Development of Polymer-Coated Iron Oxide Nanoparticles as Affinity Agents for Polychlorinated Biphenyls: Implications in Remediation and Detection

Polychlorinated biphenyls (PCBs), organic pollutants prevalent in multiple Superfund sites, have proven difficult to remediate due to their high structural stability and their broad environmental presence. PCB contamination is attributed to endothelial dysfunction leading to atheroschlerosis, nonalcoholic steatohepatitis, and is a probable carcinogen.  There is a need to not only address these toxicological implications of PCB contamination, but also to detect and remediate contamination sights.  Currently, though, there remains an unmet need in the ability to rapidly detect and remove PCBs from a variety of environmental water sources. Here, it is hypothesized that magnetic iron oxide core nanoparticles can serve as a platform for the accumulation of PCBs from dilute water sources, enabling rapid detection and remediation processes. Further, the surfaces of these iron oxide nanoparticles can be functionalized to selectively adsorb PCBs from water samples. As initial screening, multiple iron oxide-polymer core-shell nanocomposites were tested to correlate surface chemistry with PCB binding capacity. Chemistries tested include, citric acid, oleic acid, polyphenolic, and polystyrene-based coatings.  FT-IR and GC/MS were used to analyze affinity and absorption characteristics of PCB toward these nanocomposites in aqueous systems.  Citric acid- and oleic acid-coated iron nanoparticles show high binding affinities for PCB-77 with total PCB binding occurring at 0.1 mg/mL and 2 mg/mL particle concentrations, respectively, in PCB-contaminated water samples. Quercetin multi-acrylate (QMA) polyphenolic nanoparticles have been successfully synthesized with iron oxide cores for magnetic separation from contaminated water samples and show effective PCB binding at low particle concentrations.  Toxicity studies have been performed with polystyrene- and QMA-coated iron oxide nanoparticles to show the viability of this method in physiological systems.  Minimal cytotoxicity in human umbilical vein endothelial cells is seen, indicating that these remediation methods potentially can be implemented in environmental and physiological settings.