A Thermoresponsive, Electrically Conductive Bioink Optimized for Electroactive Tissue Engineering and Bioelectronics

Achieving thermoresponsive behavior, electrical conductivity, printability, and biocompatibility within a single bioink formulation remains a significant challenge, yet this combination is essential for creating stable, electroactive 3D constructs that function under physiologically relevant conditions. To address this unmet need, this study aimed to develop a thermoresponsive and electrically conductive bioink through the systematic formulation and evaluation of 12 hydrogels composed of agarose, gelatin, HPC, and PEDOT:PSS. Among these, a formulation comprising 2% w/w agarose, 4% w/w gelatin, 2% w/w HPC, and 0.1% PEDOT:PSS exhibited the most balanced performance, demonstrating favorable shear-thinning rheology, high print fidelity, structural stability, and high electrical conductivity (0.5757 S/m). Comprehensive biological assays confirmed no significant changes in A549 cell viability across different embedding conditions, while SEM imaging of 3D-printed structures revealed micro- to mesoscale pores suitable for cell infiltration and small molecule transport. Critically, optimizing the PEDOT:PSS content enabled effective conductivity without compromising mechanical properties or biocompatibility. The systematic design approach demonstrated herein provides a reproducible framework for creating multifunctional conductive bioinks that successfully balance thermoresponsive behavior, printability, electrical conductivity, and biocompatibility in a single material. By integration of all essential functional properties into a single formulation, these findings advance the development of application-ready bioinks. The resulting printed structures can be used immediately, without any postprinting modification or functionalization, thereby supporting rapid translation into tissue engineering, biosensing, and bioelectronic applications.