Analysis of Hematocrit-Plasma Separation in a Trifurcated Microchannel by a Diffusive Flux Model

TL;DR

This study uses a diffusive flux model to analyze how a trifurcated microchannel can passively separate blood components, focusing on geometrical and flow parameters to optimize efficiency without damaging cells.

Contribution

It introduces a 3D numerical simulation framework using the diffusive flux model to evaluate microchannel design parameters for blood component separation.

Findings

Smaller channel width improves separation efficiency.

Extended inlet enhances cell-free layer formation.

Lower hematocrit samples yield better separation results.

Abstract

Platelet-enriched plasma and red blood cells (RBC) are needed in the treatment of blood-related diseases, including anaemia and blood cancer. These essential components must be separated from blood in well-designed experimental setups. If active techniques are used, the blood components are likely to be damaged or contaminated while handling. Passive techniques for component separation are preferred, and their design for effectiveness before manufacturing is the subject of this article. Specifically, the performance of a design consisting of a trifurcated microchannel is examined in the framework of 3D numerical simulation, following similar design ideas in recent experimental studies. The influence of geometrical parameters of the channel, such as width and separation arm angle, inlet extension, flow constriction, and flow parameters, including flow rates, hematocrit concentration, and temperature, is studied. The present study utilizes the diffusive flux model (DFM) to model the shear-driven migration of red blood cells (RBC) in a microchannel along with an appropriate rheology model. The physical mechanism driving separation is the formation of the cell-free layer near the walls, using which the separation efficiency and device effectiveness are quantified. It is found that a microchannel with a smaller width and an extended inlet, along with diluted blood samples of lower hematocrit, is effective for greater separation, while the device performance is less sensitive to the flow rates, flow constriction, and the separator angle.