Targeting Malaria’s Achilles’ Heel, Hemozoin

A waste product from the malaria parasite provides researchers with an elegant alternative to conventional diagnosis methods.

AsianScientist (Sep. 4, 2014) – A research team from the Singapore-MIT Alliance for Research and Technology (SMART) has devised a novel method to diagnose malaria. The findings have been published in Nature Medicine.

Conventional malaria diagnosis, which has changed little over the past few decades, involves manual examination of a patient’s blood sample under a microscope. A special dye is used to identify and count the Plasmodium parasites which cause the disease. While this approach is useful in measuring the severity of malaria infection, the inherent potential for human error makes it less than ideal.

Using magnetic resonance relaxometry (MRR), a close cousin of magnetic resonance imaging (MRI), researchers were able to detect a type of parasitic waste product, known as hemozoin crystallites, in the blood of infected patients.

When the parasites infect red blood cells, they feed on the nutrient-rich hemoglobin carried by the cells. As hemoglobin breaks down, it releases iron, which can be toxic, so the parasite converts the iron into hemozoin. Hemozoin crystals are produced in all four stages of malaria infection, including the earliest stages, and are generated by all known species of the Plasmodium parasite. Hemozoin levels can also reveal how severe the malaria infection is, and whether the body is responding to treatment.

For this study, researchers took advantage of hemozoin’s paramagnetic characteristics by using magnetic resonance as a measurement tool. They were able to use tesla magnets that are less expensive—albeit also less powerful—than those usually required for MRI diagnostic imaging.

This method allowed for the detection of Plasmodium falciparum, the most dangerous form of the parasite, in blood cells grown in the lab. The scientists also detected the parasite in red blood cells from mice infected with Plasmodium berghei.

This new technique is “more sensitive, less error-prone, and requires less blood sample as compared to the standard blood-smear protocol,” says Ham Donhee, a professor of electrical engineering at Harvard University who was not part of the research team. “I think there is a strong potential here, and I look forward to its further development for reliable field deployment.”

The device prototype configured by the scientists is small enough to sit on a table or lab bench, and the team is also working on a handheld portable version. After taking a blood sample and spinning it down to concentrate the red blood cells, sample analysis with the device takes less than a minute. Only about 10 microliters of blood is required, which can be obtained with a finger prick.

“This system can be built at a very low cost, relative to the million-dollar MRI machines used in a hospital,” says lead author Professor Peng Weng Kung, a research scientist at SMART. “Furthermore, since this technique does not rely on expensive labeling with chemical reagents, we are able to get each diagnostic test done at a cost of less than 10 cents.”

The study authors are launching a company to launch this technology, with field tests ongoing in Southeast Asia.

The article can be found at: Peng et al. (2014) Micromagnetic resonance relaxometry for rapid label-free malaria diagnosis.


Source: Singapore-MIT Alliance for Research and Technology.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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