This thesis describes a number of novel experiments contributing to the understanding of protein adsorption from both a fundamental and applied perspective. The first three papers involve the use of the localized surface plasmon resonance of gold nanospheres to measure protein conformational dependencies during heat and acid denaturation. Thermal denaturation of BSA is shown to proceed differently depending on the size of nanosphere to which it is conjugated. Activation energies are extracted for thermal denaturing on nanoparticles. These energies decrease with decreasing radius of curvature. Under pH perturbation in the acid region, the multiple transition states of bulk BSA are suppressed, and only one apparent transition around pH 4 is evident. Smaller spheres (diameter < 20nm) do not exhibit any transition. A significant finding of all three studies is that the state and stability of BSA depends strongly upon local curvature. The last two papers investigate protein adsorption relevant to the biomaterial field. Investigation of protein adsorption to polyHEMA hydrogels is carried out using a quartz crystal microbalance. Single and mixed protein adsorption kinetics for BSA, lysozyme and lactoferrin are extracted and interpreted. Selected commercial cleaning solutions are shown to be no more effective than simple buffer solution. Examination of commercial lenses indicates that the morphology of adsorption is material dependent and that siloxane-based hydrogels only deposit low levels of protein. A unique fibril-like morphology is identified on galyfilcon A. Protein morphology is discussed in terms of bare lens morphology, roughness, and surface composition.

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.

This thesis describes a number of novel experiments contributing to the understanding of protein adsorption from both a fundamental and applied perspective. The first three papers involve the use of the localized surface plasmon resonance of gold nanospheres to measure protein conformational dependencies during heat and acid denaturation. Thermal denaturation of BSA is shown to proceed differently depending on the size of nanosphere to which it is conjugated. Activation energies are extracted for thermal denaturing on nanoparticles. These energies decrease with decreasing radius of curvature. Under pH perturbation in the acid region, the multiple transition states of bulk BSA are suppressed, and only one apparent transition around pH 4 is evident. Smaller spheres (diameter < 20nm) do not exhibit any transition. A significant finding of all three studies is that the state and stability of BSA depends strongly upon local curvature. The last two papers investigate protein adsorption relevant to the biomaterial field. Investigation of protein adsorption to polyHEMA hydrogels is carried out using a quartz crystal microbalance. Single and mixed protein adsorption kinetics for BSA, lysozyme and lactoferrin are extracted and interpreted. Selected commercial cleaning solutions are shown to be no more effective than simple buffer solution. Examination of commercial lenses indicates that the morphology of adsorption is material dependent and that siloxane-based hydrogels only deposit low levels of protein. A unique fibril-like morphology is identified on galyfilcon A. Protein morphology is discussed in terms of bare lens morphology, roughness, and surface composition.

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.

