Printable Conductive Hydrogels for Electrochemical Biosensing and Soft Bioelectronic Interfaces

ABSTRACT The development of flexible, conductive biomaterials is key to advancing next‐generation biosensors and wearable health monitoring systems. However, combining printability, mechanical tunability, biocompatibility, and electronic performance within a single hydrogel remains a significant challenge. Here, we present a facile method to fabricate biofunctional conducting poly(ethylene glycol)–poly(pyrrole) (PEG–PPy) hydrogels via 3D‐printing. The soft and flexible PEG–PPy hydrogels feature tunable mechanical properties and can be easily loaded with bioreceptors, enabling integration into sensing platforms. The composite consists of a poly(ethylene glycol) diacrylate matrix and a conductive polypyrrole filler. By optimizing photopolymerization conditions, we enable extrusion printing of complex, multi‐layered structures with excellent shape fidelity (printability ≈ 1). The resulting hydrogels exhibit tunable stiffness (15–120 kPa), high cytocompatibility (>90%), and robust mechanical integrity. Integration of the hydrogel as a gate electrode in an organic electrochemical transistor yielded transconductance values comparable to conventional Ag/AgCl gates, confirming its electrochemical performance. Furthermore, embedding glucose oxidase into the hydrogel enabled enzymatic glucose sensing over a physiologically relevant range (1–100 m m ). This cost‐effective, multifunctional, and versatile PEG–PPy hydrogel platform offers a scalable route toward soft, flexible, printable electronic interfaces.