Researchers from the KTH Royal Institute of Technology in Stockholm have developed a patch that combines stainless steel microneedles and a soft polymer base. The team’s work was published this month in PLOS ONE.
“To the best of our knowledge, flexible and stretchable patches with arrays of sharp and stiff microneedles have not been demonstrated to date,” lead researcher Frank Niklaus said in prepared remarks.
The soft material of the patch makes it comfortable, according to the team, while the stiff microneedles penetrate the upper layer of the skin and avoid touching the nerves. The researchers suggested that the patch could be used in a variety of ways – delivering drugs, measuring physiological signs in fitness monitoring devices, glucose monitors, or even cosmetic skin treatments.
Niklaus said that most microneedle patches are “monoliths”, meaning the needle and the base of the patch are made of the same material. Microneedles need to be stiff in order to penetrate the skin, but a hard base is uncomfortable to wear.
The team tested 2 versions of the patch. The patch with a base made out of molded thiol-ene-epoxy-based thermoset film was more flexible than the other patch and conformed well to the skin surface. In a 30 minute test, all 50 microneedles successfully penetrated the skin.
Co-author Niclas Roxhed noted that a comfortable microneedle patch could help those who have chronic illnesses and need constant care. “The chronically ill would not have to take daily injections,” Roxhed said.
He also explained that the patch offers a hygienic benefit, since millions of people die every year from improper handling of needles, according to the World Health Organization. “Since the patch does not enter the bloodstream, there is less risk of spreading infections,” Roxhed said.