A covalently bonded exchange coupled nanomagnet-based hydrogel composite for microrobotic applications

The last decade has witnessed rapid progress in the development of soft microrobots for biomedical applications, largely powered by the incorporation of new materials in their design to address various challenges. In this study, we introduce a unique magnetic nanoparticle-hydrogel composite designed for microrobot applications. This composite comprises iron platinum-zinc ferrite nanoparticles whose magnetic properties are enhanced by magnetic exchange-coupling behavior. The introduction of zinc ferrite further allows for grafting alkyne-bearing ligands on the nanoparticles, enabling them to be covalently immobilized within the hydrogel framework via azide-alkyne cycloaddition, thereby improving the composite’s stability. Using a template-assisted 3D fabrication technique, we demonstrated the feasibility of using this composite for soft microrobots. Hence, one could assume this straightforward procedure to be easily adapted to other material systems, facilitating the creation of more customized soft microrobots.