Superparamagnetic Iron Oxide Nanoparticles (SPION) are an important class of nanomaterials used for biomedical applications like drug delivery, MRI or hyperthermia. For these applications SPION are equipped with a polymeric or lipid shell to sterically stabilize the SPION and to avoid aggregation and precipitation. The performance of these nanoparticles (NPS) in biomedical applications relies strongly on their structural properties, i.e. size, shape, crystallinity and polydispersity of the core as well as stability, density and uniformity of the shell. These properties will influence the colloidal stability, protein adsorption and thus the interaction of the NPs with the cells of the body. We present the synthesis and a throughout in situ synchrotron SAXS and SANS structural study of novel sophorolipid coated SPION. In situ synchrotron SAXS was used to investigate the formation mechanism and intermediate species of the SPION core synthesis by thermal decomposition while the morphology and crystallinity of the SPION was investigated with TEM. In a second step, the hydrophobic shell of as-synthesized SPION was replaced by a new biobased ligand: sophorolipid (SL). The glycolipid was chemically grafted to the NP surface by using nitrodopamine, a catechol derived anchor group to make biocompatible core-shell SPION (SL-SPION). The structure of the SL-SPION was studied with small angle neutron scattering (SANS) and could be fitted with a core-shell model to reveal the thickness of the shell. The core-shell structure of the SL-SPION was shown to translate into exceptional colloidal stability at high ion and protein concentrations and at high temperatures as shown by SANS and DLS. Absent cytotoxicity verified the biocompatibility of this new hybrid material. SL-SPION combine the superparamagnetic properties of iron oxide with the interesting inherent targeting and anti-bacterial properties of sophorolipids resulting in a promising new material for biomedical applications.

Sophorolipid-coated superparamagnetic iron oxide nanoparticles: Synthesis and structure

255th National Meeting (2018)

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