teng, Xia Song, and Jun Li. "Hydrogels for Stem Cell Encapsulation: Toward Cellular Therapy for Diabetes." In Springer Series in Biomaterials Science and Engineering, 113–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-57511-6_5.
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Engelmann, F., E. E. Benson, N. Chabrillange, M. T. Gonzalez Arnao, S. Mari, N. Michaux-Ferriere, F. Paulet, J. C. Glaszmann, and A. Charrier. "Cryopreservation of Several Tropical Plant Species using Encapsulation/Dehydration of Apices." In Current Issues in Plant Molecular and Cellular Biology, 315–20. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0307-7_43.
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Oseni, Adelola O., Peter E. Butler, and Alexander M. Seifalian. "Rapid Production of Autologous Fibrin Hydrogels for Cellular Encapsulation in Organ Regeneration." In Methods in Molecular Biology, 145–52. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-363-3_12.
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"Cellulose Ethers: Applications." In Handbook of Encapsulation and Controlled Release, 541–58. CRC Press, 2015. http://dx.doi.org/10.1201/b19038-35.
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Yang, Yong. "Ethylcellulose." In Polymer Data Handbook, 146–51. Oxford University PressNew York, NY, 2009. http://dx.doi.org/10.1093/oso/9780195181012.003.0024.
Abstract:
Abstract Major Applications Lacquers for wood, plastic, and paper, varnishes, hot melts, adhesives, thickener for coatings and inks, tablet coatings and binding, encapsulation. Preparative Techniques Ethylcellulose is prepared by reacting ethyl chloride with alkali cellulose, as expressed by the following reaction:
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"Cellulose- Based Biopolymers: Formulation and Delivery Applications." In Handbook of Encapsulation and Controlled Release, 559–98. CRC Press, 2015. http://dx.doi.org/10.1201/b19038-36.
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Babovic, V., and A. W. Minns. "Hydroinformatics opening new horizons: union of computational hydraulics and artificial intelligence." In Michael Abbott's Hydroinformatics, 33–44. IWA Publishing, 2022. http://dx.doi.org/10.2166/9781789062656_0033.
Abstract:
Abstract The strengthening dominance of electronics over past several decades has resulted in an almost total dominance of digital representation of the hydro-environment. Recognizing these developments, Mike Abbott introduced the notion of electronic encapsulation of information and knowledge. The act of encapsulating information and knowledge changes the very nature of the information and knowledge involved. Suffice to say that electronic encapsulation must also change the way in which an engineer accesses and uses the available information and knowledge. There is a shift in paradigm away from a model-based approach to a more data-based approach. Adopting such foundational considerations as its core, hydroinformatics opened research to the latest IT developments in the fields of artificial intelligence (including machine learning, evolutionary algorithms and artificial neural networks), artificial life, cellular or finite-state automata and other, previously unrelated sciences and technologies. Through studying and exploiting elements of these, at first sight unrelated, sciences, hydroinformatics produced new and innovative solutions to hydraulic and hydrological problems, as represented by real-time control and diagnosis, real-time forecasting, calibration of numerical models, data analysis and parameter estimation. In particular, the new approaches are able to generate important components of physically based, modelling systems by inducing models or sub-models of individual physical processes based only upon measured data. These (sub)models may then replace whole systems of complex, non-linear, differential equations that would otherwise require great skills from the modeller to calibrate, and powerful computing devices to solve. This chapter captures evolution of data science and AI within the field of hydroinformatics and provides an outline of the present state-of-affairs together with some ideas for future directions. The chapter outlines tangible solutions that have been applied by the hydroinformatics community to address specific challenges in hydro-environmental systems.
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Fathi, Milad, Mehri Karim, and Nadia Ahmadi. "Nanostructures of cellulose for encapsulation of food ingredients." In Biopolymer Nanostructures for Food Encapsulation Purposes, 493–519. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-12-815663-6.00017-3.
