Three Spectrin-Sensitive Dielectric Relaxations in RBC Membrane: Relation to RBC Deformability and Surface Properties

Two spectrin-sensitive relaxations have been reported in the RBC plasma membrane: βs (1.4 MHz, related to the interface β-relaxation) and γ1s (9 MHz, rotation alignment of spectrin-bound dipoles by penetrating electric field). Here, a third (αs) relaxation type is reported within the frequency region of surface (α) relaxation. With low-ion-strength outside media, the adsorption of blood plasma immunoglobulins on RBCs was found to inhibit βs and γ1s relaxations, while αs relaxation was enforced with strong inflammation. The three relaxations are represented by three consecutive segments on the Cole′s plots: Δεrd″.ω against Δεr′ and Δεrd″/ω against Δεr′. Here, ω is the frequency of the field and Δεr* = Δεr′ + j.Δεrd″ is the change in the relative complex dielectric permittivity of RBC suspension at the denaturation temperature of spectrin. The βs segment in Δεrd″.ω against the Δεr′ plot could be regarded as a vector (complex number) whose projection on the vertical axis (the irreversible loss in energy) could express the ability of the plasma membrane to deform (under the impact of shear stress).