More than 387 million people are affected by diabetes worldwide, and that number is expected to grow to 592 million by the year 2035. Patients with diabetes must control their blood sugar by regularly pricking their finger and giving themselves insulin shots. The procedure is painful and imprecise – injecting the wrong amount of insulin can lead to serious complications, and in some cases, coma and death. Thanks to a new smart insulin patch, developed by researchers at the University of North Carolina and NC State, these painful injections might just be a thing of the past. The patch – a thin square about the size of a penny – is covered with more than one hundred tiny needles, each about the size of an eyelash. These “micro-needles” are packed with microscopic storage units for insulin and glucose-sensing enzymes that rapidly release their cargo when blood sugar levels get too high. The study, published in the Proceedings of the National Academy of Sciences, found that the new, painless patch could lower blood glucose in a mouse model of type 1 diabetes for up to nine hours. More pre-clinical tests and subsequent clinical trials in humans will be required before the patch can be administered to patients, but the approach shows great promise. The smart insulin patch works fast, is easy to use, and is made from nontoxic, bio-compatible materials. The whole system can be personalized to account for a diabetic’s weight and sensitivity to insulin. Researchers have tried to remove the potential for human error by creating “closed-loop systems” that directly connect the devices that track blood sugar and administer insulin. However, these approaches involve mechanical sensors and pumps, with needle-tipped catheters that have to be stuck under the skin and replaced every few days. Instead of inventing another completely man made system, the researchers chose to emulate the body’s natural insulin generators known as beta cells. These versatile cells act both as factories and warehouses, making and storing insulin in tiny sacs called vesicles. They also behave like alarm call centers, sensing increases in blood sugar levels and signaling the release of insulin into the bloodstream. While additional testing and studies are necessary before the smart insulin patch can be sold on the market, the future looks much brighter for individuals suffering from diabetes.