Tufts researchers develop fab process for microneedle patch

Bioengineers at Tufts University School of Engineering recently published the details behind a new fabrication process they developed for producing a silk-based microneedle system capable of delivering precise amounts of drugs over time without the need for refrigeration.

While such microneedle systems have been around for some time, the production of such devices "has been limited by constraints ranging from harsh manufacturing requirements that destroy sensitive biochemicals, to the inability to precisely control drug release or deliver sufficient drug volume, to problems with infections due to the small skin punctures," according to a Dec. 21 Tufts University news release.

The new fabrication process developed by Tufts bioengineers reportedly resolves these limitations.

According to Tufts: "The process involves ambient pressure and temperature and aqueous processing. Aluminum microneedle molding masters were fabricated into needle arrays of about 500µm needle height and tip radii of less than 10µm. The elastomer polydimethylsiloxane was cast over the master to create a negative mold; a drug-loaded silk protein solution was then cast over the mold.

"When the silk was dry, the drug-impregnated silk microneedles were removed. Further processing through water vapor annealing and various temperature, mechanical and electronic exposures provided control over the diffusity of the silk microneedles and drug release kinetics.

The research paper "Fabrication of Silk Microneedles for Controlled-Release Drug Delivery" appeared in the Dec. 2 issue of Advanced Functional Materials online.