A few drops of water can make drug-delivering patches melt away from the skin.
The patches hold rows of tiny spikes, or microneedles, that researchers can load with medicine or vaccines. When pressed onto the skin, the spikes painlessly dig in and then dissolve to deliver their cargo (SN: 8/14/10, p. 9).
But when scientists peel the patches away, sometimes the spikes pull up too — like arm hair stuck to a Band-Aid. As much as 20 percent of each microneedle can fail to dissolve and cling to its patch. Since these remnants still hold drugs, patients may get an incomplete dose.
Mounting the patches’ spikes to a flexible, water-soluble sticker ensures that they stay embedded in the skin, reports Katherine Moga of the University of North Carolina at Chapel Hill and colleagues July 29 in Advanced Materials.
Moga’s team filled microneedles with fluorescent dye, stuck them to the flexible backing and then placed the patches onto slices of mouse and human skin. Squirting water onto the patch dissolved the backing, leaving the spikes in place and letting them shed all their dye into the skin.
The completely dissolvable device could help doctors ensure they deliver full doses of medication to their patients, the authors suggest.