Needle-free glucose monitoring technology comes closer to reality for people with diabetes

The needle-free technology that allows people with diabetes to measure their blood sugar levels without having to insert a needle into their fingertips, has been procured akin to reality by researchers at the Auckland Institute of Bioengineering (ABI), University of Auckland, New Zealand.

Researchers have turned their attention to needle-free jet injection, an emerging but well-developed technique in which drug is delivered directly in high-velocity narrow jets of fluid. In a study published in Journal of Diabetes Science and TechnologyLed by ABI researchers Jiali Xu and James McKeage, the researchers show for the first time that a jet injector can also be used to collect blood samples from humans — that is, releasing enough blood for glucose sampling, without needles.

People with diabetes usually need to measure their blood glucose concentrations several times each day. They do this by pricking their fingers with a needle to release a drop of blood. The glucose meter then indicates how much insulin a person needs to maintain blood sugar.

Fingertips are the preferred site for blood sampling because they have a high density of blood vessels. But fingertips are sensitive, too, and the pain, skin damage, bruising, and risk of infection from regular “pricks” have fueled efforts to develop needle-free methods of screening blood for people with diabetes.

Jet injection has been the subject of years of research by the ABI Bioinstrumentation Lab at ABI, University of Auckland, which includes developing jet syringes to deliver drugs such as insulin and nicotine and as a local anesthetic for dental treatment. He showed that this technique could also be used to penetrate the skin with a small amount of harmless saline, and this would release enough blood into the blood to measure glucose concentration – that is, for extraction rather than injection.

The study involved 20 healthy participants, each of whom volunteered four fingertips, who each received a prick with a needle (a standard needle) and a jet injection through three nozzles of different shapes and sizes. “These are designed to mimic a wound from a prick prick, with the hope that it will release blood in a similar way to a needle prick,” says Ms. Xu.

The study showed that it did, with some nozzle shapes performing better than others — for example, a “slit”-shaped nozzle released more blood than a circular nozzle. Most of the various jet-injection nozzles were generally perceived to be no more painful than a regular lancet and, in some cases, less painful: participants were blinded by an opaque barrier that prevented them from seeing the procedure but allowed them to communicate with the practitioner. They were also asked to complete a questionnaire 24 hours later to reassess the level of pain, swelling or bruising.

“When you know that no device will ever scratch your skin, you can speculate that people will find jet injections more acceptable,” says Professor Andrew Taberner, head of the ABI’s Biodevices Laboratory and Ms. Xu’s supervisor. “But we don’t have evidence to support that. That was not part of this study. We were first trying to see if it worked, and it did.”

He was pleased, but not surprised. “Diesel mechanics knew years ago that you should never put your finger in front of the fuel injector, because it would pump fuel into your finger. They figured it out the hard way. But we take advantage of what diesel mechanics accidentally discovered years ago, with a very small amount of harmless fluid, to intentionally release blood “.

The team is now looking into whether they can use the jet injection not just to excrete blood, but to suck it up, to extract fluid. This will allow for a smaller nozzle design. They have the technology, having developed the world’s first jet-injector device that uses electric motors to compress medicine – this allows for more precise control than the more common spring-powered jet injector.

“Our technology has the ability to deliver and pull liquids,” says Dr. Taberner. “No other jet drop technology has that ability.”

Research into needle-free syringes is a long game, as is the potential commercialization of the technology he says, but he believes Ms Xu’s research will contribute to the ultimate goal, which is to develop a single, reversible, pricking-free technique that will allow this. Both blood sampling and insulin delivery based on glucose measurement in a single device. “I hope this research will contribute to that, and to improving human health care, particularly in the management of diabetes,” says Ms Xu.