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

Area of Science:

• Biomaterials Science
• Neuroscience
• Drug Delivery Systems

Background:

• Spinal cord injury triggers secondary damage via inflammation and cytotoxicity.
• Effective local delivery of anti-inflammatory drugs is crucial for mitigating this secondary injury.
• Minimizing dural opening during drug delivery is a significant challenge.

Purpose of the Study:

• To develop a polypyrrole (PPy)-coated microneedle array for controlled transdural drug delivery.
• To investigate the electronically controlled release of dexamethasone (Dexa) via PPy microneedles.
• To evaluate the efficacy of this system in reducing neuroinflammation.

Main Methods:

• Fabrication of PPy-coated microneedle arrays using 3D printing technology.
• Development of a novel in vitro transdural model for drug release studies.
• In vitro testing using activated microglia to model neuroinflammation.
• In vivo evaluation of drug release and biological activity.

Main Results:

• Demonstrated electronically controlled release of dexamethasone (Dexa) from PPy microneedles in vitro and in vivo.
• Successfully reduced nitric oxide and pro-inflammatory cytokines (Il-6, MCP-1) in an in vitro neuroinflammation model.
• Confirmed the biological activity of electronically released Dexa in reducing inflammation.

Conclusions:

• Polypyrrole-coated microneedles offer a feasible method for transdural drug delivery to the central nervous system.
• This technology facilitates localized and electronically controlled release of anti-inflammatory agents.
• The PPy microneedle system shows promise for treating secondary injury following spinal cord injury.