Researchers Develop Needleless Glucose Monitoring Device

Richard Guy, PhD, MA

A new, non-invasive method for continuously monitoring blood sugar levels may replace the conventional pinpricking glucose monitoring, according to a novel proof-of-concept study.

“If development proceeds as we believe, this will be the first truly needle-less approach to continuous glucose monitoring, using a simple, flexible, disposable—but environmentally friendly—once-a-day device,” Richard Guy, PhD, MA, a professor of pharmaceutical sciences at the University of Bath, and a lead author of the study, told MD Magazine.

While patients with diabetes often require blood sugar monitoring throughout the day, which requires them to prick themselves to check levels before meals, after exercise, and at other intervals—up to 10 times a day for some patients. However, a survey by the American Diabetes Association showed that many, possibly even half, of patients do not actually check their glucose.

William H. Polonsky, PhD, CDE, a clinical psychologist and diabetes educator, suggests some reasons are emotional—it may make patients feel like their diabetes controls their lives, or they may feel bad about themselves if the levels aren’t where they should be. It also may make it more difficult to keep their diabetes private and invite questions from loved ones. It can be inconvenient, and sometimes even painful.

There have been previous attempts at non-invasive glucose monitoring before, but those that used transdermal attempts have required a needle prick test for calibration, and the patches themselves sometimes caused skin irritation. The researchers realized that they might be able to solve both problems if they just miniaturized the patch and targeted the measurements.

“We realized that each of these problems could be solved by miniaturization of the device and by aligning the extraction ‘pixels’ to hair follicles, the preferential pathways through which glucose is extracted,” Guy said.

In the study, the team developed an adhesive patch which can extract and measure glucose traveling across a single hair follicle. The new device works through iontophoresis—applying a local electrical current to the skin—the same method that previous attempts have utilized. The key to the new routine is the placement along a single hair follicle.

The researchers tested the prototype first on pig skin, where the device was able to accurately measure blood sugar levels that are common in patients with diabetes. Then, they tested it on 2 healthy volunteers, who showed a normal variability of blood sugar, over the course of 6 hours which included lunch and a snack.

“We think that the device will appeal not only to diabetics, but also to so-called pre-diabetics who are at risk of becoming diabetic but have not yet manifested symptoms,” Guy said. “In the long-term, a wearable such as this could become an adjunct to a healthy life-style in general.”

Now that the concept has been proven, the next step will be to conduct full-scale clinical trials to prove that the device can work over a full 24-hour day. If successful, the device could have implications for a large patient population. Additionally, the cost of the device is another important consideration for its potential for widespread production and use.

“Our design can be implemented using high-throughput fabrication techniques like screen printing, which we hope will ultimately support a disposable, widely affordable device," Adelina Ilie, PhD, another lead author and a physics professor at the University of Bath, said in a press release.

The study, “Non-invasive, transdermal, path-selective and specific glucose monitoring via a graphene-based platform,” was published in Nature Nanotechnology.