Measuring The Intravitreal Mobility of Nanomedicines with Single-Particle Tracking Microscopy

Abstract

An ex vivo eye model is presented for studying nanoparticle mobility in intact vitreous humor by single-particle tracking microscopy. These results give important guidelines for developing gene- and drug-delivery nanomedicines that are compatible with intravitreal administration.

Lysosomal capturing of cytoplasmic injected nanoparticles by autophagy: An additional barrier to non viral gene delivery

“…With electroporation, however, an autophagy response was not noted (17). Also previously, we suggested that autophagy could be responsible for the long term endosomal entrapment of nanoparticles in Retinal Pigment Epithelial (RPE) cells (18). In the current paper, we demonstrate the occurrence of autophagy on inert polystyrene beads and plasmid DNA containing poly-ethylene-imine (PEI) nanoparticles, that were directly introduced in the cytoplasm of the cells by microinjection (Fig 1, 10).…”

“…Labeling principles are described (22). Correlative microscopy of fluorescence-and immunogold-labeled ultrathin cryosections was done essentially as described (23) For a more detailed description of both the SPT microscope and the trajectory analysis, the reader is referred to (18). For confocal images, colocalization analysis of red fluorescent nanoparticles with the green labeled cellular compartments were performed in Image J, using two different colocalization plugins (colocalization and the JACOp plugin) (25) (http://rsbweb.nih.gov/ij/).…”

Coating nanocarriers with hyaluronic acid facilitates intravitreal drug delivery for retinal gene therapy

“…Indeed, we have previously shown that the vitreous humour poses a barrier to nanocarriers for retinal gene delivery [9,10].…”

“…Recently we reported on an ex vivo assay for measuring the mobility of fluorescent nanoparticles in intact vitreous humour on a single-particle level [9]. By removing the anterior parts (cornea, iris, and lens) of excised bovine eyes, an optical window was formed allowing us to use high-resolution fluorescence microscopy without damaging the fragile structure of the vitreous humour.…”

“…Therefore, intraocular administration routes which bypass these ocular barriers are frequently employed (Figure 1). While clinical success has been achieved primarily by subretinal injection of nanoparticles, this procedure is known to be very invasive, potentially associated with serious adverse effects and not feasible on a large scale [9]. Therefore, intravitreal injection represents an attractive alternative route of A C C E P T E D M A N U S C R I P T…”