Is it Sci-Fi? New diagnostic tool may soon eliminate guesswork and save lives.

When the ambulance screeches to a halt and emergency medical technicians rush to aid an unresponsive patient, there can be a lot of guesswork. Heart failure? Drug overdose? Diabetic shock? The appropriate treatment may not come for hours, until after the ambulance returns to the hospital and doctors receive the blood test results that determine the diagnosis.

But emergency medical technicians may soon have a new tool that could provide a diagnosis while en route to the emergency room. Scientists at Sandia National Laboratories (Sandia) in Albuquerque, New Mexico, are collaborating with companies on a fingernail-sized patch that could perform those blood tests immediately, when the ambulance reaches the scene. The patch bristles with tiny needles that feed test results into a handheld device, enabling emergency room doctors to have the treatment ready and waiting when the patient arrives.

Called Electroneedles, the painless jabs could be a boon for diabetics, who must prick their fingers for blood samples at least three times a day. Testing cholesterol could become a matter of minutes. Doctors in developing countries could diagnose patients even when they lack access to a medical lab.

The tiny needles, about the width of a human hair, reach only half a millimeter into the skin. They do not need to reach a vein. They analyze the fluid that bathes cells. Since nerve endings are deeper than half a millimeter, the prick doesn’t even hurt. “They go into the skin very easily,” said Jeb Flemming, chief engineering officer at Albuquerque-based Life BioScience, Inc., one of two companies that are commercializing the technology. Multiple needles in an array form a single Velcro-like patch that could perform dozens of tests in minutes. No comparable technology can do so many tests at once.

Electroneedles grew out of a Sandia Grand Challenge—a collaborative project to develop fuel cells that harvest energy from living organisms. The ultimate goal was a matchbox-sized fuel cell that soldiers could use in the field to collect energy from plant sugar (or glucose) to power equipment.

Flemming, a design engineer on the project, wondered if the same needles that collect the glucose energy could reach fluids in patients and allow medical diagnostics. A glucose meter was an obvious possibility.

“If you’re a diabetic, your glucose level is a topic of enduring importance to you,” said Steve Casalnuovo, manager of the Biosensor and Nanomaterials Department at Sandia. Diabetics routinely check their blood sugar levels to make sure it’s not too high or too low.

The scientists tested their idea using skin from pigs’ ears and a glucose solution as a stand-in for human tissue. The order for pigs’ ears from the local butcher shop “was one of the strangest purchase requests I’ve ever signed,” Casalnuovo said.

Since glucose can swap electrons with another molecule, glucose oxidase, it didn’t need to be sucked through the needle. Instead, the scientists filled the needle with metal and affixed glucose oxidase to the tip. When the oxidase encountered the glucose, the electrons changed hands and sent an electrical signal through the metal that the scientists picked up on the other end.

In addition to glucose meters, scientists at Sandia, Life BioScience, and New Mexico Biotech, Inc., are expanding the technology to detect proteins, carbohydrates, toxins and pathogens—all without a single blood draw. Since only a subset of molecules is electrically active, researchers are developing compounds that will emit light when they meet their target. The light signal will be transmitted to the detector through a transparent needle. “It allows a little tiny window into the human body,” Flemming said. These light-based devices are called microposts, or μposts.

The first commercial units will likely cost thousands of dollars, but the hope is to eventually offer a ballpoint pen–sized glucose meter that will cost $1 per test, making it competitive with other devices already on the market. Commercial products could be on the market in three or four years.

Electroneedles and μposts could someday join stethoscopes and blood pressure cuffs as fixtures in physicians’ offices. “I think it has a lot of potential,” said Dr. Dominic Raj, a kidney specialist at the University of New Mexico in Albuquerque. The ability to monitor patients without waiting an hour or more for lab results will “not only save time, but save lives.”