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Microneedles For Painless Delivery Of Vaccines And Nanomedicines

ACS Meeting News: Within minutes, researchers fabricate tiny biodegradable hypodermics with encapsulated enzymes and nanoparticles

by Lauren K. Wolf
August 18, 2014 | A version of this story appeared in Volume 92, Issue 33

Credit: DeSimone Lab/UNC
A microneedle patch loaded with fluorescent dye sits atop a person’s finger.
Photo of a microneedle patch loaded with a fluorescent dye sitting atop a person’s finger.
Credit: DeSimone Lab/UNC
A microneedle patch loaded with fluorescent dye sits atop a person’s finger.

For safer, cheaper, and painless delivery of vaccines and protein-based drugs, scientists want to create arrays of needles short enough to avoid nerve cells but long enough to pierce a person’s skin. Research teams have developed these so-called microneedles, but fabricating the tiny hypodermics typically requires numerous steps and takes hours to days. Graduate student Katherine A. Moga described a method for mass-producing microneedle arrays within minutes and loading them with protein or nanoparticle therapeutics. Last year, Moga and other members of Joseph M. DeSimone’s research team at the University of North Carolina, Chapel Hill, adapted a process dubbed PRINT (Particle Replication in Non-wetting Templates) to manufacture microneedles made of the biodegradable polymer polyvinylpyrrolidone (Adv. Mater. 2013, DOI: 10.1002/adma.201300526). During the process, the team adds a mixture of polyvinylpyrrolidone and either enzymes or nanoparticles to a mold dotted with pyramid-shaped holes. When gently pressed into excised human skin or live mouse skin, the resulting microneedle patch punctures the surface and releases its cargo as it dissolves, Moga said. The team demonstrated that when encapsulated in the needles, the model enzyme butyrylcholinesterase remained almost 100% active. Similarly, polymer nanoparticles stayed intact, boding well for the tiny hypodermics’ future use to deliver vaccines and nanomedicines.

This week’s selections are from the ACS national meeting, which took place on Aug. 10–14 in San Francisco.


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