Nanowire device may help tackle malaria drug resistance
Malaria treatment could be revolutionised by a smartphone-sized nanotech diagnostic device that can tell from a drop of blood whether or not a particular treatment is likely to be effective, say its developers.
One of the major challenges that malaria poses to science is the disease-causing parasite's ability to resist treatment.
"The malaria parasite seems to be able to evolve," says Sanjeev Krishna, leader of the Nanomal Consortium led by St. George's at the University of London, which is developing the diagnostic with a €5.2 million (around US$6.8 million) grant from the EU's Seventh Framework Programme for Research.
- The Nanomal device uses nanotechnology to identify the specific parasite causing malaria infection
- No bigger than a smartphone, the device can also tell if a particular drug is going to be ineffective
- The prototype device will enter field trials within a year
There are therefore concerns that current front-line therapies, based on WHO-recommended artemisinin combination therapies, could soon become ineffective. Resistance to artemisinin has emerged in South-East Asia, and there are hints that it may soon emerge in Sub-Saharan Africa.
"Even with the earlier drugs that came into use, resistance started to be a problem very soon," Krishna says.
The Nanomal device responds to this problem by not only detecting malaria, but also identifying which of the various forms of the parasite the patient has.
"All you need is a finger-prick of blood," explains Krishna. "The device can diagnose which of the five known types of malaria is affecting the patient. For example, if the malaria is caused by Plasmodium falciparum it is more likely to be drug resistant."
And thanks to a technology called 'nanowire', the device is capable of doing much more.
"It extracts the [parasite] DNA from the blood and analyses it to tell if a particular drug, say chloroquine, is going to be ineffective. This way, doctors can immediately go for a more effective treatment," Krishna says.
Jonathan O'Halloran, chief scientific officer at QuantuMDx, one of the consortium partners, explains that nanowires are transistors in which the flow of current from one point to another is regulated by a third point called a 'gate'.
Specific DNA markers are associated with certain mutations that cause the malaria pathogen to be resistant to anti-malarial therapies.
If the target DNA marker is present in the sample, it will bind to the nanowire and act as a gate, causing changes in the electricity flow that can be measured and recognised by the device. It takes only few minutes to run the test and, once on the market, the device should cost no more than a smartphone, the developers say.
"Since it is going to be portable, this could go to villages, hospitals, everywhere you have malaria," Krishna adds.
But the device is still in the prototype stage and the team hopes to test it in the field within a year.
Colin Sutherland, a researcher at the Malaria Centre of the London School of Hygiene and Tropical Medicine, who is not involved with the device, says the concept is "very exciting" and could work.
"If we had it 20 years ago, we could have saved a lot of lives that were lost because of the resistance to the drug chloroquine," he says.
But Sutherland adds that the platform will need to be made flexible to incorporate newly discovered markers for resistance to new drugs.
Krishna is confident the device will be able to do that. "The tool is very responsive to incorporation of new markers as and when they are identified," he says. "However, there are already many markers that indicate drug resistance in antimalarial combination therapies, so there is plenty to go on as the work continues to fill in missing pieces in a complex jigsaw."