Diseases can be treated using viruses as vector to deliver genes in Gene Therapy. Viruses as gene vector, however, can themselves cause problems in that they may initiate inflammation and the genes may be expressed at too high a level or for too long period of exposure. The goal of Nano Technology in gene therapy is delivery of therapeutic genes without a virus, using nanoparticles as non-viral vector to deliver the genes. The particles can be made with multiple layers so the outer layer with covering of peptide that can target the particles to cells of interest at specific site. The emergent Nanotechnology in gene therapy is used to develop unique approaches in treating the retinopathies and the development of micro and Nano dimensional artificial antigen presenting cells for cancer immunotherapy. These antigen presenting cells mimic the natural signals in immunity that killer T-cells receive when there is an invader (bacteria, virus, cancer cell, etc.) in the body.