Highly Conductive PPy–PEDOT:PSS Hybrid Hydrogel with Superior Biocompatibility for Bioelectronics Application

Abstract

Conductive polymer hydrogels (CPHs) hold significant promise in broad applications, such as bioelectronics and energy devices. Hitherto, the development of a facile and scalable synthesis method for CPHs with high electrical conductivity and biocompatibility has still been a challenge. Herein, we demonstrate highly conductive PPy–PEDOT:PSS hybrid hydrogels which are prepared by a simple solution-mixing method. This fabrication method involves the mixing of a pyrrole monomer with a PEDOT:PSS dispersion, followed by in situ chemical oxidative polymerization to form polypyrrole (PPy). The electrostatic interaction between negatively charged PSS and positively charged conjugated PPy facilitates the formation of PPy–PEDOT:PSS hybrid hydrogels. The conductivity of the PPy–PEDOT:PSS hybrid hydrogels is 867 S m–1. The PPy–PEDOT:PSS hybrid hydrogels show excellent biocompatibility. Moreover, the PPy–PEDOT:PSS hybrid hydrogels have a hierarchical porous structure which facilitates the 3D cell culture within the hydrogels. The PPy–PEDOT:PSS hybrid hydrogels exhibit excellent in situ biomolecular detection and real-time cell proliferation monitoring performance, indicating their potential as highly sensitive electrochemical biosensors for bioelectronics applications. Our strategy for the fabrication of CPHs with the electrostatic interaction between the negatively charged conductive polymer and positively charged conductive polymer would provide new opportunities for the design of highly conductive conjugated hydrogels for bioelectronics applications and energy devices.

Recent Progress on Self‐Healable Conducting Polymers

“…Hydrogels based on conducting polymers are of high interest for applications in bioelectronics, due to their good mechanical matching with human tissues, tunable electrical conductivity, high water content and biocompatibility. [ 124–127 ] Self‐healing ability can provide these materials enhanced durability and reliability, prolonging their lifetime. [ 128–130 ]…”

“…Hydrogels based on conducting polymers are of high interest for applications in bioelectronics, due to their good mechanical matching with human tissues, tunable electrical conductivity, high water content and biocompatibility. [124][125][126][127] Self-healing ability can provide these materials enhanced durability and reliability, prolonging their lifetime. [128][129][130] PEDOT-based hydrogels can be obtained by gelation of aqueous suspensions of the conducting polymer with nonvolatile compounds, such as agarose, lignin, alginates, guar gums or cellulose.…”

Poly(3,4‐ethylenedioxythiophene):Poly(styrene sulfonate) in antibacterial, tissue engineering and biosensors applications: Progress, challenges and perspectives

“…This shows a outlook in biomedical field for pressure regulations and sound detection. Most recently, Ren et al 137 have published PPy and PEDOT:PSS hybrid conductive hydrogel with significantly improved biocompatibility for bioelectronics. A simple solution mixing technique was adopted to prepare PPy‐PEDOT:PSS based hydrogel with porous structures.…”

“…Also, scanning confocal microscopy was used to detect the position of PC12 cells and results indicated the attachment of PC12 cells on the surface and also migration into the pores, facilitating the cell culture. The promising biocompatibility of conducting PPy‐PEDOT:PSS hydrogels allows their potential in the electrochemical biosensors 137 …”

The Bioanalytical and Biomedical Applications of Polymer Modified Substrates

“…Polymer hydrogels such as PDMS hydrogel and PEG hydrogel have been extensively applied for the construction of stretchable electronic devices because PDMS offers a number of attractive properties, including biocompatibility, ease of process, optical transparency and a moderate elastic modulus [149][150][151][152][153]. Zhang et al fabricated high-resolution metal microelectrodes with a channel length as short as 5 µm on PDMS by using ultrathin Parylene film (2 µm thick) transfer patterning (as shown in Figure 6) [149].…”