A nanocomposite textile fiber electrode functionalized with uricase has been integrated in a wearable platform for uric acid monitoring. Uric acid is a metabolic product of purines which exerts role in tissue healing by initiating the inflammatory process.¹ Throughout the healing process, the uric acid levels are elevated in the wound fluids with relative concentrations correlating with wound chronicity.^{2, 3} Though sensors embedded in the point of care devices allowed rapid wound diagnostics, still there are no wearable technology for continuous monitoring. In this work, a three-dimensional high aspect ratio nanocomposite textile based electrode was investigated. The unique structure of the electrode provided larger surface area for enzyme immobilization, and an excellent platform for electron transfer from enzymatic reaction. The enzyme immobilization was carried out by entrapping uricase in a cationic polymer on the fiber surface. The uricase reaction mechanism involves the hydrolysis of uric acid in presence of oxygen, and release of hydrogen peroxide as a byproduct. The redox electron shuttle, ferrocene carboxylic acid (FCA) enabled electron transfer between the byproduct of uric acid and the fiber, generating the signal. The voltammogram result shows a stable electrochemical response at an onset potential of 0.25V with a limiting current of 0.6 µA. The 0.25V onset potential is ideal for any hydrogen peroxide measurement without interference from oxygen reduction reaction. This functionalized fiber electrode enabled the possibility of textile based wearable sensor for monitoring wound chronicity.

References

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2. T. R. Dargaville, B. L. Farrugia, J. A. Broadbent, S. Pace, Z. Upton, and N. H. Voelcker, Biosens. Bioelectron. 41, 30–42 (2013).
3. M. L. Fernandez, Z. Upton, H. Edwards, K. Finlayson, and G. K. Shooter, Int. Wound J., 9, 139–49 (2012).