Conference papers on the topic "Encapsulation de cellules":
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Reátegui, Eduardo, Lisa Kasinkas, and Alptekin Aksan. "Encapsulation of Mammalian Cells in Nanoporous Silica Gels: Interactions at the Biointerface." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80211.
Abstract:
Encapsulation of cells in nanoporous silica gels has shown great potential for the development of biotechnology applications such as biosensors, biocatalysis, bioremediation, energy conversion systems, and cellular therapies [1]. However, even though the inorganic matrix confers improved mechanical properties, chemical and thermal stability, and is resistant to microbial attacks, long-term viability and function after encapsulation remains as one of the principal setbacks of this technology [2].
2
Wellala, Harini Chamathka, Ravichandran Vinushayini, Lasantha Herath, and Colin N. Peiris. "Increasing Efficiency of Liquid Fertilizer via Incorporating Beneficial Microorganisms." In SLIIT International Conference on Advancements in Sciences and Humanities 2023. Faculty of Humanities and Sciences, SLIIT, 2023. http://dx.doi.org/10.54389/htea3029.
Abstract:
The growing trend in organic agriculture has boosted the public awareness of organic fertilizer. The present study focused on isolating plant growth promoting microorganisms from the soil samples and incorporating beneficial plant growth promoting microbial (PGPM) strains to a provided liquid organic fertilizer to improve the efficiency of current formula. After isolating plant growth promoting microorganisms, experiments were conducted qualitatively and quantitatively to evaluate the efficacy of those species. Five phosphorous solubilizing bacteria and fungi, one potassium solubilizing bacteria, one potassium solubilizing fungi, six free living nitrogen fixing bacteria from different regions including Hambanthota, Mahiyanganaya, Galaha, Welimada, Rathnapura Sri Lanka were isolated using serial dilution plating on specific growth media and screened for various plant growth-promoting traits. The highest phosphate solubilization (67.8 mg/ml) was exhibited in PH.1 which also exhibited the highest phosphorous solubilization index (PSI) of 2, isolated from the soil sample received from Hambanthota district. Alginate encapsulation as small beads were produced from bacterial inoculum of PH.1 phosphorous solubilizing bacteria with sodium alginate, cellulose, and calcium chloride. A series of different percentages of cellulose (3% - 6%) was used during bead formation to evaluate the effect of cellulose on encapsulation efficiency of beads. Alginate beads were applied to the liquid fertilizer, incubated, and plated periodically to evaluate the efficiency of this formulation. The number of released cells of PH.1 reached 7.36 X 10 6 CFU/ml after 48 hours of incubation in the 0.25 X diluted liquid fertilizer which resulted from the bead formulation of 4% (w/v) Alginate + 3% (w/v) cellulose. The cellulose supported the entrapment of bacterial cells (plant growth-promoting bacterium) PH.1 as biofertilizer in the matrix, which reduced cell loss. The highest entrapment efficiency of 5.441% was obtained at 3% (w/v) cellulose, Overall, the appropriate content of cellulose mixed with alginate is conducive to changes in the morphology of microcapsules and increases the amount of biological encapsulation. This indicates that the beads-based biofertilizer can partially replace chemical fertilizers.
3
Li, Lulu, Rene Schloss, Noshir Langrana, and Martin Yarmush. "Effects of Encapsulation Microenvironment on Embryonic Stem Cell Differentiation." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192587.
