Recent progress on smart hydrogels for biomedicine and bioelectronics

The increasing development of biomedicine and bioelectronics has highlighted the requirement for smart materials that can respond to changes in physical and chemical properties under external environments, such as magnetic fields, electric fields, and temperature. Accordingly, hydrogels have been widely evaluated as promising candidates for smart materials owing to their intriguing structures comprising a cross-linked network of polymer chains with interstitial spaces filled with solvent water. This feature endows hydrogels with soft and wet characteristics, which not only induce high tissue affinity but also allow the introduction of environmentally responsive nanoparticles to release specific smart properties. Herein, we reviewed novel smart hydrogels that can be applied in biomedicine and bioelectronics, and highlighted and discussed existing challenges in current technologies and research.