Physical properties of pathological human erythrocytes: II.-A comparative electron spin resonance study of erythrocyte membrane in homozygous β-thalassemia

A contribution to the study of the physical properties of the human-erythrocyte membrane has been obtained by applying electron spin resonance spectroscopy with three spin labels at different penetration levels in the membrane. The order parameter S as a measure of the membrane fluidity and the hyperfine coupling constant a~ as a measure of the membrane polarity have been determined. A comparative study of S and a~ between normal and homozygous fl-thalassemic erythrocytes has been performed. Results showed an increased polarity and a decreased fluidity in the pathological erythrocyte membrane as compared to the normal one. A model for understanding these differences has been proposed.