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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Biokompatibilita implantabilních materiálů se zaměřením na titanové dentální implantáty / Biocompatibility of Implantable MaterialsFocused on Titanium Dental Implants

Moztarzadeh, Amin January 2017 (has links)
This dissertation thesis deals with the evaluation of biocompatibility and osseointegration of nanostructured titanium materials used for dental implants. Bulk material topography and surface modification of titanium are currently of intense research mainly due to the significant impact on biocompatibility and improvement of osseointegration of dental implants. In the theoretical part are described types of titanium material and different methods of its surface modification. In vitro and in vivo biocompatibility and osseointegration tests are described as well. The experimental work consists of two parts of experiments. In the first experiment, we examined how grain size of nanostructured titanium material influences the behaviour of fibroblastic as well as osteoblastic cells growth on its surface. The experimentally obtained data were statistically analysed and discussed. Grain size was proven to be an important factor that influenced not only the strength of material but also its interactions with cells. The second experiment describes current methods used in the experimental evaluation of osseointegration of dental implants. The results of histological staining methods are illustrated and compared. A standardized and reproducible technique for stereological quantification of bone-implant contact...
12

Obtention des structures polymériques dans le plasma pour applications médicales / Obtaining the polymeric structures in plasma for medical applications

Rusu, Bogdan-George 24 September 2013 (has links)
L'absorption des biomolécules, en particulier des protéines, sur les implants médicaux joue un rôle important dans le processus d'acceptation de l'implant dans le corps humain. L'activation des surfaces polymères par polymérisation plasma à pression atmosphérique et traitement plasma sont des méthodes utilisées dans les laboratoires des recherches pour modifier la cinétique d'adsorption et la quantité d'adsorbant. Le but de cette thèse est de mieux comprendre les mécanismes d'absorption des molécules biologiques sur des surfaces polymères modifiées par plasma à pression atmosphérique ou par autoassemblage, d'établir les mécanismes à l'interface et aussi d'établir la liaison entre la conformation des molécules adsorbées et les propriétés de biocompatibilité. / The objective of this thesis is to better understand the absorption mechanisms of biological molecules on surfaces obtained in plasma at atmospheric pressure or by self-assembly, to establish mechanisms at the interface and also establish the link between conformation of proteins adsorbed and the properties of biocompatibility.We studied a discharge at atmospheric pressure to obtain thin films of polyethylene glycol (PEG) and polyethylene glycol (PEG) with polystyrene copolymer. The characterization of thin polymer films was made using techniques atomic force microscopy (AFM), scanning electron microscopy (SEM), the contact angle measurements, infrared spectroscopy with Fourier transform (FTIR ) and X-ray photoelectron spectroscopy (XPS). The surfaces were analyzed in terms of biomolecules absorption with atomic force spectroscopy and quartz crystal microbalance.Studies of the ions and amino acids diffusion through functionalized mesoporous structures by low-pressure plasma are presented. After functionalization, we demonstrate the selectivity of the membrane for a particular class of amino acid, those which have a hydrophilic character.The mechanisms of self-assembly and stabilization of the G type molecules inside of the porous silicon are shown. Because the optical properties of these types of surfaces it can be observed the differences in stability of these molecules on the ionic strength of the different ion which form the structures.
13

Korrelation der makroskopischen Alterung mit nanoskaligen Veränderungen in hybriden Polymer/Zement-Oberflächenaktivierungen für Glasfaserrovings in Textilbeton

