Researchers bypass blood work, favoring lasers to detect malaria

Using the same tech a destroyer uses to detect a submarine, a new diagnostic tool listens for the sound of popping vapor nanobubbles -- a telltale sign that malaria parasites are dining.

Elizabeth Armstrong Moore
Elizabeth Armstrong Moore is based in Portland, Oregon, and has written for Wired, The Christian Science Monitor, and public radio. Her semi-obscure hobbies include climbing, billiards, board games that take up a lot of space, and piano.
Elizabeth Armstrong Moore
3 min read
The laser pulse creates a vapor nanobubble in a malaria-infected cell to quickly and noninvasively diagnose the disease. E. Lukianova-Hleb/Rice University

Diagnosing malaria can be a bit of a pain, especially when trying to test in remote parts of the world where such tests are most needed. For one, it requires a standard blood smear test with the right chemical reagents and a high-quality microscope. It also should be done by a lab technician with proper training, and each test takes 15 minutes and costs roughly $1. Oh -- and the tests spoil in hot climates if not properly stored.

Now, thanks to researchers at Rice University, a new test that uses laser pulses -- and requires no blood draws, microscopes, or technicians -- is in the works. Better yet, the device they created for the test allows one person to be screened every 20 seconds (a 45-fold improvement over the 15-minute tests) for half the price (50 cents).

If you're reading this from the comfort of a largely malaria-free pocket of the world and wondering why you should care, consider this: The disease is one of the world's deadliest, infecting hundreds of millions of people a year and claiming the lives of more than 600,000. Still don't care? There's also this: Year in and year out, most of the dead are children.

While the Rice team's discovery isn't a cure for a disease that is becoming increasingly resistant to treatments, it could dramatically improve early diagnosis and outcomes.

Writing in a journal called Proceedings of the National Academy of Sciences, the researchers said that their approach detected malaria in a preclinical trial on mice where only one red blood cell in a million was infected, and there were no false positives.

This was possible because a laser pulse that lasts less than a second is able to heat hemozoin -- the iron crystal byproduct of hemoglobin that is found in malaria parasites feasting on red blood cells, but not found in normal blood cells. Because the hemozoin crystals absorb the energy from the laser pulse, they heat up enough to create transient vapor nanobubbles that pop. That pop produces a ten-millionth-of-a-second acoustic signature that is the telltale sign that malaria parasites are lurking within. The device can hear that acoustic signature using the same technology a destroyer uses to detect a submarine, only on a far smaller scale.

Dubbed "vapor nanobubble technology," a laser scanner can detect these bursting bubbles with a fiber-optic probe attached to the skin (think finger or ear lobe) in mere seconds when malaria is present. So while blood is very much involved in this test, it need not be extracted from the patient. And because the vapor bubbles are only generated by hemozoin, which is only present in infected cells, the approach did not generate a single false-positive result.

The scanner was invented by Dmitro Lapotko, a physicist, astronomer, biochemist, and cellular biologist who studied laser weapons (in his spare time?) in Belarus before heading to Rice. The device is rugged enough to operate in the dustiest of environments and needs only a car battery (i.e. one that is portable) for power.

"The vapor nanobubble technology for malaria detection is distinct from all previous diagnostic approaches," said study co-author David Sullivan, a malaria clinician at Malaria Research Institute at Johns Hopkins University, in the school news release. "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."

Lapotko said Houston will be home to the first clinical trials on malaria-infected humans in a matter of weeks.