School of Physics and Astrophysics

BioMagnetics research group

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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.

  1. Our research
  2. Projects
  3. Publications
  4. Equipment

Our research

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.

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Projects

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. 

Pure Basic Research

Small Particle Magnetism

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. 

Key Papers 

Structural and magnetic properties of nanoscale iron oxide particles synthesized in the presence of dextran or polyvinyl alcohol. J. Magn. Magn. Mater. 2001

Proposed biosensors based on time-dependent properties of magnetic fluids. J. Magn. Magn. Mater. 2001

Apparent magnetic energy-barrier distribution in horse-spleen ferritin: Evidence for multiple interacting magnetic entities per ferrihydrite nanoparticle. Phys. Rev. B 2002

A comparison of methods for the measurement of the particle-size distribution of magnetic nanoparticles. J. Appl. Crystal. 2007

Insight into microstructural and magnetic properties of flame-made γ-Fe2O3 nanoparticles. J. Mater. Chem. 2007 

Biomineralisation

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.  

Key Papers 

Iron biominerals in medicine and the environment. Coord. Chem. Rev. 1999

Characterization of dugong liver ferritin. Anal. Chim. Acta 1999

Dietary iron-loaded rat liver haemosiderin and ferritin: in situ measurement of iron core nanoparticle size and cluster structure using anomalous small-angle x-ray scattering. Phys. Med. Bio. 2009

Magneto-reception

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.   

Strategic Basic Research

Development of MRI contrast agents

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.

Key Papers 

Magnetically targeted and activated drug delivery

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.

Key Papers 

Thales: an instrument to measure the low field magnetophoretic mobility of microscopic objects. J. Phys.: Conf. Ser. 2005

Encapsulation and Sustained Release of Curcumin using Superparamagnetic Silica Reservoirs. Chem.-Eur. J. 2009

Anti-fouling magnetic nanoparticles for siRNA delivery. J. Mater. Chem. 2010

Poly(N-isopropylacrylamide)-Coated Superparamagnetic Iron Oxide Nanoparticles: Relaxometric and Fluorescence Behavior Correlate to Temperature-Dependent Aggregation. Chem. Mater. 2011

Continuously manufactured magnetic polymersomes - a versatile tool (not only) for targeted cancer therapy. Nanoscale 2013

Pathogenic iron deposits

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.

Key Papers 

Applied Research

Development of new diagnostic techniques for Schistosomiasis

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. 

Key Papers 

The iron distribution and magnetic properties of schistosome eggshells: implications for improved diagnostics. PLOS Negl. Trop. Diseases 2013

Liver fat determination using MRI

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.  

Key Papers 

Experimental Development

FerriScan® - Iron determination in hemoglobinopathies 

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.  

Key Papers 

Single spin-echo proton transverse relaxometry of iron-loaded liver. NMR Biomed. 2004

Noninvasive measurement and imaging of liver iron concentrations using proton magnetic resonance. Blood 2005

The Effect of Reducing Repetition Time TR on the Measurement of Liver R2 for the Purpose of Measuring Liver Iron Concentration. Magn. Reson. Med. 2011

Multicenter Validation of Spin-Density Projection-Assisted R2-MRI for the Non-Invasive Measurement of Liver Iron Concentration. Blood 2010

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

Malaria detection using magnetic fractionation

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.   

Key Papers 

Magnetic susceptibility of iron in malaria-infected red blood cells. Biochim. Biophys. Acta-Mole. Basis Disease 2009

A comparison of the sensitivities of detection of Plasmodium falciparum gametocytes by magnetic fractionation, thick blood film microscopy, and RT-PCR. Malaria J 2009

Short Report Quantification of Plasmodium falciparum Gametocytes by Magnetic Fractionation. Amer. J. Trop. Med. and Hyg. 2011

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Publications

Publications by members of the group are listed back to 1998.

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Equipment

Numerous pieces of equipment are owned and operated by the BioMagnetics research group.

  • SQUID Magnetometer - With a 7 Tesla solenoid and temperature inserts which allow measurements between 2K and 800K.
  • 57Fe Mossbauer Spectrometer - With a liquid helium cryostat, available for measurement of hyperfine fields of Fe-based materials.
  • Vibrating Sample Magnetometers - we have two available in the laboratory. They operate using superconducting solenoids to produce magnetising fields of 5 Tesla and 12 Tesla. Sample cryostats permit measurements of magnetic and electrical properties at temperatures ranging from 3.8K up to 1000K.
  • 10, 20, 40 and 60 MHz Bruker MiniSpec proton relaxometers with variable sample temperature control (25°C to 40°C)
  • Optical microscope with digital video capture
  • Magneto-Optic Magnetometers - Both a high speed (microsecond timescale) unit and a high stability (1000's of seconds timescale) unit with fields up to a 2.2 Tesla and temperatures from room temperature to liquid helium.
  • Radio-Frequency Sputtering System - For plasma deposition of thin films, under high vacuum conditions.
  • Pulsed Inductive Microwave Magnetometer (PIMM) - for measuring magnetic response of materials to pulsed fields on picosecond timescales

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.

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Last updated:
Monday, 26 May, 2014 4:17 PM

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