A team of New Zealand scientists who specialize in the development of needle-free jet injectors for drug delivery have done a 180˚ on their technology, modifying it to extract rather than inject.
Jet injection has been the subject of years of research in the Auckland Bioengineering Institute (ABI) at the University of Auckland. Researchers at the institute even developed the world’s first jet injection device that uses electric motors to pressurize the drug being delivered, allowing for more precise control compared with spring-actuated jet injectors.
Now, they have shown the technology can also be used to extract blood from under the surface of the skin. By piercing the skin with a small volume of harmless saline solution, the scientists demonstrated they could release enough blood for a glucose concentration measurement.
This needle-free technology could be a game-changer for diabetic individuals who are used to measuring their blood sugar by “pricking” their fingertips multiple times a day. It’s an effective method that draws little blood, but diabetics still experience finger pain, skin damage, bruising and risk of infection.
The study, published in the Journal of Diabetes Science and Technology, involved 20 healthy participants. The researchers pricked four fingers of each participant with a standard needle, as well as jet injection through three differently shaped and sized nozzles.
“These nozzles were designed to mimic the wound left from a lancet prick, in the anticipation that it might release blood in a way similar to a lancet prick,” said Jiali Xu, lead author of the study.
The study showed that was exactly what happened, with some nozzle shapes performing better than others. For instance, a slot-shaped nozzle released more blood than a circle-shaped one.
Most of the different jet injection nozzles were generally perceived as no more painful than a standard lancet, and in some cases, less so. To minimize biased, during the pricking, study participants were placed behind an opaque barrier that prevented them from seeing the procedure, but still allowed communication with the practitioner. Participants were asked about pain at the time of the procedure, as well as 24 hours later.
“Diesel mechanics have known for years that you should never put your finger in front of a fuel injector because it will inject fuel into your finger,” said Andrew Taberner, head of the Bioinstrumentation Lab at ABI. “They found this out the hard way. We’re taking advantage of what diesel mechanics discovered accidentally years ago, with a very small amount of harmless liquid, to deliberately release blood.”
The researchers are now investigating if they can use jet injection not only to release blood, but to extract fluid as well. This would allow for the design of an even smaller nozzle.
Ultimately, Xu said she hopes to design a single lancet-free reversible technology that will allow for both blood sampling and insulin delivery based on glucose measurement in one device.
“I hope this research will contribute to that, and improvement in human healthcare, especially in the management of diabetes,” concluded Xu.