Enzyme-Functionalized Microparticles to Open the Vitreoretinal Interface

The transport of therapeutics to their site of action is often hindered by biological barriers, such as cell layers and basement membranes. Among these, the inner limiting membrane (ILM) represents a major barrier within the eye, separating the vitreous body from the retina and restricting the penetration of intravitreally administered materials. Due to its dense, cross-linked composition, only the smallest nanoparticles can pass through the ILM. Here, we demonstrate that active microcolloids decorated with enzymes can locally open the ILM and thereby facilitate the diffusion of passive carriers into retinal tissue. We utilize an ex-vivo porcine eye model to determine the membrane permeability threshold using fluorescent nanoprobes. We further show that collagenase-decorated silica microparticles can facilitate the transport of nanoparticles, while exhibiting excellent biocompatibility with no adverse morphological or functional retinal effects over a six-week in vivo evaluation in a porcine model. Overall, our findings introduce a biocompatible and minimally invasive strategy to facilitate the targeted nanoparticle transport across biological barriers with promising implications for gene therapy.