Paper-Based Flow Fractionation System Applicable to Preconcentration and Field-Flow Separation

Abstract

We present a novel paper-based flow fractionation system for preconcentration and field-flow separation. In this passive fluidic device, a straight channel is divided into multiple daughter channels, each of which is connected with an expanded region. The hydrodynamic resistance of the straight channel is predominant compared with those of expanded regions, so we can create steady flows through the straight and daughter channels. While the expanded regions absorb a great amount of water via capillarity, the steady flow continues for 10 min without external pumping devices. By controlling the relative hydrodynamic resistances of the daughter channels, we successfully divide the flow with flow rate ratios of up to 30. Combining this bifurcation system with ion concentration polarization (ICP), we develop a continuous-flow preconcentrator on a paper platform, which can preconcentrate a fluorescent dye up to 33-fold. In addition, we construct a field-flow separation system to divide two different dyes depending on their electric polarities. Our flow fractionation systems on a paper-based platform would make a breakthrough for point-of-care diagnostics with specific functions including preconcentration and separation.

Highly Sensitive Paper-based Analytical Devices with the Introduction of a Large-Volume Sample via Continuous Flow

“…39 The expanded regions absorb a great amount of water via the capillary force, and the steady flow continues for 10 min without any external pumping devices. Recently, a quasi-steady flow was generated using a fan-shaped geometry connected to an analysis channel, whereby a solution could be pulled through the detection channel into a large reservoir with a fan shape.…”

Folding-paper-based preconcentrator for low dispersion of preconcentration plug

“…The results show that a diameter of 9 mm is the optimal size for the outlet reservoir. From Darcy's law, the flow rate can be expressed as follows [20,24,25]:…”

“…Recently, Kwak and Hong et al proposed a paper-based ICP preconcentrator to facilitate extraction. Hong et al developed a continuous-flow preconcentrator with a bifurcation system to collect and separate the samples [19,20] Recently, we proposed a paper-based preconcentrator, which preconcentrates FITC-albumin with a high preconcentration factor of up to 310-fold for 400 s [3], however, there are limitations in applying the preconcentrator for using external analytical devices because of dispersion of preconcentrated sample plug. In this study, a 3D foldable-paper-based ICP preconcentration system is proposed for obtaining a preconcentration plug with minimal dispersion.…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2014–2016)

“…Nafion has been widely used in μPAD for sample preconcentration . Phan and coworkers developed a μPAD by simply integrating microporous paper and nanoporous nafion membrane and then laminating with plastic film without printing hydrophobic materials such as wax, the schematic was shown in Fig.…”