Development of self-powered and non-invasive diagnostic devices

  • Carla Gonzalez Solino

Student thesis: Doctoral ThesisPhD


Current healthcare systems are failing to cope with a growing and ever more chronically ill population. Point-of-care (POC) technologies can revolutionise healthcare by offering personalised and rapid health monitoring. Amongst the POC devices available, continuous glucose monitoring systems (CGMs) have improved the life of diabetic patients, allowing them to monitor their glucose levels to prevent severe health complications. Unfortunately, CGMs are still powered by standard batteries which are difficult to miniaturise; this makes the devices bulky and not comfortable to patients. As an alternative, glucose fuel cells (GFCs) offer the opportunity to develop self-powered glucose sensors for continuous monitoring. GFCs couple the oxidation of glucose to the reduction of oxygen, using either metal or biological catalysts, to generate electricity. In this context, this thesis aims to develop a miniaturised fuel cell for the self-powered detection of glucose in interstitial fluid (IF). Two different catalysts, metals and enzymes, were tested for the development of sensitive and specific electrodes towards glucose and oxygen. Electrodes modified with highly porous gold (hPG) films showed good sensitivity towards glucose, 42.5 µA mM-1 cm-2, at low overpotentials. The high activity of these electrodes decreased in the presence of common interferences. Enzymes were also immobilised on hPG films to increase the specificity of these electrodes. Metal-based fuel cells showed higher power output (0.22 µW in 6 mM glucose) compared to the enzymatic fuel cells, which can be attributed to the lower catalytic density of enzymes. The power output was successfully scaled-up by stacking four metal-based fuel cells in parallel, achieved using printed circuit board (PCB) technology. The stack showed a linear response to glucose from 300 µM to 9 mM, which covers the hypo and hyperglycaemic concentrations in IF, and successfully charged a capacitor of 470 µF in 6 mM glucose. Finally, polypyrrole (PPy) nanostructures were developed to obtain high surface area electrodes as an alternative to hPG films for the covalent immobilisation of glucose oxidase. These PPy-based electrodes showed high specificity to glucose, with a linear response up to 10 mM. However, these electrodes were not suitable for application in fuel cells due to the high overpotential. Overall, these results demonstrate the selfpowered detection of glucose using PCB-based glucose fuel cells and open exciting opportunities for the development of miniaturised wearable sensors.
Date of Award22 Jul 2020
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorMirella Di Lorenzo (Supervisor), Stefan Bagby (Supervisor) & Christopher Pudney (Supervisor)

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