Device developed at UI could make HIV testing easier, faster
URBANA — Much like the blood sugar test which allows diabetics to quickly and easily monitor glucose levels, a new handheld device developed at the University of Illinois aims to quickly and accurately diagnose HIV, the virus that causes AIDS.
It's called a "microfluidic biochip" and it's smaller than our palm, about the size of a credit card. What it can do is count a specific type of white blood cells that the HIV virus works to destroy.
When people are tested for HIV, the process typically involves blood being drawn by phlebotomists in a lab or clinic. Then the blood is analyzed using special equipment called "flow cytometers," which are operated by trained individuals. Results can come back in a day or two and the cost is about $50 to $80 per test.
The microfluidic biochip test requires fewer people to be involved. And it costs a lot less — about $10 a test, estimated UI graduate student Umer Hassan.
"We are all excited about this technology and the kind of impact it will have, especially in low-resource settings," Hassan said.
In parts of sub-Saharan Africa, where there are approximately 22 million people living with HIV/AIDS, or rural parts of the United States, some patients live hours from a health clinic, said Rashid Bashir, UI professor and head of the Department of Bioengineering. His research group developed the chip.
The graduate student, Hassan, is co-author with Nicholas Watkins, a former UI graduate student now at a life sciences company, of a recent article in Science Translational Medicine about the research behind the improved biochip. Bashir, along with UI graduate students Gregory Damhorst and HengKan Ni; Awais Vaid, epidemiologist with the Champaign Urbana Public Health District; and Bill Rodriguez with Daktari Diagnostics also are authors on the paper.
The idea for the biochip stemmed from Bashir's sabbatical six years ago at Massachusetts General Hospital where he met Rodriguez, now CEO of Daktari Diagnostics, a company that licensed the first generation biochip technology.
Because of the drugs available now, HIV has become more of a chronic disease; however, there still are challenges associated with how to easily test patients, especially in places like Africa, Bashir said.
Bashir developed an earlier version of the HIV diagnostic biochip technology, which is expected to be available commercially next year. The new, or second generation technology, described in the recent paper, not only counts a specific kind of white blood cells, called CD4 cells, but also CD8 cells (which increase while HIV destroys CD4 cells) and determines the ratio between the two, Hassan said. That ratio can provide information on the strength of a person's immune system, he said.
And there's added potential.
"The newer, more improved version ... allows a path toward a complete blood count," Bashir said.
Imagine a cancer patient who has to go to the clinic or hospital to have blood drawn for a complete blood count. With this technology, one day the patient could run the test at home and submit the results to a doctor via smartphone, Hassan said. No grueling trip. No long wait for results.
The world of medicine, whether we like it or not, Bashir said, is moving away from the patient going to the lab and more toward the lab coming to the patient. Or rather, the lab going to a chip, he said.
"This technology is so easy to use," Bashir said. It could be run at home or at a pharmacy, he said.
To detect HIV, or figure the CD4 count, the process involves several steps. First the drop of blood enters the microfluidic biochip, which is about 3 by 4 centimeters. Because there are so many red blood cells in a microliter of blood (about 5 million red blood cells to approximately 800 CD4 cells), the red blood cells undergo lysing (they're broken up). Next comes what's called the quenching process, which stops the lysing (otherwise, the white blood cells would be destroyed). After that, microelectrodes count white blood cells, followed by the "capture chamber" phase where antibodies capture the CD4 cells. At the exit of the capture chamber, cells are counted again by microelectrodes.
The chip, which will be developed to be disposable, is then read in a device about the size of a purse, Hassan said.
With assistance from the Champaign Urbana Public Health District, where they obtained the blood samples, and Carle Foundation Hospital, where they ran the control samples, the researchers were able to test the chip's accuracy. They determined the chip to have a 90 percent to 95 percent accuracy rate, Hassan said.
The next phase involves developing the prototype and continuing to run samples. Their field research will shift to African countries, specifically Kenya and Uganda. Most samples obtained in the U.S. have come from patients already on HIV medicine, so their CD4 count is not as low as those in developing countries, Bashir said.
There the sample pool will be larger, from roughly 300 to 400 patients, Hassan said.
Taking into consideration work on completing the prototype and research in Africa, Hassan estimated this second-generation device could be available commercially in about three to four years.