Development of a Conducting Polymer Wearable Device for Continuous Physiological Recording

Abstract

Physiological recording refers to the continuous or periodic measurement of physiological parameters. The long-term signal recording is facilitated by the adoption of ergonomic wearable devices including sensors. Typically, these signals are obtained non-invasively using silver/silver chloride (Ag/AgCl) electrodes and are placed on the skin. However, their performance is limited due to their inherent material mismatches with the skin, high interface impedance, discomfort and likely skin irritation due to prolonged use or sensitive skin. Despite the variety of reported tissue-mimicking materials in the literature, their mechanical properties often come at the expense of conductivity, resulting in low-quality recordings. This thesis investigates the development of a natural stretchable hydrogel infused conductive materials to be used in health monitoring wearable devices. This hydrogel is referred to as “Golde” and is fabricated using a facile fabrication approach, the “one-pot” method and is composed of sustainable and eco-friendly components including gelatin, chitosan and glycerol. To enhance the conductivity of the hydrogel various conducting materials such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), thermally reduced graphene (TRG), and MXene, are introduced. The resulting hydrogels demonstrated remarkable robustness and a unique thermo-reversible property without the addition of any crosslinking agent, this simplifies the fabrication process and ensures enhanced long-term stability. Additionally, the presented hydrogel fabrication is sustainable owing to the environmentally friendly materials and processes. Moreover, the resulting hydrogel electrodes were tested for ECG signal acquisition due to its inherent adhesiveness and skin-friendliness using two setups (with a backing material, all-flexible electrode). The hydrogel-based electrodes delivered high-quality ECG signals, boasting a superior signal-to-noise ratio (SNR) and remarkable resilience against interference and motion artifacts, compared to their commercial counterparts. Finally, further characterizations indicate that this hydrogel provides a versatile platform that could be adapted for a wide area of biomedical applications.

Date of Award	6 Dec 2023
Original language	American English
Supervisor	Anna-Maria Pappa (Supervisor)