Squirming in a viscous fluid enclosed by a Brinkman medium
Herve Nganguia1, Lailai Zhu2, D Palaniappan3
1Department of Mathematical and Computer Sciences, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705, USA.
Physical Review. E
|July 22, 2020
Summary
Microscopic swimmers, like bacteria, may need to liquefy a minimum mucus gel size to move faster. This finding impacts understanding of infections and designing drug delivery microswimmers.
Area of Science:
- Biophysics
- Microbiology
- Fluid Dynamics
Background:
- Cell motility is crucial for biological processes like reproduction and infection.
- The bacterium Helicobacter pylori may enhance its gastric mucus invasion by locally liquefying the mucus gel.
Purpose of the Study:
- To theoretically investigate how a swimmer's generated heterogeneity impacts its own locomotion.
- To model a spherical squirmer in a fluid pocket surrounded by a Brinkman porous medium.
Main Methods:
- Developed a minimal theoretical model for swimmer locomotion.
- Utilized a spherical squirmer model for an exact analytical solution.
- Derived analytical expressions for swimming speed, flow field, and power dissipation.
Main Results:
- Identified a minimum threshold size of liquefied mucus gel required for enhanced swimming speed.
- This threshold can be up to 30% of the swimmer's size.
- Highlighted the significant role of surface actuation details in locomotion.
Conclusions:
- Swimmer locomotion is influenced by the size of the liquefied region and surface properties.
- Findings have implications for understanding bacterial invasion and designing artificial microswimmers for drug delivery.
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