Department of Chemical and Biomedical Engineering, University of Maine, 5737 Jenness Hall, Orono, Maine 04469.
Biointerphases. 2019 Aug 20;14(4):041005. doi: 10.1116/1.5114804.
Point-of-care (POC) detection and diagnostic platforms provide critical information about health and safety conditions in austere and resource-limited settings in which medical, military, and disaster relief operations are conducted. In this work, low-cost paper materials commonly used in POC devices are coated with liquid-infused polymer surfaces and folded to produce geometries that precisely localize complex liquid samples undergoing concentration by evaporation. Liquid-infused polymer surfaces were fabricated by infusing silicone-coated paper with a chemically compatible polydimethylsiloxane oil to create a liquid overlayer. Tests on these surfaces showed no remaining bacterial cells after exposure to a sliding droplet containing a concentrated solution of Escherichia coli or Staphylococcus aureus, while samples without a liquid layer showed adhesion of both microdroplets and individual bacterial cells. Folding of the paper substrates with liquid-infused polymer surfaces into several functional 3D geometries enabled a clean separation and simultaneous concentration of a liquid containing rhodamine dye into discrete, predefined locations. When used with bacteria, which are known for their ability to adhere to nearly any surface type, functional geometries with liquid-infused polymer surfaces concentrated the cells at levels significantly higher than geometries with dry control surfaces. These results show the potential of synergistically combining paper-based materials with liquid-infused polymer surfaces for the manipulation and handling of complex samples, which may help the future engineering of POC devices.
即时检测和诊断平台提供了关于在进行医疗、军事和救灾行动的恶劣和资源有限环境中的健康和安全状况的关键信息。在这项工作中，低成本的纸张材料通常用于即时检测设备，其表面涂覆有液体注入聚合物，并折叠成特定的几何形状，精确地定位通过蒸发浓缩的复杂液体样本。液体注入聚合物表面是通过将涂有硅树脂的纸张注入化学相容的聚二甲基硅氧烷油来制造液体覆盖层而制成的。对这些表面的测试表明，在含有浓缩大肠杆菌或金黄色葡萄球菌溶液的滑动液滴暴露后，没有残留的细菌细胞，而没有液体层的样本显示出微滴和单个细菌细胞的粘附。将涂有液体注入聚合物的纸张基底折叠成几个功能 3D 几何形状，可以干净地分离并同时将含有罗丹明染料的液体浓缩到离散的、预定义的位置。当用于细菌时，众所周知，细菌能够附着在几乎任何类型的表面上，具有液体注入聚合物表面的功能几何形状将细胞浓缩到比具有干燥对照表面的几何形状高得多的水平。这些结果表明，将纸基材料与液体注入聚合物表面协同结合用于复杂样本的处理和操作具有很大的潜力，这可能有助于即时检测设备的未来工程设计。
