Gene delivery
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells.
[8] Non-viral gene delivery was first reported on in 1943 by Avery et al. who showed cellular phenotype change via exogenous DNA exposure.
[10] For some bacteria no external methods are need to introduce genes as they are naturally able to take up foreign DNA.
[5] Chemical vectors usually enter cells by endocytosis and can protect genetic material from degradation.
[6] One of the simplest method involves altering the environment of the cell and then stressing it by giving it a heat shock.
Typically the cells are incubated in a solution containing divalent cations (often calcium chloride) under cold conditions, before being exposed to a heat pulse.
Another simple methods involves using calcium phosphate to bind the DNA and then exposing it to cultured cells.
[14][15] Artificial gene delivery can be mediated by physical methods which uses force to introduce genetic material through the cell membrane.
[11] Sonoporation is the transient permeation of cell membranes assisted by ultrasound, typically in the presence of gas microbubbles.
[19][20] Photoporation is when laser pulses are used to create pores in a cell membrane to allow entry of genetic material.
[22] Plant tissue are cut into small pieces and soaked in a fluid containing suspended Agrobacterium.
The only essential parts of the T-DNA are its two small (25 base pair) border repeats, at least one of which is needed for plant transformation.
Viral methods of gene delivery are more likely to induce an immune response, but they have high efficiency.
Viruses can only deliver very small pieces of DNA into the cells, it is labor-intensive and there are risks of random insertion sites, cytopathic effects and mutagenesis.
[2] Viruses are efficient at delivering genetic material to the host cell's nucleus, which is vital for replication.
Gene delivery in therapeutic settings utilizes non-immunogenic vectors capable of cell specificity that can deliver an adequate amount of transgene expression to cause the desired effect.
