Abstract: A device for the rapid injection of a biological into the skin of a person. The device comprisies a hand-held applicator and a tape cassette adapted to be inserted into the applicator prior to use. The cassette houses a transportable tape having multiple doses of a biological disposed on a plurality of discrete clusters of microneedles affixed to the tape. In operation, a cassette is inserted into the applicator and a discrete cluster of microneedles advanced to a position adjacent a delivery opening in the applicator. A trigger advances the microneedle cluster to project outwardly through the delivery opening. The applicator is then pressed against the skin to force the cluster of microneedles into the skin. The applicator further includes means for applying an electric field between the microneedles and the skin to electrophoretically assist penetation of the biological into the skin.