Bioinspired assembly of superparamagnetic nanoparticle membranes

Erik Reimhult
University of Natural Resources and Life Sciences Vienna
Thursday, March 7, 2013
Duke University, Schiciano A | 4:30pm

Nanoparticles with ultrastable and carefully controlled core-shell structures can be used in biomedical applications, e.g., as biomedical imaging contrast agents or in hyperthermia [1]. Exquisite control allows further applications through assembly into biomimetic membrane and vesicular structures for which permeability can externally be controlled by applied magnetic fields. The intrinsic size range of core-shell nanoparticles from that of proteins to viruses makes biomimetic approaches to their assembly into membranes interesting from both an applied and fundamental point of view.

I will describe a new synthetic toolkit built on nitrocatechol dispersants, monodisperse synthesis of Fe3O4 cores using capping agents and a new approach to ligand replacement for shell grafting onto such nanoparticles [2]; but I will focus on our investigations of membrane assembly of superparamagnetic nanoparticles at liquid interfaces including into lipid membranes [3, 4]. The relationship between nanoparticle structure and the assembled membrane structure and the release of model drugs from the formed nanoparticle actuated vesicles will be highlighted. Additionally, new methods to characterize nanoparticles at liquid (membrane) interfaces will be introduced, including measurements of assembled films using X-ray reflectivity at buried interfaces and Freeze-fracture Shadow Casting (FreSCa) to measure single nanoparticle surface energies down to 10 nm in diameter [5].



[1] KK. Smith, Adv. Mater. 2011, 23, 1409–1413 (10pt Tahoma)

[1] E. Amstad, et al., Nanoscale 2011, 3, 2819-2843

[2] E. Amstad, et al., Nano Lett. 2009, 9, 4042-4048

[3] L. Isa, et al., Soft Matt. 2011, 7, 7663-7675

[4] E. Amstad, et al., Nano Lett. 2011, 1664-1670

[5] L. Isa, et al., Nat. Comm. 2011, 2, 438