Figure 1.

Gene transfer technologies applied in tissue repair. In the case of in vitro gene transfer target cells are isolated from a small biopsy and cultured. Once a sufficient cell number is obtained, cells are incubated with the viral or non-viral vector containing the therapeutic gene of interest; cells can be selected to ensure a high number of transfected cells; transgenic cells can be incorporated in biodegradable matrix (biological, synthetic); genetically engineered grafts can then be transplanted to the donor. In contrast, for the in vivo gene transfer approach plasmid DNA or virus, with or without a delivery vehicle, is injected directly into the desired organ.