Synthesis and characterization of functional silica hybrid magnetic nanoparticles

Superparamagnetic iron oxide nanoparticles (SPIONs) show magnetic behavior only under a magnetic field. SPIONs are promising for many applications e.g. MRI contrast agents, magnetic hyperthermia treatment or drug delivery systems.

Naked SPIONs are not stable in water at physiological pH which consequently alters their magnetic properties and modifies the biocompatibility. To overcome this problem, SPIONs can be coated with a variety of materials such as surfactants, synthetic polymers or proteins to combine the magnetic properties with surface properties of the covering materials. A silica coating for example prevents aggregation, improves stability and can be functionalized by organosilanes offering different available chemical groups (e.g. amine group).

While many studies have focused on a two-step approach for silica coating the SPIONs and surface functionalization with 3-aminopropyltriethoxysilane, we have developed a single-step process by co-condensation of the silica precursor (tetraethyl orthosilicate, TEOS) and 3-aminopropyltriethoxysilane (APTES). The goal of this project is to understand the coating process behavior on the morphology of the obtained particles, as well as the magnetic responses and surface properties.


Principal investigator

Involved people

External partners

Prof. Ann Hirt

Institute for Geophysics, ETH Zurich

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