Methacrylated Gelatin-Based Conductive Self-Healing Hydrogels: A Dual-Scale Approach for Micro- and Macro-Sized Soft Materials

Abstract

Soft robotic microsystems, inspired by the flexibility of biological structures, have gained significant research interest due to their ability to navigate complex environments with high adaptability. Electroconductive hydrogels (ECHs) have emerged as promising materials for these systems, offering intrinsic softness, biocompatibility, and electrical conductivity. Here we present a electroconductive hydrogel with multifunctionality developed by a dual-component conductive strategy, incorporating polyaniline (PANI)-silver (Ag) nanoparticles into a methacrylated gelatin (GelMa) network. The hydrogel was fabricated using a dual-scale production approach, where UV crosslinking was employed for macroscale structuring and two-photon lithography enabled high-resolution microscale structuring. This hierarchical fabrication method allowed for the precise design of microarchitectures leading to new innovations in soft materials by optimizing their performance. Moreover, the hydrogel demonstrated self-healing properties, facilitating autonomous recovery of both mechanical and electrical functionalities after damage, which is crucial for long-term application in dynamic environments. Comprehensive characterization, including morphological, electrical, mechanical, and biological tests, confirmed its conductivity, cytocompatibility, and tunable mechanical properties. The results suggest that this biopolymer-based, electroconductive hydrogel with self-healing ability is a highly promising candidate for next-generation soft robotic systems, offering a durable, adaptable, and bio-integrated solution for further soft robotic applications in both macro and micro scales.