Active Digital Microfl uidic Paper Chips with Inkjet- Printed Patterned Electrodes
Active Digital Microfl uidic Paper Chips with Inkjet- Printed Patterned Electrodes
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DOI：
10.1002/adma.201305014
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发表时间：
2014-04-01
影响因子：
29.4
通讯作者：
Shin, Kwanwoo
中科院分区：
文献类型：
--
作者：
Ko, Hyojin;Lee, Jumi;Shin, Kwanwoo
凭借纤维素的丰富性和物理特性，纸基设备通常被认为是廉价、便携式和简单设备的新颖平台。[1-4]这些优点推动了多种纸基应用的发展，包括生物化学、[5]机械、[6]和电气应用。[2, 7]纸张的另一个独特特性——其允许精确书写和打印的能力——也被用来开发各种新颖的设备，[8-14]例如纸，[9, 12] 喷墨印刷化学传感纸，[11, 13] 和电子纸显示器。[14]第一个有前途的纸质诊断芯片由 Whiteside 小组于 2007 年推出，[15]，最近纸基流体设备受到了极大的关注。[1,5,8-14]纸基流体设备主要具有便携性、可吸收性、一次性性和比传统流体设备显着降低成本的优势，传统流体设备需要通过泵和阀门进行细致的流体控制。[16]大多数传统纸芯片通常使用选择性技术从亲水纸转换为疏水纸，反之亦然，并且样品通过由疏水防水壁隔离的亲水图案通道的流动是由吸引力和排斥毛细力之间的竞争驱动的。 [5]因此，这些无源芯片有两个主要限制： a) 液体样品作为连续流的传输主要是通过纤维素纤维的毛细管力； b) 反应发生在图案化阵列的末端，化学试剂已预先植入或印刷在图案化阵列上作为检测或诊断探针。虽然之前对纸质微流控芯片的研究主要集中在完全集成的芯片实验室 (LOC) 设备 [16] 以及仅利用纸质本身的被动毛细力来操纵二维或三维通道中的连续流体 [7, 17] 以降低成本，但尚未尝试通过纸质微流控芯片来操纵电滴驱动使用外部电源，大概是因为在纸质设备上实现电路的复杂性。[1,2,18,19]最近引入了一种基于表面能陷阱的液滴操纵技术，其中手动改变磁场以实现液滴传输和融合并允许液体分配；然而，缺乏电力实施限制了该技术的可编程自动延时运动。 [20]在这项研究中，我们提出了一种新颖的纸基流体芯片，它通过电润湿技术在纸上实现电输入来实现全方位的流体操作。[21-25]这种动力纸基微流体芯片被称为有源纸基开放芯片（APOC），其主要特征是离散液滴体积，是开放型芯片。[26-28]有源和无源纸基微流体器件之间最显着的区别是图案化阵列的存在纸上的电极，使得基底表面上的毛细管力可以通过外部电压主动调节。在纸上驱动液滴的基本原理是利用电场来调节液滴与表面下方的反电极之间的电润湿引起的表面张力。因此我们的APOC比传统的无源传输芯片具有独特的优势。本质上，在我们的 APOC 上，可以对具有预先确定的量化体积的样品滴进行稀释、合并和/或混合。在与目标液滴发生主要反应之前，可以在准确的时间使用各种试剂进行预编程的连续处理……
By virtue of the abundance and physical properties of cellulose, paper-based devices are often considered to be novel platforms for inexpensive, portable, and simple devices.[1–4] These advantages have motivated the development of diverse paper-based applications, including biochemical,[5] mechanical,[6] and electrical applications.[2, 7] Another unique characteristic of paper—its ability to permit precise writing and printing—has also been used to develop various novel devices,[8–14] such as patterned bioassays on paper,[9, 12] inkjet-printed chemical-sensing paper,[11, 13] and an electronic paper display.[14] The first promising paper diagnostic chip was introduced by the Whiteside group in 2007,[15] and recently significant attention has been paid to paper-based fluidic devices.[1, 5, 8–14] Paperbased fluidic devices primarily offer the advantages of portability, absorbability, disposability, and significantly lower costs over conventional fluidic devices, which require meticulous fluidic controls with pumps and valves.[16] Most conventional paper chips commonly use a selective technique to convert from hydrophilic to hydrophobic paper or vice versa, and the flow of the sample through hydrophilic-patterned channels isolated by hydrophobic, waterproof walls is actuated by the competition between attractive and repulsive capillary forces.[5] These passive chips, therefore, have two principal limitations: a) transport of the liquid sample as a continuous flow is primarily by the capillary force of the cellulose fibers; and b) reactions occur at the terminals of the patterned array on which the chemical reagents have been pre-implanted or printed as detecting or diagnostic probes.Whereas previous research on paper microfluidic chips focused on fully integrated lab-on-a-chip (LOC) devices [16] and on manipulating a continuous fluid in two-or three-dimensional channels [7, 17] by utilizing only the passive capillary force of the paper itself to reduce costs, no attempt has been made to manipulate electric drop actuation by using external power sources, presumably because of the complexities involved in implementing electric circuits on paper devices.[1, 2, 18, 19] A surface-energy trapbased drop manipulation technique in which a magnetic field was manually varied to enable drop transport and fusion and to allow liquid to be dispensed was introduced recently; however, the absence of electric implementation has limited the programmable automated time-delay motion of the technique.[20] In this study, we present a novel, paper-based fluidic chip that allows the full range of fluidic operations by implementing an electric input on paper via an electrowetting technique.[21–25] This powered paper-based microfluidic chip, which is known as an active paper open chip (APOC), is primarily characterized by discrete drop volumes and is an open-type chip.[26–28] The most noticeable difference between active and passive paper-based microfluidic devices is the existence of a patterned array of electrodes on the paper such that the capillary force on the substrate’s surface can be actively tuned with an external voltage. The basic principle of actuating drops on paper is the use of an electric field to adjust the electrowetting-induced surface tension between a drop and a counter-electrode beneath the surface. Hence our APOC has unique advantages over the conventional passive transporting chips. Essentially, on our APOC, it is possible to perform diluting, merging and/or mixing of the sample drops, having pre-determined quantized volumes. Prior to the main reaction with a target drop, pre-programmed sequential treatments with various reagents at exact time can be …