title: Controlled magnetosomes: Embedding of magnetic nanoparticles into membranes of monodisperse lipid vesicles.
abstract: Magnetic nanoparticle-containing capsules have been proposed for many uses, including triggered drug delivery and imaging. Combining superparamagnetic iron oxide nanoparticles (SPIONs) with existing liposome drug delivery technology is an enticing near-future prospect, but it requires efficient methods of synthesis and formulation compatible with pharmaceutical applications. We report a facile way of producing large, unilamellar, and homogeneously sized magnetoliposomes with high content of monodisperse, hydrophobic SPIONs integrated in the lipid membrane by use of a solvent inversion technique. For low lipid concentrations, unilamellar and monodisperse vesicles were obtained that became increasingly multilamellar with higher lipid fraction. Both, the co-self-assembled structure and loading content were significantly influenced by the purity of the nanoparticle shell. SPIONs with homogeneous shells of nitrodopamine-anchored hydrophobic dispersants could be quantitatively loaded up to 20%w/w, while SPIONs also containing residual physisorbed oleic acid exhibited a loading cut-off around 10%w/w SPIONs accompanied by drastic changes in size distribution. Lipid acyl chain length crucially influenced the formation and resultant stability of the loaded assemblies. The formation of nanoparticle-loaded vesicles is exemplified in different biologically important media, yielding ready-to-use magnetoliposome formulations.
authors.affiliation: Department of Nanobiotechnology, Institute for Biologically Inspired Materials, University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria; School of Materials Science and Engineering, Centre for Biomimetic Senor Science, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553, Singapore.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bixner
authors.affiliation: Department of Nanobiotechnology, Institute for Biologically Inspired Materials, University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria. Electronic address: erik.reimhult@boku.ac.at.
authors.forename: Erik
authors.initials: E
authors.lastname: Reimhult
mesh_terms: D002214:Capsules / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008081:Liposomes / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D055944:Magnetosomes / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D010316:Particle Size; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002214:Capsules; D008081:Liposomes; D058185:Magnetite Nanoparticles; D008563:Membrane Lipids; D012997:Solvents
keywords: Co-self-assembly; Encapsulation; Hydrophobic superparamagnetic iron oxide nanoparticle; Liposome; Magnetoliposome; Solvent inversion