Use of Gene Guns

Question

Gene guns (biolistic particle delivery systems) use gold or tungsten atoms coated with plasmid DNA and bombard it on cells. Their use, as far as I understand, is mostly limited to plant cells. From what I found out, this seems to be due to the difficulty of passing vectors through the rigid cell wall that a plant cell has. Is this really the sole reason why gene guns are mostly used for plant hosts? Fungi also possess a chitin cell wall - is the gene gun used for fungi hosts as well?

Answer 1

I think one of the orginal reasons for using biolistic on plant cells was that it seemed to be the only method which proved to be effective. This is due to some reasons:

• A wide range of highly successful methodes for prokaryotic cells (calcium chlorid method, electroporation)
• The plant cell has in comparison to animal cells a additional layer (= cell wall) that consists mainly of cellulose chains, which are stabilized by interchain hydrogen bonds to form a crystalline lattice structure (= microfibril), and thus offering the cell high mechanical defense. (book: "Plant Biochemistry", P. 4) This layer mostly needs to be removed before using other methodes than the gene gun, because it can hardly be penetrated. (chemgapedia.de on "Mikroinjektion")
• The high inner cell pressure (~3 MPa) of the plant cell, which makes microinjection hard to accomplish: When the cell wall is perforated with a cannula the pressure within the cell drops dramatically resulting in cell death (chemgapedia.de on "Mikroinjektion"). I am not quite sure why the same thing isnt happening when its pierced by the gene "bullet", but I think its because of higher speed and a smaller penetration radius.
• Plant cells are big (up to 0,1 mm) and packed up closly and thus an easy target (sparknotes.com on "cell differences")

When it comes to fungi cells, I don't see a reason why they shouldn't be using biolistic on them as well (besides for yeast cells, they might be to small).

The gene gun is the only way to inject even cell organelles, like mitochondria and chloroplasts, into cells. So its already huge area of application will definitly grow in the future. (wikipedia.org on "transfection")