title: 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.
authors.affiliation: Department of Mechanical Engineering, Sogang University , Seoul, 121-742, Republic of Korea.
authors.forename: Seokbin
authors.initials: S
authors.lastname: Hong
authors.affiliation: Center for BioMicrosystems, Korea Institute of Science and Technology , Seoul, 136-791, Republic of Korea.
authors.forename: Rhokyun
authors.initials: R
authors.lastname: Kwak
authors.affiliation: Department of Mechanical Engineering, Sogang University , Seoul, 121-742, Republic of Korea.
authors.forename: Wonjung
authors.initials: W
authors.lastname: Kim