Elasto-plasticity in wrinkled polymerized lipid membranes.

Area of Science:

• Biophysics
• Materials Science

Background:

• Biomembranes exhibit both elastic and plastic deformation properties.
• Understanding the physical basis of irreversible membrane deformation is crucial for cell biology.

Purpose of the Study:

• To investigate the mechanical behavior of partially polymerized biomembranes.
• To determine the relationship between polymerization and membrane deformability.
• To explore the physical mechanisms underlying irreversible shape changes in red blood cells.

Main Methods:

• Neutron scattering experiments were performed on partially polymerized wrinkled membranes.
• Fractal dimension analysis was used to measure the yield stress of the membranes.
• Comparison of polymerized and non-polymerized membrane behavior.

Main Results:

• Partially polymerized membranes exceeding a critical polymerization degree do not return to their original spherical shape.
• These membranes become rigid and retain their wrinkled morphology.
• Yield stress is directly related to the degree of polymerization, likely due to quenched lipid diffusion caused by 2D disorder.

Conclusions:

• Polymerization induces irreversible plastic deformations in biomembranes.
• The findings provide a physical explanation for the altered shapes of echinocytes, acanthocytes, and malaria-infected red blood cells.
• This research highlights the role of lipid diffusion and membrane mechanics in cell morphology.