Tesis sobre el tema "Interactions cellules/surfaces"
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Lavenus, Sandrine. "Études des interactions entre cellules souches et surfaces implantaires nanostructurées". Nantes, 2010. https://archive.bu.univ-nantes.fr/pollux/show/show?id=2d0946e5-0bbf-466c-a5b0-5c6e5d88f147.
Texto completoMetal implants allow nowadays prosthetic rehabilitations with high clinical success due to their surface properties. Some studies have shown that surface properties such as roughness, wettability and chemistry changed the adhesion and differentiation of cells, and thereby, the integration of implant in tissues. Understanding of the interactions between cells and implant surfaces is essential in the field of tissue engineering and biomaterials. Attachment, adhesion and spreading of cells establish the first step of interaction between cells and surfaces and, so the quality of this step determined the cell capacity to proliferate and differentiate on implant surface. In this context, the aim of this study was to study the adhesion and differentiation of human mesenchymal stem cells (hMSC) on nanostructured surface. In the first part, the adhesion, proliferation and differentiation of hMSC, osteoblasts and gingival fibroblasts were compared on substrates with similar surface roughness and wettability, but different chemistries. Secondly, nanostructured titanium surface were realized and characterized. Titanium vapor deposition was performed on polycarbonate membranes with pores of 50, 200 or 400 nm of diameter. Anodisation also allowed obtaining a regular surface with pores of 30, 50 and 100 nm of diameter. In the last part of this work, the adhesion and osteoblastic differentiation of hMSC were studied on these nanostructured surfaces. Cell adhesion and differentiation have been investigated using staining, immunostaining, image analysis and gene expression. Finally, histomorphometric analysis of anodized implant after 1 and 3 weeks of implantation in rat tibia allowed the characterization of osteointegration. The characterization of surface properties and biological study of different cell type on nanostructured surface was necessary to understand the behaviour of cells and so, the consequence for the osteointegration
Baujard-Lamotte, Lucie. "Interactions surfaces-protéines-cellules : Adsorption de la fibronectine sur supports modèles et influence sur le comportement cellulaire". Cergy-Pontoise, 2007. http://biblioweb.u-cergy.fr/theses/07CERG0390.pdf.
Texto completoIn living tissues, cell behaviors depend on close connections between cells and their environment, the extracellular matrix (ECM). For in vitro cell culture experiments, a classic strategy to improve cell culture is to coat cell culture supports by an ECM protein which is able to promote cell adhesion, like fibronectin. The aim of this thesis is to analyze the surfaces-proteins-cells relationship, and especially the properties of fibronectin adsorbed onto model surfaces and their influence on cell behavior. Different model supports (glass, OTS, polystyrene) are generated and characterized. Then, adsorption kinetics using various protein concentrations are followed, and the amount and the conformational changes of adsorbed fibronectin are concomitantly determined. Finally, cell adhesion and morphology are studied in different cell seeding conditions, and for two cell types
Baujard-Lamotte, Lucie Pauthe Emmanuel. "Interactions surfaces-protéines-cellules Adsorption de la fibronectine sur supports modèles et influence sur le comportement cellulaire /". [s.l.] : [s.n.], 2009. http://biblioweb.u-cergy.fr/theses/07CERG0390.pdf.
Texto completoStalet, Marion. "Protections antimicrobiennes : combinaison de la fonctionnalisation et de la nano-structuration pour explorer les interactions cellule/surface". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. https://theses.hal.science/tel-04651199.
Texto completoMicroorganisms, ubiquitous and resilient, hold the undisputed title of the most persistent inhabitants of our planet. Present on Earth for approximately 4 billion years, their remarkable adaptive mechanisms have enabled them to colonize all environments, even the most extreme, and to play an essential role in them. Although their outstanding proliferation and antibiotic resistance capabilities have been established for at least a century, the end of the golden age of antibiotics in the 1960s has revived concerns. To address the resurgence of this resistance, new technological solutions have been explored to limit contamination in sensitive environments and surfaces, particularly in the medical field. Among these, the fabrication of actively antimicrobial surfaces is particularly relevant. Approaches involving chemical surface functionalization and the release of antimicrobial agents have been extensively explored in recent years but still suffer from disadvantages related to the durability of their activity. Newer approaches, such as the nanofabrication of bioinspired surfaces, also show promise and could complement existing methods. However, the interaction mechanisms between microorganisms and materials are complex, and for each approach, numerous parameters can influence surface effectiveness. Additionally, the lack of standardized protocols to characterize the full antimicrobial properties of surfaces complicates the sharing of knowledge and understanding of mechanisms. This thesis aims to highlight the impact of specific surface design parameters and the importance of taking them into account to design effective solutions, utilizing chemical functionalization with antimicrobial peptides and nanostructuring through electrodeposition. Drawing on the study of Escherichia coli and Staphylococcus epidermidis, two bacterial strains relevant for their impact on human health and their morphological differences, a comprehensive protocol for microbiological characterization of antimicrobial properties, accompanied by semi-automatic algorithms allowing faster data processing, has been developed. This protocol has been applied to assess the effectiveness of the approaches, whether individually or in combination. The obtained results contribute to a better understanding of the impact of the various studied parameters and emphasize key steps in comprehending and evaluating antimicrobial properties
Balu, Balamurali. "Plasma processing of cellulose surfaces and their interactions with fluids". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31675.
Texto completoCommittee Chair: Breedveld, Victor; Committee Chair: Hess, Dennis; Committee Member: Aidun, Cyrus; Committee Member: Deng, Yulin; Committee Member: Singh, Preet. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Lord, Megan Susan Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Biomolecular and cellular interactions with surfaces". Awarded by:University of New South Wales. Graduate School of Biomedical Engineering, 2006. http://handle.unsw.edu.au/1959.4/24213.
Texto completoStiernstedt, Johanna. "Interactions of cellulose and model surfaces". Doctoral thesis, Stockholm : Chemical Science and Engineering, KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-619.
