Particie bombardment or biolistic or gene gun is the most important and effective diret gene transfer method in regular use. In general it is a way of transfecting cells. Suppose you want to deliver a gene or plasmid into the diffrent cell and this particular cell culture is difficult to transfect using another method. This method was invented by John C. Sanford, Ed Wolf, and Nelson Allen.
How does the gene gun works?
In this method you have a nanoparticles (gold or tungsten), which are coated by a desired gene or plasmid.
Now you have a equipment capable of accelerating these coated particles just like a gun.
In this gun Helium gas fuels the chamber and pressure propels micro carrier with modified nanoparticles into the stopping screen.
When the micro carrier hits it, DNA coated nanoparticles propelled through the screen and into the target cell in petridish.
You can actually shoot DNA coated gold particals any cells without damaging most of these cells. It depend on both nanoparticles size and the impulse. Once with the diameter of about 1micrometer had initially been used but relatively recent study had revealed two orders of magnitude. Smaller nanoparticles are also suitable.
For long period of time tungsten or gold nanoparticles
1micrometer in diameter were widely used by researchers. Insted of gold and tungsten silica nanoparticles are much better due to their biodegradability and non toxicity.
Applications of Gene gun Technique
1) To study of neuronal dendritic branching and dendritic spine morphology- special dye is used as a molecule to deliver into the cell.2) Plant transformation- reported gene is used to find out whether it's successful or not.
3) Transfection of neurons- some of which are notoriously difficult to transfect.
4)Transfection of cells deep in tissue.
5)DNA vaccination for inducing protective immunity to infection and malignancy.
Weaknesses of Gene gun method
1) Perticular nanoparticle may contain molecule to deliver or may not.
2) Each particular nanoparticles contain different quantity of that molecule on its surface.
3) Low efficiency of the metal nanoparticles in reaching the entire tissue due to the low penetration of the particles.
4) Surgery is often necessary to use the technique in order to reach any non superficial tissue.
