Issue 5, 2016

Stable ligand-free stellated polyhedral gold nanoparticles for sensitive plasmonic detection

Abstract

Ligand-free stellated gold nanoparticles (AuStNPs) with well-defined octahedral (Oh) and icosahedral (Ih) 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.

Graphical abstract: Stable ligand-free stellated polyhedral gold nanoparticles for sensitive plasmonic detection

Supplementary files

Article information

Article type
Communication
Submitted
10 Dec 2015
Accepted
12 Jan 2016
First published
13 Jan 2016

Nanoscale, 2016,8, 2575-2583

Author version available

Stable ligand-free stellated polyhedral gold nanoparticles for sensitive plasmonic detection

R. Keunen, D. Macoretta, N. Cathcart and V. Kitaev, Nanoscale, 2016, 8, 2575 DOI: 10.1039/C5NR08788K

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