Biotechnology—Principles and Processes — BIOLOGY STD 12 Science — Question

In genetic engineering, a gene gun or biolistic particle delivery system is a device used to deliver foreign DNA. By coating particles of a heavy metal with a gene of interest and firing these micro-projectiles into cells using mechanical force, an integration of desired genetic information can be introduced into desired cells. The technique involved with such micro-projectile delivery of DNA is also known as biolistics.
This device is able to transform almost any type of cell and is not limited to the transformation of the nucleus; it can also transform organelles, including plastids and mitochondria.
The earliest custom manufactured gene guns used a 22 caliber nail gun cartridge to propel a polyethylene cylinder (bullet) down a 22 caliber douglas barrel. A droplet of the tungsten powder coated with genetic material was placed onto the bullet and shot down into a petri dish below. The bullet welded to the disk below the Petri plate, and the genetic material blasted into the sample with a doughnut effect involving devastation in the middle of the sample with a ring of good transformation around the periphery. The gun was connected to a vaccum pump. Other heavy metals such as gold and silver are also used to deliver genetic material with gold being favoured due to lower cytotoxicity in comparison to tungsten projectile carriers.
Gene guns are mostly used with plant cells. However, there is much potential use in humans and other animals as well.