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

## TL;DR

This paper introduces a new bioink that is both thermoresponsive and electrically conductive, suitable for 3D printing electroactive tissues and bioelectronics.

## Contribution

The study systematically formulates and evaluates a bioink that combines thermoresponsiveness, conductivity, printability, and biocompatibility in one material.

## Key findings

- A bioink formulation with 2% agarose, 4% gelatin, 2% HPC, and 0.1% PEDOT:PSS achieved optimal performance in conductivity and biocompatibility.
- 3D-printed structures showed micro- to mesoscale pores suitable for cell infiltration and molecule transport.
- The bioink maintains structural stability and high print fidelity without postprinting modifications.

## Abstract

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.