Integrating electrical conductivity capability into 3D printed alginate-gelatin hydrogels as skin tissue constructs for temperature sensing

The development of electrically conductive hydrogels has emerged as a critical advancement in soft electronics, enabling multifunctional devices for biomedical applications. This work introduces biocompatible and conductive three-dimensional (3D) printed hydrogels based on alginate-gelatin matrices, modified with gold nanoparticles (AuNPs) and MXene nanosheets (Ti₃C₂Tₓ), as electronic-engineered skin hybrid platforms for temperature sensing. The hydrogels demonstrate tunable conductivity, reaching values of 0.44 S/m for AuNP-modified and 1.04 S/m for MXene-modified samples. Structural analysis confirmed the preservation of a porous architecture, while rheological studies highlighted their mechanical integrity. Both modifications imparted temperature sensitivity, with an approximately 20 % increase in current response between 30 °C and 40 °C and sensitivities in the range from -1.54-2.00 %ºC^-1. These hydrogels also exhibit excellent cytocompatibility, making them ideal candidates for engineered skin scaffolds. The combination of temperature sensing and biocompatibility advances the potential use of conductive hydrogels in real-time physiological monitoring and infection detection, marking a significant contribution to the field of bioelectronics.