Soft, stretchable conductive hydrogels for high-performance electronic implants
Md. Saifur Rahman, Ahnsei Shon, Rose Joseph, A.F. Pavlov, Alex Stefanov, Myeong Namkoong, Heng Guo, Dangnghi Bui, Reid Master, Archita Sharma, Jennifer Lee, Melissa Rivas, Ananya Elati, Yava Jones‐Hall, Feng Zhao, Hangue Park, Michelle A. Hook, Limei Tian
Abstract
Conductive hydrogels are emerging as promising materials for electronic implants owing to their favorable mechanical and electrical properties. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hydrogels are particularly attractive, but their preparation often requires toxic additives. Here, we introduced a nutritive sweetener, d-sorbitol, as a nontoxic additive to create soft and stretchable PEDOT:PSS conductive hydrogels. These hydrogels exhibit mechanical properties comparable with biological tissues, reducing adverse immune responses. The hydrogels can be patterned on elastic substrates using a simple, low-cost micromolding technique to fabricate soft and stretchable implantable devices for electrical stimulation and recording. The hydrogel electrodes show much lower electrochemical impedance and higher charge storage and injection capacity compared to platinum electrodes. In addition, the properties of hydrogels and devices remain stable after long-term storage and exposure to extreme conditions. We demonstrate the use of soft hydrogel-based electronic devices for effective electrical stimulation and high-quality electrical recordings in live animal models.