Early stage shape change of human erythrocytes after application of electric field pulses.

Erythrocytes which receive electric field pulses are subject to poration, fusion and shape changes due to electrodynamic forces, aminophospholipid perturbation and influences on the normal flip-flop process. The shape change characteristics of cells suspended in different media were analysed after application of rectangular electric field pulses from t=11-44 micros and from E=4-8 kV/cm. Albumin is shown to decelerate the echinocyte shape change within the first few seconds after pulse application. The addition of fluoride and vanadate accelerates the shape change due to their inhibiting influence on the aminophospholipid translocase. For both the duration of the field pulse and its field strength, there exist lower threshold values under which no early stage shape change is observable. The activation energy calculated from the dissipative influence of the electric field alone is smaller than expected, indicating the electrodynamic influence on the flip-flop process. Cell shapes were additionally analysed by contour tracing to focus on the echinocyte spicule distribution after pulse application. This image analysis revealed that, with an increase of both pulse duration and field strength, the shape change velocity and the shape change intensity increase.