Help for Hide and HeartOctober 1, 2005 By: Stephanie vL Henkel, Sensors Sensors
Part of the misery of being diabetic is having to prick your finger or arm for glucose-level testing. And haste prevents waste when it comes to diagnosing a heart attack. Sandia researchers led by Jeb Flemming are developing diagnostic tools—ElectroNeedles and μPosts—that could benefit both diabetics and heart patients. Other members of the research team include Sandia's David Ingersoll and Carrie Schmidt, and Colin Buckley, a medical student at the University of New Mexico Medical School.
ElectroNeedles (photo, with needles in package center) are micron-sized electrodes capable of measuring glucose and other molecules that can either donate or accept electrons (redox behavior). Configured in arrays, the needles penetrate the skin painlessly and take a glucose measurement inside the body, without drawing blood. Rapid electrochemical analytical methods produce readings in seconds.
μPosts take advantage of optical technology to measure proteins and other macromolecules, including the elevated troponin I levels associated with certain types of heart attack. The procedure is painless, and the analytical results are available in <30 min. after the patient's arrival in the ER because most of the diagnostics can be handled in the ambulance en route. Compare this scenario with conventional diagnostic techniques that require drawing a blood sample and sending it to the lab, a protocol that can mean six hours of waiting.
The MicroNeedle and μPost platforms are mutually complementary. The tips of both devices are coated with a biologically active layer that measures concentrations of specific lipids, proteins, antibodies, toxins, viruses, and carbohydrates (e.g., glucose). Their size can be custom-tailored for different areas of the patient's skin—shorter for diabetes testing and longer for larger molecules in the blood such as troponin I.
The prototype ElectroNeedles and μPosts are fabricated of Foturan, a glass-like material. The market versions are expected to be made of an inexpensive, disposable plastic. Thus far they have been tested for measuring glucose and troponin I in pig skin, with additional testing with blood to follow.
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