The BioMagnetics Group investigates the role of physics and magnetism in biology and medicine and works to develop magnetic and nano-based technologies for biomedical applications. We are a dynamic, interdisciplinary research group, equipped with state of the art magnetic measurement facilities and a modern wet lab.
Under the guidance of Professor Tim St Pierre, the members of the group work on a diverse range of topics including iron-overload disorders, magnetic nanoparticles and magnetotactic bacteria. In recent years an increasing level of international interest within the field has resulted in collaborations with institutions both within Australia and overseas. With this continued growth it it seems likely that there will be a bright and exciting future ahead for research within this field.
The BioMagnetics Research Group carries out research on naturally occurring magnetic materials in biological systems and on the development of novel physical methods for their characterization, measurement, detection, and imaging. The Group also is developing magnetic nanoparticle systems and complementary instrumentation for biomedical and medical applications.Back to top
The BioMagnetics Group undertakes a variety of research programs from pure basic research to experimental and commercial development. Some examples of our research projects are listed below.
As magnetic particles become small, approaching 10 nm, a number of changes occur to the properties these materials exhibit in bulk form. There are changes to coercivity mechanisms, magnetisation values and their time dependent properties. New properties such as superparamagnetism appear and it is possible to observe dipolar and exchange interactions within and between particles. The BioMagnetics group undertakes a range of research into small particle magnetism to better understand how the structure of the particles leads to different magnetic properties.
Iron is critical to nearly all forms of life, but it can catalyse damaging free radical reactions in its free form. Soluble iron is also relatively scarce in the environment and so living things must develop ways to capture and safely store iron. In animals, iron is stored as an iron oxyhydroxide complex within a protein cage called ferritin. The BioMagnetics Group conducts research into how different animals store and use iron in the body. Some of the examples of iron biomineralisation we have studied include marine molluscs (chitons and limpets), which use iron oxides as a hard cutting edge for their teeth, while magnetotactic bacteria use magnetite crystals to provide a sense of direction that gives them an evolutionary advantage over their competitors.
It has been shown that a number of animals possess the ability to navigate using the earth’s magnetic field. In order to do so, these animals must have the ability to sense the strength and/or direction of the local magnetic field. A number of potential magneto-receptors have been postulated, but conclusive proof of their existence has not yet been shown. We work with biologists and microscopists in trying to detect and identify magneto-receptors based on iron based particles and compounds.
In order to improve the effectiveness of medical imaging, or to enhance the visualization of specific components in a living body, it is often necessary to administer chemical compounds, known as contrast agents or media, so that the contrast between different tissues (e.g. healthy against diseased) can be increased. The BioMagnetics Group works on the development and characterisation of novel contrast agents based on superparamagnetic nanoparticles of iron oxide coated with polymer surfactants to improve the biocompatibility and provide targeted biodistribution.
One of the most exciting goals in nanotechnology research is the development of techniques for the delivery of drugs to a specific target and the release of those drugs through an activation signal. Magnetic nanocomposites provide a potential vehicle to achieve both these goals. Magnetic particles can be moved by the application of magnetic fields and field gradients through a process known as magnetophoretic motion. In addition, if exposed to an alternating magnetic field the energy released from the magnetic particles can be sufficient to change the magnetic nanocomposite and release an encapsulated drug. We are interested in understanding the mechanisms of both magnetophoresis and activated drug release in order to design better nanocomposites and the equipment to both target and release drugs.
The human body has no efficient mechanism to excrete iron and hence iron levels in the body are largely maintained by control of iron absorption from the diet. However, if the control of iron absorption is defective or if iron is directly administered through supplements or ongoing blood transfusions, then iron levels can increase beyond the limit of the body’s natural iron storage mechanisms. If this happens then it is possible that the excess iron can be deposited in the body in pathogenic forms leading to a range of negative effects. The BioMagnetics Group is interested in understanding the formation and deposition of pathogenic iron deposits their quantitative determination and methods for their removal.
Schistosoma parasites damage organs, impair growth and cause neural disease among their hosts. Diagnosis of an infection is typically by screening the faeces of the infected person for the eggs of the parasite. The eggs are formed by an interesting biomineralisation process which lends itself to magnetic detection and characterisation.
Around 50% of colorectal cancer (CRC) patients develop secondary cancers, typically in the liver. Liver surgery is the treatment of choice, but chemotherapy that is often administered prior to surgery can lead to the development of fatty liver. Patients with moderate to high levels of liver fat having major liver surgery have an increased risk of death (up to 3 times), more post-operative complications of greater severity and hospital costs up to 70% higher compared to patients with normal levels of liver fat. A reliable liver fat measurement for screening liver resection patients would lead to better-informed surgical planning decisions that could result in more patients becoming eligible for surgery and potentially reduce the rate of post-operative complications and associated costs. Our group has recently developed a highly sensitive and specific, non-invasive, MRI-based approach for measuring liver fat (FDA approval received December 2013) and is researching the application of this technique prior to liver surgery.
The BioMagnetics Group is a pioneer in the non-invasive measurement of liver iron concentrations 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 of this group led to a non-invasive liver iron measurement technique that is now commercially available through Resonance Health Ltd and is marketed as FerriScan®. Research has progressed to include other iron loaded organs, such as the spleen, heart and brain.
Spin density projection-assisted R2 magnetic resonance imaging of the liver in the management of body iron stores in patients receiving multiple red blood cell transfusions: an audit and retrospective study in South Australia. Intern. Med. J. 2012
When a malaria parasite feeds on and digests haemoglobin it produces an iron based waste product called hemozoin. Although only weakly magnetic, the hemozoin makes late stage parasites sufficiently magnetic that they can be magnetically separated from blood using a technique known as magnetic fractionation. We have shown that magnetic fractionation can be used as a highly sensitive and specific diagnostic technique for the presence of gametocytes, the form of the malaria parasite that circulate in the blood and responsible for the transmission of the disease. This technique has similar sensitivity to DNA based techniques, but at a fraction of their cost and can be easily carried out in the field with minimal laboratory equipment. The technique is presently undergoing field trials in Papua New Guinea as part of an assessment of different drug therapies.
Publications by members of the group are listed back to 1998.
Numerous pieces of equipment are owned and operated by the BioMagnetics research group.
Members of the group have access to other analytical equipment, including XRD, ICP-MS and electron and magnetic force microscopes (through the Centre for Microscopy, Characterisation and Analysis) for materials characterisation.