Nanotechnology for Gene Delivery to the Eye

The relatively immune-privileged status of the eye makes it an interesting target for gene delivery. Gene delivery to the eye using viral vectors via subretinal and intravitreal injections has been extensively investigated. Recently, the safety of recombinant adeno-associated virus vector expressing RPE65 complementary DNA (cDNA) in a limited clinical trial of three patients has also been reported. Nanotechnology-based non-viral vectors offer the advantages of safety and flexibility in terms of loading capacity and delivery system design compared with viral vectors. An ideal non-viral vector should be non-toxic, efficiently taken up into the target cells and conducive to gene expression, and should protect the gene against enzymatic degradation. Multiple kinds of nanotechnology-based non-viral vectors have been investigated for potential applications for gene delivery to the eye, namely nanoplexes, dendrimers, micelles, nanoparticles and liposomes. This article summarises and discusses key advances in the application of nanotechnology for gene delivery to the eye.