Hojczyk, Markus, Weichold, Oliver, Walther, Andreas, Möller, Martin 03 December 2011 (has links) (PDF)
Hybride Oberflächenaktivierungen von Glasfaserrovings mittels Polymer/Zement-Kompositen ermöglichen eine komplette Durchdringung des Rovings mit Beton von der Matrix bis zu den innenliegenden Einzelfilamenten. Dies erlaubt einen deutlich verbesserten Lasteintrag in den gesamten Rovingquerschnitt bei der Verwendung als Faserverstärkung in textilbewehrten Betonen. Auf Grund von ausgeprägten Domänen hydratisierter Zementsteinphasen innerhalb des Rovings ergibt sich eine komplexe, multiskalige Verbundstruktur, die sich in ihren Eigenschaften deutlich von klassischen polymerbeschichteten Rovings unterscheidet. Wir diskutieren diesen Ansatz in Bezug auf Herstellung, nano-/mikroskopische Charakterisierung, sowie der mechanischen Eigenschaften der Probenkörper unter beschleunigten Alterungsbedingungen. Die mikroskopischen Untersuchungen mittels höchstauflösender Elektronenmikroskopie und Nanoindentation zielen darauf ab, die Grenzflächenanbindung, die veränderte Struktur in Abhängigkeit des verwendeten Polymers und der Additive sowie die Korrosionsmechanismen aufzuklären. / Hybrid surface modifications of glass fiber rovings with polymer/cement-composites allow the generation of extended cement phases within the roving and an activation of the innermost filaments to the surrounding concrete matrix. This enables enhanced load transfer across the full roving cross section when used as fibrous reinforcement in textile-reinforced concrete. Due to the presence of extended concrete domains within the roving, a complex multiscale composite structure develops, displaying distinctly different properties as compared to standard polymer impregnation routes. We discuss this approach in terms of production, nano/microscopic characterization of the concrete composites and mechanical properties of the resulting specimens under accelerated aging conditions. The microscopy studies using highest resolution electron microscopy and nanoindentation aim to elucidate the interface connection, the changes in morphology of the concrete as a function of the polymer and additives used, as well as shedding light on the corrosion mechanisms.
14

Vliv modifikovaných TiO2 nanotrubiček na interakce na biorozhraní / The influence of modified TiO2 nanotubes on biointerfacial interaction

Bílek, Ondřej January 2021 (has links)
Nanotrubičky oxidu titaničitého v průběhu posledních let nabyly na významu v poli biomedicíny. Jakožto biokompatibilní nanostrukturovaný povrch nachází potenciál pro své uplatnění především v oblasti implantačních aplikací. Teoretická část této práce je tak věnována různým přístupům pro syntézu TiO2 nanotrubiček, jejich modifikacím a aplikacím v biomedicíně. Experimentální část pak pojednává o nanotrubičkách oxidu titaničitého, které jsou připraveny z titanu metodou jednokrokové anodické oxidace v organickém elektrolytu. Jako výchozí materiály jsou používány křemíkové disky s naprášenou vrstvou titanu a titanové folie. Zprvu amorfní nanotrubičky jsou žíháním převedeny na svou krystalickou podobu, a následně modifikovány selenovými a stříbrnými nanočásticemi. Připravené struktury jsou zkoumány z hlediska povrchových vlastností a biologických interakcí s vybranými tkáňovými kulturami (MG-63, NIH-3T3) a bakteriemi (E. coli, P. aeruginosa, S. aureus). V závěru experimentální práce jsou stručně porovnány výsledky selenových a stříbrných nanočástic. Hlavním cílem této práce je rozšířit znalosti týkající se bio-rozhraní tvořeným adherentními buněčnými liniemi, bakteriálními buňkami a nanostrukturovaným povrchem tvořeným TiO2 nanotrubičkami dekorovanými selenovými a stříbrnými nanočásticemi.
15

Cílené biokompatibilní nanočástice pro terapii a diagnostiku rakoviny. / Targeted biocompatible nanoparticles for therapy and cancer diagnostics.

Neburková, Jitka January 2018 (has links)
Nanoparticles (NPs) have considerable potential in targeted medicine. NPs can merge various functions and serve as labels for imaging or as nanocarriers in therapy. Modification of NPs with targeting ligands can lead to highly specific interactions with targeted cancer cells. However, the efficacy of targeting depends on the ratio between specific and non-specific interactions of a NP with the cell. Non-specific interactions of NPs are unrelated to targeted receptors and need to be eliminated in order to decrease background noise during imaging and adverse effect of drugs on healthy tissues. In this thesis, surface modifications of NPs were explored mainly on biocompatible carbon NPs called nanodiamonds (NDs), which have exceptional fluorescent properties such as long fluorescence lifetime, no photobleaching and photoblinking and sensitivity of their fluorescence to electric and magnetic field. Main issues addressed in this thesis are low colloidal stability of NDs in buffers and media, their non-specific interactions with proteins and cells and limited approaches for ND surface modifications. These issues were solved by coating NDs with a layer of biocompatible, hydrophilic, and electroneutral poly(ethylene glycol) or poly[N-(2- hydroxypropyl) methacrylamide] polymers. Optimized polymer coating...
16

