The current method for testing for tuberculosis involves patients having to cough up fluid on command, a task that might be difficult for kids and people who have HIV/AIDS. The Stanford University-developed device has no moving parts and doesn’t need much electricity to work, which means it could be used in developing countries.
Tuberculosis bacteria affects about one-quarter of the world’s population, according to the World Health Organization. A small portion of those with the tuberculosis bacteria will become sick with tuberculosis. In 2017 alone, approximately 10 million people in the world were sick with tuberculosis. The researchers report that there are over 3 million tuberculosis cases that go undiagnosed each year.
Since tuberculosis affects a person’s lungs, patients have to cough up fluid from their lungs so doctors can test for the disease. But not everyone is able to cough up that sputum from the lungs.
The research team, led by Niaz Banaei, an associate professor of pathology and medicine, and Juan Santiago, a professor of mechanical engineering, wanted to develop a test that could search blood and urine for tuberculosis bacteria DNA, but tuberculosis typically doesn’t produce enough DNA with its proteins and other molecules. The next step was to develop a device that could separate relevant DNA bits from everything else in blood and urine.
Modern labs are able to do the processing of DNA in blood and urine, but the researchers set out to make a device that used very limited electricity and equipment to work in doctors’ offices.
The researchers figured out that they needed to get a pure sample of DNA in the most simple way. The team developed a device that builds on the fact that DNA and other molecules in blood and urine have different electric charges. When placed in an electric field, they move at different speeds.
Blood and urine can be placed in an electric field and device can use low power from a USB port to sort different molecules where the researchers can then grab the DNA and run tuberculosis bacteria tests.
The researchers have so far tested the device on eight patients and results have shown that the new test device is simpler and more reliable than previous testing methods.
The Stanford researcher now plan to optimize the test in more challenging situations and to test how the device works in various age groups and people with HIV/AIDS at different stages of infection.