Modeling tissue-scale ciliary transport and mixing in three-dimensional Newtonian flow

Area of Science:

• Biophysics
• Respiratory Physiology

Background:

• Mucociliary clearance is a vital respiratory defense mechanism.
• Cilia propel mucus and trapped particles via rhythmic motion.
• The effects of cilia density and distribution on tissue-scale transport are not well understood.

Purpose of the Study:

• To investigate the impact of cilia density, cluster spacing, and metachrony on fluid mixing and transport.
• To model mucociliary clearance at the tissue scale using 3D simulations.

Main Methods:

• Three-dimensional (3D) computational fluid dynamics (CFD) simulations.
• Modeling Newtonian fluid as a mucus approximation.
• Varying parameters: ciliary density, cluster spacing, and metachronal wave patterns.

Main Results:

• Cilia clusters create flow swirls dependent on ciliary density.
• Individual clusters induce upward and horizontal transport with mixing.
• Optimal spacing between clusters improves horizontal transport efficiency.
• Metachronal waves enhance mixing but decrease net transport.

Conclusions:

• Cilia configuration significantly influences fluid mixing and transport dynamics.
• Findings offer insights into cilia-driven transport principles for bio-inspired engineering.
• Further research is needed for physiologically accurate mucus transport modeling.