Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 67: Gerhard Ertl Young Investigator Award (talks of the selected canditates)

O 67.4: Talk

Thursday, March 25, 2010, 12:00–12:30, H37

Assembly of core-shell superparamagnetic iron oxide nanoparticles and their application to smart materials — •Erik Reimhult — ETH Zürich, Zürich, Switzerland

Application of superparamagnetic iron oxide nanoparticles (SPIONs) as biomedical imaging contrast agents and as smart materials require them to retain high stability even in extremely dilute suspensions, high salt and elevated temperatures. Furthermore, many applications require close control over their hydrodynamic diameter and interfacial chemistry. These requirements can only be met by irreversible steric stabilization. We describe how such stabilization can be obtained using dispersants anchored by biomimetically inspired, electronegatively substituted catechols, which provide irreversible binding of a high density polymer shell to the particle core by grafting to assembly, in contrast to previously described approaches using e.g. DOPA or dopamine. The novel dispersant stabilization allowed creation of multifunctional SPIONs for targeted biomedical imaging with controlled number of ligands and individually optimized core and shell thicknesses. Furthermore, we present how assembly of core-shell nanoparticles at fluid hydrophobic-hydrophilic interfaces provides a route to create hierarchical smart materials, by allowing control of the geometry of monolayer films of inorganic cores serving as nanoantennas for external stimuli within a responsive matrix. We show how irreversible binding affinity of the hydrophobic or hydrophilic dispersant shell greatly increases NP loading into lipid, polymer and NP only membranes and allows the emergence of well characterized responsive properties.