State-of-the-art in functionalized 3D/4D-printed magnetic hydrogels for environmental and biomedical applications

The field of functionalized 3D/4D-printed magnetic hydrogels has arisen as a dynamic and speedily advancing research area, combining the versatility of hydrogels with the inimitable nature of magnetic nanoparticles. This review offers a comprehensive overview of recent developments in the composition, synthesis, and 3D/4D printing techniques of magnetic hydrogels, emphasizing their budding applications in biomedical, soft robotics, and environmental remediation. Key advancements include the integration of magnetic nanoparticles into hydrogel matrices, enabling controlled mechanical and magnetic responses, as well as the refinement of 3D/4D printing methods that enhance precision, scalability, and functionalization. Despite significant progress, challenges such as material scalability, reproducibility, and environmental concerns remain, necessitating further research. Additionally, the review highlights the potential for future applications and suggests promising research directions, including the growth of personalized biomedical devices, smart environmental sensors, and adaptive manufacturing systems. This review aims to provide an appreciated resource for researchers and engineers, guiding future innovations in the design and application of functionalized 3D/4D-printed magnetic hydrogels.