Microfabricated Conductive PEDOT:PSS Hydrogels for Soft Electronics

Soft electronics integrate biology, materials science, and electronic engineering to create devices that could seamlessly interface with biological systems. Among soft electronic materials, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) hydrogels are distinguished by their combined ionic–electronic conductivity, tissue-like mechanics, and biocompatibility. Despite these advantages, PEDOT:PSS hydrogels still face challenges, including high water content, mechanical weakness, and limited adhesion to conventional electronic materials. These challenges are further intensified by the incompatibility of PEDOT:PSS with high-temperature processing and chemically demanding fabrication techniques. Consequently, research has increasingly focused on developing PEDOT:PSS hydrogels with advanced fabrication methods that enable scalable production, complex structure, and high resolution to meet the requirements of soft electronics. This review explores the integration of PEDOT:PSS hydrogels with soft electronics from hydrogel-to-device and device-to-hydrogel perspectives. It explores strategies to enhance the performance of PEDOT:PSS hydrogels and address fabrication challenges. Both top-down (e.g., scalable fabrication and high precision) and bottom-up (e.g., tunable conductivity and multifunctionality) approaches are examined, emphasizing advances that improve hydrogel integration with manufacturing technologies. By analyzing these design principles, this review contributes to hydrogel-based microfabrication and soft electronics, driving developments in bioelectronics, soft sensors, and soft robotics.