Department of Mechanical Engineering, Sogang University , Seoul, 121-742, Republic of Korea.
Center for BioMicrosystems, Korea Institute of Science and Technology , Seoul, 136-791, Republic of Korea.
Anal Chem. 2016 Feb 2;88(3):1682-7. doi: 10.1021/acs.analchem.5b03682. Epub 2016 Jan 8.
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.
我们提出了一种新颖的基于纸张的流分离系统，用于预浓缩和场流分离。在这个被动流控装置中，直通道被分为多个子通道，每个子通道都与一个扩展区域相连。与扩展区域相比，直通道的流体动力学阻力占主导地位，因此我们可以通过直通道和子通道创建稳定的流动。虽然扩展区域通过毛细作用吸收了大量的水，但稳定的流动可以在没有外部泵送设备的情况下持续 10 分钟。通过控制子通道的相对流体动力学阻力，我们成功地以高达 30 的流速比分配了流量。我们将这种分叉系统与离子浓度极化 (ICP) 结合，在纸张平台上开发了一种连续流动预浓缩器，可以将荧光染料浓缩 33 倍。此外，我们构建了一种场流分离系统，可以根据染料的极性将两种不同的染料分开。我们基于纸张的流分离系统将在即时诊断方面取得突破，具有预浓缩和分离等特定功能。
