Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7150123 | Sensors and Actuators B: Chemical | 2012 | 8 Pages |
Abstract
This paper presents a novel, pH-mediated protocol for the surface modification of gold nanorods (GNRs), which provides a robust platform for the assembly of localized surface plasmon resonance (LSPR)-based sensors, by facilitating functionalization at the surface of the nanoparticles. This is achieved by replacing the surface bilayer of cetyltrimethylammonium bromide (CTAB) with 11-mercaptoundecanoic acid (MUA) at alkaline pH after seed-mediated growth of GNRs. This method fully exploits the characteristics of MUA (i) the carboxylic acid functionality enables ligand exchange in an aqueous environment; (ii) the hydrophobic nature of the molecule stabilizes the nanorods and prevents aggregation via a self-assembled monolayer and (iii) the sulfur moiety binds to the gold surface. Critically, this procedure also simplifies subsequent functionalization, overcoming the limitation arising from commonly used CTAB-only preparation. XPS (X-ray photoelectron spectroscopy) was used to confirm the ligand exchange at the surface of the GNRs. The surface modification facilitates the preparation of a LSPR-based biosensor based on human IgG for the detection of anti-human IgG and a detection limit of 0.4Â nM was observed.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Jie Cao, Ewan K. Galbraith, Tong Sun, Kenneth T.V. Grattan,