Texto completoFrazier, Richard Andrew. "Macromolecular interactions at polysaccharide surfaces". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336946.
Texto completoPoptoshev, Evgeni. "Polyelectrolyte Moderated Interactions between Glass and Cellulose Surfaces". Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3247.
Texto completoTze, William tai-Yin. "Effects of Fiberimatiux Interactions on the Interfacial Deformation Micromechanics of Cellulose-Fiberipolymer Composites". Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/TzeWT2003.pdf.
Texto completoSharma, Sumana. "Genome-scale identification of cellular pathways required for cell surface recognition". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271825.
Texto completoÖsterberg, Monika. "On the interactions in cellulose systems : surface forces and adsorption". Doctoral thesis, KTH, Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3017.
Texto completoIn this thesis the interactions in cellulose systems havebeen studied with emphasis on surface forces and adsorptionphenomenon. The study was limited to surfaces and polymers ofinterest for papermaking. During papermaking both therunability of the paper machine as well as the properties ofthe final paper will depend on the molecular interactionsbetween the components present in the suspension. The objectiveof this work was to gain a better understanding of theseinteraction forces and how they are affected by solutionconditions like pH and electrolyte concentration. The maintechniques employed for this purpose were direct surface forcemeasurements using both the interferometric surface forceapparatus (SFA) and the atomic force microscopy (AFM)colloidal-probe technique. In addition, both electronspectroscopy for chemical analysis (ESCA) and AFM imaging wereused for surface characterisation and to study adsorptionbehaviour. Since a smooth and transparent surface is needed forsurface force studies using SFA, Langmuir-Blodgett films ofcellulose were employed.
The interactions between cellulose surfacesand xylansurfaces were studied. Cellulose is the main constituent of thewood fibre. In close association with cellulose in the cellwall are the hemicelluloses, xylan being a commonhemicellulose. Steric forces were found to dominate theinteractions between these substances in aqueous solutions.Still factors like charge density, solution pH and electrolyteconcentration were important. The adhesion between cellulosesurfaces in air depended on the contact area. The effect of acationic polyelectrolyte on the forces between cellulosesurfaces and between cellulose and mineral surfaces wasinvestigated to obtain a better understanding of the effects ofcationic retention and strength additives. In the presence of acationic polyelectrolyte the forces at large distances weredominated by double-layer repulsion. Bridging attraction was insome cases observed, but the presence and magnitude of thisforce was dependent on the properties of the substratesurface.
Lignin on the fibre surface affects brightness, swelling andstrength of paper. In addition, dissolved lignin interfereswith added polymers during papermaking. For this reason theadsorption of lignin on cellulose fibre surfaces was explored.The adsorption of lignin was influenced by the concentration oflignin in solution and by the electrolyte composition of thesolution. The retention of lignin was affected by the presenceof a cationic polyelectrolyte and particularly by how thepolyelectrolyte was added. The AFM imaging revealed thestructure of the adsorbed lignin, which varied with the way ofadding the polyelectrolyte, and gave an idea about theadsorption mechanism. The effect of lignin on strengthproperties of paper sheets was also evaluated.
Keywords: cellulose, hemicellulose, xylan, lignin, surfaceforces, adsorption, polyelectrolyte, SFA, AFM, ESCA,Langmuir-Blodgett films, chitosan, steric forces,bridging,adhesion
Lashkor, Minhaj. "Switchable surfaces for regulating biomolecular and cellular interactions under complex biological conditions". Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5902/.
Texto completoSergeeva, Yulia. "Complexes ADN/polycation en solution et aux interfaces en tant que vecteurs de transfection non viraux de pointe". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01064224.
Texto completoHeintz, Eva Liang-Huang. "Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4944.
Texto completoUtsel, Simon. "Surface Modification of Cellulose-based Materials for Tailoring of Interfacial Interactions". Doctoral thesis, KTH, Fiberteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102368.
Texto completoQC 20120918
Chauve, Grégory. "Interactions de surface avec la cellulose en milieu dense et dilué". Université Joseph Fourier (Grenoble), 2003. http://www.theses.fr/2003GRE10188.
Texto completoColetti, Camilla. "Silicon Carbide Biocompatibility, Surface Control and Electronic Cellular Interaction for Biosensing Applications". [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002285.
Texto completoFoo, Guo Shiou. "Surface interactions of biomass derived oxygenates with heterogeneous catalysts". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54455.
Texto completoThakar, Dhruv. "Surfaces biomimétiques pour caractériser les interactions induites par les glycosaminoglycanes aux niveaux moléculaire, supramoléculaire et cellulaire". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV005/document.
Texto completoThe oriented migration and controlled adhesion of cells is fundamental to many physiological and pathological processes. A family of linear polysaccharides, known as glycosaminoglycans (GAGs), help organizing and presenting signaling proteins, so-called chemokines, on the cell surface and in the extracellular matrix thus regulating cellular behavior. The objective of this PhD thesis was to develop biomimetic surfaces that are highly defined and tunable, for mechanistic studies of GAG-protein interactions on the molecular and supramolecular levels, and to probe cellular responses to defined biochemical and biophysical cues to better understand GAG-mediated cell-cell and cell-matrix communications.Applying oxime ligation, GAGs could be stably functionalized with biotin at the reducing end, and these features proved crucial for the reliable preparation of GAG-functionalized surfaces. A streptavidin monolayer served as a ‘molecular breadboard' to sequentially assemble biotinylated molecules with controlled orientation and surface densities. GAGs (heparan sulfate (HS) in particular), chemokines and other ECM components (e.g. integrin ligands promoting cell adhesion, RGD) were assembled into multifunctional surfaces that recapitulate selected aspects of the in vivo situation. Quartz crystal microbalance (QCM-D) and spectroscopic ellipsometry permitted us to characterize and control the supramolecular presentation of HS and RGD. These model surfaces were used to study the supramolecular interactions between HS and the selected chemokine stromal derived factor SDF-1α/CXCL12α and to analyze cellular responses to extracellular cues. Our data provide evidence that CXCL12α binding rigidifies HS assemblies, and that this effect is due to protein-mediated cross-linking of HS chains. The kinetics of chemokine binding to HS was quantified using surface plasmon resonance (SPR). We also demonstrate that the way in which the chemokine is presented, and in particular the presence of HS, is important for regulating myoblast behavior. Our data shows that the cell surface receptors CXCR4 (the CXCL12α receptor) and integrins (the RGD receptor) can act synergistically in controlling cellular adhesion and migration. These surfaces can generate novel insights in the field of glycobiology, e.g. in dissecting the function of GAGs in chemokine-mediated cellular migration
Forni, Luciana. "Recepteurs membrananires des lymphocytes b : interactions entre recepteurs et physiologie des cellules b". Paris 6, 1987. http://www.theses.fr/1987PA066375.
