title: Single-step generation of fluorophore-encapsulated gold nanoparticle core-shell materials.
abstract: We report a simple route to produce fluorophore-encapsulated gold nanoparticles (AuNPs) in a single step under aqueous conditions using the fluorophore 1-pyrenemethylamine (PMA). Different amounts of PMA were used and the resulting core-shell gold nanoparticles were analyzed using UV-visible absorption spectroscopy, fluorescence spectroscopy, and transmission and scanning electron microscopy. Electron microscopy analysis shows nanoparticles consisting of a gold nanoparticle core which is encapsulated with a lower contrast shell. In the UV-visible spectra, we observed a significant red shift (37 nm) of the localized surface plasmon resonance (LSPR) absorption maximum (lambda(max)) compared to citrate-stabilized AuNPs of a similar size. We attribute the prominent LSPR wavelength shift for PMA-AuNP conjugates to the increase in the local dielectric environment near the gold nanoparticles due to the shell formation. This simple, aqueous-based synthesis is a new approach to the production of fluorophore-encapsulated AuNPs that could be applicable in biological sensing systems and photonic device fabrication.
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: R
authors.initials: R
authors.lastname: Sardar
authors.forename: P M
authors.initials: PM
authors.lastname: Shem
authors.forename: C
authors.initials: C
authors.lastname: Pecchia-Bekkum
authors.forename: N S
authors.initials: NS
authors.lastname: Bjorge
authors.forename: J S
authors.initials: JS
authors.lastname: Shumaker-Parry