Title: Embroidered Electrochemical Sensors on Gauze for Rapid Quantification of Wound Biomarkers
Authors: Xiyuan Liu, Peter B. Lillehoj
Publication Info: https://doi.org/10.1016/j.bios.2017.06.053
Chronic skin wounds, or wounds that do not heal in the typical stages and time frames characteristic of an acute wound, are an epidemic estimated to directly affect ~2% of the entire human population at some point in their lifetime. A wound becomes chronic when the body’s ability to deal with the damage is overwhelmed by factors such as poor circulation, neuropathy, stress, repeated trauma, illness, bacterial colonization, or ischemia. Beyond the obvious discomfort, chronic wounds can result in the loss of limb(s), widespread infection, and even death.
The best cure for chronic wounds is prevention; and early detection of an impeded healing process is key. Wounds have been found to exhibit certain physical and biological markers (e.g. temperature, pH, or bacterial metabolites) that signal issues with healing and the potential for a wound becoming chronic. Uric acid is one specific marker which has been found to correlate with the existence of bacterial infections in wounds, which left untreated, can become chronic.
Thus the ability to detect elevated levels of uric acid as early as possible would enable easier and more successful wound treatment. This work provides a promising solution to this problem in the form of a “smart” uric acid-sensing band-aid. Utilizing common textile threads and a residential embroidery machine, standard medical gauze wrap is transformed into a real-time health monitor as illustrated in Figure 1.
Standard polyester textile threads are first made conductive by soaking them in a carbon-based ink. The threads are then patterned into electrodes which can be utilized as an electrochemical sensor. This work reports that even in the complex matrix characteristic of wounds, this sensor exhibits sensitivity and selectivity for the electrochemical oxidation of uric acid (oxidation reaction shown below) – thus able to forewarn patients and medical staff of potential impediments to wound healing at an early stage.
While the success of this work is exciting on its own merits, the potential this technology demonstrates is even more exciting. In addition to successfully monitoring for various medical maladies, electrochemical based sensors are also economically viable solutions. Requiring only a low-capacity disposable battery and some basic electronic components, large scale production of smart sensors, such as demonstrated in this work, could be readily produced for on the order of $1 and thus conducive to world-wide proliferation.