Since 1990, dozens of biotech and gene therapy companies have hired life scientists and launched research programs to find safe, effective carriers to shuttle therapeutic genes into the body. In the vast majority, therapeutic genes are packed into disarmed viruses, which shuttle the genetic payload into a cell's chromosomes. These viral vectors require the expertise of virologists, biochemists, and molecular biologists, among others. This is where work needs to be done. But these vectors typically infect only dividing cells, which limits their use.
Adenoviral vectors are efficient.
However, they alert a host's immune cells, which sometimes can render repeat administrations fruitless. They also can be toxic. Synthetic vectors generally are considered safe. But these must be created from scratch, and scientists are still learning about their efficiency. The successful application of gene transfer to gene therapy .