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

Abstract

The secondary injury causes further damage to neural cells, due to mechanisms of inflammation and cytotoxicity. Progression of secondary injury damage may be reduced by the administration of anti-inflammatory drugs. In order to allow local delivery of such drugs, while minimizing dural opening, we have created a Polypyrrole (PPy) microneedle array using micro-scale 3D printing technology that facilitates electronically controlled encapsulation and transdural release of drugs. The PPy microneedles demonstrated electronically controlled transdural release of steroid dexamethasone (Dexa) in a novel in vitro transdural model. Drug release capabilities of the device were then tested by electronic release of Dexa into an in-vitro model of activated BV2 microglia. After 72 hours of incubation, inflammation was reduced, as demonstrated by measured release of nitric oxide and Il-1b, a pro-inflammatory cytokine. These results demonstrate the feasibility of PPy microneedles for transdural delivery of anti-inflammatory drugs for spinal cord injury.