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Our first paper of 2015 investigated a novel technique for detecting magnetic particles, which would be significant for bio-medical applications:

Interaction effects enhancing magnetic particle detection based on magneto-relaxometry.

O.Laslett, S.Ruta, J.Barker, R.W.Chantrell, G.Friedman, O.Hovorka

Applied Physics Letters 106, 012407 (2015)

But why is it important to detect particles? And how will improving particle detection improve bio-medicine?

Magnetic nanoparticles

A typical magnet, such as a bar magnet or horse-shoe magnet, is in the realm of macro-scale objects. These are objects that we can measure with a standard ruler and we are familiar with how macro-scale magnets generally behave from personal experience - remember those fun physics lessons in school.

Nano-scale magnets are tiny and measure just 0.0000000001m across. These magnetic nanoparticles behave differently from what we expect in normal sized magnets and some of this fascinating behaviour can actually be useful for applications in bio-medicine, such as: scanning patients, delivering drugs, and potentially eliminating tumours.

When magnetic particles group together they form nanoparticle clusters. Different cluster shapes cause different magnetic behaviour and, since these clusters are so difficult to see, we need new scientific methods to be able to detect this behaviour inside a complex environment, such as a human body.

particle cluster examples

Magneto-relaxometry

Magneto-relaxometry is a technique that uses external magnetic fields and sensors - just like MRI scanners - to determine the behaviour of magnetic clusters. In our recent paper, we investigated how these measurements change with different particle cluster shapes.

S5 particle data S4 particle data

For example, look at these two figures on the right, the horizontal lines give an idea of the information that we can get from magneto-relaxometry measurements. Let's start with the black lines, we might not be surprised that the information looks quite similar for these two very similar magnetic particle clusters shapes (called S4 and S5).

However, we found that if we rotate the magnetic field and then take the measurement again, we get different data (the blue lines) and a difference appears between the two. In other words, by rotating the magnetic field we can differentiate between - that is, we can detect - similarly shaped magnetic particle clusters.

What does this mean for bio-medicine?

The ability to detect different particle clusters is an essential rung on the ladder to engineering magnetic nanotechnology for exciting new medical techniques.

For example, magnetic particle based imaging could be used as a replacement in situations where MRI and CT scans are potentially harmful to a patient. And some studies have even demonstrated how magnetic nanotechnology might be used to destroy tumours.

Computational engineering techniques, like those we are developing at the University of Southampton, will be essential if we are to take full advantage of nanotechnology in bio-medicine.

More from the Computational Engineering and Design Group.


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