Texto completoTrent, Alexis Raven. "Fabrication, Characterization and Cellular Interactions of Keratin Nanomaterial Coatings for Implantable Percutaneous Prosthetics". Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/94417.
Texto completoPh. D.
Kirichuk, Oksana. "Avancées dans les études in vitro des interactions cellule-glycocalyx : développement d'une plateforme définie mécaniquement et biochimiquement". Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALY084.
Texto completoCell adhesion to the blood vessel wall is a complex, highly regulated physiological process. Red blood cells must repel from the blood vessel wall to prevent blood clotting while immune cells can be recruited from the vascular system to migrate into surrounding tissues. Cell adhesion hinges on the critical role played by the glycocalyx, a soft gel-like layer coating the vascular wall. However, how glycocalyx mechanical (softness, thickness) and biochemical (the composition and the density of surface receptors) properties affect this regulation is still poorly understood. Our hypothesis is that selective cell adhesion requires an intricate interplay of mechanical and biochemical cues. Elucidating the physical and molecular mechanisms that underpin selective adhesion directly in real blood vessels is challenging owing to the complexity and lack of control in in vivo systems. In my research, I aimed to construct an in vitro molecular interaction platform to facilitate mechanistic analyses. The platform combines a molecularly-defined model of the glycocalyx with mimetics of white blood cells under flow. While developing such a platform posed challenges, it offers the advantage of precise control over the physical and biochemical parameters of both the glycocalyx mimetic and cell mimetics.The newly developed glycocalyx model includes several key ingredients with tightly controlled properties: a brush of hyaluronan (HA, an essential component of the endothelial glycocalyx) is combined with P-selectin (an adhesion molecule on the endothelial cell surface critical for the homing of leukocytes). Building on previous experience in my research group, I employed a silica-supported lipid bilayer (SLB) bearing a monolayer of streptavidin (SAv), that can bind biotinylated molecules via biotin-SAv bonds. I introduce here a control of the in-plane mobility of molecules anchored to the fluid lipid bilayer using glutaraldehyde (GTA) as a cross-linking agent for SAv. Controlled grafting densities of one-end biotinylated HA chains of various lengths then create brushes of different mechanical properties. I also present a new methodology for quantitatively tuning the grafting density of smaller biotinylated molecules, which is deployed here to control the grafting density of an ‘adapter protein’ for anchoring P-selectin. The new in vitro model of the glycocalyx thus affords control over the lateral mobility, the surface density and the orientation of two distinct functional molecules.The second key component of the newly developed platform consists of white blood cell mimetics, developed based on commercially available microbeads with the size of a cell and a SAv coating. I introduce a methodology for simultaneous grafting of two types of proteins onto the bead surface: biotinylated CD44 (a ligand expressed on leukocyte surfaces, interacting specifically with HA) and PSGL-1 (a ligand of P-selectin). Additionally, I present a method for controlling the surface density of each of these proteins.I use a combination of methods as monitoring and quality control tools of glycocalyx model formation and bead functionalization: quartz crystal microbalance with dissipation monitoring (QCM-D); spectroscopic ellipsometry (SE), reflection interference contrast microscopy (RICM); confocal microscopy with fluorescence recovery after photobleaching (FRAP) capabilities, and flow cytometry.This newly established platform provides a controlled environment for studying blood cell adhesion, effectively bridging the divide between cell-glycocalyx chemical interactions and the mechanical aspects of cell migration under flow, including attachment and repulsion from the vascular wall. This platform holds the potential for expansion to encompass other surface adhesion molecules or to integrate multiple adhesion molecules, to gradually advance from the bottom up our understanding of the mechanisms governing cell adhesion to blood vessels
Lipsker, Dan Michael. "Interactions de la protéine de stress hsp70 avec les cellules dendritiques humaines : Etude du trafic de certains antigènes de surface des cellules de Langerhans humaines". Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13044.
Texto completoKittle, Joshua Daniel. "Characterization of Cellulose and Chitin Thin Films and Their Interactions with Bio-based Polymers". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26806.
Texto completoPh. D.
Jiang, Jian-Qiao. "Conception, préparation et évaluation des performances de dispositifs de capture de microvésicules à base de complexes polymétalliques : effet de la dendricité". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0376.