Développer un matériau pour une application dans le domaine des lentilles de contact nécessite de satisfaire plusieursexigences, notamment sur la transparence optique, sur la stabilité chimique et thermique. En outre, puisque le matériauest directement en contact avec le tissu de l'oeil, il doit être mouillable, biocompatible, résistant à l'encrassementbiologique, et perméable à l'oxygène. La perméabilité à l'oxygène (Dk) est un paramètre important pour la conceptionde lentilles de contact. Ce paramètre représente la facilité qu’aura l’oxygène à diffuser à travers la lentille vers l’oeil.Dans ce contexte, nous décrivons deux voies de recherche sur une nouvelle formulation afin de répondre à ces critères. Dans une première approche, cette recherche est axée sur la synthèse d’hydrogels de morphologie spécifique, en particulier, sur la synthèse simultanée et/ou séquentielle de réseaux polymères interpénétrés (IPN) permettant d’obtenir unemorphologie à phases co-continues. Parmi les nombreux monomères biocompatibles, nous nous sommes focalisésinitialement sur la combinaison d'un acrylate fluoré (2,2,2 -trifluoroéthyl méthacrylate, TFEM) et de la 1 -vinyl-2 -pyrrolidone (NVP), ce système étant comparé à un IPN constitué d’un monomère siloxane (3-[tris (triméthylsiloxy)-silyle] méthacrylate de propyle], TRIS), bien connu dans le domaine des lentilles de contact en raison de ses bonnes propriétés de transport de l'oxygène. Dans une deuxième approche, ces systèmes sont considérés comme une référence et nous avons prospecté l’élaboration d’IPN à base d’alginate et d’acrylamide, ces hydrogels ayant démontré des propriétés attractives, en particulier les propriétés mécaniques. Plusieurs formulations de gels ont été préparées et l'influence de leur composition sur les propriétés d’intérêt est décrite. En effet, ces hydrogels sont caractérisés d’un point de vue chimique par spectroscopie IRTF, chromatographie couplée GC-MS et d’un point de vue morphologie par microscopie MEB afin de mettre en évidence une morphologie avec des phases co-continues. Les propriétés mécaniques sont aussi déterminées. La perméabilité à l’oxygène étant en partie liée aux propriétés de gonflement du gel, la calorimétrie différentielle à balayage (DSC) a permis de déterminer et de quantifier l’eau absorbée dans ses différents états thermodynamiques et ces données sont reliées aux mesures de perméabilité. Une autre partie de ce projet est centrée sur la simulation numérique des hydrogels et de leurspropriétés physico-chimiques telles que le gonflement dans l’eau et la diffusion de molécules de gaz. Nous avons utilisé la méthode de dynamique moléculaire (MD) avec le champ de force COMPASS afin de modéliser les polymères les plus communs dans le domaine des lentilles de contact. / To design a material for contact lens application, the candidate materials must satisfy several requirements, including theoptical transparency, the chemical and thermal stability. In addition, since the material is directly in contact with the eyetissue, it should be tear wettable, biocompatible, biofouling resistant and oxygen permeable. Oxygen permeability (Dk) isan important parameter for the contact lens design as it is representative of the lens ability to diffuse oxygen at the eye.In this context, we are following two ways for a new formulation answering to these constrains. First, this research is focusedon the simultaneous or two-step synthesis of IPNs (interpenetrating polymer network) as a means to obtain a cocontinuousphases structure. Among the available biocompatible monomers, the work was initially focused on the achievement of IPN's based on a fluorinated acrylate - TFEM (2,2,2-trifluoroethyl methacrylate) and the 1 -vinyl-2 -pyrrolidone (NVP). Such a system is compared to IPN's based on a siloxane monomer - TRIS (3 - [tris (trimethylsiloxy) silyl] propyl methacrylate]), well known in the field of contact lens thanks to its properties of oxygen transport. These systems are chosen as a reference. In a second part, our research was concentrated on the development of IPN based on alginate and polyacrylamide which have demonstrated attractive properties for biomedical applications, especially their mechanical properties. Several formulations of biocompatible hydrogels were prepared and the influence of their composition on the interest properties is described. These hydrogels are characterized from a chemical point of view by FTIR spectroscopy and GC-MS chromatography, from themorphological point of view by SEM microscopy in order to prove the presence of co-continuous phases. The mechanicalproperties were also investigated. The differential scanning calorimetry (DSC) was used to determine and quantify theabsorbed water in its various thermodynamic states. The oxygen permeability was measured by polarographicelectrochemical method and relations between this parameter and gel swelling and structural properties discussed. Anotherpart of the project is computational simulation of hydrogel systems and its physico-chemical properties. Especially, wewere focused on modeling of various physic-chemical processes in hydrogels such as their swelling in water anddiffusion of gases molecules. We used molecular dynamics method (MD) with the COMPASS force field to be able tomodel polymer systems widely used in contact lens field.

L'orientation des lentilles sclérales devient extrêmement importante pour maximiser la stabilité et la vision chez des patients qui portent des lentilles ayant une face antérieure torique. Les techniques cliniques actuelles pour déterminer la rotation d'une lentille sclérale impliquent l'utilisation de lentilles diagnostiques; cependant, ces méthodes nécessitent beaucoup de temps de chaise pour obtenir un ajustement optimal. Des appareils novateurs existent maintenant pour évaluer la forme de la surface oculaire et peuvent s’avérer utiles pour prédire la rotation des lentilles sclérales et augmenter l'efficacité globale des ajustements. Le but de cette étude comparative et randomisée était d'évaluer la rotation des lentilles sclérales en se basant sur des valeurs fournies par deux topographes. Quinze participants ont été recrutés et leurs deux yeux ont été imagés à l'aide de deux topographes: le Eye Surface Profiler (ESP) et le Cornea Sclera Profile (CSP). Les participants ont ensuite été ajustés avec la lentille OneFit MED dans un oeil et la Zenlens dans l'autre. La rotation de chaque lentille a été évaluée à l’aide de la lampe à fente et comparée à l’axe le plus cambré de l’astigmatisme conjonctival identifié par chaque topographe. Bien que les rotations des deux instruments ne soient pas comparables, l'ESP a prédit une rotation à moins de 15° de l'observation à la lampe à fente, ce qui la rend cliniquement acceptable pour les lentilles avec de faibles valeurs de puissance cylindrique. L'acuité visuelle des patients portant des lentilles avec des quantités élevées de toricité pouvant être plus affectée par la quantité de rotation, les ajustements empiriques semblent, à ce stade, être déconseillés pour ces cas. / Scleral lens orientation becomes extremely important to maximize vision and lens stability in patients who are fitted in front-toric lenses. Current clinical techniques to determine the rotation of a scleral lens involve the use of diagnostic lenses; however, these methods require a substantial amount of chair time to achieve an optimal fit. Contemporary equipment exists to evaluate ocular surface shape, which could be useful in predicting scleral lens rotation and increasing the overall efficiency of scleral lens adjustments. The goal of this comparative and randomized study was to evaluate scleral lens rotation based on the values provided by two scleral topographers. Fifteen participants were recruited and both eyes were imaged using two scleral topographers: the Eye Surface Profiler (ESP) and the Cornea Sclera Profile (CSP). Participants were fitted with the OneFit MED on one eye and the Zenlens on the other. Each lens’s rotation was evaluated at the slit lamp and compared to the steep axis of conjunctival astigmatism identified by each topographer. While the rotations from both instruments are not comparable, the ESP predicted rotation within 15˚ from slit lamp observation, which makes it clinically acceptable for lenses with low values of cylindrical power. The visual acuity of patients wearing lenses with a high amount of toricity may be affected by the amount of rotation and are not suitable for empirical fittings at this point in time.