Abstract:
Pluripotent embryonic stem cells represent a promising renewable cell source to generate a variety of differentiated cell types. Although many investigators have described techniques to effectively differentiate stem cells into different mature cell lineages, their practicality is limited by the absence of large scale processing consideration and low yields of differentiated cells. Previously we have established a murine embryonic stem cell alginate-poly-l-lysine microencapsulation differentiation system. The three-dimensional alginate microenvironment maintains cell viability, is conducive to ES cell differentiation to hepatocyte lineage cells, and maintains differentiated cellular function. In the present work, we demonstrate that hepatocyte differentiation is mediated by cell-cell aggregation in the encapsulation microenvironment. Both cell aggregation and hepatocyte functions, such as urea and albumin secretion, as well as increased expression of cytokaratin 18 and cyp4507a, occur concomitantly with surface E-cadherin expression. Furthermore, by incorporating soluble inducers, such as retinoic acid, into the permeable microcapsule system, we demonstrate decreased cell aggregation and enhanced neuronal lineage differentiation with the expression of various neuronal specific markers, including neurofilament, A2B5, O1 and GFAP. Therefore, as a result of capsule parameter and microenvironment manipulation, we are capable of targeting cellular differentiation to both endodermal and ectodermal cell lineages.
4
Seymour, John P., and Daryl R. Kipke. "Fabrication of Polymer Neural Probes with Sub-cellular Features for Reduced Tissue Encapsulation." In Conference Proceedings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2006. http://dx.doi.org/10.1109/iembs.2006.260528.
5
Seymour, John P., and Daryl R. Kipke. "Fabrication of Polymer Neural Probes with Sub-cellular Features for Reduced Tissue Encapsulation." In Conference Proceedings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2006. http://dx.doi.org/10.1109/iembs.2006.4398478.
6
Putranto, Muhammad Adi, Emil Budianto, and Sumi Hudoyon. "Encapsulation and dissolution study of bromelain in chitosan-methyl cellulose semi-IPN hydrogel." In THE 3RD INTERNATIONAL SEMINAR ON CHEMISTRY: Green Chemistry and its Role for Sustainability. Author(s), 2018. http://dx.doi.org/10.1063/1.5082438.
7
Li, Lulu, Alexander Davidovich, Jennifer Schloss, Uday Chippada, Rene Schloss, Noshir Langrana, and Martin Yarmush. "Control of Neural Lineage Differentiation in an Alginate Encapsulation Microenvironment via Cellular Aggregation." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206496.
Abstract:
Cell replacement therapies, which utilize renewable stem cell sources, hold tremendous potential to treat a wide range of degenerative diseases. Although many studies have established techniques to successfully differentiate stem cells into different mature cell lineages, their practicality is limited by the lack of control during the differentiation process and low yields of differentiated cells. In order to address these issues, we have previously established a murine embryonic stem cell alginate-poly-L-lysine microencapsulation differentiation system [1]. We demonstrated that ES cell differentiation could be mediated by cell-cell aggregation in the encapsulation microenvironment. We have demonstrated that both cell aggregation and hepatocyte functions, such as urea and albumin secretions, as well as increased expression of cytokeratin 18 and cyp4507a, occur concomitantly with surface E-cadherin expression [2]. In the present studies, we assessed the feasibility of inducing neuronal lineage differentiation in the alginate microenvironment by incorporating soluble inducers, such as retinoic acid, into the permeable microcapsule system. We demonstrated decreased cell aggregation and enhanced neuronal lineage differentiation with the expression of various neuronal specific markers, including neurofilament, A2B5, O1 and glial fibrillary acidic protein (GFAP). In addition, we demonstrated that, by blocking the cell aggregation using anti-E-cadherin antibody, encapsulated cells increased neuronal marker expression at a later stage of the encapsulation, even in the absence of retinoic acid. In conjunction with the mechanical and physical characterizations of the alginate crosslinking network, we show that 2.2% alginate concentration is most conducive to neuronal differentiation from embryonic stem cells in the presence of retinoic acid.
8
Chukwurah, Kengelle Q., Yaping Yang, Jian Wang, Yajun Yan, and Eric C. Freeman. "Incorporating Stimuli-Responsive Bacteria in Microfluidic Droplets." In ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-9041.
