Improving the printability of Eutectic Gallium-Indium for fabrication of hydrogel-based biosensor

Soft, stretchable bioelectronics allows for conformal contact with anatomically distinct organs, allowing for precise real-time monitoring. Among the numerous biomaterials explored, hydrogels are well-favored because of its biocompatibility and tissue-like properties. Through the addition of conductive fillers or metallic salts, electrically conductive hydrogel can be fabricated to serve as biosensors. However, difficulties in achieving a good balance between electrical conductivity and tissue-like mechanical properties has limited the application of bioelectronics. Here, Eutectic Gallium-Indium (EGaIn) was explored as an alternative electrode material owing to its high conductivity and stretchability. This work presents the strategy explored in mitigating the low viscosity of EGaIn and the technique used to improve printability on polyacrylamide (PAAm) hydrogel.