In this study, the zwitterionic monomer [2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA) was polymerized in a controlled manner by reversible addition-fragmentation chain transfer (RAFT) polymerization. The SBMA was also polymerized by atom transfer radical polymerization (ATRP) but in a less controlled manner why ATRP was discarded for further use in the study. The RAFT polymerized p(SBMA) was end-group modified through aminolysis forming a thiol end-group. The zwitterionic polymers have considerable anti-fouling properties and could be of use in contact lenses to prolong the wear-time. Model contact lens hydrogel substrates were synthesized, through free radical polymerization, consisting of 1/3 of silicone monomer, 2/3 of dimethyl acrylamide (DMA) and small percentages of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) cross-linker. These had poor mechanical strength and could only be used to explore the effect of surface chemical modification. The p(SBMA)-thiol was ‘graftedto’, by applying thiol-epoxide ring-opening, at a free radical polymerized co-polymer consisting of DMA and GMA indicating that this could work for the model hydrogel surfaces. / I denna studie polymeriserades den zwitterjoniska monomeren [2- (metakryloyloxi) etyl] dimetyl (3-sulfopropyl) ammoniumhydroxid (SBMA) på ett kontrollerat sätt genom ”reversible additionfragmentation chain transfer” (RAFT) polymerisation. SBMA polymeriserades också genom “atom transfer radical polymerization" (ATRP) men på ett mindre kontrollerat sätt varför ATRP då förkastades för vidare användning i arbetet. p(SBMA) blev ändgruppsmodifierad genom aminolys som då bildade en tiol ändgrupp. Zwitterjoniska polymerer kan vara bra för att förhindra tillväxt av biofilmer/beläggningar och kan därför bidra till att användningstiden för kontaktlinser kan förlängas. Modellytor baserade på hydrogel framställdes genom friradikalpolymerisation, med syfte att efterlikna en kontaktlins. Modellmaterialet består av 1/3 av silikoninnehållande monomer, 2/3 av dimetylakrylamid (DMA) och små mängder glycidylmetakrylat (GMA) samt etylenglykoldimetakrylat (EGDMA) som tvärbindare. Dessa modellytor hade dålig mekanisk hållfasthet och kunde endast användas för att utvärdera effekterna av ytmodifiering. Genom att använda tiol-epoxi ring-öppning utav p(SBMA)-tiol på en sam-polymer bestående av (DMA) och (GMA) indikerade detta att "ympning-till" skulle kunna fungera för hydrogels modellytorna.

<p>Glaucoma is the leading cause of irreversible blindness worldwide. While current therapies aim to lower elevated intraocular pressure (IOP) to prevent blindness, they often do not provide the desired long-term efficacy, can fail over time, and have systemic side effects. Electroceutical stimulation can be a solution to many of these current issues with glaucoma treatment, as it is believed to have fewer systemic side effects and quicker response times. The goal of this work is to develop and demonstrate a novel system using electrical stimulation to lower intraocular pressure. I present data from a human clinical study and an ongoing clinical trial of the IOPTx™ system, a wearable electroceutical for treating glaucoma, that provides preliminary evidence of efficacy and safety. <a>Furthermore, no current glaucoma treatments allow for closed-loop, continuous monitoring of IOP, requiring more frequent doctor visits or forcing patients and clinicians to operate in the dark. Using an electroceutical therapeutic device with closed-loop feedback and continuous IOP recording can improve glaucoma management. I combined a pressure sensor with this electroceutical therapy, implanted the sensor and stimulation coils in rabbits, and stimulated the eyes. However, to better understand the optimal stimulation parameters, long-term effects, and mechanisms of action, an integrated circuit is designed as part of a fully implantable, closed-loop device. The chip was fabricated in 0.18 </a>µm CMOS process and validated on the benchtop and <i>in vivo</i>. In the future, this electroceutical device has the potential to be a novel treatment for patients suffering from glaucoma.</p>

No description available.

This thesis designed and fabricated various devices that were interfaced to an IC for an active contact lens that notifies the user of an event by detection of an external wireless signal. The contact lens consisted of an embedded antenna providing communication with a 2.4GHz system, as well as inductive charging at an operating frequency of 13.56 MHz. The lens utilized a CBC005 5µAh thin film battery by Cymbet and a manufactured graphene super capacitor as a power source. The custom integrated circuit (IC) was designed using the On Semiconductor CMOS C5 0.6 µm process to manage the battery and drive the display. A transparent, flexible, single cell display was developed utilizing electrochromic ink to indicate to the user of an event. Assembly of the components, encapsulation, and molding were implemented to create the final product. The material properties of the chosen substrate were analyzed for their clearness, flexibility, and biocompatibility to determine its suitability as a contact lens material. Finally, the two different fabrication techniques (microfabrication and screen printing) that were employed to make the devices are compared to determine the favorable process for each part of the system.