Skin Patch with Microneedles May Provide Improved Alternative for Various Applications

Researchers have developed flexible and stretchable patches with rigid stainless steel microneedles for transdermal biointerfacing. Such microneedle patches could enable more comfortable yet effective delivery of drugs, extraction of physiological signals for fitness monitoring devices, extracting body fluids for real-time monitoring of glucose, pH level and other diagnostic markers, as well as skin treatments in cosmetics and bioelectric treatments.

Designers of such patches must balance the need for flexible, comfortable-to-wear material with effective microneedle penetration of the skin. A team of researchers from KTH Royal Institute of Technology (Stockholm, Sweden) may have cracked the problem. They have now reported successful initial testing of their microneedle patch. The soft polymer-based material made it comfortable to wear, while the stiff stainless steel needles ensured reliable skin penetration. Unlike epidermal patches, microneedles penetrate the upper layer of the skin, just enough to avoid touching the nerves.

“To the best of our knowledge, flexible and stretchable patches with arrays of sharp and stiff microneedles have not been demonstrated to date,” said Frank Niklaus, professor at KTH. He added that practically all microneedle arrays being tested today are “monoliths” in that the needles and their supporting base are made of the same, often hard and stiff, material. While that allows the microneedles to penetrate the skin, they are uncomfortable to wear. On the other hand, if the whole array is made from softer materials, they may fit more comfortably, but soft needles are less reliable for penetrating the skin.

A successful microneedle product could have major implications for health care. For example, “the chronically ill would not have to take daily injections,” said co-author Niclas Roxhed, a research leader at KTH. Microneedles also offer a hygiene benefit: the World Health Organization (WHO) estimates that about 1.3 million people die each year due to improper handling of needles – “Since the patch does not enter the bloodstream, there is less risk of spreading infections,” said Dr. Roxhed.

The study, by Rajabi M et al, was published December 9, 2016, in the journal PLOS One.

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KTH Royal Institute of Technology