Texto completoMicrovesicles (MVs) have been a growing research interest at the front line of disease diagnosis. They are used by almost all types of cells in the human body as a tool of intercellular communication, thus can be sampled from most of the extracellular fluids without causing severe damage to the surrounding tissue. They are formed by budding of cell membrane, thus their membrane proteins are reminiscent to that of their parent cells, allowing them to be traced back to their parent cell types. They contain rich varieties of biomolecules including lipid, protein, and nucleic acids, thus the analysis of them will provide valuable physiological and pathological information on their cells of origin. They are released under cellular stress, thus they represent the early cellular response to corresponding stimuli. In other words, an analysis of them is able to provide an approach for the early detection of pathological conditions. A full characterization of the MVs includes their population per unit volume of the sample liquid, their size distribution, their morphology, their composition of lipid, protein, and nucleic acids. Unfortunately, there isn’t a platform developed allowing all the aforementioned tests at the same time, while existing test protocols are severely limited by the pre-analytical treatments, especially the purification processes. Herein, we present the design and construction of a device on which microvesicles can be captured, accommodating both physical and chemical analysis on the MVs within an extracellular fluid sample.For the device construction, we first synthesized a series of dendrons with increasing dendricity that are able to specifically bind to phosphatidylserine (PS), a lipid molecule exposing only on the outer leaflet of extracellular vesicles. The dendron peripherals are functionalized with dipicolylamine-Zn2+ (DPA-Zn) complexes to provide the dendron-phosphatidylserine interaction. The convergently synthesized dendrons are adopted as the molecular support for the complex units so that the binding ability of dendrons to PS can be controlled and improved through multivalency and synergy of neighboring DPA-Zn units. The core of each dendron is attached to an n-hexylamine spacer, allowing the attachment to the material surface
Castellana, Donatello. "Tumor-derived microvesicles in cancer progression : In vitro study in a prostate cancer model". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13034.
Texto completoThe plasma membrane plays a pivotal role in a large number of physiological processes. After cellular stimulation, externalization of PS in the exoplasmic leaflet of plasma membrane is followed by the shedding of membrane microvesicles (MV) in almost all cell types. MV composition reflect the antigenic profile of cells which they originate from, depending on the stimulus apply. Tumour microenvironment is highly enriched in MV shed from cells infiltrating the tumour tissue. Fibroblasts are associated with tumour cells at all stages of cancer progression. Focusing on fibroblasts implication in cancer, we propose an in vitro model in which cancer and normal cells communicate each other via MV. The aim of this study is to elucidate a mechanism, in which prostate cancer cells influence the behaviour of normal stromal cells that in turn affect the aggressiveness of carcinoma cells by mutual MV shedding, promoting or support the creation of a niche favourable for tumour development
Bernier, Marie-Charlotte. "Étude des interactions de nanoparticules de dioxyde de titane manufacturées avec des cellules et des biomolécules". Compiègne, 2011. http://www.theses.fr/2011COMP1973.
Texto completoThe small size (<100 nm) of titanium dioxide nanoparticles (nTiO2) gives them special properties that make them usefull for many everyday life applications (cosmetics, biomaterials. . . ). However, their effects on human health and the environment remain unkown or misunderstood. In this study, anatase nTiO2 and silica-coated rutile nTiO2 were tested on two murine cell lines: MC-3T3 pre-osteoblasts and L929 fibroblasts. In order to understand the cytotoxic mechanisms, TiO2 nanoparticles aggregation in different culture media and their interaction with fibronectin (Fn) –the major protein of the extracellular matrix– were studied. The consequences on MC-3T3 cell adhesion to Fn coatings were also evaluated. We have demonstrated that nTiO2 cytotoxicity depends on their concentration, the cell type, and the chemical nature of the nanoparticle surface. The interaction of nTiO2 with Fn and the decrease of cell adhesion also depend on the concentrations and surface’s nature of nanoparticles. Moreover, our cytoxicity studies concerning pre-osteoblasts have shown a secretion of high levels of the pro-inflammatory cytokine IL-6, known to mediate osteolysis by osteoclast activation. Thus, our study highlights the urgent need to reconsider the use of nanostructured biomaterials and to determine if they could inhibit bone reconstruction
Bourouina, Nadia. "Colloïdes liquides pour la micro-actuation des interactions biologiques de surface : du système modèle à la cellule T". Paris 6, 2011. http://www.theses.fr/2011PA066238.
Texto completoSandrin, Ludivine. "Caractérisation des interactions biomoléculaires entre des ligands peptidiques immobilisés sur une surface et des récepteurs cellulaires". Phd thesis, Grenoble 1, 2009. http://tel.archives-ouvertes.fr/tel-00453636.
Texto completoDesrousseaux, Camille. "Prévention de l'adhésion bactérienne et du développement du biofilm sur les dispositifs médicaux de la perfusion via les surfaces nanostructurées". Thesis, Clermont-Ferrand 1, 2015. http://www.theses.fr/2015CLF1PP03.
Texto completoMedical device-related infections are a public health concern and an economic burden. The role of biofilms in medical device-related infections is clearly established. Preventive hygiene measures are not often sufficient to prevent biofilms formation. One promising way of preventing device-related infections is the development of medical devices with surfaces or materials that reduce either microbial viability using biocidal substances or microbial adhesion with topographical modifications.Developing nanostructured polymeric surfaces, which could have applications in medical devices, and testing their impact on bacterial adhesion and biofilm development were the main goals of this thesis. First of all, the polymer was replicated on an aluminum anodized oxide nanostructured mold (AAO), characterized by highly ordered nanopores. An anodization station was made in order to create molds. Then, the reproducibility of the process fabrication was validated (pore diameter: 51 ± 6 nm, deepness 97 ± 9 nm, interpore espace: 102 ± 6 nm). Several replication techniques with ABS were tested including polymers solutions and melted polymers. The selected method was the one with the most reproducible results pillar diameter: 56 ± 7 nm, interpillar distance: 101 ± 16 nm, length: 73 ± 33 nm) and the most representative of industrial injection processes. The created surfaces were then characterized (MEB, DSC, ATR-FTIR, wettability). The fabrication process does not seem to degrade the ABS material and the topographical change increases the hydrophilicity of the surface. A stability study showed that the nanopillars were resistant to several sterilization processes (ethylene oxide, H2O2 plasma, Beta irradiation) and were maintained through time, which is an important element for applications in medical-devices.The second step of our work consisted of assessing bacterial adhesion on control and nanostructured ABS samples. Several biofilm tests were made with S. epidermis in static and dynamic conditions. Between 3 and 48 hours of culture, bacteria were removed from the surfaces and then viable plate counting was performed. No significant differences were observed between the samples. Microscopic observations (MEB, CSLM) seemed to confirm this result. Other bacteria with different morphologies were tested (S. aureus, K. pneumoniae, P. aeruginosa): bacterial adhesion was similar for the two surfaces. Therefore, we can conclude that our developed ABS surfaces with these specific nanopillars do not have an anti-adhesion effect on the tested bacteria. Recent researches showed that spacing between nanopillars is a critical factor on bacterial adhesion. The following step of our work would be to test new nanostructures using AAO molds with bigger interpore distance
Hammache, Djilali. "Récepteurs glycolipidiques du VIH-1 à la surface des cellules CD4- (cellules épithéliales intestinales et spermatozoi͏̈des) et CD4+ (lymphocytes et macrophages) : analyse moléculaire des interactions virus-récepteurs au niveau des microdomaines de glycolipides reconstitués in vitro". Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30023.
