We describe a method and apparatus designed to rapidly and reproducibly produce transient, survivable plasma membrane disruptions--"wounds"--in order to gain access to the cytoplasm of eukaryotic cells growing in culture. Compressed gas is used to propel glass beads, dispersed as a uniform aerosol, at adherent cells growing on a culture substratum. The impact of beads with the cells creates plasma membrane wounds. Macromolecules, such as dyes, proteins and plasmid DNAs, diffuse from the extracellular environment directly into the cytoplasmic compartment of the cell through these wounds. Resealing of the plasma membrane, necessary for cell survival, traps macromolecules within the cytoplasm of the cell.