Researchers at the Stanford University School of Medicine (Stanford, CA) have developed a fluorescence- and microchip-based biosensor device for diagnosing Type 1 diabetes that could improve patient care worldwide and help researchers better understand the disease. What's more, the device is inexpensive and portable.
Related: The many approaches and applications of biosensing
The biosensor employs nanotechnology to detect Type 1 diabetes outside hospital settings. Its handheld microchips distinguish between the two main forms of diabetes mellitus, which are both characterized by high blood-sugar levels but have different causes and treatments. Until now, making the distinction has required a slow, expensive test available only in sophisticated health-care settings.
"With the new test, not only do we anticipate being able to diagnose diabetes more efficiently and more broadly, we will also understand diabetes better—both the natural history and how new therapies impact the body," says Brian Feldman, MD, Ph.D., assistant professor of pediatric endocrinology and the Bechtel Endowed Faculty Scholar in Pediatric Translational Medicine.
A growing body of evidence suggests that rapid detection of, and aggressive new therapies for, Type 1 diabetes benefit patients in the long run, possibly halting the autoimmune attack on the pancreas and preserving some of the body's ability to make insulin.
The old, slow test detected the auto-antibodies using radioactive materials, took several days, could only be performed by highly trained lab staff, and cost several hundred dollars per patient. In contrast, the microchip 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. The microchip also uses a much smaller volume of blood than the older test; instead of requiring a lab-based blood draw, it can be done with blood from a finger prick.
The microchip 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. Both groups had the old test and the microchip-based test performed on their blood.
In addition to new diabetics, people who are at risk of developing Type 1 diabetes, such patients' close relatives, also may benefit from the test 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 old test is too expensive and difficult to use.
Full details of the work appear in the journal Nature Medicine; for more information, please visit http://dx.doi.org/10.1038/nm.3619.
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