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Toward rational design of gene carriers: a novel ex vivo model to study the vitreoretinal interface as a barrier
Author(s) -
Peynshaert K.,
Fradot V.,
Picaud S.,
De Smedt S.,
Remaut K.
Publication year - 2016
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2016.0376
Subject(s) - retina , retinal , penetration (warfare) , ex vivo , biophysics , nanoparticle , inner limiting membrane , materials science , chemistry , nanotechnology , in vitro , biology , optics , physics , biochemistry , operations research , engineering
Purpose The vitreoretinal interface poses a serious hurdle for the retinal delivery of viral and non‐viral gene vectors after intravitreal injection. We have therefore developed a retinal model especially designed to study to which extent the ILM is a barrier for the penetration of vectors into the retina. In contrast to all existing explant models, ours is bovine‐derived and more importantly, the vitreous remains attached to the retina at all times to guarantee an intact vitreoretinal interface. Methods To investigate the influence of nanoparticle physicochemistry on their ability to penetrate the ILM we have injected various carboxylated polystyrene particles with a size range between 20 and 200 nm intravitreally in our model. After diffusion overnight the Müller cells are stained with Mitotracker Deep red and the nuclei with Hoechst. Finally, a z‐stack of confocal images of the retina is recorded using a water dipping objective that is brought into contact with the vitreous layer on top of the retina. Results Our data clearly illustrated that the ILM significantly hinders particle penetration into the retina. We also found that this penetration is greatly size‐dependent: the cut‐off for nanoparticles to cross the ILM lies between 40 and 100 nm. Intriguingly, the particles that did cross the ILM co‐localized solely with Müller cells, indicating these cells actively capture the nanoparticles out of the ILM and shuttle them into the retina. Conclusions In conclusion, we developed a model set‐up greatly mimicking human physiology to investigate the influence of particle physicochemistry on their ability to cross the ILM after intravitreal injection. This data collection will signify a leap forward in the rational design of gene vectors with the retina as their target, since this way their design can be tuned to actual in vivo requirements.