An Enhanced Spring-Particle Model for Red Blood Cell Structural Mechanics: Application to the...

Area of Science:

• Biophysics
• Computational Biology
• Cellular Mechanics

Background:

• Red blood cells (RBCs) exhibit shape transformations, such as stomatocytes and echinocytes, from their usual discocyte form.
• The stomatocyte-discocyte-echinocyte (SDE) transformation is a dynamic process observed in RBCs.
• Current spring-particle RBC (SP-RBC) models struggle to numerically predict the complete SDE transformation due to bending model instabilities.

Purpose of the Study:

• To develop an enhanced SP-RBC model capable of reproducing the full SDE transformation.
• To extend the predictive capabilities of numerical RBC models for shape dynamics.
• To investigate RBC shape changes under varying biophysical conditions.

Main Methods:

• An advanced bending model was integrated into the existing SP-RBC framework.
• Numerical simulations were performed to predict vesicle and RBC shapes across a range of reduced volumes and membrane area differences (MAD).
• Predicted shapes were compared against experimental observations for validation.

Main Results:

• The enhanced SP-RBC model successfully predicted transformed vesicle and RBC shapes.
• High agreement was observed between simulated and experimentally determined RBC shapes.
• Vesicle and SDE transformation phase diagrams were generated, including novel shape boundaries for RBCs.

Conclusions:

• The proposed enhanced SP-RBC model accurately captures the full SDE transformation.
• This model provides a robust tool for predicting RBC mechanics and shape dynamics.
• The study establishes new shape boundaries for RBCs based on reduced volume and reduced MAD.