Redox regulation and homeostasis are critically important in the regulation of cell
function; however, there are significant challenges in quantitatively measuring and
monitoring intracellular redox potentials.
The work in this thesis details a novel approach to intracellular redox monitoring.
The approach is based on the use of nanosensors, which comprise molecules capable
of sensing the local redox potential, assembled on gold nanoshells. Since the Raman
spectra of the sensor molecules change depending on their oxidation state, and since
the nanoshells allow a large enhancement of the Raman scattering, intracellular
potential can be calculated by simple optical measurements. A full description of the
design, fabrication and characterisation (spectroscopic and electrochemical) of the
nanosensors is provided within.
The ability to deliver nanosensors into cells in a controllable fashion was confirmed
using electron microscopy. Results from a range of assays are also presented which
reveal that introduction of nanosensors does not result in any cytotoxicity.
Sensor utility in monitoring redox potentials as cells responded to physiological and
superphysiological oxidative and reductive stimuli was investigated. Importantly, the
capability of the nanosensors in monitoring intracellular potentials in a reversible,
non-invasive manner, and over a previously unattainable potential range, is
demonstrated