Smart Insulin Patch Automatically Manages Glucose Levels

A single use, removable transdermal patch bearing microneedles loaded with insulin can help monitor and manage glucose levels in diabetics, according to a new study.

Developed at the University of North Carolina (UNC, Chapel Hill, USA), the University of California, Los Angeles (UCLA; USA), and other institutions, the adhesive patch is made of glucose-responsive polymeric matrix, fabricated using photo-polymerization, which incorporates tiny microneedles (less than one mm long) that are pre-loaded with insulin. Once applied, the microneedles penetrate about one half millimeter below the skin, enough to sense blood sugar levels. In studies to test blood glucose regulation in insulin-deficient diabetic mice and mini-pigs, a one quarter-sized patch successfully controlled glucose levels for about 20 hours.

The patch works due to multiple phenylboronic acid units within the polymeric matrix that reversibly form glucose–boronate complexes that due to their increased negative charge, induce the swelling of the polymeric matrix and weaken the electrostatic interactions between the negatively charged insulin and polymers, thus promoting the rapid release of insulin. If the matrix senses glucose levels going up, the polymer is triggered to release insulin; when blood sugar eventually returns to normal, the patch’s insulin delivery also slows down. The study was published on February 3, 2020, in Nature Biomedical Engineering.

“Our main goal is to enhance health and improve the quality of life for people who have diabetes,” said senior author biomedical engineer Professor Zhen Gu, PhD, of UCLA. “This smart patch takes away the need to constantly check one’s blood sugar and then inject insulin if and when it’s needed. It mimics the regulatory function of the pancreas, but in a way that’s easy to use.”

Insulin is a peptide hormone is naturally produced by β cells of the pancreatic islets. It is important for the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood. Type 1 diabetes (T1D) occurs when a person’s body does not naturally produce insulin. Type 2 diabetes (T2D) occurs when the body does not efficiently use the insulin that is produced. In either case, a regular dosage of insulin is prescribed to manage the disease, which affects more than 400 million people worldwide.

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University of North Carolina
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