New, less invasive, technique to diagnose malaria

Written by Rebecca McCutcheon, Future Science Group

Researchers from the Singapore-MIT Alliance for Research and Technology (SMART; Singapore) have developed a new technique for more accurate diagnosis of malaria. This alternative method uses magnetic resonance relaxometry to detect a waste product from the Plasmodium parasites in the blood, as opposed to current microscopy techniques.

Jongyoon Han, a senior author on the paper published recently in Nature Medicine, commented: “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 biomarker that does not require any biochemical processing of samples.”

These are just some of the advantages of the new technique. The existing method presents a potential for human error, as a technician examines a glass slide of a specially dyed blood sample from the patient and counts the numbers of parasites present.

The detection requires expertise that is not always available and interpretation of the slides is subjective with technicians often disagreeing. “This technique could offer a more reliable way to detect malaria” Han continued, referring to the new proposed method.

In the studies described, the researchers have shown they can identify two key Plasmodium species: falciparum and berghei.

The SMART system detects the parasitic waste product hemozoin, a weakly paramagnetic crystallite produced when the parasite feeds on haemoglobin. A blood sample is first exposed to a strong magnetic field before a second smaller field is then introduced. The weakly magnetic hemozoin particles interfere with the hydrogen atoms realignment when the smaller field is introduced, and the degree of this interference can be measured.

This analysis, which is done using only a finger prick of blood, takes around a minute and is minimally invasive compared with having to take blood intravenously. Unlike hospital MRI, “this system can be built at a very low cost” said Weng Kung Peng, a SMART researcher and lead author of the paper. “This technique does not rely on expensive labelling with chemical reagents; we are able to get each diagnostic test done at a cost of less than 10 cents.”

The team currently have a desktop prototype but have plans to develop a portable version around the size of a small electronic tablet. The researchers aim to make the technology affordable and more widely available by launching a company. Further, future developments include a solar powered version for use in rural areas, for which field tests are currently being run in Southeast Asia.

Source: A new way to diagnose malaria; Peng WK, Kong TF, Ng CS et al. Micromagnetic resonance relaxometry for rapid label-free malaria diagnosis. Nat. Med. 20, 1069–1073 (2014).