Electrochemically Controlled Drug Release from a Conducting Polymer Hydrogel (PDMAAp/PEDOT) for Local Therapy and Bioelectronics

Abstract

In this study, the release of fluorescein from a photo‐crosslinked conducting polymer hydrogel made from a hydrogel precursor poly(dimethylacrylamide‐co‐4‐methacryloyloxy benzophenone (5%)‐co‐4‐styrenesulfonate (2.5%)) (PDMAAp) and the conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) is investigated. Fluorescein, here used as a model for a drug, is actively released through application of an electrical trigger signal. The detected quantity is more than six times higher in comparison to that released from a conventional PEDOT/polysterene sulfonate (PSS) system. Release profiles, drug dose, and timing can be tailored by the application of different trigger signals and pretreatments. To demonstrate that the novel drug release system can be used for a drug relevant for local delivery to a neural interface, experiments are furthermore performed with the anti‐inflammatory drug dexamethasone (Dex). The conducting polymer hydrogel facilitates the active release of Dex, in comparison to the previously used PEDOT/Dex. It is suggested that PEDOT/PDMAAp is an interesting alternative for conducting polymer based drug release systems, with the potential to offer more volume for storage, yet retaining the excellent electrochemical properties known for PEDOT electrodes.

Nanoparticle Doped PEDOT for Enhanced Electrode Coatings and Drug Delivery

“…Since the stimulation ended after the total release had plateaued, the total release was considered similar to the total releasable drug load. The increase in dye loading, specifically fluorescein, was comparable to PEDOT hydrogels designed specifically for drug delivery; however, the passive diffusion release from these hydrogels is substantially higher than the PEDOT/SNP composite in this work . This result indicates that SNP doping not only improves drug loading and release capacity, but also broadens the drug choice as a majority of the previous conducting polymer drug release work focused on negatively charged drugs.…”

“…Examples including nanotubes and nanopores, graphene oxide, graphene/silica composites, and functionalized carbon nanotubes (CNT) have been successful in increasing the quantity of the drug payload. Conducting polymer hydrogels are capable of storing greater quantities of drug by increasing their volume . The ion pump approach can further circumvent this issue by incorporating a fluid channel and an external reservoir (which can be refilled), but this requires extensive microfabrication and is not immediately compatible with many current electrically interfacing devices.…”

Soft and Ion‐Conducting Materials in Bioelectronics: From Conducting Polymers to Hydrogels

“…In this fashion, charged small molecule drugs are delivered with precise spatiotemporal control . For example the anti‐inflammatory drug, dexamethasone, can be delivered using PDMAAp/PEDOT . Other polymer backbones include electroactive hybrid hydrogel composed of PEG diacrylate–polyacrylamide, PPy, and SWCNTs and reduced graphene oxide (rGO) nanosheets with PVA hybrid hydrogels.…”

“…[21,22,84] For example the anti-inflammatory drug, dexamethasone, can be delivered using PDMAAp/PEDOT. [85] Other polymer backbones include electroactive hybrid hydrogel composed of PEG diacrylate-polyacrylamide, PPy, and SWCNTs [86] and reduced graphene oxide (rGO) nanosheets with PVA hybrid hydrogels. In the PVA hybrid hydrogel, when the device is on, rGO works as a percolating pathway for transferring electrons and enhancing drug release.…”

Wafer‐Scale Fabrication of Conducting Polymer Hydrogels for Microelectrodes and Flexible Bioelectronics

“…CPHs furthermore enable the immobilization of biomolecules and thus have the potential to improve the device tissue integration by supporting neural cell adhesion and proliferation . In addition, CPHs have been proposed as advanced drug‐release systems which, as a result of their 3D hydrogel matrix and the swellability of the layers, facilitate the controlled release of higher drug quantities when compared to conventional CPs . A quality of great importance for making such coatings truly useful for multimodal applications is the possibility to selectively pattern the material on the device at a precision of a few micrometers.…”