Bursting Malaria's Bubble: Vapor Nanobubble Technology Delivers Rapid and Accurate Diagnosis
by Vivian Liang
Let's talk about malaria. It's a scourge upon many countries, predominantly in Sub-Saharan Africa and India. According to the World Health Organization (WHO), in 2010, malaria affected 219 million individuals worldwide, and it caused 660,000 fatalities — 91% of which occurred in Africa, and 86% of which were children. The most vulnerable groups include children, pregnant women, and people with compromised immunity. The risk of a malaria co-infection with HIV/AIDS or tuberculosis is especially a cause for concern.
Malaria is a severe global public health problem that imposes a financial burden to individuals, families, and governments. Costs to individuals and their families include expensive treatments and preventative measures, lost days of work and school, and potential burial expenses. Costs to governments include maintenance of health facilities, public interventions (like spraying insecticides and distributing mosquito nets), education, and research. The World Bank estimates that $12 billion per year is spent on malaria in Africa. These costs hinder the economic growth of nations and are a huge burden for developing countries.
A rapid and accurate diagnosis is a crucial factor in controlling malaria. According to the WHO, “access to diagnostic testing and treatment should be seen not only as a component of malaria control but as a fundamental right of all populations at risk.” In response to this need, scientists at Rice University have developed "vapor nanobubble" technology, a non-invasive way to detect low levels of malaria infection through the skin accurately and in mere seconds with a laser scanner.
The Vapor nanobubble technology requires an individual to place a finger on a laser device. A laser pulse is shown through the skin, and malarial parasites absorb a speciﬁc wavelength of light from the laser pulse. In response, the parasite literally explodes.
The laser is trained to focus on particles of hemozoin, which are iron nanocrystals produced by malarial parasites and not found in normal red blood cells. Hemozoin is a breakdown product formed from the digestion of blood by the parasite. When hemozoin particles are heated by the laser, they create tiny bubbles in infected cells. When the tiny bubbles burst, they produce a unique acoustic signature, which scientists can hear, see, and count. This method is extremely accurate, delivering zero false-positives (individuals that test positive for but do not have the condition) during trials.
The vapor nanobubbles are generated on demand and only by hemozoin nanocrystals, so the test is highly speciﬁc. It also delivers reliable early diagnosis of malaria, as it can also detect very low levels of infection. This technology is so sensitive that it can detect the presence of a few infected cells in a million normal cells. The results are delivered in mere seconds.
The traditional methods of diagnosis like the “blood smear“ test involve drawing blood, reagents, trained technicians to interpret samples, and expensive equipment. These are often unavailable in low-resource clinics in developing countries.
Malaria antigen testing is the most common method of diagnosing malaria in most countries. Rapid diagnostic tests (RDT) such as Paracheck are inexpensive and about as reliable as using a microscope in a blood smear test. The Paracheck device works like a pregnancy test: basically, it is a dipstick kit that uses reagents to produce a band to indicate whether or not the malaria parasite is present in a sample. However, this method still requires drawing blood. It can also still produce false positives at a rate of three percent.
The innovative vapor nanobubble technology helps to solve the current challenges in diagnosing malaria in the ﬁeld. “The vapor nanobubble technology for malaria detection is distinct from all previous diagnostic approaches,” said David Sullivan, M.D., a malaria clinician and researcher at Malaria Research Institute at Johns Hopkins University. “The vapor nanobubble transdermal detection method adds a new dimension to malaria diagnostics, and it has the potential to support rapid, high-throughput and highly sensitive diagnosis and screening by nonmedical personnel under ﬁeld conditions.
Siamak Malek, M.D., an internist at UPMC explains: “Sensitivity is important in that it tells you what percentage of people with the disease will be identified as infected by the test. This is important because you do not want to miss infected people and not treat them. The false-positive rate is particularly important because false-positives waste money on treatment meds.”
This technology comes in the form of a portable battery-powered device, but it is an expensive piece of equipment, costing between $10,000 to $20,000 to manufacture just one device. However, each device is capable of screening more than 200,000 people per year. Therefore, the cost of analysis becomes less than 50 cents per patient. Furthermore, volunteers can operate it, which saves valuable time and money for specialists.
The vapor nanobubble technology provides the invaluable advantages of speed, accuracy, reliability, portability, and convenience in diagnosing malaria. However, malaria is considered a disease of poverty. Proponents must consider if poor countries in affected areas can afford enough devices that it would make a difference, as well as the feasibility of this endeavor. This is new technology, and its acquisition remains to be seen. Tests like Paracheck are manufactured in developing countries, which promotes self-sufficiency. Some big questions include whether or not the laser technology will be patented and if it will also promote self-sufficiency.
Foreseeably, this technology will be brought to the attention of world leaders and put on the docket for discussions of a global initiative. Perhaps this technology will become part of the President’s Malaria Initiative (PMI), which was launched in 2005. PMI is a 5-year, $1.2 billion expansion of U.S. Government to provide malaria and poverty relief to Africa. Current interventions include insecticide-treated mosquito nets, indoor residual spraying with insecticides, intermittent preventive treatment for pregnant women, and prompt use of artemisinin-based combination therapies for those who have been diagnosed with malaria. Perhaps transdermal detection of malaria with vapor nanobubble technology has a place in the President’s Malaria Initiative. In any case, malaria, it’s about time your bubble got burst!