One-Step Microfluidic Purification of White Blood Cells from Whole Blood for Immunophenotyping

Abstract

One-step purification of white blood cells (WBCs) is essential to automate blood sample preparation steps for WBC analysis, but conventional methods such as red blood cell (RBC) lysis and density-gradient centrifugation typically require harsh chemical or physical treatment, followed by repeated manual washing steps. Alternative microfluidic separation methods show limited separation performances due to the trade-off between purity and throughput. Herein, an integrated microfluidic device is developed to decouple the trade-off by synergistically combining a slant array ridge-based WBC enrichment unit as a throughput enhancer and a slant, asymmetric lattice-based WBC washing unit as a purity enhancer. The enrichment unit can maintain a high sample-infusion throughput while lowering the flow rate into the washing unit, thus enabling WBC-selective washing without significant influence by the overwhelming number of RBCs and inertial forces. The device delivers efficient separation performances by rejecting 99.9% of RBCs as well as 99.9% of blood plasma from canine and human whole blood in a single round of purification at a high throughput of 60 μL/min. The purified WBC population well preserves the composition of lymphocyte subpopulations, the major components of the adaptive immune system, thus providing the potential for the integrated device to be used as an essential sample-preparation tool for immunologic investigations.

Reagent- and actuator-free analysis of individual erythrocytes using three-dimensional quantitative phase imaging and capillary microfluidics

“…Based on the learnings from the microchannel developed for preparing RBC monolayers, we are attempting to fabricate capillary microchannel devices compatible with different blood cells, including white blood cells and platelets. Recently structured microchannels that exploit deterministic hydrodynamics for WBC separation could be excellent references for expanding the capabilities of our capillary-action-based device 57–59 . Additionally, advanced imaging processing approaches can also be employed 60 or advanced cell segmentation algorithms for 3D imaging 61 to achieve fully automated, high-throughput blood cell characterization.…”

Recent Advances in Microfluidic Technology for Bioanalysis and Diagnostics

“…Kim et al introduced a one-step purification method for white blood cells (WBC) at high flow rates of 60 μL min –1 . It synergistically combines a slant array ridge-based WBC enrichment unit as a throughput enhancer and a slant, asymmetric lattice-based WBC washing unit as a purity enhancer . In a similar context, Zhu et al built a inertial microfluidics cube for fast extraction of white blood cells .…”

“…It synergistically combines a slant array ridge-based WBC enrichment unit as a throughput enhancer and a slant, asymmetric lattice-based WBC washing unit as a purity enhancer. 165 In a similar context, Zhu et al built a inertial microfluidics cube for fast extraction of white blood cells. 166 A highly integrated device for CTC capture from blood samples was recently reported by Tohner and coworkers.…”

Micro-Volume Blood Separation Membrane for In-Situ Biosensing

“…Point-of-care tests (POCT) need to deliver results in a short period of time without relying on large laboratory instruments, while achieving sensitivity and portability at the same time is a key technical challenge in clinical diagnostics. Microfluidic technology is an emerging method to separate nano- to microliter volumes of blood cells by unique channel designs, including flexographic printing, lithography, inkjet printing, screen printing and chemical modification [ 14 , 15 ]. However, these microfluidic separation strategies require complex fabrication procedures and specialized instrumentation, increasing the inconvenience and costs of POCT devices.…”