PEG-stabilized core-shell nanoparticles: impact of linear versus dendritic polymer shell architecture on colloidal properties and the reversibility of temperature-induced aggregation.

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely used experimentally and also clinically tested in diverse areas of biology and medicine. Applications include magnetic resonance imaging, cell sorting, drug delivery, and hyperthermia. Physicochemical surface properties are particularly relevant in the context of achieving high colloidal nanoparticle (NP) stability and preventing agglomeration (particularly challenging in biological fluids), increasing blood circulation time, and possibly targeting specific cells or tissues through the presentation of bioligands.

Self-assembly of focal point oligo-catechol ethylene glycol dendrons on titanium oxide surfaces: adsorption kinetics, surface characterization, and nonfouling properties.

This work covers the synthesis of second-generation, ethylene glycol dendrons covalently linked to a surface anchor that contains two, three, or four catechol groups, the molecular assembly in aqueous buffer on titanium oxide surfaces, and the evaluation of the resistance of the monomolecular adlayers against nonspecific protein adsorption in contact with full blood serum. The results were compared to those of a linear poly(ethylene glycol) (PEG) analogue with the same molecular weight. The adsorption kinetics as well as resulting surface coverages were monitored by ex situ spectroscopic ellipsometry (VASE), in situ optical waveguide lightmode spectroscopy (OWLS), and quartz crystal microbalance with dissipation (QCM-D) investigations.

Ultrastable iron oxide nanoparticle colloidal suspensions using dispersants with catechol-derived anchor groups.

We have found catechol-derivative anchor groups which possess irreversible binding affinity to iron oxide and thus can optimally disperse superparamagnetic nanoparticles under physiologic conditions. This not only leads to ultrastable iron oxide nanoparticles but also allows close control over the hydrodynamic diameter and interfacial chemistry. The latter is a crucial breakthrough to assemble functionalized magnetic nanoparticles, e.