title: Stable ligand-free stellated polyhedral gold nanoparticles for sensitive plasmonic detection.
abstract: Ligand-free stellated gold nanoparticles (AuStNPs) with well-defined octahedral (O(h)) and icosahedral (I(h)) core symmetries were prepared using hydrogen peroxide as a reducing agent. Only three reagents: gold precursor (HAuCl4), H2O2 and NaOH were required to form colloidally and chemically stable AuStNPs with a zeta-potential between -55 and -40 mV indicative of excellent charge stabilization. The size and degree of stellation of AuStNPs can be controlled by several synthetic parameters so that the localized surface plasmon resonance (LSPR) can be varied from ca. 850 nm in near-infrared (NIR) to ca. 530 nm. In particular, AuStNP size and LSPR tuning can be conveniently accomplished by iodide variation. The size distribution of AuStNPs was improved by nucleation with ascorbic acid, and the AuStNP size and degree of branching could be readily modified using arginine. AuStNPs are advantageous for SPR sensing, as it was demonstrated in the sensitive detection of not only thiols, such as ampicillin, but also iodide with the detection limit of 3.2 pM (0.4 ng L(-1)). The reported ligand-free stable AuStNPs thus should be very useful for biodiagnostics based on SPR sensing and potentially for SERS and hyperthermia therapy.
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Rachel
authors.initials: R
authors.lastname: Keunen
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Danielle
authors.initials: D
authors.lastname: Macoretta
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Nicole
authors.initials: N
authors.lastname: Cathcart
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kitaev
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D017612:Gold Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012972:Sodium Hydroxide / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D020349:Surface Plasmon Resonance
chemical_list: D002712:Chlorides; D017612:Gold Compounds; D008024:Ligands; D012972:Sodium Hydroxide; D006046:Gold; C024568:gold tetrachloride, acid; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid