Tear-based sensors

Tears can be used as an attractive fluid for noninvasive monitoring. Tears are a complex extracellular fluid containing proteins/peptides, electrolytes, lipids, and metabolites from lacrimal glands, ocular surface epithelial cells. Meibomian glands, goblet cells, and blood. Due to a correlation between glucose levels in tears and blood, tear-based sensors are extensively used for continuous diabetes management. 

While these studies have shown that polyaniline- and polypyrrole-coated fabrics can behave as chemi-resistive sensors, it is also expected that similar chemi-resistive behavior will be achieved using ICP monofilaments and yams, which are woven or stitched into an existing fabric. Ultimately, vapor detection fabric will need to comprise of an array of sensors with the patterned response fed into a microprocessor in order to identify and determine the concentration of the vapor. The relatively low cost of production and subsequent processing of these electrically conductive fabrics provide the opportunity for designing a textile-based electronic nose, which possess built-in massive redundancy for the sensor array so that device will still function even if there is a localized break (rip, tear hole, etc.) in the fabric network. Specifically, in case some area of the sensor system fads, there is a massive redundancy in the garment such that other areas may stdl be able to acquire the information. This will greatly increase the rehabdity of the system. 

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