Pinched flow coupled shear-modulated inertial microfluidics for high-throughput rare blood cell separation

Abstract

Blood is a highly complex bio-fluid with cellular components making up >40% of the total volume, thus making its analysis challenging and time-consuming. In this work, we introduce a high-throughput size-based separation method for processing diluted blood using inertial microfluidics. The technique takes advantage of the preferential cell focusing in high aspect-ratio microchannels coupled with pinched flow dynamics for isolating low abundance cells from blood. As an application of the developed technique, we demonstrate the isolation of cancer cells (circulating tumor cells (CTCs)) spiked in blood by exploiting the difference in size between CTCs and hematologic cells. The microchannel dimensions and processing parameters were optimized to enable high throughput and high resolution separation, comparable to existing CTC isolation technologies. Results from experiments conducted with MCF-7 cells spiked into whole blood indicate >80% cell recovery with an impressive 3.25 × 10(5) fold enrichment over red blood cells (RBCs) and 1.2 × 10(4) fold enrichment over peripheral blood leukocytes (PBL). In spite of a 20× sample dilution, the fast operating flow rate allows the processing of ∼10(8) cells min(-1) through a single microfluidic device. The device design can be easily customized for isolating other rare cells from blood including peripheral blood leukocytes and fetal nucleated red blood cells by simply varying the 'pinching' width. The advantage of simple label-free separation, combined with the ability to retrieve viable cells post enrichment and minimal sample pre-processing presents numerous applications for use in clinical diagnosis and conducting fundamental studies.

Hydrodynamic mechanisms of cell and particle trapping in microfluidics

“…The so-called multiorifice flow fractionation technique, although yielding relatively high throughput, requires operating in a certain narrow range of flow rates to exhibit decent performance in terms of focusing band width and separation efficiency. Bhagat and coworkers 60 improved this method by introducing a pinching region in addition to the focusing region to maintain the cells of interest around the channel centerline ( Fig. 2(c)).…”

Vortex-aided inertial microfluidic device for continuous particle separation with high size-selectivity, efficiency, and purity

“…5,6 These forces cause cells to migrate across streamlines and order in equilibrium positions based on their size, leading to label-free cell separation, purification and enrichment in a microfluidic device with designed geometries. 7 Applications for separation of cells (erythrocytes/leukocytes, [8][9][10] neuronal cells, 6 cancer cells 11 ), flow cytometry, [12][13][14] and rare cell enrichment [15][16][17] have been developed achieving passive cell and particle manipulation with extremely high throughput.…”

Biophysical Tools for Cellular and Subcellular Mechanical Actuation of Cell Signaling

“…Detailed working principle for these force spectroscopy techniques and their applications to single molecule studies where they have made the most impact have been well described in other reviews (20). In combination with microfluidics, one area where field gradient methods have contributed in recent years is in cell separation applications, where cells can be handled as objects to be moved around (21)(22)(23)(24). Besides whole cell manipulation, these techniques have been harnessed for subcellular mechanical actuation to enable more precise control of cytoskeleton remodeling and signaling pathways.…”