A low-cost, plug-and-play inertial microfluidic helical capillary device for high-throughput flow cytometry

Abstract

Glass capillary tubes have been widely used in microfluidics for generating microdroplets and microfibers. Here, we report on the application of glass capillary to inertial focusing of microparticles and cells for high-throughput flow cytometry. Our device uses a commercially available capillary tube with a square crosssection. Wrapping the tube into a helical shape induces the Dean vortices that aid focusing of cells or microbeads into a single position. We investigated the inertial focusing of microbeads in the device at various Re and concentrations and demonstrated 3D focusing with $100% efficiency for a wide range of microparticle diameters. We integrated the device with a laser counting system and demonstrated continuous counting of 10 lm microbeads with a high throughput of 13 000 beads/s as well as counting of fluorescently labeled white blood cells in the diluted whole blood. The helical capillary device offers a number of key advantages, including rapid and ultra-low-cost plug-and-play fabrication, optical transparency, and full compatibility with bright field or fluorescent imaging, easy re-configurability of the device radius for tuning focusing behavior, and ability to rotate for easy side-wall observation. With precise and consistent 3D focusing of microbeads and cells with a wide range of sizes at high throughput and without the use of sheath flows, we envision that this simple capillary-based inertial microfluidic device will create new opportunities for this technique to be widely adopted in the laboratory research. Published by AIP Publishing. [http://dx

Mapping inertial migration in the cross section of a microfluidic channel with high-speed imaging

“…Since then, increasing attention has been poured into the field, and numerous investigators have focused on unleashing the potential of inertial microfluidics. Numerous microfluidic systems based on inertial migration have been reported to tackle a wide range of challenges, including label-free cell sorting [8][9][10] , efficient focusing for flow cytometry [11][12][13] , cell mechanotyping 14,15 , and the high-throughput isolation of circulating tumor cells (CTCs) for liquid biopsy applications [16][17][18][19][20][21][22] .…”

Sheathless Microflow Cytometry Using Viscoelastic Fluids

“…7 . In general, three main focusing methods have been used for 3D focusing: hydrodynamic 8 , 13 , 14 , 17 – 19 , 26 , 65 – 69 , acoustic 24 , 71 , 72 , and inertial 28 , 29 , 43 , 73 focusing. Some studies use a combination of these methods for focusing in two lateral dimensions 5 , 6 , 70 .…”

“…Inertial focusing has been investigated for straight channels of different geometries including circular 39 , square 40 , rectangular 41 and even unusual cross sections 42 , resulting in multiple-line focusing. Implementing curved structures creates Dean drag force which results in focusing of particles into a narrower region 29 , 43 .To reach single-train of particles, the structure of the channel should be engineered or different structures of channels should be integrated in a specific sequence.…”

Progress of Inertial Microfluidics in Principle and Application

“…With the development of 3D technology, glass capillary tubes have been widely used in microfluidics. Wang [ 99 ] investigated a wide-diameter range of microparticles in a 3D spiral inertial focusing device at various R e values, and realized the separation with 100% efficiency ( Figure 10 e). In addition to the single spiral-channel, the double spiral-channel [ 100 ] and the gradual expanding channel [ 101 ] can be used to separate multi-sized particles.…”

“…Ref. [ 99 ]. Rights managed by AIP Publishing; ( f ) Method to isolate bacteria from whole blood rapidly based on principle of Dean flow.…”