Needle-Free Insulin Delivery: A Breakthrough in Skin Penetration
Table of Contents
For years, delivering medication through the skin has been a goal for researchers, with success limited by the size of the molecules. While small molecules like those in pain relievers, contraceptives, and nicotine patches readily penetrate the skin, larger ones – like insulin – were considered too large too overcome the skin’s natural barriers. This poses a notable challenge for the 1.8 million peopel in Germany alone who rely on daily insulin injections, a process many find unpleasant and even fear-inducing.Scientists have explored alternatives like microneedle patches, but a team led by Qiuyu Wei at Zhejiang University in China has now unveiled a possibly revolutionary approach: a novel polymer that facilitates the non-invasive delivery of insulin through the skin.
Bypassing the Skin Barrier
The key to this breakthrough lies in a polyzwitterion, scientifically named Poly[2-(N-oxid-N,N-Dimethylamino)ethylmethacrylat] (OP). This unique polymer exhibits a pH-dependent charge. It becomes positively charged in the acidic habitat of the skin’s outer layer, allowing it to interact with and penetrate the fatty acids present there, overcoming the first hurdle. As it moves deeper into the skin, into the neutral pH environment of the epidermis and dermis, OP also becomes neutral. This allows it to seamlessly interact with cell membranes and efficiently traverse these layers, ultimately reaching the bloodstream.
Crucially, OP acts as a carrier, capable of binding to and transporting other molecules. Wei’s team successfully coupled insulin to OP and tested this combination on diabetic mice and minipigs. The results were promising: the insulin-OP complex readily permeated the skin barrier and entered the bloodstream, effectively binding to insulin receptors and lowering blood sugar levels to normal ranges within one to two hours – comparable to the effects of traditional insulin injections.
Sustained Control & Minimal Side Effects
Interestingly, the insulin delivered via this method demonstrated a distinct advantage over injections.It accumulated in tissues like the liver, fatty tissue, and muscles, all vital for blood sugar regulation. This resulted in a longer-lasting effect, as observed by the researchers. Furthermore, the application proved to be remarkably safe. The animals exhibited no adverse side effects, and the skin remained healthy, showing no signs of irritation, inflammation, or cell damage even with repeated applications. The research team confirmed that repeated use caused no structural changes to the skin, maintaining the integrity of cell connections.
A Promising Future for Diabetes Treatment & Beyond
The researchers believe this revelation represents a significant step towards a needle-free future for insulin delivery, potentially liberating patients with diabetes from the necessity of subcutaneous injections. However, they emphasize the need for further research to confirm long-term safety and efficacy, and to refine dosage control for individual patients.
Beyond insulin, this technology holds potential for delivering other large-molecule therapeutic agents currently limited by their inability to penetrate the skin. If prosperous, this method could broaden the scope of transdermal drug delivery, offering a less invasive and more convenient option for a wider range of treatments.
Source: Qiuyu Wei (Zhejiang university, China) et al., Nature, https://www.nature.com/articles/s41586-025-09729-x
© wissenschaft.de – Elena Bernard
