Extraocular delivery of bioswitchable tri-miR-22-loaded tetrahedral DNA nanostructures for intraocular neovascular and neurodegenerative repair

Ocular neovascular and neurodegenerative diseases, such as diabetic retinopathy and age-related macular degeneration, are characterized by abnormal angiogenesis, vascular leakage, and progressive retinal neurodegeneration, ultimately leading to irreversible vision loss. Here, we present a tetrahedral framework DNA-based bioswitchable Tri-miR-22 mimic delivery system (BiRDS), which is specifically engineered for extraocular administration. In vitro, BiRDS can penetrate the cell membrane within 24 h and accumulate extensively in the cytoplasm. Through transscleral-choroidal-retinal penetration, BiRDS achieves robust delivery to the choroid and retina within 18 h without the need for intravitreal injection in mice. The BiRDS can effectively inhibit the proliferation, tube formation and migration abilities of human umbilical vein endothelial cells. In murine models of choroidal neovascularization and oxygen-induced retinopathy, BiRDS not only suppresses retinal pathological neovascularization with efficacy comparable to that of current anti-VEGF agents, but also possesses unique effects that current agents lack, such as improved retinal perfusion and preserved neuronal integrity, thereby contributing to the protection of visual function. Furthermore, transcriptomic profiling and molecular validation revealed that BiRDS exerts its therapeutic efficacy by inhibiting the Wnt/β-catenin pathway, a key driver of mediating the aforementioned pathological processes. This study highlights BiRDS as a next-generation RNA nanotherapy with broad clinical potential, offering site specific, multitargeted modulation via a minimally invasive and patient-friendly route.