Investigating the effects of membrane deformability on artificial capsule adhesion to the functionalized surface

Area of Science:

• Biomedical Engineering
• Computational Biology
• Materials Science

Background:

• Cellular adhesion is vital for biomedical technologies, including cell separation and targeting.
• Cell deformability significantly influences rolling and adhesion dynamics under shear flow.
• Understanding these mechanics is key to designing effective cell-based therapies.

Purpose of the Study:

• To numerically investigate the impact of nonlinear capsule membrane material behavior (elastic-plastic vs. strain hardening) on rolling and adhesion.
• To analyze how mechanical properties influence cell-substrate interactions under shear flow.
• To model receptor-ligand binding kinetics in conjunction with capsule mechanics.

Main Methods:

• Utilized the Immersed Boundary Method for simulating deformable capsule rolling in shear flow.
• Employed Monte Carlo simulations with the Bell model for receptor-ligand interactions.
• Modeled spherical capsules with Mooney-Rivlin strain energy functions for membrane behavior.

Main Results:

• Strain hardening capsules exhibited smoother, slower rolling and larger contact areas than elastic-plastic capsules.
• A lubrication film created a 'dimple' effect, reducing full substrate contact.
• Strain hardening capsules showed a 37% increase in average total bond force compared to elastic-plastic capsules.

Conclusions:

• Capsule mechanical properties critically influence rolling behavior and binding kinetics.
• Nonlinear material behavior, specifically strain hardening, enhances adhesion and bond forces.
• Finite membrane deformation significantly couples hydrodynamic forces with receptor-ligand interactions.