All PEDOT:PSS Fully-Textile Wearable Chemical Sensors

Organic ElectroChemical Transistors (OECTs) are promising electronic platforms to realize chemical sensors since they can provide intrinsic signal amplification without the need of a freestanding reference electrode, they can operate at low power (&lt; 100 μW) and can be easily miniaturized and adapted to non-flat, flexible and textile substrates. In addition, providing high sensitivity together with biocompatibility and low-cost, they could be proposed as analytical tools for the reliable detection of a wide range of low concentration analytes even in biological fluids such as sweat and wound exudate.<br/>All poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) OECTs can be used as chemical sensors for the detection of redox analytes that are oxidized at PEDOT:PSS, such as ascorbic acid, dopamine, adrenaline or uric acid [1].<br/>On the other hand, the selectivity issue must be addressed to allow the widespread use in real-life applications, through a proper functionalization of the gate electrode with molecules able to selectively interact with the target analyte [2, 3]. In this regard, pH or chloride sensors have been described by our research group, entrapping iridium oxide or silver/silver chloride nanoparticles on the PEDOT polymer, thus developing two terminal sensors able to work without an external gate electrode.<br/>One of the most appealing features of OECT chemical sensors is the possibility of realizing the whole device in a fully-textile form using easy scalable procedures thus allowing the development of a compact, lightweight, cost-effective, and easy to wear platform for monitoring healthcare and sport activities in real-time.<br/>This contribution describes two examples of fully-textile wearable chemical sensors based on PEDOT:PSS OECTs. The first one is a multi-thread biosensing platform that can detect chloride ions (Cl⁻) concentration and pH level simultaneously without interference. The textile sensors are simple threads, based on natural and synthetic fibers that show excellent sensitivity, reproducibility, selectivity, long term stability and the ability to work with small volumes of solution. The performance of the developed textile devices is demonstrated in artificial human perspiration to perform on-demand and point-of-care epidermal fluids analysis.<br/>The second example of application is a fully-textile smart bandage for pH [4] and uric acid detection, to be applied for hard-to-heal wounds (i.e. severe and/or chronic) monitoring, where it is critical to constantly evaluate the healing stages and the overall wound condition.<br/>The use of special medical-grade textile materials provides a passive sampling system, which enables the continuous, real-time and non-invasive analysis of wound fluid.<br/>REFERENCES<br/>[1] I. Gualandi, M. Marzocchi, E. Scavetta, M. Calienni, A. Bonfiglio, B. Fraboni, <i>J. Mater. Chem. B</i> <b>2015</b>, <i>3</i>, 6753.<br/>[2] I. Gualandi, M. Tessarolo, F. Mariani, D. Arcangeli, L. Possanzini, D. Tonelli, B. Fraboni, E. Scavetta, <i>Sensors</i> <b>2020</b>, <i>20</i>, 1.<br/>[3] I.Gualandi, M. Tessarolo, F. Mariani, T. Cramer, D. Tonelli, E. Scavetta, B. Fraboni, <i>Sens. Actuators B</i> <b>2018</b>, <i>273</i>, 834.<br/>[4] F. Mariani, M. Serafini, I. Gualandi, D. Arcangeli, F. Decataldo, L. Possanzini, M. Tessarolo, D. Tonelli, B. Fraboni, E. Scavetta, <i>ACS Sens.</i> <b>2021</b>, 6, 2366.