Silk may be basis for smoothest microneedle system yet

Silk isn't just for fabric anymore. Tufts University researchers have determined that its unique properties contribute to a versatile, more precise and safer microneedle drug delivery system.

An article posted online with the U.K.-based The Royal Society of Chemistry's Chemistry World publication explains the finding in detail.

Tufts researchers David Kaplan and Fiorenzo Omenetto--along with others at the university--believe that microneedle tech using silk improves upon existing microneedle systems made from sugars, synthetic polymers and other materials. Silk-based systems, they determined, could be more precise, safer, help keep patients from developing skin infections and also control drug release with greater precision because of how silk entraps the drug within it, the article notes. It also turns out that silk microneedles are biodegradable, and microneedle patches have been long known to skirt the pain that hypodermic needles can cause.

The Tufts team built their silk microneedles by first using a form of silicone to create an elastomer-based negative mold of a microneedle array. Next, they loaded the drug into a silk fibroin solution obtained from silk worm cocoons (which is then cast over the template and left to dry). The scientists then determined that they could adjust how the silk microneedles degraded, and diffused the drug, by adjusting the silk's hydration state. The resulting system operates kind of like a band-aid, with no refrigeration required.

Worth noting--a silk microneedle has enough room for antibiotics, too. They tested the microneedles on hydrogel skin models in the lab, loaded with an antibiotic, and a cell culture revealed a significant reduction in bacterial density, according to the article.

Researchers are pursuing the use of various kinds of microneedle patches to treat osteoporosis and cancer, or to deliver flu and polio vaccines.

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