Abstract:
Model cellular membranes respond to chemical and electrical stimuli, regulating transport and exchange between two neighboring aqueous droplets. This regulated exchange may prove useful for controlling aqueous micro-environments for studying stimuli-responsive encapsulated bacteria. This concept is explored in this work, focusing on characterizing the bacterial response within a synthetic cellular environment. In the droplet interface bilayer (DIB) approach, aqueous micro-droplets deposited in an oil reservoir with dissolved lipids are coated with lipid monolayers and arranged into artificial cellular networks. This approach has been explored for potential use as a biologically-inspired smart material, but new material transduction pathways are necessary. This may be accomplished by combining this bottom-up approach to synthetic biology with living organisms such as stimuli-responsive bacteria. Bacteria encapsulation within the microfluidic droplets begins with a strain of Escherichia coli (E. coli), XL1-Blue. These flagellated bacteria naturally respond and move towards chemoattractants such as casamino acids, and their motion may be tracked through differential interference contrast (DIC) and fluorescent microscopy. Chemotaxis of XL1-Blue was assessed through low-flow perfusion of the chemoattractant (casamino acids) into a buffer solution containing the bacteria through a tailored capillary tube. Next, the response of bacteria within asymmetric DIB networks separating the bacteria and the chemoattractant were studied.
9
Sambanis, Thanassis, Klearchos K. Papas, Robert C. Long, and Ioannis Constantinidis. "Towards the Development of a Bioartificial Pancreas: Long-Term In Vitro Functions of Immunoisolated Mouse Insulinoma Cells." In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-1213.
Abstract:
Abstract A promising method for the long-term treatment of diabetes mellitus consists of the implantation of a functional bioartificial construct containing insulin-secreting cells. Cells are isolated from the immune system of the host by encapsulation in a synthetic semipermeable membrane which allows passage of cellular nutrients and metabolites, including insulin, but excludes antibodies and cytotoxic cells of the host. The effectiveness of such implants in restoring normoglycemia has been repeatedly demonstrated in both small and large diabetic animal models. A limitation to the large-scale application of such implants is cell availability. We are thus investigating the development of stable, functional bioartificial constructs based on transformed insulin-secreting cells that can be amplified in culture thus relaxing the cell availability constrain.
10
Wijayanti, Sri Peni. "Evaluation of an alginate-chitosan-microcrystalline cellulose sulfate encapsulation system for efficient fermentation of lignocellulosic hydrolyzate." In THE 2ND INTERNATIONAL CONFERENCE OF LIGNOCELLULOSE. AIP Publishing, 2024. http://dx.doi.org/10.1063/5.0184474.
Reports on the topic "Encapsulation de cellules":
1
Chejanovsky, Nor, and Bruce A. Webb. Potentiation of Pest Control by Insect Immunosuppression. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7592113.bard.
Abstract:
The restricted host range of many baculoviruses, highly pathogenic to Lepidoptera and non-pathogenic to mammals, limits their use to single or few closely related Lepidopteran species and is an obstacle to extending their implementation for pest control. The insect immune response is a major determinant of the ability of an insect pathogen to efficiently multiply and propagate. We have developed an original model system to study the Lepidopteran antiviral immune response based on Spodoptera littoralis resistance to AcMNPV (Autographa californica multiple nucleopolyhedrovirus) infection and the fascinating immunosuppressive activity of polydnaviruses .Our aim is to elucidate the mechanisms through which the immunosuppressive insect polydnaviruses promote replication of pathogenic baculoviruses in lepidopteran hosts that are mildly or non-permissive to virus- replication. In this study we : 1- Assessed the extent to which and the mechanisms whereby the immunosuppressive Campoletis sonorensis polydnavirus (CsV) or its genes enhanced replication of a well-characterized pathogenic baculovirus AcMNPV, in polydnavirus-immunosuppressedH. zea and S. littoralis insects and S. littoralis cells, hosts that are mildly or non-permissive to AcMNPV. 