Enhanced electrochemical performance of neural electrodes based on PEDOT:PSS hydrogel

Abstract

Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has attracted much attention on applications of neural interfaces and other biomedical fields due to its excellent electrical performances and good biocompatibility. However, its stability still remains challenge. Here, a conductive polymer hydrogel (CPH) made from PEDOT:PSS is modified on platinum (Pt) substrate successfully through electrochemical gelation, employing copper (Cu) as the sacrificial layer. The as-prepared CPH electrode provides extensive large surface area with good adhesion after dried in the air. The uniform flower-like structure helps the electrode achieve a significantly low square impedance down to 10.09 Ω cm 2 (reduction of 54.89%) at 1 kHz, compared with that of bare Pt. It exhibits a high cathodic charge storage capacity (CSC c ) up to 82.36 mC cm À2 , about 27 and 16.18 times higher than that of bare Pt and PEDOT:PSS coating respectively. Besides, no obviously variation of CSC c occurs after 5 CV cycles in phosphate buffered saline (PBS), and superior charge injection capacity (CIC) was also observed. Such CPH material presents great potential for preparing functionalized flexible electrode, implying promising applications on neural implants and other flexible electronics.

Novel Trends in Hydrogel Development for Biomedical Applications: A Review

“…Composite hydrogels that include metal nanoparticles (NPs) and metal oxides are one of the most studied trends for the development of biomaterials, since these materials have beneficial properties, such as their ability to respond to physical stimuli (electrical, magnetic and light) and good antimicrobial activity [ 230 ]. Metallic nanoparticles mainly include noble metals such as silver (Ag) [ 231 ], gold (Au) [ 232 ] and platinum (Pt) [ 233 ], whereas metal oxide nanoparticles include titania (TiO 2 ) [ 234 ], iron oxide (Fe 3 O 4 , Fe 2 O 3 ) [ 235 ], zirconia (ZrO 2 ) [ 236 ], alumina (Al 2 O 3 ) [ 237 ] and zinc oxide (ZnO) [ 238 ]. The incorporation of noble metal NPs has indeed added advantageous functionality to hydrogels for biomedical applications.…”

New Era of Electroceuticals: Clinically Driven Smart Implantable Electronic Devices Moving towards Precision Therapy

“…In this study, a percutaneous connector was used as a direct electrical connection, allowing flexible neurostimulation and electrode monitoring without the need for any implanted devices [117]. Though the number of developments with different electrode configurations revealing reliable retinal prostheses, more recently, the advanced materials-inspired electrode systems are attracting for implantable devices, neural interfaces, and other biomedical fields due to their enhanced electrochemical performance, electrical activity, and biocompatibility [118]. For example, a hydrogel-electrode system was developed on the platinum substrate with the modified poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PE-DOT-PSS) via electrochemical gelation process, employing copper as a sacrificial layer [118].…”

“…This conductive polymer hydrogel electrode material provides an extensive large surface area with good adhesion. Such material presents a great potential for preparing flexible, functional electrodes imploying promising applications in neural implants [118]. Combining photo-capacitor-inspired energy storage devices with hydrogel-based electrodes would open up novel solutions to restore vision with high resolution while maintaining biocompatibility in patients [115,116].…”

“…Combining photo-capacitor-inspired energy storage devices with hydrogel-based electrodes would open up novel solutions to restore vision with high resolution while maintaining biocompatibility in patients [115,116]. Furthermore, integrating a photovoltaic array with hydrogel electrode-inspired stimulating sources or micro photodiode array adopted hydrogel electrode systems would be useful Though the number of developments with different electrode configurations revealing reliable retinal prostheses, more recently, the advanced materials-inspired electrode systems are attracting for implantable devices, neural interfaces, and other biomedical fields due to their enhanced electrochemical performance, electrical activity, and biocompatibility [118]. For example, a hydrogel-electrode system was developed on the platinum substrate with the modified poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) via electrochemical gelation process, employing copper as a sacrificial layer [118].…”

“…Furthermore, integrating a photovoltaic array with hydrogel electrode-inspired stimulating sources or micro photodiode array adopted hydrogel electrode systems would be useful Though the number of developments with different electrode configurations revealing reliable retinal prostheses, more recently, the advanced materials-inspired electrode systems are attracting for implantable devices, neural interfaces, and other biomedical fields due to their enhanced electrochemical performance, electrical activity, and biocompatibility [118]. For example, a hydrogel-electrode system was developed on the platinum substrate with the modified poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) via electrochemical gelation process, employing copper as a sacrificial layer [118]. The morphology helps the hydrogel-based electrode to achieve a significantly low impedance down to 10.09 Ω cm 2 at 1 kHz.…”