Texto completoKhokhlova, Mariya. "Interactions of cells with oxide thin films". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC241.
Texto completoIn the present work we demonstrate how oxide thin films can be used as bioactive surfaces, a field of research which is still underexplored. For this purpose, thin films of TiO2, Al2O3, VOx and some others were deposited on glass substrates using the Pulsed Laser Deposition (PLD) technique, and adhesion, proliferation and differentiation of human bone marrow-derived mesenchymal stem cells were evaluated. Cell behavior was analyzed with respect to the various key surface parameters such as chemistry, wettability, morphology and the thickness of films.Our results indicate that thin films of TiO2 and Al2O3 can not only support mesenchymal stem cells adhesion and growth, but also can be used to influence osteogenic and chondrogenic differentiation path. Additionally, effect of oxide thin films on adhesion and growth of cancer cell lines was studied. We showed that culturing these cell lines on thin films affects their growth and, therefore, could be a valuable method to perform screening tests with drugs.This work will provide a better understanding of correlation between surface chemistry and cellular response, which has a high significance in the field of biomaterials fabrication
Dallanegra, Anne. "Étude de l'activation lymphocytaire dans l'environnement épidermique : régulation de l'expression de surface du complexe CD3/TCR et implications biologiques : rôle des cytokines dans les interactions entre les lymphocytes et les cellules épidermiques". Lyon 1, 1992. http://www.theses.fr/1992LYO1T182.
Texto completoStanciuc, Ana-Maria. "In vitro evaluation of cell-material interactions on bioinert ceramics with novel surface modifications for enhanced osseointegration". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI053/document.
Texto completoThe focus of this PhD thesis is the in vitro evaluation of cell-material interactions on bioinert ceramics with novel surface modifications for enhanced osseointegration of orthopaedic and dental implants. Firstly, alumina-zirconia surfaces with different micro-roughnesses obtained by injection moulding were studied. The behaviour of human primary osteoblasts (hObs) obtained from patients undergoing total hip replacements was studied on the different micro-rough ZTA surfaces and on combined micro-/nano-rough surfaces modified by hydrofluoric acid treatment. Micro-roughness alone had minor effects on hOb response while the combination micro-/nano-roughness induced a synergic effect on hOb maturation. This latter surface modification technique opens the way to the fabrication of ceramic acetabular cups with direct implantation capabilities. Secondly, robocasting (a 3D printing technique) was explored for the fabrication of a alumina-zirconia macroporous structures with high reproducibility and control of the architecture. Roughness at different scales was observed for the 3D structures due to the scaffold design and to the low temperature sintering conditions. Osteoblasts were able to attach on the 3D structures but cell retention at long term needs further optimization. Rapid screening of cell-material interactions was the subject of the last part of the thesis. Two different strategies were tested on zirconia: femtosecond laser to produce multiple patterns on a single sample and samples with a roughness gradient by the control of chemical etching time. Stem cell morphology was used as an early marker of cell differentiation lineage. In conclusion, the different surface modification techniques of zirconia and alumina-zirconia surfaces used in the thesis allow the modulation of cell-material interactions by stimulating stem cells osteogenesis and osteoblast maturation
Wang, Chao. "Renewable Natural Polymer Thin Films and Their Interactions with Biomacromolecules". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64909.
Texto completoPh. D.
Biagi, Sofia. "A mesoscale investigation of the endothelial glycocalyx and its interaction with blood flow". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY083/document.
Texto completoPolymer brushes are dense matrices of grafted macromolecules. In addition to brushes finely designed in laboratory, various examples are offered by Nature, as the endothelial glycocalyx, decorating the lumen of mammalian blood vessels. The interaction of such network with the flowing plasma and cells is still partially unknown.The present thesis, by mean of Dissipative Particle Dynamics simulations, proposes a coarse-grained model for the self-consistent analysis of a dense polymer brush under parabolic flow. Our mesoscale investigation highlights the relevance of collective effects, driven by hydrodynamics, and proposes novel interpretations regarding the rich phenomenology of the brush-flow system.Preliminary results are also provided for the interplay between a mesoscopic deformable flowing object (prototype of a red blood cell) and the grafted polymers
Peyrot, Tom. "Dipole dipole interactions in dense alkali vapors confined in nano-scale cells". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLO012/document.