Korrelation der makroskopischen Alterung mit nanoskaligen Veränderungen in hybriden Polymer/Zement-Oberflächenaktivierungen für Glasfaserrovings in Textilbeton

Hojczyk, Markus, Weichold, Oliver, Walther, Andreas, Möller, Martin January 2011 (has links)
Hybride Oberflächenaktivierungen von Glasfaserrovings mittels Polymer/Zement-Kompositen ermöglichen eine komplette Durchdringung des Rovings mit Beton von der Matrix bis zu den innenliegenden Einzelfilamenten. Dies erlaubt einen deutlich verbesserten Lasteintrag in den gesamten Rovingquerschnitt bei der Verwendung als Faserverstärkung in textilbewehrten Betonen. Auf Grund von ausgeprägten Domänen hydratisierter Zementsteinphasen innerhalb des Rovings ergibt sich eine komplexe, multiskalige Verbundstruktur, die sich in ihren Eigenschaften deutlich von klassischen polymerbeschichteten Rovings unterscheidet. Wir diskutieren diesen Ansatz in Bezug auf Herstellung, nano-/mikroskopische Charakterisierung, sowie der mechanischen Eigenschaften der Probenkörper unter beschleunigten Alterungsbedingungen. Die mikroskopischen Untersuchungen mittels höchstauflösender Elektronenmikroskopie und Nanoindentation zielen darauf ab, die Grenzflächenanbindung, die veränderte Struktur in Abhängigkeit des verwendeten Polymers und der Additive sowie die Korrosionsmechanismen aufzuklären. / Hybrid surface modifications of glass fiber rovings with polymer/cement-composites allow the generation of extended cement phases within the roving and an activation of the innermost filaments to the surrounding concrete matrix. This enables enhanced load transfer across the full roving cross section when used as fibrous reinforcement in textile-reinforced concrete. Due to the presence of extended concrete domains within the roving, a complex multiscale composite structure develops, displaying distinctly different properties as compared to standard polymer impregnation routes. We discuss this approach in terms of production, nano/microscopic characterization of the concrete composites and mechanical properties of the resulting specimens under accelerated aging conditions. The microscopy studies using highest resolution electron microscopy and nanoindentation aim to elucidate the interface connection, the changes in morphology of the concrete as a function of the polymer and additives used, as well as shedding light on the corrosion mechanisms.
17

Conception de nouvelles surfaces à propriétés antibactériennes / Design of surfaces in order to achieve antibacterial properties

