University of Massachusetts - Food Science, 100 Holdsworth Way, 246 Chenoweth Laboratory, Amherst, Massachusetts 01003, USA.
Analyst. 2013 Sep 7;138(17):4998-5004. doi: 10.1039/c3an01114c. Epub 2013 Jul 5.
Paper-fluidic devices have become an emerging trend for micro total analysis systems (microTAS) in the bioengineering field due to their ability to maintain the rapid, sensitive and specific attributes of microfluidic devices. Subsequently, paper-fluidic devices are also more portable, have a lower production cost and are easier to use. However, one of the obstacles in developing paper fluidic devices is the limited ability to control the rate of fluid flow during an assay. In our project, we use electrowetting on dielectrics where a dielectric, which is normally hydrophobic, is polarized and becomes hydrophilic. We have fabricated paper-fluidic devices by inkjet printing and spraying conductive hydrophobic electrodes/valves in conjunction with conductive hydrophilic electrodes which are able to stop the fluid front of phosphate buffered saline (PBS). The hydrophobic valves were then actuated by an applied potential which altered the fluorinated monolayer on the electrode. As the applied potential between the electrodes was increased, the amount of time for the fluid front to pass the valve decreased because the monolayer was altered faster. However, we did not observe significant differences in time as we increased the distance between the electrodes. The valves were also incorporated in a lateral flow assay where the device was used to detect Saccharomyces cerevisiae rRNA sequences. With the ability to control the fluid flow in a paper-fluidic device, more complex and intricate assays can be developed, which not only can be applied in the biomedical, food and environmental fields, but also can be used in low resource settings for the detection of diseases.
纸基流体器件由于其能够保持微流控器件的快速、灵敏和特异性等特点，在生物工程领域已成为微全分析系统（microTAS）的新兴趋势。随后，纸基流体器件也更便于携带、生产成本更低且更易于使用。然而，开发纸基流体器件的障碍之一是在分析过程中对流体流速的控制能力有限。在我们的项目中，我们使用介电润湿，其中介电体通常是疏水的，经过极化后变为亲水的。我们通过喷墨打印和喷涂导电疏水电极/阀，并结合能够阻止磷酸盐缓冲盐水（PBS）流体前缘的导电亲水电极来制造纸基流体器件。然后，通过施加电势来驱动疏水阀，从而改变电极上的氟化物单层。随着电极之间施加的电势增加，流体前缘通过阀的时间减少，因为单层改变得更快。然而，当我们增加电极之间的距离时，我们并没有观察到时间上的显著差异。这些阀也被整合到横向流动分析中，该设备用于检测酿酒酵母 rRNA 序列。通过控制纸基流体器件中的流体流动，可以开发更复杂和精细的分析，不仅可以应用于生物医学、食品和环境领域，还可以用于资源匮乏的环境中，用于疾病的检测。
