Investigation of the effects of silica mesoporous drug carriers on reti̇nal pigment epithelial cells subjected to oxidative stress

Age-Related Macular Degeneration (AMD) is one of the leading causes of irreversible vision loss in developed countries. Oxidative stress, which accumulates in retinal pigment epithelial (RPE) cells, is known to play a key role in the pathogenesis of the disease. Oxidative stress damages cellular structures through the accumulation of reactive oxygen species (ROS), leading to cell death. In this study, oxidative stress was induced in ARPE-19 cells, an in vitro model of AMD, and the protective and therapeutic potential of silica-based mesoporous SBA-15 nanocarriers was investigated. SBA-15 was synthesized, and its morphological/structural characterization was performed using TEM, SEM, BET, and BJH analyses. Surface modification was carried out using trimethoxy[3 (methylamino) propyl]silane, [3-(N, N-dimethylamino) propyl] trimethoxysilane, and 3 aminopropyltrimethoxysilane to functionalize the material with amine groups. The functional groups were confirmed by FTIR analysis. Subsequently, the natural flavonoid Quercetin, known for its antioxidant properties, was loaded onto the nanocarriers, and the loading was verified via FTIR and UV Vis spectroscopy. The cytotoxic effects of pure SBA-15 and amine-modified SBA-15 structures were evaluated using ARPE-19 cell lines. Findings revealed that pure SBA-15 showed no toxicity, while amine functionalized SBA-15 induced a certain level of cytotoxicity. To establish an oxidative stress model, cells were treated with increasing doses of H₂O₂, and 300 µM H₂O₂ was determined as the optimal stress concentration. In cells exposed to oxidative stress, both pure SBA-15 and amine-modified SBA-15 significantly increased cell viability and reduced oxidative stress. Upon 24-hour incubation with Quercetin-loaded SBA-15, particularly pure SBA-15 and tertiary amine-modified SBA-15, oxidative stress was alleviated, promoting cellular recovery. The results of this study provide the first comprehensive data in the literature on the use of SBA 15-based materials as drug delivery systems in ARPE-19 cells and their effects on reducing oxidative stress. The findings are particularly significant as the synergistic protective effect of Quercetin-loaded SBA-15 with tertiary amine modification has not been previously reported. However, these preliminary results need to be supported by mechanistic studies and in vivo experiments to evaluate their potential for clinical applications.