Although there are …show more content…
Being that RNA is single stranded and very unstable, even though RNA vectors are used, mostly DNA non-viral vectors are preferred for their stability. These vectors tend to have barriers associated with the cell membranes of the target cells due to the charge difference associated with the membrane potential; this is considered the most critical limiting step of nucleic acid transfection (2). In addition, there are nucleases that exist in blood and other bodily fluids that can degrade unprotected non-viral vectors and prevent them from reaching the target cell. Nucleic acids typically enter cells through physical uptake mechanisms like endocytosis, phagocytosis, or pinocytosis …show more content…
They are primarily comprised of nucleic acid enclosed in a protein coat called a capsid that serves to provide protection for the genetic material. Unlike non-viral vectors, viral vectors are more likely to trigger a host immune response upon transfection of the DNA. Although there has been some success with non-viral vectors in gene therapy, these successes have been limited. Viruses have evolved to become very efficient at delivering nucleic acid to several cells types (5). The major hurdle to be overcome when considering the usage of a virus as a vector, is eliminating its pathogenicity. In order to turn a virus into a vector, the virus is genetically engineered to decrease or completely remove pathogenicity and its genome is replaced with the therapeutic gene. The viral vectors that are being utilized currently in gene therapy are, Adenoviral vectors, Retroviral vectors, Adeno-associated viral vectors (AAV), Herpes Simplex viral (HSV) vectors and lentiviral