Continuous hydrophoretic separation and sizing of microparticles using slanted obstacles in a microchannel

Abstract

We report a microfluidic separation and sizing method of microparticles with hydrophoresis--the movement of suspended particles under the influence of a microstructure-induced pressure field. By exploiting slanted obstacles in a microchannel, we can generate a lateral pressure gradient so that microparticles can be deflected and arranged along the lateral flows induced by the gradient. Using such movements of particles, we completely separated polystyrene microbeads with 9 and 12 microm diameters. Also, we discriminated polystyrene microbeads with diameter differences of approximately 7.3%. Additionally, we measured the diameter of 10.4 microm beads with high coefficient of variation and compared the result with a conventional laser diffraction method. The slanted obstacle as a microfluidic control element in a microchannel is analogous to the electric, magnetic, optical, or acoustic counterparts in that their function is to generate a field gradient. Since our method is based on intrinsic pressure fields, we could eliminate the need for external potential fields to induce the movement of particles. Therefore, our hydrophoretic method will offer a new opportunity for power-free and biocompatible particle control within integrated microfluidic devices.

DNA-based highly tunable particle focuser

“…On the other hand, our DNA-based method separates a wide dynamic range of particle sizes (1-10 mm) in a single step, and the relatively wide separation region (50 mm) enables clogging-free operation without any complicated particle removal steps, which is an obvious advantage over the existing obstacle arrays-based methods [31][32][33] for biological samples with heterogeneous particle sizes. We expect that this facile DNA-based separation can be applied to various size-based analytical tools, for example, isolation of white blood cells from whole blood 15 .…”

Hydrodynamic mechanisms of cell and particle trapping in microfluidics

“…Recent progress and potential future directions in the area of inertial microfluidics are discussed in a recent review article by Di Carlo. 73 Even though prototype systems utilizing inertial microfluidics show more rapid and high-throughput outcomes compared to other promising techniques, such as microfiltration, 26,74,75 deterministic lateral displacement, 30,[76][77][78] and hydrophoresis, 79,80 they lack the ability to increase the concentration of the target cells to a significant value. This issue is recently resolved by combining microscale laminar vortices with inertial focusing.…”

Nondimensional analysis of particle behavior during cross-type optical particle separation

“…With the development of microfabrication techniques, various methods of particle separation have been developed, such as dielectrophoretic [4,5], magnetophoretic [6,7], hydrophoretic [8,9], and optical separation methods [10][11][12][13][14][15][16][17][18]. Optical particle separation has some advantages over the other methods: relatively simple structures can be used, resulting in easy to control separation characteristics, and pre-and posttreatments of the medium or separated particles are not required.…”