Biochemically Controlled Release of Dexamethasone Covalently Bound to PEDOT

PEDOT (Poly(3,4-ethylenedioxythiophene)) is one of the most promising electrode materials for biomedical applications like neural recording and stimulation, thanks to its enhanced biocompatibility and electronic properties. Drug delivery by PEDOT is typically achieved by incorporating drugs as dopants during the electrodeposition procedure and a subsequent release can be promoted by applying a cathodic trigger that reduces PEDOT while enabling the drug to diffuse. This approach has several disadvantages including, for instance, the release of contaminants mainly due to PEDOT decomposition during electrochemical release. Herein we describe a new strategy based on the formation of a chemical linkage between the drug and the conductive polymer. In particular, dexamethasone was successfully integrated into a new electropolymerized PEDOT–Dex composite, leading to a self-adjusting drug release system based on a biochemically hydrolysable bond between dexamethasone and PEDOT.