Relaxation phenomena in human erythrocyte suspensions

Area of Science:

• Biophysics
• Cell Biology
• Physical Chemistry

Background:

• The Joule heating temperature jump technique previously induced [3H-A1glucose interiorization and hemolysis in human erythrocytes.
• This effect was initially attributed to thermal osmosis.

Purpose of the Study:

• To investigate the mechanisms behind Joule heating-induced red blood cell hemolysis.
• To identify and characterize relaxation processes associated with membrane dynamics and water transport.

Main Methods:

• Application of the Joule heating temperature jump technique to erythrocyte suspensions.
• Turbidity measurements to detect relaxation times.
• Studies on erythrocytes from patients with hematological disorders.
• Experiments with erythrocyte ghosts.

Main Results:

• Four distinct relaxation times were observed: tau1 (~20 µs), tau2 (~5 ms), tlag (~0.1 s), and tau3 (~0.5 s).
• Faster relaxations (tau1, tau2) are linked to water movement in membrane structures, while slower ones (tlag, tau3) relate to membrane rupture and hemolysis.
• Slower relaxations are sensitive to red cell membrane properties, unlike the faster ones.
• Apparent activation energies were determined for tau1, tau2, and tau3.
• Erythrocyte ghosts showed a single relaxation for water permeation and biphasic kinetics for membrane rupture/resealing.

Conclusions:

• Joule heating induces red blood cell hemolysis via both thermal osmosis and rapid dielectric perturbation of cell membranes.
• The identified relaxation processes provide insights into water transport dynamics and membrane integrity.
• These findings contribute to understanding molecular release and cellular system responses to physical stress.