Hybrid alginate beads embedding lipid mesophase nanoparticles: structural preservation and pollutant uptake...

We hypothesized that embedding nanostructured lipid mesophase particles within alginate beads would preserve their internal structure and functional pollutant uptake capacity while improving handling. To test this, hybrid beads were prepared by incorporating monolinolein/ bio-sourced squalane dispersions into calcium-crosslinked alginate beads, with the internal mesophase structure tuned through lipid/oil composition. Small Angle X-ray Scattering (SAXS) revealed that increasing squalane content induced transitions between cubic, hexagonal, and isotropic L₂ phases, demonstrating the structural versatility of the lipid core. Rheological measurements guided the optimization of alginate concentration for stable bead formation. We also investigated the interactions between alginate, lipid mesophase dispersions, and calcium during encapsulation process. Cryo-SEM imaging of pure and hybrid alginate beads confirmed the homogeneous dispersion of mesophase nanoparticles within the polymer matrix and the preservation of the overall porous network of the composite material. Cryo-TEM imaging validated the internal organization of nanoparticles prior embedding and confirmed that the structural integrity of the lipid mesophase was maintained within the alginate beads. Pollutant uptake tests using bisphenol A showed that the hybrid beads retained the absorption efficiency of the free lipid dispersions. These results demonstrate that the nanostructured lipid mesophase particles can be embedded within alginate hydrogel beads while preserving both their internal nanostructure and their absorption properties, providing a simple strategy to translate lipid self-assembled systems into macroscopic and easily recoverable materials.