Gene therapy can cure the root causes and eradicate the diseases that people have been unable to do in the past, which has naturally attracted extensive attention all over the world. The core problem of gene therapy is how to send the target gene to the right place. At present, there are three methods to transport the target gene into human cells: physical method, chemical method and biological method.
In physical methods, the target gene can be injected into the target cell with a special syringe, or the target gene can be sent into the target cell with a special gene gun in bombardment. In addition, electroporation can also be used to send the target gene into the target cell.
In chemical methods, it is often necessary to find an intermediate chemical substance, which can not only combine with genes, but also fuse with cells. Therefore, we first combine the target gene with chemicals, and then contact the combination with the target cell, and the target gene can be transferred to the target cell.
For example, there is an artificial capsule liposome composed of spherical phospholipid bilayer membrane, which can either wrap the target gene in the capsule or bind to the surface of the capsule membrane. When this liposome is combined with the target cell, the liposome can fuse with each other's cell membrane and send the target gene into the target cell. In addition to lipids, diethylaminoethyl glucan can also play an important role in transporting target genes.
Biological method is now the most widely used method, which is used in the gene therapy of the first genetic disease in the world. In biological methods, we need to rely on a harmless transportation tool to transport the target gene, and this safer and reliable tool is usually a virus, such as adenovirus.
If the target gene is compared to a person, whether by plane or train, people have to get on the means of transportation first and feel safe and comfortable. In this way, the target gene can be safely and comfortably put on the transport vehicle of adenovirus. In medicine, this carrying process is called integration, and the process of sending the target gene into the target cell with adenovirus is called infection.
Adenovirus will never make trouble when transporting the target gene. It will neither wake up the sleeping oncogene nor inactivate the active tumor suppressor gene. However, although the delivery of the target gene through adenovirus is safe and reliable, the adenovirus DNA loaded with the target gene is free in the nucleus and is not inserted into the cell chromosome. Therefore, the target gene may not be expressed for a long time, making it difficult to maintain the effect of gene therapy for a long time.