Interaction forces between red cells agglutinated by antibody. I. Theoretical

Area of Science:

• Fluid dynamics
• Biophysics
• Rheology

Background:

• Hydrodynamic interactions govern particle behavior in fluid flow.
• Previous models by Arp and Mason (1977) and Brenner and O'Neill (1972) provide foundational methods.
• Understanding forces on biological cells in flow is crucial for cell separation and analysis.

Purpose of the Study:

• To derive and present explicit expressions for hydrodynamic forces acting on doublets of spheres.
• To apply this theoretical framework to human red blood cell doublets cross-linked by antibodies.
• To enable computation of the force required to break apart red blood cell doublets.

Main Methods:

• Utilized the matrix formulation of hydrodynamic resistances in creeping flow.
• Solved the Brenner-O'Neill force-torque vector equation in terms of particle and external flow field coordinates.
• Applied the derived equations to model red blood cell doublets with a fixed interparticle distance (h = 20 nm).

Main Results:

• Derived expressions for normal and shear forces acting on a doublet of spheres.
• Successfully applied the theory to model human red blood cell doublets.
• Established a method to compute the hydrodynamic force necessary for doublet separation.

Conclusions:

• The developed method provides a robust framework for analyzing hydrodynamic forces on particle doublets.
• This approach is applicable to biological systems, such as antibody-linked red blood cells.
• The study facilitates the calculation of forces critical for understanding cell-cell interactions and separation dynamics.