Biomedical Engineering Department, McGill University, 740 Dr Penfield Avenue, Montreal, QC H3A 1A4, Canada.
Lab Chip. 2011 Aug 7;11(15):2618-24. doi: 10.1039/c1lc20336c. Epub 2011 Jun 15.
We present and characterize cotton yarn and knots as building blocks for making microfluidic circuits from the bottom up. The yarn used is made up of 200-300 fibres, each with a lumen. Liquid applied at the extremity of the yarn spontaneously wets the yarn, and the wetted length increases linearly over time in untreated yarn, but progresses according to a square root relationship as described by Washburn's equation upon plasma activation of the yarn. Knots are proposed for combining, mixing and splitting streams of fluids. Interestingly, the topology of the knot controls the mixing ratio of two inlet streams into two outlet yarns, and thus the ratio can be adjusted by choosing a specific knot. The flow resistance of a knot is shown to depend on the force used to tighten it and the flow resistance rapidly increases for single-stranded knots, but remains low for double-stranded knots. Finally, a serial dilutor is made with a web made of yarns and double-stranded overhand knots. These results suggest that yarn and knots may be used to build low cost microfluidic circuits.
我们提出并描述了棉线和线结作为自下而上制作微流控回路的构建块。所使用的纱线由 200-300 根纤维组成，每根纤维都有一个内腔。液体施加在线纱的末端时，会自发润湿线纱，在未经处理的线纱中，润湿长度随时间呈线性增加，但在线纱经等离子体激活后，根据 Washburn 方程，润湿长度会按照平方根关系增加。线结可用于组合、混合和分流液体。有趣的是，线结的拓扑结构控制着两股入口流进入两股出口线纱的混合比例，因此可以通过选择特定的线结来调整混合比例。研究表明，线结的流动阻力取决于用于收紧线结的力，对于单股线结，流动阻力迅速增加，但对于双股线结，流动阻力仍然较低。最后，用由线纱和双股反手线结制成的网制作了一个串联稀释器。这些结果表明，线纱和线结可用于构建低成本微流控回路。
