Thread-based multiplexed sensor patch for real-time sweat monitoring

Abstract

Sensor platforms that exploit the fibrous textile threads as substrates offer great promise since they can be directly sewn, woven or stitched on to any clothing. They can also be placed directly in intimate contact with the skin. In this work, we present a threadbased sensing platform in the form of a multiplexed sensing patch for continuous simultaneous on-skin monitoring of sweat. The patch performs real-time, on-body measurements of important biomarkers present in sweat such as electrolytes (sodium and ammonium ions), metabolites (lactate) and acidity (pH). Flexible threads coated with conductive inks were used as sensing electrodes. Selective potentiometric detection of electrolytes and pH was made possible through ion-selective membrane deposition and pH-sensitive polyaniline coating on threads, respectively. An amperometric enzymatic sensing scheme with lactate oxidase was used for the detection of lactate. An array of the thread sensors is integrated onto a patch with connectivity to a miniaturized circuit module containing a potentiostat, microprocessor and wireless circuitry for wireless smartphone readout. Extensive in vitro validation and an in vivo human pilot study involving a maximal exertion test show the promise of this platform for real-time physiological monitoring of human performance/fitness under stress, as well as diagnostic monitoring through sweat analysis.

Textile Chemical Sensors Based on Conductive Polymers for the Analysis of Sweat

“…Additionally, Terse-Thakoor et al [ 121 ] has reported a thread-based multiplex sensor patch for real-time sweat monitoring ( Figure 7 D i). In particular, such kinds of fibrous textile threads could be conveniently integrated in fabric and adhesive patches to perform on-body and real-time tracking of essential biomarkers present in human sweat, such as sodium and ammonium ions, lactate, and pH.…”

“…potentiometric response to sodium additions and iii. Chronoamperometric signal of lactate using filter paper soaked in proper analyte solutions [ 121 ].…”

Thread-based wearable devices

“…29 In another work, multiplexed sweat sensing threads were integrated into a commercial bandage as shown in Figure 5c. 57 Apart from sweat biomarkers, the perspiration level is another important indicator of one's physical status and comfort level. Conductive threads were packed inside a cotton cover to sample sweat where the change in resistivity was measured as a function of perspiration level (Figure 5d).…”

“…© 2016 Royal Society of Chemistry. (c) Fabrication of thread-based patch for multiplexed sodium, ammonium, pH, and lactate sensing 57. (d) Thread-based sensor for continuous perspiration level monitoring 58.…”

Finger Sweat Analysis Enables Short Interval Metabolic Biomonitoring in Humans

“…28 Real-time monitoring of biomarkers was demonstrated with wearable sweat sensors for uric acid and tyrosine, 29 interleukin-6 and cortisol 30 or electrolytes such as sodium and ammonium ions and lactate. 31…”