Texto completoAlkali vapors confined in nano-scale cells are promising tools for future integrated atom-based sensor. In this thesis, we investigate the interaction between light and an ensemble of atoms confined in a nano-geometry. We focus on the different processes that can modify the optical response of the atomic ensemble and possibly affect the sensitivity of a sensor based on that technology. First, we study the non-local response of atoms to a light excitation due the atomic motion in thermal vapors. When the distance over which the atoms relaxes is larger than the size of the cell, the optical response depends on the size of the system. We have observed that for transmission spectroscopy, this leads to a periodic modification of the optical response with a period equal to the wavelength of the optical transition. Subsequently we showed that when the density of atom increases, the atomic response becomes local again. In this dense regime, the resonant dipole-dipole interaction in a sub-wavelength geometry leads to collective frequency shifts of the spectral lines. We demonstrate that these shifts were induced by the cavity formed by the cell walls, hence clarifying a long-standing issue. We developed a model to extract the density shifts deconvolved from the cavity effects. Close to a surface, the optical response is also affected by the van der Waals atom-surface interaction. We introduced a new method to extract precisely the strength of this interaction. We also developed a new generation of super-polished glass nano-cells and we presented promising spectroscopic signals. Finally, using these cells, we have compared transmission and off-axis spectroscopic techniques
DE, PARSEVAL AYMERIC. "Le virus de l'immunodeficience feline : regulation transcriptionnelle, role de la glycoproteine cd9 dans la replication virale, et interaction de la glycoproteine de surface (gp95) avec la cellule hote". Paris 7, 2001. http://www.theses.fr/2001PA077046.
Texto completoShetty, Pramod. "Study on Supramolecular Gel Lubricants". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76007.
Texto completoLintz, Michel. "MESURE DE LA VIOLATION DE LA PARITE SUR LA TRANSITION 6S-7S DU CESIUM PAREMISSION STIMULEE DANS UNE VAPEUR ATOMIQUE". Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00011127.
Texto completoBai, Hongjuan. "Bio-colloidal transfer in saturated and unsaturated porous media : influence of the physical heterogeneity of the porous medium and cell properties on bacteria transport and deposition mechanisms". Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2336/document.
Texto completoThe investigation of the transport and retention of bacteria in porous media has a great practical importance in environmental applications, such as protection of the surface and groundwater supplies from contamination, risk assessment from microorganisms in groundwater, and soil bioremediation. The aim of this study is to gain a fundamental understanding of the mechanisms that control bacteria transport and deposition in saturated and unsaturated porous media. Laboratory tracer and bacteria transport experiments at Darcy scale were performed in three porous media with distinct pore size distribution in order to investigate and quantify water and bacteria transport process under steady state flow conditions. A conservative solute was used as water tracer to characterize water flow pathways through porous media. A gram negative, motile Escherichia coli, a gram negative, non-motile Klebsiella sp. and a gram positive, non-motile R. rhodochrous were selected for the transport experiments. Characterization of cell properties (such as cell size and shape, zeta potential, motility and hydrophobicity) was performed for each strain. Numerical simulations with HYDRUS-1D code were performed to characterize water flow and to estimate bacteria transport and deposition parameters. The later were explored to identify bacteria flow patterns and physicochemical or physical mechanisms involved in bacteria deposition. To provide a better understanding of the mechanisms involved on bacteria transport and deposition, pore scale experiments were carried out by using microfluidic devices, designed for this purpose. The information obtained from laboratory experiments and numerical modeling was improved by theoretical calculation of different interactions between bacteria and porous media at air/water/solid interfaces. DLVO and non-DLVO interactions such as hydrophobic, steric, capillary and hydrodynamic forces involved in bacteria deposition were considered to describe bacteria-interface interactions in order to identify their relative impact on physicochemical and physical deposition of bacteria. Results obtained through both laboratory experiments and numerical simulationsoutlined non-uniform flow pathways, which were dependent on both grain/pore size as well as pore size distribution of the porous media. For a given porous medium, water flow patterns became more non-uniform and dispersive with decreasing water saturation due to the presence of air phase, which lead to an increase of the tortuosity of the flow pathways under unsaturated conditions. Bacteria transport pathways were different from the tracer transport, due to size exclusion of bacteria from smaller pore spaces and bacteria motility. Bacteria deposition was greatly influenced by pore network geometry, cell properties and water saturation degree. Both physical straining and physicochemical attachment should be taken into account to well describe bacteria deposition, but their importance on bacteria deposition is closely linked to porous media and cell properties. The results obtained in this work highlighted the simultaneous role of cell properties, pore size distribution and hydrodynamics of the porous media on bacteria transport and deposition mechanisms. The calculation of DLVO and non-DLVO interactions showed that bacteria deposition in saturated and unsaturated porous media was influenced by both kinds of interactions
Tavares, Lucas Alves. "O envolvimento da proteína adaptadora 1 (AP-1) no mecanismo de regulação negativa do receptor CD4 por Nef de HIV-1". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17136/tde-06012017-113215/.
Texto completoThe Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.
Fakhari, Tehrani Soudeh. "Propriétés de surface des nanoparticules et interactions avec les cellules endothéliales vasculaires". Thèse, 2019. http://hdl.handle.net/1866/23549.
