The aim of this thesis was to develop novel carbon-based biosensors and sensors for
real-time metabolite and drug detection, to provide the next generation of medical devices
which can give clinicians relevant chemical information in real-time at the patient bedside.
An autocalibration system was developed using LabSmith programmable components
to give precise fluid delivery and excellent temporal control of multiple liquid streams. This
enables a 5-point calibration to be carried out using two solutions in 12 minutes. Systems
using chitosan, poly(ethylene glycol)diglycidyl ether hydrogel, electrodeposition and selfassembly
to immobilise enzymes on a combined needle electrode surface were studied and
their performances were investigated using a microfluidic platform. The autocalibration
system was combined with the graphene oxide-based biosensors in a microchip coupled
with a microdialysis probe and was examined as a proof-of-concept clinical on-line analysis
system. A reduced graphene oxide-based sensor was fabricated using a combined needle
electrode for on-line neurotransmitter detection of dopamine. Its performance was compared
with that of a platinum electrode.
A microfluidic sensor based on a carbon nanotube-epoxy composite was fabricated to
detect the presence of carboplatin (anti-cancer drug) in healthy tissue in real time during
chemotherapy. Detection of carboplatin was carried out using differential pulse voltammetry
firstly in a beaker, in which carbon nanotube-epoxy composite electrodes performed better
than glassy carbon electrodes for oxidation of free purine bases and than DNA-modified carbon
nanotube-epoxy composite sensors for detection of carboplatin. Carboplatin detection
was then performed in a microfluidic platform. The methodology for on-line carboplatin
detection was optimised in terms of the analysis time and for the repeated determination of
carboplatin using the same electrode. Microdialysis and microfluidic techniques have been
combined to give a proof-of-concept system real-time carboplatin detection using the carbon
nanotube-epoxy composite sensors.