Researchers have developed a novel method for delivering insulin through the skin, potentially eliminating the need for injections. A new polymer designed to permeate skin layers has demonstrated rapid blood glucose normalization in mice and mini pigs, comparable to traditional insulin injections. This breakthrough, detailed in a study published November 19 in Nature, could revolutionize diabetes management by making insulin delivery as simple as applying a patch.
The Challenge of Transdermal Insulin Delivery
For years, scientists have sought effective ways to deliver drugs—especially large molecules like insulin—through the skin. The skin’s natural barrier prevents many substances from passing through, and insulin can’t be taken orally because the digestive system breaks it down. Existing methods to enhance skin permeability, such as microneedles or chemical permeation enhancers, carry risks of infection or skin damage.
How the New Polymer Works
The Zhejiang University team, led by bioengineer Youqing Shen, engineered a polymer that exploits the skin’s natural pH gradient. Skin acidity increases with depth. The polymer is initially positively charged, binding to fatty acids in the outermost skin layers (pH 4-5). As it moves deeper into the skin (pH around 7), the polymer becomes neutral, releasing from the fatty acids and diffusing through tissue.
“The polymer works as a locomotive, with insulin as cargo,” explains Shen.
The polymer was chemically bonded to insulin, allowing it to traverse the skin and reach glucose-regulating tissues like the liver. Imaging confirmed that the combined molecule successfully permeates through skin into the bloodstream.
Results in Animal Models
In diabetic mice and mini pigs—whose skin closely resembles human skin—the polymer-insulin compound lowered blood glucose to normal levels within one to two hours, matching the speed of injections. Crucially, the effects lasted for 12 hours, significantly longer than the four-hour duration of traditional insulin delivery. No side effects were observed in the animal models.
Next Steps and Broader Implications
While the polymer has shown no immediate toxicity in animal studies, long-term safety must be rigorously tested in humans. Researchers are also refining dosage control to avoid dangerous blood glucose drops. The team is expanding this technology to other medications, including semaglutide (the active ingredient in Ozempic), with promising early results.
According to chemical engineer Robert Langer of MIT, human trials will be critical for evaluating both effectiveness and long-term safety. The development marks a significant step toward more comfortable and accessible diabetes treatment.
This technology could reshape how millions manage diabetes, moving beyond painful and inconvenient injections towards a simpler, patch-based solution.
