Effective removal of surface-bound cetyltrimethylammonium ions from thiol-monolayer-protected Au nanorods by treatment with dimethyl sulfoxide/citric acid. Issue 29 (24th March 2017)

• Record Type: Journal Article
• Authors: Nishida, Keisuke; Kawasaki, Hideya
• Is Part Of: RSC advances. Volume 7:Issue 29(2017)
• Page Start: 18041
• Page End: 18045
• Publication Date: 2017-03-24
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra02179h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A simple and effective strategy for removing surface-bound cetyltrimethylammonium (CTA) cations from poly(ethylene glycol)thiolate-protected AuNRs (PEG-AuNRs) by treatment with dimethyl sulfoxide/citric acid (DMSO/Cit). Abstract : Cetyltrimethylammonium bromide (CTAB)-based surfactants are typically used as morphology-directing/stabilising agents for gold nanorods (AuNRs), forming bilayers on their surface. However, the biological applications of AuNRs require the removal of surface-bound CTAB due its high toxicity and the poor colloidal stability of CTAB-covered AuNRs in biological media. Herein, we report a simple and effective strategy for removing surface-bound cetyltrimethylammonium (CTA) cations from poly(ethylene glycol)thiolate-protected AuNRs (PEG-AuNRs) by treatment with dimethyl sulfoxide/citric acid (DMSO/Cit), achieving residual CTA ion levels that cannot be detected by highly sensitive mass spectrometry or X-ray photoelectron spectroscopy (XPS) techniques. The DMSO/Cit treatment is thought to destabilise the Ag–Br–CTA complex on AuNRs, since citric acid forms strongly bound chelate complexes with CTA cations.