Hydrogels for Soft Robotics and Bio-Integrated Devices: Review on Self-Healing to Intelligent Actuation

Abstract Self-healing and shape memory hydrogels have emerged as a transformative class of materials poised to reform next-generation bioelectronics, soft robotics, and actuation systems. By combining biocompatibility, mechanical tunability, and autonomous repair properties, these materials offer unique advantages for designing resilient and multifunctional devices that mimic the adaptability and responsiveness of biological tissues. This review provides a comprehensive analysis of the recent progress in the molecular design, network architectures, fabrication strategies, and functional integration of self-healing hydrogels into smart devices. Emphasis is placed on understanding the dynamic bonding mechanisms involving reversible covalent and supra-molecular interactions that impart self-repair capabilities while balancing mechanical robustness, conductivity, and biocompatibility. Special attention is given to highlighting how self-healing and shape memory functionalities enhance device durability, responsiveness, and long-term performance. We further explore the role of stimuli-responsive mechanisms, such as pH, temperature, and electrical signals, in enabling adaptive actuation and signal transduction. Additionally, the key challenges such as healing speed, operational stability in physiological environments, and seamless multifunctionality have been discussed and outline future directions toward programmable, autonomous, and multifunctional hydrogel systems.