3D-Printed Polypyrrole Microneedle Arrays for Electronically Controlled Transdural Drug Release

After the spinal cord injury, inflammation and cytotoxicity cause further damage to neural cells. The progression of this secondary injury might be reduced by the administration of anti-inflammatory drugs. To allow the local delivery of such drugswhile minimizing dural opening, we have created a polypyrrole(PPy)-coated microneedle array using a microscale three-dimen-sional (3D) printing technology that facilitates electronicallycontrolled encapsulation and the transdural release of drugs. PPymicroneedles demonstrated an electronically controlled release ofsteroid dexamethasone (Dexa) in a novel in vitro transdural modeland in vivo. The biological activity of the device was then tested by the electronic release of Dexa into an in vitro model ofneuroinflammation, using activated microglia. Following electrically activated Dexa release, inflammation was reduced, asdemonstrated by a decrease in nitric oxide and proinflammatory cytokines Il-6 and MCP-1. These results demonstrate the feasibilityof PPy-coated microneedles for the transdural delivery of anti-inflammatory drugs to the central nervous system

Automated summary

After spinal cord injury, inflammation and cytotoxicity cause further damage to neural cells. Research has found that the progression of this secondary injury can be reduced by administering anti-inflammatory drugs through a microneedle array for local delivery.