High-precision electrohydrodynamic printing of EGaIn-AgNPs biphasic conductive ink for conformal and lightweight bioelectrodes

Low-melting-point liquid metals (LMs), characterized by exceptional electrical conductivity, mechanical compliance, and eco-friendly, cost-effective processability, hold great promise as flexible conductors in human-machine interfaces, wearable bioelectronics, and emerging technologies. However, their intrinsic fluidity compromises device stability, while high surface tension and low viscosity present significant challenges for high-resolution patterning and scalable manufacturability. In this study, we develop a eutectic gallium indium-silver nanoparticles (EGaIn-AgNPs) biphasic conductive ink and employ electrohydrodynamic printing to achieve precise, high-resolution patterning of the EGaIn-AgNPs biphasic structure (~5 μm). This approach strategically embeds a solid phase within the LM matrix, effectively suppressing its inherent fluidity and substantially augmenting its mechanical stability and structural robustness. By leveraging the versatility and precision of electrohydrodynamic printing, we successfully fabricate lightweight, highly resolved conductive patterns that can conform seamlessly to complex and dynamic surfaces, such as human skin and plant leaves. This advancement addresses key challenges in LM-based flexible electronics, unlocking transformative opportunities in wearable electronics, implantable devices, next-generation consumer electronics, and smart agricultural systems.