Structural Investigations on Magneto-Fluorescent-Plasmonic Nanocomposites

摘要

Hybrid nanostructures are a new class of multifunctional materials with unique optical and electronic properties that make them promising for a variety of biological applications and optoelectric devices. In this work, we have designed and studied a tri-functional hybrid nanomaterial consisting of magnetic iron oxide nanoparticles (NPs) as a core material, plasmonic gold (AuNPs) as an interior satellite and fluorescent quantum dots (QDs) as an exterior satellite. Iron oxide NPs were first encapsulated with a lipoic acid (LA) terminated poly-(isoprene)-block- poly(ethylene oxide) diblock copolymer and act as seeds for the reductive deposition of AuNPs. The disulfide moiety of the LA ligand on the surface permitted to stabilize the AuNPs due to the high affinity of Au-to-sulfur. Using the same affinity to Au, QDs encapsulated with similar polymer (QD-LA) were then added to the iron oxide-AuNPs to create a final iron oxide/AuNP/QD hybrid nanomaterial. The structure, size, and morphology of this new, trifunctional hybrid was investigated and confirmed using two distinct transmission electron microscopy (TEM) techniques including cryo transmission electron tomography, as well as high angle annular dark field scanning TEM (HAADF-STEM).