Magnetic nanocomposite hydrogels for tissue engineering: design concepts and remote actuation strategies to control cell fate

Most tissues of the human body are characterized by highly anisotropic physical properties and biological organization. Hydrogels have been proposed as scaffolding materials to construct artificial tissues due to their water-rich composition, biocompatibility and tunable properties. However, unmodified hydrogels are typically composed of randomly oriented polymer networks, resulting in homogeneous structures with isotropic properties different from those observed in biological systems. Magnetic materials have been proposed as potential agents to provide hydrogels with the anisotropy required for their use on tissue engineering. Moreover, the intrinsic properties of magnetic nanoparticles enable their use as magnetomechanic remote actuators to control the behavior of the cells encapsulated within the hydrogels under the application of external magnetic fields. In this review, we combine a detailed summary of the main strategies to prepare magnetic nanoparticles showing controlled properties with an analysis of the different approaches available to their incorporation into hydrogels. The application of magnetically-responsive nanocomposite hydrogels in the engineering of different tissues is also reviewed.

We acknowledge European Union’s Horizon 2020 Research and Innovation Programme—European Research Council Consolidator Grant MagTendon (Agreement No. 772817) and Project Achilles (Agreement No. 810850) and Fundação para a Ciência e Tecnologia (FCT) for Project SmarTendon-PTDC/NAN-MAT/30595/2017 and Project MagTT-PTDC/CTM-CTM/29930/2017, from NORTE-01-0145-FEDER-000021 supported by Norte Portugal Regional Operational Programme (NORTE 2020). We also thank Agencia Estatal de Investigación by Project MAT2016-80266-R and Xunta de Galicia (Grupo de Referencia Competitiva ED431C 2018/26 and ED431C 2018/09; Agrupación Estratégica en Materiales ED431E 2018/08). A.P. is grateful to Xunta de Galicia for his postdoctoral fellowship ED481B2019/025. ERDF funds are also acknowledged.