Green and Integrated Wearable Electrochemical Sensor for Chloride Detection in Sweat

Abstract

Wearable sensors for sweat biomarkers can provide facile analyte capability and monitoring for several diseases. In this work, a green wearable sensor for sweat absorption and chloride sensing is presented. In order to produce a sustainable device, polylactic acid (PLA) was used for both the substrate and the sweat absorption pad fabrication. The sensor material for chloride detection consisted of silver-based reference, working, and counter electrodes obtained from upcycled compact discs. The PLA substrates were prepared by thermal bonding of PLA sheets obtained via a flat die extruder, prototyped in single functional layers via CO2 laser cutting, and bonded via hot-press. The effect of cold plasma treatment on the transparency and bonding strength of PLA sheets was investigated. The PLA membrane, to act as a sweat absorption pad, was directly deposited onto the membrane holder layer by means of an electrolyte-assisted electrospinning technique. The membrane adhesion capacity was investigated by indentation tests in both dry and wet modes. The integrated device made of PLA and silver-based electrodes was used to quantify chloride ions. The calibration tests revealed that the proposed sensor platform could quantify chloride ions in a sensitive and reproducible way. The chloride ions were also quantified in a real sweat sample collected from a healthy volunteer. Therefore, we demonstrated the feasibility of a green and integrated sweat sensor that can be applied directly on human skin to quantify chloride ions.

Wearable sweat chloride sensors: materials, fabrication and their applications

“…15 Multiple polymer materials such as poly(dimethylsiloxane) (PDMS), polyethylene terephthalate (PET), polylactic acid (PLA), polyimide (PI), polyvinyl chloride (PVC), poly methyl methacrylate (PMMA) and polyamide (PA) are used to fabricate wearable sensors. 16 Other substrates like paper are textiles are also commonly used to make wearable sensors. These materials are patterned using various fabrication methods such as lasers, 3D printing, photolithography and screen printing to manufacture these sensors.…”

“…These materials are patterned using various fabrication methods such as lasers, 3D printing, photolithography and screen printing to manufacture these sensors. [16][17][18][19] In this section, a brief description of commonly used substrates and the fabrication methods are summarized for wearable Cl − sensors.…”

“…Lopresti et al (2022) prepared a wearable electrochemical sensor to detect Cl − ions in sweat by patterning a PLA (0.5 mm thick) substrate using a CO 2 laser. 16 Wei et al (2023) prepared a wearable sweat patch for the detection of sweat and Cl − levels using a PET film (12 μm in thickness). The film was engraved by laser cutting as shown in Fig.…”

“…Laser cutting provides a versatile approach to create patterns and microstructures on various materials, including exible substrates. Lopresti et al (2022)prepared a wearable electrochemical sensor to detect Cl − ions in sweat by patterning a PLA (0.5 mm thick) substrate using a CO 2 laser 16. Wei et al (2023) prepared a wearable sweat patch…”

Advances in Fiber-Based Wearable Sensors for Personal Digital Health Monitoring

“…The use of electrochemical sensors to monitor biomarkers in human sweat is a common method [84][85][86]. For instance, a multifunctional textile sensor made of rGO/polyaniline (PANI) hybrid fibers can be used to monitor multiple biomarkers simultaneously [87].…”