Nanomedicine-Based Gene Delivery for the Retina and Posterior Segment Diseases
The eye is an immune-privileged site and is more amenable to genetic therapy. A number of diseases in the posterior segment of the eye have genetic origin. The posterior segment of the eye is difficult to access. But routes to deliver drugs and genes have been worked upon. The genetic therapy ensures long-term treatment of the disease in the eye. The genes that are to be delivered to their proper site can be given through viral and non-viral vectors. Viral vectors offer a number of advantages when it comes to transfection efficiency and gene expression but are associated with immunity issues and cannot be loaded with genes which are more than 5 kb. Over the years non-viral gene vectors are becoming increasingly popular because of their higher gene loading capacity and number of distinct advantages over the viral vectors. But the genes that are to be delivered to the nucleus have to escape a number of degradative mechanisms outside and inside the cell to reach the nucleus. Lipoplexes and polyplexes have been successfully used in the treatment in nonclinical studies, but the clinical applications have still to see the light of the day.