Pillalamarri Srikrishnarka
Dielectica traverses through the literature on this topic – and summarizes as they appear.
Key words: Wearable electronics, Non-invasive, E-textile, hydrophobic, Health monitoring
Chennai, India: Wearable, non-invasive health monitoring sensors have an edge over conventional medical diagnostic tools. Lack of mobility, cost-ineffectiveness, a requirement of physical space and the requirement for trained personnel are some of the preliminary drawbacks of the medical diagnostic tools. With the ad of the internet of things, it has become much conducive for monitoring the necessary biomarkers on a daily basis. However, due to prolonged usage of such wearable sensors, especially on the skin, could lead to discomfort and wet-thermal management is crucial or it could lead to further health complications. Sweat consists of a vast variety of components apart from water, by non-invasively monitoring these components, could help in the overall health assessment of the health of the wearer. Fabrics are by far the most favorable for absorbing sweat, keeping the body cool and protecting one from extreme environment.
Traditional fabrics are ideal for adsorbing the sweat on the skin which helps in keeping the skin dry. However, they can transfer the moisture from the cloth to the skin once, the fabric is completely wet. Fabrics, however, can be customized based on the requirement. When I meant customization, it’s not merely changing the shape and adding colors. Fabrics’ chemical properties can be altered completely transforming the very nature of cloth. For example, we all know that natural fabrics are hydrophilic in nature, i.e., they absorb water. A single droplet of water immediately spreads on it. However, by chemical functionalization this property can be completely altered, transforming the cloth to a hydrophobic one similar to that of a lotus leaf.
He et al., of Shenzen University, China, chose natural fabric silk, then chemically treated it and transformed it into a hydrophobic cloth. [1] Subsequent exposure to oxygen plasma reverted the hydrophobic nature to the hydrophilic one. The hydrophilic part of the cloth comes in contact with the skin and the hydrophobic cloth faces the environment. By doing this, they observed that most of the sweat was absorbed by the cloth and the region where the cloth was in contact was far more uniform when compared to the untreated silk. Now, that one issue of wet-thermal management was addressed, let us think about what else we can use this hydrophobic cloth. Two silk yarns were then chosen, one was coated with conducting carbon paint and the other with Ag/AgCl paint. These two were then stitched on the hydrophilic side of the silk cloth transforming the fabric into E-fabric. Electrochemical measurement was performed using this modified cloth and presence of K+ ions, pH, uric acid, as well as glucose in sweat was measured. This E-fabric was connected to a microcontroller worn on a t-shirt and sweat analysis was performed and the concentration of these species was monitored through a mobile application.
Such E-fabrics with higher selectivity and sensitivity towards the various components of sweat could further modernize the field of wearable electronics for health monitoring, owing to its simple fabrication method.
Reference:
[1] X. He et al. Nano Lett. 2021, 21, 20, 8880–8887.
https://pubs.acs.org/doi/10.1021/acs.nanolett.1c03426)