Texto completoTo date, imaging and treatment of brain tumors are proved to be very inefficient due to the presence of the blood-brain barrier (BBB). The (BBB) is a semipermeable barrier which prevents or restrains most therapeutic and diagnostic molecules reach the central nervous system (CNS). Polymeric nanoparticles (NPs) loaded by therapeutics molecules and diagnostic agents could represent a promising solution to help active ingredients to cross the BBB and as a consequence, their biodistribution to the brain could be improved. Polymeric NPs composed of di-block copolymers, such as poly (ethylene glycol) blocks (PEG) that bind to polyester hydrophobic chains, are considered one of the most versatile nanocarriers for transporting therapeutic molecules across the BBB. PEG on the surface of NPs improves the NPs colloidal stability. Furthermore, PEG surface coating decreases the non-specific adsorption of proteins on the surface of NPs (also called opsonization); therefore, the clearance rate of the NPs is slowed down and NPs circulation times in blood is extended. Despite the beneficial effect of the PEG coating on the surface of NPs, the exact role of the surface properties related to the PEG chain length on NPs interactions with the vascular endothelial cells is poorly understood. In first article, the role of PEG chain length on brain vascular endothelial cells endocytosis and transcytosis is investigated on monolayers of bend.3 cells as an in vitro BBB model. The NPs transport mechanisms were then investigated by using different endocytosis inhibitory processes. Our results revealed that NPs endocytosis and transcytosis rates increased with PEG chain length. Higher endocytosis and transcytosis rates were observed for PLA-PEG5000 and PLA-PEG10000 NPs. Moreover, the mechanistic studies demonstrated that the PEG chain length influenced the endocytosis pathway taken by PEGylated NPs through an in vitro model of BBB. In second article, the effect of PEG length on NPs cytotoxicity and inflammatory processes has been investigated in two vascular endothelial cell lines (bEnd.3 and HUVEC). The effect of PEG chain length coating on gene expression that are involved in the inflammation response was investigated by qPCR. Moreover, the potential Reactive Oxygen Species (ROS) generation was evaluated with DCFH-DA probe. The results showed that PEGylated NPs induce a mild and transient activation of inflammatory cytokine and chemokine genes. However, the length of the PEG chains did not modulate significantly gene expression of inflammatory cytokines and chemokines. Furthermore, our results showed that PEGylated NPs did not induce ROS generation. In summary, the chain length of PEG influences the endocytosis and transcytosis rate. The pathway of endocytosis involved in internalization and transcytosis is influenced by the length of PEG chains. In contrast, differences in the length of PEG chains did not significantly modulate the expression of cytokines and inflammatory chemokines. These results contribute to develop nanoformulations that cross the BBB more efficiently while keeping the toxic and inflammatory effects minimal, particularly on the vascular endothelial cells of the BBB. Nevertheless, these perspectives have to be confirmed on in vivo models.
Pértile, Renata Aparecida Nedel. "Bacterial cellulose: studies on biocompatibility, surface modification and interaction with cells". Doctoral thesis, 2010. http://hdl.handle.net/1822/11194.
Texto completoA wide variety of biomaterials and bioactive molecules have been applied in tissue engineering as scaffolds in order to provide an appropriate environment to the growth and differentiation of cells. However, creating devices for biological substitutes that enhance the regeneration of neural tissues is still a challenge, because of the difficulty in providing an active stimulation of nerve regeneration. Biological scaffolds can be composed of natural polymers combined with extracellular matrix molecules and have been shown to facilitate the constructive remodeling of many tissues by the establishment of an environment necessary for the regulation of cell processes. In this context, different biomaterials have been used as scaffolds to improve interactions between material/cells and repair neurological damages. In recent years, bacterial cellulose (BC) emerged as a promising biomaterial in tissue engineering due its properties: high crystalinity, wettability, high tensile strength, pure nanofibers network, moldability in situ and simple production. BC has been modified to further enhance cell adhesion and biocompatibility; as an alternative to peptide chemical grafts, BC allow the use of recombinant proteins containing carbohydrates binding domains (CBMs), such as the CBM3, which has affinity by cellulose, representig a attractive way to specifically adsorb bioactive peptides on cellulose surface. The goal of this work was to modify the bacterial cellulose improving the neuronal cell affinity and producing a scaffold with potential to be used in neural tissue engineering. For this purpose, two strategies were used: 1) adhesive peptides fused to a carbohydrate binding domain with affinity to cellulose and; 2) surface modification by nitrogen plasma treatment. Also, in this work, we analized the biocompatibility in a longterm approach of two different types of BC grafts and the effect of BC nanofibers subcutaneously implanted in mice. The recombinant proteins IKVAV-CBM3, exIKVAV-CBM3 and KHIFSDDSSECBM3, were successfully expressed in E. coli, purified and stably adsorbed to the BC membranes. The in vitro results showed that the exIKVAV-CBM3 was able to improve the adhesion of both neuronal and mesenchymal cells (MSC), while IKVAV-CBM3 and KHIFSDDSSE-CBM3 presented only a slight effect on mesenchymal cell adhesion, and no effect on the other cells. The MSCs neurotrophin expression by cells grown on BC membranes modified with the recombinant proteins was also verified. NGF was expressed and released by cells adhered on the BC membranes, creating a microenvironment that promotes neuronal regeneration. The nitrogen plasma treatment did not increase the wettability of the material, but increased the porosity and changed the surface chemistry, as noticed by the presence of nitrogen. XPS analysis revealed the stability of the modified material along time and autoclave sterilization. The cell adhesion and proliferation of HMEC-1 and N1E-115 cells was significantly improved in the plasma treated BC, in contrast with the 3T3 cells, revealing a cell-specific effect. Regarding in vivo studies, the BC implants caused a low inflammatory reaction that decreased along time and did not elicit a foreign body reaction. A tendency for calcification, which may be related to the porosity of the BC implants, was observed. However, this tendency was different depending on the BC tested. Regarding nanofibers implants, after 2 and 4 months post implantation, mostly of injected nanofibers remained in aggregates in the subcutaneous tissue. There was infiltration of cells in these aggregates of nanofibers, mostly macrophages, and there is evidence of phagocytosis of the material by these cells. Moreover, no differences were observed between the controls and implanted animals in thymocyte populations, B lymphocyte precursors and myeloid cells in the bone marrow.BC is a good material to be used as scaffold in tissue engineering applications. However, is still necessary to improve the interaction of cells with the material to obtain a matrix that supports the growth, differentiation and selectivity of cells. In our attempt to enhance and select neuronal attachment to BC, the recombinant proteins produced were able to improve cell adhesion and viability on BC membranes. Also, nitrogen plasma treatment proved to be an effective and economical surface treatment technique, which was also capable to improve the adhesion of endothelial and neuroblast cells to the material. Therefore, the surface modification leads to a better cell affinity with BC, probably contributing for a better biocompatibility in vivo. In the in vivo results, our work points to the necessity to further investigation to verify the tendency to BC to calcify in long-term circumstances. Meanwhile, the BC nanofibers seem to be an innocuous material in mice subcutaneous tissue, and proved to be an eligible material to production of ECM-mimetic grafts.
