Instability development in heated human erythrocytes

Heated human erythrocytes gradually lose their form-maintaining structure as the temperature is increased to 50°C and can behave in some respects as a viscous fluid. We have developed a technique for heating and stressing these cells that is novel, simple and quantitatively precise. We have applied this technique to heated human erythrocytes and have measured instability development in the cells. We have employed instability growth theory to calculate a value for an effective surface tension which, in contrast to other methods of membrane surface tension measurement sought to minimize the effects of membrane supporting structural elements. The value obtained for the surface tension of the heated erythrocyte membrane was 0.9 · 10^?6 N/m with a range of variation from 0.4 · 10^?6 N/m to 1.4 · 10^?6 N/m. The methods described may be useful for determining fundamental physical parameters such as internal viscosity and interfacial tension in other systems.