Formation and resealing of pores of controlled sizes in human erythrocyte membrane.

Abstract

APPLICATION of an electric pulse, at field intensities of a few kV cm−1 and of duration in the µs range, to an isotonic suspension of erythrocytes is known to cause haemolysis of the red cells1–4. Studies from different laboratories suggest that the haemolysis is due to the field-induced transmembrane potential1,3,4. Our recent experiments5 indicate that once the transmembrane potential reaches a threshold of approximately 1 V, which corresponds to an applied field of 2.2 kV cm−1, the erythrocyte membrane becomes leaky to normally impermeant ions or molecules. The permeation of solutes leads to the swelling and eventual lysis of the red cells. This type of haemolysis is known as colloid osmotic haemolysis6,7. The voltage-induced permeability change is consistent with the formation of pores in the membrane. We show here that the size of these pores can be varied in a controlled manner, and that the leaky membrane can be resealed while the haemolysis is prevented. Foreign molecules have successfully been incorporated into the resealed, but otherwise intact, erythrocytes.