Abstract
Posterior capsule opacification (PCO) is the most common complication arising from the corrective surgery used to treat cataract patients. Ti3C2Tx (MXene) has been applied as a transparent conductive electrode (TCE) in an adjustable focus lens model to provide changes in dioptric range for an accommodative IOL (AIOL) design. However, its impact on the wound-healing response of lens epithelial cells (LEC) contributing to PCO development is not yet known. This thesis investigates the effects of Ti3C2Tx on the initial wound healing response and epithelial-mesenchymal transition (EMT) pathway of residual LEC, which occurs post cataract surgery (PCS) and contributes to PCO development.Ti3C2Tx was synthesised using the MILD method and processed to achieve uniform flake size and dispersed solutions across batches as confirmed by dynamic light scattering and scanning electron microscopy. Contact angle measurements confirmed the hydrophilic nature of Ti3C2Tx by increasing the wettability of hydrophobic IOLs coated with Ti3C2Tx. ELISA analysis showed that LECs grown on Ti3C2Tx coatings showed no significant upregulation of the pro-inflammatory cytokines IL-1β and IL-6. Cells treated with Ti3C2Tx and IL-1β showed a significant suppression of both the gene and protein expression of IL-1β and markedly reduced the expression of IL-6 gene and protein and the CXCL1 gene relative to cells treated with IL-1β alone, as quantified by q-PCR. RNA sequencing showed that Ti3C2Tx coatings did not upregulate any hallmark inflammatory gene sets. Whilst no significant broad downregulation of pro-inflammatory gene sets was observed at the concentration of Ti3C2Tx used, a marked reduction in the cytokine-cytokine receptor interaction pathways and secretion of pro-inflammatory cytokines occurred. Moreover, immunocytochemistry, scratch assay and western blot analysis showed that Ti3C2Tx did not promote EMT pathways and repressed overexpression of migratory markers whilst increasing wound closure rate thereby promoting a positive resolution of LEC wound healing response. A potential mechanism was suggested that Ti3C2Tx interacts with the cytokine-cytokine receptor interaction pathway, promoting anti-inflammatory mechanisms to resolve the inflammation and EMT response in LECs. Ti3C2Tx did not upregulate key senescence markers in FHL124 cells as shown by 5-ethynyl-2′-deoxyuridine (EdU) and p21 and p16 expression quantified by q-PCR. This work has shown for the first time that a silicone-based capsule bag model can be used to mimic in part the properties of the capsule bag for initial assessment of IOL materials in a 3-dimensional (3D) model prior to the use of invasive animal or human tissue derived capsule bag models. In conclusion, this body of work has demonstrated the ability of Ti3C2Tx to promote positive resolution of the LEC wound healing response by suppressing hyperinflammation and EMT pathways contributing to PCO development.
| Date of Award | Mar 2023 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Susan Sandeman (Supervisor), Marcus Dymond (Supervisor), Joseph Lacey (Supervisor) & Yury Gogotsi (Supervisor) |