Surface-Modified Iron Oxide Nanoparticle Characterization by Transmission Electron Microscopy
EMSL Project ID
18403
Abstract
Polymer-coated iron oxide nanoparticles have been prepared and initially characterized by dynamic light scattering (DLS), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, transmission electron microscopy (TEM), and chemical assays, but better preparation and analysis techniques by TEM are required for a full understanding of the chemical and physical profile of these and related systems. With the attention of the PNNL/EMSL research staff we hope to compare preparation techniques (differing particle solvents, TEM grids, drying conditions, etc.) and utilize high-grade equipment including a LaB6, EDS-equipped TEM to attain high quality particle imaging and analysis.The Zhang biomaterials laboratory has been working with iron oxide nanoparticles for over four years, and have conjugated and otherwise surface modified these nanoparticles with a multitude of bioactive ligands, fluorophores, therapeutics and biocompatible polymers. Two polymeric-coating systems utilized by our group in current in vitro and in vivo applications include chitosan and poly (ethylene glycol) of varying forms and adhesion mechanisms (i.e. covalent, non-covalent binding).
These products have been shown to maintain a monodisperse, small hydrodynamic size profile as validated by DLS. While this information indicates general successes in particle synthesis and subsequent modification, we hope to demonstrate, visually, the size and surface modification of these particles by TEM/EDS. Standard drying processes can induce particulate agglomeration (due to high nanoparticle surface energy), and high quality images are often dependent upon the grid substrate material, emission voltage, and TEM filament type.
The TEM facility is familiar to our laboratory thanks to work completed there by Jonathan Gunn in January, 2005 during an intensive nanomaterials synthesis and characterization class cosponsored by the University of Washington. At that time, Mr. Gunn worked with senior research scientist, Chongmin Wang, who has offered his assistance for the proposed work. In fact, it has been communicated that there may be overlap in the research goals of these researchers with regard to recent iron oxide nanoparticle-based publications produced by their respective laboratories.
It is our hope, that a basic introduction to the preparatory practices of related nanostructures can enhance the dispersion of the TEM samples, followed by increased contrast and clarity of the modified-particles chosen for analysis. In addition, EDS-analysis will help us map the chemical profile of the nanoparticle coatings, vitally important to the continued progress of the synthesis of new nanoparticle systems by the Zhang laboratory. It is believed, that substantive work can be completed quickly and successfully, due in part to short sample preparation as well as to the familiarity of visiting researchers, Dr. Bhattarai and Mr. Gunn, with current TEM practices and equipment.
Project Details
Project type
Exploratory Research
Start Date
2006-03-20
End Date
2007-03-22
Status
Closed
Released Data Link
Team
Principal Investigator