Electroporation: high frequency of occurrence of a transient high-permeability state in erythrocytes and intact yeast.

We present the first determinations of population distributions of macromolecule uptake due to electroporation, the percentage of cells which participate and, for the yeast, the subpopulation of cells whose membranes exhibit significant recovery following macromolecule uptake. Flow cytometry is used to measure the uptake of a first test molecule (green fluorescence, FITC-dextran; 70 kDa) and also, for the yeast, the subsequent uptake of a second, much smaller, test molecule (red fluorescence, propidium iodide; 660 Da), which provides a measure of membrane recovery. A dramatic 20% (erythrocytes) to 75% (intact Schizosaccharomyces pombe) of cells can take up the first test molecule within 5 min of a pulse.