Development, Optimisation and Applications of Screen-Printed Electrochemical Sensors

Abstract

The sustainability of healthcare delivery depends on the adoption of new low-cost devices to support the transition of services from centralised generic models to home and community-based care models, through which the patient status can be monitored remotely. Easily accessible body fluids (like saliva, sweat and interstitial fluids) represent alternative sampling media to blood that in principle can be conveniently analysed through wearable sensors. For instance, continuous monitoring of pH in saliva would allow a better clinical management of pathologies that alter acid contents within the mouth. Similarly, the real-time tracking of sodium levels in sweat and other body fluids can assist clinicians in the diagnosis and treatment of Cystic Fibrosis. Furthermore, athletes could reap many benefits from an optimal strategy for personalised rehydration, which might be informed by continuously measuring the amount of minerals lost in sweat. Electrochemical sensors based on the combination of screen-printed working and solid-contact reference electrodes are versatile and low-cost tools that are effective in facing many of the challenges in current sensing technology. They can be readily adapted for the detection of several ionic species, and in this thesis, as an example, two electrochemical platforms to monitor pH in saliva and sodium in sweat are going to be presented. The final devices are minimally-invasive and wearable, with a compact format due to the integration of miniaturised solid state ion-selective and reference electrodes. The technological advancements developed for their realisation are significant contributions for the more flexible design of novel miniaturised sensors for remote monitoring in general. Future developments of this technology could be pivotal for realising devices for applications as diverse as sensors integrated into fabrics for personal health monitoring, or autonomous sensors deployed in rivers and lakes for monitoring water quality