Intravitreal injection of silicate nanoparticles has been safely used for management of choroidal neovascularization. This study investigates transmission of topical silicate nanoparticles (SiNps) as a non-invasive route through the corneal stroma, anterior chamber, and vitreous fluids by scanning electron microscope (SEM) and inductivity coupled plasma (ICP), respectively.

Thirty and 80 nm sizes of SiNps determined by dynamic light scattering (DLS) were used in this study. The permeability of SiNps was examined across isolated corneal buttons over a 30-minuteperiod. To visualize the transport and diffusion of nanoparticles through the corneal tissue, SiNps were applied over the corneal surface and evaluated at 30 min after SiNps loading by SEM after performing the transport across the corneal tissues, the part of the tissue exposed to the nanoparticle suspension was cut off in an optimal cutting temperature (OCT) medium for frozen section. Ten-µm-thick sections were cut and visualized using SEM. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) was employed to determine the concentration of the SiNP suspension.

The determined range of synthesized SiNps by DLS was 30-80 nm. Transmission of SiNps (30 and 80 nm) through the corneal stroma was shown successfully with electron microscopy images. The ICP results revealed SiNps in anterior chamber and vitreous fluid.

Topical administration of SiNps, as a non-invasive, inexpensive, and available modality with acceptable penetration through the corneal stroma and deep to the intraocular fluids including anterior chamber and vitreous fluid, may be a suitable alternative for invasive intravitreal injection of other expensive anti-VEGF agents.