Abstract
Purpose::
To develop efficient nonviral nano-vectors using biocompatible human serum albumin for retinal gene delivery.
Methods::
Human serum albumin nanoparticles (HSA NP) encapsulating a plasmid encoding Cu, Zn superoxide dismutase (SOD1) and enhanced yellow fluorescence protein (EYFP) were prepared using a desolvation-crosslinking method. The nuclease and vitreous humor stability of HAS NP encapsulated plasmid, in vitro plasmid release, intracellular trafficking, and in vitro and in vivo transfection were assessed.
Results::
Plasmid-encapsulated HSA NP prepared with desolvation-crosslinking method had a mean size of ~120 nm, zeta potential of -44 mV, and a plasmid encapsulation efficiency of 84%. HSA NP sustained the in vitro release of plasmid for up to 6 days, and protected the plasmid DNA against degradation by DNase I and vitreous humor. HSA NP were not cytotoxic to retinal pigment epithelial cells (ARPE 19) even at particle concentrations as high as 5 mg/ml and durations of exposures as long as 96 h. HSA NP were internalized by ARPE 19 cells primarily via caveolae pathway and secondly via clathrin pathway. Confocal image analysis indicated rapid endo-lysosomal escape of the nanoparticles. In vitro transfection efficiencies as high as 86% were achieved with HSA NP, which was 5-fold higher than Lipofectamine. HSA NP-transfected cells showed enhanced SOD1 activity that is 5-fold higher than untreated cells, indicating the delivery and expression of the functional gene. Intravitreal injection of HSA NP to the mouse eye at 130 ng dose of plasmid resulted in retinal expression of the reporter gene, compared to no expression in control animals. Thus, HAS NP is a useful vector for retinal gene delivery.
Conclusions::
HSA NP protect plasmid DNA, sustain DNA release, escape endo-lysosomes, and provide high transfection efficiency. HSA NP is a promising non-viral vector for gene delivery.
Keywords: retina • gene/expression • age-related macular degeneration