  Currently, magnetic iron oxide nanoparticles are the only nano-sized magnetic
resonance imaging (MRI) contrast agents approved for clinical use, yet
commercial manufacturing of these agents has been limited or discontinued.
Though there is still widespread demand for these particles both for clinical
use and research, they are difficult to obtain commercially, and complicated
syntheses make in-house preparation infeasible for most biological research
labs or clinics. To make commercial production viable and increase
accessibility of these products, it is crucial to develop simple, rapid, and
reproducible preparations of biocompatible iron oxide nanoparticles. Here, we
report a rapid, straightforward microwave-assisted synthesis of
superparamagnetic dextran-coated iron oxide nanoparticles. The nanoparticles
were produced in two hydrodynamic sizes with differing core morphologies by
varying the synthetic method as either a two-step or single step process. A
striking benefit of these methods is the ability to obtain swift and consistent
results without the necessity for air, pH, or temperature sensitive techniques;
therefore, reaction times and complex manufacturing processes are greatly
reduced as compared to conventional synthetic methods. This is a great benefit
for cost-effective translation to commercial production. The nanoparticles are
found to be superparamagnetic and exhibit properties consistent for use in MRI.
In addition, the dextran coating imparts the water-solubility and
biocompatibility necessary for in vivo utilization.
