EMORY/GEORGIA TECH (US)—A patch with hundreds of microscopic needles that dissolve into the skin could make it possible to painlessly administer vaccines—while providing improved immunization against diseases such as influenza.

Applied easily to the skin, the patches could be self-administered during pandemics, simplifying large-scale immunization programs in developing nations.

Details about the patches and immunization benefits observed in experimental mice are reported in the journal Nature Medicine. Conducted by researchers from Emory University School of Medicine and the Georgia Institute of Technology, the study is believed to be the first to evaluate the immunization benefits of dissolving microneedles.

“In this study, we have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle,” says Mark Prausnitz, an engineering professor at Georgia Tech.

Just 650 microns in length and assembled into an array of 100 needles for the mouse study, the dissolving microneedles penetrate the outer layers of skin.

Beyond their other advantages, including simple and safe disposal, the dissolving microneedles appear to provide improved immunity to influenza when compared to vaccination with hypodermic needles.

“The skin is a particularly attractive site for immunization because it contains an abundance of the types of cells that are important in generating immune responses to vaccines,” says Richard Compans, professor of microbiology and immunology at Emory.

“Another advantage of these microneedles is that the vaccine is present as a dry formulation, which will enhance its stability during distribution and storage,” says Ioanna Skountzou, an Emory assistant professor.

Pressed into the skin, the microneedles quickly dissolve in bodily fluids, leaving only the water-soluble backing. The backing can be discarded because it no longer contains any sharps.

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Pressed into the skin, the microneedles quickly dissolve in bodily fluids, leaving only the water-soluble backing. The backing can be discarded because it no longer contains any sharps. (Credit: Jeong-Woo Lee)

“We envision people getting the patch in the mail or at a pharmacy and then self administering it at home,” says Sean Sullivan, the study’s lead author from Georgia Tech.

“Because the microneedles on the patch dissolve away into the skin, there would be no dangerous sharp needles left over.”

Before dissolving microneedles can be made widely available, however, clinical studies will have to be done to assure safety and effectiveness. Other vaccine formulation techniques may also be studied, and researchers will want to better understand why vaccine delivery with dissolving microneedles has been shown to provide better protection.

The research was supported by the National Institutes of Health.

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