Citrate-Stabilized Gold Nanorods

Abstract

Stable aqueous dispersions of citrate-stabilized gold nanorods (cit-GNRs) have been prepared in scalable fashion by surfactant exchange from cetyltrimethylammonium bromide (CTAB)-stabilized GNRs, using polystyrenesulfonate (PSS) as a detergent. The surfactant exchange process was monitored by infrared spectroscopy, surface-enhanced Raman scattering (SERS), and X-ray photoelectron spectroscopy (XPS). The latter established the quantitative displacement of CTAB (by PSS) and of PSS (by citrate). The Cit-GNRs are indefinitely stable at low ionic strength, and are conducive to further ligand exchange without loss of dispersion stability. The reliability of the surface exchange process supports the systematic analysis of ligand structure on the hydrodynamic size of GNRs, as described in a companion paper.

Synergistic Effects of Cisplatin Chemotherapy and Gold Nanorod-Mediated Hyperthermia on Ovarian Cancer Cells and Tumors

“…NTA analysis of PEG-GNRs (OD 0.06) indicated a mode peak corresponding to a hydrodynamic diameter (d h ) of 45 nm (Figure 1B), in accord with the TEM analysis [43]. The surface charge density of PEG-GNRs was close to neutral (ζ = −4.93 mV), in accord with previous reports [16,18,20].…”

SERS Nanoparticles in Medicine: From Label-Free Detection to Spectroscopic Tagging

“…184 Other possible solutions involve using reporters that have mutidentate thiol anchors which can remain on the particle surface under high PEG concentrations or methods which can transfer CTAB-coated particles to citrate-coated particles. 253 …”

“…406 To overcome this complication will require that the Raman reporters have moieties such as thiols which have greater affinity than the surfactants or a method which can transfer the particles from surfactant to citrate stabilization. 253 …”

Effective removal of surface-bound cetyltrimethylammonium ions from thiol-monolayer-protected Au nanorods by treatment with dimethyl sulfoxide/citric acid

“…Surface analysis of PEG-AuNRs was performed using XPS, 18,19,[30][31][32] which conrmed the removal of residual CTA cations from PEG-AuNRs aer DMSO/Cit (100 mM) treatment. Fig.…”

“…38 Citric acid is an effective chelating agent, forming complexes with CTA cations and contributing to the dispersion stability of AuNRs via citrate adsorption on their surface. 18 The CTA-citrate complex is believed to dissolve in DMSO, resulting in effective CTA cation removal from PEG-AuNRs. Most likely, therefore, the DMSO/Cit treatment destabilises the Ag-Br-CTA complex on AuNRs.…”