High-velocity microprojectiles for delivering nucleic acids into living cells. 1987.

A method is described in which DNA or RNA is delivered into plant cells using small tungsten particles (microprojectiles; 4 µm diameter) at high velocity. After acceleration, the particles pierce the cell walls and membranes and enter the intact cells without killing them. Using this method, 1 cm² sections of Allium cepa epidermis were bombarded with tungsten particles coated with plasmid p35S-CAT, containing a gene that encodes chloramphenicol acetyltransferase (CAT). Extracts subsequently obtained from the tissue revealed expression of the gene, in the form of very high levels of CAT activity; controls showed negligible activity. It is suggested that the method can be used to study the transient expression of foreign genes in intact tissue and can possibly provide a broadly applicable means of transformation capable of circumventing the host range restrictions of Agrobacterium tumefaciens and the regeneration problems associated with protoplasts