Bedel, Sophie 08 December 2014 (has links)
La biocontamination des surfaces et les risques associés sont des enjeux majeurs économiques et de santé publique. Afin de limiter ou empêcher l’adhésion bactérienne, une des solutions possible consiste en la modification des propriétés des surfaces, afin de leur conférer les fonctions voulues. Dans ce contexte, l’objectif de cette étude est de modifier des surfaces de types métallique (acier) ou polymère : poly(téréphtalate d’éthylène) par des glycomonomères ou des monomères bioactifs. La stratégie de modification des surfaces s’effectue en plusieurs étapes.La première étape permet d’incorporer des fonctions réactives sur les surfaces par traitement acide puis réaction avec la dopamine, ou par traitement plasma ammoniaque. Des fonctions hydroxyle et amine sont introduites. Par la suite un amorceur de polymérisation par transfert d’atome est greffé sur les surfaces. Les monomères sont synthétisés et leur polymérisation étudiée en solution, dans un premier temps dans les conditions de polymérisation radicalaire classique, puis par polymérisation par transfert d’atome. Les conditions optimales sont déterminées, puis les polymérisations sur surfaces effectuées. La dernière étape concerne l’étude des propriétés microbiologiques des surfaces synthétisées.Les glycopolymères protégés et déprotégés de galactose ainsi que les polymères de méthacrylate de gaïacyle et de méthacrylate de thymyle ont été synthétisés. Les monomères ont été polymérisés par polymérisation par transfert d’atome à partir de la surface, sur les surfaces d’acier et de poly(téréphtalate d’éthylène). Après chaque étape de modification de surface, les matériaux ont été systématiquement caractérisés par goniométrie et spectroscopie à photoélectrons X. Les surfaces d’acier fonctionnalisées par le glycopolymère présentent des propriétés anti-adhésives vis-à-vis de Bacillus subtilis, un effet plus marqué est observé après greffage du glycopolymère déprotégé. Les surfaces de poly(téréphtalate d’éthylène) quant à elles, possèdent des propriétés anti-adhésives leur du greffage du poly(méthacrylate de thymyle) vis-à-vis de Listeria monocytogenes, Staphilococcus aureus et Pseudomonas aeruginosa. Un effet anti-biofilm a également été mis en évidence vis-à-vis de Staphilococcus aureus.En parallèle des homopolymères d’ammonium quaternaire et des copolymères obtenus en incorporant les monomères bioactifs ont été synthétisés. Les propriétés antibactériennes sont testées en milieu planctonique vis-à-vis de Bacillus subtilis. Un degré de polymérisation égal à 78 et les groupements halogénoalcane : iodométhane ou bromoéthane permettent l’obtention de la concentration minimale inhibitrice la plus faible. La présence des monomères bioactifs permettent la diminution de la concentration minimale inhibitrice. Le résultat le plus intéressant est obtenu lors de l’incorporation d’un pourcent de N-(4-hydroxy-3-méthoxy-benzyl)-acrylamide. / Bio-contamination of surfaces and related risks are very important economically and for public health. To prevent this phenomenon, one solution is to modify the properties of the surfaces, in order to give them the wanted functionalities. The goal of this study is the modification of metallic surfaces (steel) or polymer surfaces: poly(ethylene terephtalate) with glycomonomers or bioactives monomers. To reach this objective, a multi-step strategy is applied.The first step enabled the incorporation of reactive species on the surfaces by an acid treatment followed by a reaction with dopamine, or by ammonia plasma treatment. Hydroxyl or amine functional groups are added. Then, an initiator of atom transfer radical polymerization is grafted on surfaces. Monomers are synthesized and conventional polymerization and atom transfer radical polymerization are studied. Optimal conditions are determined and polymerization on surfaces achieved. The last step is the study of the microbiological properties of the synthesized surfaces.Protected and unprotected galactose glycopolymers as well as gaiacyl methacrylate and thymyl methacrylate have been synthesized. Monomers have been polymerized by atom transfer radical polymerization directly to the steel or poly(ethylene therephtalate) surfaces. After each step, materials are analyzed by contact angle measurements and X-ray photoelectron spectrometry.Steel surfaces which are functionalized by a glycopolymer and tested in presence of Bacillus subtilis are found to have antiadhesive properties. A most important effect is observed with the unprotected glycopolymer. Poly(ethylene terephtalate) surfaces have antiadhesive properties in presence of Listeria monocytogenes, Staphilococcus aureus and Pseudomonas aeruginosa when poly(thymyl methacrylate) is grafted. An antibiofilm effect is observed with Staphilococcus aureus.Simultaneously, quaternary ammonium homopolymers and copolymers by integration of bioactive monomers have been obtained. Their antibacterial properties are tested in planctonik conditions in presence of Bacillus subtilis. A degree of polymerization equal to 78 and alkyl halide groups: iodomethane and bromoethane enabled to obtain the lowest minimal inhibitory concentration. Bioactive monomers contributed to emphasize this decrease. The most decreasing effect is obtained when one per cent of N-(4-hydroxy-3-méthoxy-benzyl)-acrylamide is integrated.

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