"Ultramicroinjection" of macromolecules or small particles into animal cells. A new technique based on virus-induced cell fusion.

A new method is described for the introduction of macromolecules and small particles into animal cells. The first step in this procedure is the trapping of particles in ghosts of human erythrocytes. This is achieved by the gradual hemolysis of erythrocytes in the presence of the particles to be trapped. The second step is the Sendai virus-induced fusion of the ghosts containing the particles with cells. By this method, ferritin and latex spheres (diameter 0.1 mum) have been "injected" into cells.