An efficient delivery system and patient compliance are two of the most important factors for any drug delivery system design to be successful. The current standard, particularly to the ocular anterior segment, are topical applications including eye drops. However, due to ocular physical barriers including blinking, the varying tear film layers, and the structure of the corneal epithelium, less that 5% of drug reach the target tissue from a single eye drop dose. While most treatment regiments combat this with increased frequency of dosage and higher than needed concentrations, the need for a more efficient and controlled system has been recognized to reduce the risk of possible side effects. Contact lenses (CL) have been a widely discussed potential drug delivery device given their accepted use in the population, their ability to hold drug, as well as their placement on the ocular surface. The current work focuses on testing a novel delivery system using CLs with the incorporation of drug specific oligonucleotide chains known as aptamers on the surface of the lenses. This application of contact lenses is aimed at capitalizing on the strong affinity of aptamers to hold drug on the surface of the lenses until they are applied to the eyes. The aptamers were covalently attached to the surface via the activation of the hydroxyl groups on pHEMA as a model lens material using 1’1-carbonyldiimidazone CDI chemistry and subsequent reaction with the amine group on the 5' end of the aptamer. The presence of aptamers was confirmed using 6-carbofluorescein (6-FAM) fluorescence detection and x-ray photoelectron spectroscopy (XPS). The release of kanamycin B in comparison to regular pHEMA gels using a soaking uptake method was assessed. In this work, aptamers were confirmed through fluorescence to have been successfully reacted onto the surface, however XPS was not able to confirm a consistent reading. This may have been due to low initial amounts of aptamer or uneven distributions along the surface. The efficiency of the aptamer reaction was not tested and would need to be further investigated. The contact angle had a significant change with increased hydrophilicity at 60.7 ± 1.55° compared to 66.6 ± 0.67°, however physically it should not affect wettability. The lower aptamer amounts resulted in no significant difference during drug release. Kanamycin B was detected using liquid chromatography mass spectroscopy (LCMS) with a reverse phase method using a C18 column however quite a few errors in the methodology led to the conclusion that this method of drug release requires further investigation. It is recommended an aptamer-surface reaction efficiency be determined with the use of a much larger starting aptamer amount, as well as a follow up drug release. / Thesis / Master of Applied Science (MASc)

Hydrophilic poly(2-hydroxyethyl methacrylate), PHEMA, and hydrophobic poly(dimethyl siloxane), PDMS, segments containing copolymers have been widely used as a biomaterial. These amphiphilic copolymers also used as an emulsifying agent in polymer solutions and compatibilizer in polymer blends. In this case, solution polymerizations of HEMA by radiation, ATRP and RAFT methods were studied. The thermal degradation mechanism of PHEMA, which was prepared in aqueous solution by gamma radiation technique, was studied in detail. The DSC, TGA and Mass Spectroscopy analyses revealed that the degradation is linkage and depolymerization with a combination of monomer fragmentation. The ATRP of HEMA was performed with ethyl-2-bromoisobutyrate (EBriB) initiator and CuCl/bipyridine catalyst in MEK/1-propanol solvent mixture. Cu(II) complexes and PHEMA obtained via ATRP were characterized by UV-vis, FTIR and 1H-NMR analysis. The RAFT polymerization of HEMA with different [RAFT]/[AIBN] ratios were also investigated in three solvents (methyl ethylketone, ethyl acetate and toluene). The controlled polymerization of HEMA with the ratio of [RAFT]/ [AIBN]=18 at 80 oC in MEK and ethyl acetate, shows the first-order kinetic up to the nearly 40 % conversion Macroazoinitiator PDMS-MAI was synthesized from bifunctional PDMS and then copolymerized with MMA, EMA, HEMA and TMS-HEMA monomers Different characterization methods such as FTIR, 1H-NMR, solid state NMR, GPC, XPS, SEM, DSC, etc. have been used for the characterization of block copolymers. P(DMS-b-TMSHEMA) was converted to the P(DMS-b-HEMA) block copolymer by deprotection of TMS groups. The phase separated morphology was observed for the P(DMS-b-HEMA) copolymer, which was different from P(DMS-b-MMA) and P(DMS-b-EMA) copolymers.

