Averaged implicit hydrodynamic model of semiflexible filaments

Area of Science:

• Physics
• Biophysics
• Polymer Science

Background:

• Hydrodynamic interactions significantly influence the dynamics of semiflexible filaments.
• Previous models often neglected these effects or used simplified approximations.
• Understanding these interactions is crucial for modeling biological polymers like actin.

Purpose of the Study:

• To develop a computationally efficient method for incorporating hydrodynamic interactions into semiflexible filament dynamics.
• To accurately model the effects of hydrodynamic screening and nonuniform drag.
• To provide a framework for simulating filament behavior with greater realism.

Main Methods:

• Developed a hydrodynamics model based on a string-of-beads idealization.
• Employed an implicit, infinite-order Stokes superposition to capture hydrodynamic interactions.
• Averaged hydrodynamic velocities over bead sections, treating end beads separately for improved drag resolution.
• Integrated the method into an existing string-of-rods model for semiflexible filaments.

Main Results:

• The model successfully reproduces experimental data for the mean-squared displacement of actin filaments.
• Demonstrated that hydrodynamic interactions confine fluctuating filaments.
• Showed that induced solvent flow contributes significantly to filament interior velocities.

Conclusions:

• The developed method provides an accurate and efficient way to include hydrodynamic interactions in filament dynamics.
• This approach enhances the simulation of semiflexible polymers, with implications for biophysics.
• The findings offer insights into the role of hydrodynamic screening in polymer behavior.