Photoactivable Surfactant Design for In Situ Stabilization of Hydrogel Bioelectronics.

Conductive polymer hydrogels offer unique advantages for soft, stretchable biointerfaces by combining tissue-like mechanics with high ionic conductivity. However, their reliable integration with hydrophobic substrates and encapsulants essential for electrical insulation and chemical protection remains a major challenge due to poor wetting and interfacial delamination in aqueous environments. Here, we report a facile strategy for the in situ stabilization of conductive polymer hydrogels on hydrophobic substrates using a photoactivable surfactant (PAS). PAS reduces interfacial surface energy and, upon UV activation, forms covalent bonds with stretchable substrates, thereby yielding strong adhesion and long-term stability under wet conditions. This molecular design also enables photopatterning of hydrogels without compromising performance. Notably, PAS not only stabilizes and patterns conductive hydrogels in situ but also enhances their mechanical and electrical properties. PAS-integrated hydrogel biointerfaces exhibit robust operation in aqueous environments and demonstrate reliable in vivo electromyographic (EMG) signal recording, underscoring the potential of this approach for next-generation implantable and wearable bioelectronics.