Magnetically responsive hydrogel systems: Fundamental features, emerging applications, and future horizons

Smart hydrogels have garnered significant attention due to their responsiveness to external stimuli. Magnetic-responsive hydrogels, in particular, are engineered by integrating magnetic nanomaterials into the hydrogel matrix. Their distinctive properties, including rapid magnetic responsiveness, precise spatial control, and the ability to exert non-invasive, remote forces, have expanded their potential in biomedical applications. Magnetic hydrogels exhibit various responses such as propulsion, deformation, and thermogenesis under an external magnetic field, offering deep tissue penetration for therapeutic purposes. This review aims to provide a comprehensive summary of recent advancements in the biomedical applications of magnetic hydrogels. It primarily explores the unique characteristics and fabrication techniques of these materials, as well as their various classifications and applications within the biomedical field. The challenges and future directions for preparing magnetic hydrogels are also discussed. • Comprehensive review of magnetic-responsive hydrogels for biomedical applications. • Focus on polymer-, protein-, and DNA-based MHs in controlled drug and gene delivery. • MHs offer rapid responsiveness, precise control, and non-invasive therapeutic potential. • Key insights into the fabrication techniques, classification, and challenges of MHs. • Emphasizes future directions for developing safer and more effective magnetic hydrogels.