Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
Biosens Bioelectron. 2018 Jan 15;99:361-367. doi: 10.1016/j.bios.2017.07.073. Epub 2017 Aug 1.
A paper-based microfluidic device based on unconventional principle was developed and used to detect lead ions through a two-step process including heated incubation and subsequent mixing. The device was made by generating a superhydrophobic pattern, which defines channel and reservoir barriers, on a water-impermeable paper substrate, followed by loading and drying the reagents in the defined reservoirs. Different from the conventional paper-based devices that are made of water-permeable paper, the as-prepared device holds water drops in discrete reservoirs, and the water drops will not move unless the device is titled along the direction of the predefined channels. In this way, the liquid samples applied onto the device are handled as individual drops and could be stored, transported, and mixed on demand. Different from the conventional paper-based devices that use capillary force to drive liquid, our new device uses wetting and gravity as driving force. We name this operation principle suspending-droplet mode paper-based device (SD-μPAD). The use of a Teflon contact-printing stamp makes the production of such devices rapid, cost efficient, and mass productive. Utilizing a G-quadruplex-based luminescence switch-on assay, we demonstrated rapid, convenient, highly sensitive, and low cost detection of lead(II) ions in water samples, using a custom made battery-powered portable device, and a smart phone as the detector.
一种基于非传统原理的纸质微流控装置被开发出来，并通过包括加热孵育和随后混合的两步过程来检测铅离子。该装置通过在不透水的纸基底上生成超疏水图案来制造，该图案定义了通道和储液器的障碍物，然后在定义的储液器中加载和干燥试剂。与传统的由透水纸制成的纸质设备不同，所制备的设备将水滴保持在离散的储液器中，除非设备沿着预定通道的方向倾斜，否则水滴不会移动。这样，施加到设备上的液体样品被处理为单个液滴，可以按需储存、运输和混合。与传统的使用毛细作用力驱动液体的纸质设备不同，我们的新设备使用润湿和重力作为驱动力。我们将这种操作原理命名为悬滴模式纸质设备（SD-μPAD）。使用聚四氟乙烯接触印刷邮票使得这种设备的制造快速、经济高效且可以大规模生产。我们利用基于 G-四链体的发光开关分析，使用定制的电池供电便携式设备和智能手机作为检测器，在水样中快速、方便、高灵敏且低成本地检测铅（II）离子。
