Textile handicraft for equipment-free fabrication of wearable low-cost diagnostic sensors for body-fluid based pathology

We report a low-cost, rapid and single-step method for fabricating microfluidic cloth-based analytical devices (mu CADs) without involving any sophisticated instruments, simply by painting hydrophobic zones on cotton cloth using a liquid mixture primarily composed of polyurethane-based commercial wood finish. The mixture needs to be applied on cloth using a paint brush and subsequently dried in open air for only around 5 min to complete the process of hydrophobic barrier deposition. The painted regions show extreme hydrophobicity and demonstrate excellent barrier integrity and chemical inertness with a wide range of liquids, reagents, solvents and biological fluids. Channels of different designs are fabricated with sufficient dimensional reproducibility, despite adhering to manual painting step. Using this simple fabrication method, a colorimetric glucose detection assay is demonstrated on cloth-based devices, which has been found to be highly accurate as benchmarked with a laboratory-referenced biochemistry analyzer. The inherent simplicity and cost-effectiveness of this method is likely to foster sustainable growth of rural handicrafts specialized in manufacturing low-cost wearable sensors for rapid point-of-care diagnostics.