Tuesday, September 09, 2014

Scientists Use Magnetic Fields for Rapid Diagnosis of Malaria

A team of researchers from the Singapore-MIT Alliance for Research and Technology ( SMART) have come up with a fast, reliable and possible alternative for malaria diagnosis.

Their study published in the journal Nature Medicine, revealed a new method devised by scientists which uses magnetic resonance relaxometry (MRR), to detect the amount of hemozoin, a waste product of the malaria parasite released after feeding on nutrient-rich hemoglobin carried by the red blood cells.

As the parasite breaks down hemoglobin, iron get released which is used by the parasite to convert it to hemozoin, a weakly paramagnetic crystallite.

Crystals of  hemozoin interfere with the normal magnetic spins of hydrogen atoms. When exposed to a powerful magnetic field, hydrogen atoms align their spins in the same direction.  When a second, smaller field perturbs the atoms, they should all change their spins in synchrony – but if another magnetic particle, such as hemozoin, s present, this synchrony is disrupted through a process called relaxation. The more magnetic particles are present, the more quickly the synchrony is disrupted.

For the study researchers used a 0.5-tesla magnet, much less expensive and powerful than the 2- or 3-tesla magnets typically required for MRI diagnostic imaging.  The current device prototype is small enough to sit on a table or lab bench, but the team is also working on a portable version that is about the size of a small electronic tablet.

This study holds a lot of significance since over the past several decades, malaria diagnosis has changed very little. After taking a blood sample from a patient, a technician smears the blood across a glass slide, stains it with a special dye, and looks under a microscope for the Plasmodium parasite, which causes the disease.  This approach gives an accurate count of how many parasites are in the blood – an important measure of disease severity – but is not ideal because there is potential for human error.

The new technique, however, offers a more reliable way to detect malaria, said Jongyoon Han, a professor of electrical engineering and biological engineering at Massachusetts Institute of Technology (MIT).

There is real potential to make this into a field-deployable system, especially since you don’t need any kind of labels or dye. It’s based on a naturally occurring bio-marker that does not require any biochemical processing of samples, said Han, one of the senior authors of the research.


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