High-velocity microprojectiles are also used to deliver DNA into the plant cells. After being accelerated, small tungsten or gold particles (microprojectiles) pierce cell walls and membranes and enter intact plant cells without killing them. These microprojectiles are fired at the cells from a particle gun. The disarmed pathogen vectors then infect the cell and the recombinant DNA molecules are transferred. This technique is termed as biolistics or gene gun.