Design, Synthesis, and Characterization of Magnetite Clusters using a Multi Inlet Vortex Mixer

Superparamagnetic nanoparticles have potential applications in targeted drug delivery and as magnetic resonance imaging contrast agents. Magnetite clusters are of particular interest for these applications because they provide higher magnetic flux (under a magnetic field) than individual magnetite nanoparticles, are biocompatible, and their size and compositions can be controlled. This thesis involves the controlled synthesis and characterization of clusters composed of magnetite nanoparticles stabilized with an amphiphilic block copolymer. It outlines a method to design and form well-defined and colloidally stable magnetite clusters. A Multi Inlet Vortex mixer (MIVM) was used because it is a continuous process that yields particles with relatively narrow and controlled size distributions. In the MIVM, four liquid streams collide under turbulent conditions in the mixing chamber where clusters form within milliseconds. The formation of magnetite clusters was studied in the presence of amphiphilic block copolymers containing poly (ethylene oxide) to provide steric stabilization and control of size distributions using flash nanoprecipitation. First, the mixer was tested using β-carotene as a model compound to form nanoparticles stabilized with an amphiphilic triblock copolymer poly(propylene oxide)-b-poly(ethylene oxide) (F127) at different Reynolds numbers and supersaturation values. Size analysis was done using dynamic light scattering and nanoparticle tracking analysis techniques. The cluster structure was studied using electron microscopy and magnetite compositions were measured using thermogravimetric analysis. Finally, the stability of magnetite clusters was studied over time and the effect of an applied magnetite field on the colloidal stability was investigated.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Macromolecular Science and Engineering

Department dc:contributor.department

Macromolecular Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2010

Author dc:creator

• Mejia-Ariza, Raquel

Chairs dc:contributor.committeechair

• Davis, Richey M.
• Riffle, Judy S.

Committee member dc:contributor.committeemember

• Edgar, Kevin J.

• poly (propylene oxide)
• steric stabilization
• contrast agent
• Rapid nanoprecipitation
• Multi Inlet Vortex Mixer
• magnetite clusters
• poly (ethylene oxide)

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-11012010-115420

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/45432