Fundamental Investigations of Thread-Based Separations

Thread-based microfluidics is an emerging concept that shows great promise for its applications as an inexpensive, portable chromatographic technology. The kinds of thread used in this study are low-cost, low-volume, and widely available. The design is simple. A cotton thread can transport and separate mixtures via capillary action; no external power source was used for pumping. Threads with different hydrophobicity are used in an effort to optimize and understand chromatographic parameters in the system. The hydrophobicity of the threads was altered by changing levels of exposure to an oxygen plasma.  A simple mixture of dyes, for which separations can be visually observed, have been used as analytes.  Creating these thread-based devices required consideration of the mobile phase which dictates the rate at which fluids wick along the thread, introduction of reagents and sample mixtures onto the thread, and defining an easily readable end point for the chromatography. Thread-based chromatographic devices have potential applications in diagnostics, environmental monitoring, purity analysis and, because its assembly relies on relatively low-cost materials, they are particularly applicable for remote areas or the developing world.