Suchergebnisse

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 ...

In the field of tissue engineering and regenerative medicine, hydrogels are used as biomaterials to support cell attachment and promote tissue regeneration due to their unique biomimetic characteristics. The use of natural-origin materials significantly influenced the origin and progress of the field due to their ability to mimic the native tissuesâ extracellular matrix and biocompatibility. However, the majority of these natural materials failed to provide satisfactory cues to guide cell differentiation toward the formation of new tissues. In addition, the integration of technological advances, such as 3D printing, microfluidics and nanotechnology, in tissue engineering has obsoleted the first generation of natural-origin hydrogels. During the last decade, a new generation of hydrogels has emerged to meet the specific tissue necessities, to be used with state-of-the-art techniques and to capitalize the intrinsic characteristics of natural-based materials. In this review, we briefly examine important hydrogel crosslinking mechanisms. Then, the latest developments in engineering natural-based hydrogels are investigated and major applications in the field of tissue engineering and regenerative medicine are highlighted. Finally, the current limitations, future challenges and opportunities in this field are discussed to encourage realistic developments for the clinical translation of tissue engineering strategies. ; Authors acknowledge financial support from the European Union Framework Programme for Research and Innovation Horizon 2020 under European Research Council grant agreement No. 772817; FCT (Fundação para a Ciência e a Tecnologia) for individual fellowship CEECIND/01375/2017 (MGF); FCT for project PTDC/NAN-MAT/30595/2017; Xunta de Galicia for postdoctoral fellowship ED481B-2019-025 (AP); Norwegian Research Council (NFR) for project No. ...