Conductive polymer hydrogels crosslinked by electrostatic interaction with PEDOT:PSS dopant for bioelectronics application

Conductive hydrogels based on pure-phase conductive polymers have great promise in bioelectronic device and energy device application. However, commonly-used crosslinking agents for conductive polymers, such as phytic acid (PA), have low conductivities and therefore limit the improvement in the conductivity of conductive polymer hydrogels (CPHs). Herein, we explore a general approach using PEDOT:PSS as conductive dopant to crosslink various conductive polymers, including polyaniline (PAni), polypyrrole (PPy), and Poly-aminoindole (PIn-X-NH2, X = 4, 5, 6, 7). The synthesis mechanism of the conductive hydrogels is based on the electrostatic interaction between negatively charged SO3- groups in PEDOT:PSS and positively charged PAni, PPy, PInX-NH2 polymer chains. In comparison with the CPHs crosslinked with PA, the CPHs crosslinked with PEDOT:PSS have much higher conductivities and greatly improved biocompatibilities, which are highly demanded for bioelectronics application. The CPHs crosslinked with PEDOT:PSS are demonstrated to serve as electroactive interfacial materials for in situ electrochemical sensing of bioactive molecules, such as dopamine and hydrogen peroxide, released from living cells. Our novel strategy for the fabrication of CPHs with commercially available PEDOT:PSS as conductive crosslinking dopant would provide great opportunities in the construction of highly conductive hydrogels for versatile applications in bioelectronics and energy devices.