http://www.digitaljournal.com/tech-and-science/science/responsive-pain-free-skin-patch-for-diabetes/article/511217

Skin patch responds to sugar levels for diabetes care

Posted Jan 2, 2018 by Tim Sandle
A pain-free skin patch, which responds to sugar levels, has been developed for the management of type 2 diabetes. The patch, which has been tested out in rodents, continues to work for several days at a time.
An ultrathin  electronic patch as flexible as skin  applied to the wrist for Electromyography (EMG) ...
An ultrathin, electronic patch as flexible as skin, applied to the wrist for Electromyography (EMG) and other medical measurements.
John Rogers/Handout Photo
Scientists at the U.S. National Institute of Biomedical Imaging and Bioengineering have produced a especially formulated patch of dissolvable microneedles designed for the treatment of type 2 diabetes. The patch contains a biochemical formula of mineralized compounds. These compounds react to blood chemistry and function so they can manage glucose automatically.
The patch has been tested out in a proof-of-concept study carried out using mice. In tests the researchers discovered that the chemicals can interact in the bloodstream in order to regulate blood sugar, with the patch working for several days at a time.
Ky to the function of the patch is alginate (salts of alginic acid); this material is a 'gum-like' substance derived from a type of brown algae. The alginate is mixed with chemical agents and the mixture poured into a microneedle. The microneedles form the patch. Alginate is capable of poking at the outer layer of the skin, able to inject the compound but without the patient feeling as if an injection is taking place.
For the diabetes tests, exendin-4 (a molecule that reacts in response to food intake) and glucose oxidase were added to a patch and the patch tested out using mice. A patch around half an inch square was shown to effectively control blood sugar levels in mice for seven days.
According to lead researcher, Dr. Richard Leapman: "This experimental approach could be a way to take advantage of the fact that persons with type 2 diabetes can still produce some insulin."
Leapman adds: "A weekly microneedle patch application would also be less complicated and painful than routines that require frequent blood testing."
The functionality of the patch has been described in the journal Nature Communications. The peer-reviewed paper is titled "Microneedle-array patches loaded with dual mineralized protein/peptide particles for type 2 diabetes therapy."