2- Identified CsV genes involved in the above immunosuppression (e.g. inhibiting cellular encapsulation and disrupting humoral immunity). We showed that: 1. S. littoralis larvae mount an immune response against a baculovirus infection. 2. Immunosuppression of an insect pest improves the ability of a viral pathogen, the baculovirus AcMNPV, to infect the pest. 3. For the first time two PDV-specific genes of the vankyrin and cystein rich-motif families involved in immunosuppression of the host, namely Pvank1 and Hv1.1 respectively, enhanced the efficacy of an insect pathogen toward a semipermissive pest. 4. Pvank1 inhibits apoptosis of Spodopteran cells elucidating one functional aspect of PDVvankyrins. 5. That Pvank-1 and Hv1.1 do not show cooperative effect in S. littoralis when co-expressed during AcMNPV infection. Our results pave the way to developing novel means for pest control, including baculoviruses, that rely upon suppressing host immune systems by strategically weakening insect defenses to improve pathogen (i.e. biocontrol agent) infection and virulence. Also, we expect that the above result will help to develop systems for enhanced insect control that may ultimately help to reduce transmission of insect vectored diseases of humans, animals and plants as well as provide mechanisms for suppression of insect populations that damage crop plants by direct feeding.
2
Chejanovsky, Nor, and Bruce A. Webb. Potentiation of pest control by insect immunosuppression. United States Department of Agriculture, July 2004. http://dx.doi.org/10.32747/2004.7587236.bard.
Abstract:
Our original aims were to elucidate the mechanisms through which the immunosuppressive insect virus, the Campoletis sonorensis polydnavirus (CsV) promotes replication of a well-characterized pathogenic virus, the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in hosts that are mildly or non-permissive to virus replication. According to the BARD panels criticism we modified our short-term goals (see below). Thus, in this feasibility study (one-year funding) we aimed to show that: 1. S. littoralis larvae mount an immune response against a baculovirus infection. 2. Immunosuppression of an insect pest improves the ability of a viral pathogen (a baculovirus) to infect the pest. 3. S. littoralis cells constitute an efficient tool to study some aspects of the anti- viral immune response. We achieved the above objectives by: 1. Finding melanized viral foci upon following the baculoviral infection in S . littoralis larvae infected with a polyhedra - positive AcMNPV recombinant that expressed the GFP gene under the control of the Drosophila heat shock promoter. 2. Studying the effect of AcMNPV-infection in S . littoralis immunosuppressed by parasitation with the Braconidae wasp Chelonus inanitus that bears the CiV polydna virus, that resulted in higher susceptibility of S. littoralis to AcMNPV- infection. 3. Proving that S. littoralis hemocytes resist AcMNPV -infection. 4. Defining SL2 as a granulocyte-like cell line and demonstrating that as littoralis hemocytic cell line undergoes apoptosis upon AcMNPV -infection. 5. Showing that some of the recombinant AcMNPV expressing the immuno-suppressive polydna virus CsV- vankyrin genes inhibit baculoviral-induced lysis of SL2 cells. This information paves the way to elucidate the mechanisms through which the immuno- suppressive polydna insect viruses promote replication of pathogenic baculoviruses in lepidopteran hosts that are mildly or non-permissive to virus- replication by: - Assessing the extent to which and the mechanisms whereby the immunosuppressive viruses, CiV and CsV or their genes enhance AcMNPV replication in polydnavirus- immunosuppressed H. zea and S. littoralis insects and S. littoralis cells. - Identifying CiV and CsV genes involved in the above immunosuppression (e.g. inhibiting cellular encapsulation and disrupting humoral immunity). This study will provide insight to the molecular mechanisms of viral pathogenesis and improve our understanding of insect immunity. This knowledge is of fundamental importance to controlling insect vectored diseases of humans, animals and plants and essential to developing novel means for pest control (including baculoviruses) that strategically weaken insect defenses to improve pathogen (i.e. biocontrol agent) infection and virulence.