Design of biocompatible magnetic pectin aerogel monoliths and microspheres

Novel material formulations for biomedical uses containing magnetic nanoparticles are currently being explored. The synergistic combination of a polymeric matrix and a filler with magnetic properties in hybrid nanoporous materials (aerogels) will confer versatility to the product. In this work, the use of pectin aerogels as a biodegradable matrix containing maghemite nanoparticles (gamma-Fe2O3 NPs) is studied. The gamma-Fe2O3 NPs-loaded pectin aerogels are developed in two different morphologies (cylindrical monoliths and microspheres) prepared by a combination of sol-gel and supercritical drying methods. In the case of the aerogel microspheres, the sol-gel method was substituted by the emulsion-gelation procedure. The obtained aerogel-based materials were evaluated regarding their physical appearance and stability and their textural and magnetic properties. The particle size distribution and morphology of the aerogel microspheres were additionally analyzed by laser dispersion spectrometry, static image analysis and scanning electron microscopy. Process parameters influenced the distribution of the gamma-Fe2O3 NPs within the material. Whereas the gamma-Fe2O3 NPs were homogeneously distributed throughout the aerogel monoliths, gamma-Fe2O3 NPs were mostly deposited on the outer surface of the aerogel microspheres. The magnetic properties of maghemite were preserved in the end material after overall processing.