Ex situ and in situ Magnetic Phase Synthesised Magneto-Driven Alginate Beads

[EN] Biocompatible magnetic hydrogels provide a great source of synthetic materials, which facilitate remote stimuli, enabling safer biological and environmental applications. Prominently, the ex situ and in situ magnetic phase integration is used to fabricate magneto-driven hydrogels, exhibiting varied behaviours in aqueous media. Therefore, it is essential to understand their physicochemical properties to target the best material for each application. In this investigation, three different types of magnetic alginate beads were synthesised. First, by direct, ex situ, calcium chloride gelation of a mixture of Fe3O4 nanoparticles with an alginate solution. Second, by in situ synthesis of Fe3O4 nanoparticles inside of the alginate beads and third, by adding an extra protection alginate layer on the in situ synthesised Fe3O4 nanoparticles alginate beads. The three types of magnetic beads were chemically and magnetically characterised. It was found that they exhibited particular stability to different pH and ionic strength conditions in aqueous solution. These are essential properties to be controlled when used for magneto-driven applications such as targeted drug delivery and water purification. Therefore, this fundamental study will direct the path to the selection of the best magnetic bead synthesis protocol according to the defined magneto-driven application.Authors acknowledge the MaMi project, funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 766007. We acknowledge funding support from “Ministerio de Ciencia y Educación de España” under grant PID2020-120313 GB-I00 / AIE / 10.13039/501100011033, and Gobierno Vasco Dpto. Educación for the consolidation of the research groups (IT1271-19). Special thanks to Prof. J. M. D. Coey for his help during the work performed in his laboratories and to (SGIker) of the University of the Basque Country (UPV/EHU) and Dr. Francisco Bonilla from CIC energiGUNE (Spain) for the technical support