Theory of myelin coiling

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Myelin structures, essential for nerve insulation, exhibit complex morphologies.
• Understanding the physical forces governing myelin formation and coiling is crucial for neurobiology.

Purpose of the Study:

• To propose a novel biophysical model explaining the coiling of myelins composed of fluid bilayers.
• To investigate the role of bilayer lateral tension in myelin morphology.

Main Methods:

• Development of a theoretical model allowing non-coaxial bilayer cylinders and variable lateral tension.
• Mechanical analysis analogous to Euler buckling of elastic rods.
• Calculations to determine conditions for myelin coiling based on free energy minimization.

Main Results:

• The proposed model demonstrates that sufficient bilayer lateral tension induces myelin coiling to reduce free energy.
• Myelin coiling is mechanistically analogous to Euler buckling.
• A bilayer lateral tension of approximately 1 dyne/cm can induce coiling in typical lipid bilayers.

Conclusions:

• Bilayer lateral tension is a significant factor in determining the morphology of myelinic structures.
• The model provides a framework for understanding how mechanical forces influence myelin organization.
• This work highlights the importance of lipid bilayer mechanics in biological structure formation.