A new, more accurate Lyme disease test may result from a nanotechnology device developed by University of Pennsylvania researchers. The carbon nanotube technique was published in the Journal Biosensors and Bioelectronics.
Lyme disease, an infection spread by ticks carrying the bacterium Borrelia burgdorferi, is difficult to treat when it progresses to later stages. However, existing diagnostic tests for the disease are often unreliable in early stages- according to researchers, almost one of four Lyme disease patients is misdiagnosed. Current diagnostic tests for Lyme disease assess blood for antibodies against the bacteria, but these tests are typically not useful until an infected person's body has had enough time to build up antibodies.
"When you're initially infected with the Lyme disease bacterium, you don't develop antibodies for many days to a few weeks," said lead researcher A.T. Charlie Johnson, a professor of physics, in a press release.
"Many people see their physician before antibodies develop, leading to negative serological test results. And after an initial infection, you're still going to have these antibodies, so using these serological diagnostics won't make it clear if you're still infected or not after you've been treated with antibiotics."
The researchers created microscopic biological sensors for Lyme disease bacteria using carbon nanotubes- flexible, electrically conductive cylinders of linked carbon atoms. Instead of detecting antibodies, like existing tests, the nanotube sensors directly sensed the presence of proteins from the bacteria themselves.
According to the release from the University of Pennsylvania, the researchers connected Lyme disease antibodies to the surface of the nanotube sensors, which were charged to deliver electric signals whenever Lyme disease bacterial proteins attached to the antibodies. Then, they immersed the antibody-covered nanotube sensors in liquid solutions containing the target proteins.
The results showed that the nanotube sensors successfully detected minute concentrations of the Lyme disease bacterial protein.
"This sensitivity is more than sufficient to detect the Lyme disease bacterium in the blood of recently-infected patients, said Dustin Bresson, a study coauthor and assistant professor of biology, in the release, "and may be sufficient to detect the bacterium in fluids of patients that have received inadequate treatment."
With this success under its belt, the University of Pennsylvania team hopes to develop the nanotechnology technique into a rapid Lyme disease test. They hope that nanotube sensor test will provide more accurate diagnosis than existing antibody tests, even in early stages of the infection.
According to the Centers for Disease Control and Prevention (CDC), Lyme disease infects at least 25,000 per year in the United States. Early symptoms include fatigue, chills, fever, and joint aches, which progress to a "bull's-eye" rash and, in late stages, to arthritis and permanent neurological problems.
Source: Medical Daily