School of Physics and Astrophysics

Projects

Some projects we have undertaken in the Biomagnetics research group:

Small particle Magnetism

Ferritin is an iron storage protein in the biology that sequesters Iron(III) oxyhydroxide. The protein limits the growth of the iron oxyhydroxide complex to sizes of 8nm or less, maintaining the iron in a single domain superparamagnetic state. We seek to understand how the structure and composition of a superparamagnetic particle affects its magnetic properties, and how the particle size distribution of synthetic analogues may be controlled.

Biomineralization in Iron-Overload disease

Diseases such as hereditary haemochromatosis and congenital anemias can lead to the accumulation of high concentrations of iron in the tissues of the body over a lifetime. This group has a track record in the characterisation of the biomineralization of different forms of iron, whether as free iron, in soluble proteins such as ferritins or in insoluble haemosiderin. Characterising the differences in the chemical and structural composition of iron oxides within the body gives insight into the mechanisms of treatment for the iron overload diseases. Variations are seen both between individuals across populations and within organs of the same individual.

MRI in Iron Overload Disease

This research group is a pioneer into the research on non-invasive measurement of tissue iron concentration by magnetic resonance imaging (MRI). Present techniques for quantifying tissue iron by MRI rely on the paramagnetic character of the iron stores. The pioneering work led to the non-invasive liver iron measurement technique that is now commercially available through Resonance Health Ltd which is marketed as FerriScanĀ®. Research has progressed to include other iron loaded organs, such as the spleen, heart and brain. Research efforts also target the sensitivity and specificity of the different iron quantification techniques.

These key papers tell the story of liver iron concentration measurement:

1. Development of a technique in the lab 
    T. G. St. Pierre, P. R. Clark and W. Chua-anusorn, NMR in biomedicine 17, 446-458 (2004).

2. Testing/calibrating the technique in the clinical environment
    T. G. St. Pierre, P. R. Clark, W. Chua-anusorn, A. J. Fleming, G. P. Jeffrey, J. K. Olynyk, P. Pootrakul, E. Robins and R. Lindeman, Blood. 105 (2), 855-861 (2005).

3. Improving the performance of the technique
    H. L. Pavitt, Y. Aydinok, A. El-Beshlawy, S. Bayraktaroglu, A. S. Ibrahim, M. M. Hamdy, W. J. Pang, C. Sharples and T. G. St Pierre, Magnetic Resonance in Medicine 65 (5), 1346-1351 (2011).  

4. Validating the accuracy of the technique in the clinical setting
    T. G. St Pierre, A. El-Beshlawy, M. Elalfy, A. Al Jefri, K. Al Zir, S. Daar, D. Habr, U. Kriemler-Krahn and A. Taher, Magnetic Resonance in Medicine, n/a-n/a (2013).

5. Assessing the impact of the technique in clinical practice
    G. C. Brown, W. N. Patton, H. E. Tapp, D. J. Taylor and T. G. St Pierre, Internal Medicine Journal 42 (9), 990-996 (2012).

Ferrofluids

The synthesis, characterisation and manipulation of ferrofluids which are stable in a variety of solvents poses a challenging research problem. This group has an established track record in the field and considers biological applications of the fluids, such as: biosensing based on the magneto-hydrodynamic properties of the fluids; and guided repair of detached retina.

Organic-Inorganic Nanoscale Particles

The synthesis and characterisation ofnanoparticles with organic and inorganic phases is an active area of research. Two areas of advancement have been in: synthesising and characterising ferrimagnetic nanoparticles; and the synthesis of low-moment superparamagnetic rod-like particles, up to several hundred nanometres long but only 6nm wide. Consideration is given to the formation of large assemblies of superparamagnetic single domain particles.

Magnetic Bacteria

Populations of magnetotactic bacteria can be found in the oxic-anoxic transition layer of some water bodies, where they use the earth's magnetic field to orient their movements. Biomineralised iron oxide sensor chains permit the bacteria to sense the earth's magnetic field, and manipulation of the local magnetic field can manipulate the orientations along which the bacteria swim. There are many different varieties of magnetotactic bacteria and considerable variation in the arrangement of the sensing apparatus.

Schistosoma

The Schistosoma parasites damage organs, impair growth and cause neural disease among their hosts. Diagnosis of an infection is tyoically by screening the faeces of the infected for the eggs of the parasite. The eggs are formed by an interesting biomineralisation process which lends itself to magnetic detection and characterisation.

Malaria

When a malaria parasite feeds on and digests hemoglobin it produces a damaging, iron based waste product called hematin. The hematin is converted by the parasite into an inert, acicular shaped iron product called hemozoin. The synthesis of hemozoin is an interesting target for drug therapies for treating malaria. The magnetic characterisation of hemozoin allows for the development of new diagnostic tools and provides a better understanding of the cariation in hemozoin synthesis amongst different strains of the parasite.

 

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Last updated:
Wednesday, 27 November, 2013 10:25 AM

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