Probing a self-assembled fd virus membrane with a microtubule

Area of Science:

• Colloidal science and self-assembly
• Biophysics and soft matter physics
• Computational materials science

Background:

• Self-assembly of anisotropic colloidal particles creates complex structures with emergent properties.
• Monolayer membranes of rodlike fd viruses are a model system for studying colloidal assembly.
• Polymer depletants induce attractive interactions, influencing membrane formation and stability.

Purpose of the Study:

• To investigate the particle-scale interactions during the penetration of a microtubule through an fd virus monolayer membrane.
• To understand the forces and effects of polymer depletants and particle fluctuations on this interaction.
• To provide insights for ongoing experimental studies on microtubule-membrane interactions.

Main Methods:

• Utilized computer simulations to model the interaction between a microtubule and an fd virus monolayer membrane.
• Modeled viruses and microtubules as hard spherocylinders and depletants as ghost spheres.
• Analyzed the forces, translational/rotational fluctuations, and osmotic pressure effects during membrane penetration.

Main Results:

• The force on the microtubule is zero when fully outside or inside the membrane.
• An initial repulsive force is followed by an attractive force as the microtubule penetrates deeper.
• Rotational fluctuations of viruses significantly influence the interaction more than translational ones; depletant osmotic pressure modulates interaction potentials.

Conclusions:

• Microtubule penetration of fd virus membranes involves complex force dynamics, including repulsion and attraction.
• Particle fluctuations, particularly rotational, and depletant osmotic pressure are critical factors governing the interaction.
• Simulation results offer a mechanistic understanding relevant to experimental microtubule-membrane interaction studies.