Arsonic Acid Functional Polymers Enable Stabilization of Iron Oxide Nanoparticles in Aqueous Solution

The stabilization of iron oxide nanoparticles (IONPs) with polymer coatings has received immense research interest as it improves their aqueous dispersion and enhances their pharmacokinetics and biodistribution. A range of functional groups including carboxylic acids, silanes, catechols, and phosphonic acids have been incorporated into polymers and investigated as anchoring groups for IONPs surfaces. While some anchors suffer from limitations such as low affinity, poor stability and undesirable reactivity with some substrate surfaces, pentavalent phosphonic acid groups have been shown to be one of the most effective. Here, a new and alternative polymer-based stabilization strategy for IONPs in aqueous solution, using arsonic acid functional polymers PEG-b-P(AsAm)-IONPs has been developed. The arsonic acid groups were shown to provide efficient and stable anchoring to the IONPs surface with transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirming particle colloidal stability in water and in phosphate-buffered saline over extended periods of time. Importantly, these polymeric scaffolds are cytocompatible with mouse fibroblast cells (NIH/3T3), encouraging their future biomedical applications.