Fig. 2.

In- vivo and ex- vivo strategies of gene therapy. In- vivo and ex- vivo gene transfer strategies are shown. For in- vivo gene transfer, genetic materials containing therapeutic genes, such as viral vectors, nanoparticles, and ribosomes, are delivered directly to the patient, and genetic modification occurs in situ. For ex- vivo gene transfer, the harvested cells are modified by the appropriate gene delivery tools in vitro (e.g., recombinant viruses genome editing technologies). The modified cells are then delivered back to the patient via autologous or allogeneic transplantation after the evaluation of off-target effects.