MOBILE HEALTH/FLUORESCENCE: Portable, low-cost fluorescence biosensor diagnoses Type 1 diabetes early
A portable, inexpensive, and microchip-based fluorescence biosensor could improve Type 1 diabetes diagnosis and care, and help researchers better understand the disease.1
Evidence suggests that early detection and aggressive new therapies may halt Type 1 diabetes' autoimmune attack on the pancreas and preserve some insulin-making ability. But distinguishing between Type 1 and Type 2 diabetes now requires a time-consuming, expensive test that's limited to sophisticated health-care settings. The traditional test detects the auto-antibodies using radioactive materials, takes several days, requires highly trained lab staff, and costs several hundred dollars per patient.
By contrast, the microchip, developed at the Stanford University School of Medicine (Stanford, CA), uses no radioactivity, produces results in minutes, and requires minimal training to use. Each chip, expected to cost about $20 to produce, can be used for upward of 15 tests. In addition, instead of requiring a lab-based blood draw, it can be done with blood from a finger prick.
The device relies on a fluorescence-based method, near-infrared fluorescence-enhanced (NIR-FE) detection, for detecting the antibodies. The team's innovation is that the glass plates forming the base of each microchip are coated with an array of nanoparticle-sized islands of gold, which intensify the fluorescent signal to enable reliable antibody detection.
The test was validated with blood samples from people newly diagnosed with diabetes and from people without diabetes, and compared with tests on the same samples using the older method.
In addition to people newly diagnosed with diabetes, the test may benefit people who are at risk of developing Type 1 diabetes, such as patients' close relatives—because it will allow doctors to quickly and cheaply track their auto-antibody levels before they show symptoms. Because it is so inexpensive, the test may also allow the first broad screening for diabetes auto-antibodies in the population at large.
Stanford University and the researchers have filed for a patent on the microchip, and the researchers also are working to launch a startup company to help get the method approved by the FDA and bring it to market, both in the U.S. and in parts of the world where the standard test is too expensive and difficult to use.
1. B. Zhang, R. B. Kumar, H. Dai, and B. J. Feldman, Nature Med., 20, 948–953 (2014); doi:10.1038/nm.3619.