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| Taking blood smears for the detection of malaria parasites in the community. |
New way to diagnose malaria by detecting parasite
Over the past a number of decades, malaria diagnosis has changed really tiny. Following 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 illness. This method provides an correct count of how several parasites are in the blood - an critical measure of disease severity - but is not ideal due to the fact there is potential for human error. A investigation team from the Singapore-MIT Alliance for Analysis and Technology (Sensible) has now come up with a achievable option. The researchers have devised a way to use magnetic resonance relaxometry (MRR), a close cousin of magnetic resonance imaging (MRI), to detect a parasitic waste product in the blood of infected individuals. This approach could offer a a lot more dependable way to detect malaria, says Jongyoon Han, a professor of electrical engineering and biological engineering at MIT. "There is actual potential to make this into a field-deployable program, particularly because you don't require any sort of labels or dye. It really is primarily based on a naturally occurring biomarker that does not require any biochemical processing of samples" says Han, a single of the senior authors of a paper describing the approach in the Aug. 31 concern of Nature Medicine. Peter Rainer Preiser of Smart and Nanyang Technical University in Singapore is also a senior author. The paper's lead author is Weng Kung Peng, a study scientist at Smart. Hunting malaria with magnets With the standard blood-smear technique, a technician stains the blood with a reagent that dyes cell nuclei. Red blood cells don't have nuclei, so any that show up are presumed to belong to parasite cells. However, the technologies and experience necessary to identify the parasite are not constantly available in some of the regions most affected by malaria, and technicians do not usually agree in their interpretations of the smears, Han says. "There is a lot of human-to-human variation concerning what counts as infected red blood cells versus some dust particles stuck on the plate. It truly takes a lot of practice," he says. The new Wise method detects a parasitic waste solution named hemozoin. 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 - a weakly paramagnetic crystallite. Those crystals interfere with the typical magnetic spins of hydrogen atoms. When exposed to a strong magnetic field, hydrogen atoms align their spins in the very same path. When a second, smaller field perturbs the atoms, they need to all adjust their spins in synchrony - but if one more magnetic particle, such as hemozoin, is present, this synchrony is disrupted through a process named relaxation. The more magnetic particles are present, the much more rapidly the synchrony is disrupted. "What we are trying to really measure is how the hydrogen's nuclear magnetic resonance is impacted by the proximity of other magnetic particles," Han says. For this study, the researchers utilized a .five-tesla magnet, significantly much less expensive and effective than the two- or three-tesla magnets typically needed for MRI diagnostic imaging, which can cost up to $2 million. The current device prototype is small sufficient to sit on a table or lab bench, but the group is also operating on a transportable version that is about the size of a modest electronic tablet. Soon after taking a blood sample and spinning it down to concentrate the red blood cells, the sample analysis takes less than a minute. only about 10 microliters of blood is necessary, which can be obtained with a finger prick, generating the procedure minimally invasive and considerably less complicated for wellness care workers than drawing blood intravenously.  | Red blood cells from a patient infected with Plasmodium falciparum.
Credit: Osaro Erhabor |
"This system can be built at a really low cost, relative to the million-dollar MRI machines utilised in a hospital," Peng says. "Furthermore, since this approach does not rely on pricey labeling with chemical reagents, we are able to get every diagnostic test accomplished at a cost of much less than 10 cents." Tracking infection Hemozoin crystals are produced in all four stages of malaria infection, like the earliest stages, and are generated by all recognized species of the Plasmodium parasite. Also, the quantity of hemozoin can reveal how extreme the infection is, or no matter whether it is responding to treatment. "There are a lot of scenarios exactly where you want to see the quantity, rather than a yes or no answer," Han says. In this paper, the researchers showed that they could detect Plasmodium falciparum, the most unsafe form of the parasite, in blood cells grown in the lab. They also detected the parasite in red blood cells from mice infected with Plasmodium berghei. The researchers are launching a organization to make this technology accessible at an inexpensive price. The group is also running field tests in Southeast Asia and is exploring powering the device on solar energy, an crucial consideration for poor rural locations.
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