This thesis makes several contributions towards tailored surfaces that can be used to guide biological growth. In Chapter 2 we synthetized and tested a new series of surfaces that can increase cell growth by 40%. Additionally, this chapter demonstrates that there is a very fine line between a cell's affinity towards the surface and the affinity of any biologically relevant ligands to their extracellular targets. Contrary to what seems intuitive, optimal control comes from regimes where cells have poor growth with ligands that possess only moderate affinity for their receptors. These are the conditions that provide the highest degree of photo-control over biological growth.To help build on the discoveries documented in Chapter 2, in Chapter 3 we designed and validated a new method of rapidly fabricating structurally diverse azobenzene chromophores. While the synthesis portion of Chapter 2 took almost a year to complete a single polymer, using the techniques developed in Chapter 3 each variant could be synthesized and purified within 48 hours, a remarkable improvement over existing techniques. We validated this with 17 derivative chromophores and showed that they retain their photophysical characteristics after functionalization, providing an additional element of control over the half-life and colour of actuation when preparing new azobenzene bio-materials. In Chapter 4 we expanded on the work of Chapter 3 in designing and testing novel faster-switching green-absorbing azo chromophores. These new ortho-nitro azobenzenes retain the characteristics that make Disperse Red 1 one of the most high-performing azo dyes in the literature and allow for the 'head' group to be easily functionalized. We tested the photophysical changes these chromophores experience in small molecule, monomer, homopolymer and copolymer forms providing important information on the trends in the colour and half-life of the chromophore in the different functionalized forms. We show that homopolymer forms experience a decrease in half-life yet show retention of their colour. The copolymer forms exhibit a bi-exponential half-life which we attribute to chain entanglement and experience a slight red-shifting in their absorbance. In all cases, the desired properties of the dyes are retained through the varied macromolecular architectures, demonstrating that this is a valid strategy to explore photomechanical issues in materials science, as well as develop new materials to guide biological growth using physical photo-induced features.In Chapter 5 we demonstrate how we developed a new surface functionalization which allows for the shedding of polymeric coatings with visible light. Using nitrobenzyl ethers we developed a new protocol to covalently attach this coating to carboxylated polystyrene beads providing a way to shed the outermost negative charge. When these beads are coated with poly-D-lysine, we show that we can trigger full release of beads adhered in cell culture. This will be useful in creating, as well as studying, tailor-made nerve connections and may hold applications for other materials. / Cet ouvrage présente la conception et la préparation de molécules et de polymères photoresponsifs compatibles avec des systèmes biologiques. L'utilisation de chromophores de type azobenzene et d'éther de nitrobenzyl, en tant qu'unité structurale dans un système polymérique ou en conjonction avec des polymères biocompatibles, a permis le développement de systèmes responsifs aux stimuli de lumière et permettant de guider la croissance biologique. Après irradiation par la lumière de surfaces de polyélectrolytes multicouches, contenant des chromophores d'azobenzene fonctionnalisées avec les peptides RGD et c(RGDfK), une augmentation de 40% de la croissance cellulaire fut observée. Il s'agit de la première démonstration de l'utilisation de ces surfaces multicouches pour le contrôle réversible de la croissance cellulaire grâce aux chromophores d'azobenzene. Pour faciliter de subséquentes découvertes dans le domaine des systèmes biocompatibles, une nouvelle méthodologie synthétique basée sur la «chimie click» fut développée. Celle-ci permet de diminuer le temps nécessaire à la synthèse des chromophores d'azobenzene structurellement diversifiés. Dix-sept différents chromophores ont été synthétisés grâce à celle-ci, et ont permis de démontrer, dans tous les cas, le maintien des propriétés photo-physiques. Cette technique fut aussi utilisée pour la synthèse d'un chromophore ortho-nitro azobenzoïque à isomérisation rapide et absorbant dans la région verte du spectre lumineux. Cette dernière molécule démontre ainsi la polyvalence du procédé et son utilisation possible dans le design de nouvelles surfaces visant l'enrichissement de la science des matériaux par-delà les surfaces biocompatibles. Finalement, nous avons développé un protocole de fabrication de revêtements multicouches contenant la fonctionnalité éther de nitrobenzyl. Ce revêtement peut libérer sa surcouche de poly-D-lysine après l'adhésion d'un neurone à sa surface. La manipulation mécanique par une bille portant ce revêtement, suivi du relâchement du neurite, rend possible la construction du réseau neuronal envisagé.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.121164 |
| Date | January 2014 |
| Creators | Goulet-Hanssens, Alexis |
| Contributors | Christopher Barrett (Supervisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | Electronically-submitted theses |
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