By Sophie Bushwick
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Nobody likes getting shots. But what if you could make the needles so tiny that they broke the skin painlessly? Engineers from Tufts University have created such micro-needles—made from the major protein in silk, fibroin. The work is in the journal Advanced Functional Materials.[Konstantinos Tsioris et al., "Fabrication of Silk Micro-Needles for Controlled-Release Drug Delivery"]
The researchers created molds for arrays of needles just 500 microns tall and 10 microns wide. That’s a tenth the width of the average human hair. They then poured a solution of fibroin mixed with a drug into the molds. The resulting micro-needles are dried and undergo further processing.
In tests, a patch containing numerous micro-needles successfully released the drug, which maintained its biological activity. The tiny needles are too short to reach the nerves under the skin, so they can deliver drugs without the pain of a traditional shot. Even better, they can gradually release medication over time. While skin patches and slow-release pills are currently used for this purpose, they only work with certain kinds of medication. The new micro-needle system could make the gradual delivery of many drugs smooth as silk.