Novel interfaces for internet of wearable electrochemical sensors

Abstract

The integration of wearable devices, the Internet of Things (IoT), and advanced sensing platforms implies a significant paradigm shift in technological innovations and human interactions. The IoT technology allows continuous monitoring in real time. Thus, Internet of Wearables has made remarkable strides, especially in the field of medical monitoring. IoT-enabled wearable systems assist in early disease detection that facilitates personalized interventions and proactive healthcare management, thereby empowering individuals to take charge of their wellbeing. Until now, physical sensors have been successfully integrated into wearable devices for physical activity monitoring. However, obtaining biochemical information poses challenges in the contexts of fabrication compatibility and shorter operation lifetimes. IoT-based electrochemical wearable sensors allow real-time acquisition of data and interpretation of biomolecular information corresponding to biomarkers, viruses, bacteria and metabolites, extending the diagnostic capabilities beyond physical activity tracking. Thus, critical heath parameters such as glucose levels, blood pressure and cardiac rhythm may be monitored by these devices regardless of location and time. This work presents versatile electrochemical sensing devices across different disciplines, including but not limited to sports, safety and wellbeing by using IoT. It also discusses the detection principles for biomarkers and biofluid monitoring, and their integration into devices and advancements in sensing interfaces.

Fig. 1. Body wearable devices: (A) voltammetric sensors: (a) as sweat patch regulating the drug methylxanthine; (b) schematic of caffeine sensing band; and (c) fentanyl detecting gloves with square-wave voltammetry. Reproduced from ref. with permission from Wiley-VCH, copyright 2018 & reproduced from ref. with permission from Elsevier, copyright 2019. (B) Another wearable dual iontophoretic biosensor based on a tattoo, to simultaneously detect glucose and sweat: (a) dual iontophoretic biosensor for ISF glucose and sweat alcohol detection on a human subject with data being transmitted wirelessly to a mobile device; (b) screen printed electrode with wireless circuit on which the iontophoretic operation takes place. Reproduced from ref. with permission from Wiley-VCH, copyright 2018. (C) Illustration of drug delivery via the iontophoretic technique: (a) and (b) showcase an integrated wristband for the detection of sweat via iontophoretic technique (sensors based on detecting cystic fibrosis electrochemically). Reproduced from ref. with permission from the National Academy of Sciences, copyright 2017. (D) (a) Biosensor as a mouthguard with wireless circuit board integrated to an amperometric genosensor for detection of UA; (b) carbon WE modified with Prussian Blue attached to Uricase via BSA for detection of UA in saliva and photos showing wireless circuits from front and back side. Reproduced from ref. with permission from Elsevier, copyright 2015. (E) (a) Schematics of a smart contact lens composed of a hybrid substrate which is embedded with stretchable conductors and functional devices to detect glucose in human tears in real-time; (b) schematics showing working of the lens by wireless transmission of power which activates the LED pixel and thus the sensor for detecting glucose. As the glucose level in the tear reaches a threshold level the LED pixel switches off. Reproduced from ref. with permission from the American Association for the Advancement of Science, copyright 2018.

Fig. 2. (A) A flexible film electrode with nano-Au/CNTs/PDMS for the onsite analysis of hydrogen peroxide production from HUVECs in the stretched state. (B) Graphical representation of (A) Ni SACs/NC composite synthesis and (B) the sensor to sense NO and HUVECs culture. Reproduced from ref. with permission from Springer Nature Limited, copyright 2020.

Fig. 3. Illustration of (A) a wearable band-based sensor to detect on-body sweat. Reproduced from ref. with permission from Elsevier, copyright 2022. Wearable levodopa sweat sensors with construction details. (B) Levodopa sensor. (C) Functionalized electrodes. Reproduced from ref. with permission from the American Chemical Society, copyright 2019. Mechanism of uric acid sensing. (D) Real-time uric acid detection in sweat with high-purine food intake. (E) Sensing process of the uric acid sensor. Reproduced from ref. with permission from Elsevier, copyright 2022.