Actualmente, um grande número de materiais poliméricos com diferentes propriedades estão disponíveis para aplicações biomédicas. Têm sido exploradas várias abordagens com o objetivo de melhorar a interação entre os polímeros e as células, que por ser geralmente inadequada, provoca reações in vivo como inflamações, perdas de tecido local e encapsulamento dos implantes. Entre estas abordagens, a modificação das superfícies, como por exemplo a funcionalização dos materiais com peptídeos imobilizados ou grupos químicos incorporados, mostra vantagens na obtenção de interações específicas das células com os materiais resultando em uma melhoria na sua biocompatibilidade. A celulose bacteriana (CB) tornou-se um biomaterial em foco para aplicações biomédicas devido a sua alta resistência mecânica, hidrofilicidade, alta cristalinidade e pureza, baixo custo de produção e sua característica rede de nanofibras. Além disso, o uso de domínios de ligação à celulose é uma alternativa simples e específica de enxertar peptídeos bioativos à estrutura da celulose possibilitando uma maior afinidade celular. O objectivo deste trabalho foi modificar a CB para aumentar a afinidade de células neuronais, produzindo um scaffold com potencial para ser utilizado em engenharia de tecidos neuronal. Com este propósito, duas estratégias foram utilizadas: 1) o uso de peptídeos de adesão conjugados a um domínio de ligação a carbohidratos (CBM), com afinidade para a celulose e, 2) modificação da CB através do tratamento com plasma de nitrogênio. Também, dentro do âmbito deste trabalho, avaliouse a biocompatibilidade a longo prazo da CB, tanto de implantes como de nanofibras implantados subcutaneamente em camundongos. As proteínas recombinantes IKVAV-CBM3, exIKVAV-CBM3 and KHIFSDDSSECBM3 foram expressas em E.coli, purificadas e adsorvidas de maneira estável nas membranes de CB. Os resultados in vitro mostraram que o exIKVAV-CBM3 aumentou a adesão de células neuronais e mesenquimais, enquanto que o IKVAV-CBM3 e KHIFSDDSSE-CBM3 apresentaram apenas um pequeno efeito na adesão das células mesenquimais, e nenhum efeito nas outras células testadas. Também, a expressão de neurotrofinas pelas células mesenquimais nas membranas de CB modificadas com as proteínas recombinantes foi verificada, e verificou-se que o NGF é expresso e libertado por estas células aderidas na CB, criando um ambiente promotor da regeneração neuronal. O tratamento com o plasma de nitrogênio não aumentou a molhabilidade da CB, mas foi capaz de aumentar a porosidade e a química de superfície, evidenciado pela presença do grupo nitrogênio. As análises de XPS mostraram a estabilidade do material modificado 180 dias após o tratamento, e após a esterilização por autoclave. A adesão e a proliferação celular das linhagens endotelial (HMEC-1) e neuronal (N1E-115) foi aumentada significativamente na celulose tratada com plasma, em contraste com os fibroblastos 3T3, o que revelou um efeito célula-específico. Quanto aos estudos in vivo, os implantes de CB causaram apenas uma reação inflamatória de baixa intensidade, que decresceu ao longo do tempo, e não estimulou reação de corpo estranho. Foi observada uma tendência para calcificar nas membranas de CB menos porosas, indicando uma relação com a porosidade dos implantes. Quanto aos implantes de nanofibras, após 2 e 4 meses de implantação, verificou-se que a maior parte das nanofibras permaneceram em agregados no tecido subcutâneo. Houve infiltração de células nesses agregados de nanofibras, sendo a maioria macrófagos, e evidências de fagocitose do material por estas células. Também, não foram encontradas diferenças entre os controles e os animais implantados nas populações de timócitos, precursores de linfócitos B e células mielóides na medula óssea. A CB é um bom material para ser utilizado em aplicações de engenharia de tecidos. Entretanto, ainda é necessário a modificação deste material para aumentar sua interação com as células, obtendo assim uma matriz capaz de manter o crescimento, a diferenciação e a seletividade de células. Na nossa tentativa de aumentar e selecionar a adesão de células neuronais à CB, as proteínas recombinantes produzidas foram capazes de aumentar a adesão e a viabilidade celular neste material. Também, o tratamento por plasma de nitrogênio provou ser um tratamento de superfície econômico e efetivo, sendo capaz de aumentar a afinidade das células com a CB, o que poderá contribuir para um melhoramento da sua biocompatibilidade in vivo. Quanto aos testes in vivo, este trabalho aponta para a necessidade de investigação futura para verificar a tendência da CB em calcificar em circunstâncias a longo prazo. Entretanto, as nanofibras de CB parecem ser inócuas quando implantadas no tecido subcutâneo, sendo um material elegível para a produção de enxertos que mimetizem a matriz extracelular.
Liao, Jinyu. "Probing Cellular Response to Heterogeneous Rigidity at the Micro- and Nanoscale". Thesis, 2017. https://doi.org/10.7916/D88K7H07.
Texto completoKapsabelis, Susan. "Polymer-particle interactions : adsorption of ethyl(hydroxyethyl)cellulose (EHEC) onto modified silica and pharmaceutical particle surfaces". 2001. http://arrow.unisa.edu.au:8081/1959.8/50784.
Texto completoHarrison, Nathan Daniel. "Nanoscale characterization of interactions between molecular specific plasmonic nanoparticles and living cells and its implications for optical imaging of protein-protein interactions". Thesis, 2009. http://hdl.handle.net/2152/ETD-UT-2009-12-556.
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Tham, YY. "Study of the interactions of softwood extractives and model compounds with different model surfaces". Thesis, 2016. https://eprints.utas.edu.au/23490/1/Tham_whole_thesis.pdf.
Texto completoJay, Anthony. "Studies of CD36 interacting with fatty acids, oxidized low-density lipoprotein, and the cellular plasma membrane". Thesis, 2017. https://hdl.handle.net/2144/20779.
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