Polypyrrole‐coated electrodes show thickness‐dependent stability in different conditions during 42‐day follow‐up in vitro

Abstract

Electroconductive polypyrrole/dodecylbenzenesulphonate (PPy/DBS) has been proposed as novel electrode coating for biomedical applications. However, as yet, little is known about its long-term stability in moist conditions. This study compares the stability of PPy/DBS-coated platinum electrodes that are either dry-stored, incubated, or both incubated and electrically stimulated. The electrical and material properties of three different coating thicknesses were monitored for 42 days. Initially, the PPy/DBS-coating decreased the low frequency impedance of the platinum electrodes by 52% to 79%. The dry-stored electrodes remained stable during the follow-up, whereas the properties of all the incubated electrodes were altered in three stages with thickness-dependent duration: stabilization, stable, and degradation. The coated electrodes would be applicable for short-term, low-frequency in vitro measurements of up to 14 days without electrical stimulation, and up to 7 days with stimulation. The coating thickness is bound to other coating properties, and should therefore be selected according to the specific target application. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2202-2213, 2018.

Self‐Powered Controllable Transdermal Drug Delivery System

“…The impedance of PLA‐Au‐PPy MN array with the polymerization charge of 300, 400, and 500 mC cm –2 were 956, 1108, and 3666 Ω in 1 Hz matching the frequency of the human motion, indicating the impedance of PPy film increase with the film thickness. [ 37 ] Cyclic voltammetry (CV) was applied to explore the redox behavior of PLA‐Au‐PPy MNs. As shown in Figure 3g.…”

“…[ 39 ] While under pulsed electrical stimulation, PPy film continuously transforms between oxidation and reduction states, which maintains the conductivity of PPy film and promotes the diffusion of drugs, resulting in higher drug release efficiency. [ 37 ] Further, we explored the biocompatibility of the microneedle materials and the anti‐inflammatory activity of Dex released from the MNP with RAW 267.4 cells in vitro. The results showed that the viability of the cells was above 85% (Figure S8c, Supporting Information), and the concentration of the pro‐inflammatory mediators IL‐6 and TNF‐α induced by LPS was obviously decreased after treatment with Dex from the sc‐TDDS (Figure 4h,i).…”

Development and Characterization of Electrodes Coated with Plasma-Synthesized Polypyrrole Doped with Iodine, Implanted in the Rat Brain Subthalamic Nucleus

“…One such biocompatible material is polypyrrole (PPy), composed of heterocyclic molecules with five members, including four carbons and one nitrogen, featuring conjugated double bonds [ 5 ]. Due to their broadly tailorable properties, PPy coatings have a broad range of different biomedical application areas, such as tissue engineering scaffolds, implant coatings, drug delivery devices, and recording and stimulation applications [ 6 ]. Electrically conductive polymers, such as PPy, have undergone extensive research for their applications as active electrode materials and supporting additives across various domains, including electronics, batteries, electrodes, and biomaterials [ 7 ].…”