Supervisors: Dr Olaf Rolinski / Dr Shareen Forbes / Prof David Birch
Alzheimer’s disease is associated with the aggregation of the small peptides beta-amyloids (A) gradually forming toxic fibrillar structures in the brain tissue of the sufferer. Although A aggregation has been widely studied, the mechanisms underlying the formations of aggregates in vivo are still poorly understood. Sporadic occurrence of Alzheimer’s implies that in addition to the typical factors determining aggregation (temperature, pH, ionic strength, presence of denaturants), other processes must contribute to the onset and progression of the disease. One of such processes seems to be glycation of A peptides, i.e. their modifications by interactions with carbohydrates. We hypothesise that determining the presence of different glycation products, leading to faster amyloidosis, may help to identify those at increased risk of developing Alzheimer’s. Our experiments will be performed in vitro and our aim is to identify photophysically different glycation products in beta-amyloids and correlate these products with the slow and high rates of formation of amyloid aggregates which will be monitored by fluorescence. We will therefore determine if the process of glycation and fluorescence operate in tandem.
Through links with Sunnergos the biotechnology business development arm of the University of Edinburgh we will liaise with a number of drug companies to open up the field of small molecule testing. We may then test if there are compounds that prevent formation of these products of glycation and consequently amyloidosis. Such studies would inform in vivo testing of these small molecules and therefore pave the way to the new therapeutics.
In this project we will apply time-resolved fluorescence spectroscopy and imaging (fluorescence lifetime imaging microscopy - FLIM) to monitor the glycation-induced misfolding and aggregation of A peptides in vitro. If a strong correlation between glycation and aggregation is found, an in vivo approach will be also developed. Intrinsic fluorescence signals from both the fluorescent amino acids and the advanced glycation end products (AGEs) are sensitive to the changes in the local environments on the nm scale. This makes the intrinsic fluorescence an ideal non-invasive method for gaining information on structural changes in the amyloid assemblies during their glycation and early stages of aggregation in different models of biological environments. In the project we aim to initially use the new techniques for time- and spectrally-resolved intrinsic fluorescence measurements to detect the smallest changes in protein conformations. After achieving μm sizes during aggregation, the amyloid fibrils will be investigated by fluorescence lifetime imaging microscopy (FLIM).
Supervisors: Dr Philip Hands / Dr Toby Hurd / Dr Ann Wheeler / Prof Baljean Dhillon
This PhD research project will develop newly-emerging tuneable and highly-customisable liquid crystal laser
sources, and apply them to the field of fluorescence-based retinal imaging, for the detection of age-related
macular degeneration and other ophthalmic diseases.
Autofluorescent (or fluorescent-tagged) biomarkers such as lipofuscin, within the retinal pigment epithelium,
can be optically probed using lasers to search for ophthalmic medical abnormalities. Despite the potential
capabilities of this technique, its clinical adoption is somewhat limited, restricted to specialist laboratories.
Each fluorescent biomarker has its own specific optical absorbance range, and so medical equipment must
compromise between detection versatility (i.e. containing multiple lasers with different wavelengths, each
targeting a different marker, and hence be large, bulky and expensive), or portability (i.e. contain only a single
laser source addressing a single fluorophore, and hence be small and portable). Compromised systems must
also be built around the availability of existing light sources, which do not cover the full colour spectrum,
resulting in poor signal strength and signal ambiguity due to overlapping absorbances between multiple
Newly-developed liquid crystal (LC) lasers use self-assembling chiral nanostructures to create tuneable laser
cavities only 10 μm thick, and when doped with organic dyes enable simple, highly efficient and customisable
laser emission over the visible spectrum (450-850 nm). They have great potential as small, low-cost,
switchable and tuneable light sources for medical imaging applications, thus eliminating the requirement to
compromise between versatility, portability and cost, and potentially enabling cheaper, smaller and more
effective diagnostics tools. Tuneable LC lasers can be designed to perfectly match the absorbance
requirements of the biomarkers, maximising detection capabilities. They also provide a simple route to
providing new modalities of detection, such as ratiometric imaging and fluorescence lifetime imaging,
through temporal control of rapidly changing pulsed wavelength patterns.
Working in collaboration with engineers, biomedical scientists, ophthalmic clinicians and a world-leading
microscopy manufacturer on a highly interdisciplinary project, the student will demonstrate a proof-ofconcept
system using LC lasers to perform clinically-relevant fluorescence imaging of the retina for disease
diagnostics. They will use cleanroom microfabrication, opto-mechanical and electro-optical approaches to
construct bespoke LC laser and microscope systems (with properties including tuneable wavelengths and
temporal control of single or multiple simultaneous beams). LC lasers will be designed to optimally probe
multiple common fluorescent retinal markers simultaneously, and their performance advantages compared
to conventional sources will be validated. Further investigations will also be made into the clinical
opportunities of techniques such as ratiometric imaging and fluorescence lifetime imaging, enabled by LC
lasers, to provide improved data to the field of point-of-care ophthalmic disease detection. Opportunities for
commercial development will also be explored, in collaboration with our industrial partners.
Supervisors: Dr Shareen Forbes / Prof Mark Bradley / Dr Marc Vendrell
In individuals with Type 1 diabetes, beta cells (within a cluster of cells termed islets) are destroyed by immune processes and individuals are left dependent on insulin injections. Islet transplantation in individuals with Type 1 diabetes stabilises blood glucose control, improves quality-of-life and can be life-saving. However, islets engraft poorly in the body and individuals rarely come off insulin injections; most recipients require islets from at least 2-3 donor pancreases which is problematic due to donor organ shortage. Strategies to increase islet engraftment, diminish inflammation post-transplant and find alternatives sources of insulin secreting cells are urgently required.
We propose to test a human beta cell line (EndoC-BH3) with a range of polymers incorporating different ligands – e.g. collagen and anti-inflammatory ligands. We will identify which polymers promote beta cell engraftment and beta cell function in vitro. Candidate polymers will then be selected, labelled with fluorescent probes (fluorophores) used to coat beta cells prior to transplantation into mice using the kidney capsule route initially and then the clinically relevant intra-hepatic route. This in vivo imaging will be undertaken at short term time points initially to allow us to determine stability, fate, function and safety of such polymer-beta cell interactions which is urgently required in this field.
Supervisors: Dr James Hopgood / Mr Damian Mole / Ms Dawn Gilles and Mr Paul Cowling / Dr Colin Campbell
Liver cancer is the second leading cause of cancer deaths worldwide in men and, the sixth in women: millions of people are affected. Liver cancer usually arises on a background of chronic liver disease, and worldwide, 80% of liver cancer cases are due to hepatitis B and C infection. Ultrasound is a widely available technique that can be used to scan the liver for tumours. Where the liver is scarred from hepatitis, or other causes, distinguishing between cancer tissue and scarring is difficult. This project will develop and refine better ways of processing ultrasound images to improve cancer detection rates.
The data analysis developed could be equally applicable to other modalities, such as optical resolution photoacoustic microscopy (OR-PAM). OR-PAM has recently been used in liver analysis, which shows strong textural structure.