The aims of this research were to investigate polymer fibre morphology, overall mat morphology, mechanical properties and general handling of the mats, and ideal mat thickness in order to fabricate a suitable substrate for potential use in cell transplantation for application as a permanent substrate for the treatment of dry age-related macular degeneration (AMD). Polystyrene (PS), poly(ethylene terephthalate) (PET) and polyurethane (PU) were electrospun to ascertain the ideal electrospinning parameters to reproducibly obtain fibres to construct a mat as a potential candidate for a replacement Bruch’s membrane (BM). After identifying the ideal spinning parameters, mats were fabricated, their fibre morphology, overall mat morphology, and handling during processing were examined. This allowed the shortlisting of PS and PET substrates, which were suitable to be taken forward for further testing and cell culture. PU was found to be unsuitable as it had a tendency to become entwined and stick to itself, which would destroy the gross mat morphology. Therefore PU was excluded from further testing. Further handling, both quantitative and qualitative, and thickness and porosity were tested for PS and PET mats. Electrospun PET demonstrated greater handling and durability properties compared to PS mats, which were more fragile. PET was able to withstand twisting, folding, and rolling, whereas PS could not undergo twisting and fell apart. PS mats were thicker and more porous compared to PET mats, which was attributed to the widely spaced placement of the larger PS fibres and the fluffy gross morphology of the PS mats, in comparison to the closer fibre placement of the smaller PET mats which had a smooth gross mat morphology. Considering this, PS mats were compressed and thickness and porosity was reduced, while maintaining its fibrous structure. However the compressed PS mats became extremely fragile and could not withstand much handling. Although PET mats were thinner than PS mats, it did not match the native BM thickness and so experiments in varying collection time during electrospinning to match the native BM thickness were undertaken. Tensile tests, thickness and porosity measurements showed that PET tensile properties, thickness, and porosity reduced with reduced collection time. For the purposes of surface treatment and cell culture, uncompressed mats collected for 60 minutes were used since sufficient PS fibres were able to be collected to form a mat that was able to withstand processing at this collection time. Effect of UV/ozone surface treatment was tested for both PS and PET mats. Treatment of both substrate types affected protein adsorption, with evidence of aminolysis observed on PET substrates. Short-term initial growth and survival of retinal pigment epithelial cells (RPE cells) on electrospun, surface oxidised PS and PET was investigated. Untreated PS did not support cell proliferation and although treated PS did, the resultant RPE cell morphology was undesirable, therefore was not taken forward to long term cell culture. Treated and untreated PET supported cell proliferation, and was taken forward to the long term culture study, where cells exhibited the desired monolayer morphology. In this work it has been demonstrated that electrospun PET may potentially be a suitable candidate as cell carrier substrate for subsequent implantation in application towards AMD treatment.

Until recently, all in vitro drug susceptibility assays of cytomegalovirus (CMV) were performed in clinically irrelevant fibroblast cells. This study sought to test if drug susceptibility was affected by cell type. MRC-5 embryonic lung fibroblasts and ARPE-19 retinal pigmented epithelial cells were infected with BADrUL131-Y4 epithelial/fibroblast tropic virus under serial concentrations of ganciclovir (GCV) or maribavir (MBV). Virus was quantified using plaque reduction, GFP fluorescence, and yield reduction. Both drugs performed less efficiently in ARPE-19 cells. A cell type effect was observed for both plaque reduction and yield reduction assays with implications for the treatment of CMV retinitis as well as other manifestations of CMV Disease that involve non-fibroblast cell types.

Despite of all the research going on for the treatment of ocular diseases, age-related macular degeneration (AMD) remains one of the serious vision threatening disease worldwide. Choroidal neovascularization, a pathophysiological characteristic of wet AMD, is the growth of anomalous blood vessels in the eye choroidal layer. Neovascularization is a key factor in AMD and thus anti-angiogenic therapy is beneficial in reducing the development of new abnormal blood vessels to prevent progression of AMD. Axitinib, multi-receptor tyrosine kinase inhibitor, is a small molecule that works by blocking vascular endothelial growth factor receptors (VEGFR) and platelet derived growth factor receptors (PDGFR) responsible for developing neovascularization. Thus, goal of this study was to develop and characterise a sustained release formulation of Axitinib loaded poly (lactic-co-glycolic) acid (PLGA) nanoparticles. The nanoparticles were characterized for particle size and zeta potential as well as using DSC, TEM and in vitro drug release profile. The cytotoxicity of the formulation was evaluated on human retinal pigmented epithelium ARPE19 cells by MTT assay. The cellular uptake, anti-migration assay, and VEGF expression levels were found out in vitro using cells. The optimized formulation was 131.33 ± 31.20 nm in size with -4.63± 0.76 mV zeta potential. Entrapment efficiency was found to be 87.9 ± 2.7%. The cytotoxicity of ARPE19 cells was less than 12% for nanoparticles suggesting the in vitro compatibility at 10 µM concentration of drug. Cellular uptake, anti-migration assay and VEGF expression levels for the nanoparticles had greater uptake, had significant anti-angiogenic potential and exhibited inhibition of VEGF activity. The results showed successful development of axitinib loaded PLGA nanoparticles as an alternative potential treatment option for AMD.

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