Table 1.

Classes of expression vectors in gene therapy (GT)

NON-VIRAL VECTORS
We need to transfer am expression vector (commonly a plasmid) in recipient cells. We can use physical methods (in vivo electroporation, ultrasounds) or chemical methods. The aforementioned methods are secure, easy to perform and cost-effective. However, their delivery is less efficient than in viral vectors. After their introduction into the cells, non-viral vectors commonly persist in the cytoplasm. There, they will express the specific gene protein.
VIRAL VECTORS
They are adenoviruses, recombinant adeno-associated viral (rAAV), retroviruses, and baculoviruses. Currently, viral vectors are preferred with most research focusing on the use of recombinant adeno-associated viral vectors to deliver all types of genes for all types of cartilage pathology. Currently there are about 50 adenovirus serotypes available for GT. Serotype 5 (Ad5) is the mostly used in all kind of studies (in vitro and in vivo).