Conductive hollow hydrogel fibers toward high-sensitivity bio-textiles

Conductive hydrogels are becoming valuable in creating soft, flexible interfaces for biological tissue sensing due to their bio-compatibility and tissue-like mechanical properties. However, when tailored to epidermal sensors, they face low breathability and sensitivity issues, impacting long-term comfort and functionality. Addressing these issues, here we report sensing textiles from hollow conductive hydrogel fibers using co-axial microfluidic printing, allowing precise control of hollow channel diameters. The mesh-like textile demonstrates a sensitivity of 4.69 kPa⁻¹, significantly outperforming the solid-structured counterparts (0.77 kPa⁻¹). Moreover, the bio-textile demonstrates bio-compatibility, exhibiting no significant cytotoxic effects on human dermal fibroblasts after 3 days. To enhance durability and reusability, we integrate conductive fibers with metal wires for energy harvesting, achieving an open-circuit voltage output of ∼0.74 V. Notably, the voltage remains at ∼0.53 V even after dehydration. The high sensitivity, softness, and flexibility make our bio-textile a promising candidate for multifunctional sensing and energy harvesting in bio-interface devices.