The physics of continuous flow centrifugal cell separation.

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Hematology

Background:

• Continuous flow centrifugation is crucial for blood component separation.
• Understanding fluid dynamics, including blood viscosity and shear stress, is key to optimizing separation efficiency.
• Existing models may not fully capture the complex interplay of factors influencing blood separation.

Purpose of the Study:

• To derive governing equations for blood separation in continuous flow centrifuges.
• To model the effects of fluid shear and shear-enhanced diffusion on the separation process.
• To develop predictive equations for species-specific separations and compare them with experimental data.

Main Methods:

• Empirical modeling of blood viscosity.
• Development of models for estimating shear rate during centrifugation.
• Derivation of simplified predictive equations for species-specific separations.
• Experimental validation using an investigational centrifuge.

Main Results:

• Governing equations for blood separation were derived.
• Shear-enhanced diffusion was found to be negligible at the cell-plasma interface.
• Experimental results aligned with theoretical predictions.
• The role of rouleaux formation in conventional centrifuges was discussed.

Conclusions:

• The developed models provide a theoretical basis for understanding and predicting blood separation in continuous flow centrifuges.
• Empirical viscosity models and shear rate estimations are crucial for accurate separation predictions.
• Further research can refine these models for improved clinical and research applications.