People with diabetes need to carefully control their glucose and insulin levels. An ideal device to help them would link glucose detection and insulin administration without the patient needing to be involved. A team led by Zhen Gu of the University of California, Los Angeles, has developed glucose-responsive insulin patches that could be a step in the right direction (Nat. Biomed. Eng. 2020, DOI: 10.1038/s41551-019-0508-y).
The quarter-sized patch consists of an array of insulin-containing polymeric microneedles. The needles are made of a mixture of polymers, including one with glucose-binding phenylboronic acid. When the acid binds glucose, the polymer develops a negative charge. As the density of negative charges increases, the electrostatic interactions between the insulin and the polymeric matrix weaken, and insulin is released as a result. The ratio of components in the polymer matrix can adjust the rate of insulin release from the microneedles.
The researchers tested the patches by using them to treat mice and minipigs with diabetes. In 25 kg minipigs, the patches maintained glucose levels in the normal range for more than 20 h under normal feeding conditions. The patches can be personalized by changing their size or adjusting the ratio of components in the polymer mixture.
“Microneedle patch technology is gaining traction as a way to administer drugs and vaccines without the need for injection,” says Mark R. Prausnitz of the Georgia Institute of Technology, who is also developing microneedle devices. “This study takes the technology a step further by designing the microneedles to release insulin in response to blood glucose levels.”