Sandia-developed ElectroNeedles may give diabetes patients a way to painlessly check glucose levels
Two novel micron-sized devices recently developed by Sandia researchers could mean the elimination of blood drawing by diabetes patients to test glucose levels or by medical personnel to determine if someone is having a heart attack. Test results would be instantaneous.
The two operate similarly by penetrating painlessly into the skin. Tiny needles — arranged in varying numbers on a small patch — can measure molecules inside the body, eliminating the need to withdraw blood from a patient.
One platform is ElectroNeedles, micron-sized electrodes capable of measuring molecules such as glucose that can donate or accept electrons (redox behavior). The other is µPosts, micron-sized posts that have the potential of painlessly measuring proteins and other macromolecules, including protein markers released during a heart attack, using optical measurements. The platforms complement each other and create a diagnostic suite capable of detecting many important biological markers.
“The tiny ElectroNeedles, expected to be constructed of cheap throw-away plastic, will not only make glucose testing simple and painless, but significantly cut the diagnostics time involved in protein analysis,” says Jeb Flemming (1744), project lead. “Because the analysis is done inside the body, the need to withdraw body fluid is eliminated, and because the needles are so small the measurements are painless.”
Jeb and fellow researchers David Ingersoll (2521) and Carrie Schmidt (1763) came up with the idea for the ElectroNeedles and µPosts while working on the Laboratory Directed Research and Development (LDRD) Bio-MicroFuel Cell Grand Challenge where Jeb investigated harvesting sugars from living plants and animals. Some of that LDRD Grand Challenge money funded early ElectroNeedle and µPost work.
It wasn’t until they hired Colin Buckley (2521), a medical student from the University of New Mexico Medical School, that the team realized the magnitude of their invention. “Colin gave us a much-needed insight into the medical diagnostic field,” says Jeb.
The team quickly realized that the tips of the ElectroNeedles and µPosts could be coated with a biologically active layer capable of measuring concentrations of specific lipids, proteins, antibodies, toxins, viruses, and carbohydrates (such as glucose). Using the ElectroNeedles and rapid electrochemical methods for analysis, a measurement can be made in a matter of a few seconds. Likewise, using the µPosts to capture proteins and other non-redox behaving molecules, optical measurements can potentially be made in under a half hour.
“Multiple chemical platforms, such as µPosts, will change medical diagnostics by giving the physician a greater understanding of the health of the patient in a shorter amount of time than standard laboratory analysis used today in medicine,” Colin says.
The arrays may be configured in a variety of formats — larger or smaller to customize for given applications.
The ElectroNeedles and µPosts can be tailored in size to sample in different portions of the skin. For example, they can be made shorter to measure small-molecular-weight compounds such as glucose in the upper layer of the skin, or they can be made longer to measure larger molecules in the blood, such as Troponin I, a key protein released when a person has a heart attack.
“Today if someone goes to an emergency room with chest pains the doctor assesses the patient’s condition based upon their symptoms. In order to accurately diagnose a patient, the doctor has to take a blood sample, which is typically sent to an off-site laboratory for analysis,” Jeb says. “The person usually has to wait six hours to get confirmation on whether they have elevated Troponin I levels indicating they have had a heart attack.”
With a µPost test a doctor would know within a couple of minutes of a patient’s arrival at the emergency room if the patient has elevated Troponin I levels, as most of the diagnostics can take place inside an ambulance during a patient’s trip to the hospital.
“There would be little to no pain associated with this,” Jeb says. “The only thing the patient would feel is a slight itching.”
ElectroNeedles and µPosts now exist as a prototype and are made of Foturan®, a glass-like material. The intent is to ultimately mass-produce them in an inexpensive plastic
The devices have been used to measure glucose and Troponin I within pigskin, with the next step to test them on pigskins with blood.
The technological advances the team has made have led to several patents pending.