Polymer composites containing nanosized fillers have generated explosive interest since the early 1980's. Many recent studies have been conducted incorporating nano-fillers into polymer matrices to design and synthesize materials with tunable mechanical, thermal, and optical properties. Conventional filled polymers, where the reinforcement is on the order of microns, have been replaced by composites with discrete nanosized fillers. Gradually, theories that predicted that composite properties are independent of particle size in the micron range were challenged by nanocomposites. Rather, nanocomposite properties are greatly influenced by the surface area of the. All of this is complicated by the fact that nanoparticles are inclined to aggregate or migrate to interfaces. Much effort has been devoted to optimize dispersion of nanofillers in the polymer matrices, as polymer-nanoparticle interactions and adhesion greatly influence performance of the material. A well- dispersed composite system with various noncovalent interactions such as those that arise from hydrogen bonding, electrostatic attractions and π-π interactions between the filler and the matrix, can transfer stress and the interface will stop the development of cracks and impede stress concentrations. Overall, large reinforcement increases are noted at low nanoparticle loadings. Additionally, functional properties such as thermal, electrical conductivity and porosity can be tailored for specific applications. The design of high performance composites requires optimizing dispersion, nanoparticle-polymer noncovalent interactions and the chemistry of the materials. Therefore polymer composites with different types of nanofillers were investigated to prove various noncovalent interaction and to improve the mechanical, thermal and electrical properties in this study. Poly (methyl methacrylate) (PMMA) with BaTiO3 and Bi2O3 composites were fabricated by two different methods; sonication of fillers in PMMA and in situ polymerization. Samples were irradiated in air via a JL Shepherd Mark I cesium-137 source. The dose rate was 985 rads/min and the total dose was 2.0 Mrad. The polymer sonication (PSON) method has a greater effect than in situ polymerization on sample uniformity. With the PSON method there was a slight improvement in rad hardness in the barium titanate composites. This is the case with and without MWNTs and coupling agents. The storage modulus and loss modulus were measured via Dynamic Mechanical Analyzer (DMA) under the tension film mode using a heating rate of 5 °C min-1 from -150 °C to 200 °C and a scanning frequency range of 1-100 Hz. Scanning electron microscopy (SEM) provided images of the polymer-nanocomposites. An aliphatic isocyanate, polyether, polyol thermoplastic polyurethane, Tecoflex® SG-85A, was solution processed with the varying amounts of silica nanowire. A new grade polyurethane, Tecoflex®, was synthesized from the aliphatic 4,4-methylene dicyclohexyl diisocyanate (H12MDI) with polytetramethylene ether glycol. Despite Tecoflex®'s longevity and wide use, this polymer's dielectric behavior has not been widely studied. Therefore, the dielectric response of neat PU, Tecoflex®, and PU composites with silica nanowire from -150 to 150 °C is presented. The mechanism of nanowire growing with diameters ranging from 50 to 500 nm has been established to follow the vapour liquid solid (VLS) model via the PtSi phase acting as the catalyst. Our previous thermal stability study of PU nanowire composites have yielded increased heat stability to 330 °C. In comparison, neat PU only maintains thermal stability in temperatures that range to 250 °C. The onset of decomposition temperature was measured by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) provided images of the polymer-nanocomposites. A series of PMMA-dodecyloxy NB and PHEMA-dodecyloxy NB composites were synthesized in situ and characterized. The dodecyl groups significantly alter the solubility of the nanoballs, imparting hydrophobicity to the surface of the nanoball. A comparison study was made between the PMMA-NB and PHEMA-NB nanocomposites. Structure property relations are discussed in terms of interactions between the polymer matrices and nanoball surfaces and interiors. These OC12 NB and the hydroxyl NB polymer composites are the first studies to date that probe relaxations and conductivity in discrete polyhedral metal-organic polymer composites. A novel ultra-flexible polycarbonate-polyurethane (PCPU) was synthesized with methylene bis(4-cyclohexylisocyanate), 1,4 butanediol as a chain extender and a polycarbonate polyol containing 1,6-hexanediol and 3-methyl-1,5-pentanediol. Through the techniques of water coagulation, the synthesis of self-healing PCPU with various concentrations of SWNT (Single-Walled Nanotubes) is possible. The resulting features of this synthesized rubber-like substance are to be evaluated to determine glass transition temperature. This novel type of polyurethane material targets growing markets for biocompatible polymers. Also, a secondary goal of this project is to obtain information useful to determining whether PCPU-carbon nanotube composites would be good candidates for use as a gel electrolyte in polymer batteries. All nanocomposites were characterized by differential scanning calorimetry (DSC) to determine glass transition temperatures. The dielectric permittivity (ε’) and loss factor (ε”) were also measured via Dielectric Analysis (DEA) in the frequency range 1Hz to 100 kHz and between the proper temperatures in all polymer composite. The electric modulus formalism was used to reveal structural relaxations including conductivity relaxation. The activation energies for the relaxations are presented.